HPAVC/HPAVC CD-ROM.iso/INTER53B.ZIP/INTERRUP.F

Text File | 1997-01-12 | 361KB | 9,224 lines

Interrupt List, part 6 of 16
Copyright (c) 1989,1990,1991,1992,1993,1994,1995,1996,1997 Ralf Brown
--------D-214C-------------------------------
INT 21 - DOS 2+ - "EXIT" - TERMINATE WITH RETURN CODE
    AH = 4Ch
    AL = return code
Return: never returns
Notes:    unless the process is its own parent
      (see #0725 [offset 16h] at AH=26h), all open files are closed and
      all memory belonging to the process is freed
    all network file locks should be removed before calling this function
SeeAlso: AH=00h,AH=26h,AH=4Bh,AH=4Dh,INT 15/AH=12h/BH=02h,INT 20,INT 22
SeeAlso: INT 60/DI=0601h
--------m-214C57-----------------------------
INT 21 - Headroom - ???
    AX = 4C57h
    DS:DX -> target address
Note:    jumps to target address instead of terminating program
SeeAlso: AX=5758h
--------D-214D-------------------------------
INT 21 - DOS 2+ - GET RETURN CODE (ERRORLEVEL)
    AH = 4Dh
Return: AH = termination type
        00h normal (INT 20,INT 21/AH=00h, or INT 21/AH=4Ch)
        01h control-C abort
        02h critical error abort
        03h terminate and stay resident (INT 21/AH=31h or INT 27)
    AL = return code
Notes:    the word in which DOS stores the return code is cleared after being
      read by this function, so the return code can only be retrieved once
    COMMAND.COM stores the return code of the last external command it
      executed as ERRORLEVEL
    this call should not be used if the child was started with AX=4B04h;
      use AH=8Ah instead
    the following sequence will close a Virtual DOS Machine under OS/2 2.0
      through OS/2 Merlin (but may change in the future):
        MOV    AH,4Dh
        INT    21h
        HLT
        DB    02h,0FDh
      This sequence is the only way to close a specific VDM which was
      booted from floppy or a disk image.
SeeAlso: AH=4Bh,AH=4Ch,AH=8Ah
--------D-214E-------------------------------
INT 21 - DOS 2+ - "FINDFIRST" - FIND FIRST MATCHING FILE
    AH = 4Eh
    AL = special flag for use by APPEND (refer to note below)
    CX = file attribute mask (see #0765 at AX=4301h) (bits 0 and 5 ignored)
        0088h (Novell DOS 7) find first deleted file
    DS:DX -> ASCIZ file specification (may include path and wildcards)
Return: CF clear if successful
        Disk Transfer Area filled with FindFirst data block (see #0967)
    CF set on error
        AX = error code (02h,03h,12h) (see #1020 at AH=59h/BX=0000h)
Notes:    for search attributes other than 08h, all files with at MOST the
      specified combination of hidden, system, and directory attributes
      will be returned.  Under DOS 2.x, searching for attribute 08h
      (volume label) will also return normal files, while under DOS 3.0+
      only the volume label (if any) will be returned.
    this call also returns successfully if given the name of a character
      device without wildcards.  DOS 2.x returns attribute 00h, size 0,
      and the current date and time.  DOS 3.0+ returns attribute 40h and
      the current date and time.
    immediately after an INT 2F/AX=B711h (APPEND return found name), the
      name at DS:DX will be overwritten; if AL=00h on entry, the actual
      found pathname will be stored, otherwise, the actual found path
      will be prepended to the original filespec without a path.
    under LANtastic, this call may be used to obtain a list of a server's
      shared resources by searching for "\\SERVER\*.*"; a list of printer
      resources may be obtained by searching for "\\SERVER\@*.*"
    under the FlashTek X-32 DOS extender, the filespec pointer is in DS:EDX
BUGS:    under DOS 3.x and 4.x, the second and subsequent calls to this function
      with a character device name (no wildcards) and search attributes
      which include the volume-label bit (08h) will fail unless there is
      an intervening DOS call which implicitly or explicity performs a
      directory search without the volume-label bit.  Such implicit
      searches are performed by CREATE (AH=3Ch), OPEN (AH=3Dh), UNLINK
      (AH=41h), and RENAME (AH=56h)
    DR DOS 3.41 and 5.0 return the Directory attribute for the volume label
SeeAlso: AH=11h,AH=4Fh,AX=4301h,AX=714Eh,AX=71A1h,AX=F257h/SF=02h
SeeAlso: INT 2F/AX=111Bh,INT 2F/AX=B711h

Format of FindFirst data block:
Offset    Size    Description    (Table 0967)
---PC-DOS 3.10, PC-DOS 4.01, MS-DOS 3.2/3.3/5.0---
 00h    BYTE    drive letter (bits 0-6), remote if bit 7 set
 01h 11 BYTEs    search template
 0Ch    BYTE    search attributes
---DOS 2.x (and some DOS 3.x???)---
 00h    BYTE    search attributes
 01h    BYTE    drive letter
 02h 11 BYTEs    search template
---WILDUNIX.COM---
 00h 12 BYTEs    15-character wildcard search pattern and drive letter (packed)
 0Ch    BYTE    search attributes
---DOS 2.x and most 3.x---
 0Dh    WORD    entry count within directory
 0Fh    DWORD    pointer to DTA???
 13h    WORD    cluster number of start of parent directory
---PC-DOS 4.01, MS-DOS 3.2/3.3/5.0---
 0Dh    WORD    entry count within directory
 0Fh    WORD    cluster number of start of parent directory
 11h  4 BYTEs    reserved
---OS/2 MVDM---
 00h    WORD    "OS2_BMP_handle"
 02h    WORD    "OS2_LastEnt"
 04h    DWORD    "OS2_Checksum"
 08h    BYTE    "OS2_usi_flag"
 09h    DWORD    used by DOS emulator for second pass for volume-label searches
 0Dh    WORD    (ret) "DOS_LastEnt" entry count within directory
 0Fh    BYTE    OS/2 Processed-FindFirst flag
        00h FindFirst processed by DOS
        42h FindFirst processed by OS/2
 10h  5 BYTEs    reserved for future use
---all versions, documented fields---
 15h    BYTE    attribute of file found
 16h    WORD    file time (see #1005 at AX=5700h)
 18h    WORD    file date (see #1006 at AX=5700h)
 1Ah    DWORD    file size
 1Eh 13 BYTEs    ASCIZ filename+extension
--------f-214E-------------------------------
INT 21 - WILDUNIX.COM internal - INSTALLATION CHECK
    AH = 4Eh
    DS:DX = 0000h:0000h
Return: AH = 99h if installed
Program: WILDUNIX.COM is a resident Unix-style wildcard expander by Steve
      Hosgood and Terry Barnaby
--------D-214F-------------------------------
INT 21 - DOS 2+ - "FINDNEXT" - FIND NEXT MATCHING FILE
    AH = 4Fh
    Disk Transfer Area contains data block from previous FindFirst or
      FindNext call
Return: CF clear if successful
        Disk Transfer Area updated
    CF set on error
        AX = error code (12h) (see #1020 at AH=59h/BX=0000h)
Notes:    under Novell DOS 7, if the FindFirst call (AH=4Eh) had CX=0088h, then
      the next matching deleted file will be returned
    since the entire state of a FindFirst/FindNext sequence is contained
      in the data block in the DTA, other disk operations such as renaming,
      moving, deleting, or creating files can cause inaccurate directory
      searches, such as finding the same file twice
BUG:    DR DOS 3.41 and 5.0 return the Directory attribute for the volume label
SeeAlso: AH=12h,AH=4Eh,AX=714Fh,AX=71A1h
--------D-2150-------------------------------
INT 21 - DOS 2+ internal - SET CURRENT PROCESS ID (SET PSP ADDRESS)
    AH = 50h
    BX = segment of PSP for new process
Notes:    DOS uses the current PSP address to determine which processes own files
      and memory; it corresponds to process identifiers used by other OSs
    under DOS 2.x, this function cannot be invoked inside an INT 28h
      handler without setting the Critical Error flag
    under MS-DOS 3.0+ and DR DOS 3.41+, this function does not use any of
      the DOS-internal stacks and may thus be called at any time, even
      during another INT 21h call
    some Microsoft applications such as Quick C 2.51 use segments of 0000h
      and FFFFh and direct access to the SDA (see #1027 at AX=5D06h) to
      test whether they are running under MS-DOS rather than a compatible
      OS; although one should only call this function with valid PSP
      addresses, any program hooking it should be prepared to handle
      invalid addresses
    this function is supported by the OS/2 compatibility box
    this call was undocumented prior to the release of DOS 5.0
SeeAlso: AH=26h,AH=51h,AH=62h
--------v-2150FD-----------------------------
INT 21 - VIRUS - "Predator 2" - INSTALLATION CHECK
    AX = 50FDh
Return: AX = FD50h if resident
SeeAlso: AX=4BFFh"VIRUS",AX=5454h"VIRUS"
--------D-2151-------------------------------
INT 21 - DOS 2+ internal - GET CURRENT PROCESS ID (GET PSP ADDRESS)
    AH = 51h
Return: BX = segment of PSP for current process
Notes:    DOS uses the current PSP address to determine which processes own files
      and memory; it corresponds to process identifiers used by other OSs
    under DOS 2.x, this function cannot be invoked inside an INT 28h
      handler without setting the Critical Error flag
    under DOS 3.0+, this function does not use any of the DOS-internal
      stacks and may thus be called at any time, even during another
      INT 21h call
    supported by OS/2 compatibility box
    identical to the documented AH=62h
    this call was undocumented prior to the release of DOS 5.0
SeeAlso: AH=26h,AH=50h,AH=62h
--------D-2152-------------------------------
INT 21 U - DOS 2+ internal - "SYSVARS" - GET LIST OF LISTS
    AH = 52h
Return: ES:BX -> DOS list of lists (see #0968)
Notes:    partially supported by OS/2 v1.1 compatibility box (however, most
      pointers are FFFFh:FFFFh, LASTDRIVE is FFh, and the NUL header "next"
      pointer is FFFFh:FFFFh).
    partially supported by the Windows NT DOS box; contains only a
      rudimentary Current Directory Structure (see #0986)
    on return, ES points at the DOS data segment (see also INT 2F/AX=1203h)
    Quarterdeck's suggested check for the use of its DOSDATA.SYS or
      DOS-UP.SYS is to test whether the list-of-lists segment is greater
      than the segment of the first memory block; a better check for
      DOS-UP.SYS is INT 21/AX=2B01h/CX=444Dh
    because not all DOS workalikes support all fields in the List of Lists,
      applications should ensure that pointers are neither 0000h:0000h
      nor FFFFh:FFFFh before using them
    Windows for Workgroups 3.11 network and Windows95 set the path to
      the local drive and directory even for network drives; in that
      case the UNC form \\SERVER\SHARE can be obtained with
      INT 21/AX=5F02h or INT 21/AX=5F46h. LapLink RemoteAccess does the
      same even for INT 21/AX=5F02h
    Windows95 GUI no longer returns the true path for a SUBSTed drive,
      but MS-DOS 7.00 does; use INT 21/AH=60h to obtain the true name
SeeAlso: INT 2F/AX=1203h

Format of List of Lists:
Offset    Size    Description    (Table 0968)
 -24    WORD    (DOS 3.1+) contents of CX from INT 21/AX=5E01h
 -22    WORD    (DOS ???+) LRU counter for FCB caching
 -20    WORD    (DOS ???+) LRU counter for FCB opens
 -18    DWORD    (DOS ???+) address of OEM function handler (see INT 21/AH=F8h)
            FFFFh:FFFFh if not installed or not available
 -14    WORD    (DOS ???+) offset in DOS CS of code to return from INT 21 call
 -12    WORD    (DOS 3.1+) sharing retry count (see AX=440Bh)
 -10    WORD    (DOS 3.1+) sharing retry delay (see AX=440Bh)
 -8    DWORD    (DOS 3.0+) pointer to current disk buffer
 -4    WORD    (DOS 3.0+) pointer in DOS data segment of unread CON input
        when CON is read via a handle, DOS reads an entire line,
          and returns the requested portion, buffering the rest
          for the next read.  0000h indicates no unread input
 -2    WORD    segment of first memory control block (see #0969)
 00h    DWORD    pointer to first Drive Parameter Block (see #0742 at AH=32h)
 04h    DWORD    -> first System File Table (see #0980,#0981,#0982,#0983)
 08h    DWORD    pointer to active CLOCK$ device's header (most recently loaded
          driver with CLOCK bit set)
 0Ch    DWORD    pointer to active CON device's header (most recently loaded
          driver with STDIN bit set)
---DOS 2.x---
 10h    BYTE    number of logical drives in system
 11h    WORD    maximum bytes/block of any block device
 13h    DWORD    pointer to first disk buffer (see #0990,#0991)
 17h 18 BYTEs    actual NUL device driver header (not a pointer!)
        NUL is always the first device on DOS's linked list of device
          drivers. (see #0987)
---DOS 3.0---
 10h    BYTE    number of block devices
 11h    WORD    maximum bytes/block of any block device
 13h    DWORD    pointer to first disk buffer (see #0991,#0993)
 17h    DWORD    pointer to array of current directory structures (see #0984)
 1Bh    BYTE    value of LASTDRIVE command in CONFIG.SYS (default 5)
 1Ch    DWORD    pointer to STRING= workspace area
 20h    WORD    size of STRING area (the x in STRING=x from CONFIG.SYS)
 22h    DWORD    pointer to FCB table
 26h    WORD    the y in FCBS=x,y from CONFIG.SYS
 28h 18 BYTEs    actual NUL device driver header (not a pointer!)
        NUL is always the first device on DOS's linked list of device
          drivers. (see #0987)
---DOS 3.1-3.3---
 10h    WORD    maximum bytes per sector of any block device
 12h    DWORD    pointer to first disk buffer in buffer chain (see #0991)
 16h    DWORD    pointer to array of current directory structures (see #0984)
 1Ah    DWORD    pointer to system FCB tables (see #0981,#0982,#0983)
 1Eh    WORD    number of protected FCBs (the y in the CONFIG.SYS FCBS=x,y)
 20h    BYTE    number of block devices installed
 21h    BYTE    number of available drive letters (largest of 5, installed
          block devices, and CONFIG.SYS LASTDRIVE=).  Also size of
          current directory structure array.
 22h 18 BYTEs    actual NUL device driver header (not a pointer!)
        NUL is always the first device on DOS's linked list of device
          drivers. (see #0987)
 34h    BYTE    number of JOIN'ed drives
---DOS 4.x---
 10h    WORD    maximum bytes per sector of any block device
 12h    DWORD    pointer to disk buffer info record (see #0993,#0994)
        Note: although the initialization code in IO.SYS uses this
          pointer, MSDOS.SYS does not, instead using the hardcoded
          address of the info record
 16h    DWORD    pointer to array of current directory structures
        (see #0984,#0985)
 1Ah    DWORD    pointer to system FCB tables (see #0981,#0982,#0983)
 1Eh    WORD    number of protected FCBs (the y in the CONFIG.SYS FCBS=x,y)
        (always 00h for DOS 5.0)
 20h    BYTE    number of block devices installed
 21h    BYTE    number of available drive letters (largest of 5, installed
          block devices, and CONFIG.SYS LASTDRIVE=).  Also size of
          current directory structure array.
 22h 18 BYTEs    actual NUL device driver header (not a pointer!)
        NUL is always the first device on DOS's linked list of device
          drivers. (see #0987)
 34h    BYTE    number of JOIN'ed drives
 35h    WORD    pointer within IBMDOS code segment to list of special program
          names (see #1003)
        (always 0000h for DOS 5.0)
 37h    DWORD    pointer to FAR routine for resident IFS utility functions
        (see #0999)
        may be called by any IFS driver which does not wish to
          service functions 20h or 24h-28h itself
 3Bh    DWORD    pointer to chain of IFS (installable file system) drivers
 3Fh    WORD    the x in BUFFERS x,y (rounded up to multiple of 30 if in EMS)
 41h    WORD    number of lookahead buffers (the y in BUFFERS x,y)
 43h    BYTE    boot drive (1=A:)
 44h    BYTE    flag: 01h to use DWORD moves (80386+), 00h otherwise
 45h    WORD    extended memory size in KB
---DOS 5.0-6.0---
 10h 39 BYTEs    as for DOS 4.x (above)
 37h    DWORD    pointer to SETVER program list or 0000h:0000h
 3Bh    WORD    (DOS=HIGH) offset in DOS CS of function to fix A20 control
          when executing special .COM format
 3Dh    WORD    PSP of most-recently EXECed program if DOS in HMA, 0000h if low
        used for maintaining count of INT 21 calls which disable A20
          on return
 3Fh  8 BYTEs    as for DOS 4.x (above)
---Windows NT DOS Box---
 10h  6 BYTEs    ???
 16h    DWORD    pointer to array of current directory structures (see #0986)
 1Ah  6 BYTEs    ???
 20h    BYTE    number of block devices installed
 21h    BYTE    number of local drive letters (= installed block devices)
        Also size of current directory structure array.
 22h 18 BYTEs    actual NUL device driver header (not a pointer!)
        NUL is always the first device on DOS's linked list of device
          drivers. (see #0987)

Format of DOS memory control block:
Offset    Size    Description    (Table 0969)
 00h    BYTE    block type: 5Ah if last block in chain, otherwise 4Dh
 01h    WORD    PSP segment of owner or special flag value (see #0970)
 03h    WORD    size of memory block in paragraphs
 05h  3 BYTEs    unused by MS-DOS
        (386MAX) if locked-out block, region start/prev region end
---DOS 2.x,3.x---
 08h  8 BYTEs    unused
---DOS 4.0+ ---
 08h  8 BYTEs    ASCII program name if PSP memory block or DR DOS UMB,
          else garbage
        null-terminated if less than 8 characters
Notes:    the next MCB is at segment (current + size + 1)
    under DOS 3.1+, the first memory block is the DOS data segment,
      containing installable drivers, buffers, etc.     Under DOS 4.0+ it is
      divided into subsegments, each with its own memory control block
      (see #0974), the first of which is at offset 0000h.
    for DOS 5+, blocks owned by DOS may have either "SC" or "SD" in bytes
      08h and 09h.    "SC" is system code or locked-out inter-UMB memory,
      "SD" is system data, device drivers, etc.
    Some versions of DR DOS use only seven characters of the program name,
      placing a NUL in the eighth byte.
SeeAlso: #0971,#0973,#0974

(Table 0970)
Values for special flag PSP segments:
 0000h    free
 0006h    DR DOS XMS UMB
 0007h    DR DOS excluded upper memory ("hole")
 0008h    belongs to DOS
 FFF7h    386MAX v6.01+ ???
 FFFAh    386MAX UMB control block (see #0819 at AX=4402h"386MAX")
 FFFDh    386MAX locked-out memory
 FFFEh    386MAX UMB (normally immediately follows its control block)
 FFFFh    386MAX v6.01+ device driver

Format of MS-DOS 5+ UMB control block:
Offset    Size    Description    (Table 0971)
 00h    BYTE    type: 5Ah if last block in chain, 4Dh otherwise
 01h    WORD    first available paragraph in UMB if control block at start
          of UMB, 000Ah if control block at end of UMB
 03h    WORD    length in paragraphs of following UMB or locked-out region
 05h  3 BYTEs    unused
 08h  8 BYTEs    block type name: "UMB" if start block, "SM" if end block in UMB
SeeAlso: #0969,#0972

Format of MS-DOS 7.0 HMA memory control block:
Offset    Size    Description    (Table 0972)
 00h    WORD    signature "MS" (4Dh 53h)
 02h    WORD    usage flag???
        0000h free
        else ???
 04h    WORD    size of memory block in bytes (not counting MCB)
 06h    WORD    offset of next memory block in HMA or 0000h
 08h  8 BYTEs    unused (0)
SeeAlso: #0969,#0971,#0973

Format of STARLITE (General Software's Embedded DOS) memory control block:
Offset    Size    Description    (Table 0973)
 00h    BYTE    block type: 5Ah if last block in chain, otherwise 4Dh
 01h    WORD    PSP segment of owner, 0000h if free, 0008h if belongs to DOS
 03h    WORD    size of memory block in paragraphs
 05h    BYTE    unused
 06h    WORD    segment address of next memory control block (0000h if last)
 08h    WORD    segment address of previous memory control block or 0000h
 0Ah  6 BYTEs    reserved

Format of DOS 4.0+ data segment subsegment control blocks:
Offset    Size    Description    (Table 0974)
 00h    BYTE    subsegment type (blocks typically appear in this order)
        "D"  device driver
        "E"  device driver appendage
        "I"  IFS (Installable File System) driver
             (MS-DOS 7) high-loaded drive data table array (see #1937)
        "F"  FILES=  control block storage area (for FILES>5)
        "X"  FCBS=   control block storage area, if present
        "C"  BUFFERS EMS workspace area (if BUFFERS /X option used)
        "B"  BUFFERS=  storage area
        "L"  LASTDRIVE=     current directory structure array storage area
        "S"  STACKS=  code and data area, if present (see #0975,#0976)
        "T"  INSTALL= transient code
 01h    WORD    paragraph of subsegment start (usually the next paragraph)
 03h    WORD    size of subsegment in paragraphs
 05h  3 BYTEs    unused
 08h  8 BYTEs    for types "D" and "I", base name of file from which the driver
          was loaded (unused for other types)

Format of data at start of STACKS code segment (if present):
Offset    Size    Description    (Table 0975)
 00h    WORD    ???
 02h    WORD    number of stacks (the x in STACKS=x,y)
 04h    WORD    size of stack control block array (should be 8*x)
 06h    WORD    size of each stack (the y in STACKS=x,y)
 08h    DWORD    pointer to STACKS data segment
 0Ch    WORD    offset in STACKS data segment of stack control block array
 0Eh    WORD    offset in STACKS data segment of last element of that array
 10h    WORD    offset in STACKS data segment of the entry in that array for
          the next stack to be allocated (initially same as value in
          0Eh and works its way down in steps of 8 to the value in
          0Ch as hardware interrupts pre-empt each other)
Note:    the STACKS code segment data may, if present, be located as follows:
    DOS 3.2:    The code segment data is at a paragraph boundary fairly early
          in the IBMBIO segment (seen at 0070:0190h)
    DOS 3.3:    The code segment is at a paragraph boundary in the DOS data
          segment, which may be determined by inspecting the segment
          pointers of the vectors for those of interrupts 02h, 08h-0Eh,
          70h, 72-77h which have not been redirected by device drivers
          or TSRs.
    DOS 4.0+    Identified by sub-segment control block type "S" within the DOS
          data segment.
SeeAlso: #0977,INT B4"STACKMAN"

Format of array elements in STACKS data segment:
Offset    Size    Description    (Table 0976)
 00h    BYTE    status: 00h=free, 01h=in use, 03h=corrupted by overflow of
          higher stack.
 01h    BYTE    not used
 02h    WORD    previous SP
 04h    WORD    previous SS
 06h    WORD    ptr to word at top of stack (new value for SP). The word at the
          top of the stack is preset to point back to this control
          block.

Format of SHARE.EXE hooks (DOS 3.1-6.00):
Offset    Size    Description    (Table 0977)
(offsets from first system file table--pointed at by ListOfLists+04h)
-3Ch    DWORD    pointer to FAR routine for ???
        Note: not called by MS-DOS 3.3, set to 0000h:0000h by
            SHARE 3.3+
-38h    DWORD    pointer to FAR routine called on opening file
        on call, internal DOS location points at filename
          (see #1027 at AX=5D06h)
        Return: CF clear if successful
            CF set on error
                AX = DOS error code (24h)
                  (see #1020 at AH=59h/BX=0000h)
        Note: SHARE directly accesses DOS-internal data to get name of
            file just opened
-34h    DWORD    pointer to FAR routine called on closing file
        ES:DI -> system file table
        Note: does something to every Record Lock Record for file
-30h    DWORD    pointer to FAR routine to close all files for given computer
        (called by AX=5D03h)
-2Ch    DWORD    pointer to FAR routine to close all files for given process
        (called by AX=5D04h)
-28h    DWORD    pointer to FAR routine to close file by name
        (called by AX=5D02h)
        DS:SI -> DOS parameter list (see #1026 at AX=5D00h)
           DPL's DS:DX -> name of file to close
        Return: CF clear if successful
            CF set on error
                AX = DOS error code (03h)
                  (see #1020 at AH=59h/BX=0000h)
-24h    DWORD    pointer to FAR routine to lock region of file
        call with BX = file handle
              ---DOS 3.x---
              CX:DX = starting offset
              SI:AX = size
              ---DOS 4.0+ ---
              DS:DX -> lock range
                    DWORD start offset
                    DWORD size in bytes
        Return: CF set on error
                AL = DOS error code (21h) (see #1020 at AH=59h)
        Note: not called if file is marked as remote
-20h    DWORD    pointer to FAR routine to unlock region of file
        call with BX = file handle
              ---DOS 3.x---
              CX:DX = starting offset
              SI:AX = size
              ---DOS 4.0+ ---
              DS:DX -> lock range
                    DWORD start offset
                    DWORD size in bytes
        Return: CF set on error
                AL = DOS error code (21h) (see #1020 at AH=59h)
        Note: not called if file is marked as remote
-1Ch    DWORD    pointer to FAR routine to check if file region is locked
        call with ES:DI -> system file table entry for file
            CX = length of region from current position in file
        Return: CF set if any portion of region locked
                AX = 0021h
-18h    DWORD    pointer to FAR routine to get open file list entry
        (called by AX=5D05h)
        call with DS:SI -> DOS parameter list (see #1026 at AX=5D00h)
            DPL's BX = index of sharing record
            DPL's CX = index of SFT in SFT chain of sharing rec
        Return: CF set on error or not loaded
                AX = DOS error code (12h) (see #1020 at AH=59h)
            CF clear if successful
                ES:DI -> filename
                CX = number of locks owned by specified SFT
                BX = network machine number
                DX destroyed
-14h    DWORD    pointer to FAR routine for updating FCB from SFT???
        call with DS:SI -> unopened FCB
              ES:DI -> system file table entry
        Return: BL = C0h???
        Note: copies following fields from SFT to FCB:
           starting cluster of file      0Bh     1Ah
           sharing record offset      33h     1Ch
           file attribute          04h     1Eh
-10h    DWORD    pointer to FAR routine to get first cluster of FCB file ???
        call with ES:DI -> system file table entry
              DS:SI -> FCB
        Return: CF set if SFT closed or sharing record offsets
                mismatched
            CF clear if successful
                BX = starting cluster number from FCB
-0Ch    DWORD    pointer to FAR routine to close file if duplicate for process
        DS:SI -> system file table
        Return: AX = number of handle in JFT which already uses SFT
        Note: called during open/create of a file
        Note: if SFT was opened with inheritance enabled and sharing
            mode 111, does something to all other SFTs owned by
            same process which have the same file open mode and
            sharing record
-08h    DWORD    pointer to FAR routine for closing file
        Note: closes various handles referring to file most-recently
            opened
-04h    DWORD    pointer to FAR routine to update directory info in related SFT
          entries
        call with ES:DI -> system file table entry for file (see #0982)
              AX = subfunction (apply to each related SFT)
                00h: update time stamp (offset 0Dh) and date
                     stamp (offset 0Fh)
                01h: update file size (offset 11h) and starting
                     cluster (offset 0Bh).  Sets last-accessed
                     cluster fields to start of file if file
                     never accessed
                02h: as function 01h, but last-accessed fields
                     always changed
                03h: do both functions 00h and 02h
        Note: follows ptr at offset 2Bh in system file table entries
        Note: NOP if opened with no-inherit or via FCB
Notes:    most of the above hooks (except -04h, -14h, -18h, and -3Ch) assume
      either that SS=DOS DS or SS=DS=DOS DS and directly access
      DOS-internal data
    sharing hooks are not supported by DR DOS 5-6; they appear to be
      supported by Novell DOS 7, with a segment of 0000h indicating the
      DOS data segment
SeeAlso: #0978,#0979

Format of sharing record:
Offset    Size    Description    (Table 0978)
 00h    BYTE    flag
        00h free block
        01h allocated block
        FFh end marker
 01h    WORD    size of block
 03h    BYTE    checksum of pathname (including NUL)
        if sum of ASCII values is N, checksum is (N/256 + N%256)
 04h    WORD    offset in SHARE's DS of first Record Lock Record (see #0979)
 06h    DWORD    pointer to start of system file table chain for file
 0Ah    WORD    unique sequence number
 0Ch    var    ASCIZ full pathname
Note:    not supported by DR DOS SHARE 1.1 and 2.0; will reportedly be
      supported by Novell DOS 7
SeeAlso: #0977,#0979

Format of SHARE.EXE Record Lock Record:
Offset    Size    Description    (Table 0979)
 00h    WORD    offset in SHARE's DS of next lock table in list or 0000h
 02h    DWORD    offset in file of start of locked region
 06h    DWORD    offset in file of end of locked region
 0Ah    DWORD    pointer to System File Table entry for this file
 0Eh    WORD    PSP segment of lock's owner
---DOS 5+ ---
 10h    WORD    lock type: (00h lock all, 01h lock writes only)
SeeAlso: #0977,#0978,#0980,#0983

Format of DOS 2.x system file tables:
Offset    Size    Description    (Table 0980)
 00h    DWORD    pointer to next file table (offset FFFFh if last)
 04h    WORD    number of files in this table
 06h  28h bytes per file
    Offset    Size    Description
     00h    BYTE    number of file handles referring to this file
     01h    BYTE    file open mode (see #0749 at AH=3Dh)
     02h    BYTE    file attribute
     03h    BYTE    drive (0 = character device, 1 = A, 2 = B, etc)
     04h 11 BYTEs    filename in FCB format (no path,no period,blank-padded)
     0Fh    WORD    ???
     11h    WORD    ???
     13h    DWORD    file size???
     17h    WORD    file date in packed format (see #1006 at AX=5700h)
     19h    WORD    file time in packed format (see #1005 at AX=5700h)
     1Bh    BYTE    device attribute (see #0768 at AX=4400h)
    ---character device---
     1Ch    DWORD    pointer to device driver
    ---block device---
     1Ch    WORD    starting cluster of file
     1Eh    WORD    relative cluster in file of last cluster accessed
    ------
     20h    WORD    absolute cluster number of current cluster
     22h    WORD    ???
     24h    DWORD    current file position???
SeeAlso: #0981,#0982,#0983

Format of DOS 3.0 system file tables and FCB tables:
Offset    Size    Description    (Table 0981)
 00h    DWORD    pointer to next file table (offset FFFFh if last)
 04h    WORD    number of files in this table
 06h  38h bytes per file
    Offset    Size    Description
     00h-1Eh as for DOS 3.1+ (see #0982)
     1Fh    WORD    byte offset of directory entry within sector
     21h 11 BYTEs    filename in FCB format (no path/period, blank-padded)
     2Ch    DWORD    (SHARE.EXE) pointer to previous SFT sharing same file
     30h    WORD    (SHARE.EXE) network machine number which opened file
            (Windows Enhanced mode DOSMGR uses the virtual machine
              ID as the machine number; see INT 2F/AX=1683h)
     32h    WORD    PSP segment of file's owner (first three entries for
              AUX/CON/PRN contain segment of IO.SYS startup code)
     34h    WORD    (SHARE.EXE) offset in SHARE code seg of share record
     36h    WORD    ??? apparently always 0000h
SeeAlso: #0980,#0982,#0983

Format of DOS 3.1-3.3x, DR DOS 5.0-6.0 system file tables and FCB tables:
Offset    Size    Description    (Table 0982)
 00h    DWORD    pointer to next file table (offset FFFFh if last)
 04h    WORD    number of files in this table
 06h  35h bytes per file
    Offset    Size    Description
     00h    WORD    number of file handles referring to this file
     02h    WORD    file open mode (see AX=6C00h, #0749 at AH=3Dh)
            bit 15 set if this file opened via FCB
     04h    BYTE    file attribute (see #0765 at AX=4301h)
     05h    WORD    device info word (see #0768 at AX=4400h)
            bit 15 set if remote file
            bit 14 set means do not set file date/time on closing
            bit 12 set means don't inherit on EXEC
            bits 5-0 drive number for disk files
     07h    DWORD    pointer to device driver header if character device
            else pointer to DOS Drive Parameter Block
              (see #0742 at AH=32h)
     0Bh    WORD    starting cluster of file
     0Dh    WORD    file time in packed format (see #1005 at AX=5700h)
            not used for character devices in DR DOS
     0Fh    WORD    file date in packed format (see #1006 at AX=5700h)
            not used for character devices in DR DOS
     11h    DWORD    file size
    ---system file table---
     15h    DWORD    current offset in file (may be larger than size of
              file; INT 21/AH=42h does not check new position)
    ---FCB table---
     15h    WORD    counter for last I/O to FCB
     17h    WORD    counter for last open of FCB
            (these are separate to determine the times of the
              latest I/O and open)
    ---
     19h    WORD    relative cluster within file of last cluster accessed
     1Bh    WORD    absolute cluster number of last cluster accessed
            0000h if file never read or written???
     1Dh    WORD    number of sector containing directory entry
            (see #0700)
     1Fh    BYTE    number of dir entry within sector (byte offset/32)
     20h 11 BYTEs    filename in FCB format (no path/period, blank-padded)
     2Bh    DWORD    (SHARE.EXE) pointer to previous SFT sharing same file
     2Fh    WORD    (SHARE.EXE) network machine number which opened file
            (Windows Enhanced mode DOSMGR uses the virtual machine
              ID as the machine number; see INT 2F/AX=1683h)
     31h    WORD    PSP segment of file's owner (see #0725 at AH=26h)
              (first three entries for AUX/CON/PRN contain segment
              of IO.SYS startup code)
     33h    WORD    offset within SHARE.EXE code segment of
              sharing record (see #0978) 0000h = none
SeeAlso: #0980,#0981,#0983

Format of DOS 4.0-6.0 system file tables and FCB tables:
Offset    Size    Description    (Table 0983)
 00h    DWORD    pointer to next file table (offset FFFFh if last)
 04h    WORD    number of files in this table
 06h  3Bh bytes per file
    Offset    Size    Description
     00h    WORD    number of file handles referring to this file
            FFFFh if in use but not referenced
     02h    WORD    file open mode (see AX=6C00h,#0749 at AH=3Dh)
            bit 15 set if this file opened via FCB
     04h    BYTE    file attribute (see #0765 at AX=4301h)
     05h    WORD    device info word (see also #0768 at AX=4400h)
            bit 15 set if remote file
            bit 14 set means do not set file date/time on closing
            bit 13 set if named pipe
            bit 12 set if no inherit
            bit 11 set if network spooler
            bit 7  set if device, clear if file (only if local)
            bits 6-0 as for AX=4400h
     07h    DWORD    pointer to device driver header if character device
            else pointer to DOS Drive Parameter Block
              (see #0742 at AH=32h) or REDIR data
     0Bh    WORD    starting cluster of file (local files only)
     0Dh    WORD    file time in packed format (see #1005)
     0Fh    WORD    file date in packed format (see #1006)
     11h    DWORD    file size
     15h    DWORD    current offset in file (SFT)
            LRU counters (FCB table, two WORDs)
    ---local file---
     19h    WORD    relative cluster within file of last cluster accessed
     1Bh    DWORD    number of sector containing directory entry
     1Fh    BYTE    number of dir entry within sector (byte offset/32)
    ---network redirector---
     19h    DWORD    pointer to REDIRIFS record
     1Dh  3 BYTEs    ???
    ------
     20h 11 BYTEs    filename in FCB format (no path/period, blank-padded)
     2Bh    DWORD    (SHARE.EXE) pointer to previous SFT sharing same file
     2Fh    WORD    (SHARE.EXE) network machine number which opened file
            (Windows Enhanced mode DOSMGR uses the virtual machine
              ID as the machine number; see INT 2F/AX=1683h)
     31h    WORD    PSP segment of file's owner (see #0725 at AH=26h)
              (first three entries for AUX/CON/PRN contain segment
              of IO.SYS startup code)
     33h    WORD    offset within SHARE.EXE code segment of
            sharing record (see #0936)  0000h = none
     35h    WORD    (local) absolute cluster number of last clustr accessed
            (redirector) ???
     37h    DWORD    pointer to IFS driver for file, 0000000h if native DOS
Note:    the OS/2 2.0 DOS Boot Session does not properly fill in the filename
      field due to incomplete support for SFTs; the OS/2 2.0 DOS Window
      does not appear to support SFTs at all
SeeAlso: #0980,#0981,#0982

Format of current directory structure (CDS) (array, LASTDRIVE entries):
Offset    Size    Description    (Table 0984)
 00h 67 BYTEs    ASCIZ path in form X:\PATH (local) or UNC form
          \\SERVER\PATH (network, see notes below)
 43h    WORD    drive attributes (also see note below) (see also AX=5F07h)
        bit 15: uses network redirector     \ invalid if 00, installable
        bit 14: physical drive         / file system if 11
        bit 13: JOIN'ed      \ path above is true path that would be
        bit 12: SUBST'ed  / needed if not under SUBST or JOIN
        bit  7: remote drive hidden from redirector's assign-list and
              exempt from network connection make/break commands;
              set for CD-ROM drives by MSCDEX (not supported by
              CORELCDX)
 45h    DWORD    pointer to Drive Parameter Block for drive
          (see #0742 at AH=32h)
---local drives---
 49h    WORD    starting cluster of current directory
        0000h = root, FFFFh = never accessed
 4Bh    WORD    ??? seems to be FFFFh always
 4Dh    WORD    ??? seems to be FFFFh always
---network drives---
 49h    DWORD    pointer to redirector or REDIRIFS record, or FFFFh:FFFFh
        (DOS 4 only) available for use by IFS driver
 4Dh    WORD    stored user data from INT 21/AX=5F03h
------
 4Fh    WORD    offset in current directory path of backslash corresponding to
          root directory for drive
        this value specifies how many characters to hide from the
          "CHDIR" and "GETDIR" calls; normally set to 2 to hide the
          drive letter and colon, SUBST, JOIN, and networks change it
          so that only the appropriate portion of the true path is
          visible to the user
---DOS 4.0+ ---
 51h    BYTE    (DOS 4 only, remote drives) device type
        04h network drive
 52h    DWORD    pointer to IFS driver (DOS 4) or redirector block (DOS 5+) for
          this drive, 00000000h if native DOS
 56h    WORD    available for use by IFS driver
Notes:    the path for invalid drives is normally set to X:\, but may be empty
      after JOIN x: /D in DR DOS 5.0 or NET USE x: /D in older LAN versions
    normally, only one of bits 13&12 may be set together with bit 14, but
      DR DOS 5.0 uses other combinations for bits 15-12: 0111 JOIN,
      0001 SUBST, 0101 ASSIGN (see #0985)
    Windows for Workgroups 3.11 network sets the path to the local
      drive and directory even for network drives; in that case the
      UNC form \\SERVER\SHARE can be obtained with INT 21/AX=5F02h
      or INT 21/AX=5F46h. LapLink RemoteAccess does the same even for
      INT 21/AX=5F02h
    SoftWindows on the Macintosh PowerPC sets \\E for the host drive
SeeAlso: #0985,INT 21/AX=71AAh/BL=00h

Format of DR DOS 5.0-6.0 current directory structure entry (array):
Offset    Size    Description    (Table 0985)
 00h 67 BYTEs    ASCIZ pathname of actual root directory for this logical drive
 43h    WORD    drive attributes
        1000h SUBSTed drive
        3000h??? JOINed drive
        4000h physical drive
        5000h ASSIGNed drive
        7000h JOINed drive
        8000h network drive
 45h    BYTE    physical drive number (0=A:) if this logical drive is valid
 46h    BYTE    ??? apparently flags for JOIN and ASSIGN
 47h    WORD    cluster number of start of parent directory (0000h = root)
 49h    WORD    entry number of current directory in parent directory
 4Bh    WORD    cluster number of start of current directory
 4Dh    WORD    used for media change detection (details not available)
 4Fh    WORD    cluster number of SUBST/JOIN "root" directory
        0000h if physical root directory
SeeAlso: #0984

Format of Windows NT Current Directory Structure (CDS) (array):
Offset    Size    Description    (Table 0986)
 00h 67 BYTEs    ASCIZ path in form X:\ (does not show either current directory
          or network path)
 43h  4 BYTEs    ???
Note:    the WinNT CDS contains only as many entries as there are local drives,
      not LASTDRIVE entries.

Format of DOS device driver header:
Offset    Size    Description    (Table 0987)
 00h    DWORD    pointer to next driver, offset=FFFFh if last driver
 04h    WORD    device attributes (see #0988,#0989)
 06h    WORD    device strategy entry point
        call with ES:BX -> request header
          (see #1931 at INT 2F/AX=0802h)
 08h    WORD    device interrupt entry point
---character device---
 0Ah  8 BYTEs    blank-padded character device name
---block device---
 0Ah    BYTE    number of subunits (drives) supported by driver
 0Bh  7 BYTEs    normally unused; sometimes contains signature to indicate
          specific drivers:
        "$PCMATA"   PCMCIA driver PCMATA.SYS (see AX=440Dh"DOS 3.2+")
        "AHADDVR"   Adaptec SCSI disk driver ASPIDISK.SYS
        "DBLSPAC"   MS DoubleSpace or DriveSpace
        "DSKREET"   NortonUtils v5+ Diskreet (see INT 2F/AX=FE00h)
        "GFS    "   LapLink III device driver DD.BIN
        "SIDExxx"   PCMCIA driver ATADRV.EXE (see AX=440Dh"DOS 3.2+")
        "STAC-CD"   Stacker/Stacker Anywhere (see AX=4404h"Stacker")
---DoubleSpace/DriveSpace---
 12h  2 BYTEs    signature ",." (2Ch 2Eh)
 14h    var    preloading API entry point
---CD-ROM---
 12h    WORD    reserved, must be 0000h
        appears to be another device chain
 14h    BYTE    drive letter (must initially be 00h; this byte is set by
          MSCDEX when it loads)
 15h    BYTE    number of units
 16h  6 BYTEs    signature 'MSCDnn' where 'nn' is version (currently '00')
SeeAlso: #1886 at INT 25/AX=CDCDh,#2124 at INT 2F/AX=5600h

Bitfields for device attributes (character device):
Bit(s)    Description    (Table 0988)
 15    set (indicates character device)
 14    IOCTL supported (see AH=44h)
 13    (DOS 3.0+) output until busy supported
 12    reserved
 11    (DOS 3.0+) OPEN/CLOSE/RemMedia calls supported
 10-8    reserved
 7    (DOS 5.0+) Generic IOCTL check call supported (driver command 19h)
    (see AX=4410h,AX=4411h)
 6    (DOS 3.2+) Generic IOCTL call supported (driver command 13h)
    (see AX=440Ch,AX=440Dh"DOS 3.2+")
 5    reserved
 4    device is special (use INT 29 "fast console output")
 3    device is CLOCK$ (all reads/writes use transfer record described
      below)
 2    device is NUL
 1    device is standard output
 0    device is standard input
Note:    for European MS-DOS 4.0, bit 11 also indicates that bits 8-6 contain a
      version code (000 = DOS 3.0,3.1; 001 = DOS 3.2;
      010 = European DOS 4.0)
SeeAlso: #0989,#0987

Bitfields for device attributes (block device):
Bit(s)    Description    (Table 0989)
 15    clear (indicates block device)
 14    IOCTL supported
 13    non-IBM format
 12    network device (device is remote)
 11    (DOS 3.0+) OPEN/CLOSE/RemMedia calls supported
 10    reserved
 9    direct I/O not allowed??? (set by DOS 3.3 DRIVER.SYS for "new" drives)
 8    ??? set by DOS 3.3 DRIVER.SYS for "new" drives
 7    (DOS 5.0+) Generic IOCTL check call supported (driver command 19h)
    (see AX=4410h,AX=4411h)
 6    (DOS 3.2+) Generic IOCTL call supported (driver command 13h)
    implies support for commands 17h and 18h
      (see AX=440Ch,AX=440Dh"DOS 3.2+",AX=440Eh,AX=440Fh)
 5-2    reserved
 1    driver supports 32-bit sector addressing (DOS 3.31+)
 0     reserved
Note:    for European MS-DOS 4.0, bit 11 also indicates that bits 8-6 contain a
      version code (000 = DOS 3.0,3.1; 001 = DOS 3.2;
      010 = European DOS 4.0)
SeeAlso: #0988,#0987

Format of DOS 2.x disk buffer:
Offset    Size    Description    (Table 0990)
 00h    DWORD    pointer to next disk buffer, offset = FFFFh if last
        least-recently used buffer is first in chain
 04h    BYTE    drive (0=A, 1=B, etc), FFh if not in use
 05h  3 BYTEs    unused??? (seems always to be 00h 00h 01h)
 08h    WORD    logical sector number
 0Ah    BYTE    number of copies to write (1 for non-FAT sectors)
 0Bh    BYTE    sector offset between copies if multiple copies to be written
 0Ch    DWORD    pointer to DOS Drive Parameter Block (see #0742 at AH=32h)
 10h        buffered data
SeeAlso: #0991,#0993,#0994,#0996

Format of DOS 3.x disk buffer:
Offset    Size    Description    (Table 0991)
 00h    DWORD    pointer to next disk buffer, offset = FFFFh if last
        least-recently used buffer is first in chain
 04h    BYTE    drive (0=A,1=B, etc), FFh if not in use
 05h    BYTE    buffer flags (see #0992)
 06h    WORD    logical sector number
 08h    BYTE    number of copies to write (1 for non-FAT sectors)
 09h    BYTE    sector offset between copies if multiple copies to be written
 0Ah    DWORD    pointer to DOS Drive Parameter Block (see #0742 at AH=32h)
 0Eh    WORD    unused??? (almost always 0)
 10h        buffered data
SeeAlso: #0990,#0993,#0994,#0996

Bitfields for DOS 3.x disk buffer flags:
Bit(s)    Description    (Table 0992)
 7    ???
 6    buffer dirty
 5    buffer has been referenced
 4    ???
 3    sector in data area
 2    sector in a directory, either root or subdirectory
 1    sector in FAT
 0    boot sector??? (guess)
SeeAlso: #0997

Format of DOS 4.00 (pre UR 25066) disk buffer info:
Offset    Size    Description    (Table 0993)
 00h    DWORD    pointer to array of disk buffer hash chain heads (see #0995)
 04h    WORD    number of disk buffer hash chains (referred to as NDBCH below)
 06h    DWORD    pointer to lookahead buffer, zero if not present
 0Ah    WORD    number of lookahead sectors, else zero (the y in BUFFERS=x,y)
 0Ch    BYTE    00h if buffers in EMS (/X), FFh if not
 0Dh    WORD    EMS handle for buffers, zero if not in EMS
 0Fh    WORD    EMS physical page number used for buffers (usually 255)
 11h    WORD    ??? seems always to be 0001h
 13h    WORD    segment of EMS physical page frame
 15h    WORD    ??? seems always to be zero
 17h  4 WORDs    EMS partial page mapping information???
SeeAlso: #0990,#0991,#0994,#0998

Format of DOS 4.01 (from UR 25066 Corrctive Services Disk on) disk buffer info:
Offset    Size    Description    (Table 0994)
 00h    DWORD    pointer to array of disk buffer hash chain heads (see #0995)
 04h    WORD    number of disk buffer hash chains (referred to as NDBCH below)
 06h    DWORD    pointer to lookahead buffer, zero if not present
 0Ah    WORD    number of lookahead sectors, else zero (the y in BUFFERS=x,y)
 0Ch    BYTE    01h, possibly to distinguish from pre-UR 25066 format
 0Dh    WORD    ??? EMS segment for BUFFERS (only with /XD)
 0Fh    WORD    ??? EMS physical page number of EMS seg above (only with /XD)
 11h    WORD    ??? EMS segment for ??? (only with /XD)
 13h    WORD    ??? EMS physical page number of above (only with /XD)
 15h    BYTE    ??? number of EMS page frames present (only with /XD)
 16h    WORD    segment of one-sector workspace buffer allocated in main memory
          if BUFFERS/XS or /XD options in effect, possibly to avoid DMA
          into EMS
 18h    WORD    EMS handle for buffers, zero if not in EMS
 1Ah    WORD    EMS physical page number used for buffers (usually 255)
 1Ch    WORD    ??? appears always to be 0001h
 1Eh    WORD    segment of EMS physical page frame
 20h    WORD    ??? appears always to be zero
 22h    BYTE    00h if /XS, 01h if /XD, FFh if BUFFERS not in EMS
SeeAlso: #0990,#0991,#0993,#0998

Format of DOS 4.x disk buffer hash chain head (array, one entry per chain):
Offset    Size    Description    (Table 0995)
 00h    WORD    EMS logical page number in which chain is resident, -1 if not
          in EMS
 02h    DWORD    pointer to least recently used buffer header.  All buffers on
          this chain are in the same segment.
 06h    BYTE    number of dirty buffers on this chain
 07h    BYTE    reserved (00h)
Notes:    buffered disk sectors are assigned to chain N where N is the sector's
      address modulo NDBCH,     0 <= N <= NDBCH-1
    each chain resides completely within one EMS page
    this structure is in main memory even if buffers are in EMS

Format of DOS 4.0-6.0 disk buffer:
Offset    Size    Description    (Table 0996)
 00h    WORD    forward ptr, offset only, to next least recently used buffer
 02h    WORD    backward pointer, offset only
 04h    BYTE    drive (0=A,1=B, etc) if bit 7 clear
        SFT index if bit 7 set
        FFh if not in use
 05h    BYTE    buffer flags (see #0997)
 06h    DWORD    logical sector number (local buffers only)
 0Ah    BYTE    number of copies to write
        for FAT sectors, same as number of FATs
        for data and directory sectors, usually 1
 0Bh    WORD    offset in sectors between copies to write for FAT sectors
 0Dh    DWORD    pointer to DOS Drive Parameter Block (see #0742 at AH=32h)
 11h    WORD    size of data in buffer if remote buffer (see also #0997)
 13h    BYTE    reserved (padding)
 14h        buffered data
Note:    for DOS 4.x, all buffered sectors which have the same hash value
      (computed as the sum of high and low words of the logical sector
      number divided by the number of disk buffer chains) are on the same
      doubly-linked circular chain; for DOS 5+, only a single circular
      chain exists.
    the links consist of offset addresses only, the segment being the same
      for all buffers in the chain.
SeeAlso: #0990,#0991,#0993

Bitfields for DOS 4.0-6.0 disk buffer flags:
Bit(s)    Description    (Table 0997)
 7    remote buffer
 6    buffer dirty
 5    buffer has been referenced (reserved in DOS 5+)
 4    search data buffer (only valid if remote buffer)
 3    sector in data area
 2    sector in a directory, either root or subdirectory
 1    sector in FAT
 0    reserved
SeeAlso: #0992

Format of DOS 5.0-6.0 disk buffer info:
Offset    Size    Description    (Table 0998)
 00h    DWORD    pointer to least-recently-used buffer header (may be in HMA)
        (see #0996)
 04h    WORD    number of dirty disk buffers
 06h    DWORD    pointer to lookahead buffer, zero if not present
 0Ah    WORD    number of lookahead sectors, else zero (the y in BUFFERS=x,y)
 0Ch    BYTE    buffer location
        00h base memory, no workspace buffer
        01h HMA, workspace buffer in base memory
 0Dh    DWORD    pointer to one-segment workspace buffer in base memory
 11h  3 BYTEs    unused
 14h    WORD    ???
 16h    BYTE    flag: INT 24 fail while making an I/O status call
 17h    BYTE    temp storage for user memory allocation strategy during EXEC
 18h    BYTE    counter: number of INT 21 calls for which A20 is off
 19h    BYTE    bit flags
        bit 0: ???
        bit 1: SWITCHES=/W specified in CONFIG.SYS (don't load
            WINA20.SYS when MS Windows 3.0 starts)
        bit 2: in EXEC state (INT 21/AX=4B05h)
 1Ah    WORD    offset of unpack code start (used only during INT 21/AX=4B05h)
 1Ch    BYTE    bit 0 set iff UMB MCB chain linked to normal MCB chain
 1Dh    WORD    minimum paragraphs of memory required by program being EXECed
 1Fh    WORD    segment of first MCB in upper memory blocks or FFFFh if DOS
          memory chain in base 640K only (first UMB MCB usually at
          9FFFh, locking out video memory with a DOS-owned memory
          block)
        the MCB this word points at contains a valid link into high
          memory even if it is marked with a 'Z' indicating the last
          memory block
 21h    WORD    paragraph from which to start scanning during memory allocation
SeeAlso: #0993,#0994

(Table 0999)
Call IFS utility function entry point with:
    AH = 20h miscellaneous functions
        AL = 00h get date
        Return: CX = year
            DH = month
            DL = day
        AL = 01h get process ID and computer ID
        Return: BX = current PSP segment
            DX = active network machine number
        AL = 05h get file system info
        ES:DI -> 16-byte info buffer
        Return: buffer filled
            Offset    Size    Description
             00h  2 BYTEs    unused
             02h    WORD    number of SFTs (actually counts only
                    the first two file table arrays)
             04h    WORD    number of FCB table entries
             06h    WORD    number of proctected FCBs
             08h  6 BYTEs    unused
             0Eh    WORD    largest sector size supported
        AL = 06h get machine name
        ES:DI -> 18-byte buffer for name
        Return: buffer filled with name starting at offset 02h
        AL = 08h get sharing retry count
        Return: BX = sharing retry count
        AL = other
        Return: CF set
    AH = 21h get redirection state
        BH = type (03h disk, 04h printer)
        Return: BH = state (00h off, 01h on)
    AH = 22h ??? some sort of time calculation
        AL = 00h ???
            nonzero ???
    AH = 23h ??? some sort of time calculation
    AH = 24h compare filenames
        DS:SI -> first ASCIZ filename
        ES:DI -> second ASCIZ filename
        Return: ZF set if files are same ignoring case and / vs \
    AH = 25h normalize filename
        DS:SI -> ASCIZ filename
        ES:DI -> buffer for result
        Return: filename uppercased, forward slashes changed to backslashes
    AH = 26h get DOS stack
        Return: DS:SI -> top of stack
            CX = size of stack in bytes
    AH = 27h increment InDOS flag
    AH = 28h decrement InDOS flag
Note:    IFS drivers which do not wish to implement functions 20h or 24h-28h may
      pass them on to the default handler pointed at by [LoL+37h]
SeeAlso: #1000,#1001

Format of IFS driver list:
Offset    Size    Description    (Table 1000)
 00h    DWORD    pointer to next driver header
 04h  8 BYTEs    IFS driver name (blank padded), as used by FILESYS command
 0Ch  4 BYTEs    ???
 10h    DWORD    pointer to IFS utility function entry point (see #0999)
        call with ES:BX -> IFS request (see #1001)
 14h    WORD    offset in header's segment of driver entry point
    ???
SeeAlso: #0999,#1001

Format of IFS request block:
Offset    Size    Description    (Table 1001)
 00h    WORD    total size in bytes of request
 02h    BYTE    class of request
        02h ???
        03h redirection
        04h ???
        05h file access
        06h convert error code to string
        07h ???
 03h    WORD    returned DOS error code
 05h    BYTE    IFS driver exit status
        00h success
        01h ???
        02h ???
        03h ???
        04h ???
        FFh internal failure
 06h 16 BYTEs    ???
---request class 02h---
 16h    BYTE    function code
        04h ???
 17h    BYTE    unused???
 18h    DWORD    pointer to ???
 1Ch    DWORD    pointer to ???
 20h  2 BYTEs    ???
---request class 03h---
 16h    BYTE    function code
 17h    BYTE    ???
 18h    DWORD    pointer to ???
 1Ch    DWORD    pointer to ???
 22h    WORD    returned ???
 24h    WORD    returned ???
 26h    WORD    returned ???
 28h    BYTE    returned ???
 29h    BYTE    unused???
---request class 04h---
 16h    DWORD    pointer to ???
 1Ah    DWORD    pointer to ???
---request class 05h---
 16h    BYTE    function code
        01h flush disk buffers
        02h get disk space
        03h MKDIR
        04h RMDIR
        05h CHDIR
        06h delete file
        07h rename file
        08h search directory
        09h file open/create
        0Ah LSEEK
        0Bh read from file
        0Ch write to file
        0Dh lock region of file
        0Eh commit/close file
        0Fh get/set file attributes
        10h printer control
        11h ???
        12h process termination
        13h ???
    ---class 05h function 01h---
     17h  7 BYTEs    ???
     1Eh    DWORD    pointer to ???
     22h  4 BYTEs    ???
     26h    BYTE    ???
     27h    BYTE    ???
    ---class 05h function 02h---
     17h  7 BYTEs    ???
     1Eh    DWORD    pointer to ???
     22h  4 BYTEs    ???
     26h    WORD    returned total clusters
     28h    WORD    returned sectors per cluster
     2Ah    WORD    returned bytes per sector
     2Ch    WORD    returned available clusters
     2Eh    BYTE    returned ???
     2Fh    BYTE    ???
    ---class 05h functions 03h,04h,05h---
     17h  7 BYTEs    ???
     1Eh    DWORD    pointer to ???
     22h  4 BYTEs    ???
     26h    DWORD    pointer to directory name
    ---class 05h function 06h---
     17h  7 BYTEs    ???
     1Eh    DWORD    pointer to ???
     22h  4 BYTEs    ???
     26h    WORD    attribute mask
     28h    DWORD    pointer to filename
    ---class 05h function 07h---
     17h  7 BYTEs    ???
     1Eh    DWORD    pointer to ???
     22h  4 BYTEs    ???
     26h    WORD    attribute mask
     28h    DWORD    pointer to source filespec
     2Ch    DWORD    pointer to destination filespec
    ---class 05h function 08h---
     17h  7 BYTEs    ???
     1Eh    DWORD    pointer to ???
     22h  4 BYTEs    ???
     26h    BYTE    00h FINDFIRST
            01h FINDNEXT
     28h    DWORD    pointer to FindFirst search data + 01h if FINDNEXT
     2Ch    WORD    search attribute if FINDFIRST
     2Eh    DWORD    pointer to filespec if FINDFIRST
    ---class 05h function 09h---
     17h  7 BYTEs    ???
     1Eh    DWORD    pointer to ???
     22h    DWORD    pointer to IFS open file structure (see #1002)
     26h    WORD    ???  \ together, specify open vs. create, whether or
     28h    WORD    ???  / not to truncate
     2Ah  4 BYTEs    ???
     2Eh    DWORD    pointer to filename
     32h  4 BYTEs    ???
     36h    WORD    file attributes on call
            returned ???
     38h    WORD    returned ???
    ---class 05h function 0Ah---
     17h  7 BYTEs    ???
     1Eh    DWORD    pointer to ???
     22h    DWORD    pointer to IFS open file structure (see #1002)
     26h    BYTE    seek type (02h = from end)
     28h    DWORD    offset on call
            returned new absolute position
    ---class 05h functions 0Bh,0Ch---
     17h  7 BYTEs    ???
     1Eh    DWORD    pointer to ???
     22h    DWORD    pointer to IFS open file structure (see #1002)
     28h    WORD    number of bytes to transfer
            returned bytes actually transferred
     2Ah    DWORD    transfer address
    ---class 05h function 0Dh---
     17h  7 BYTEs    ???
     1Eh    DWORD    pointer to ???
     22h    DWORD    pointer to IFS open file structure (see #1002)
     26h    BYTE    file handle???
     27h    BYTE    unused???
     28h    WORD    ???
     2Ah    WORD    ???
     2Ch    WORD    ???
     2Eh    WORD    ???
    ---class 05h function 0Eh---
     17h  7 BYTEs    ???
     1Eh    DWORD    pointer to ???
     22h    DWORD    pointer to IFS open file structure (see #1002)
     26h    BYTE    00h commit file
            01h close file
     27h    BYTE    unused???
    ---class 05h function 0Fh---
     17h  7 BYTEs    ???
     1Eh    DWORD    pointer to ???
     22h  4 BYTEs    ???
     26h    BYTE    02h GET attributes
            03h PUT attributes
     27h    BYTE    unused???
     28h 12 BYTEs    ???
     34h    WORD    search attributes???
     36h    DWORD    pointer to filename
     3Ah    WORD    (GET) returned ???
     3Ch    WORD    (GET) returned ???
     3Eh    WORD    (GET) returned ???
     40h    WORD    (GET) returned ???
     42h    WORD    (PUT) new attributes
            (GET) returned attributes
    ---class 05h function 10h---
     17h  7 BYTEs    ???
     1Eh    DWORD    pointer to ???
     22h    DWORD    pointer to IFS open file structure (see #1002)
     26h    WORD    ???
     28h    DWORD    pointer to ???
     2Ch    WORD    ???
     2Eh    BYTE    ???
     2Fh    BYTE    subfunction
            01h get printer setup
            03h ???
            04h ???
            05h ???
            06h ???
            07h ???
            21h set printer setup
    ---class 05h function 11h---
     17h  7 BYTEs    ???
     1Eh    DWORD    pointer to ???
     22h    DWORD    pointer to IFS open file structure (see #1002)
     26h    BYTE    subfunction
     27h    BYTE    unused???
     28h    WORD    ???
     2Ah    WORD    ???
     2Ch    WORD    ???
     2Eh    BYTE    ???
     2Fh    BYTE    ???
    ---class 05h function 12h---
     17h 15 BYTEs    unused???
     26h    WORD    PSP segment
     28h    BYTE    type of process termination
     29h    BYTE    unused???
    ---class 05h function 13h---
     17h 15 BYTEs    unused???
     26h    WORD    PSP segment
---request class 06h---
 16h    DWORD    returned pointer to string corresponding to error code at 03h
 1Ah    BYTE    returned ???
 1Bh    BYTE    unused
---request class 07h---
 16h    DWORD    pointer to IFS open file structure (see #1002)
 1Ah    BYTE    ???
 1Bh    BYTE    unused???
SeeAlso: #1000,#0999,#1002

Format of IFS open file structure:
Offset    Size    Description    (Table 1002)
 00h    WORD    ???
 02h    WORD    device info word
 04h    WORD    file open mode
 06h    WORD    ???
 08h    WORD    file attributes
 0Ah    WORD    owner's network machine number
 0Ch    WORD    owner's PSP segment
 0Eh    DWORD    file size
 12h    DWORD    current offset in file
 16h    WORD    file time
 18h    WORD    file date
 1Ah 11 BYTEs    filename in FCB format
 25h    WORD    ???
 27h    WORD    hash value of SFT address
        (low word of linear address + segment&F000h)
 29h  3 WORDs    network info from SFT
 2Fh    WORD    ???

Format of one item in DOS 4.0+ list of special program names:
Offset    Size    Description    (Table 1003)
 00h    BYTE    length of name (00h = end of list)
 01h  N BYTEs    name in format name.ext
 N    2 BYTEs    DOS version to return for program (major,minor)
        (see AH=30h,INT 2F/AX=122Fh)
---DOS 4 only---
 N+2    BYTE    number of times to return fake version number (FFh = always)
Note:    if the name of the executable for the program making the DOS "get
      version" call matches one of the names in this list, DOS returns the
      specified version rather than the true version number
--------v-215252-----------------------------
INT 21 - VIRUS - "516"/"Leapfrog" - INSTALLATION CHECK
    AX = 5252h
Return: BX = FFEEh if resident
SeeAlso: AX=4BFFh"Cascade",AX=58CCh
--------D-2153-------------------------------
INT 21 - DOS 2+ internal - TRANSLATE BIOS PARAMETER BLOCK TO DRIVE PARAM BLOCK
    AH = 53h
    DS:SI -> BIOS Parameter Block (see #1004)
    ES:BP -> buffer for Drive Parameter Block (see #0742 at AH=32h)
Return: ES:BP buffer filled
Notes:    for DOS 3.0+, the cluster at which to start searching is set to 0000h
      and the number of free clusters is set to FFFFh (unknown)
    if the number of sectors per cluster is set to zero, MS-DOS will hang
      at startup because it computes the internally-used shift count by
      shifting this value right until the carry flag is set; since this
      will never happen when the field is zero, MS-DOS hangs
    not supported by Windows NT 3.1

Format of BIOS Parameter Block:
Offset    Size    Description    (Table 1004)
 00h    WORD    number of bytes per sector
 02h    BYTE    number of sectors per cluster
 03h    WORD    number of reserved sectors at start of disk
 05h    BYTE    number of FATs
 06h    WORD    number of entries in root directory
 08h    WORD    total number of sectors
        for DOS 4.0+, set to zero if partition >32M, then set DWORD at
          15h to actual number of sectors
 0Ah    BYTE    media ID byte (see #0703)
 0Bh    WORD    number of sectors per FAT
---DOS 2.13---
 0Dh    WORD    number of sectors per track
 0Fh    WORD    number of heads
 11h    WORD    number of hidden sectors
---DOS 3.0+ ---
 0Dh    WORD    number of sectors per track
 0Fh    WORD    number of heads
 11h    DWORD    number of hidden sectors
 15h 11 BYTEs    reserved
---DOS 4.0+ ---
 15h    DWORD    total number of sectors if word at 08h contains zero
 19h  6 BYTEs    ???
 1Fh    WORD    number of cylinders
 21h    BYTE    device type
 22h    WORD    device attributes (removable or not, etc)
---DR DOS 5+ ---
 15h    DWORD    total number of sectors if word at 08h contains zero
 19h  6 BYTEs    reserved
---European MS-DOS 4.00---
 15h    DWORD    total number of sectors if word at 08h contains zero
        (however, this DOS does not actually implement >32M partitions)
SeeAlso: #0742,#3300

Format of Extended BIOS Parameter Block:
Offset    Size    Description    (Table 3300)
 00h 25 BYTEs    same as standard DOS 4-6 BPB (see #1004)
 19h    DWORD    sectors per FAT if WORD at 0Bh is 0000h
 1Dh    WORD    extended flags
        bits 3-0: the 0-based FAT number of the active FAT
        bits 6-4: reserved (0)
        bit 7: do not mirror active FAT to inactive FATs
 1Fh    WORD    file system version (high byte=major, low byte=minor)
 21h    DWORD    starting cluster number of root directory
 25h    WORD    file system information sector number (see also #3296)
 29h  6 WORDs    reserved
SeeAlso: #0902
--------D-2154-------------------------------
INT 21 - DOS 2+ - GET VERIFY FLAG
    AH = 54h
Return: AL = verify flag
        00h off
        01h on (all disk writes verified after writing)
SeeAlso: AH=2Eh
--------v-2154--BX4475-----------------------
INT 21 - VIRUS - "Dual_GtM"/"Ganeu" - INSTALLATION CHECK
    AH = 54h
    BX = 4475h ("Du")
    CX = 616Ch ("al")
Return: BX = 4774h ("Gt") and CX = 4D21h ("M!") if resident
SeeAlso: AX=50FDh"VIRUS",AX=5454h"VIRUS"
--------v-215454-----------------------------
INT 21 - VIRUS - "Dudley" - INSTALLATION CHECK
    AX = 5454h
Return: AX = 0000h if resident
SeeAlso: AX=50FDh"VIRUS",AH=54h/BX=4475h"VIRUS",AX=7BCEh"VIRUS"
--------D-2155-------------------------------
INT 21 - DOS 2+ internal - CREATE CHILD PSP
    AH = 55h
    DX = segment at which to create new PSP
    SI = (DOS 3.0+) value to place in memory size field at DX:[0002h]
Return: AL destroyed
Notes:    creates a "child" PSP rather than making an exact copy of the current
      PSP; the new PSP's parent pointer is set to the current PSP and the
      reference count for each inherited file is incremented
    (DOS 2.0+) sets current PSP to DX
    (DOS 3.0+) marks "no inherit" file handles as closed in child PSP
    this function is implemented using the same code as AH=26h, so unlike
      other DOS 2+ functions, it does not return status in CF, instead
      returning status in AL as DOS 1.x functions do (but it never puts an
      explicit return value in AL)
SeeAlso: AH=26h,AH=50h
--------D-2156-------------------------------
INT 21 - DOS 2+ - "RENAME" - RENAME FILE
    AH = 56h
    DS:DX -> ASCIZ filename of existing file (no wildcards, but see below)
    ES:DI -> ASCIZ new filename (no wildcards)
    CL = attribute mask (server call only, see below)
Return: CF clear if successful
    CF set on error
        AX = error code (02h,03h,05h,11h) (see #1020)
Notes:    allows move between directories on same logical volume
    this function does not set the archive attribute
      (see #0765 at AX=4301h), which results in incremental backups not
      backing up the file under its new name
    open files should not be renamed
    (DOS 2.x only) this function renames file by creating a new directory
      entry with the new name,then marking the old entry deleted
    (DOS 3.0+) allows renaming of directories
    (DOS 3.1+) wildcards are allowed if invoked via AX=5D00h, in which case
      error 12h (no more files) is returned on success, and both source and
      destination specs must be canonical (as returned by AH=60h).
      Wildcards in the destination are replaced by the corresponding char
      of each source file being renamed.  Under DOS 3.x, the call will fail
      if the destination wildcard is *.* or equivalent; under DR DOS 5.0,
      the call will fail if any wildcards are used.     When invoked via
      AX=5D00h, only those files matching the attribute mask in CL are
      renamed.
    under the FlashTek X-32 DOS extender, the old-name pointer is in DS:EDX
      and the new-name pointer is in ES:EDI (DS must equal ES)
BUG:    (DR DOS 3.41) when invoked via AX=5D00h, this function will generate
      a new directory entry with the new name (including any wildcards)
      which can only be removed with a sector editor
SeeAlso: AH=17h,AX=4301h,AX=5D00h,AH=60h,AH=71h,AX=F257h/SF=04h
--------v-215643------------------------
INT 21 - VIRUS - "PS-MPC.Gold" - INSTALLATION CHECK
    AX = 5643h  ('VC')
Return: AX = 5053h  ('PS') if resident
SeeAlso: AX=33E0h"VIRUS",AX=5741h"VIRUS",AX=6303h"VIRUS"
--------D-215700-----------------------------
INT 21 - DOS 2+ - GET FILE'S LAST-WRITTEN DATE AND TIME
    AX = 5700h
    BX = file handle
Return: CF clear if successful
        CX = file's time (see #1005)
        DX = file's date (see #1006)
    CF set on error
        AX = error code (01h,06h) (see #1020)
Note:    under DR DOS 3.41 and 5.0, this function returns 0 (no date/time) for
      character devices; MS-DOS returns date and time of opening
SeeAlso: AX=5701h,AX=5704h"Windows95"

Bitfields for file time:
Bit(s)    Description    (Table 1005)
 15-11    hours (0-23)
 10-5    minutes
 4-0    seconds/2

Bitfields for file date:
Bit(s)    Description    (Table 1006)
 15-9    year - 1980
 8-5    month
 4-0    day
--------D-215701-----------------------------
INT 21 - DOS 2+ - SET FILE'S LAST-WRITTEN DATE AND TIME
    AX = 5701h
    BX = file handle
    CX = new time (see #1005)
    DX = new date (see #1006)
Return: CF clear if successful
    CF set on error
        AX = error code (01h,06h) (see #1020)
SeeAlso: AX=5700h,AX=5705h"Windows95",AX=5707h"Windows95"
--------D-215702-----------------------------
INT 21 - DOS 4.x only - GET EXTENDED ATTRIBUTES FOR FILE
    AX = 5702h
    BX = file handle
    CX = size of result buffer or 0000h
    DS:SI -> EAP list (see #1007)
    ES:DI -> buffer for returned EAV list (see #1010)
Return: CF clear if successful
        CX = size of returned data
    CF set on error
        AX = error code (see #1020)
Desc:    get the current value of one or more extended attributes
Notes:    if CX=0000h on entry, ES:DI is ignored and no data is actually
      returned, only the amount of data which is available
    the default DOS 4 behavior is to return a single word of 0000h (no
      structures) in the result buffer if CX>=0002h on entry; this
      functionality was apparently never released to the public
SeeAlso: AX=5703h,AX=5704h,AH=6Eh,INT 2F/AX=112Dh

Format of EAP (extended attribute properties) list:
Offset    Size    Description    (Table 1007)
 00h    WORD    number of EAP structures following
 02h    var    array of EAP structures (see #1008)
SeeAlso: #1010

Format of EAP (extended attribute property) structure:
Offset    Size    Description    (Table 1008)
 00h    BYTE    attribute type
        01h boolean (either 00h or 01h)
        02h number (BYTE, WORD, or DWORD)
        03h string
        04h date stamp
        05h time stamp
 01h    WORD    EAP flags (see #1009)
 03h    BYTE    size of reference string (name)
 04h  N BYTEs    reference string

Bitfields for EAP flags:
Bit(s)    Description    (Table 1009)
 12    unchangeable
 13    ignore
 14    unchangeable
 15    used by COMMAND.COM for code page, but not understood by ATTRIB

Format of EAV (extended attribute value) list:
Offset    Size    Description    (Table 1010)
 00h    WORD    number of EAV structures following
 02h    var    array of Extended Attribute Value structures (see #1011)
SeeAlso: #1007

Format of Extended Attribute Value structures:
Offset    Size    Description    (Table 1011)
 00h  4 BYTEs    ???
 04h    BYTE    size of reference string
 05h    WORD    size of value
 07h    var    reference string
    var    value
--------O-215702-----------------------------
INT 21 - OS/2 v1.1+ Family API - DosQFileInfo
    AX = 5702h
    BX = file handle
    CX = size of buffer for information
    DX = level of information
        0001h standard file information (see #1012)
        0002h Query EA Size (see #1012)
        0003h Query EAs from List (see #1013)
        0004h Query All EAs (see #1013)
    ES:DI -> buffer for information (see #1012,#1013)
Return: CF clear if successful
    CF set on error
        AX = error code
SeeAlso: AX=5702h/BX=FFFFh,AX=5703h"OS/2",AH=6Dh"OS/2"

Format of OS/2 DosQFileInfo:
Offset    Size    Description    (Table 1012)
 00h    WORD    creation date
 02h    WORD    creation time
 04h    WORD    last access date
 06h    WORD    last access time
 08h    WORD    last write date
 0Ah    WORD    last write time
 0Ch    DWORD    file size in bytes
 10h    DWORD    allocated space in bytes
 14h    WORD    file attributes
---level 2 only---
 16h    DWORD    size of Extended Attributes in byte
SeeAlso: #1013,#1016

Format of OS/2 DosQFileInfo, EAOP structure:
Offset    Size    Description    (Table 1013)
 00h    DWORD    pointer to general EA list (see #1014)
 04h    DWORD    pointer to buffer for full EA list, with length field set
 08h    DWORD    (ret) error
Note:    for info level 3, the first pointer must contain the address of a
      list of the Extended Attributes to be retrieved; for info level 4,
      it should be 0000h:0000h
SeeAlso: #1012,#1016

Format of OS/2 DosQFileInfo, General EA List:
Offset    Size    Description    (Table 1014)
 00h    DWORD    (call) total size of list in bytes (including this field)
        (ret) number of bytes actually used (including this field)
 04h    var    Extended Attribute entries (see #1015) [packed arrray]

Format of OS/2 DosQFileInfo, General EA entry:
Offset    Size    Description    (Table 1015)
 00h    BYTE    length of Extended Attribute name (excluding terminating NUL)
 01h  N BYTEs    EA name
    BYTE    00h
SeeAlso: #1014

Format of OS/2 DosQFileInfo, Full EA List:
Offset    Size    Description    (Table 1016)
 00h    DWORD    (call) total size of list in bytes (including this field)
        (ret) number of bytes actually used (including this field)
 04h    var    Extended Attribute data (see #1017) [packed array]
SeeAlso: #1012,#1013

Format of OS/2 Extended Attribute data (struct FEA):
Offset    Size    Description    (Table 1017)
 00h    BYTE    flags
        bit 7: critical EA
 01h    BYTE    length of Extended Attribute name (excluding terminating NUL)
 02h    WORD    length of Extended Attribute value
 04h  N BYTEs    EA name
    BYTE    00h
      M BYTEs    EA value
--------O-215702BXFFFF-----------------------
INT 21 - OS/2 v1.1+ Compatibility Box Family API - DosQPathInfo
    AX = 5702h
    BX = FFFFh
    CX = size of buffer for information
    DX = level of information (0002h)
    DS:SI -> filename
    ES:DI -> buffer for FAPI path information (see #1018)
Return: CF clear if successful
        AL = 00h
    CF set on error
        AX = error code
SeeAlso: AX=5702h"OS/2",AX=5703h/BX=FFFFh

Format of FAPI path information:
Offset    Size    Description    (Table 1018)
 00h 22 BYTEs    ???
 16h    DWORD    extended attribute size (none present if less than 5)
--------D-215703-----------------------------
INT 21 - DOS 4.x only - GET EXTENDED ATTRIBUTE PROPERTIES
    AX = 5703h
    BX = file handle
    CX = size of result buffer or 0000h
    ES:DI -> result buffer
Return: CF clear if successful
        CX = size of returned data
    CF set on error
        AX = error code (see #1020)
    ES:DI -> zero word (DOS 4.0) if CX >= 2 on entry
Desc:    get a list of the extended attributes which are defined for the
      specified file
Notes:    if CX=0000h on entry, ES:DI is ignored and no data is actually
      returned, only the amount of data which is available
    the default DOS 4 behavior is to return a trivial EAP list consisting
      of the single word 0000h (no EAP structures) if CX>=0002h on entry;
      this functionality was apparently never released to the public
SeeAlso: AX=5702h,AX=5704h,AH=6Eh,INT 2F/AX=112Dh
--------O-215703-----------------------------
INT 21 - OS/2 v1.1+ Family API - DosSetFileInfo
    AX = 5703h
    BX = file handle
    CX = size of information buffer
    DX = level of information
    ES:DI -> information buffer
Return: CF clear if successful
    CF set on error
        AX = error code
SeeAlso: AX=5702h"OS/2",AX=5703h/BX=FFFFh
--------O-215703BXFFFF-----------------------
INT 21 - OS/2 v1.1+ Family API - DosSetPathInfo
    AX = 5703h
    BX = FFFFh
    CX = size of information buffer
    DX = level of information
    DS:SI -> filename
    ES:DI -> information buffer
Return: CF clear if successful
    CF set on error
        AX = error code
SeeAlso: AX=5702h/BX=FFFFh,AX=5703h"OS/2"
--------D-215704-----------------------------
INT 21 - DOS 4.x only - SET EXTENDED ATTRIBUTES
    AX = 5704h
    BX = file handle
    ES:DI -> EAV list (see #1010)
Return: CF clear if successful
    CF set on error
        AX = error code (see #1020)
Note:    the default DOS 4 behavior is to do nothing and return successfully;
      this functionality was apparently never released to the public
SeeAlso: AX=5702h,AX=5703h,INT 2F/AX=112Dh
--------D-215704-----------------------------
INT 21 - MS-DOS 7/Windows95 - GET LAST ACCESS DATE AND TIME
    AX = 5704h
    BX = file handle
Return: CF clear if successful
        DX = last access date (see #1006)
        CX = last access time (currently always 0000h)
    CF set on error
        AX = error code
SeeAlso: AX=5701h,AX=5705h,AX=5706h
--------D-215705-----------------------------
INT 21 - MS-DOS 7/Windows95 - SET LAST ACCESS DATE AND TIME
    AX = 5705h
    BX = file handle
    CX = new last-access time (currently not supported, must be 0000h)
    DX = new last-access date (see #1006)
Return: CF clear if successful
    CF set on error
        AX = error code
SeeAlso: AX=5700h,AX=5704h"Windows95",AX=5707h
--------D-215706-----------------------------
INT 21 - MS-DOS 7/Windows95 - GET CREATION DATE AND TIME
    AX = 5706h
    BX = file handle
Return: CF clear if successful
        CX = creation time (see #1005)
        DX = creation date (see #1006)
        SI = number of 10-millisecond units past time in CX (0-199)
    CF set on error
        AX = error code
SeeAlso: AX=5701h,AX=5704h"Windows95",AX=5707h
--------D-215707-----------------------------
INT 21 - MS-DOS 7/Windows95 - SET CREATION DATE AND TIME
    AX = 5707h
    BX = file handle
    CX = new creation time (see #1005)
    DX = new creation date (see #1006)
    SI = new creation time: 10-millisecond units past time in CX (0-199)
Return: CF clear if successful
    CF set on error
        AX = error code
SeeAlso: AX=5700h,AX=5705h,AX=5706h
--------v-215741-----------------------------
INT 21 - VIRUS - "WARP" -INSTALLATION CHECK
    AX = 5741h
Return: AX = 5250h if resident
SeeAlso: AX=5643h"VIRUS",AX=58CCh"VIRUS"
--------U-215757BX5757-----------------------
INT 21 U - IBM Genie - Resident Manager - INSTALLATION CHECK
    AX = 5757h
    BX = 5757h
Return: AX = 0000h if installed
        BX = ???
        DX = ???
        DS:SI -> list of 27 DWORD entry point addresses
Program: IBM Genie is a set of utility TSRs by Helix Software
Note:    other functions possible if BX <> 5757h, but details not yet available
----------215758-----------------------------
INT 21 U - Headroom - API
    AX = 5758h
    BL = function
        00h ???
        01h get Headroom location
        Return: CF clear if installed
                AX = PSP segment of Headroom TSR
                BX = paragraphs of memory used by Headroom
            CF set if not (normal DOS return)
        Note:    this function is also used as an installation check
        02h get INT 21 handler
        Return: CF clear
            ES:BX -> Headroom's INT 21 handler
        Note: also sets unknown flag
        03h launch application???
        DS:SI -> 233-byte application record
        Return: ???
        04h ???
        ???
        Return: CF clear
        05h get swap directory
        Return: CF clear
            DX:AX -> ASCIZ swap directory name
        06h ???
        DX = ???
        Return: CF clear
        07h ???
        08h ???
        09h get current application
        Return: BX = application number
        0Ah ???
        DX = application number
        DS:SI = ???
        Return: ???
        0Bh ???
        0Ch ???
        DX = application number
        ???
        Return: ???
        0Dh ???
        DX = application number
        ???
        Return: ???
        0Eh get ???
        Return: CF clear
            AX = ???
        0Fh set ??? flag
        10h clear ??? flag
        11h find application by name
        DS:SI -> ASCIZ application name
        Return: CF clear
            AX = application number or FFFFh if not loaded
        12h ???
        DX = application number
        Return: CF clear
            ???
        13h ???
        Return: CF clear
        14h ???
        same as function 13h
        15h set ???
        DX = ???
        16h get ???
        Return: AX = ??? set by function 15h
        17h get ???
        Return: BX = ???
            CX = ??? (may be pointer in BX:CX)
        18h BUG: branches incorrectly due to fencepost error
Program: Headroom is a TSR/task switcher by Helix Software
SeeAlso: AX=4C57h,AX=5757h,INT 2F/AX=5758h
--------D-2158-------------------------------
INT 21 - DOS 2.11+ - GET OR SET MEMORY ALLOCATION STRATEGY
    AH = 58h
    AL = subfunction
        00h get allocation strategy
        Return: AX = current strategy (see #1019)
        01h set allocation strategy
        BL = new allocation strategy (see #1019)
        BH = 00h (DOS 5+)
Return: CF clear if successful
    CF set on error
        AX = error code (01h) (see #1020)
Notes:    the Set subfunction accepts any value in BL for DOS 3.x and 4.x;
      2 or greater means last fit
    the Get subfunction returns the last value set
    setting an allocation strategy involving high memory does not
      automatically link in the UMB memory chain; this must be done
      explicitly with AX=5803h in order to actually allocate high memory
    a program which changes the allocation strategy should restore it
      before terminating
    Toshiba MS-DOS v2.11 supports subfunctions 00h and 01h, as does the
      TI Professional MS-DOS v2.13
    DR DOS 3.41 reportedly reverses subfunctions 00h and 01h
SeeAlso: AH=48h,AH=49h,AH=4Ah,INT 2F/AX=4310h"XMS",INT 67/AH=3Fh

(Table 1019)
Values for DOS memory allocation strategy:
 00h low memory first fit
 01h low memory best fit
 02h low memory last fit
---DOS 5+ ---
 40h high memory first fit
 41h high memory best fit
 42h high memory last fit
 80h first fit, try high then low memory
 81h best fit, try high then low memory
 82h last fit, try high then low memory
--------D-2158-------------------------------
INT 21 - DOS 5+ - GET OR SET UMB LINK STATE
    AH = 58h
    AL = subfunction
        02h get UMB link state
        Return: AL = current link state
                00h UMBs not part of DOS memory chain
                01h UMBs in DOS memory chain
        03h set UMB link state
        BX = new link state
            0000h remove UMBs from DOS memory chain
            0001h add UMBs to DOS memory chain
Return: CF clear if successful
    CF set on error
        AX = error code (01h) (see #1020)
Notes:    a program which changes the UMB link state should restore it before
      terminating
    UMBs will only be available if CONFIG.SYS contains the line DOS=UMB,
      the UMBs have been linked into the memory chain with AX=5803h, and
      the allocation strategy has been set to include high memory with
      AX=5801h
SeeAlso: #1027,#2046 at INT 2F/AX=4310h
--------v-2158CC-----------------------------
INT 21 - VIRUS - "1067"/"Headcrash" - INSTALLATION CHECK
    AX = 58CCh
Return: CF clear if resident
SeeAlso: AX=5741h"VIRUS",AX=5643h,AX=5252h,AX=58DDh,AX=6303h"VIRUS",AX=6969h
--------v-2158DD-----------------------------
INT 21 - VIRUS - "1067"/"Headcrash" - GET ORIGINAL INT 21h VECTOR
    AX = 58DDh
Return: CX = code segment of virus
    ES:BX = old INT 21h vector
SeeAlso: AX=5252h,AX=58CCh,AX=6969h
--------D-2159--BX0000-----------------------
INT 21 - DOS 3.0+ - GET EXTENDED ERROR INFORMATION
    AH = 59h
    BX = 0000h
Return: AX = extended error code (see #1020)
    BH = error class (see #1022)
    BL = recommended action (see #1023)
    CH = error locus (see #1024)
    ES:DI may be pointer (see #1021, #1020)
    CL, DX, SI, BP, and DS destroyed
Notes:    functions available under DOS 2.x map the true DOS 3.0+ error code into
      one supported under DOS 2.x
    you should call this function to retrieve the true error code when an
      FCB or DOS 2.x call returns an error
    under DR DOS 5.0, this function does not use any of the DOS-internal
      stacks and may thus be called at any time
SeeAlso: AH=59h/BX=0001h,AX=5D0Ah,INT 2F/AX=122Dh

(Table 1020)
Values for DOS extended error code:
 00h (0)   no error
 01h (1)   function number invalid
 02h (2)   file not found
 03h (3)   path not found
 04h (4)   too many open files (no handles available)
 05h (5)   access denied
 06h (6)   invalid handle
 07h (7)   memory control block destroyed
 08h (8)   insufficient memory
 09h (9)   memory block address invalid
 0Ah (10)  environment invalid (usually >32K in length)
 0Bh (11)  format invalid
 0Ch (12)  access code invalid
 0Dh (13)  data invalid
 0Eh (14)  reserved
 0Fh (15)  invalid drive
 10h (16)  attempted to remove current directory
 11h (17)  not same device
 12h (18)  no more files
---DOS 3.0+ ---
 13h (19)  disk write-protected
 14h (20)  unknown unit
 15h (21)  drive not ready
 16h (22)  unknown command
 17h (23)  data error (CRC)
 18h (24)  bad request structure length
 19h (25)  seek error
 1Ah (26)  unknown media type (non-DOS disk)
 1Bh (27)  sector not found
 1Ch (28)  printer out of paper
 1Dh (29)  write fault
 1Eh (30)  read fault
 1Fh (31)  general failure
 20h (32)  sharing violation
 21h (33)  lock violation
 22h (34)  disk change invalid (ES:DI -> media ID structure)(see #1021)
 23h (35)  FCB unavailable
 24h (36)  sharing buffer overflow
 25h (37)  (DOS 4.0+) code page mismatch
 26h (38)  (DOS 4.0+) cannot complete file operation (out of input)
 27h (39)  (DOS 4.0+) insufficient disk space
 28h-31h   reserved
 32h (50)  network request not supported
 33h (51)  remote computer not listening
 34h (52)  duplicate name on network
 35h (53)  network name not found
 36h (54)  network busy
 37h (55)  network device no longer exists
 38h (56)  network BIOS command limit exceeded
 39h (57)  network adapter hardware error
 3Ah (58)  incorrect response from network
 3Bh (59)  unexpected network error
 3Ch (60)  incompatible remote adapter
 3Dh (61)  print queue full
 3Eh (62)  queue not full
 3Fh (63)  not enough space to print file
 40h (64)  network name was deleted
 41h (65)  network: Access denied
 42h (66)  network device type incorrect
 43h (67)  network name not found
 44h (68)  network name limit exceeded
 45h (69)  network BIOS session limit exceeded
 46h (70)  temporarily paused
 47h (71)  network request not accepted
 48h (72)  network print/disk redirection paused
 49h (73)  network software not installed
        (LANtastic) invalid network version
 4Ah (74)  unexpected adapter close
        (LANtastic) account expired
 4Bh (75)  (LANtastic) password expired
 4Ch (76)  (LANtastic) login attempt invalid at this time
 4Dh (77)  (LANtastic v3+) disk limit exceeded on network node
 4Eh (78)  (LANtastic v3+) not logged in to network node
 4Fh (79)  reserved
 50h (80)  file exists
 51h (81)  reserved
 52h (82)  cannot make directory
 53h (83)  fail on INT 24h
 54h (84)  (DOS 3.3+) too many redirections
 55h (85)  (DOS 3.3+) duplicate redirection
 56h (86)  (DOS 3.3+) invalid password
 57h (87)  (DOS 3.3+) invalid parameter
 58h (88)  (DOS 3.3+) network write fault
 59h (89)  (DOS 4.0+) function not supported on network
 5Ah (90)  (DOS 4.0+) required system component not installed
 5Bh (91)  (NetWare4) timer server table overflowed
 5Ch (92)  (NetWare4) duplicate in timer service table
 5Dh (93)  (NetWare4) no items to work on
 5Fh (95)  (NetWare4) invalid interrupt
 64h (100) (MSCDEX) unknown error
 64h (100) (NetWare4) open semaphore limit exceeded
 65h (101) (MSCDEX) not ready
 65h (101) (NetWare4) exclusive semaphore is already owned
 66h (102) (MSCDEX) EMS memory no longer valid
 66h (102) (NetWare4) semaphore was set when close attempted
 67h (103) (MSCDEX) not High Sierra or ISO-9660 format
 67h (103) (NetWare4) too many exclusive semaphore requests
 68h (104) (MSCDEX) door open
 68h (104) (NetWare4) operation invalid from interrupt handler
 69h (105) (NetWare4) semaphore owner died
 6Ah (106) (NetWare4) semaphore limit exceeded
 6Bh (107) (NetWare4) insert drive B: disk into drive A:
 6Ch (108) (NetWare4) drive locked by another process
 6Dh (109) (NetWare4) broken pipe
 6Eh (110) (NetWare4) pipe open/create failed
 6Fh (111) (NetWare4) pipe buffer overflowed
 70h (112) (NetWare4) disk full
 71h (113) (NetWare4) no more search handles
 72h (114) (NetWare4) invalid target handle for dup2
 73h (115) (NetWare4) bad user virtual address
 74h (116) (NetWare4) error on console I/O
 75h (117) (NetWare4) unknown category code for IOCTL
 76h (118) (NetWare4) invalid value for verify flag
 77h (119) (NetWare4) level four driver not found
 78h (120) (NetWare4) invalid function number
 79h (121) (NetWare4) semaphore timeout
 7Ah (122) (NetWare4) buffer too small
 7Bh (123) (NetWare4) invalid character or bad file-system name
 7Ch (124) (NetWare4) unimplemented information level
 7Dh (125) (NetWare4) no volume label found
 7Eh (126) (NetWare4) module handle not found
 7Fh (127) (NetWare4) procedure address not found
 80h (128) (NetWare4) CWait found no children
 81h (129) (NetWare4) CWait children still running
 82h (130) (NetWare4) invalid operation for direct disk-access handle
 83h (131) (NetWare4) attempted seek to negative offset
 84h (132) (NetWare4) attempted to seek on device or pipe
 85h (133) (NetWare4) drive already has JOINed drives
 86h (134) (NetWare4) drive is already JOINed
 87h (135) (NetWare4) drive is already SUBSTed
 88h (136) (NetWare4) can not delete drive which is not JOINed
 89h (137) (NetWare4) can not delete drive which is not SUBSTed
 8Ah (138) (NetWare4) can not JOIN to a JOINed drive
 8Bh (139) (NetWare4) can not SUBST to a SUBSTed drive
 8Ch (140) (NetWare4) can not JOIN to a SUBSTed drive
 8Dh (141) (NetWare4) can not SUBST to a JOINed drive
 8Eh (142) (NetWare4) drive is busy
 8Fh (143) (NetWare4) can not JOIN/SUBST to same drive
 90h (144) (NetWare4) directory must not be root directory
 91h (145) (NetWare4) can only JOIN to empty directory
 92h (146) (NetWare4) path is already in use for SUBST
 93h (147) (NetWare4) path is already in use for JOIN
 94h (148) (NetWare4) path is in use by another process
 95h (149) (NetWare4) directory previously SUBSTituted
 96h (150) (NetWare4) system trace error
 97h (151) (NetWare4) invalid event count for DosMuxSemWait
 98h (152) (NetWare4) too many waiting on mutex
 99h (153) (NetWare4) invalid list format
 9Ah (154) (NetWare4) volume label too large
 9Bh (155) (NetWare4) unable to create another TCB
 9Ch (156) (NetWare4) signal refused
 9Dh (157) (NetWare4) segment discarded
 9Eh (158) (NetWare4) segment not locked
 9Fh (159) (NetWare4) invalid thread-ID address
 A0h (160) (NetWare4) bad environment pointer
 A1h (161) (NetWare4) invalid name passed to EXEC
 A2h (162) (NetWare4) signal already pending
 A3h (163) (NetWare4) ERROR_124 mapping
 A4h (164) (NetWare4) no more process slots
 A5h (165) (NetWare4) ERROR_124 mapping
 B0h (176) (MS-DOS 7.0) volume is not locked
 B1h (177) (MS-DOS 7.0) volume is locked in drive
 B2h (178) (MS-DOS 7.0) volume is not removable
 B4h (180) (MS-DOS 7.0) lock count has been exceeded
 B4h (180) (NetWare4) invalid segment number
 B5h (181) (MS-DOS 7.0) a valid eject request failed
 B5h (181) (NetWare4) invalid call gate
 B6h (182) (NetWare4) invalid ordinal
 B7h (183) (NetWare4) shared segment already exists
 B8h (184) (NetWare4) no child process to wait for
 B9h (185) (NetWare4) NoWait specified and child still running
 BAh (186) (NetWare4) invalid flag number
 BBh (187) (NetWare4) semaphore does not exist
 BCh (188) (NetWare4) invalid starting code segment
 BDh (189) (NetWare4) invalid stack segment
 BEh (190) (NetWare4) invalid module type (DLL can not be used as application)
 BFh (191) (NetWare4) invalid EXE signature
 C0h (192) (NetWare4) EXE marked invalid
 C1h (193) (NetWare4) bad EXE format (e.g. DOS-mode program)
 C2h (194) (NetWare4) iterated data exceeds 64K
 C3h (195) (NetWare4) invalid minimum allocation size
 C4h (196) (NetWare4) dynamic link from invalid Ring
 C5h (197) (NetWare4) IOPL not enabled
 C6h (198) (NetWare4) invalid segment descriptor privilege level
 C7h (199) (NetWare4) automatic data segment exceeds 64K
 C8h (200) (NetWare4) Ring2 segment must be moveable
 C9h (201) (NetWare4) relocation chain exceeds segment limit
 CAh (202) (NetWare4) infinite loop in relocation chain
 CBh (203) (NetWare4) environment variable not found
 CCh (204) (NetWare4) not current country
 CDh (205) (NetWare4) no signal sent
 CEh (206) (NetWare4) file name not 8.3
 CFh (207) (NetWare4) Ring2 stack in use
 D0h (208) (NetWare4) meta expansion is too long
 D1h (209) (NetWare4) invalid signal number
 D2h (210) (NetWare4) inactive thread
 D3h (211) (NetWare4) file system information not available
 D4h (212) (NetWare4) locked error
 D5h (213) (NetWare4) attempted to execute non-family API call in DOS mode
 D6h (214) (NetWare4) too many modules
 D7h (215) (NetWare4) nesting not allowed
 E6h (230) (NetWare4) non-existent pipe, or bad operation
 E7h (231) (NetWare4) pipe is busy
 E8h (232) (NetWare4) no data available for nonblocking read
 E9h (233) (NetWare4) pipe disconnected by server
 EAh (234) (NetWare4) more data available
 FFh (255) (NetWare4) invalid drive
SeeAlso: #1022,#1023,#1024,#1295

Format of media ID structure:
Offset    Size    Description    (Table 1021)
 00h 12 BYTEs    ASCIZ volume label of required disk
 0Ch    DWORD    serial number (DOS 4.0+)

(Table 1022)
Values for DOS Error Class:
 01h    out of resource (storage space or I/O channels)
 02h    temporary situation (file or record lock)
 03h    authorization (denied access)
 04h    internal (system software bug)
 05h    hardware failure
 06h    system failure (configuration file missing or incorrect)
 07h    application program error
 08h    not found
 09h    bad format
 0Ah    locked
 0Bh    media error
 0Ch    already exists
 0Dh    unknown
SeeAlso: #1020,#1023,#1024

(Table 1023)
Values for DOS Suggested Action:
 01h    retry
 02h    delayed retry
 03h    prompt user to reenter input
 04h    abort after cleanup
 05h    immediate abort
 06h    ignore
 07h    retry after user intervention
SeeAlso: #1020,#1022,#1024

(Table 1024)
Values for DOS Error Locus:
 01h    unknown or not appropriate
 02h    block device (disk error)
 03h    network related
 04h    serial device (timeout)
 05h    memory related
SeeAlso: #1020,#1022,#1023
--------D-2159--BX0001-----------------------
INT 21 - European MS-DOS 4.0 - GET HARD ERROR INFORMATION
    AH = 59h
    BX = 0001h
Return: ES:DI -> hard error information packet (see #1025) for most recent
        hard (critical) error
SeeAlso: AH=59h/BX=0000h,AH=95h,INT 24

Format of European MS-DOS 4.0 hard error information packet:
Offset    Size    Description    (Table 1025)
 00h    WORD    contents of AX at system entry
 02h    WORD    Process ID which encountered error
 04h    WORD    contents of AX at time of error
 06h    BYTE    error type
        00h physical I/O error
        01h disk change request
        02h file sharing violation
        03h FCB problem
        04h file locking violation
        05h bad FAT
        06h network detected error
 07h    BYTE    INT 24 error code
 08h    WORD    extended error code (see #1020)
 0Ah    DWORD    pointer to associated device
--------D-215A-------------------------------
INT 21 - DOS 3.0+ - CREATE TEMPORARY FILE
    AH = 5Ah
    CX = file attribute (see #0765 at AX=4301h)
    DS:DX -> ASCIZ path ending with a '\' + 13 zero bytes to receive the
        generated filename
Return: CF clear if successful
        AX = file handle opened for read/write in compatibility mode
        DS:DX pathname extended with generated name for temporary file
    CF set on error
        AX = error code (03h,04h,05h) (see #1020)
Desc:    creates a file with a unique name which must be explicitly deleted
BUGS:    COMPAQ DOS 3.31 hangs if the pathname is at XXXXh:0000h; it apparently
      wraps around to the end of the segment
    MS-DOS 5.00 revisions A and B and PC-DOS 5.00 revision A reportedly
      hang the system if the specified path is the root directory and the
      root directory is full (no free directory entries)
    Mark Incley <[e-mail]> reports that this function
      hangs in DOS 6.2x if the name includes two consecutive path
      separators (e.g. C:\\ )
Notes:    under the FlashTek X-32 DOS extender, the path pointer is in DS:EDX
    MS-DOS 3.0-4.0 and DR-DOS 3.4-5.0 generate the filename as a sequence
      of hex digits based on the current date and time; MS-DOS 6+,
      DR-DOS 6, and Novell DOS 7 use letters A-P in place of hex digits
SeeAlso: AH=3Ch,AH=5Bh
--------D-215B-------------------------------
INT 21 - DOS 3.0+ - CREATE NEW FILE
    AH = 5Bh
    CX = file attribute (see #0765 at AX=4301h)
    DS:DX -> ASCIZ filename
Return: CF clear if successful
        AX = file handle opened for read/write in compatibility mode
    CF set on error
        AX = error code (03h,04h,05h,50h) (see #1020)
Notes:    unlike AH=3Ch, this function will fail if the specified file exists
      rather than truncating it; this permits its use in creating semaphore
      files because it is an atomic "test and set" operation
    under the FlashTek X-32 DOS extender, the filename pointer is in DS:EDX
SeeAlso: AH=3Ch,AH=5Ah
--------D-215C-------------------------------
INT 21 - DOS 3.0+ - "FLOCK" - RECORD LOCKING
    AH = 5Ch
    AL = subfunction
        00h lock region of file
        01h unlock region of file
    BX = file handle
    CX:DX = start offset of region within file
    SI:DI = length of region in bytes
Return: CF clear if successful
    CF set on error
        AX = error code (01h,06h,21h,24h) (see #1020)
Notes:    error returned unless SHARE or network installed
    an unlock call must specify the same region as some prior lock call
    locked regions become entirely inaccessible to other processes
    duplicate handles created with AH=45h or AH=46h inherit locks, but
      handles inherited by child processes (see AH=4Bh) do not
    under DR DOS 3.41 and 5.0, if a process opens a file without the no-
      inherit flag and then starts a child, any locks set by the parent
      are ignored, and the child will only get an error if it tries to
      lock an area previously locked by the parent process
SeeAlso: AX=440Bh,AH=BCh,AH=BEh,INT 2F/AX=110Ah,INT 2F/AX=110Bh
--------D-215D00-----------------------------
INT 21 U - DOS 3.1+ internal - SERVER FUNCTION CALL
    AX = 5D00h
    DS:DX -> DOS parameter list (see #1026)
    DPL contains all register values for a call to INT 21h
Return: as appropriate for function being called
Notes:    does not check AH.  Out of range values will crash the system
    executes using specified computer ID and process ID
    sharing delay loops skipped
    a special sharing mode is enabled to handle FCBs opened across network
    wildcards are enabled for DELETE (AH=41h) and RENAME (AH=56h) under
      MS-DOS; under DR DOS 3.41, wildcards corrupt the filesystem; and
      under DR DOS 5.0-6.0, the call returns error code 03h due to improper
      support for the server function call (refer to BUGS: section below)
    an extra file attribute parameter is enabled for OPEN (AH=3Dh),
      DELETE (AH=41h), and RENAME (AH=56h)
    functions which take filenames require canonical names (as returned
      by AH=60h); this is apparently to prevent multi-hop file forwarding
BUGS:    the OS/2 2.0 DOS Boot Session incorrectly maps DOS drive letters,
      seemingly ignoring HPFS drives
    DR DOS 5.0-6.0 merely recursively call INT 21 after loading the
      registers from the DPL, leading to problems for peer-to-peer
      networks
SeeAlso: AH=3Dh,AH=41h,AH=56h,AH=60h

Format of DOS parameter list:
Offset    Size    Description    (Table 1026)
 00h    WORD    AX
 02h    WORD    BX
 04h    WORD    CX
 06h    WORD    DX
 08h    WORD    SI
 0Ah    WORD    DI
 0Ch    WORD    DS
 0Eh    WORD    ES
 10h    WORD    reserved (0)
 12h    WORD    computer ID (0 = current system)
 14h    WORD    process ID (PSP segment on specified computer)
Note:    under Windows Enhanced mode, the computer ID is normally the virtual
      machine ID (see INT 2F/AX=1683h), though this can reportedly be
      changed by setting UniqueDOSPSP= in SYSTEM.INI
--------D-215D01-----------------------------
INT 21 U - DOS 3.1+ internal - COMMIT ALL FILES FOR SPECIFIED COMPUTER/PROCESS
    AX = 5D01h
    DS:DX -> DOS parameter list (see #1026), only computer ID and
          process ID fields used
Return: CF set on error
        AX = error code (see #1020)
    CF clear if successful
Notes:    flushes buffers and updates directory entries for each file which has
      been written to; if remote file, calls INT 2F/AX=1107h
    the computer ID and process ID are stored but ignored under DOS 3.3
    not supported by DR DOS 3.41 and 5.0; returns error code 01h
SeeAlso: AH=0Dh,AH=68h,INT 2F/AX=1107h
--------D-215D02-----------------------------
INT 21 U - DOS 3.1+ internal - SHARE.EXE - CLOSE FILE BY NAME
    AX = 5D02h
    DS:DX -> DOS parameter list (see #1026), only fields DX, DS,
          computer ID, and process ID used
    DPL's DS:DX -> ASCIZ name of file to close
Return: CF set on error
        AX = error code (see #1020)
    CF clear if successful
Notes:    error unless SHARE is loaded (calls [SysFileTable-28h])
      (see #0977 at AH=52h)
    name must be canonical fully-qualified, such as returned by AH=60h
    not supported by DR DOS 3.41 and 5.0; returns error code 01h
    not supported by Novell DOS 7
SeeAlso: AX=5D03h,AX=5D04h,AH=3Eh,AH=60h
--------D-215D03-----------------------------
INT 21 U - DOS 3.1+ internal - SHARE.EXE - CLOSE ALL FILES FOR GIVEN COMPUTER
    AX = 5D03h
    DS:DX -> DOS parameter list (see #1026), only computer ID used
Return: CF set on error
        AX = error code (see #1020)
    CF clear if successful
Notes:    error unless SHARE is loaded (calls [SysFileTable-30h])
      (see #0977 at AH=52h)
    not supported by DR DOS 3.41 and 5.0; returns error code 01h
    not supported by Novell DOS 7
SeeAlso: AX=5D02h,AX=5D04h
--------D-215D04-----------------------------
INT 21 U - DOS 3.1+ internal - SHARE.EXE - CLOSE ALL FILES FOR GIVEN PROCESS
    AX = 5D04h
    DS:DX -> DOS parameter list (see #1026), only computer ID and
          process ID fields used
Return: CF set on error
        AX = error code (see #1020)
    CF clear if successful
Notes:    error unless SHARE is loaded (calls [SysFileTable-2Ch])
       (see #0977 at AH=52h)
    not supported by DR DOS 3.41 and 5.0; returns error code 01h
    not supported by Novell DOS 7
SeeAlso: AX=5D02h,AX=5D03h,INT 2F/AX=111Dh
--------D-215D05-----------------------------
INT 21 U - DOS 3.1+ internal - SHARE.EXE - GET OPEN FILE LIST ENTRY
    AX = 5D05h
    DS:DX -> DOS parameter list (see #1026)
    DPL's BX = index of sharing record (see #0978 at AH=52h)
    DPL's CX = index of SFT in sharing record's SFT list
Return: CF clear if successful
        ES:DI -> ASCIZ filename
        BX = network machine number of SFT's owner
        CX = number of locks held by SFT's owner
    CF set if either index out of range
        AX = 0012h (no more files)
Notes:    error unless SHARE is loaded (calls [SysFileTable-18h])
      (see #0977 at AH=52h)
    names are always canonical fully-qualified, such as returned by AH=60h
    not supported by DR DOS 3.41 and 5.0 and Novell DOS 7, but does not
      return an error, instead destroying AX
SeeAlso: AH=5Ch,AH=60h
--------D-215D06-----------------------------
INT 21 U - DOS 3.0+ internal - GET ADDRESS OF DOS SWAPPABLE DATA AREA
    AX = 5D06h
Return: CF set on error
       AX = error code (see #1020)
    CF clear if successful
        DS:SI -> nonreentrant data area (includes all three DOS stacks)
        (critical error flag is first byte) (see #1027)
        CX = size in bytes of area which must be swapped while in DOS
        DX = size in bytes of area which must always be swapped
Notes:    the Critical Error flag is used in conjunction with the InDOS flag
      (see AH=34h) to determine when it is safe to enter DOS from a TSR
    setting CritErr flag allows use of functions 50h/51h from INT 28h under
      DOS 2.x by forcing use of correct stack
    swapping the data area allows reentering DOS unless DOS is in a
      critical section delimited by INT 2A/AH=80h and INT 2A/AH=81h,82h
    under DOS 4.0, AX=5D0Bh should be used instead of this function
    SHARE and other DOS utilities consult the byte at offset 04h in the
      DOS data segment (see INT 2F/AX=1203h) to determine the SDA format
      in use: 00h = DOS 3.x, 01h = DOS 4.0-6.0, other = error.
    DR DOS 3.41+ supports this function, but the SDA format beyond the
      first 18h bytes is completely different from MS-DOS
SeeAlso: AX=5D0Bh,INT 2A/AH=80h,INT 2A/AH=81h,INT 2A/AH=82h

Format of DOS 3.10-3.30 Swappable Data Area:
Offset    Size    Description    (Table 1027)
 -34    BYTE    (DOS 3.10+) printer echo flag (00h off, FFh active)
 -31    BYTE    (DOS 3.30) current switch character
 -30    BYTE    current memory allocation strategy (see AH=58h)
 -28    BYTE    (DOS 3.30) incremented on each INT 21/AX=5E01h call
 -27 16 BYTEs    (DOS 3.30) machine name set by INT 21/AX=5E01h
 -11  5 WORDs    zero-terminated list of offsets which need to be patched to
          enable critical-section calls (see INT 2A/AH=80h)
 -1    BYTE    unused padding
---start of actual SDA---
 00h    BYTE    critical error flag ("ErrorMode")
 01h    BYTE    InDOS flag (count of active INT 21 calls)
 02h    BYTE    drive on which current critical error occurred, or FFh
        (DR DOS sets to drive number during INT 24, 00h otherwise)
 03h    BYTE    locus of last error
 04h    WORD    extended error code of last error
 06h    BYTE    suggested action for last error
 07h    BYTE    class of last error
 08h    DWORD    ES:DI pointer for last error
 0Ch    DWORD    current DTA (Disk Transfer Address)
        note: may point into SDA during the DOS EXEC function
          (see AH=4Bh), so programs which swap the SDA must be
          prepared to move the DTA to a private buffer if they
          might be invoked during an EXEC
 10h    WORD    current PSP
 12h    WORD    stores SP across an INT 23
 14h    WORD    return code from last process termination (zerod after reading
          with AH=4Dh)
 16h    BYTE    current drive
 17h    BYTE    extended break flag
---remainder need only be swapped if in DOS---
 18h    WORD    value of AX on call to INT 21
 1Ah    WORD    PSP segment for sharing/network
 1Ch    WORD    network machine number for sharing/network (0000h = us)
 1Eh    WORD    first usable memory block found when allocating memory
 20h    WORD    best usable memory block found when allocating memory
 22h    WORD    last usable memory block found when allocating memory
 24h    WORD    memory size in paragraphs (used only during initialization)
 26h    WORD    last entry checked during directory search
 28h    BYTE    flag: INT 24 returned Fail
 29h    BYTE    flags: allowable INT 24 actions (passed to INT 24 in AH)
 2Ah    BYTE    directory flag (00h directory, 01h file)
 2Bh    BYTE    flag: FFh if Ctrl-Break termination, 00h otherwise
 2Ch    BYTE    flag: allow embedded blanks in FCB
 2Dh    BYTE    padding (unused)
 2Eh    BYTE    day of month
 2Fh    BYTE    month
 30h    WORD    year - 1980
 32h    WORD    number of days since 1-1-1980
 34h    BYTE    day of week (0 = Sunday)
 35h    BYTE    flag: console swapped during read from device
 36h    BYTE    flag: safe to call INT 28 if nonzero
 37h    BYTE    flag: if nonzero, INT 24 Abort turned into INT 24 Fail
        (set only during process termination)
 38h 26 BYTEs    device driver request header (see #1931 at INT 2F/AX=0802h)
 52h    DWORD    pointer to device driver entry point (used in calling driver)
 56h 22 BYTEs    device driver request header for I/O calls
 6Ch 14 BYTEs    device driver request header for disk status check
 7Ah    DWORD    pointer to device I/O buffer???
 7Eh    WORD    ???
 80h    WORD    ???
 82h    BYTE    type of PSP copy (00h=simple for INT 21/AH=26h, FFh=make child)
 83h    BYTE    padding (unused)
 84h  3 BYTEs    24-bit user number (see AH=30h)
 87h    BYTE    OEM number (see #0741 at AH=30h)
 88h    WORD    offset to error code conversion table for INT 25/INT 26
 8Ah  6 BYTEs    CLOCK$ transfer record (see #1028)
 90h    BYTE    device I/O buffer for single-byte I/O functions
 91h    BYTE    padding??? (unused)
 92h 128 BYTEs    buffer for filename
112h 128 BYTEs    buffer for filename
192h 21 BYTEs    findfirst/findnext search data block (see #0967 at AH=4Eh)
1A7h 32 BYTEs    directory entry for found file (see #0700 at AH=11h)
1C7h 81 BYTEs    copy of current directory structure for drive being accessed
218h 11 BYTEs    FCB-format filename for device name comparison
223h    BYTE    terminating NUL for above filename
224h 11 BYTEs    wildcard destination specification for rename (FCB format)
22Fh    BYTE    terminating NUL for above spec
230h    BYTE    ???
231h    WORD    destination file/directory starting sector
233h  5 BYTEs    ???
238h    BYTE    extended FCB file attribute
239h    BYTE    type of FCB (00h regular, FFh extended)
23Ah    BYTE    directory search attributes
23Bh    BYTE    file open/access mode
23Ch    BYTE    file found/delete flag
        bit 0: file found
        bit 4: file deleted
23Dh    BYTE    flag: device name found on rename, or file not found
23Eh    BYTE    splice flag (file name and directory name together)
23Fh    BYTE    flag indicating how DOS function was invoked
        (00h = direct INT 20/INT 21, FFh = server call AX=5D00h)
240h    BYTE    sector position within cluster
241h    BYTE    flag: translate sector/cluster (00h no, 01h yes)
242h    BYTE    flag: 00h if read, 01h if write
243h    BYTE    current working drive number
244h    BYTE    cluster factor
245h    BYTE    flag: cluster split mode
246h    BYTE    line edit (AH=0Ah) insert mode flag (nonzero = on)
247h    BYTE    canonicalized filename referred to existing file/dir if FFh
248h    BYTE    volume ID flag
249h    BYTE    type of process termination (00h-03h) (see AH=4Dh)
24Ah    BYTE    file create flag (00h = no, search only)
24Bh    BYTE    value with which to replace first byte of deleted file's name
          (normally E5h, but 00h as described under INT 21/AH=13h)
24Ch    DWORD    pointer to Drive Parameter Block for critical error invocation
        temp: used during process termination
250h    DWORD    pointer to stack frame containing user registers on INT 21
254h    WORD    stores SP across INT 24
256h    DWORD    pointer to DOS Drive Parameter Block for ???
25Ah    WORD    saving partial cluster number
25Ch    WORD    temp: sector of work current cluster
25Eh    WORD    high part of cluster number (only low byte referenced)
260h    WORD    ??? temp
262h    BYTE    Media ID byte returned by AH=1Bh,1Ch
263h    BYTE    padding (unused)
264h    DWORD    pointer to device header when filename is character device
268h    DWORD    pointer to current SFT
26Ch    DWORD    pointer to current directory structure for drive being accessed
270h    DWORD    pointer to caller's FCB
274h    WORD    number of SFT to which file being opened will refer
276h    WORD    temporary storage for file handle
278h    DWORD    pointer to a JFT entry in process handle table
          (see #0725 at AH=26h)
27Ch    WORD    offset in DOS DS of first filename argument
27Eh    WORD    offset in DOS DS of second filename argument
280h    WORD    offset of last component in pathname or FFFFh
282h    WORD    offset of transfer address to add
284h    WORD    last relative cluster within file being accessed
286h    WORD    temp: absolute cluster number being accessed
288h    WORD    directory sector number
28Ah    WORD    ??? current cluster number
28Ch    WORD    current relative sector number within file
28Eh    WORD    current sector number
290h    WORD    current byte offset within sector
292h    DWORD    current offset in file
296h    DWORD    temp: file byte count
29Ah    WORD    temp: file byte count
29Ch    WORD    free file cluster entry
29Eh    WORD    last file cluster entry
2A0h    WORD    next file cluster number
2A2h    DWORD    number of bytes appended to file
2A6h    DWORD    pointer to current work disk buffer
2AAh    DWORD    pointer to working SFT
2AEh    WORD    used by INT 21 dispatcher to store caller's BX
2B0h    WORD    used by INT 21 dispatcher to store caller's DS
2B2h    WORD    temporary storage while saving/restoring caller's registers
2B4h    DWORD    pointer to prev call frame (offset 250h) if INT 21 reentered
        also switched to for duration of INT 24
2B8h 21 BYTEs    FindFirst search data for source file(s) of a rename operation
        (see #0967 at AH=4Eh)
2CDh 32 BYTEs    directory entry for file being renamed (see #0700 at AH=11h)
2EDh 331 BYTEs    critical error stack
   403h     35 BYTEs scratch SFT
438h 384 BYTEs    disk stack (functions greater than 0Ch, INT 25,INT 26)
5B8h 384 BYTEs    character I/O stack (functions 01h through 0Ch)
---DOS 3.2,3.3x only---
738h    BYTE    device driver lookahead flag (usually printer)
        (see AH=64h"DOS 3.2+")
739h    BYTE    volume change flag
73Ah    BYTE    flag: virtual open
73Bh    BYTE    ???
SeeAlso: #1030

Format of CLOCK$ transfer record:
Offset    Size    Description    (Table 1028)
 00h    WORD    number of days since 1-Jan-1980
 02h    BYTE    minutes
 03h    BYTE    hours
 04h    BYTE    hundredths of second
 05h    BYTE    seconds
--------D-215D07-----------------------------
INT 21 U - DOS 3.1+ network - GET REDIRECTED PRINTER MODE
    AX = 5D07h
Return: DL = mode
        00h redirected output is combined
        01h redirected output in separate print jobs
SeeAlso: AX=5D08h,AX=5D09h,INT 2F/AX=1125h
--------D-215D08-----------------------------
INT 21 U - DOS 3.1+ network - SET REDIRECTED PRINTER MODE
    AX = 5D08h
    DL = mode
        00h redirected output is combined
        01h redirected output placed in separate jobs, start new print job
        now
SeeAlso: AX=5D07h,AX=5D09h,INT 2F/AX=1125h
--------D-215D09-----------------------------
INT 21 U - DOS 3.1+ network - FLUSH REDIRECTED PRINTER OUTPUT
    AX = 5D09h
Notes:    forces redirected printer output to be printed, and starts a new print
      job
    this function is also supported by 10Net, which calls it Terminate All
      Spool Jobs, and does not flush if in "combine" mode
SeeAlso: AX=5D07h,AX=5D08h,INT 2F/AX=1125h
--------D-215D0A-----------------------------
INT 21 - DOS 3.1+ - SET EXTENDED ERROR INFORMATION
    AX = 5D0Ah
    DS:DX -> 11-word DOS parameter list (see #1026)
Return: nothing.  next call to AH=59h will return values from fields AX,BX,CX,
      DX,DI, and ES in corresponding registers
Notes:    documented for DOS 5+, but undocumented in earlier versions
    the MS-DOS Programmer's Reference incorrectly states that this call was
      introduced in DOS 4, and fails to mention that the ERROR structure
      passed to this function is a DOS parameter list.
BUGS:    DR DOS 3.41 and 5.0 read the value for ES from the DS field of the
      DPL; fortunately, MS-DOS ignores the DS field, allowing a generic
      routine which sets both DS and ES fields to the same value
    Novell DOS 7 does not save the pointer, which is always reported as
      0000h:0000h by AH=59h
SeeAlso: AH=59h/BX=0000h
--------D-215D0B-----------------------------
INT 21 OU - DOS 4.x only internal - GET DOS SWAPPABLE DATA AREAS
    AX = 5D0Bh
Return: CF set on error
        AX = error code (see #1020)
    CF clear if successful
        DS:SI -> swappable data area list (see #1029)
Notes:    copying and restoring the swappable data areas allows DOS to be
      reentered unless it is in a critical section delimited by calls to
      INT 2A/AH=80h and INT 2A/AH=81h,82h
    SHARE and other DOS utilities consult the byte at offset 04h in the
      DOS data segment (see INT 2F/AX=1203h) to determine the SDA format
      in use: 00h = DOS 3.x, 01h = DOS 4.0-6.0, other = error.
    DOS 5+ use the SDA format listed below, but revert back to the DOS 3.x
      call for finding the SDA (see #1027)
SeeAlso: AX=5D06h,INT 2A/AH=80h,INT 2A/AH=81h,INT 2A/AH=82h,INT 2F/AX=1203h

Format of DOS 4.x swappable data area list:
Offset    Size    Description    (Table 1029)
 00h    WORD    count of data areas
 02h  N BYTEs    "count" copies of data area record
        Offset    Size    Description
         00h    DWORD    address
         04h    WORD    length and type
                bit 15 set if swap always, clear if swap in DOS
                bits 14-0: length in bytes
SeeAlso: #1030

Format of DOS 4.0-6.0 swappable data area:
Offset    Size    Description    (Table 1030)
 -34    BYTE    printer echo flag (00h off, FFh active)
 -31    BYTE    current switch character (ignored by DOS 5+)
 -30    BYTE    current memory allocation strategy (see AH=58h)
 -28    BYTE    incremented on each INT 21/AX=5E01h call
 -27 16 BYTEs    machine name set by INT 21/AX=5E01h
 -11  5 WORDs    zero-terminated list of offsets which need to be patched to
          enable critical-section calls (see INT 2A/AH=80h)
        (all offsets are 0D0Ch, but this list is still present for
          DOS 3.x compatibility)
 -1    BYTE    unused padding
---start of actual SDA---
 00h    BYTE    critical error flag ("ErrorMode")
 01h    BYTE    InDOS flag (count of active INT 21 calls)
 02h    BYTE    drive on which current critical error occurred or FFh
 03h    BYTE    locus of last error
 04h    WORD    extended error code of last error
 06h    BYTE    suggested action for last error
 07h    BYTE    class of last error
 08h    DWORD    ES:DI pointer for last error
 0Ch    DWORD    current DTA (Disk Transfer Address)
        note: may point into SDA during the DOS EXEC function
          (see AH=4Bh), so programs which swap the SDA must be
          prepared to move the DTA to a private buffer if they
          might be invoked during an EXEC
 10h    WORD    current PSP
 12h    WORD    stores SP across an INT 23
 14h    WORD    return code from last process termination (zerod after reading
          with AH=4Dh)
 16h    BYTE    current drive
 17h    BYTE    extended break flag
 18h    BYTE    flag: code page switching
 19h    BYTE    flag: copy of previous byte in case of INT 24 Abort
---remainder need only be swapped if in DOS---
 1Ah    WORD    value of AX on call to INT 21
 1Ch    WORD    PSP segment for sharing/network
 1Eh    WORD    network machine number for sharing/network (0000h = us)
 20h    WORD    first usable memory block found when allocating memory
 22h    WORD    best usable memory block found when allocating memory
 24h    WORD    last usable memory block found when allocating memory
 26h    WORD    memory size in paragraphs (used only during initialization)
 28h    WORD    last entry checked during directory search
 2Ah    BYTE    flag: nonzero if INT 24 Fail
 2Bh    BYTE    flags: allowable INT 24 responses (passed to INT 24 in AH)
 2Ch    BYTE    flag: do not set directory if nonzero
 2Dh    BYTE    flag: program aborted by ^C
 2Eh    BYTE    flag: allow embedded blanks in FCB
        may also allow use of "*" wildcard in FCBs
 2Fh    BYTE    padding (unused)
 30h    BYTE    day of month
 31h    BYTE    month
 32h    WORD    year - 1980
 34h    WORD    number of days since 1-1-1980
 36h    BYTE    day of week (0 = Sunday)
 37h    BYTE    flag: console swapped during read from device
 38h    BYTE    flag: safe to call INT 28 if nonzero
 39h    BYTE    flag: abort currently in progress, turn INT 24 Abort into Fail
 3Ah 30 BYTEs    device driver request header (see #1931 at INT 2F/AX=0802h) for
          device calls
 58h    DWORD    pointer to device driver entry point (used in calling driver)
 5Ch 22 BYTEs    device driver request header for I/O calls
 72h 14 BYTEs    device driver request header for disk status check
 80h    DWORD    pointer to device I/O buffer
 84h    WORD    ???
 86h    WORD    ??? (0)
 88h    BYTE    type of PSP copy (00h=simple for INT 21/AH=26h, FFh=make child)
 89h    DWORD    start offset of file region to lock/unlock
 8Dh    DWORD    length of file region to lock/unlock
 91h    BYTE    padding (unused)
 92h  3 BYTEs    24-bit user number (see AH=30h)
 95h    BYTE    OEM number (see #0741 at AH=30h)
 96h  6 BYTEs    CLOCK$ transfer record (see #1028 at AX=5D06h)
 9Ch    BYTE    device I/O buffer for single-byte I/O functions
 9Dh    BYTE    padding???
 9Eh 128 BYTEs    buffer for filename
11Eh 128 BYTEs    buffer for filename
19Eh 21 BYTEs    findfirst/findnext search data block (see #0967 at AH=4Eh)
1B3h 32 BYTEs    directory entry for found file (see #0741 at AH=11h)
1D3h 88 BYTEs    copy of current directory structure for drive being accessed
22Bh 11 BYTEs    FCB-format filename for device name comparison
236h    BYTE    terminating NUL for above filename
237h 11 BYTEs    wildcard destination specification for rename (FCB format)
242h    BYTE    terminating NUL for above filespec
243h    BYTE    ???
244h    WORD    ???
246h  5 BYTEs    ???
24Bh    BYTE    extended FCB file attributes
24Ch    BYTE    type of FCB (00h regular, FFh extended)
24Dh    BYTE    directory search attributes
24Eh    BYTE    file open/access mode
24Fh    BYTE    ??? flag bits
        reportedly 00h when deleting a file under MSDOS 5.0
250h    BYTE    flag: device name found on rename, or file not found
251h    BYTE    splice flag??? (file name and directory name together)
252h    BYTE    flag indicating how DOS function was invoked
        (00h = direct INT 20/INT 21, FFh = server call AX=5D00h)
253h    BYTE    sector position within cluster
254h    BYTE    ??? (flag: translate sector/cluster)
255h    BYTE    ??? (flag: 00h if read, 01h if write)
256h    BYTE    current working drive number
257h    BYTE    cluster factor
258h    BYTE    ???
259h    BYTE    line edit (AH=0Ah) insert mode flag (nonzero = on)
25Ah    BYTE    canonicalized filename referred to existing file/dir if FFh
25Bh    BYTE    volume ID flag
25Ch    BYTE    type of process termination (00h-03h) (see AH=4Dh)
25Dh    BYTE    ???
25Eh    BYTE    ??? file create flag (00h = no, search only)
25Fh    BYTE    ??? (value for deleted file's first byte)
260h    DWORD    pointer to Drive Parameter Block for critical error invocation
264h    DWORD    pointer to stack frame containing user registers on INT 21
268h    WORD    stores SP across INT 24
26Ah    DWORD    pointer to DOS Drive Parameter Block for ???
26Eh    WORD    segment of disk buffer
270h    WORD    ??? (saving partial cluster number)
272h    WORD    ??? (temp: sector of work current cluster)
274h    WORD    ??? (high part of cluster number)
276h    WORD    ??? (temp)
278h    BYTE    Media ID byte returned by AH=1Bh,1Ch
279h    BYTE    ??? (doesn't seem to be referenced)
27Ah    DWORD    pointer to device header if filename is character device
27Eh    DWORD    pointer to current SFT
282h    DWORD    pointer to current directory structure for drive being accessed
286h    DWORD    pointer to caller's FCB
28Ah    WORD    SFT index to which file being opened will refer
28Ch    WORD    temporary storage for file handle
28Eh    DWORD    pointer to a JFT entry in process handle table
          (see #0725 at AH=26h)
292h    WORD    offset in DOS DS of first filename argument
294h    WORD    offset in DOS DS of second filename argument
296h    WORD    ??? (offset of last component in pathname or FFFFh)
298h    WORD    offset of transfer address to add
29Ah    WORD    last relative cluster within file being accessed
29Ch    WORD    temp: absolute cluster number being accessed
29Eh    WORD    directory sector number
2A0h    WORD    ???
2A2h    WORD    ??? directory cluster number
2A4h    DWORD    current relative sector number within file
2A8h    DWORD    ??? (current sector number)
2ACh    WORD    ??? (current byte offset within sector)
2AEh    DWORD    current offset in file
2B2h    WORD    ???
2B4h    WORD    bytes in partial sector
2B6h    WORD    number of sectors
2B8h    WORD    ??? (free file cluster entry)
2BAh    WORD    ??? (last file cluster entry)
2BCh    WORD    ??? (next file cluster number)
2BEh    DWORD    number of bytes appended to file
2C2h    DWORD    pointer to current work disk buffer
2C6h    DWORD    pointer to working SFT
2CAh    WORD    used by INT 21 dispatcher to store caller's BX
2CCh    WORD    used by INT 21 dispatcher to store caller's DS
2CEh    WORD    temporary storage while saving/restoring caller's registers
2D0h    DWORD    pointer to prev call frame (offset 264h) if INT 21 reentered
        also switched to for duration of INT 24
2D4h    WORD    open mode/action for INT 21/AX=6C00h
2D6h    BYTE    ??? (set to 00h by INT 21h dispatcher, 02h when a read is
          performed, and 01h or 03h by INT 21/AX=6C00h)
2D7h    WORD    ??? apparently unused
2D9h    DWORD    stored ES:DI for AX=6C00h
2DDh    WORD    extended file open action code (see #1112 at AX=6C00h)
2DFh    WORD    extended file open attributes (see #1111 at AX=6C00h)
2E1h    WORD    extended file open file mode (see AX=6C00h)
2E3h    DWORD    pointer to filename to open (see AX=6C00h)
2E7h    WORD    ??? temp DX storage or 0000h or temp data buffer size from
          disk buffer
2E9h    WORD    ???
2EBh    BYTE    ???
2ECh    WORD    stores DS during call to [List-of-Lists + 37h]
2EEh    WORD    ???
2F0h    BYTE    ???
2F1h    WORD    ??? bit flags
2F3h    DWORD    pointer to user-supplied filename
2F7h    DWORD    pointer to ???
2FBh    WORD    stores SS during call to [List-of-Lists + 37h]
2FDh    WORD    stores SP during call to [List-of-Lists + 37h]
2FFh    BYTE    flag, nonzero if stack switched in calling [List-of-Lists+37h]
300h 21 BYTEs    FindFirst search data for source file(s) of a rename operation
        (see #0967 at AH=4Eh)
315h 32 BYTEs    directory entry for file being renamed (see #0700 at AH=11h)
335h 331 BYTEs    critical error stack
480h 384 BYTEs    disk stack (functions greater than 0Ch, INT 25,INT 26)
600h 384 BYTEs    character I/O stack (functions 01h through 0Ch)
780h    BYTE    device driver lookahead flag (usually printer)
        (see AH=64h"DOS 3.2+")
781h    BYTE    volume change flag
782h    BYTE    flag: virtual open
783h    BYTE    ???
784h    WORD    ???
786h    WORD    ???
788h    WORD    ???
78Ah    WORD    ???
SeeAlso: #1027,#1029
--------D-215E00-----------------------------
INT 21 - DOS 3.1+ network - GET MACHINE NAME
    AX = 5E00h
    DS:DX -> 16-byte buffer for ASCII machine name
Return: CF clear if successful
        CH = validity
        00h name invalid
        nonzero valid
            CL = NetBIOS number for machine name
            DS:DX buffer filled with blank-paded name
    CF set on error
        AX = error code (01h) (see #1020 at AH=59h)
Note:    supported by OS/2 v1.3+ compatibility box, PC-NFS
SeeAlso: AX=5E01h
--------N-215E00-----------------------------
INT 21 - 10NET v5.0 - GET MACHINE NAME
    AX = 5E00h
Return: CL = redirector's NetBIOS name number
    ES:DI -> network node ID
SeeAlso: AX=5E01h"10NET"
--------D-215E01CH00-------------------------
INT 21 - DOS 3.1+ network - SET MACHINE NAME
    AX = 5E01h
    CH = 00h undefine name (make it invalid)
       <> 0     define name
    CL = name number
    DS:DX -> 15-character blank-padded ASCIZ name
SeeAlso: AX=5E00h
--------N-215E01-----------------------------
INT 21 - 10NET v5.0 - GET LOCAL 10NET CONFIGURATION TABLE
    AX = 5E01h
    CX = length of buffer
    DS:DX -> buffer for 10Net configuration table (see #1031)
Return: DS:DX buffer filled
SeeAlso: AX=5E00h"10NET",INT 6F/AH=02h,INT 6F/AH=03h

Format of 10Net Configuration Table:
Offset    Size    Description    (Table 1031)
 00h  8 BYTEs    user name
 08h 15 BYTEs    node ID
 17h  3 BYTEs    unique portion of Ethernet address
 1Ah    BYTE    Who group number
 1Bh    WORD    services mask (see #1033)
 1Dh    DWORD    serial number
 21h    BYTE    maximum concurrent users with same serial number allowed on net
 22h    BYTE    chat mask (see #1034)
 23h    BYTE    internal system bits (see #1035)
 24h  9 BYTEs    version number in format MM.mm.xxx
 2Dh    BYTE    flag: 01h if machine is a PS/2
 2Eh    BYTE    flag: 03h if 80386
 2Fh    BYTE    spool termination mode: 01h concatenate, 02h truncate
        (see AX=5D09h)
 30h    WORD    autospool timeout in clock ticks
 32h    WORD    monitor timeout in clock ticks
 34h    WORD    unused
 36h    WORD    chat timeout in clock ticks
 38h    WORD    netBIOS session timeout in half-seconds
 3Ah    WORD    datagram send timeout in seconds
 3Ch    WORD    keyboard value for initiating chat mode
 3Eh    WORD    Who timeout in clock ticks
 40h    BYTE    flag: 01h if server should process rom NetBIOS Post return
 41h    BYTE    flag: 01h if FCBs should be recycled
 42h  3 BYTEs    signature "DBG"
 45h    BYTE    last interrupt (21h or 6Fh)
 46h    BYTE    last INT 21 AH value
 47h    BYTE    last INT 6F AH value
 48h    WORD    last item posted
 4Ah    WORD    last item free-posted
 4Ch    WORD    last item handled by server
 4Eh    WORD    last redirector send NCB
 50h    WORD    last redirector receive NCB
 52h  4 BYTEs    signature "TABL"
 56h    WORD    offset of datagram buffer table header (see #1032)
 58h    WORD    offset of chat buffer table header (see #1032)
 5Ah    WORD    offset of Raw buffer table header (see #1032)
 5Ch    WORD    offset of Workstation buffer table header (see #1032)
 5Eh    WORD    offset of server receive-any table header (see #1032)
 60h    WORD    offset of Tiny buffer table header (see #1032)
 62h    WORD    offset of zero-length buffer table (NCBs) (see #1032)
 64h    WORD    offset of Rdr (Redirector Mount) table header (see #1032)
 66h    WORD    offset of Ntab (Redirector Session) table header (see #1032)
 68h    WORD    offset of FCB table header (see #1032)
 6Ah    WORD    offset of user file handle table header (see #1032)
 6Ch    WORD    offset of workstation printer RDR extension table header
 6Eh    WORD    offset of server shared device table header (see #1032)
 70h    WORD    offset of server connection table header (see #1032)
 72h    WORD    offset of server login table header (see #1032)
 74h    WORD    offset of server file table header (see #1032)
 76h    WORD    offset of server shared file table header (see #1032)
 78h    WORD    offset of server record lock table header (see #1032)
 7Ah    WORD    offset of remote printer claim table header (see #1032)
 7Ch    WORD    offset of remote printer device table header (see #1032)
 7Eh    WORD    offset of print server mount table header (see #1032)
 80h    WORD    offset of print server sessions table header (see #1032)
 82h    WORD    offset of print server print job structure table header
 84h    WORD    offset of print server pooled device table header (see #1032)
 86h    WORD    size of workstation buffer
 88h    WORD    size of server receive-any buffer
 8Ah    WORD    size of server raw I/O buffer
 8Ch  6 BYTEs    reserved
 92h    DWORD    pointer to profile pathname
 96h    BYTE    datagram retry count
 97h    BYTE    NetBIOS LAN adapter number
 98h  6 BYTEs    physical Ethernet address
 9Eh    BYTE    NetBIOS server name number
 9Fh    BYTE    NetBIOS redirector name number
 A0h    BYTE    10Net interrupt number
 A1h    BYTE    flag: chat is loaded
 A2h    BYTE    flag: INT 6F APIs permanently loaded
 A3h    BYTE    flag: file security present
 A4h    WORD    reserved
 A6h    BYTE    fixed mount bitmask for drives A:-H:
 A7h    BYTE    reserved
 A8h    WORD    10Net system flags (see #1036)
 AAh    BYTE    monitor flags (see #1037)
 ABh  5 BYTEs    reserved
 B0h    WORD    offset of monitor timer block
 B2h    WORD    offset of server timer block
 B4h    WORD    offset of chat timer block
 B6h    WORD    timer chain
 B8h  4 BYTEs    signature "TALS"
 BCh    WORD    number of 10Net sends
 BEh    WORD    number of 10Net receives
 C0h    WORD    number of no-buffer conditions
 C2h    WORD    number of dropped posted messages
 C4h    WORD    number of server NCB errors
 C6h    WORD    number of redirector NCB errors
 C8h    WORD    number of datagram send/receive errors
 CAh    WORD    number of dropped Whos
 CCh    WORD    number of dropped submits
 CEh    WORD    number of session aborts
 D0h    BYTE    number of NetBIOS interface-busy errors
 D1h    BYTE    last NetBIOS bad post command
 D2h    BYTE    last NetBIOS bad redirector command
 D3h    BYTE    do send datagram send/receive error command
 D4h    DWORD    -> DOS system parameter table
 D8h    WORD    number of DOS physical drives
 DAh    WORD    offset of DOS PSP field in DOS data segment
 DCh    WORD    offset of in-DOS flag in DOS data segment
 DEh    WORD    DOS data segment
 E0h    WORD    offset of DOS SFT in DOS data segment
 E2h    WORD    offset of number-of-physical-units field in DOS data segment
 E4h    WORD    10Net code segment
 E6h    WORD    10Net data segment
 E8h    WORD    10Net common server segment
 EAh    WORD    10Net file server segment
 ECh    WORD    10Net print server segment
 EEh    WORD    10Net remote printer segment
Note:    documentation lists field at offset D0h as a WORD, but all following
      offsets are as though it were a BYTE; if it is indeed a WORD, all
      offsets after D0h must be increased by one byte

Format of 10Net Table Header:
Offset    Size    Description    (Table 1032)
 -16  4 BYTEs    table identifier
 -12    WORD    peak number of tables allocated
 -10    WORD    number of tables currently in use
 -8    WORD    total number of tables
 -6    WORD    size of each table
 -4    WORD    offset of first allocated table
 -2    WORD    offset of first free table

Bitfields for 10NET services mask:
Bit(s)    Description    (Table 1033)
 0    workstation
 1    file server
 2    print queue server
 3    de-spool server

Bitfields for 10NET chat mask:
Bit(s)    Description    (Table 1034)
 0    chat permitted
 1    bell enabled
 2    chat keyboard initiated
 3    in INT 16 handler
 4    in Get Input
 5    display has timed out
 6    chat is idle

Bitfields for 10NET internal system bits:
Bit(s)    Description    (Table 1035)
 0    submit permitted
 1    submit initiated
 2    submit executing
 3    internal client call/chat/spool/autospool
 4    in spool termination
 5    print permitted
 6    waiting for keyboard input

Bitfields for 10NET System Flags:
Bit(s)    Description    (Table 1036)
 0    in NetBIOS
 1    processing INT 28
 2    is server
 3    in net user-DOS function
 4    in DOS user-DOS function
 5    in net for user non-DOS function
 6    in server DOS function
 7    in server non-DOS function
 8    in terminate
 10    in user on server request
 13    in DOS for user on server
 14    disable critical error handler

Bitfields for Monitor Flags:
Bit(s)    Description    (Table 1037)
 0    waiting for monitor response
 4    in monitor get-input routine
 5    monitor display timeout
 6    sensing for escape key
--------D-215E02-----------------------------
INT 21 - DOS 3.1+ network - SET NETWORK PRINTER SETUP STRING
    AX = 5E02h
    BX = redirection list index (see AX=5F02h)
    CX = length of setup string
    DS:SI -> setup string
Return: CF clear if successful
    CF set on error
        AX = error code (01h) (see #1020 at AH=59h/BX=0000h)
Note:    also supported by 10NET v5.0
SeeAlso: AX=5E03h,INT 2F/AX=111Fh
--------D-215E03-----------------------------
INT 21 - DOS 3.1+ network - GET NETWORK PRINTER SETUP STRING
    AX = 5E03h
    BX = redirection list index (see AX=5F02h)
    ES:DI -> 64-byte buffer for setup string
Return: CF clear if successful
        CX = length of setup string
        ES:DI buffer filled
    CF set on error
        AX = error code (01h) (see #1020 at AH=59h/BX=0000h)
Note:    also supported by 10NET v5.0, but 10NET is documented as using DS:SI
      instead of ES:DI
SeeAlso: AX=5E02h,INT 2F/AX=111Fh
--------D-215E04-----------------------------
INT 21 - DOS 3.1+ network - SET PRINTER MODE
    AX = 5E04h
    BX = redirection list index (see AX=5F02h)
    DX = mode
        bit 0: set if binary, clear if text (tabs expanded to blanks)
Return: CF set on error
        AX = error code (see #1020 at AH=59h/BX=0000h)
    CF clear if successful
Note:    calls INT 2F/AX=111Fh with 5E04h on stack
SeeAlso: AX=5E05h"DOS",INT 2F/AX=111Fh
--------N-215E04-----------------------------
INT 21 - 10NET v5.0 - INITIATE PRINT JOB
    AX = 5E04h
    BX = zero-based redirection list index (see AX=5F02h)
    DS:DX -> extended workstation printer setup structure (see #1038)
Return: CF clear if successful
    CF set on error
        AX = error code (see #1020 at AH=59h/BX=0000h)
SeeAlso: AX=5E05h"10NET",AX=5E06h"10NET"

Format of 10NET extended workstation printer setup structure:
Offset    Size    Description    (Table 1038)
 00h    BYTE    notification flags (see #1039)
 01h    BYTE    job control mask (see #1040)
 02h    WORD    days to retain file
 04h    WORD    test print length
 06h    BYTE    number of copies to print
 07h    BYTE    compression algorithm
 08h    BYTE    tab width (00h = don't expand)
 09h    BYTE    initiation type (00h normal, 01h non-spooled)
 0Ah 38 BYTEs    job start operation notification instructions
 30h 32 BYTEs    comment for job
 50h 64 BYTEs    output filename or non-spooled file

Bitfields for 10NET notification flags:
Bit(s)    Description    (Table 1039)
 0    user at print start
 1    operator at start, with reply
 2    user at print completion
 3    operator at completion, with reply
 4    user on queue switch
 5    operator on queue switch, with reply
 6    user on print error

Bitfields for 10NET job control mask:
Bit(s)    Description    (Table 1040)
 0    print banner page
 1    eject page at end of job
 2    mark as "held" (queue but don't print)
 3    rush job (queue at top)
 4    overwrite file with zeros before deletion
 5    hyperspool if possible
--------D-215E05-----------------------------
INT 21 - DOS 3.1+ network - GET PRINTER MODE
    AX = 5E05h
    BX = redirection list index (see AX=5F02h)
Return: CF set on error
        AX = error code (see #1020 at AH=59h/BX=0000h)
    CF clear if successful
        DX = printer mode (see AX=5E04h)
Note:    calls INT 2F/AX=111Fh with 5E05h on stack
SeeAlso: AX=5E04h"DOS",INT 2F/AX=111Fh
--------N-215E05-----------------------------
INT 21 - 10NET v5.0 - TERMINATE PRINT JOB
    AX = 5E05h
    BX = zero-based redirection list index (see AX=5F02h)
Return: CF clear if successful
    CF set on error
        AX = error code (see #1020 at AH=59h/BX=0000h)
Note:    this call resets the spool termination mode to "truncate"
      (see AX=5D08h)
SeeAlso: AX=5E04h"10NET",AX=5E06h
--------N-215E06-----------------------------
INT 21 - 10NET v5.0 - GET/SET 10NET WORKSTATION PRINTER SETUP STRUCTURE
    AX = 5E06h
    BX = zero-based redirection list index (see AX=5F02h)
    CX = operation (06h set, 07h get)
    DS:DX -> buffer for setup structure (same as first nine bytes of
          workstation printer setup) (see #1038)
Return: CF clear if successful
        DS:DX buffer updated on get
    CF set on error
        AX = error code (see #1020 at AH=59h/BX=0000h)
SeeAlso: AX=5E04h"10NET",AX=5E05h"10NET"
--------D-215F00-----------------------------
INT 21 - DOS 3.1+ network - GET REDIRECTION MODE
    AX = 5F00h
    BL = redirection type
        03h printer
        04h disk drive
Return: CF set on error
        AX = error code (see #1020 at AH=59h/BX=0000h)
    CF clear if successful
        BH = redirection state
        00h off
        01h on
Note:    calls INT 2F/AX=111Eh with AX on top of the stack
SeeAlso: AX=5F01h,INT 2F/AX=111Eh
--------D-215F01-----------------------------
INT 21 - DOS 3.1+ network - SET REDIRECTION MODE
    AX = 5F01h
    BL = redirection type
        03h printer
        04h disk drive
    BH = redirection state
        00h off
        01h on
Return: CF set on error
        AX = error code (see #1020 at AH=59h/BX=0000h)
    CF clear if successful
Notes:    when redirection is off, the local device (if any) rather than the
      remote device is used
    calls INT 2F/AX=111Eh with AX on top of the stack
SeeAlso: AX=5F00h,INT 2F/AX=111Eh,INT 60/AX=0002h
--------D-215F02-----------------------------
INT 21 - DOS 3.1+ network - GET REDIRECTION LIST ENTRY
    AX = 5F02h
    BX = zero-based redirection list index
    CX = driver signature
        0000h LANtastic
        4E57h ('NW') NetWare
    DS:SI -> 16-byte buffer for ASCIZ local device name or drive letter
          followed by colon
    ES:DI -> 128-byte buffer for ASCIZ network name
Return: CF clear if successful
        BH = device status
        00h valid
        01h invalid
        02h valid (connected from inside Windows for Workgroups v3.11)
        BL = device type
        03h printer
        04h disk drive
        CX = user data previously set with AX=5F03h
        DS:SI and ES:DI buffers filled
        DX,BP destroyed
    CF set on error
        AX = error code (01h,12h) (see #1020 at AH=59h/BX=0000h)
Notes:    this function is passed through to INT 2F/AX=111Eh by the DOS kernel
    error code 12h is returned if BX is greater than the size of the list
    also supported by Banyan VINES, PC-NFS, LANtastic, and 10NET
    supported by LapLink RemoteAccess but returns the local drive letter;
      the remote drive letter can be obtained with INT 2F/AX=Cxxxh
      (see INT 2F/AX=C000h"LapLink")
    the returned device name may or may not include a colon, depending on
      the network software
SeeAlso: AX=5F03h,AX=5F46h,INT 2F/AX=111Eh,INT 2F/AX=C000h"LapLink"
--------D-215F03-----------------------------
INT 21 - DOS 3.1+ network - REDIRECT DEVICE
    AX = 5F03h
    BL = device type
        03h printer
        04h disk drive
    CX = user data to save
        0000h for LANtastic
        4E57h ("NW") for NetWare 4.0 requester
    DS:SI -> ASCIZ local device name (16 bytes max)
    ES:DI -> ASCIZ network name + ASCIZ password (128 bytes max total)
Return: CF clear if successful
    CF set on error
        AX = error code (01h,03h,05h,08h,0Fh,12h) (see #1020 at AH=59h)
Notes:    if device type is disk drive, DS:SI must point at either a null string
      or a string consisting the drive letter followed by a colon; if a
      null string, the network attempts to access the destination without
      redirecting a local drive
    the DOS kernel calls INT 2F/AX=111Eh with AX on top of the stack
    also supported by Banyan VINES, LANtastic, and 10NET
SeeAlso: AX=5F02h,AX=5F04h,INT 2F/AX=111Eh,INT 60/AX=0002h
--------D-215F04-----------------------------
INT 21 - DOS 3.1+ network - CANCEL REDIRECTION
    AX = 5F04h
    DS:SI -> ASCIZ local device name or path
    CX = 4E57h ("NW") for NetWare 4.0 requester
Return: CF clear if successful
    CF set on error
        AX = error code (01h,03h,05h,08h,0Fh,12h) (see #1020 at AH=59h)
Notes:    the DS:SI string must be either a local device name, a drive letter
      followed by a colon, or a network directory beginning with two
      backslashes
    the DOS kernel calls INT 2F/AX=111Eh with AX on top of the stack
    also supported by Banyan VINES, LANtastic, and 10NET
    for NetWare, if only a server name is specified (i.e. "\\SERVER"),
      the connection to that server will be closed
SeeAlso: AX=5F03h,INT 2F/AX=111Eh,INT 60/AX=0003h
--------D-215F05-----------------------------
INT 21 - DOS 4.0+ network - GET EXTENDED REDIRECTION LIST ENTRY
    AX = 5F05h
    BX = redirection list index
    DS:SI -> buffer for ASCIZ source device name
    ES:DI -> buffer for destination ASCIZ network path
Return: CF set on error
        AX = error code (see #1020 at AH=59h/BX=0000h)
    CF clear if successful
        AX = server's network process ID handle (10NET)
        BH = device status flag (bit 0 clear if valid)
        BL = device type (03h if printer, 04h if drive)
        CX = stored parameter value (user data) from AX=5F03h
        BP = NETBIOS local session number
        DS:SI buffer filled
        ES:DI buffer filled
Notes:    the local session number allows sharing the redirector's session number
    if an error is caused on the NETBIOS LSN, the redirector may be unable
      to correctly recover from errors
    the DOS kernel calls INT 2F/AX=111Eh with AX on top of the stack
    supported by DR DOS 5.0
    also supported by 10NET v5.0
SeeAlso: AX=5F06h"Network",INT 2F/AX=111Eh
--------O-215F05-----------------------------
INT 21 - STARLITE architecture - MAP LOCAL DRIVE LETTER TO REMOTE FILE SYSTEM
    AX = 5F05h
    DL = drive number (0=A:)
    DS:SI -> ASCIZ name of the object to map the drive to
Return: CF set on error
        AX = error code (see #1020 at AH=59h/BX=0000h)
    CF clear if successful
SeeAlso: AX=5F06h"STARLITE",INT 60/AX=0002h
--------N-215F06-----------------------------
INT 21 U - Network - GET FULL REDIRECTION LIST
    AX = 5F06h
    ???
Return: ???
Notes:    similar to AX=5F02h and AX=5F05h, but also returns redirections
      excluded from those calls for various reasons
    calls INT 2F/AX=111Eh with AX on top of the stack
SeeAlso: AX=5F05h"DOS",INT 2F/AX=111Eh
--------O-215F06-----------------------------
INT 21 - STARLITE architecture - UNMAP DRIVE LETTER
    AX = 5F06h
    DL = drive to be unmapped (0=A:)
Return: CF set on error
        AX = error code (see #1020 at AH=59h/BX=0000h)
    CF clear if successful
SeeAlso: AX=5F05h"STARLITE",INT 60/AX=0003h
--------D-215F07-----------------------------
INT 21 - DOS 5+ - ENABLE DRIVE
    AX = 5F07h
    DL = drive number (0=A:)
Return: CF clear if successful
    CF set on error
        AX = error code (0Fh) (see #1020 at AH=59h/BX=0000h)
Notes:    simply sets the "valid" bit in the drive's CDS
    this function is not supported by Novell DOS 7 through at least
      Update 4, but support was added by Update 13
SeeAlso: AH=52h,AX=5F08h"DOS"
--------O-215F07-----------------------------
INT 21 - STARLITE architecture - MAKE NAMED OBJECT AVAILABLE ON NETWORK
    AX = 5F07h
    DS:SI -> ASCIZ name of object to offer to network
    ES:DI -> ASCIZ name under which object will be known on the network
        MUST begin with three slashes
Return: CF set on error
        AX = error code (see #1020 at AH=59h/BX=0000h)
    CF clear if successful
SeeAlso: AX=5F08h"STARLITE"
--------D-215F08-----------------------------
INT 21 - DOS 5+ - DISABLE DRIVE
    AX = 5F08h
    DL = drive number (0=A:)
Return: CF clear if successful
    CF set on error
        AX = error code (0Fh) (see #1020 at AH=59h/BX=0000h)
Notes:    simply clears the "valid" bit in the drive's CDS
    this function is not supported by Novell DOS 7 through at least
      Update 4, but support was added by Update 13
SeeAlso: AH=52h,AX=5F07h"DOS"
--------O-215F08-----------------------------
INT 21 - STARLITE architecture - REMOVE GLOBAL NETWORK NAME OF OBJECT
    AX = 5F08h
    DS:SI -> ASCIZ network name (not local name) of object to unshare
Return: CF set on error
        AX = error code (see #1020 at AH=59h/BX=0000h)
    CF clear if successful
SeeAlso: AX=5F07h"STARLITE"
--------O-215F09-----------------------------
INT 21 - STARLITE architecture - BIND TO NETWORK DEVICE
    AX = 5F09h
    DS:DX -> ASCIZ name of the device driver to attach to
Return: CF set on error
        AX = error code (see #1020 at AH=59h/BX=0000h)
    CF clear if successful
Note:    the STARLITE distributed file system can attach to multiple networks
      simultaneously
SeeAlso: AX=5F0Ah
--------O-215F0A-----------------------------
INT 21 - STARLITE architecture - DETACH FROM NETWORK DEVICE
    AX = 5F0Ah
    DS:DX -> ASCIZ name of device driver to detach from
Return: CF set on error
        AX = error code (see #1020 at AH=59h/BX=0000h)
    CF clear if successful
SeeAlso: AX=5F09h
--------N-215F30-----------------------------
INT 21 U - LAN Manager Enhanced DOS - GET REDIRECTOR VERSION
    AX = 5F30h
Return: AX = version (AH=major,AL=minor)
--------N-215F32-----------------------------
INT 21 u - Named Pipes - LOCAL DosQNmPipeInfo
    AX = 5F32h
    BX = handle
    CX = size of _PIPEINFO structure
    DX = level (must be 0001h)
    DS:SI -> _PIPEINFO structure (see #1041)
Return: CF clear if successful
        _PIPEINFO structure filled in
    CF set on error
        AX = error code
Note:    this function was introduced by LAN Manager but is also supported by
      the Novell DOS Named Pipe Extender, Banyan VINES, OS/2 Virtual DOS
      Machines, and others
SeeAlso: AX=5F33h,AX=5F34h

Format of Named Pipes _PIPEINFO structure:
Offset    Size    Description    (Table 1041)
 00h    WORD    size of outgoing buffer
 02h    WORD    size of incoming buffer
 04h    BYTE    maximum number of instances allowed
 05h    BYTE    current number of instances
 06h    BYTE    length of the name (including terminating NUL)
 07h  N BYTEs    name
--------N-215F33-----------------------------
INT 21 u - Named Pipes - LOCAL DosQNmPHandState
    AX = 5F33h
    BX = handle
Return: CF clear if successful
        AH = pipe mode bit mask (see #1042)
        AL = maximum number of instances
    CF set on error
        AX = error code
Note:    this function was introduced by LAN Manager but is also supported by
      the Novell DOS Named Pipe Extender, Banyan VINES, OS/2 Virtual DOS
      Machines, and others
SeeAlso: AX=5F32h,AX=5F34h

Bitfields for Named Pipes pipe mode:
Bit(s)    Description    (Table 1042)
 7    set if nonblocking, clear if blocking
 6    set if server end, clear if client end
 2    set if write in message mode, clear if write in byte mode
 0    set if read in message mode, clear if read in byte mode
--------N-215F34-----------------------------
INT 21 u - Named Pipes - LOCAL DosSetNmPHandState
    AX = 5F34h
    BX = handle
    CX = pipe mode bit mask
        bit 15: set if nonblocking, clear if blocking
        bit     8: set if read in message mode, clear if read in byte mode
Return: CF clear if successful
    CF set if error
        AX = error code
Note:    this function was introduced by LAN Manager but is also supported by
      the Novell DOS Named Pipe Extender, Banyan VINES, OS/2 Virtual DOS
      Machines, and others
SeeAlso: AX=5F32h,AX=5F33h,AX=5F36h
--------N-215F35-----------------------------
INT 21 u - Named Pipes - LOCAL DosPeekNmPipe
    AX = 5F35h
    BX = handle
    CX = buffer length
    DS:SI -> buffer
Return: CF set on error
        AX = error code
    CF clear if successful (LAN Manager v1-v2)
    AX = 0000h if successful (LAN Manager 3.x)
    ---if successful---
        CX = bytes read
        SI = bytes left in the pipe
        DX = bytes left in the current message
        AX = pipe status (v1-v2) (see #1043)
        DI = pipe status (v3.x)
Note:    this function was introduced by LAN Manager but is also supported by
      the Novell DOS Named Pipe Extender, Banyan VINES, OS/2 Virtual DOS
      Machines, and others
SeeAlso: AX=5F38h,AX=5F39h,AX=5F51h

(Table 1043)
Values for pipe status:
 0001h    disconnected
 0002h    listening
 0003h    connected
 0004h    closing
--------N-215F36-----------------------------
INT 21 u - Named Pipes - LOCAL DosTransactNmPipe
    AX = 5F36h
    BX = handle
    CX = in buffer length
    DS:SI -> in buffer
    DX = out buffer length
    ES:DI -> out buffer
Return: CF clear if successful
        CX = bytes read
    CF set on error
        AX = error code
Note:    this function was introduced by LAN Manager but is also supported by
      the Novell DOS Named Pipe Extender, Banyan VINES, OS/2 Virtual DOS
      Machines, and others
SeeAlso: AX=5F34h,AX=5F37h
--------N-215F37-----------------------------
INT 21 u - Named Pipes - DosCallNmPipe
    AX = 5F37h
    DS:SI -> DosCallNmPipe stack frame (see #1044)
Return: CF clear if successful
        CX = bytes read
    CF set on error
        AX = error code
Note:    this function was introduced by LAN Manager but is also supported by
      the Novell DOS Named Pipe Extender, Banyan VINES, OS/2 Virtual DOS
      Machines, and others
SeeAlso: AX=5F36h,AX=5F38h

Format of Named Pipes DosCallNmPipe stack frame:
Offset    Size    Description    (Table 1044)
 00h    DWORD    timeout
 04h    DWORD    -> bytes read WORD (not used!)
 08h    WORD    out buffer length
 0Ah    DWORD    address of out buffer
 0Eh    WORD    in buffer length
 10h    DWORD    address of in buffer
 14h    DWORD    address of pipe name
--------N-215F38-----------------------------
INT 21 u - Named Pipes - LOCAL DosWaitNmPipe - AWAIT AVAIL. OF PIPE INSTANCE
    AX = 5F38h
    DS:DX -> pipe name
    BX:CX = timeout value
Return: CF clear if successful
    CF set if error
        AX = error code
Notes:    when a client gets a return code of ERROR_PIPE_BUSY on attempting to
      open a pipe, it should issue this call to wait until the pipe
      instance becomes available again; on return from this call, the
      client must attempt to open the pipe once again
    this function was introduced by LAN Manager but is also supported by
      the Novell DOS Named Pipe Extender, Banyan VINES, OS/2 Virtual DOS
      Machines, and others
SeeAlso: AX=5F37h,AX=5F39h
--------N-215F39-----------------------------
INT 21 U - Named Pipes - LOCAL DosRawReadNmPipe
    AX = 5F39h
    BX = handle
    CX = buffer length
    DS:DX -> buffer
Return: CF clear if successful
        CX = bytes read
    CF set if error
        AX = error code
Notes:    this function was introduced by LAN Manager but is also supported by
      the Novell DOS Named Pipe Extender, Banyan VINES, OS/2 Virtual DOS
      Machines, and others
    not documented in the LAN Manager Toolkit
SeeAlso: AX=5F35h,AX=5F3Ah,INT 2F/AX=1186h
--------N-215F3A-----------------------------
INT 21 U - Named Pipes - LOCAL DosRawWriteNmPipe
    AX = 5F3Ah
    BX = handle
    CX = buffer length
    DS:DX -> buffer
Return: CF clear if successful
        CX = bytes written
    CF set if error
        AX = error code
Notes:    this function was introduced by LAN Manager but is also supported by
      the Novell DOS Named Pipe Extender, Banyan VINES, OS/2 Virtual DOS
      Machines, and others
    not documented in the LAN Manager Toolkit
SeeAlso: AX=5F39h,AX=5F3Bh,INT 2F/AX=118Fh
--------N-215F3B-----------------------------
INT 21 u - LAN Manager Enhanced DOS - NetHandleSetInfo
    AX = 5F3Bh
    BX = handle
    CX = handle_info_1 structure length or sizeof DWORD
    DI = parameter number to set
        0000h all
        0001h number of milliseconds
        0002h number of characters
    DS:DX -> handle_info_1 structure (DI=0000h) (see #1045)
        or DWORD (DI=0001h or 0002h)
    SI = level of information (0001h)
Return: CF clear if successful
        CX = total bytes available
    CF set if error
        AX = error code
SeeAlso: AX=5F3Ch

Format of LAN Manager handle_info_1 structure:
Offset    Size    Description    (Table 1045)
 00h    DWORD    number of milliseconds which workstation collects data before
          it sends the data to the named pipe
 04h    DWORD    number of characters which workstation collects before it
          sends the data to the named pipe
--------N-215F3C-----------------------------
INT 21 u - LAN Manager Enhanced DOS - NetHandleGetInfo
    AX = 5F3Ch
    BX = handle
    CX = length of handle_info_1 structure
    DS:DX -> handle_info_1 structure (see #1045)
    SI = level of information (must be 0001h)
Return: CF clear if successful
        CX = total bytes available
    CF set if error
        AX = error code
SeeAlso: AX=5F3Bh
--------N-215F3D-----------------------------
INT 21 U - LAN Manager Enhanced DOS - WRITE MAILSLOT???
    AX = 5F3Dh
    ???
Return: ???
--------N-215F3E-----------------------------
INT 21 u - LAN Manager Enhanced DOS - LOCAL NetSpecialSMB
    AX = 5F3Eh
    ???
Return: ???
Note:    This function is not documented anywhere in the LAN Manager 2.x Toolkit
      but was documented in LAN Manager 1.x manuals.
--------N-215F3F-----------------------------
INT 21 U - LAN Manager Enhanced DOS - REMOTE API CALL
    AX = 5F3Fh
    CX = api number
    ES:DI -> data descriptor
    ES:SI -> parameter descriptor
    ES:DX -> auxiliary descriptor (if DX <> 0)
    ???
Return: ???
--------N-215F40-----------------------------
INT 21 u - LAN Manager Enhanced DOS - LOCAL NetMessageBufferSend
    AX = 5F40h
    DS:DX -> NetMessageBufferSend parameter structure (see #1046)
Return: AX = error code

Format of LAN Manager NetMessageBufferSend parameter structure:
Offset    Size    Description    (Table 1046)
 00h    DWORD    -> recipient name (name for specific user, name* for domain
              wide name, * for broadcast)
 04h    DWORD    -> buffer
 08h    WORD    length of buffer
--------N-215F41-----------------------------
INT 21 u - LAN Manager Enhanced DOS - LOCAL NetServiceEnum
    AX = 5F41h
    BL = level of detail (0000h, 0001h or 0002h)
    CX = buffer length
    ES:DI -> buffer of service_info_0, service_info_1, or service_info_2
        (see #1047,#1048,#1049)
Return: CF clear if successful
        CX = entries read
        DX = total available
    CF set on error
        AX = error code

Format of LAN Manager service_info_0 structure:
Offset    Size    Description    (Table 1047)
 00h 16 BYTEs    name
SeeAlso: #1048,#1049

Format of service_info_1 structure:
Offset    Size    Description    (Table 1048)
 00h 16 BYTEs    name
 10h    WORD    status bitmask (see #1050)
 12h    DWORD    status code (see #1051)
        (also see Microsoft LAN Manager Programmer's Reference)
 16h    WORD    process id
SeeAlso: #1047,#1049

Format of service_info_2 structure:
Offset    Size    Description    (Table 1049)
 00h 16 BYTEs    name
 10h    WORD    status bitmask (see #1050)
 12h    DWORD    status code (see #1051)
 16h    WORD    process id
 18h 64 BYTEs    text
SeeAlso: #1047,#1048

Bitfields for LAN Manager status bitmask:
Bit(s)    Description    (Table 1050)
 0,1    00 uninstall
        01 install pending
        10 uninstall pending
        11 installed
 2,3    00 active
        01 Continue pending
        10 Pause pending
        11 paused
 4    uninstallable
 5    pausable
 8    disk redirector paused
 9    spooled device redirector paused (printing)
 10    communication device redirector paused

(Table 1051)
Values for LAN Manager status code:
 high word
    3051 Bad parameter value
    3052 A parameter is missing
    3053 An unknown parameter was specified
    3054 The resource is insufficient
    3055 Configuration is faulty
    3056 An MS-DOS or MS OS/2 error occured
    3057 An internal error occured
    3058 An ambiguous parameter name was given
    3059 A duplicate parameter exists
    3060 The service was terminated by NetSeviceControl when it did not respond
    3061 The service program file could not be executed
    3062 The subservice failed to start
    3063 There is a conflict in the value or use of these parameters
    3064 There is a problem with the file
 low word
    3070 There is insufficient memory
    3071 There is insufficeient disk space
    3072 Unable to create thread
    3073 Unable to create process
    3074 A security failure occured
    3075 There is bad or missing default path
    3076 Network software is not installed
    3077 Server software is not installed
    3078 The server could not access the UAS database
    3079 The action requires user-level security
    3080 The log directory is invalid
    3081 The LAN group specificed could not be used
    3082 The computername is being used as a message alias on another computer
    3083 The workstation failed to announce the servername
    3084 The user accounts system is not configured properly
--------N-215F42-----------------------------
INT 21 u - LAN Manager Enhanced DOS - LOCAL NetServiceControl
    AX = 5F42h
    DH = opcode
        00h interrogate status
        01h pause
        02h continue
        03h uninstall
    DL = argument
        01h disk resource
        02h print resource
        04h communications resource (not implemented for DOS)
    ES:BX -> NetServiceControl parameter structure (see #1052)
Return: CF clear if successful
    CF set on error
        AX = error code

Format of LAN Manager NetServiceControl parameter structure:
Offset    Size    Description    (Table 1052)
 00h    DWORD    -> service name
 04h    WORD    result buffer size
 06h    DWORD    -> result buffer as service_info_2 structure
--------N-215F43-----------------------------
INT 21 u - LAN Manager Enhanced DOS - LOCAL DosPrintJobGetId
    AX = 5F43h
    BX = handle of remote print job
    CX = size of PRIDINFO struture
    ES:DI -> PRIDINFO structure (see #1053)
Return: CF clear if successful
        PRIDINFO filled in
    CF set on error
        AX = error code

Format of LAN Manager PRIDINFO structure:
Offset    Size    Description    (Table 1053)
 00h    WORD    job id
 02h 16 BYTEs    server name
 12h 13 BYTEs    queue name
 1Fh  1 BYTE    pad
--------N-215F44-----------------------------
INT 21 - LAN Manager Enhanced DOS - LOCAL NetWkstaGetInfo
    AX = 5F44h
    BX = information level (00h, 01h, or 0Ah)
    CX = buffer size
    DX = 0000h
    ES:DI -> buffer in which to store info (see #1054,#1055,#1056),
          including any returned strings
Return: AX = error code
    DX = amount of buffer required, unchanged if supplied buffer large
          enough to hold data
SeeAlso: AX=5F45h,AX=5F49h

Format of LAN Manager wksta_info_0 structure:
Offset    Size    Description    (Table 1054)
 00h    WORD     reserved (0)
 02h    DWORD     reserved (0)
 06h    DWORD     -> path to computer's LANMAN directory
 0Ah    DWORD     -> computername of the workstation
 0Eh    DWORD     -> username of user logged onto workstation
 12h    DWORD     -> domain to which workstation belongs
 16h    WORD     LAN Manager version number (2 bytes, Major, Minor)
 18h    DWORD     reserved (0)
 1Ch    WORD     number of seconds workstation waits for resource availability
 1Eh    DWORD     delay (in millsecs) before sending data to resource
 22h    WORD     reserved (0)
 24h    WORD     reserved (0)
 26h    WORD     ???
 28h    WORD     number of seconds to maintain an inactive connection
 2Ah    WORD     number of seconds an inactive search continues
 2Ch    WORD     threads to dedicate to network (not supported in MSDOS)
 2Eh    WORD     number of simultaneous commands sent to network
 30h    WORD     reserved6 (must be 0)
 32h    WORD     number of internal buffers
 34h    WORD     size (in bytes) of each internal buffer
 36h    WORD     max size (in bytes) of an internal cache buffer (not MSDOS)
 38h    WORD     seconds before disconnecting inactive session (not MSDOS)
 3Ah    WORD     size (in bytes) of an internal error buffer (not MSDOS)
 3Ch    WORD     number of clients that can receive alert messages (not MSDOS)
 3Eh    WORD     number of services that can be started on workstation
 40h    WORD     max size (in kilobytes) of error log (not MSDOS)
 42h    WORD     number of secs before closing inactive print jobs (not MSDOS)
 44h    WORD     number of character buffers for workstation
 46h    WORD     max size (in bytes) of character buffer
 48h    DWORD     -> name of server that validated logon
 4Ch    DWORD     -> workstation heuristics
 50h    WORD     number of mailslots allowed
Note:    pointers to strings are set to 0000h:0000h if there is insufficient
      space in the buffer to hold them
SeeAlso: #1055,#1056

Format of LAN Manager wksta_info_1 structure:
Offset    Size    Description    (Table 1055)
 00h 82 BYTEs    wksta_info_0 structure (see #1054)
 52h    DWORD     -> name of domain which user is logged on to
 56h    DWORD     -> all domains in which computer is enlisted
 5Ah    WORD     number of buffers to allocate for receiving datagrams
SeeAlso: #1056

Format of LAN Manager wksta_info_10 structure:
Offset    Size    Description    (Table 1056)
 00h    DWORD     -> computername of the workstation
 04h    DWORD     -> username of user logged onto workstation
 08h    DWORD     -> domain to which workstation belongs
 0Ch    WORD     LAN Manager version number (2 bytes, Major, Minor)
 0Eh    DWORD     -> name of domain which user is loggod on to
 12h    DWORD     -> all domains in which computer is enlisted
Note:    pointers to strings are set to 0000h:0000h if there is insufficient
      space in the buffer to hold them
SeeAlso: #1054,#1055
--------N-215F45-----------------------------
INT 21 u - LAN Manager Enhanced DOS - LOCAL NetWkstaSetInfo
    AX = 5F45h
    BX = level (0000h or 0001h)
    CX = buffer size
    DX = parameter to set
    ES:DI -> buffer
Return: CF clear if successful
    CF set if error
        AX = error code
SeeAlso: AX=5F44h
--------N-215F46-----------------------------
INT 21 u - LAN Manager Enhanced DOS - LOCAL NetUseEnum
    AX = 5F46h
    BX = level (0000h or 0001h)
    CX = size of buffer
    ES:DI -> buffer of use_info_0 or use_info_1 structures
          (see #1057,#1058)
Return: CF clear if successful
        CX = entries read
        DX = total available entries
    CF set if error
        AX = error code
SeeAlso: AX=5F47h,AX=5F48h,AX=5F4Ch

Format of LAN Manager use_info_0 structure:
Offset    Size    Description    (Table 1057)
 00h  9 BYTEs    local device name
 09h    BYTE    padding
 0Ah    DWORD    -> remote device name in UNC form \\server\share
SeeAlso: #1058

Format of LAN Manager use_info_1 structure:
Offset    Size    Description    (Table 1058)
 00h  9 BYTEs    Local device name
 09h    BYTE    padding
 0Ah    DWORD    -> remote device name in UNC form \\server\share
 0Eh    DWORD    -> password
 12h    WORD    network link status
        (00h OK, 02h disconnected, else unsure)
 14h    WORD    use type (-1 wildcard, 0 disk, 1 print, 2 com, 3 ipc)
 16h    WORD    ignored
 18h    WORD    ignored
SeeAlso: #1057
--------N-215F47-----------------------------
INT 21 u - LAN Manager Enhanced DOS - LOCAL NetUseAdd
    AX = 5F47h
    BX = level (0001h)
    CX = size of use_info_1 structure
    ES:DI -> use_info_1 structure (see #1058)
Return: CF clear on success
    CF set on error
        AX = error code
SeeAlso: AX=5F46h,AX=5F48h
--------N-215F48-----------------------------
INT 21 u - LAN Manager Enhanced DOS - LOCAL NetUseDel
    AX = 5F48h
    BX = force level
        0000h no force
        0001h force
        0002h lots of force
    ES:DI -> buffer as either the local device name or UNC remote name
Return: CF clear on success
    CF set on error
        AX = error code
SeeAlso: AX=5F46h,AX=5F48h,AX=5F49h
--------N-215F49-----------------------------
INT 21 u - LAN Manager Enhanced DOS - NetUseGetInfo
    AX = 5F49h
    DS:DX -> NetUseGetInfo parameter structure (see #1059)
Return: CF clear on success
        DX = total available
    CF set on error
        AX = error code
SeeAlso: AX=5F44h,AX=5F47h

Format of LAN Manager NetUseGetInfo parameter structure:
Offset    Size    Description    (Table 1059)
 00h    DWORD    pointer to either the local device name or UNC remote name
 04h    WORD    level of information (0000h or 0001h)
 06h    DWORD    pointer to buffer of use_info_0 or use_info_1 structures
 0Ah    WORD    length of buffer
--------N-215F4A-----------------------------
INT 21 u - LAN Manager Enhanced DOS - LOCAL NetRemoteCopy
    AX = 5F4Ah
    DS:DX -> NetRemoteCopy parameter structure (see #1060)
Return: CF clear if successful
    CF set on error
        AX = error code
SeeAlso: AX=5F4Bh

Format of LAN Manager NetRemoteCopy parameter structure:
Offset    Size    Description    (Table 1060)
 00h    DWORD    -> source name as UNC
 04h    DWORD    -> destination name as UNC
 08h    DWORD    -> source password
 0Ch    DWORD    -> destination password
 10h    WORD    destination open bitmap
        if destination path exists
            0000h open fails
            0001h file is appended
            0002h file is overwritten
        if destination path doesn't exist
            0000h open fails
            0010h file is created
 12h    WORD    copy control bitmap (see #1061)
 14h    DWORD    -> copy_info buffer
 18h    WORD    length of copy_info buffer

Bitfields for LAN Manager copy control:
Bit(s)    Description    (Table 1061)
 0    destination must be a file
 1    destination must be a directory
 2    destination is opened in ascii mode instead of binary
 3    source is opened in ascii mode instead of binary
 4    verify all write operations
--------N-215F4B-----------------------------
INT 21 u - LAN Manager Enhanced DOS - LOCAL NetRemoteMove
    AX = 5F4Bh
    DS:DX -> NetRemoteMove parameter structure (see #1062)
Return: CF clear if successful
    CF set on error
        AX = error code
SeeAlso: AX=5F4Ah

Format of LAN Manager NetRemoteMove parameter structure:
Offset    Size    Description    (Table 1062)
 00h    DWORD    -> source name as UNC
 04h    DWORD    -> destination name as UNC
 08h    DWORD    -> source password
 0Ch    DWORD    -> destination password
 10h    WORD    destination open bitmap
        if destination path exists
            0000h open fails
            0001h file is appended
            0002h file is overwritten
        if destination path doesn't exist
            0000h open fails
            0010h file is created
 12h    WORD    move control bitmap
            0001h destination must be a file
            0002h destination must be a directory
 14h    DWORD    -> move_info buffer
 18h    WORD    length of move_info buffer
--------N-215F4C-----------------------------
INT 21 u - LAN Manager Enhanced DOS - LOCAL NetServerEnum
    AX = 5F4Ch
    BX = level (0000h or 0001h)
    CX = buffer length
    ES:DI -> buffer in which to store information
Return: CF clear if successful
        ES:DI -> server_info_X structures (depending on level)
          (see #1063,#1064)
        BX = entries read
        CX = total entries available
    CF set on error
        AX = error code
Notes:    this function is also supported by the Novell DOS Named Pipe Extender
    this function has been obseleted by NetServerEnum2
SeeAlso: AX=5F53h

Format of LAN Manager server_info_0 structure:
Offset    Size    Description    (Table 1063)
 00h 16 BYTEs    name
SeeAlso: #1064

Format of LAN Manager server_info_1 structure:
Offset    Size    Description    (Table 1064)
 00h 16 BYTEs    name
 10h    BYTE    major version in lower nibble
 11h    BYTE    minor version
 12h    DWORD    server type bitmask (see #1065)
 16h    DWORD    -> comment string
SeeAlso: #1063

Bitfields for LAN Manager server type:
Bit(s)    Description    (Table 1065)
 0    workstation
 1    server
 2    SQL server
 3    primary domain controller
 4    backup domain controller
 5    time server
 6    Apple File Protocol (AFP) server
 7    Novell server
 8    Domain Member (v2.1+)
 9    Print Queue server (v2.1+)
 10    Dialin server (v2.1+)
 11    Unix server (v2.1+)
--------N-215F4D-----------------------------
INT 21 u - LAN Manager Enhanced DOS - DosMakeMailslot
    AX = 5F4Dh
    BX = message size
    CX = mailslot size (must be bigger than message size by at least 1)
               (minimum 1000h, maximum FFF6h)
               (buffer must be 9 bytes bigger than this)
    DS:SI -> name
    ES:DI -> memory buffer
Return: CF clear if successful
        AX = handle
    CF set on error
        AX = error code
SeeAlso: AX=5F4Eh,AX=5F4Fh,AX=5F50h,AX=5F51h
--------N-215F4E-----------------------------
INT 21 u - LAN Manager Enhanced DOS - DosDeleteMailslot
    AX = 5F4Eh
    BX = handle
Return: CF clear if successful
        ES:DI -> memory to be freed (allocated during DosMakeMailslot)
    CF set on error
        AX = error code
SeeAlso: AX=5F4Dh,AX=5F4Fh
--------N-215F4F-----------------------------
INT 21 u - LAN Manager Enhanced DOS - DosMailslotInfo
    AX = 5F4Fh
    BX = handle
Return: CF clear if successful
        AX = max message size
        BX = mailslot size
        CX = next message size
        DX = next message priority
        SI = number of messages waiting
    CF set on error
        AX = error code
SeeAlso: AX=5F4Dh,AX=5F4Eh,AX=5F50h
--------N-215F50-----------------------------
INT 21 u - LAN Manager Enhanced DOS - DosReadMailslot
    AX = 5F50h
    BX = handle
    DX:CX = timeout
    ES:DI -> buffer
Return: CF clear if successful
        AX = bytes read
        CX = next item's size
        DX = next item's priority
    CF set on error
        AX = error code
SeeAlso: AX=5F4Dh,AX=5F4Fh,AX=5F51h,AX=5F52h
--------N-215F51-----------------------------
INT 21 u - LAN Manager Enhanced DOS - DosPeekMailslot
    AX = 5F51h
    BX = handle
    ES:DI -> buffer
Return: CF clear if successful
        AX = bytes read
        CX = next item's size
        DX = next item's priority
    CF set on error
        AX = error code
SeeAlso: AX=5F35h,AX=5F4Fh,AX=5F50h,AX=5F52h
--------N-215F52-----------------------------
INT 21 u - LAN Manager Enhanced DOS - DosWriteMailslot
    AX = 5F52h
    BX = class
    CX = length of buffer
    DX = priority
    ES:DI -> DosWriteMailslot parameter structure (see #1066)
    DS:SI -> mailslot name
Return: CF clear if successful
    CF set on error
        AX = error code
SeeAlso: AX=5F4Fh,AX=5F50h,AX=5F51h

Format of LAN Manager DosWriteMailslot parameter structure:
Offset    Size    Description    (Table 1066)
 00h    DWORD    timeout
 04h    DWORD    -> buffer
--------N-215F53-----------------------------
INT 21 u - LAN Manager Enhanced DOS - NetServerEnum2
    AX = 5F53h
    DS:SI -> NetServerEnum2 parameter structure (see #1067)
Return: CF clear if successful
        BX = entries read
        CX = total entries available
    CF set on error
        AX = error code
SeeAlso: AX=5F4Ch

Format of LAN Manager NetServerEnum2 parameter structure:
Offset    Size    Description    (Table 1067)
 00h    WORD    level (0000h or 0001h)
 02h    DWORD    -> buffer as array of server_info_??? structures (see #1069)
 06h    WORD    length of buffer
 08h    DWORD    server type bitmask (see #1068)
 0Ch    DWORD    -> Domain name (may be 0000h:0000h for all local domains)

Bitfields for LAN Manager server type:
Bit(s)    Description    (Table 1068)
 0    workstation
 1    server
 2    SQL server
 3    primary domain controller
 4    backup domain controller
 5    time server
 6    Apple File Protocol (AFP) server
 7    Novell server
 8    Domain Member (v2.1+)
 9    Print Queue server (v2.1+)
 10    Dialin server (v2.1+)
 11    Unix server (v2.1+)
Note:    set all (FFFFFFFFh) for All Types

Format of LAN Manager server_info_0 structure:
Offset    Size    Description    (Table 1069)
 00h 16 BYTEs    name
SeeAlso: #1070

Format of LAN Manager server_info_1 structure:
Offset    Size    Description    (Table 1070)
 00h 16 BYTEs    name
 10h    BYTE    major version in lower nibble
 11h    BYTE    minor version
 12h    DWORD    server type (bits 0-11) (see #1068)
 16h    DWORD    -> comment string
SeeAlso: #1069
--------N-215F55----------------------------
INT 21 U - LAN Manager Enhanced DOS - KILL ALL CONNECTIONS???
    AX = 5F55h
    BX = ???
Return: CF clear if successful
    CF set on error
        AX = error code
--------N-215F80-----------------------------
INT 21 - LANtastic - GET LOGIN ENTRY
    AX = 5F80h
    BX = login entry index (0-based)
    ES:DI -> 16-byte buffer for machine name
Return: CF clear if successful
        buffer filled with machine name ("\\" prefix removed)
        DL = adapter number (v3+)
    CF set on error
        AX = error code
Note:    the login entry index corresponds to the value BX used in AX=5F83h
SeeAlso: AX=5F83h
--------N-215F81-----------------------------
INT 21 - LANtastic - LOGIN TO SERVER
    AX = 5F81h
    ES:DI -> ASCIZ login path followed immediately by ASCIZ password
    BL = adapter number
        FFh try all valid adapters
        00h-07h try only specified adapter
Return: CF clear if successful
    CF set on error
        AX = error code
Notes:    login path is of form "\\machine\username"
    if no password is used, the string at ES:DI must be terminated with
      three NULs for compatibility with LANtastic v3.0.
SeeAlso: AX=5F82h,AX=5F84h
--------N-215F82-----------------------------
INT 21 - LANtastic - LOGOUT FROM SERVER
    AX = 5F82h
    ES:DI -> ASCIZ server name (in form "\\machine")
Return: CF clear if successful
    CF set on error
        AX = error code
SeeAlso: AX=5F81h,AX=5F88h,AX=5FCBh
--------N-215F83-----------------------------
INT 21 - LANtastic - GET USERNAME ENTRY
    AX = 5F83h
    BX = login entry index (0-based)
    ES:DI -> 16-byte buffer for username currently logged into
Return: CF clear if successful
        DL = adapter number (v3+)
    CF set on error
        AX = error code
Note:    the login entry index corresponds to the value BX used in AX=5F80h
SeeAlso: AX=5F80h
--------N-215F84-----------------------------
INT 21 - LANtastic - GET INACTIVE SERVER ENTRY
    AX = 5F84h
    BX = server index not currently logged into
    ES:DI -> 16-byte buffer for server name which is available for logging
        in to ("\\" prefix omitted)
Return: CF clear if successful
        DL = adapter number to non-logged in server is on
    CF set on error
        AX = error code
SeeAlso: AX=5F81h
--------N-215F85-----------------------------
INT 21 - LANtastic - CHANGE PASSWORD
    AX = 5F85h
    ES:DI -> buffer containing "\\machine\oldpassword" 00h "newpassword"00h
Return: CF clear if successful
    CF set on error
        AX = error code
Notes:    must be logged into the named machine
    this function is illegal for group accounts
--------N-215F86-----------------------------
INT 21 - LANtastic - DISABLE ACCOUNT
    AX = 5F86h
    ES:DI -> ASCIZ machine name and password in form "\\machine\password"
Return: CF clear if successful
    CF set on error
        AX = error code
Note:    must be logged into the named machine and concurrent logins set to 1
      by NET_MGR.  Requires system manager to re-enable account.
--------N-215F87-----------------------------
INT 21 - LANtastic v3+ - GET ACCOUNT
    AX = 5F87h
    DS:SI -> 128-byte buffer for account information (see #1071)
    ES:DI -> ASCIZ machine name in form "\\machine"
Return: CF clear if successful
    CF set on error
        AX = error code
    BX destroyed
Note:    must be logged into the specified machine

Format of LANtastic user account structure:
Offset    Size    Description    (Table 1071)
 00h 16 BYTEs    blank-padded username (zero-padded for v4.x)
 10h 16 BYTEs    reserved (00h)
 20h 32 BYTEs    user description
 40h    BYTE    privilege bits (see #1072)
 41h    BYTE    maximum concurrent users
 42h 42 BYTEs    bit map for disallowed half hours, beginning on Sunday
        (bit set if half-hour not an allowed time)
 6Ch    WORD    internal (0002h)
 6Eh  2 WORDs    last login time
 72h  2 WORDs    account expiration date (MS-DOS-format year/month:day)
 76h  2 WORDs    password expiration date (0 = none)
 7Ah    BYTE    number of days to extend password after change (1-31)
        00h if no extension required
---v3.x---
 7Bh  5 BYTEs    reserved
---v4.x---
 7Bh    BYTE    storage for first letter of user name when deleted (first
          character is changed to 00h when deleting account)
 7Ch    BYTE    extended privileges
 7Dh  3 BYTEs    reserved

Bitfields for LANtastic privilege bits:
Bit(s)    Description    (Table 1072)
 7    bypass access control lists
 6    bypass queue protection
 5    treat as local process
 4    bypass mail protection
 3    allow audit entry creation
 2    system manager
 0    user cannot change password
--------N-215F88-----------------------------
INT 21 - LANtastic v4.0+ - LOGOUT FROM ALL SERVERS
    AX = 5F88h
Return: CF clear if successful
    CF set on error
        AX = error code
SeeAlso: AX=5F82h
--------N-215F97-----------------------------
INT 21 - LANtastic - COPY FILE
    AX = 5F97h
    CX:DX = number of bytes to copy (FFFFFFFFh = entire file)
    SI = source file handle
    DI = destination file handle
Return: CF clear if successful
        DX:AX = number of bytes copied
    CF set on error
        AX = error code
Note:    copy is performed by server
--------N-215F98-----------------------------
INT 21 - LANtastic - SEND UNSOLICITED MESSAGE
    AX = 5F98h
    DS:SI -> message buffer (see #1073)
Return: CF clear if successful
    CF set on error
        AX = error code
Note:    v4.1- return no errors
SeeAlso: AX=5F99h

Format of LANtastic message buffer:
Offset    Size    Description    (Table 1073)
 00h    BYTE    reserved
 01h    BYTE    message type
        00h general
        01h server warning
        02h-7Fh reserved
        80h-FFh user-defined
 02h 16 BYTEs    ASCIZ destination machine name
 12h 16 BYTEs    ASCIZ server name which user must be logged into
 22h 16 BYTEs    ASCIZ user name
 32h 16 BYTEs    ASCIZ originating machine name (filled in when received)
 42h 80 BYTEs    message text
--------N-215F99-----------------------------
INT 21 - LANtastic - GET LAST RECEIVED UNSOLICITED MESSAGE
    AX = 5F99h
    ES:DI -> messsage buffer (see #1073)
Return: CF clear if successful
    CF set on error
        AX = error code
SeeAlso: AX=5F98h
--------N-215F9A-----------------------------
INT 21 - LANtastic - GET MESSAGE PROCESSING FLAGS
    AX = 5F9Ah
Return: CF clear if successful
        DL = bits describing processing of received messages (see #1074)
    CF set on error
        AX = error code
SeeAlso: AX=5F9Bh,AX=5F9Ch,AX=5F9Dh

Bitfields for unsolicited message processing flags:
Bit(s)    Description    (Table 1074)
 0    beep before message is delivered
 1    deliver message to message service
 2    pop up message automatically (v3+)
--------N-215F9B-----------------------------
INT 21 - LANtastic - SET MESSAGE PROCESSING FLAGS
    AX = 5F9Bh
    DL = bits describing processing for received unsolicited messages
         (see #1074)
Return: CF clear if successful
    CF set on error
        AX = error code
SeeAlso: AX=5F9Ah,AX=5F9Eh
--------N-215F9C-----------------------------
INT 21 - LANtastic v3+ - POP UP LAST RECEIVED MESSAGE
    AX = 5F9Ch
    CX = time to leave on screen in clock ticks
    DH = 0-based screen line on which to place message
Return: CF clear if successful
    CF set on error
        AX = error code (0Bh)
Notes:    the original screen contents are restored when the message is removed
    the message will not appear, and an error will be returned, if the
      screen is in a graphics mode
SeeAlso: AX=5F9Ah
--------N-215F9D-----------------------------
INT 21 - LANtastic v4.1+ - GET REDIRECTOR CONTROL BITS
    AX = 5F9Dh
Return: DL = redirector control bits
        bit 7: set to notify on print job completion
SeeAlso: AX=5F9Ah,AX=5F9Eh
--------N-215F9E-----------------------------
INT 21 - LANtastic v4.1+ - SET REDIRECTOR CONTROL BITS
    AX = 5F9Eh
    DL = redirector control bits (see AX=5F9Dh)
Return: nothing
SeeAlso: AX=5F9Bh,AX=5F9Dh
--------N-215FA0-----------------------------
INT 21 - LANtastic - GET QUEUE ENTRY
    AX = 5FA0h
    BX = queue entry index (0000h is first entry)
    DS:SI -> buffer for queue entry (see #1075)
    ES:DI -> ASCIZ server name in form "\\name"
Return: CF clear if successful
    CF set on error
        AX = error code
    BX = entry index for next queue entry (BX-1 is current index)
SeeAlso: AX=5FA1h,AX=5FA2h

Format of LANtastic queue entry:
Offset    Size    Description    (Table 1075)
 00h    BYTE    status of entry (see #1076)
 01h    DWORD    size of spooled file
 05h    BYTE    type of entry (see #1077)
 06h    BYTE    output control (see #1078)
 07h    WORD    number of copies
 09h    DWORD    sequence number of queue entry
 0Dh 48 BYTEs    pathname of spooled file
 3Dh 16 BYTEs    user who spooled file
 4Dh 16 BYTEs    name of machine from which file was spooled
 5Dh    WORD    date file was spooled (see #1006 at AX=5700h)
 5Fh    WORD    time file was spooled (see #1005 at AX=5700h)
 61h 17 BYTEs    ASCIZ destination device or user name
 72h 48 BYTEs    comment field

(Table 1076)
Values for status of LANtastic queue entry:
 00h    empty
 01h    being updated
 02h    being held
 03h    waiting for despool
 04h    being despooled
 05h    canceled
 06h    spooled file could not be accessed
 07h    destination could not be accessed
 08h    rush job

(Table 1077)
Values for type of LANtastic queue entry:
 00h    printer queue file
 01h    message
 02h    local file
 03h    remote file
 04h    to remote modem
 05h    batch processor file

Bitfields for output control:
Bit(s)    Description    (Table 1078)
 6    don't delete (for mail)
 5    mail file contains voice mail (v3+)
 4    mail message has been read
 3    response has been requested for this mail
--------N-215FA1-----------------------------
INT 21 - LANtastic - SET QUEUE ENTRY
    AX = 5FA1h
    BX = handle of opened queue entry
    DS:SI -> queue entry (see #1075)
Return: CF clear if successful
    CF set on error
        AX = error code
Notes:    the only queue entry fields which may be changed are output control,
      number of copies, destination device, and comment
    the handle in BX is that from a create or open (INT 21/AH=3Ch,3Dh)
      call on the file "\\server\\@MAIL" or "\\server\@name" (for
      printer queue entries)
SeeAlso: AX=5FA0h,AX=5FA2h,AX=5FA9h
--------N-215FA2-----------------------------
INT 21 - LANtastic - CONTROL QUEUE
    AX = 5FA2h
    BL = control command
        00h start despooling (privileged)
        01h halt despooling (privileged)
        02h halt despooling at end of job (privileged)
        03h pause despooler at end of job (privileged)
        04h print single job (privileged)
        05h restart current job (privileged)
        06h cancel the current job
        07h hold queue entry
        08h release a held queue entry
        09h make queue entry a rushed job (privileged)
    CX:DX = sequence number to control (commands 06h-09h)
    DX = physical printer number (commands 00h-05h)
        00h-02h LPT1-LPT3
        03h,04h COM1,COM2
        other    all printers
    ES:DI -> ASCIZ server name in form "\\machine"
Return: CF clear if successful
    CF set on error
        AX = error code
--------N-215FA3-----------------------------
INT 21 - LANtastic v3+ - GET PRINTER STATUS
    AX = 5FA3h
    BX = physical printer number (00h-02h = LPT1-LPT3, 03h-04h = COM1-COM2)
    DS:SI -> buffer for printer status (see #1079)
    ES:DI -> ASCIZ server name in form "\\machine"
Return: CF clear if successful
    CF set on error
        AX = error code
    BX = next physical printer number
Note:    you must be logged in to the specified server

Format of LANtastic printer status:
Offset    Size    Description    (Table 1079)
 00h    BYTE    printer state (see #1080)
 01h    WORD    queue index of print job being despooled
        FFFFh if not despooling--ignore all following fields
 03h    WORD    actual characters per second being output
 05h    DWORD    number of characters actually output so far
 09h    DWORD    number of bytes read from spooled file so far
 0Dh    WORD    copies remaining to print

Bitfields for LANtastic printer state:
Bit(s)    Description    (Table 1080)
 7    printer paused
 0-6    0 printer disabled
    1 will stop at end of job
    2 print multiple jobs
--------N-215FA4-----------------------------
INT 21 - LANtastic v3+ - GET STREAM INFO
    AX = 5FA4h
    BX = 0-based stream index number
    DS:SI -> buffer for stream information (see #1081)
    ES:DI -> ASCIZ machine name in form "\\machine"
Return: CF clear if successful
    CF set on error
        AX = error code
    BX = next stream number
SeeAlso: AX=5FA5h

Format of LANtastic stream information:
Offset    Size    Description    (Table 1081)
 00h    BYTE    queueing of jobs for logical printer (0=disabled,other=enabled)
 01h 11 BYTEs    logical printer resource template (may contain ? wildcards)
--------N-215FA5-----------------------------
INT 21 - LANtastic v3+ - SET STREAM INFO
    AX = 5FA5h
    BX = 0-based stream index number
    DS:SI -> buffer containing stream information (see #1081)
    ES:DI -> ASCIZ machine name in form "\\machine"
Return: CF clear if successful
    CF set on error
        AX = error code
SeeAlso: AX=5FA4h
--------N-215FA7-----------------------------
INT 21 - LANtastic - CREATE USER AUDIT ENTRY
    AX = 5FA7h
    DS:DX -> ASCIZ reason code (max 8 bytes)
    DS:SI -> ASCIZ variable reason string (max 128 bytes)
    ES:DI -> ASCIZ machine name in form "\\machine"
Return: CF clear if successful
    CF set on error
        AX = error code
Note:    you must be logged in to the specified server and have the "U"
      privilege to execute this call
--------N-215FA9-----------------------------
INT 21 - LANtastic v4.1+ - SET EXTENDED QUEUE ENTRY
    AX = 5FA9h
    BX = handle of opened queue entry
    DS:SI -> queue entry (see #1075)
Return: CF clear if successful
    CF set on error
        AX = error code
Note:    functions exactly the same as AX=5FA1h except the spooled filename is
      also set.  This call supports direct despooling.
SeeAlso: AX=5FA1h
--------N-215FB0-----------------------------
INT 21 - LANtastic - GET ACTIVE USER INFORMATION
    AX = 5FB0h
    BX = server login entry index
    DS:SI -> buffer for active user entry (see #1082)
    ES:DI -> ASCIZ machine name in form "\\server"
Return: CF clear if successful
    CF set on error
        AX = error code
    BX = next login index
SeeAlso: AX=5FB2h

Format of LANtastic active user entry:
Offset    Size    Description    (Table 1082)
 00h    WORD    virtual circuit number
 02h    BYTE    login state (see #1083)
 03h    BYTE    last command issued (see #1084)
 04h  5 BYTEs    number of I/O bytes (40-bit unsigned number)
 09h  3 BYTEs    number of server requests (24-bit unsigned)
 0Ch 16 BYTEs    name of user who is logged in
 1Ch 16 BYTEs    name of remote logged in machine
 2Ch    BYTE    extended privileges (v4+???)
        bit 0: user cannot change his password
 2Dh    WORD    time left in minutes (0000h = unlimited) (v4+???)

Bitfields for login state:
Bit(s)    Description    (Table 1083)
 0    fully logged in
 1    remote program load login
 2    user has system manager privileges
 3    user can create audit entries
 4    bypass mail protection
 5    treat as local process
 6    bypass queue protection
 7    bypass access control lists

(Table 1084)
Values for last LANtastic command:
 00h    login
 01h    process termination
 02h    open file
 03h    close file
 04h    create file
 05h    create new file
 06h    create unique file
 07h    commit data to disk
 08h    read file
 09h    write file
 0Ah    delete file
 0Bh    set file attributes
 0Ch    lock byte range
 0Dh    unlock byte range
 0Eh    create subdirectory
 0Fh    remove subdirectory
 10h    rename file
 11h    find first matching file
 12h    find next matching file
 13h    get disk free space
 14h    get a queue entry
 15h    set a queue entry
 16h    control the queue
 17h    return login information
 18h    return link description
 19h    seek on file
 1Ah    get server's time
 1Bh    create audit entry
 1Ch    open file in multitude of modes
 1Dh    change password
 1Eh    disable account
 1Fh    local server file copy
---v3+---
 20h    get username from account file
 21h    translate server's logical path
 22h    make indirect file
 23h    get indirect file contents
 24h    get physical printer status
 25h    get logical print stream info
 26h    set logical print stream info
 27h    get user's account record
---v4+---
 28h    request server shutdown
 29h    cancel server shutdown
 2Ah    stuff server's keyboard
 2Bh    write then commit data to disk
 2Ch    set extended queue entry
 2Dh    terminate user from server
 2Eh    enable/disable logins
 2Fh    flush server caches
 30h    change username
 31h    get extended queue entry
    (same as get queue, but can return named fields blanked)
--------N-215FB1-----------------------------
INT 21 - LANtastic - GET SHARED DIRECTORY INFORMATION
    AX = 5FB1h
    DS:SI -> 64-byte buffer for link description
    ES:DI -> ASCIZ machine and shared directory name in form
         "\\machine\shared-resource"
Return: CF clear if successful
        CX = access control list privileges for requesting user (see #1085)
    CF set on error
        AX = error code

Bitfields for LANtastic access control list:
Bit(s)    Description    (Table 1085)
 4    (I) allow expansion of indirect files
 5    (A) allow attribute changing
 6    (P) allow physical access to device
 7    (E) allow program execution
 8    (N) allow file renaming
 9    (K) allow directory deletion
 10    (D) allow file deletion
 11    (L) allow file/directory lookups
 12    (M) allow directory creation
 13    (C) allow file creation
 14    (W) allow open for write and writing
 15    (R) allow open for read and reading
--------N-215FB2-----------------------------
INT 21 - LANtastic v3+ - GET USERNAME FROM ACCOUNT FILE
    AX = 5FB2h
    BX = username entry index (0 for first)
    DS:SI -> 16-byte buffer for username
    ES:DI -> ASCIZ server name in form "\\machine"
Return: CF clear if successful
    CF set on error
        AX = error code
    BX = next queue entry index
SeeAlso: AX=5FB0h
--------N-215FB3-----------------------------
INT 21 - LANtastic v3+ - TRANSLATE PATH
    AX = 5FB3h
    DS:SI -> 128-byte buffer for ASCIZ result
    ES:DI -> full ASCIZ path, including server name
    DX = types of translation to be performed
        bit 0: expand last component as indirect file
        bit 1: return actual path relative to server's physical disk
Return: CF clear if successful
    CF set on error
        AX = error code
Note:    always expands any indirect files along the path
SeeALso: AX=5FB4h,INT 21/AH=60h
--------N-215FB4-----------------------------
INT 21 - LANtastic v3+ - CREATE INDIRECT FILE
    AX = 5FB4h
    DS:SI -> 128-byte buffer containing ASCIZ contents of indirect file
    ES:DI -> full ASCIZ path of indirect file to create, incl machine name
Return: CF clear if successful
    CF set on error
        AX = error code
Note:    the contents of the indirect file may be any valid server-relative path
SeeAlso: AX=5FB3h,AX=5FB5h
--------N-215FB5-----------------------------
INT 21 - LANtastic v3+ - GET INDIRECT FILE CONTENTS
    AX = 5FB5h
    DS:SI -> 128-byte buffer for ASCIZ indirect file contents
    ES:DI -> full ASCIZ path of indirect file
Return: CF clear if successful
    CF set on error
        AX = error code
SeeAlso: AX=5FB4h
--------N-215FB6-----------------------------
INT 21 - LANtastic v4.1+ - SET AUTO-LOGIN DEFAULTS
    AX = 5FB6h
    ES:DI -> pointer to ASCIZ default user name, immediately followed by
        ASCIZ password
    BL = adapter number to use for default login attempt
        FFh try all valid adapters
        00h-05h try adapter 0-5 explicitly
Return: CF clear if successful
    CF set on error
        AX = error code
Notes:    call with ES:DI -> two nulls to disable auto-login
SeeAlso: AX=5FB7h
--------N-215FB7-----------------------------
INT 21 - LANtastic v4.1+ - GET AUTO-LOGIN DEFAULTS
    AX = 5FB7h
    ES:DI -> pointer to 16-byte buffer to store ASCIZ auto-login user name
Return: CF clear if successful
        DL = adapter number used for default login attempt
        FFh all valid adapters will be tried
        00h-05h specified adapter will be tried explicitly
    CF set on error
        AX = error code
SeeAlso: AX=5F81h,AX=5FB6h
--------N-215FC0-----------------------------
INT 21 - LANtastic - GET TIME FROM SERVER
    AX = 5FC0h
    DS:SI -> time block (see #1086)
    ES:DI -> ASCIZ server name to get time from
Return: CF clear if successful
    CF set on error
        AX = error code
SeeAlso: AH=E7h"Novell"

Format of LANtastic time block:
Offset    Size    Description    (Table 1086)
 00h    WORD    year
 02h    BYTE    day
 03h    BYTE    month
 04h    BYTE    minutes
 05h    BYTE    hour
 06h    BYTE    hundredths of second
 07h    BYTE    second
--------N-215FC8-----------------------------
INT 21 - LANtastic v4.0+ - SCHEDULE SERVER SHUTDOWN
    AX = 5FC8h
    ES:DI -> ASCIZ server name in form "\\machine"
    DS:SI -> ASCIZ reason string (80 characters)
    CX = number of minutes until shutdown (0 = immediate)
    DX = option flags (see #1087)
Return: CF clear if successful
    CF set on error
        AX = error code
SeeAlso: AX=5FC9h

Bitfields for LANtastic option flags:
Bit(s)    Description    (Table 1087)
 0    auto reboot
 1    do not notify users
 2    halt after shutdown
 3    shutdown due to power fail (used by UPS)
 4-7    reserved
 8-14    user definable
 15    reserved
--------N-215FC9-----------------------------
INT 21 - LANtastic v4.0+ - CANCEL SERVER SHUTDOWN
    AX = 5FC9h
    ES:DI -> ASCIZ server name in form "\\machine"
Return: CF clear if successful
    CF set on error
        AX = error code
Note:    you must have the "S" privilege to use this call
SeeAlso: AX=5FC8h
--------N-215FCA-----------------------------
INT 21 - LANtastic v4.0+ - STUFF SERVER KEYBOARD BUFFER
    AX = 5FCAh
    ES:DI -> ASCIZ server name in form "\\machine"
    DS:SI -> ASCIZ string to stuff (128 bytes)
Return: CF clear if successful
    CF set on error
        AX = error code
Note:    you must have the "S" privilege to use this call
    maximum number of characters that can be stuffed is determined by the
      server's RUN BUFFER SIZE.
SeeAlso: INT 16/AH=05h
--------N-215FCB-----------------------------
INT 21 - LANtastic v4.1+ - TERMINATE USER
    AX = 5FCBh
    ES:DI -> ASCIZ server name in form "\\machine"
    DS:SI -> blank-padded username.     A null char = wildcard.
    DS:DX -> blank-padded machine name.  A null char = wildcard.
    CX = minutes until termination (0 = immediate)
Return: CF clear if successful
    CF set on error
        AX = error code
Note:    you must have the "S" privilege to use this call
    you cannot log yourself out using this call
SeeAlso: AX=5F82h
--------N-215FCC-----------------------------
INT 21 - LANtastic v4.1+ - GET/SET SERVER CONTROL BITS
    AX = 5FCCh
    ES:DI -> ASCIZ server name in form "\\machine"
    CX = bit values (value of bits you want to set) (see #1088)
    DX = bit mask (bits you are interested in, 0 = get only) (see #1088)
Return: CF clear if successful
        CX = control bits after call (see #1088)
    CF set on error
        AX = error code
Note:    you must have the "S" privilege to SET, anyone can GET.

Bitfields for control bits:
Bit(s)    Description    (Table 1088)
 0    disable logins
--------N-215FCD-----------------------------
INT 21 - LANtastic v4.1+ - FLUSH SERVER CACHES
    AX = 5FCDh
    ES:DI -> ASCIZ server name in form "\\machine"
Return: CF clear if successful
    CF set on error
        AX = error code
Note:    you must have the "S" privilege to use this call.
--------N-215FD0-----------------------------
INT 21 - LANtastic - GET REDIRECTED PRINTER TIMEOUT
    AX = 5FD0h
Return: CF clear if successful
        CX = redirected printer timeout in clock ticks of 55ms
        0000h if timeout disabled
    CF set on error
        AX = error code
SeeAlso: AX=5FD1h
--------N-215FD1-----------------------------
INT 21 - LANtastic - SET REDIRECTED PRINTER TIMEOUT
    AX = 5FD1h
    CX = printer timeout in clock ticks of 55ms, 0000h to disable timeouts
Return: CF clear if successful
    CF set on error
        AX = error code
SeeAlso: AX=5FD0h
--------N-215FE0-----------------------------
INT 21 C - LANtastic - GET DOS SERVICE VECTOR
    AX = 5FE0h
Return: CF clear if successful
        ES:BX -> current FAR service routine
    CF set on error
        AX = error code
Note:    the service routine is called by the LANtastic redirector whenever DOS
      may safely be called, permitting external TSRs and drivers to hook
      into LANtastic's DOS busy flag checking
SeeAlso: AX=5FE1h,INT 28,INT 2A/AH=84h
--------N-215FE1-----------------------------
INT 21 - LANtastic - SET DOS SERVICE VECTOR
    AX = 5FE1h
    ES:BX -> FAR routine to call when DOS services are available
Return: CF clear if successful
    CF set on error
        AX = error code
Note:    new handler must chain to previous handler as its first action
SeeAlso: AX=5FE0h
--------N-215FE2-----------------------------
INT 21 - LANtastic - GET MESSAGE SERVICE VECTOR
    AX = 5FE2h
Return: CF clear if successful
        ES:BX -> current FAR message service routine
    CF set on error
        AX = error code
SeeAlso: AX=5FE0h,AX=5FE3h
--------N-215FE3-----------------------------
INT 21 - LANtastic - SET MESSAGE SERVICE VECTOR
    AX = 5FE3h
    ES:BX -> FAR routine for processing network messages
Return: CF clear if successful
    CF set on error
        AX = error code
Notes:    handler must chain to previous handler as its first action
    on invocation, ES:BX -> just-received message
SeeAlso: AX=5FE2h
--------D-2160-------------------------------
INT 21 - DOS 3.0+ - "TRUENAME" - CANONICALIZE FILENAME OR PATH
    AH = 60h
    DS:SI -> ASCIZ filename or path
    ES:DI -> 128-byte buffer for canonicalized name
Return: CF set on error
        AX = error code
        02h invalid component in directory path or drive letter only
        03h malformed path or invalid drive letter
        ES:DI buffer unchanged
    CF clear if successful
        AH = 00h or 3Ah (DOS 6.1/6.2 for character device)
        AL = destroyed (00h or 2Fh or 5Ch or last character of current
          directory on drive)
        buffer filled with qualified name of form D:\PATH\FILE.EXT or
          \\MACHINE\PATH\FILE.EXT
Desc:    determine the canonical name of the specified filename or path,
      corresponding to the undocumented TRUENAME command in COMMAND.COM
Notes:    the input path need not actually exist
    letters are uppercased, forward slashes converted to backslashes,
      asterisks converted to appropriate number of question marks, and
      file and directory names are truncated to 8.3 if necessary.  (DR DOS
      3.41 and 5.0 do not expand asterisks)
    '.' and '..' in the path are resolved
    filespecs on local drives always start with "d:", those on network
      drives always start with "\\"
    if path string is on a JOINed drive, the returned name is the one that
      would be needed if the drive were not JOINed; similarly for a
      SUBSTed, ASSIGNed, or network drive letter.    Because of this, it is
      possible to get a qualified name that is not legal under the current
      combination of SUBSTs, ASSIGNs, JOINs, and network redirections
    under DOS 3.3 through 6.00, a device name is translated differently if
      the device name does not have an explicit directory or the directory
      is \DEV (relative directory DEV from the root directory works
      correctly).  In these cases, the returned string consists of the
      unchanged device name and extension appended to the string X:/
      (forward slash instead of backward slash as in all other cases) where
      X is the default or explicit drive letter.
    under MS-DOS 7.0, this call returns the short name for any
      long-filename portions of the provided pathname or filename
    functions which take pathnames require canonical paths if invoked via
      INT 21/AX=5D00h
    supported by OS/2 v1.1 compatibility box
    NetWare 2.1x does not support characters with the high bit set; early
      versions of NetWare 386 support such characters except in this call.
      In addition, NetWare returns error code 3 for the path "X:\"; one
      should use "X:\." instead.
    Novell DOS 7 reportedly has difficulty with non-MS-DOS filenames on
      network drives, and can return "D:" instead of "SERVER/VOLUME"
    for DOS 3.3-6.0, the input and output buffers may be the same, as the
      canonicalized name is built in an internal buffer and copied to the
      specified output buffer as the very last step
    for DR DOS 6.0, this function is not automatically called when on a
      network.  Device drivers reportedly cannot make this call from their
      INIT function.  Using the same pointer for both input and output
      buffers is not supported in the April 1992 and earlier versions of
      DR DOS
    Windows for Workgroups 3.11, Windows95 and even MS-DOS 7.00 only
      return the local drive path; to obtain network paths use
      INT 21/AX=5F02h or INT 21/AX=5F46h instead
    Corel's CORELCDX and MSCDEX without the /S switch return canonical
      names of the form "\\D.\A.\path", where "D" is the CD-ROM drive
      letter and "A" appears to indicate the first physical CD-ROM drive;
      MSCDEX with the /S switch returns a canonical name with embedded
      blanks.  Novell DOS 7 NWCDEX as of the 11/16/94 update returns the
      same canonical path as MSCDEX; earlier revisions returned
      "Cdex.   D:\path", where "D" is the CD-ROM drive letter
    the Windows95 MSCDEX-replacement VxD returns "D:\path", even though the
      MS-DOS 7.00 MSCDEX behaves identically to older versions (above)
SeeAlso: AX=5F02h,AX=5FB3h,AX=7160h/CL=00h,INT 2F/AX=1123h,INT 2F/AX=1221h
--------D-2161-------------------------------
INT 21 - DOS 3.0+ - UNUSED (RESERVED FOR NETWORK USE)
    AH = 61h
Return: AL = 00h
Note:    this function does nothing and returns immediately
--------O-2161--BP6467-----------------------
INT 21 U - OS/2 v1.x FAPI - OS/2 FILE SYSTEM JOIN/SUBST
    AH = 61h
    BP = 6467h ("dg")
    AL = function
        00h list (i.e. get)
        01h add
        02h delete
    BX = drive number
    CX = size of buffer
    SI = type (0002h JOIN, 0003h SUBST)
    ES:DI -> buffer
Return: CF clear if successful
        AX = 0000h
        ES:DI buffer filled, if appropriate
    CF set on error
        AX = error code
Notes:    used by JOIN and SUBST to communicate with the OS/2 file system
    for function 00h (list), the ES:DI buffer is filled with the ASCIZ
      JOIN/SUBST path or an empty string if the drive is not JOINed/SUBSTed
    also supported by OS/2 v2.0+ Virtual DOS Machines
--------D-2162-------------------------------
INT 21 - DOS 3.0+ - GET CURRENT PSP ADDRESS
    AH = 62h
Return: BX = segment of PSP for current process
Notes:    this function does not use any of the DOS-internal stacks and may
      thus be called at any time, even during another INT 21h call
    the current PSP is not necessarily the caller's PSP
    identical to the undocumented AH=51h
SeeAlso: AH=50h,AH=51h
--------U-216262SI1994-----------------------
INT 21 - ENVLOCK - INSTALLATION CHECK
    AX = 6262h
    SI = 1994h
Return: AX = 1994h if installed
        ES = ENVLOCK's resident segment
Notes:    to deactivate ENVLOCK, zero out the byte at ES:[0102h]
Program: ENVLOCK is a TSR by Alexander Yanovsky (aka PC Hawk) that forces
      other TSRs to deallocate their environment when they stay resident
--------D-216300-----------------------------
INT 21 - DOS 2.25 only - GET LEAD BYTE TABLE ADDRESS
    AX = 6300h
Return: CF clear if successful
        DS:SI -> lead byte table (see #1089)
    CF set on error
        AX = error code (01h) (see #1020 at AH=59h/BX=0000h)
Notes:    does not preserve any registers other than SS:SP
    the US version of MS-DOS 3.30 treats this as an unused function,
      setting AL=00h and returning immediately
SeeAlso: AX=6301h,AH=07h,AH=08h,AH=0Bh

Format of double-byte character set lead byte table entry:
Offset    Size    Description    (Table 1089)
 00h  2 BYTEs    low/high ends of a range of leading byte of double-byte chars
 02h  2 BYTEs    low/high ends of a range of leading byte of double-byte chars
    ...
  N   2 BYTEs    00h,00h end flag
--------D-216300-----------------------------
INT 21 - DOS 3.2+ - GET DOUBLE BYTE CHARACTER SET LEAD-BYTE TABLE
    AX = 6300h
Return: AL = error code
        00h successful
        DS:SI -> DBCS table (see #1089)
        all other registers except CS:IP and SS:SP destroyed
        FFh not supported
Notes:    probably identical to AH=63h/AL=00h for DOS 2.25
    the US version of MS-DOS 3.30 treats this as an unused function,
      setting AL=00h and returning immediately, WITHOUT setting DS:SI;
      only the Far East versions of MS-DOS 3.2 and 3.3 supported this call
    the US version of DOS 4.0+ accepts this function, but returns an empty
      list
    IBM DOS 6.1 SYS.COM assumes that CF is set on error
SeeAlso: AX=6300h"DOS 2.25"
--------D-216301-----------------------------
INT 21 - DOS 2.25, DOS 3.2+ - SET KOREAN (HANGEUL) INPUT MODE
    AX = 6301h
    DL = new mode
        00h return only full characters on DOS keyboard input functions
        01h return partially-formed (interim) characters also
Return: AL = status
        00h successful
        FFh invalid mode
Notes:    Novell DOS 7 simply stores DL in the caller's PSP (see #0725 at AH=26h)
    the US version of MS-DOS 3.30 treats this as an unused function,
      setting AL=00h and returning immediately; only the Far East versions
      of MS-DOS 3.2 and 3.3 supported this call
SeeAlso: AH=07h,AH=08h,AH=0Bh,AX=6300h,AX=6302h
--------D-216302-----------------------------
INT 21 - DOS 2.25, DOS 3.2+ - GET KOREAN (HANGEUL) INPUT MODE
    AX = 6302h
Return: AL = status
        00h successful
        DL = current input mode
            00h return only full characters (clears interim flag)
            01h return partial characters (sets interim flag)
        FFh not supported
Notes:    Novell DOS 7 simply reads the value out of the caller's PSP, so it
      can return values other than 00h or 01h if the last call to AX=6301h
      used another value
    the US version of MS-DOS 3.30 treats this as an unused function,
      setting AL=00h and returning immediately, WITHOUT setting DL; only
      the Far East versions of MS-DOS 3.2 and 3.3 supported this call
SeeAlso: AH=07h,AH=08h,AH=0Bh,AX=6300h,AX=6301h
--------v-216303------------------------
INT 21 - VIRUS - "DOS IDLE" - INSTALLATION CHECK
    AX = 6303h
Return: BX = 6303h if resident
SeeAlso: AX=5643h"VIRUS",AX=6304h"VIRUS",AX=9AD5h"VIRUS"
--------v-216304------------------------
INT 21 - VIRUS - "Replicator" - INSTALLATION CHECK
    AX = 6304h
Return: BX = 6304h if resident
SeeAlso: AX=6303h"VIRUS",AX=6969h"VIRUS"
--------D-2164-------------------------------
INT 21 - DOS 3.2+ internal - SET DEVICE DRIVER LOOKAHEAD FLAG
    AH = 64h
    AL = flag
        00h (default) call device driver function 5 (non-dest read)
            before INT 21/AH=01h,08h,0Ah
        nonzero don't call driver function 5
Return: nothing (MS-DOS)
    CF set, AX=error code??? (DR DOS 5.0, which does not support this call)
Notes:    this function is called by the DOS 3.3+ PRINT.COM
    under MS-DOS, this function does not use any of the DOS-internal stacks
      and may thus be called at any time, even during another DOS call
SeeAlso: AH=01h,AH=08h,AH=0Ah,AX=5D06h
--------O-2164--DX0000-----------------------
INT 21 U - OS/2 v2.0+ Virtual DOS Machine - ENABLE AUTOMATIC TITLE SWITCH
    AH = 64h
    DX = 0000h (function number)
    CX = 636Ch (magic value, "cl")
    BX = 0000h (indicates special request)
Note:    if CX is not 636Ch on entry, INT 21/AH=6Ch is invoked, because a bug
      in OS/2 1.x FAPI erroneously called AH=64h instead of AH=6Ch
SeeAlso: AH=64h/DX=0001h,INT 21/AH=4Bh
--------O-2164--DX0001-----------------------
INT 21 U - OS/2 v2.0+ Virtual DOS Machine - SET SESSION TITLE
    AH = 64h
    DX = 0001h (function number)
    CX = 636Ch (magic value, "cl")
    BX = 0000h (indicates special request)
    ES:DI -> new ASCIZ title (max 12 char) or "" to restore default title
Note:    if CX is not 636Ch on entry, INT 21/AH=6Ch is invoked, because a bug
      in OS/2 1.x FAPI erroneously called AH=64h instead of AH=6Ch
SeeAlso: AH=64h/DX=0000h,AH=64h/DX=0002h,INT 15/AH=12h/BH=05h
--------O-2164--DX0002-----------------------
INT 21 U - OS/2 v2.0+ Virtual DOS Machine - GET SESSION TITLE
    AH = 64h
    DX = 0002h (function number)
    CX = 636Ch (magic value, "cl")
    BX = 0000h (indicates special request)
    ES:DI -> 13-byte buffer for current title
Return: buffer filled (single 00h if title never changed)
Note:    if CX is not 636Ch on entry, INT 21/AH=6Ch is invoked, because a bug
      in OS/2 1.x FAPI erroneously called AH=64h instead of AH=6Ch
SeeAlso: AH=64h/DX=0000h,AH=64h/DX=0001h,INT 15/AH=12h/BH=05h
--------O-2164--DX0003-----------------------
INT 21 U - OS/2 v2.1 Virtual DOS Machine - GET LASTDRIVE
    AH = 64h
    DX = 0003h (function number)
    CX = 636Ch (magic value, "cl")
    BX = 0000h (indicates special request)
Return: AL = highest drive supported
Notes:    if CX is not 636Ch on entry, INT 21/AH=6Ch is invoked, because a bug
      in OS/2 1.x FAPI erroneously called AH=64h instead of AH=6Ch
    used by WinOS2
    not supported by OS/2 Warp 3.0, check list of lists instead (see #0968)
SeeAlso: AH=52h
--------O-2164--DX0004-----------------------
INT 21 U - OS/2 v2.1+ Virtual DOS Machine - GET SIZE OF PTDA JFT
    AH = 64h
    DX = 0004h (function number)
    CX = 636Ch (magic value, "cl")
    BX = 0000h (indicates special request)
Return: AX = number of entries in OS/2 JFT for VDM
Notes:    if CX is not 636Ch on entry, INT 21/AH=6Ch is invoked, because a bug
      in OS/2 1.x FAPI erroneously called AH=64h instead of AH=6Ch
    in an OS/2 VDM, the DOS Job File Table in the PSP contains an index
      into the OS/2 JFT in the Per-Task Data Area rather than an SFT index
      because the OS/2 SFT can contain more than 255 entries
--------O-2164--DX0005-----------------------
INT 21 U - OS/2 v2.1+ Virtual DOS Machine - GET SECOND SFT FLAGS WORD
    AH = 64h
    DX = 0005h (function number)
    CX = 636Ch (magic value, "cl")
    BX = 0000h (indicates special request)
    DI = DOS file handle
Return: AX = value of second flags word from OS/2 SFT entry for file
Notes:    if CX is not 636Ch on entry, INT 21/AH=6Ch is invoked, because a bug
      in OS/2 1.x FAPI erroneously called AH=64h instead of AH=6Ch
    the OS/2 SFT has two flags words rather than DOS's one word, and this
      function provides access to the word which is not present in DOS
--------O-2164--DX0006-----------------------
INT 21 U - OS/2 v2.1+ Virtual DOS Machine - UNLOAD DOSKRNL SYMBOLS & LOAD PROGR
    AH = 64h
    DX = 0006h (function number)
    CX = 636Ch (magic value, "cl")
    BX = 0000h (indicates special request)
    ES:DI -> ASCIZ filespec
    DS = base address for loading
Notes:    if CX is not 636Ch on entry, INT 21/AH=6Ch is invoked, because a bug
      in OS/2 1.x FAPI erroneously called AH=64h instead of AH=6Ch
    this function is only supported by the kernel debugging version of
      OS2KRNL
--------O-2164--DX0007-----------------------
INT 21 U - OS/2 v2.1+ Virtual DOS Machine - GET WinOS2 CALL GATE ADDRESS
    AH = 64h
    DX = 0007h (function number)
    CX = 636Ch (magic value, "cl")
    BX = 0000h (indicates special request)
Return: AX = call gate address
Notes:    if CX is not 636Ch on entry, INT 21/AH=6Ch is invoked, because a bug
      in OS/2 1.x FAPI erroneously called AH=64h instead of AH=6Ch
    used by WinOS2 to make direct calls to OS2KRNL, bypassing the overhead
      of DOSKRNL
--------O-2164--DX0008-----------------------
INT 21 U - OS/2 v2.1+ Virtual DOS Machine - GET LOADING MESSAGE
    AH = 64h
    DX = 0008h (function number)
    CX = 636Ch (magic value, "cl")
    BX = 0000h (indicates special request)
Return: DS:DX -> '$'-terminated message "Loading.  Please wait."
Notes:    if CX is not 636Ch on entry, INT 21/AH=6Ch is invoked, because a bug
      in OS/2 1.x FAPI erroneously called AH=64h instead of AH=6Ch
    this function permits National Language Support for the initial message
      displayed while WinOS2 starts a full-screen session
--------O-2164--CX636C-----------------------
INT 21 U - OS/2 v2.1+ Virtual DOS Machine - OS/2 API support
    AH = 64h
    CX = 636Ch ("cl")
    BX = API ordinal (see #1090)
    other registers as appropriate for API call
Return: as appropriate for API call
SeeAlso: AH=64h/BX=0025h,AH=64h/BX=00B6h,AH=64h/BX=00CBh

(Table 1090)
Values for OS/2 API ordinal:
 0025h    DOS32StartSession
 0082h    DosGetCP
 00B6h    DosQFSAttach
 00BFh    DosEditName
 00CBh    DosForceDelete
 0144h    Dos32CreateEventSem
 0145h    Dos32OpenEvenSem
 0146h    Dos32CloseEventSem
 0147h    Dos32ResetEventSem
 0148h    Dos32PostEventSem
 0149h    Dos32WaitEventSem
 014Ah    Dos32QueryEventSem
 014Bh    Dos32CreateMutexSem
 014Ch    Dos32OpenMutexSem
 014Dh    Dos32CloseMutexSem
 014Eh    Dos32RequestMutexSem
 014Fh    Dos32ReleaseMutexSem
 0150h    Dos32QueryMutexSem
 0151h    Dos32CreateMuxWaitSem
 0152h    Dos32OpenMuxWaitSem
 0153h    Dos32CloseMuxWaitSem
 0154h    Dos32WaitMuxWaitSem
 0155h    Dos32AddMuxWaitSem
 0156h    Dos32DeleteMuxWaitSem
 0157h    Dos32QueryMuxWaitSem
--------O-2164--BX0025-----------------------
INT 21 U - OS/2 v2.1+ Virtual DOS Machine - OS/2 API DOS32StartSession
    AH = 64h
    BX = 0025h (API ordinal)
    CX = 636Ch ("cl")
    DS:SI -> STARTDATA structure (see #1091)
Return: AX = return code
SeeAlso: AH=64h/CX=636Ch,AH=64h/BX=00B6h

Format of OS/2 Virtual DOS Machine STARTDATA structure:
Offset    Size    Description    (Table 1091)
 00h    WORD    length of structure (must be 0018h,001Eh,0020h,0032h,or 003Ch)
 02h    WORD    relation of new process to caller (00h independent, 01h child)
 04h    WORD    fore/background (00h foreground, 01h background)
 06h    WORD    trace options (00h-02h, 00h = no trace)
 08h    DWORD    pointer to ASCIZ program title (max 62 chars) or 0000h:0000h
 0Ch    DWORD    pointer to ASCIZ program name (max 128 chars) or 0000h:0000h
 10h    DWORD    pointer to ASCIZ program args (max 144 chars) or 0000h:0000h
 14h    DWORD    "TermQ" (currently reserved, must be 00000000h)
 18h    DWORD    pointer to environment (max 486 bytes) or 0000h:0000h
 1Ch    WORD    inheritance (00h or 01h)
 1Eh    WORD    session type
        00h OS/2 session manager determines type (default)
        01h OS/2 full-screen
        02h OS/2 window
        03h PM
        04h VDM full-screen
        07h VDM window
 20h    DWORD    pointer to ASCIZ icon filename (max 128 chars) or 0000h:0000h
 24h    DWORD    "PgmHandle" (currently reserved, must be 00000000h)
 28h    WORD    "PgmControl"
 2Ah    WORD    initial column
 2Ch    WORD    initial row
 2Eh    WORD    initial width
 30h    WORD    initial height
 32h    WORD    reserved (0)
 34h    DWORD    "ObjectBuffer" (currently reserved, must be 00000000h)
 38h    DWORD    "ObjectBufferLen" (currently reserved, must be 00000000h)
--------O-2164--BX00B6-----------------------
INT 21 U - OS/2 v2.1+ Virtual DOS Machine - OS/2 API DosQFSAttach
    AH = 64h
    BX = 00B6h (API ordinal)
    CX = 636Ch (magic value "cl")
    DS = user's data segment
    ES:DI -> FSQAttachStruc (see #1092)
Return: CF set on error
        AX = error code (see #1020 at AH=59h/BX=0000h)
    CF clear if successful
        AX = 0000h
        data buffer filled
SeeAlso: AH=64h/CX=636Ch

Format of OS/2 Virtual DOS Machine FSQAttachStruc:
Offset    Size    Description    (Table 1092)
 00h    DWORD    reserved
 04h    DWORD    pointer to the offset of the data buffer length
 08h    DWORD    pointer to the offset of the data buffer
 0Ch    WORD    FSA Info level
 0Eh    WORD    ordinal index into table
 10h    DWORD    pointer to the offset of the device name
Notes:    The segment value of the buffer, buffer length, and device
      name MUST all be the same.  It is defined on entry in the DS
      register.  The details of each info level are defined in the
      OS/2 CP Reference.
--------O-2164--BX00CB-----------------------
INT 21 U - OS/2 v2.1+ Virtual DOS Machine - OS/2 API DosForceDelete
    AH = 64h
    BX = 00CBh (API ordinal)
    CX = 636Ch (magic value "cl")
    DS:DX -> ASCIZ filename
Return: CF clear if successful
        AX destroyed
    CF set on error
        AX = error code (02h,03h,05h) (see #1020 at AH=59h/BX=0000h)
Desc:    delete a file without saving it to the undelete directory
SeeAlso: AH=41h,AH=64h/CX=636Ch
--------D-2165-------------------------------
INT 21 - DOS 3.3+ - GET EXTENDED COUNTRY INFORMATION
    AH = 65h
    AL = info ID
        01h get general internationalization info
        02h get pointer to uppercase table
        04h get pointer to filename uppercase table
        05h get pointer to filename terminator table
        06h get pointer to collating sequence table
        07h (DOS 4.0+) get pointer to Double-Byte Character Set table
    BX = code page (FFFFh=global code page) (see #1099)
    DX = country ID (FFFFh=current country)
    ES:DI -> country information buffer (see #1093)
    CX = size of buffer (>= 5)
Return: CF set on error
        AX = error code (see #1020 at AH=59h/BX=0000h)
    CF clear if successful
        CX = size of country information returned
        ES:DI -> country information
Notes:    AL=05h appears to return same info for all countries and codepages; it
      has been documented for DOS 5+, but was undocumented in earlier
      versions
    NLSFUNC must be installed to get info for countries other than the
      default
    subfunctions 02h and 04h are identical under OS/2
SeeAlso: AH=38h,AH=70h"MS-DOS 7",INT 2F/AX=1401h,INT 2F/AX=1402h
SeeAlso: INT 2F/AX=14FEh

Format of country information:
Offset    Size    Description    (Table 1093)
 00h    BYTE    info ID
---if info ID = 01h---
 01h    WORD    size
 03h    WORD    country ID (see #0747 at AH=38h)
 05h    WORD    code page (see #1099)
 07h 34 BYTEs    country-dependent info (see #0746 at AH=38h)
---if info ID = 02h---
 01h    DWORD    pointer to uppercase table (see #1094)
---if info ID = 04h---
 01h    DWORD    pointer to filename uppercase table (see #1095)
---if info ID = 05h---
 01h    DWORD    pointer to filename character table (see #1096)
---if info ID = 06h---
 01h    DWORD    pointer to collating table (see #1097)
---if info ID = 07h (DOS 4.0+)---
 01h    DWORD    pointer to DBCS lead byte table (see #1098)
SeeAlso: #3320

Format of uppercase table:
Offset    Size    Description    (Table 1094)
 00h    WORD    table size
 02h 128 BYTEs    uppercase equivalents (if any) of chars 80h to FFh
SeeAlso: #1093,#1095

Format of filename uppercase table:
Offset    Size    Description    (Table 1095)
 00h    WORD    table size
 02h 128 BYTEs    uppercase equivalents (if any) of chars 80h to FFh
SeeAlso: #1093,#1094

Format of filename terminator table:
Offset    Size    Description    (Table 1096)
 00h    WORD    table size (not counting this word)
 02h    BYTE    ??? (01h for MS-DOS 3.30-6.00)
 03h    BYTE    lowest permissible character value for filename
 04h    BYTE    highest permissible character value for filename
 05h    BYTE    ??? (00h for MS-DOS 3.30-6.00)
 06h    BYTE    first excluded character in range \ all characters in this
 07h    BYTE    last excluded character in range  / range are illegal
 08h    BYTE    ??? (02h for MS-DOS 3.30-6.00)
 09h    BYTE    number of illegal (terminator) characters
 0Ah  N BYTEs    characters which terminate a filename:    ."/\[]:|<>+=;,
Note:    partially documented for DOS 5+, but undocumented for earlier versions
SeeAlso: #1093

Format of collating table:
Offset    Size    Description    (Table 1097)
 00h    WORD    table size
 02h 256 BYTEs    values used to sort characters 00h to FFh
SeeAlso: #1093

Format of DBCS lead byte table:
Offset    Size    Description    (Table 1098)
 00h    WORD    length
 02h 2N BYTEs    start/end for N lead byte ranges
    WORD    0000h    (end of table)
SeeAlso: #1093
--------D-2165-------------------------------
INT 21 - DOS 4.0+ - COUNTRY-DEPENDENT CHARACTER CAPITALIZATION
    AH = 65h
    AL = function
        20h capitalize character
        DL = character to capitalize
        Return: DL = capitalized character
        21h capitalize string
        DS:DX -> string to capitalize
        CX = length of string
        22h capitalize ASCIZ string
        DS:DX -> ASCIZ string to capitalize
Return: CF set on error
        AX = error code (see #1020 at AH=59h/BX=0000h)
    CF clear if successful
Note:    these calls have been documented for DOS 5+, but were undocumented in
      DOS 4.x.
--------D-216523-----------------------------
INT 21 U - DOS 4.0+ - DETERMINE IF CHARACTER REPRESENTS YES/NO RESPONSE
    AX = 6523h
    DL = character
    DH = second character of double-byte character (if applicable)
Return: CF set on error
    CF clear if successful
        AX = type
        00h no
        01h yes
        02h neither yes nor no
Note:    supported by Novell DOS 7, though prior to Update 14, the results
      depended on the kernel variant rather than the COUNTRY= setting
--------D-2165-------------------------------
INT 21 U - DOS 4.0+ internal - COUNTRY-DEPENDENT FILENAME CAPITALIZATION
    AH = 65h
    AL = function
        A0h capitalize filename character
        DL = character to capitalize
        Return: DL = capitalized character
        A1h capitalize counted filename string
        DS:DX -> filename string to capitalize
        CX = length of string
        A2h capitalize ASCIZ filename
        DS:DX -> ASCIZ filename to capitalize
Return: CF set on error
        AX = error code (see #1020 at AH=59h/BX=0000h)
    CF clear if successful
Note:    nonfunctional in MS-DOS 4.00 through 6.00 due to a bug (the code sets a
      pointer depending on the high bit of AL, but doesn't clear the
      bit before branching by function number).  Supported and
      functional(!) in Novell DOS 7 (Update 15)
--------D-216601-----------------------------
INT 21 - DOS 3.3+ - GET GLOBAL CODE PAGE TABLE
    AX = 6601h
Return: CF set on error
        AX = error code (see #1020 at AH=59h/BX=0000h)
    CF clear if successful
        BX = active code page (see #1099)
        DX = system code page (see #1099)
SeeAlso: AX=6602h
--------D-216602-----------------------------
INT 21 - DOS 3.3+ - SET GLOBAL CODE PAGE TABLE
    AX = 6602h
    BX = active code page (see #1099)
    DX = system code page (active page at boot time)
Return: CF set on error
        AX = error code (see #1020 at AH=59h/BX=0000h)
    CF clear if successful
        AX = EB41h (Novell NWDOS v7.0 when NLSFUNC not installed and
          request was for previously-active code page)
SeeAlso: AX=6601h,INT 2F/AX=14FFh

(Table 1099)
Values for code page:
 437    US
 850    Multilingual
 852    Slavic/Latin II (DOS 5+)
 857    Turkish
 860    Portugal
 861    Iceland
 863    Canada (French)
 865    Norway/Denmark

Format of DOS .CPI (Code Page Information) file header:
Offset    Size    Description    (Table 1100)
 00h    BYTE    ID tag
        FFh FONT file (Standard for generic display or
              printer font files used by MS-DOS, PC-DOS, DR DOS
              and Novell DOS)
        7Fh DRFONT file (Used by DR DOS 6.0 / Novell DOS 7 for
              enhanced & compressed display font files. DR DOS 6.0
              and Novell DOS 7 still support the standard FONT
              files, thus allowing leaning of .CPI files from
              MS-DOS to DR DOS / Novell DOS!)
 01h  7 BYTEs    ID string
        "FONT    " = FONT file (Standard for display or printer)
        "DRFONT " = DRFONT file (Enhanced compressed format used
                by DR DOS 6.0 / Novell DOS 7 for display fonts)
 08h  8 BYTEs    reserved (0)
 10h    WORD    number of pointers (1)
 12h    BYTE    type of pointers (1)
 13h    DWORD    pointer to file offset of FontInfoHeader
        (Generally pointing to the byte just after FontFileHeader,
             that is 0000h:0017h. Due to extra data at offset 17h, this
             value has changed with DR DOS 6.0 / Novell DOS 7 DRFONTs!
             "MS-DOS 4.0 programmers reference" claimed word offset
             +15h as an endmarker (0000h), but actually it is the
             High-Word of the pointer.)
--- Extended FontFileHeader with DR DOS 6.0 / Novell DOS 7 DRFONTs: ---
 17h    BYTE    number of fonts per codepage supported by this file
             (N=4 with both DR DOS 6.0 / Novell DOS 7 DRFONT files)
 18h  N    BYTEs    cellsize (Height) of fonts 1..N
        the cellsize corresponds with the character boxes height,
          but is also the count of bytes used for each of the
          characters inside the font data (as currently all fonts
          are organized heightx8 and 8 pixel width is just one byte).
 var  N DWORDs    file offsets of DisplayFontData.

Format of DOS .CPI file Font Information Header:
Offset    Size    Description    (Table 1101)
 00h    WORD    number of codepage entries
    var    N codepage entry headers (see #1102)
SeeAlso: #1100

Format of DOS .CPI file CodePage Entry Header:
Offset    Size    Description    (Table 1102)
 00h    WORD    size of this header (normally 1Ch)
 02h    DWORD    offset of next entry, or 0000h:0000h or FFFFh:FFFFh if last
        (if a valid "next" pointer but all of the fonts indicated in
          the .CPI header have been processed, this field normally
          points at an optional text area at the end of the .CPI file
          containing copyright information)
 06h    WORD    device type
        01h display (FONT or DRFONT)
        02h printer (FONT)
 08h  8 BYTEs    blank-padded device name string
 10h    WORD    code page (see #1099)
 12h  3 WORDs    reserved (0)
 18h    DWORD    pointer to Font Data Header (see #0132)
        normally immediately follows this header
SeeAlso: #1100

Format of DOS .CPI file Font Data Header:
Offset    Size    Description    (Table 1103)
 00h    WORD    record type
        0001h FONT
        0002h DRFONT (DR-DOS 6.0/Novell DOS 7 display font)
 02h    WORD    number of fonts
 04h    WORD    length of font data (display fonts)
        ??? (printer fonts)
 06h    var    font data (#fonts * fontlength) bytes
SeeAlso: #1100

Format of DOS .CPI file ScreenFONT Header:
Offset    Size    Description    (Table 1104)
 00h  6 BYTEs    display-font header (see #1106)
 06h    var    display font data
SeeAlso: #1100

Format of .CPI file DRFONT Header:
Offset    Size    Description    (Table 1105)
 00h 6N BYTEs    DisplayFONT headers for N fonts (see #1106)
      M WORDs    character index table for cell offsets in font data
        currently 256 words in length
SeeAlso: #1100

Format of .CPI file DisplayFONT header:
Offset    Size    Description    (Table 1106)
 00h    BYTE    height of character cell
 01h    BYTE    width of character cell (currently always 08h)
 02h    BYTE    aspect ratio (height) (currently 00h, unused)
 03h    BYTE    aspect ratio (width) (currently 00h, unused)
 04h    WORD    number of characters per font (256)
SeeAlso: #1100

Format of .CPI file PrinterFONT header:
Offset    Size    Description    (Table 1107)
 00h    WORD    type of printer
        0001h (4201.CPI, 1050.CPI, EPS.CPI)
        0002h (4208.CPI, 5202.CPI, PPDS.CPI)
 02h    WORD    bytes per hardware/download codepage-select escape sequence
        (max 31, typically 12)
 04h  N BYTEs    escape sequence to select hardware codepage
      N BYTEs    escape sequence to select download codepage
    var    download data for printer font (including escape sequence to
          transfer data)
SeeAlso: #1100
--------D-2167-------------------------------
INT 21 - DOS 3.3+ - SET HANDLE COUNT
    AH = 67h
    BX = size of new file handle table for process
Return: CF clear if successful
    CF set on error
        AX = error code (see #1020 at AH=59h/BX=0000h)
Desc:    adjust the size of the per-process open file table, thus raising or
      lowering the limit on the number of files the caller can open
      simultaneously
Notes:    if BX <= 20, no action is taken if the handle limit has not yet been
      increased, and the table is copied back into the PSP if the limit
      is currently > 20 handles
    for file handle tables of > 20 handles, DOS 3.30 never reuses the
      same memory block, even if the limit is being reduced; this can lead
      to memory fragmentation as a new block is allocated and the existing
      one freed
    only the first 20 handles are copied to child processes in DOS 3.3-6.0
    increasing the file handles here will not, in general, increase the
      number of files that can be opened using the runtime library of a
      high-level language such as C
    Novell DOS 7 reportedly terminates the calling program if the JFT is
      being reduced in size and there are any open file handles beyond
      the portion of the JFT being retained
BUGS:    the original release of DOS 3.30 allocates a full 64K for the handle
      table on requests for an even number of handles
    DR DOS 3.41 and 5.0 will lose track of any open file handles beyond
      the portion of the JFT retained after the call; MS-DOS will indicate
      error 04h if any of the JFT entries to be removed are open
SeeAlso: AH=26h,AH=86h
--------D-2168-------------------------------
INT 21 - DOS 3.3+ - "FFLUSH" - COMMIT FILE
    AH = 68h
    BX = file handle
Return: CF clear if successful
        all data still in DOS disk buffers is written to disk immediately,
          and the file's directory entry is updated
    CF set on error
        AX = error code (see #1020 at AH=59h/BX=0000h)
SeeAlso: AX=5D01h,AH=6Ah,INT 2F/AX=1107h
--------D-2169-------------------------------
INT 21 U - DOS 4.0+ internal - GET/SET DISK SERIAL NUMBER
    AH = 69h
    AL = subfunction
        00h get serial number
        01h set serial number
    BL = drive (0=default, 1=A, 2=B, etc)
    BH = info level (00h only for DOS; OS/2 allows other levels)
    DS:DX -> disk info (see #1108)
Return: CF set on error
        AX = error code (see #1020 at AH=59h/BX=0000h)
    CF clear if successful
        AX destroyed
        (AL = 00h) buffer filled with appropriate values from extended BPB
        (AL = 01h) extended BPB on disk set to values from buffer
Notes:    does not generate a critical error; all errors are returned in AX
    error 0005h given if no extended BPB on disk
    does not work on network drives (error 0001h)
    buffer after first two bytes is exact copy of bytes 27h thru 3Dh of
      extended BPB on disk
    this function is supported under Novell NetWare versions 2.0A through
      3.11; the returned serial number is the one a DIR would display,
      the volume label is the NetWare volume label, and the file system
      is set to "FAT16".
    this function is not supported by Novell DOS 7 through Update 13, but
      Personal NetWare 1.0 does support this function
    the serial number is computed from the current date and time when the
      disk is created; the first part is the sum of the seconds/hundredths
      and month/day, the second part is the sum of the hours/minutes and
      year
    the volume label which is read or set is the one stored in the extended
      BPB on disks formatted with DOS 4.0+, rather than the special root
      directory entry used by the DIR command in COMMAND.COM (use AH=11h
      to find that volume label)
SeeAlso: AX=440Dh"DOS 3.2+"

Format of disk info:
Offset    Size    Description    (Table 1108)
 00h    WORD    0000h (info level)
 02h    DWORD    disk serial number (binary)
 06h 11 BYTEs    volume label or "NO NAME    " if none present
 11h  8 BYTEs    (AL=00h only) filesystem type (see #1109)

(Table 1109)
Values for filesystem type:
 "FAT12      "    12-bit FAT
 "FAT16      "    16-bit FAT
 "CDROM      "    High-Sierra CD-ROM filesystem
 "CD001      "    ISO 9660 CD-ROM filesystem
 "CDAUDIO "    audio CD
SeeAlso: #1108
--------O-2169-------------------------------
INT 21 - DR DOS 5.0 - NULL FUNCTION
    AH = 69h
Return: AL = 00h
SeeAlso: AH=18h
--------v-216969-----------------------------
INT 21 - VIRUS - "Rape-747" - INSTALLATION CHECK
    AX = 6969h
Return: AX = 0666h if resident
SeeAlso: AX=58CCh,AX=6304h"VIRUS",AH=76h"VIRUS"
--------d-2169FFDX0000-----------------------
INT 21 U - CUBIT v4.00 - GET CUBIT INT 21 HANDLER
    AX = 69FFh
    DX = 0000h
    BX = CB00h (magic value)
Return: ES:BX -> CUBITR.EXE handler for INT 21
Note:    the installation check consists of testing that the first eight bytes
      at the returned interrupt handler are EBh 07h "CUBITR" (a short
      jump around the signature followed by the signature); the byte
      following the signature (i.e. ES:[BX+8]) indicates whether CUBITR
      is active (01h) or disabled (00h)
SeeAlso: AX=69FFh/DX=CFBFh
Index:    installation check;CUBIT
--------d-2169FFDXCFBF-----------------------
INT 21 U - CUBIT v4.00 - UNINSTALL
    AX = 69FFh
    DX = CFBFh
    CX = EFCFh
    BX = CB00h (magic value)
Return: ES:BX -> CUBITR.EXE handler for INT 21
    CX = status
        2020h successful
        2222h failed
Note:    if DX is neither 0000h nor CFBFh on entry, some other code is executed
SeeAlso: AX=69FFh/DX=0000h
--------D-216A-------------------------------
INT 21 U - DOS 4.0+ - COMMIT FILE
    AH = 6Ah
    BX = file handle
Return: CF clear if successful
        AH = 68h
    CF set on error
        AX = error code (06h) (see #1020 at AH=59h/BX=0000h)
Note:    identical to AH=68h in DOS 5.0-6.0; not known whether this is the case
      in DOS 4.x
SeeAlso: AH=68h
--------D-216B-------------------------------
INT 21 U - DOS 4.0 internal - IFS IOCTL
    AH = 6Bh
    AL = subfunction
        00h ???
        DS:SI -> Current Directory Structure???
        CL = drive (1=A:)
        01h ???
        DS:SI -> ???
        CL = file handle???
        02h ???
        DS:SI -> Current Directory Structure???
        DI = ???
        CX = drive (1=A:)
Return: CF set on error
        AX = error code (see #1020 at INT 21/AH=59h/BX=0000h)
    CF clear if successful
Note:    passed through to INT 2F/AX=112Fh with AX on top of stack
SeeAlso: AH=6Bh"DOS 5",INT 2F/AX=112Fh
--------D-216B-------------------------------
INT 21 U - DOS 5+ - NULL FUNCTION
    AH = 6Bh
Return: AL = 00h
Note:    this function does nothing and returns immediately
SeeAlso: AH=6Bh"DOS 4"
--------D-216C00-----------------------------
INT 21 - DOS 4.0+ - EXTENDED OPEN/CREATE
    AX = 6C00h
    BL = open mode as in AL for normal open (see also AH=3Dh)
        bit 7: inheritance
        bits 4-6: sharing mode
        bit 3 reserved
        bits 0-2: access mode
        100 read-only, do not modify file's last-access time (DOS 7.0)
    BH = flags
        bit 6 = auto commit on every write (see also AH=68h)
        bit 5 = return error rather than doing INT 24h
        bit 4 = (FAT32) extended size (>= 2GB)
    CX = create attribute (see #1111)
    DL = action if file exists/does not exist (see #1112)
    DH = 00h (reserved)
    DS:SI -> ASCIZ file name
Return: CF set on error
       AX = error code (see #1020 at AH=59h/BX=0000h)
    CF clear if successful
       AX = file handle
       CX = status (see #1110)
Notes:    the PC LAN Program only supports existence actions (in DL) of 01h,
      10h with sharing=compatibility, and 12h
    DR DOS reportedly does not support this function and does not return
      an "invalid function call" error when this function is used.
    the documented bits of BX are stored in the SFT when the file is opened
      (see #0982,#0983)
BUG:    this function has bugs (at least in DOS 5.0 and 6.2) when used with
      drives handled via the network redirector (INT 2F/AX=112Eh):
        - CX (attribute) is not passed to the redirector if DL=11h,
        - CX does not return the status, it is returned unchanged because
          DOS does a PUSH CX/POP CX when calling the redirector.
SeeAlso: AH=3Ch,AH=3Dh,AX=6C01h,AH=71h,INT 2F/AX=112Eh

(Table 1110)
Values for extended open function status:
 01h    file opened
 02h    file created
 03h    file replaced

Bitfields for file create attribute:
Bit(s)    Description    (Table 1111)
 6-15    reserved
 5    archive
 4    reserved
 3    volume label
 2    system
 1    hidden
 0    readonly

Bitfields for action:
Bit(s)    Description    (Table 1112)
 7-4    action if file does not exist
    0000 fail
    0001 create
 3-0    action if file exists
    0000 fail
    0001 open
    0010 replace/open
--------O-216C01-----------------------------
INT 21 U - OS/2 v2.0 - "DosOpen2"
    AX = 6C01h
    BL = open mode as in AL for normal open (see also AH=3Dh)
        bit 7: inheritance
        bits 4-6: sharing mode
        bit 3 reserved
        bits 0-2: access mode
    BH = flags
        bit 6 = auto commit on every write (see also AH=68h)
        bit 5 = return error rather than doing INT 24h
    CX = create attribute (see #1111)
    DL = action if file exists/does not exist (see #1112)
    DH = 00h (reserved)
    DS:SI -> ASCIZ file name
    ES:DI -> EAOP structure
Return: CF set on error
       AX = error code (see #1020 at AH=59h/BX=0000h)
    CF clear if successful
       AX = file handle
       CX = status (see #1110)
Note:    this function is virtually identical to AX=6C00h, but supports OS/2's
      extended attributes
SeeAlso: AX=5704h,AX=6C00h,AH=6Fh"OS/2"
--------D-216D-------------------------------
INT 21 U - DOS 5+ ROM - FIND FIRST ROM PROGRAM
    AH = 6Dh
    DS:DX -> ASCIZ program name (may contain wildcrds)
Return: CF clear if found
        Disk Transfer Area filled with ROM search structure (see #1113)
    CF set if not found
        AX = error code
        0002h name not found in ROM
        0003h name contains colon or backslash
    ---if not supported (DOS <5, MS-DOS 5+ non-ROM versions)---
    AL = 00h
Notes:    the '*' wildcard matches all remaining characters in a ROM program's
      name; any following characters in the search mask are ignored up to
      another asterisk, which must be matched by an asterisk in the
      found program's name.
    the search mask and program names may contain multiple periods
SeeAlso: AH=1Ah,AH=4Eh,AH=6Eh,AX=6F00h,AX=6F02h

Format of ROM search structure:
Offset    Size    Description    (Table 1113)
 00h 13 BYTEs    ASCIZ name of found ROM program
 0Dh    DWORD    address at which to resume search (do not modify)
 11h    var    ASCIZ search mask passed in (do not modify)
--------O-216D-------------------------------
INT 21 U - OS/2 v1.x FAPI - "DosMkDir2"
    AH = 6Dh
    ???
Return: ???
Desc:    create a new directory, with extended attribute information
Note:    also supported by OS/2 v2.0+ Virtual DOS Machines
BUG:    does not work under OS/2 v2.0 because MVDM does not translate the
      real-mode segment pointer in the Extended Attribute structure
      (see #1013) into a protected-mode selector; use AH=39h followed by
      AX=5703h instead
SeeAlso: AH=39h,AX=5702h"OS/2",AX=5703h"OS/2"
--------O-216D-------------------------------
INT 21 U - Novell DOS 7 - NOP
    AH = 6Dh
Return: AX = 0000h
Note:    this function invokes the same code as other NOP functions such as
      AH=18h and AH=61h
--------D-216E-------------------------------
INT 21 U - DOS 5+ ROM - FIND NEXT ROM PROGRAM
    AH = 6Eh
    Disk Transfer Area contains result of previous FindFirst ROM
      (see AH=6Dh)
Return: CF clear if found
        Disk Transfer Area filled with updated ROM search structure
          (see #1113)
    CF set if not found
        AX = 0012h (no more matches)
    ---if not supported (DOS <5, MS-DOS 5+ non-ROM versions)---
    AL = 00h
SeeAlso: AH=4Fh,AH=6Dh
--------O-216E-------------------------------
INT 21 U - OS/2 v1.x FAPI - "DosEnumAttrib"
    AH = 6Eh
    DS:SI -> parameter packet (see #1114)
Return: CF clear if successful
        AX = 0000h
        DS:SI buffer updated
    CF set on error
        AX = error code
Note:    also supported by OS/2 v2.0+ Virtual DOS Machines
SeeAlso: AX=5703h,AH=6Fh"OS/2",INT 2F/AX=112Dh

Format of OS/2 DosEnumAttrib parameter packet:
Offset    Size    Description    (Table 1114)
 00h    DWORD    reserved (0)
 04h    DWORD    info level (always 00000001h)
 08h    DWORD    (call) number of entries requested
        (ret) actual number of entries returned
 0Ch    DWORD    length of buffer
 10h    DWORD    pointer to buffer for results
 14h    DWORD    number of first entry to return
 18h    DWORD    -> file handle or ASCIZ pathname
 1Ch    WORD    flag: 00h = previous field is file handle, 01h = pathname
--------D-216F00-----------------------------
INT 21 U - DOS 5+ ROM - GET ROM SCAN START ADDRESS
    AX = 6F00h
Return: CF clear
    AL = 00h
        BX = current ROM scan starting segment if function supported
SeeAlso: AH=6Dh,AX=6F01h,AX=6F02h
--------O-216F00-----------------------------
INT 21 U - OS/2 v1.x FAPI - "DosQMaxEASize" - GET MAXIMUM SIZE OF EXTENDED ATTR
    AX = 6F00h
    DS:SI -> DWORD buffer for maximum size of an extended attribute
Return: CF clear if successful
        AX = 0000h
        buffer filled
    CF set on error
        AX = error code
Note:    also supported by OS/2 v2.0+ Virtual DOS Machines
SeeAlso: AX=5703h,AX=6C01h,AH=6Eh"OS/2"
--------D-216F01-----------------------------
INT 21 U - DOS 5+ ROM - SET ROM SCAN START ADDRESS
    AX = 6F01h
    BX = new ROM scan starting address
Return: CF clear
    AL = 00h
SeeAlso: AX=6F00h,AX=6F03h
--------D-216F02-----------------------------
INT 21 U - DOS 5+ ROM - GET EXCLUSION REGION LIST
    AX = 6F02h
    ES:BX -> buffer for exclusion region list (see #1115)
Return: CF clear
    AL = 00h
    ES:BX = 0000h:0000h on error, unchanged if buffer filled
Note:    for DOS versions which do not support this function, the return value
      is AL=00h, CF unchanged, ES:BX unchanged, and the ES:BX buffer
      unchanged
SeeAlso: AX=6F00h,AX=6F03h

Format of ROM exclusion region list:
Offset    Size    Description    (Table 1115)
 00h    WORD    number of entries
 02h 2N WORDs    start/end segments of N excluded regions
--------D-216F03-----------------------------
INT 21 U - DOS 5+ ROM - SET EXCLUSION REGION LIST
    AX = 6F03h
    DS:DX -> new exclusion region list (see #1115)
Return: CF clear
    AL = 00h
Notes:    DOS saves only the pointer and assumes that the contents of the list
      are never changed, and that regions do not overlap
    if AL > 03h on entry, DOS returns CF set/AL=01h
SeeAlso: AX=6F01h,AX=6F02h
--------D-2170-------------------------------
INT 21 - MS-DOS 7 (Windows95) - GET/SET INTERNATIONALIZATION INFORMATION
    AH = 70h
    AL = subfunction
        00h get ??? info
        CX = buffer size (3Ah bytes needed)
        ES:DI -> buffer
        01h set above info
        CX = number of bytes to set
        DS:SI -> buffer containing ??? info (see #3319)
        02h set general internationalization info
        DS:SI -> buffer containing info (see #3320)
        CX = buffer size in bytes (up to 26h bytes used)
        first three bytes are skipped, the rest is copied to somewhere
          in the DOS data segment
Return: CF clear if successful
        ES:DI buffer filled (func 00h) (see #3319)
        CX = number of bytes actually set or returned
          (max 003Ah for functions 00h and 01h under v7.00, 0026h for
          function 02h)
    CF set on error
        AX = error code
        7000h if function not supported
SeeAlso: AH=38h,AH=65h

Format of MS-DOS v7.0 ??? table:
Offset    Size    Description    (Table 3319)
 00h 58 BYTEs    ??? country-specific information
        returned was (among others) "ENU USA GR"..."AM PM M/d/yy"...
         "dddd,MMMMdd,yyyy" in the German Preview version, and "US"
         instead of "GR" in the US build 450 version (with German
         country setting) and the US build 950a version with US
         country settings
SeeAlso: #3320

Format of MS-DOS v7.0 internationalization table:
Offset    Size    Description    (Table 3320)
 00h  3 BYTEs    unused (and ignored by DOS)
 03h    WORD    country ID (see #0747 at AH=38h)
 05h    WORD    code page (see #1099)
 07h    WORD    date format
 09h  5 BYTEs    ASCIZ current symbol string
 07h  2 BYTEs    ASCIZ thousands separator
 09h  2 BYTEs    ASCIZ decimal separator
 0Bh  2 BYTEs    ASCIZ date separator
 0Dh  2 BYTEs    ASCIZ time separator
 0Fh    BYTE    currency format
        bit 2 = set if currency symbol replaces decimal point
        bit 1 = number of spaces between value and currency symbol
        bit 0 = 0 if currency symbol precedes value
            1 if currency symbol follows value
 10h    BYTE    number of digits after decimal in currency
 11h    BYTE    time format
        bit 0 = 0 if 12-hour clock
            1 if 24-hour clock
 12h    DWORD    address of case map routine
        (FAR CALL, AL = character to map to upper case [>= 80h])
 16h  2 BYTEs    ASCIZ data-list separator
 18h 10 BYTEs    reserved
Note:    this table has the identical format to the extended country information
      retrieved via AH=65h with info ID = 01h
SeeAlso: #0746,#1093
----------217070BX6060-----------------------
INT 21 - PCW Weather Card interface - GET DATA SEGMENT
    AX = 7070h
    BX = 6060h
    CX = 7070h
    DX = 7070h
    SI = 7070h
    DI = 7070h
Return: AX = segment of data structure (see #1116)
Notes:    the data structure is at offset 516 from this segment
    the update byte is at offset 514 from this segment.  Updates are
      once per second while this byte is nonzero and it is decremented
      once per second.  While this byte is 0 updates are once per minute.
SeeAlso: AX=7070h/BX=7070h

Format of PCW Weather Card data structure:
Offset    Type    Description    (Table 1116)
 00h    WORD    hour
 02h    WORD    minute
 04h    WORD    second
 06h    WORD    day
 08h    WORD    month
 0Ah    WORD    year
 0Ch    WORD    ???
 0Eh    WORD    relative barometric pressure (in 1/100 inches)
 10h    WORD    ???
 12h    WORD    ???
 14h    WORD    temperature 1 (in 1/10 degrees F)
 16h    WORD    temperature 1 lowest (in 1/10 degrees F)
 18h    WORD    temperature 1 highest (in 1/10 degrees F)
 1Ah    WORD    temperature 2 (in 1/10 degrees F)
 1Ch    WORD    temperature 2 lowest (in 1/10 degrees F)
 1Eh    WORD    temperature 2 highest (in 1/10 degrees F)
 20h    WORD    wind speed (in MPH)
 22h    WORD    average of 60 wind speed samples (in MPH)
 24h    WORD    highest wind speed (in MPH)
 26h    WORD    wind chill factor  (in 1/10 degrees F)
 28h    WORD    lowest wind chill factor (in 1/10 degrees F)
 2Ah    WORD    ???
 2Ch    WORD    wind direction (in degrees)
 2Eh    WORD    accumulated daily rainfall (in 1/10 inches)
 30h    WORD    accumulated annual rainfall (in 1/10 inches)
----------217070BX7070-----------------------
INT 21 - PCW Weather Card interface - INSTALLATION CHECK
    AX = 7070h
    BX = 7070h
    CX = 7070h
    DX = 7070h
    SI = 7070h
    DI = 7070h
Return: AX = 0070h
    BX = 0070h
    CX = 0070h
    DX = 0070h
    SI = 0070h
    DI = 0070h
SeeAlso: AX=7070h/BX=6060h,AX=8080h
--------D-2171-------------------------------
INT 21 - MS-DOS 7 (Chicago) - LONG FILENAME FUNCTIONS
    AH = 71h
    AL = function
        0Dh reset drive
        39h create directory
        3Ah remove directory
        3Bh set current directory
        41h delete file
        43h get file attributes (BL=00h), set file attributes (BL=01h)
        47h get current directory
        4Eh find first file
        4Fh find next file
        56h move (rename) file
        6Ch create/open file
Return: CF set on error
        AX = error code (see #1020)
        7100h if function not supported
    CF clear if successful
        other registers as for corresponding "old" DOS function
Notes:    if error 7100h is returned, the old-style function should be called
    AX=714Eh returns a "search handle" which must be passed to AX=714Fh;
      when the search is complete, AX=71A1h must be called to terminate
      the search
    for compatibility with DOS versions prior to v7.00, the carry flag
      should be set on call to ensure that it is set on exit
SeeAlso: AH=39h,AH=3Ah,AH=3Bh,AH=41h,AX=4300h,AX=4301h,AX=4304h,AX=4306h
SeeAlso: AX=4307h,AH=47h,AH=4Eh,AH=4Fh,AH=56h,AH=6Ch,AX=714Eh,AX=714Fh
SeeAlso: AX=71A0h,AX=71A1h
--------D-21710D-----------------------------
INT 21 - Windows95 - RESET DRIVE
    AX = 710Dh
    CX = action (see #1117)
    DX = drive number
Return: CF clear
Note:    for compatibility with DOS versions prior to v7.00, the carry flag
      should be set on call to ensure that it is set on exit
SeeAlso: AH=0Dh

(Table 1117)
Values for drive reset action:
 0000h    flush filesystem buffers for drive, and reset drive
 0001h    flush filesystem buffers and cache for drive, and reset drive
 0002h    remount DriveSpace volume
--------D-217139-----------------------------
INT 21 - Windows95 - LONG FILENAME - MAKE DIRECTORY
    AX = 7139h
    DS:DX -> ASCIZ long directory name (including path)
Return: CF clear if successful
    CF set on error
        AX = error code (see #1020)
        7100h if function not supported
Note:    for compatibility with DOS versions prior to v7.00, the carry flag
      should be set on call to ensure that it is set on exit
SeeAlso: AH=39h,AX=713Ah,AX=713Bh
--------D-21713A-----------------------------
INT 21 - Windows95 - LONG FILENAME - REMOVE DIRECTORY
    AX = 713Ah
    DS:DX -> ASCIZ long name of directory to remove
Return: CF clear if successful
    CF set on error
        AX = error code (see #1020)
        7100h if function not supported
Note:    for compatibility with DOS versions prior to v7.00, the carry flag
      should be set on call to ensure that it is set on exit
SeeAlso: AH=3Ah,AX=7139h
--------D-21713B-----------------------------
INT 21 - Windows95 - LONG FILENAME - CHANGE DIRECTORY
    AX = 713Bh
    DS:DX -> ASCIZ long name of directory to make current
Return: CF clear if successful
    CF set on error
        AX = error code (see #1020)
        7100h if function not supported
Note:    for compatibility with DOS versions prior to v7.00, the carry flag
      should be set on call to ensure that it is set on exit
SeeAlso: AH=0Eh,AH=3Bh,AX=7139h
--------D-217141-----------------------------
INT 21 - Windows95 - LONG FILENAME - DELETE FILE
    AX = 7141h
    DS:DX -> ASCIZ long name of file to delete
    SI = wildcard and attributes flag
        0000h wildcards are not allowed, and search attributes are
            ignored
        0001h wildcards are allowed, and only files with matching
            names and attributes are deleted
    CL = search attributes
    CH = must-match attributes
Return: CF clear if successful
    CF set on error
        AX = error code (see #1020)
        7100h if function not supported
Note:    for compatibility with DOS versions prior to v7.00, the carry flag
      should be set on call to ensure that it is set on exit
SeeAlso: AH=41h
--------D-217143-----------------------------
INT 21 - Windows95 - LONG FILENAME - EXTENDED GET/SET FILE ATTRIBUTES
    AX = 7143h
    DS:DX -> ASCIZ filename
    BL = action
        00h retrieve attributes
        Return:    CX = file attributes (see #0765)
        01h set attributes
        CX = attributes
        02h get physical size of compressed file
        Return: DX:AX = actual disk usage of file, in bytes
        03h set last write date/time
        DI = new last-write date (see #1006)
        CX = new last-write time (see #1005)
        04h get last write date/time
        Return:    CX = last write time (see #1005)
            DI = last write date (see #1006)
        05h set last access date
        DI = new last-access date (see #1006)
        06h get last access date
        Return:    DI = last access date (see #1006)
        07h set creation date/time
        DI = new creation date (see #1006)
        CX = new creation time (see #1005)
        SI = hundredths (10-millisecond units past time in CX, 0-199)
        08h get creation date/time
        Return:    CX = creation time (see #1005)
            DI = creation date (see #1006)
            SI = hundredths (10-millisecond units past time in CX)
Return: CF clear if successful
    CF set on error
        AX = error code (see #1020)
        7100h if function not supported
Note:    for compatibility with DOS versions prior to v7.00, the carry flag
      should be set on call to ensure that it is set on exit
SeeAlso: AX=4300h,AX=4301h
--------D-217147-----------------------------
INT 21 - Windows95 - LONG FILENAME - GET CURRENT DIRECTORY
    AX = 7147h
    DL = drive number (00h = current, 01h = A:, etc.)
    DS:SI -> buffer for ASCIZ directory name
Return: CF clear if successful
    CF set on error
        AX = error code (see #1020)
        7100h if function not supported
Notes:    the returned pathname does not include the drive letter, colon, or
      leading backslash
    the provided buffer must be at least as large as the value indicated
      by AX=71A0h
    for compatibility with DOS versions prior to v7.00, the carry flag
      should be set on call to ensure that it is set on exit
SeeAlso: AH=47h,AX=713Bh,AX=71A0h
--------D-21714E-----------------------------
INT 21 - Windows95 - LONG FILENAME - FIND FIRST MATCHING FILE
    AX = 714Eh
    CL = allowable-attributes mask (see #0765 at AX=4301h)
          (bits 0 and 5 ignored)
    CH = required-attributes mask (see #0765)
    SI = date/time format (see #1118)
    DS:DX -> ASCIZ filespec (both "*" and "*.*" match any filename)
    ES:DI -> FindData record (see #1119)
Return: CF clear if successful
        AX = filefind handle (needed to continue search)
        CX = Unicode conversion flags (see #1120)
    CF set on error
        AX = error code
        7100h if function not supported
Notes:    this function is only available when IFSMgr is running, not under bare
      MS-DOS 7
    the application should close the filefind handle with AX=71A1h as soon
      as it has completed its search
    for compatibility with DOS versions prior to v7.00, the carry flag
      should be set on call to ensure that it is set on exit
SeeAlso: AH=4Eh,AX=714Fh,AX=71A1h

(Table 1118)
Values for Windows95 date/time format:
 0000h    use 64-bit file time format
 0001h    use MS-DOS date/time values (see #1005,#1006) in low double-word of
      file time QWORD (date is high word, time is low word of double-word)

Format of Windows95 long filename FindData record:
Offset    Size    Description    (Table 1119)
 00h    DWORD    file attributes
        bits 0-6 standard DOS attributes (see #0765 at INT 21/AX=4301h)
        bit 8: temporary file
 04h    QWORD    file creation time (number of 100ns intervals since 1/1/1601)
 0Ch    QWORD    last access time
 14h    QWORD    last modification time
 1Ch    DWORD    file size (high 32 bits)
 20h    DWORD    file size (low 32 bits)
 24h  8 BYTEs    reserved
 2Ch 260 BYTEs    ASCIZ full filename
130h 14 BYTEs    ASCIZ short filename (for backward compatibility)

Bitfields for Windows95 Unicode conversion flags:
Bit(s)    Description    (Table 1120)
 0    the returned full filename contains underscores for un-convertable
      Unicode characters
 1    the returned short filename contains underscores for un-convertable
      Unicode characters
--------D-21714F-----------------------------
INT 21 - Windows95 - LONG FILENAME - FIND NEXT MATCHING FILE
    AX = 714Fh
    BX = filefind handle (from AX=714Eh)
    SI = date/time format (see #1118)
    ES:DI -> buffer for FindData record (see #1119)
Return: CF clear if successful
        CX = Unicode conversion flags (see #1120)
    CF set on error
        AX = error code
        7100h if function not supported
Notes:    this function is only available when IFSMgr is running, not under bare
      MS-DOS 7
    for compatibility with DOS versions prior to v7.00, the carry flag
      should be set on call to ensure that it is set on exit
SeeAlso: AH=4Eh,AX=714Eh,AX=71A1h
--------D-217156-----------------------------
INT 21 - Windows95 - LONG FILENAME - RENAME FILE
    AX = 7156h
    DS:DX -> ASCIZ old file or directory name (long names allowed)
    ES:DI -> ASCIZ new name (long names allowed)
Return: CF clear if successful
    CF set on error
        AX = error code
        7100h if function not supported
Note:    the file may be renamed into a different directory, but not across
      disks
SeeAlso: AH=56h,AX=7141h
--------D-217160CL00-------------------------
INT 21 - Windows95 - LONG FILENAME - "TRUENAME" - CANONICALIZE PATH
    AX = 7160h
    CL = 00h
    CH = SUBST expansion flag
        00h return a path containing true path for a SUBSTed drive letter
        80h return a path containing the SUBSTed drive letter
    DS:SI -> ASCIZ filename or path (either long name or short name)
    ES:DI -> 261-byte buffer for canonicalized name
Return: CF set on error
        AX = error code
        02h invalid component in directory path or drive letter only
        03h malformed path or invalid drive letter
        ES:DI buffer unchanged
    CF clear if successful
        ES:DI buffer filled with fully qualified name
        AX destroyed
Desc:    determine the canonical name of the specified filename or path,
      corresponding to the undocumented TRUENAME command in COMMAND.COM
Notes:    if a complete path is given, the result will be a short-form complete
      path; otherwise, the given relative path is appended to the
      short-form current directory name, '.'/'..'/'...'/etc. are resolved,
      and the final result uppercased without converting any remaining
      long-form names to short-form
    for compatibility with DOS versions prior to v7.00, the carry flag
      should be set on call to ensure that it is set on exit
SeeAlso: AH=60h,AX=7160h/CL=01h
--------D-217160CL01-------------------------
INT 21 - Windows95 - LONG FILENAME - GET SHORT (8.3) FILENAME FOR FILE
    AX = 7160h
    CL = 01h
    CH = SUBST expansion flag
        00h return a path containing true path for a SUBSTed drive letter
        80h return a path containing the SUBSTed drive letter
    DS:SI -> ASCIZ long filename or path
    ES:DI -> 67-byte buffer for short filename
Return: CF set on error
        AX = error code
        02h invalid component in directory path or drive letter only
        03h malformed path or invalid drive letter
        ES:DI buffer unchanged
    CF clear if successful
        ES:DI buffer filled with equivalent short filename (full path,
          even if relative path given, and all uppercase)
Note:    this call returns the short name for any long-filename portions of
      the provided pathname or filename
SeeAlso: AH=60h,AX=7160h/CL=00h,AX=7160h/CL=02h
--------D-217160CL02-------------------------
INT 21 - Windows95 - LONG FILENAME - GET CANONICAL LONG FILENAME OR PATH
    AX = 7160h
    CL = 02h
    CH = SUBST expansion flag
        00h return a path containing true path for a SUBSTed drive letter
        80h return a path containing the SUBSTed drive letter
    DS:SI -> ASCIZ short filename or path
    ES:DI -> 261-byte buffer for canonicalized long name
Return: CF set on error
        AX = error code
        02h invalid component in directory path or drive letter only
        03h malformed path or invalid drive letter
        ES:DI buffer unchanged
    CF clear if successful
        ES:DI buffer filled with qualified long name (can contain
          lowercase letters)
Desc:    determine the canonical name of the specified filename or path,
      corresponding to the undocumented TRUENAME command in COMMAND.COM
Note:    this call returns the short name for any long-filename portions of
      the provided pathname or filename
BUG:    even though the maximum length of a complete long pathname is 260
      characters, Windows95 returns CF set/AX=0003h even if the file
      exists whenever the full pathname is more than 255 characters
SeeAlso: AH=60h,AX=7160h/CL=00h,AX=7160h/CL=01h
--------D-21716C-----------------------------
INT 21 - Windows95 - LONG FILENAME - CREATE OR OPEN FILE
    AX = 716Ch
    BX = access mode and sharing flags (see #1122,also AX=6C00h)
    CX = attributes
    DX = action (see #1121)
    DS:SI -> ASCIZ filename
    DI = alias hint (number to append to short filename for disambiguation)
Return: CF clear if successful
        AX = file handle
        CX = action taken
        0001h file opened
        0002h file created
        0003h file replaced
    CF set on error
        AX = error code (see #1020)
        7100h if function not supported
SeeAlso: AX=6C00h,AX=7141h,AX=7156h,AX=71A9h

Bitfields for Windows95 long-name open action:
Bit(s)    Description    (Table 1121)
 0    open file (fail if file does not exist)
 1    truncate file if it already exists (fail if file does not exist)
 4    create new file if file does not already exist (fail if exists)
Note:    the only valid combinations of multiple flags are bits 4&0 and 4&1

Bitfields for Windows95 file access/sharing modes:
Bit(s)    Description    (Table 1122)
 2-0    file access mode
    000 read-only
    001 write-only
    010 read-write
    100 read-only, do not modify file's last-access time
 6-4    file sharing modes
 7    no-inherit flag
 8    do not buffer data (requires that all reads/writes be exact physical
      sectors)
 9    do not compress file even if volume normally compresses files
 10    use alias hint in DI as numeric tail for short-name alias
 12-11    unused??? (0)
 13    return error code instead of generating INT 24h if critical error
      while opening file
 14    commit file after every write operation
SeeAlso: #0749
--------D-2171A0-----------------------------
INT 21 - Windows95 - LONG FILENAME - GET VOLUME INFORMATION
    AX = 71A0h
    DS:DX -> ASCIZ root name (e.g. "C:\")
    ES:DI -> buffer for file system name
    CX = size of ES:DI buffer
Return: CF clear if successful
        BX = file system flags (see #1123)
        CX = maximum length of file name [usually 255]
        DX = maximum length of path [usually 260]
        ES:DI buffer filled (ASCIZ, e.g. "FAT","NTFS","CDFS")
    CF set on error
        AX = error code
        7100h if function not supported
Notes:    for the file system name buffer, 32 bytes should be sufficient; that's
     what is used in some sample code by Walter Oney from Microsoft.
    this function accesses the disk the first time it is called
SeeAlso: AX=714Eh,AX=7160h/CL=00h

Bitfields for long filename volume information flags:
Bit(s)    Description    (Table 1123)
 0    searches are case sensitive
 1    preserves case in directory entries
 2    uses Unicode characters in file and directory names
 3-13    reserved (0)
 14    supports DOS long filename functions
 15    volume is compressed
--------D-2171A1-----------------------------
INT 21 - Windows95 - LONG FILENAME - "FindClose" - TERMINATE DIRECTORY SEARCH
    AX = 71A1h
    BX = filefind handle (from AX=714Eh)
Return: CF clear if successful
    CF set on error
       AX = error code
        7100h if function not supported
Notes:    this function must be called after starting a search with AX=714Eh,
      to indicate that the search handle returned by that function will
      no longer be used
    this function is only available when IFSMgr is running, not under bare
      MS-DOS 7
SeeAlso: AH=4Eh,AX=714Eh,AX=714Fh
--------D-2171A2-----------------------------
INT 21 U - Windows95 - internal
    AX = 71A2h
    ???
Return: ???
Note:    documented as "for internal use by Windows 95 only"
--------D-2171A3-----------------------------
INT 21 U - Windows95 - internal
    AX = 71A3h
    ???
Return: ???
Note:    documented as "for internal use by Windows 95 only"
--------D-2171A4-----------------------------
INT 21 U - Windows95 - internal
    AX = 71A4h
    ???
Return: ???
Note:    documented as "for internal use by Windows 95 only"
--------D-2171A5-----------------------------
INT 21 U - Windows95 - internal
    AX = 71A5h
    ???
Return: ???
Note:    documented as "for internal use by Windows 95 only"
--------D-2171A6-----------------------------
INT 21 - Windows95 - LONG FILENAME - GET FILE INFO BY HANDLE
    AX = 71A6h
    BX = file handle
    DS:DX -> buffer for file information (see #1124)
    CF set
Return: CF clear if successful
        file information record filled
    CF set on error
        AX = error code
        7100h if function not supported
SeeAlso: AX=71A7h/BL=00h

Format of Windows95 file information:
Offset    Size    Description    (Table 1124)
 00h    DWORD    file attributes
 04h    QWORD    creation time (0 = unsupported)
 0Ch    QWORD    last access time (0 = unsupported)
 14h    QWORD    last write time
 1Ch    DWORD    volume serial number
 20h    DWORD    high 32 bits of file size
 24h    DWORD    low 32 bits of file size
 28h    DWORD    number of links to file
 2Ch    DWORD    unique file identifier (high 32 bits)
 30h    DWORD    unique file identifier (low 32 bits)
Note:    the file identifer and volume serial number together uniquely identify
      a file while it is open; the identifier may change when the system
      is restarted or the file is first opened
--------D-2171A7BL00-------------------------
INT 21 - Windows95 - LONG FILENAME - FILE TIME TO DOS TIME
    AX = 71A7h
    BL = 00h
    DS:SI -> QWORD file time
Return: CF clear if successful
        CX = DOS time (see #1005)
        DX = DOS date (see #1006)
        BH = hundredths (10-millisecond units past time in CX)
    CF set on error
        AX = error code
        7100h if function not supported
Desc:    convert Win95 64-bit file time (UTC) into DOS-style date and time
      (local timezone)
Note:    the conversion fails if the file time's value is outside the range
      1/1/1980 and 12/31/2107
SeeAlso: AX=71A6h,AX=71A7h/BL=01h
--------D-2171A7BL01-------------------------
INT 21 - Windows95 - LONG FILENAME - DOS TIME TO FILE TIME
    AX = 71A7h
    BL = 01h
    CX = DOS time (see #1005)
    DX = DOS date (see #1006)
    BH = hundredths (10-millisecond units past time in CX)
    ES:DI -> buffer for QWORD file time
Return: CF clear if successful
        ES:DI buffer filled
    CF set on error
        AX = error code
        7100h if function not supported
Desc:    convert DOS-style date and time (local timezone) into Win95 64-bit
      file time (UTC)
SeeAlso: AX=71A6h,AX=71A7h/BL=00h
--------D-2171A8-----------------------------
INT 21 - Windows95 - LONG FILENAME - GENERATE SHORT FILENAME
    AX = 71A8h
    DS:SI -> ASCIZ long filename (no path allowed!)
    ES:DI -> buffer for ASCIZ short filename
    DH = short name's format
        00h 11-char directory entry/FCB filename format
        01h DOS 8.3
    DL = character sets
        bits 7-4: short name's character set (see #1125)
        bits 3-0: long name's character set (see #1125)
Return: CF clear if successful
        ES:DI buffer filled
    CF set on error
        AX = error code
        7100h if function not supported
Note:    this function uses the same algorithm as the filesystem except that
      the returned name never has a numeric tail for disambiguation
SeeAlso: AX=7160h/CL=00h,AX=7160h/CL=02h,AX=71A7h/BL=00h

(Table 1125)
Values for Windows95 filename character set:
 00h    Windows ANSI
 01h    current OEM character set
 02h    Unicode
--------D-2171A9-----------------------------
INT 21 - Windows95 - LONG FILENAME - SERVER CREATE OR OPEN FILE
    AX = 71A9h
    BX = access mode and sharing flags (see #1122,also AX=6C00h)
    CX = attributes
    DX = action (see #1121)
    DS:SI -> ASCIZ filename
    DI = alias hint (number to append to short filename for disambiguation)
Return: CF clear if successful
        AX = global file handle
        CX = action taken
        0001h file opened
        0002h file created
        0003h file replaced
    CF set on error
        AX = error code (see #1020)
        7100h if function not supported
Note:    for use by real-mode servers only
SeeAlso: AX=6C00h,AX=716Ch
--------D-2171AABH00-------------------------
INT 21 - Windows95 - LONG FILENAME - CREATE SUBST
    AX = 71AAh
    BH = 00h
    BL = drive number (00h = default, 01h = A:, etc.)
    DS:DX -> ASCIZ pathname to associate with drive letter
Return: CF clear if successful
    CF set on error
        AX = error code (see #1020)
        7100h if function not supported
SeeAlso: AX=71AAh/BH=01h,AX=71AAh/BH=02h,INT 2F/AX=1000h,#0984
--------D-2171AABH01-------------------------
INT 21 - Windows95 - LONG FILENAME - TERMINATE SUBST
    AX = 71AAh
    BH = 01h
    BL = drive number (01h = A:, etc.)
Return: CF clear if successful
    CF set on error
        AX = error code (see #1020)
        7100h if function not supported
Note:    the specified drive number may not be 00h (default), and presumably not
      the current drive either
SeeAlso: AX=71AAh/BH=00h,AX=71AAh/BH=02h,INT 2F/AX=1000h,#0984
--------D-2171AABH02-------------------------
INT 21 - Windows95 - LONG FILENAME - QUERY SUBST
    AX = 71AAh
    BH = 02h
    BL = drive number (01h = A:, etc.)
    DS:DX -> buffer for ASCIZ pathname associated with drive letter
Return: CF clear if successful
        DS:DX buffer filled
    CF set on error
        AX = error code (see #1020)
        7100h if function not supported
Note:    the specified drive number may not be 00h (default drive)
SeeAlso: AX=71AAh/BH=00h,AX=71AAh/BH=01h,INT 2F/AX=1000h,#0984
--------D-2172-------------------------------
INT 21 - "Chicago" - LFN-FindClose
    AH = 72h
    details not available
Return:    CF clear if successful
    CF set on error
        AX = error code (see #1020)
        7200h if function not supported (e.g. under bare MS-DOS 7)
Note:    this function was present in beta versions of Windows95, but is
      probably not present in the release version
SeeAlso: AX=71A1h
--------D-2173-------------------------------
INT 21 - MS-DOS 7 - DRIVE LOCKING ???
    AH = 73h
    DL = drive (0=current, 1=A:, etc.)
    CL = which flag to get or set
        00h drive flag???
        01h ???
    AL = subfunction
        00h get ???
        01h set ???
        CH = new values for ??? flags
            bit 1: ??? (CL=00h only)
            bit 3: ??? (CL=01h only)
Return: CF clear if successful
        for AL=00h:
        AL = value of CL on entry
        for CL=00h: AH = new flag and 06h (i.e. bits 1 and 2 used)
        for CL=01h: AH = new flag and 08h (i.e. bit 3 used)
        (flag being taken from a table of bytes)
    CF set on error
        AX = error code (01h,0Fh,etc.) (see #1020)
        7300h if function not supported
Note:    these two subfunctions are available even when only the MS-DOS kernel
      is running
--------D-217302-----------------------------
INT 21 - MS-DOS 7 (Windows95) - FAT32 - "Get_ExtDPB" - GET EXTENDED DPB
    AX = 7302h
    DL = drive number (00h=default, 01h=A:, etc.)
    ES:DI -> buffer for drive parameter block (DPB) (see #3295)
    CX = length of buffer
Return: CF clear if successful
        ES:DI buffer filled
    CF set on error
        AX = error code
SeeAlso: AX=7303h,AX=7304h,AH=1Fh,AH=32h

Format of Extended Drive Parameter Block:
Offset    Size    Description    (Table 3295)
 00h 24 BYTEs    standard DOS 4+ DPB
 18h    BYTE    "dpb_flags" (undocumented)
 19h    DWORD    pointer to next DPB
 1Dh    WORD    cluster at which to start search for free space when writing,
        usually the last cluster allocated
 1Fh    WORD    number of free clusters on drive, FFFFh = unknown
 21h    WORD    high word of free cluster count
 23h    WORD    active FAT/mirroring
        bits 3-0: the 0-based FAT number of the active FAT
        bits 6-4: reserved (0)
        bit 7: do not mirror active FAT to inactive FATs
 25h    WORD    sector number of file system information sector, or
          FFFFh for none (see also #3296)
 27h    WORD    sector number of backup boot sector
 29h    DWORD    first sector number of the first cluster
 2Dh    DWORD    maximum cluster number
 31h    DWORD    number of sectors occupied by FAT
 35h    DWORD    cluster number of start of root directory
Note:    except for offset 18h, all of the first 33 bytes are identical to
      the standard DOS 4-6 DPB
SeeAlso: #0742 at AH=32h,#3300

Format of File System Information structure:
Offset    Size    Description    (Table 3296)
 00h    DWORD    signature 61417272h
 04h    DWORD    number of free clusters (FFFFFFFFh if unknown)
 08h    DWORD    most recently allocated cluster
 0Ch 12 BYTEs    reserved
SeeAlso: #3295
--------D-217303-----------------------------
INT 21 - MS-DOS 7 (Windows95) - FAT32 - GET EXTENDED FREE SPACE ON DRIVE
    AX = 7303h
    DS:DX -> ASCIZ string for drive ("C:\" or "\\SERVER\Share")
    ES:DI -> buffer for extended free space structure (see #3297)
    CX = length of buffer for extended free space
Return: CF clear if successful
        ES:DI buffer filled
    CF set on error
        AX = error code
SeeAlso: AX=7302h,AX=7304h,AX=7305h,AH=36h

Format of extended free space structure:
Offset    Size    Description    (Table 3297)
 00h    WORD    ??? "The true size of the drive. Get_ExtFreeSpace returns
          the value to this field."
 02h    WORD    (call) structure version??? (0000h)
        (ret) ???
 04h    DWORD    number of sectors per cluster (with adjustment for compression)
 08h    DWORD    number of bytes per sector
 1Ch    DWORD    number of available clusters
 20h    DWORD    total number of clusters on the drive
 24h    DWORD    number of physical sectors available on the drive, without
          adjustment for compression
 28h    DWORD    total number of physical sectors on the drive, without
          adjustment for compression
 2Ch    DWORD    number of available allocation units, without adjustment
          for compression
 30h    DWORD    total allocation units, without adjustment for compression
 34h  8 BYTEs    reserved
--------D-217304-----------------------------
INT 21 - MS-DOS 7 (Windows95) - FAT32 - Set DPB TO USE FOR FORMATTING
    AX = 7304h
    DL = drive number (00h=default, 01h=A:, etc.)
    ES:DI -> buffer for Set_DPBforFormat structure (see #3298)
Return: CF clear if successful
        ES:DI buffer updated
    CF set on error
        AX = error code
SeeAlso: AX=7302h,AX=7303h,AX=7305h

Format of Set_DPBforFormat structure:
Offset    Size    Description    (Table 3298)
 00h    WORD    (call) size
 02h    WORD    (call) structure version???  (0000h)
        (ret) ???
 04h    DWORD    (call) function number
        00h invalidate DPB counts
        01h rebuild DPB from BPB
        02h force media change (next access to drive rebuild DPB)
        03h get/set active FAT number and mirroring
        04h get/set root directory cluster number
---function 00h---
 08h    DWORD    new DPB free count (00000000h=no change, FFFFFFFFh=unknown)
 0Ch    DWORD    new DPB next-free (00000000h=no change, FFFFFFFFh=unknown)
 10h    DWORD    unused
 14h    DWORD    unused
---function 01h---
 08h    DWORD    unused???
 0Ch    DWORD    (call) -> BIOS Parameter Block from which to rebuild DPB
 10h    DWORD    unused
 14h    DWORD    unused
---function 02h---
 08h    DWORD    unused
 0Ch    DWORD    unused
 10h    DWORD    unused
 14h    DWORD    unused
---function 03h---
 08h    DWORD    (call) new active FAT/mirroring state, or FFFFFFFFh to get
        bits 3-0: the 0-based FAT number of the active FAT
        bits 6-4: reserved (0)
        bit 7: do not mirror active FAT to inactive FATs
 0Ch    DWORD    (ret) previous active FAT/mirroring state (as above)
 10h    DWORD    unused
 14h    DWORD    unused
---function 04h---
 08h    DWORD    (call) new root directory cluster number
            FFFFFFFFh to get current
 0Ch    DWORD    (ret) previous root directory cluster number
 10h    DWORD    unused
 14h    DWORD    unused
--------D-217305-----------------------------
INT 21 - MS-DOS 7 (Windows95) - FAT32 - EXTENDED ABSOLUTE DISK READ/WRITE
    AX = 7305h
    DL = drive number (00h=default, 01h=A:, etc.)
    SI = read/write mode flags (see #3299)
    DS:BX -> disk I/O packet (see #1884 at INT 25)
Return: CF clear if successful
    CF set on error
        AX = error code
SeeAlso: AX=7302h,AX=7304h,INT 25,INT 26

Bitfields for Extended Absolute Disk Read/Write mode flags:
Bit(s)    Description    (Table 3299)
 0    direction (0=read, 1=write)
 12-1    reserved (0)
 14-13    write type (should be 00 on reads)
    00 unknown data
    01 FAT data
    10 directory data
    11 file data
 15    reserved (0)
--------v-217575-----------------------------
INT 21 - VIRUS - "LEGO" -INSTALLATION CHECK
    AX = 7575h
Return: AX = 4321h if resident
SeeAlso: AX=6969h,AH=76h"VIRUS"
--------v-2176-------------------------------
INT 21 - VIRUS - "Klaeren"/"Hate" - INSTALLATION CHECK
    AH = 76h
Return: AL = 48h if resident
SeeAlso: AX=7575h,AX=7700h"VIRUS"
--------v-217700-----------------------------
INT 21 - VIRUS - "Growing Block" - INSTALLATION CHECK
    AX = 7700h
Return: AX = 0920h if resident
SeeAlso: AH=76h,AX=7BCEh,AH=7Fh
--------V-217734-----------------------------
INT 21 U - SCROLLit v1.7 - INSTALLATION CHECK
    AX = 7734h
Return: DX = 3477h if installed
        AX = segment of resident code
Program: ScrollIt is a shareware backscroll utility by Bromfield Software
      Products
--------U-217761-----------------------------
INT 21 - WATCH.COM v3.2+ - INSTALLATION CHECK
    AX = 7761h ('wa')
Return: AX = 6177h
Note:    WATCH.COM is part of the "TSR" package by TurboPower Software
SeeAlso: INT 16/AX=7761h
--------v-217BCE-----------------------------
INT 21 - VIRUS - "Whisper"/"Taipan" - INSTALLATION CHECK
    AX = 7BCEh
Return: AX = 7BCEh if resident (???)
SeeAlso: AX=5454h"VIRUS",AX=7700h,AX=7BCFh,AH=7Fh"VIRUS"
--------v-217BCF-----------------------------
INT 21 - VIRUS - "Tai-Pan.666"/"Doom II Death" - INSTALLATION CHECK
    AX = 7BCFh
Return: AX = 7BCFh if resident
SeeAlso: AX=7BCEh"VIRUS",AH=7Dh"VIRUS"
--------v-217D-------------------------------
INT 21 - VIRUS - "OffSpring" - INSTALLATION CHECK
    AH = 7Dh
Return: AH = FAh if installed
SeeAlso: AX=7BCFh"VIRUS",AH=7Fh"VIRUS"
--------v-217F-------------------------------
INT 21 - VIRUS - "Squeaker","ASeXual" - INSTALLATION CHECK
    AH = 7Fh
Return: AH = 80h if resident
SeeAlso: AX=7BCEh,AH=83h"VIRUS"
--------D-2180-------------------------------
INT 21 - European MS-DOS 4.0 - "AEXEC" - EXECUTE PROGRAM IN BACKGROUND
    AH = 80h
    CX = mode
        0000h place child in zombie mode on exit to preserve exit code
        0001h discard child process and exit code on termination
    DS:DX -> ASCIZ full program name
    ES:BX -> parameter block (as for AX=4B00h)
Return: CF clear if successful
        AX = Command Subgroup ID (CSID)
    CF set on error
        AX = error code (see #1020 at AH=59h/BX=0000h)
Program: European MS-DOS 4.0 was written for Siemens in Germany and then used
      by several other European OEMs; its release falls between mainstream
      versions 3.2 and 3.3
Desc:    asynchronously execute a program, creating a new process for it
Notes:    this function is called by the DETACH command
    there is a system-wide limit of 32 processes
    the CSID is used to identify all processes that have been spawned by
      a given process, whether directly or indirectly
    programs to be run in the background must use the new executable format
      (see #0937 at AH=4Bh)
    background processes may only perform asynchronous (background) EXECs,
      either this function or AX=4B04h
    background processes may execute INT 11, INT 12, INT 21, INT 2A, and
      INT 2F at any time; they may execute INT 10 and INT 16 only while
      they have opened a popup screen via INT 2F/AX=1401h; no other
      interrupts may be executed from the background
    background processes may not use drive B: or overlay their code
      segments
    see AX=8700h for an installation check
    the "NE" new executable format made its first appearance in European
      MS-DOS 4.0
SeeAlso: AH=4Bh,AH=87h,INT 2F/AX=1400h"POPUP"
----------218080-----------------------------
INT 21 - PCW Weather Card interface - UNINSTALL PCW.COM AND FREE MEMORY
    AX = 8080h
Return: ???
SeeAlso: AX=7070h/BX=7070h
--------D-2181-------------------------------
INT 21 - European MS-DOS 4.0 - "FREEZE" - STOP A PROCESS
    AH = 81h
    BX = flag (00h freeze command subtree, 01h only specified process)
    CX = Process ID of head of command subtree
Return: CF clear if successful
    CF set on error
        AX = error code (no such process)
Desc:    temporarily suspend a process or a process and all of its children
Note:    if BX=0001h, this call will not return until the process is actually
      frozen, which may not be until after it unblocks from an I/O
      operation
SeeAlso: AH=82h,AH=89h,AX=8E00h,INT 15/AX=101Dh
--------D-2182-------------------------------
INT 21 - European MS-DOS 4.0 - "RESUME" - RESTART A PROCESS
    AH = 82h
    BX = flag (00h resume command subtree, 01h only specified process)
    CX = Process ID of head of command subtree
Return: CF clear if successful
    CF set on error
        AX = error code (no such process)
Desc:    restart a previously-suspended process or a process and all of its
      children
SeeAlso: AH=81h,INT 15/AX=101Eh
--------D-2183-------------------------------
INT 21 - European MS-DOS 4.0 - "PARTITION" - GET/SET FOREGROUND PARTITION SIZE
    AH = 83h
    AL = function
        00h get size
        01h set new size
        BX = new size in paragraphs
Return: CF clear if successful
        BX = current size (function 00h) or old size (function 01h)
    CF set on error
        AX = error code (01h,07h,0Dh)(see #1020 at AH=59h/BX=0000h)
Desc:    specify or determine how much memory may be allocated by the foreground
      process
Note:    if the partition size is set to 0000h, no partition management is done
      and all memory allocation is compatible with DOS 3.2.
    the partition size can be changed regardless of what use is being made
      of the changed memory; subsequent allocations will follow the
      partition rules (foreground processes may allocate only foreground
      memory; background processes allocate background memory first, then
      foreground memory)
SeeAlso: AH=48h,AH=4Ah
--------v-2183-------------------------------
INT 21 - VIRUS - "SVC" - INSTALLATION CHECK
    AH = 83h
Return: DX = 1990h if resident
SeeAlso: AH=76h,AH=84h"VIRUS"
--------v-2184-------------------------------
INT 21 - VIRUS - "SVC 5.0" or "SVC 6.0" - INSTALLATION CHECK
    AH = 84h
Return: DX = 1990h if resident
        BH = version number (major in high nybble, minor in low)
SeeAlso: AH=83h"VIRUS",AH=89h"VIRUS"
--------D-218400-----------------------------
INT 21 - European MS-DOS 4.0 - "CREATMEM" - CREATE A SHARED MEMORY AREA
    AX = 8400h
    BX = size in bytes (0000h = 65536)
    CX = flags
        bit 6: zero-initialize segment
    DS:DX -> ASCIZ name (must begin with "\SHAREMEM\")
Return: CF clear if successful
        AX = segment address of shared memory global object
    CF set on error
        AX = error code (06h,08h) (see #1020 at AH=59h/BX=0000h)
Desc:    create an area of memory which may be accessed by multiple processes
Notes:    shared memory objects are created as special files (thus the
      restriction on the name)
    on successful creation, the reference count is set to 1
SeeAlso: AX=8401h,AX=8402h,INT 15/AX=DE19h
--------D-218401-----------------------------
INT 21 - European MS-DOS 4.0 - "GETMEM" - OBTAIN ACCESS TO SHARED MEMORY AREA
    AX = 8401h
    CX = flags
        bit 7: writable segment (ignored by MS-DOS 4.0)
    DS:DX -> ASCIZ name (must begin with "\SHAREMEM\")
Return: CF clear if successful
        AX = segment address of shared memory global object
        CX = size in bytes
    CF set on error
        AX = error code (invalid name)
Desc:    get address of a previously-created area of memory which may be
      accessed by multiple processes
Note:    this call increments the reference count for the shared memory area
SeeAlso: AX=8400h,AX=8402h
--------D-218402-----------------------------
INT 21 - European MS-DOS 4.0 - "RELEASEMEM" - FREE SHARED MEMORY AREA
    AX = 8402h
    BX = handle (segment address of shared memory object)
Return: CF clear if successful
    CF set on error
        AX = error code (no such name)
Desc:    indicate that the specified area of shared memory will no longer be
      used by the caller
Note:    the reference count is decremented and the shared memory area is
      deallocated if the new reference count is zero
SeeAlso: AX=8400h,AX=8401h,INT 15/AX=DE19h
--------D-2185-------------------------------
INT 21 U - European MS-DOS 4.0 - ???
    AH = 85h
    ???
Return: ???
--------D-2186-------------------------------
INT 21 - European MS-DOS 4.0 - "SETFILETABLE" - INSTALL NEW FILE HANDLE TABLE
    AH = 86h
    BX = total number of file handles in new table
Return: CF clear if successful
    CF set on error
        AX = error code (06h,08h) (see #1020 at AH=59h/BX=0000h)
Desc:    adjust the size of the per-process open file table, thus raising or
      lowering the limit on the number of files the caller can open
      simultaneously
Notes:    any currently-open files are copied to the new table
    if the table is increased beyond the default 20 handles, only the
      first 20 will be inherited by child processes
    error 06h is returned if the requested number of handles exceeds
      system limits or would require closing currently-open files
SeeAlso: AH=26h,AH=67h
--------D-2187-------------------------------
INT 21 - European MS-DOS 4.0 - "GETPID" - GET PROCESS IDENTIFIER
    AH = 87h
Return: AX = PID
    BX = parent process's PID
    CX = Command Subgroup ID (CSID)
Program: European MS-DOS 4.0 was written for Siemens in Germany and then used
      by several other European OEMs; its release falls between mainstream
      versions 3.2 and 3.3
Desc:    determine an identifier by which to access the calling process
Notes:    called by MS C v5.1 getpid() function
    this function apparently must return AX=0001h for INT 21/AH=80h to
      succeed
    one possible check for European MS-DOS 4.0 is to issue this call with
      AL=00h and check whether AL is nonzero on return
SeeAlso: AH=30h,AH=62h,AH=80h
Index:    installation check;European MS-DOS 4.0
--------D-2188-------------------------------
INT 21 U - European MS-DOS 4.0 - ???
    AH = 88h
    ???
Return: ???
SeeAlso: AH=87h
--------D-2189-------------------------------
INT 21 - European MS-DOS 4.0 - SLEEP
    AH = 89h
    CX = time in milliseconds or 0000h to give up time slice
Return: CF clear if successful
        CX = 0000h
    CF set on error
        AX = error code (interrupted system call)
        CX = sleep time remaining
Desc:    suspend the calling process for the specified duration
Notes:    the sleep interval is rounded up to the next higher increment of the
      scheduler clock, and may be extended further if other processes are
      running
    this call may be interrupted by signals (see AH=8Dh)
    reportedly called by Microsoft C 4.0 startup code
    background processes have higher priority than the foreground process,
      and should thus periodically yield the CPU
SeeAlso: AH=81h,INT 15/AX=1000h,INT 2F/AX=1680h,INT 7A/BX=000Ah
--------v-2189-------------------------------
INT 21 - VIRUS - "Vriest" - INSTALLATION CHECK
    AH = 89h
Return: AX = 0123h if resident
SeeAlso: AH=84h"VIRUS",AH=90h"VIRUS"
--------D-218A-------------------------------
INT 21 - European MS-DOS 4.0 - "CWAIT" - WAIT FOR CHILD TO TERMINATE
    AH = 8Ah
    BL = range (00h command subtree, 01h any child)
    BH = suspend flag
        00h suspend if children exist but none are dead
        01h return if no dead children
    CX = Process ID of head of command subtree
Return: CF clear if successful
        AH = termination type (see #1126)
        AL = return code from child or aborting signal
        BX = PID of child (0000h if no dead children)
    CF set on error
        AX = error code (no child,interrupted system call)
Desc:    get return code from an asynchronously-executed child program,
      optionally waiting if no return code is available
SeeAlso: AH=4Bh,AH=4Dh,AH=80h,AH=8Dh

(Table 1126)
Values for termination type:
 00h    normal termination
 01h    aborted by Control-C
 02h    aborted by I/O error
 03h    terminate and stay resident
 04h    aborted by signal
 05h    aborted by program error
--------D-218B-------------------------------
INT 21 U - European MS-DOS 4.0 - ???
    AH = 8Bh
    ???
Return: ???
SeeAlso: AH=87h
--------D-218C-------------------------------
INT 21 - European MS-DOS 4.0 - SET SIGNAL HANDLER
    AH = 8Ch
    AL = signal number (see #1127)
    BL = action (see #1128)
    DS:DX -> signal handler (see #1129)
Return: CF clear if successful
        AL = previous action
        ES:BX -> previous signal handler
    CF set on error
        AX = error code (01h,invalid SigNumber or Action)
          (see #1020 at AH=59h/BX=0000h)
Desc:    set the routine which will be invoked on a number of exceptional
      conditions
Note:    all signals will be sent to the most recently installed handler
SeeAlso: AH=8Dh

(Table 1127)
Values for European MS-DOS 4.0 signal number:
 01h    SIGINTR        Control-C or user defined interrupt key
 08h    SIGTERM        program termination
 09h    SIGPIPE        broken pipe
 0Dh    SIGUSER1    reserved for user definition
 0Eh    SIGUSER2    reserved for user definition

(Table 1128)
Values for signal action:
 00h    SIG_DFL        terminate process on receipt
 01h    SIG_IGN        ignore signal
 02h    SIG_GET        signal is accepted
 03h    SIG_ERR        sender gets error
 04h    SIG_ACK        acknowledge received signal and clear it, but don't
              change current setting

(Table 1129)
Values signal handler is called with:
    AL = signal number (see #1127)
    AH = signal argument
Return: RETF, CF set: terminate process
    RETF, CF clear, ZF set: abort any interrupted system call with an error
    RETF, CF clear, ZF clear: restart any interrupted system call
    IRET: restart any interrupted system call
Note:    the signal handler may also perform a nonlocal GOTO by resetting the
      stack pointer and jumping; before doing so, it should dismiss the
      signal by calling this function with BL=04h
--------D-218D-------------------------------
INT 21 - European MS-DOS 4.0 - SEND SIGNAL
    AH = 8Dh
    AL = signal number (see #1127)
    BH = signal argument
    BL = action
        00h send to entire command subtree
        01h send only to specified process
    DX = Process ID
Return: CF clear if successful
    CF set on error
        AX = error code (01h,06h)(see #1020 at AH=59h/BX=0000h)
Desc:    invoke the exceptional-condition handler for the specified process
Note:    error 06h may be returned if one or more of the affected processes
      have an error handler for the signal
SeeAlso: AH=8Ch
--------D-218E00BH00-------------------------
INT 21 - European MS-DOS 4.0 - "SETPRI" - GET/SET PROCESS PRIORITY
    AX = 8E00h
    BH = 00h
    BL = action
        00h set priority for command subtree
        01h set priority for specified process only
    CX = Process ID
    DH = 00h
    DL = change in priority (00h to get priority)
Return: CF clear if successful
        DL = process priority
        DH destroyed
    CF set on error
        AX = error code (01h,no such process)(see #1020 at AH=59h)
Desc:    specify or determine the execution priority of the specified process
      or the process and all of its children
SeeAlso: AH=81h
--------D-218F-------------------------------
INT 21 U - European MS-DOS 4.0 - ???
    AH = 8Fh
    ???
Return: ???
SeeAlso: AH=87h
--------D-2190-------------------------------
INT 21 U - European MS-DOS 4.0 - ???
    AH = 90h
    ???
Return: ???
SeeAlso: AH=87h
--------v-2190-------------------------------
INT 21 - VIRUS - "Carioca" - INSTALLATION CHECK
    AH = 90h
Return: AH = 01h if resident
SeeAlso: AH=89h"VIRUS",AX=9753h"VIRUS"
--------D-2191-------------------------------
INT 21 U - European MS-DOS 4.0 - ???
    AH = 91h
    ???
Return: ???
SeeAlso: AH=87h
--------D-2192-------------------------------
INT 21 U - European MS-DOS 4.0 - ???
    AH = 92h
    ???
Return: ???
SeeAlso: AH=87h
--------D-2193-------------------------------
INT 21 - European MS-DOS 4.0 - "PIPE" - CREATE A NEW PIPE
    AH = 93h
    CX = size in bytes
Return: CF clear if successful
        AX = read handle
        BX = write handle
    CF set on error
        AX = error code (08h) (see #1020 at AH=59h/BX=0000h)
Desc:    create a communications channel which may be used for interprocess
      data and command exchanges
SeeAlso: AH=3Ch,AH=3Fh"DOS",AH=40h"DOS",AH=84h
--------D-2194-------------------------------
INT 21 U - European MS-DOS 4.0 - ???
    AH = 94h
    ???
Return: ???
SeeAlso: AH=87h
--------D-2195-------------------------------
INT 21 - European MS-DOS 4.0 - HARD ERROR PROCESSING
    AH = 95h
    AL = new state
       00h enabled
       01h disabled, automatically fail hard errors
Return: AX = previous setting
Desc:    specify whether hard (critical) errors should automatically fail the
      system call or invoke an INT 24
SeeAlso: INT 24
--------D-2196-------------------------------
INT 21 U - European MS-DOS 4.0 - ???
    AH = 96h
    ???
Return: ???
--------D-2197-------------------------------
INT 21 U - European MS-DOS 4.0 - ???
    AH = 97h
    ???
Return: ???
--------v-219753-----------------------------
INT 21 - VIRUS - "Nina" - INSTALLATION CHECK
    AX = 9753h
Return: never (executes original program) if virus resident
SeeAlso: AH=90h"VIRUS",AX=A1D5h"VIRUS",AX=9AD5h"VIRUS"
--------D-2198-------------------------------
INT 21 U - European MS-DOS 4.0 - ???
    AH = 98h
    ???
Return: ???
--------D-2199-------------------------------
INT 21 u - European MS-DOS 4.0 - "PBLOCK" - BLOCK A PROCESS
    AH = 99h
    DS:BX -> memory location to block on
    CX = timeout in milliseconds
    DH = nonzero if interruptable
Return: CF clear if awakened by event
        AX = 0000h
    CF set if unusual wakeup
        ZF set if timeout, clear if interrupted by signal
        AX = nonzero
Desc:    suspend calling process until another process sends a "restart" signal
      or a timeout occurs
SeeAlso: AH=9Ah,INT 2F/AX=0802h
--------D-219A-------------------------------
INT 21 u - European MS-DOS 4.0 - "PRUN" - UNBLOCK A PROCESS
    AH = 9Ah
    DS:BX -> memory location processes may have blocked on
Return: AX = number of processes awakened
    ZF set if no processes awakened
Program: European MS-DOS 4.0 was written for Siemens in Germany and then used
      by several other European OEMs; its release falls between mainstream
      versions 3.2 and 3.3
Desc:    restart all processes waiting for the specified "restart" signal
SeeAlso: AH=99h,INT 2F/AX=0802h
--------v-219AD5------------------------
INT 21 - VIRUS - "Massacre/Beavis" - INSTALLATION CHECK
    AX = 9AD5h
Return: AX = 9AD4h if resident
SeeAlso: AX=6969h"VIRUS",AX=A1D5h"VIRUS"
--------I-21A0-------------------------------
INT 21 - Attachmate Extra! - GET 3270 DISPLAY STATE
    AH = A0h
Return: AL = display status (see #1130)
    BX = host window status (see #1131)
Program: Attachmate Extra! is a 3270 emulator by Attachmate Corporation
SeeAlso: AH=A1h

Bitfields for Attachmate Extra! display status:
Bit(s)    Description    (Table 1130)
 7    0=windowed, 1=enlarged
 6-3    current screen profile number 0-9
 2-0    active window number (0=PC, 1-4=host B-E, 5-6=notepad F-G)

Bitfields for host window status:
Bit(s)    Description    (Table 1131)
 15    reserved
 14    0=host E window installed, 1=not
 13    0=host E terminal on, 1=off
 12    0=host E window displayed, 1=not
 11    reserved
 10    0=host D window installed, 1=not
 9    0=host D terminal on, 1=off
 8    0=host D window displayed, 1=not
 7    reserved
 6    0=host C window installed, 1=not
 5    0=host C terminal on, 1=off
 4    0=host C window displayed, 1=not
 3    reserved
 2    0=host B window installed, 1=not
 1    0=host B terminal on, 1=off
 0    0=host B window displayed, 1=not
--------I-21A1-------------------------------
INT 21 - Attachmate Extra! - SET 3270 DISPLAY STATE
    AH = A1h
    AL = new display status byte (see #1130)
SeeAlso: AH=A0h,AH=A2h
--------v-21A1D5-----------------------------
INT 21 - VIRUS - "789"/"Filehider" - INSTALLATION CHECK
    AX = A1D5h
Return: AX = 900Dh if resident
SeeAlso: AX=9753h,AX=9AD5h,AX=A55Ah
--------I-21A2-------------------------------
INT 21 - Attachmate Extra! - SET HOST WINDOW STATE
    AH = A2h
    AL = new host window status byte (see #1132)
SeeAlso: AH=A1h

Bitfields for Attachmate Extra! host window status:
Bit(s)    Description    (Table 1132)
 7    0=power off, 1=power on
 6    0=not installed, 1=installed
 5-3    reserved
 2-0    window number 1-4=host B-E
--------I-21A3-------------------------------
INT 21 - Attachmate Extra! - SEND KEYSTROKES TO HOST WINDOW
    AH = A3h
    AL = window number (1-4=host B-E)
    CX = 0001h
    DS:BX -> keystroke buffer
    DL = zero if keystroke buffer contains host function code (see #1133),
          non-zero if keystroke buffer contains ASCII character
Return: CX = zero if character sent, non-zero if not
    BX incremented if CX=0

(Table 1133)
Values for Attachmate Extra! host function code:
 00h=reserved    10h=PF16    20h=Clear    30h=SysReq
 01h=PF1    11h=PF17    21h=Print    31h=ErInp
 02h=PF2    12h=PF18    22h=Left    32h=ErEof
 03h=PF3    13h=PF19    23h=Right    33h=Ident
 04h=PF4    14h=PF20    24h=Up        34h=Test
 05h=PF5    15h=PF21    25h=Down    35h=Reset
 06h=PF6    16h=PF22    26h=Home    36h=DevCncl
 07h=PF7    17h=PF23    27h=Fast Left    37h=Dup
 08h=PF8    18h=PF24    28h=Fast Right    38h=FldMark
 09h=PF9    19h=Alt on    29h=Bksp    39h=Enter
 0Ah=PF10    1Ah=Alt off    2Ah=Insert    3Ah=CrSel
 0Bh=PF11    1Bh=Shift on    2Bh=Delete
 0Ch=PF12    1Ch=Shift off    2Ch=Backtab
 0Dh=PF13    1Dh=PA1        2Dh=Tab
 0Eh=PF14    1Eh=PA2        2Eh=Newline
 0Fh=PF15    1Fh=PA3        2Fh=Attn
--------I-21A4-------------------------------
INT 21 - Attachmate Extra! - GET HOST WINDOW BUFFER ADDRESS
    AH = A4h
    AL = window number (1-4=host B-E)
Return: DS:BX -> 3270 display buffer
SeeAlso: AH=A5h,AH=B8h
--------I-21A5-------------------------------
INT 21 - Attachmate Extra! - GET HOST WINDOW CURSOR POSITION
    AH = A5h
    AL = window number (1-4=host B-E)
Return: BX = cursor position (80 * row + column, where 0:0 is upper left)
Note:    if the host window is configured with the Extended Attribute (EAB)
      feature, multiply the cursor position by 2 to obtain the byte offset
      into the display buffer
SeeAlso: AH=A4h
--------v-21A55A-----------------------------
INT 21 - VIRUS - "Eddie-2" - INSTALLATION CHECK
    AX = A55Ah
Return: AX = 5AA5h if resident
SeeAlso: AX=A1D5h,AX=AA00h
--------v-21AA00-----------------------------
INT 21 - VIRUS - "Blinker" - INSTALLATION CHECK
    AX = AA00h
Return: AX = 00AAh if resident
SeeAlso: AX=A55Ah,AX=AA03h
--------v-21AA03-----------------------------
INT 21 - VIRUS - "Backtime" - INSTALLATION CHECK
    AX = AA03h
Return: AX = 03AAh if resident
SeeAlso: AX=AA00h,AH=ABh
--------v-21AB-------------------------------
INT 21 - VIRUS - "600" or "Voronezh"-family - INSTALLATION CHECK
    AH = ABh
Return: AX = 5555h if resident
SeeAlso: AX=AA03h,AX=ABCDh,AX=BBBBh"VIRUS"
--------v-21ABCD-----------------------------
INT 21 - VIRUS - Major BBS - INSTALLATION CHECK
    AX = ABCDh
Return: AX = 1234h if installed
SeeAlso: AH=ABh"VIRUS",AX=ABCDh"SuperVirus"
--------v-21ABCD------------------------
INT 21 - VIRUS - "SuperVirus 2" - INSTALLATION CHECK
    AX = ABCDh
Return: AX = DCBAh if resident
SeeAlso: AX=ABCDh"VIRUS",AX=BBBBh"VIRUS"
--------I-21AF-------------------------------
INT 21 - Attachmate Extra! - GET TRANSLATE TABLE ADDRESS
    AH = AFh
Return: DS:BX -> translate tables (see #1134)

Format of Attachmate Extra! translate tables:
Offset    Size    Description    (Table 1134)
 00h 256 BYTEs    ASCII to 3270 buffer code translate table
100h 256 BYTEs    3270 buffer code to ASCII translate table
200h 256 BYTEs    3270 buffer code to EBCDIC translate table
300h 256 BYTEs    EBCDIC to 3270 buffer code translate table
--------v-21B3-------------------------------
INT 21 - VIRUS - "Requires" - INSTALLATION CHECK
    AH = B3h
Return: AX = 9051h if resident
SeeAlso: AH=7Fh"VIRUS",AX=B974h"VIRUS"
--------N-21B300-----------------------------
INT 21 U - Novell NetWare - CHECK LIP/PACKET SIGNING/IPX CHECKSUM SUPPORT???
    AX = B300h
Return: AX = 0000h if supported???
Note:    this function appeared with the packet signing/Large Internet Packets/
      IPX Checksum-aware NetWare shells
SeeAlso: AX=B301h,AX=B302h
--------N-21B301-----------------------------
INT 21 U - Novell NetWare - CHECK SIGNATURE LEVEL???
    AX = B301h
Return: AX = 0000h if supported???
        BX:CX indicate signature level (see #1135)
Note:    this function appeared with the packet signing/Large Internet Packets/
      IPX Checksum-aware NetWare shells
SeeAlso: AX=B300h,AX=B304h,#2154 at INT 2F/AX=7A20h/BX=0000h

(Table 1135)
Values for signature level indicator:
 0000h:0000h = signature level 0
 0002h:0000h = signature level 1
 0202h:0000h = signature level 2
 0202h:0202h = signature level 3
--------N-21B302-----------------------------
INT 21 U - Novell NetWare - START PACKET SIGNING
    AX = B302h
    CX = server connection (1-8)
    DS:SI -> 24-byte buffer containing ???
Return: ???
Notes:    this function appeared with the packet signing/Large Internet Packets/
      IPX Checksum-aware NetWare shells
    if packet signing is active, this call is required if and only if the
      last call successfully authenticated the workstation to the server
SeeAlso: AX=B300h,#2154
--------N-21B304-----------------------------
INT 21 U - Novell NetWare - SET SIGNATURE LEVEL
    AX = B304h
    BX:CX = new signature level (see AX=B301h)
Return: ???
Note:    this function appeared with the packet signing/Large Internet Packets/
      IPX Checksum-aware NetWare shells
SeeAlso: AX=B300h,AX=B301h,AX=B306h,#2154
--------N-21B306-----------------------------
INT 21 - Novell NetWare - RENEGOTIATE SECURITY LEVEL
    AX = B306h
    CX = server connection number (01h-08h)
Return: ???
Note:    this function appeared with the packet signing/Large Internet Packets/
      IPX Checksum-aware NetWare shells
SeeAlso: AX=B300h,AX=B304h,#2154
--------N-21B4-------------------------------
INT 21 U - Novell NetWare - "AttachHandle"
    AH = B4h
    DS:SI -> input buffer (see #1136)
Return: AX = DOS file handle or return code
Note:    this is an interface provided by NetWare to give DOS file access to
      NetWare files on non-DOS systems such as Macintosh, OS/2, and Unix
SeeAlso: AX=E909h

Format of Novell NetWare input buffer:
Offset    Size    Description    (Table 1136)
 00h    BYTE    "WorkFileServer"
 01h    BYTE    access code
 02h    DWORD    "OpenHandle"
 06h    WORD    "OpenHandleCount"
 08h    DWORD    "OpenFileSize"
Note:    the six bytes at 02h-07h appear to be the six-byte NetWare handle
      returned by AX=E909h
--------N-21B500-----------------------------
INT 21 U - Novell NetWare - VNETWARE.386 API - GET INSTANCE DATA
    AX = B500h
Return: ES:BX -> data
    CX = length
SeeAlso: AX=B501h,AX=B502h
--------N-21B501-----------------------------
INT 21 U - Novell NetWare - VNETWARE.386 API - END VIRTUAL MACHINE
    AX = B501h
SeeAlso: AX=B500h,AX=B502h
--------N-21B502-----------------------------
INT 21 U - Novell NetWare - VNETWARE.386 API - START VIRTUAL MACHINE
    AX = B502h
SeeAlso: AX=B500h,AX=B501h
--------N-21B5-------------------------------
INT 21 - Novell NetWare shell 3.01 - TASK MODE CONTROL
    AH = B5h
    AL = subfunction
        03h get task mode
        Return: AH = 00h
            AL = current task mode byte (see #1137)
        04h get task mode pointer
        Return: ES:BX -> task mode byte
Notes:    the task mode byte specifies how task cleanup should be performed, but
      is declared to be version-dependent
    allows a program to disable the automatic cleanup for programs managing
      task swapping, etc.

(Table 1137)
Values for NetWare task mode byte in version 3.01:
 00h-03h reserved
 04h     no task cleanup
--------N-21B505-----------------------------
INT 21 U - Novell NetWare - VNETWARE.386 API - SET VIRTUAL MACHINE ID
    AX = B505h
    ???
Return: ???
SeeAlso: AX=B502h,AX=B506h
--------N-21B506-----------------------------
INT 21 U - Novell NetWare - VNETWARE.386 API - GET VIRTUAL MACH SUPPORT LEVEL
    AX = B506h
Return: AX = ??? (0002h)
SeeAlso: AX=B505h
--------N-21B507-----------------------------
INT 21 - Novell NetWare - NetWare Shell - GET NUMBER OF PACKET BURST BUFFERS
    AX = B507h
Return: AL = number of packet burst buffers (configured at shell load time)
--------N-21B6-------------------------------
INT 21 - Novell NetWare - FILE SERVICES - EXTENDED FILE ATTRIBUTES
    AH = B6h
    AL = subfunction
        00h get extended file attributes
        01h set extended file attributes
        CL = extended file attributes (see #1138)
    DS:DX -> ASCIZ pathname (max 255 bytes)
Return: CF set on error
        AL = error code
        8Ch caller lacks privileges
        FEh not permitted to search directory
        FFh file not found
    CF clear if successful
        AL = 00h (success)
        CL = current extended file attributes (see #1138)
Note:    this function is supported by Advanced NetWare 2.1+
SeeAlso: AX=4300h,AH=E3h/SF=0Fh

Bitfields for NetWare extended file attributes:
Bit(s)    Description    (Table 1138)
 2-0    search mode (executables only)
    000 none (use shell's default search)
    001 search on all opens without path
    010 do not search
    011 search on read-only opens without path
    100 reserved
    101 search on all opens
    110 reserved
    111 search on all read-only opens
 3    reserved
 4    transactions on file tracked
 5    file's FAT indexed
 6    read audit (to be implemented)
 7    write audit (to be implemented)
--------N-21B7-------------------------------
INT 21 U - Novell NetWare - "HoldFileModeSet" (obsolete)
    AH = B7h
    AL = new value for HoldFileFlag
Return: AL = previous value of HoldFileFlag
Note:    this function provided backward compatibility with a bug in early
      DOS versions and CP/M, but is no longer used or supported
--------I-21B8-------------------------------
INT 21 - Attachmate Extra! - DISABLE HOST BUFFER UPDATES
    AH = B8h
    AL = window number (1-4=host B-E)
    DL = 01h
Notes:    only valid in CUT mode
    next AID keystroke (eg Enter) enables host buffer updates
SeeAlso: AH=A4h
--------N-21B800-----------------------------
INT 21 - Novell NetWare - PRINT SERVICES - GET DEFAULT CAPTURE FLAGS
    AX = B800h
    CX = size of reply buffer (01h-3Fh)
    ES:BX -> reply buffer for capture flags table (see #1139)
Return: AL = status
        00h successful
Note:    this function is supported by Advanced NetWare 2.0+
SeeAlso: AX=B801h,AX=B802h,AH=DFh/DL=00h,AH=DFh/DL=04h

Format of NetWare capture flags table:
Offset    Size    Description    (Table 1139)
 00h    BYTE    status (used internally, should be set to 00h)
 01h    BYTE    print flags (see #1140)
 02h    BYTE    tab size (01h-12h, default 08h)
 03h    BYTE    printer number on server (00h-04h, default 00h)
 04h    BYTE    number of copies to print (00h-FFh, default 01h)
 05h    BYTE    form type required in printer (default 00h)
 06h    BYTE    reserved
 07h 13 BYTEs    text to be placed on banner page
 14h    BYTE    reserved
 15h    BYTE    default local printer (00h = LPT1)
 16h    WORD    (big-endian) timeout in clock ticks for flushing capture file
          on inactivity, or 0000h to disable timeout
 18h    BYTE    flush capture file on LPT close if nonzero
 19h    WORD    (big-endian) maximum lines per page
 1Bh    WORD    (big-endian) maximum characters per line
 1Dh 13 BYTEs    name of form required in printer
 2Ah    BYTE    LPT capture flag
        00h inactive, FFh LPT device is being captured
 2Bh    BYTE    file capture flag
        00h if no file specified, FFh if capturing to file
 2Ch    BYTE    timing out (00h if no timeout in effect, FFh if timeout counter
          running)
 2Dh    DWORD    (big-endian) address of printer setup string
 31h    DWORD    (big-endian) address of printer reset string
 35h    BYTE    target connection ID
 36h    BYTE    capture in progress if FFh
 37h    BYTE    job queued for printing if FFh
 38h    BYTE    print job valid if FFh
 39h    DWORD    bindery object ID of print queue if previous byte FFh
 3Dh    WORD    (big-endian) print job number (1-999)

Bitfields for NetWare print flags:
Bit(s)    Description    (Table 1140)
 2    print capture file if interrupted by loss of connection
 3    no automatic form feed after print job
 6    printing control sequences interpreted by print service
 7    print banner page before capture file
--------N-21B801-----------------------------
INT 21 - Novell NetWare - PRINT SERVICES - SET DEFAULT CAPTURE FLAGS
    AX = B801h
    CX = size of buffer (01h-3Fh)
    ES:BX -> buffer containing capture flags table (see #1139)
Return: AL = status
        00h successful
Note:    this function is supported by Advanced NetWare 2.0+
SeeAlso: AX=B800h,AX=B803h,AH=DFh/DL=00h,AH=DFh/DL=04h
--------N-21B802-----------------------------
INT 21 - Novell NetWare - PRINT SERVICES - GET SPECIFIC CAPTURE FLAGS
    AX = B802h
    CX = size of reply buffer (01h-3Fh)
    DH = LPT port (00h-02h)
    ES:BX -> reply buffer for capture flags table (see #1139)
Return: AL = status
        00h successful
Note:    this function is supported by Advanced NetWare 2.1+
SeeAlso: AX=B800h,AX=B803h,AH=DFh/DL=00h,AH=DFh/DL=04h
--------N-21B803-----------------------------
INT 21 - Novell NetWare - PRINT SERVICES - SET SPECIFIC CAPTURE FLAGS
    AX = B803h
    CX = size of buffer (01h-3Fh)
    DH = LPT port (00h-02h)
    ES:BX -> buffer containing capture flags table (see #1139)
Return: AL = status
        00h successful
Note:    this function is supported by Advanced NetWare 2.1+
SeeAlso: AX=B800h,AX=B803h,AH=DFh/DL=00h,AH=DFh/DL=04h
--------N-21B804-----------------------------
INT 21 - Novell NetWare - PRINT SERVICES - GET DEFAULT LOCAL PRINTER
    AX = B804h
Return: DH = default LPT port (00h-02h)
Note:    this function is supported by Advanced NetWare 2.1+
SeeAlso: AX=B800h,AX=B805h,AH=DFh/DL=00h
--------N-21B805-----------------------------
INT 21 - Novell NetWare - PRINT SERVICES - SET DEFAULT LOCAL PRINTER
    AX = B805h
    DH = new default LPT port (00h-02h)
Return: AL = status
        00h successful
Note:    this function is supported by Advanced NetWare 2.1+
SeeAlso: AX=B800h,AX=B804h,AH=DFh/DL=00h
--------N-21B806-----------------------------
INT 21 - Novell NetWare - PRINT SERVICES - SET CAPTURE PRINT QUEUE
    AX = B806h
    DH = LPT port (00h-02h)
    BX:CX = print queue's object ID
Return: AL = status
        00h successful
        FFh job already set
Desc:    specify the print queue on which a print job is to be placed the next
      time a capture is started on the given printer port
Note:    this function is supported by Advanced NetWare 2.1+
SeeAlso: AX=B801h,AX=B807h,AH=E0h/SF=09h
--------N-21B807-----------------------------
INT 21 - Novell NetWare - PRINT SERVICES - SET CAPTURE PRINT JOB
    AX = B807h
    DH = LPT port (00h-02h)
    BX = job number (see AH=E3h/SF=68h)
    SI:DI:CX = NetWare file handle (see AH=E3h/SF=68h)
Return: AL = status
        00h successful
        FFh job already queued
Desc:    specify the capture file and print job to be used for subsequent
      output to the given printer port
Note:    this function is supported by Advanced NetWare 2.1+
SeeAlso: AX=B801h,AX=B806h,AH=E0h/SF=09h,AH=E3h/SF=68h
--------N-21B808-----------------------------
INT 21 - Novell NetWare - PRINT SERVICES - GET BANNER USER NAME
    AX = B808h
    ES:BX -> 12-byte buffer for user name
Return: AL = status
        00h successful
Desc:    get the user name which is printed on the banner page
Notes:    this function is supported by Advanced NetWare 2.1+
    the default name is the login name of the user
SeeAlso: AX=B809h
--------N-21B809-----------------------------
INT 21 - Novell NetWare - PRINT SERVICES - SET BANNER USER NAME
    AX = B809h
    ES:BX -> 12-byte buffer containing user name
Return: AL = status
        00h successful
Desc:    specify the user name which is printed on the banner page
Notes:    this function is supported by Advanced NetWare 2.1+
    the default name is the login name of the user
SeeAlso: AX=B808h
--------N-21B9-------------------------------
INT 21 U - Novell NetWare - "SpecialAttachableFunction"
    AH = B9h
    AL = FFh to hook this function
        ES:BX -> function to invoke on AH=B9h when AL<>FFh
Note:    this function is no longer used or supported by current versions of
      NetWare
--------v-21B974-----------------------------
INT 21 - VIRUS - "Tracker" - INSTALLATION CHECK
    AX = B974h
Return: AX = 2888h if resident
SeeAlso: AH=B3h"VIRUS",AH=D0h"VIRUS"
--------N-21BA-------------------------------
INT 21 U - Novell NetWare - "ReturnCommandComPointers"
    AH = BAh
Return: DX = environment segment
    ES:DI -> COMMAND.COM drive
Desc:    used to edit the COMSPEC and PATH variables in the master environment
      when mapping network drives
Note:    this function was documented in older Novell documents which are no
      longer available
--------N-21BB-------------------------------
INT 21 - Novell NetWare - WORKSTATION - SET END OF JOB STATUS
    AH = BBh
    AL = new EOJ flag
        00h disable EOJs
        01h enable EOJs
Return: AL = old EOJ flag
Desc:    specify whether the network shell should automatically generate an
      End of Job call when the root command processor regains control
Note:    this function is supported by NetWare 4.0+, Advanced NetWare 1.0+, and
      Alloy NTNX
SeeAlso: AH=19h,AH=D6h
--------v-21BBBB-----------------------------
INT 21 - VIRUS - "Hey You" - INSTALLATION CHECK
    AX = BBBBh
Return: AX = 6969h
SeeAlso: AH=ABh"VIRUS",AH=BEh"VIRUS"
--------N-21BC-------------------------------
INT 21 - Novell NetWare - SYNCHRONIZATION SERVICES - LOG PHYSICAL RECORD
    AH = BCh
    AL = flags (see #1142)
    BX = file handle
    CX:DX = starting offset in file
    SI:DI = length of region to lock
    BP = timeout in timer ticks (1/18 sec)
        0000h = don't wait if already locked
Return: AL = status (see #1141)
Desc:    add the specified physical record to the log table, optionally locking
      it
Note:    this function is supported by NetWare 4.6+, Advanced NetWare 1.0+, and
      Alloy NTNX
SeeAlso: AH=5Ch,AH=BDh,AH=BEh,AH=BFh,AH=C2h,AH=D0h

(Table 1141)
Values for NetWare status:
 00h    successful
 96h    no dynamic memory for file
 FEh    timed out
 FFh    failed

Bitfields for NetWare flags:
Bit(s)    Description    (Table 1142)
 0    lock as well as log record
 1    non-exclusive lock
--------N-21BD-------------------------------
INT 21 - Novell NetWare - SYNCHRONIZATION SERVICES - RELEASE PHYSICAL RECORD
    AH = BDh
    BX = file handle
    CX:DX = starting offset in file
    SI:DI = length of record
Return: AL = status
        00h successful
        FFh record not locked
Desc:    unlock the specified physical record but do not remove it from log
      table
Note:    this function is supported by NetWare 4.6+, Advanced NetWare 1.0+, and
      Alloy NTNX
SeeAlso: AH=BCh,AH=BEh"NetWare",AH=C0h,AH=C3h,AH=D2h
--------N-21BE-------------------------------
INT 21 - Novell NetWare - SYNCHRONIZATION SERVICES - CLEAR PHYSICAL RECORD
    AH = BEh
    BX = file handle
    CX:DX = starting offset within file
    SI:DI = record length in bytes
Return: AL = status
        00h successful
        FFh specified record not locked
Desc:    unlock the physical record and remove it from the log table
Note:    this function is supported by NetWare 4.6+, Advanced NetWare 1.0+, and
      Alloy NTNX
SeeAlso: AH=5Ch,AH=BCh,AH=BDh,AH=C1h,AH=C4h,AH=D4h
--------v-21BE-------------------------------
INT 21 - VIRUS - "Datalock" - INSTALLATION CHECK
    AH = BEh
Return: AX = 1234h if resident
SeeAlso: AX=BBBBh,AX=BE00h
--------v-21BE00-----------------------------
INT 21 - VIRUS - "USSR-1049" - INSTALLATION CHECK
    AX = BE00h
    CF set
Return: CF clear if resident
SeeAlso: AH=BEh"VIRUS",AH=C0h"VIRUS"
--------N-21BF-------------------------------
INT 21 O - Novell NetWare, Alloy NTNX - LOG/LOCK RECORD (FCB)
    AH = BFh
    AL = flags (see #1142)
    DS:DX -> opened FCB (see #0693 at AH=0Fh)
    BX:CX = offset
    BP = lock timeout in timer ticks (1/18 sec) if AL nonzero
    SI:DI = length
Return: AL = error code (see #1141)
Note:    this function was added in NetWare 4.6, but was removed some time prior
      to Advanced NetWare 2.15, and is no longer listed in current Novell
      documentation
SeeAlso: AH=BCh,AH=C0h"NetWare",AH=C2h"NetWare"
--------N-21C0-------------------------------
INT 21 O - Novell NetWare, Alloy NTNX - RELEASE RECORD (FCB)
    AH = C0h
    DS:DX -> non-extended FCB (see #0693 at AH=0Fh)
    BX:CX = offset
Return: AL = error code (see #1141)
Notes:    unlocks record but does not remove it from log table
    this function was added in NetWare 4.6, but was removed some time prior
      to Advanced NetWare 2.15, and is no longer listed in current Novell
      documentation
SeeAlso: AH=BDh,AH=BFh,AH=C1h"NetWare",AH=C3h
--------v-21C0-------------------------------
INT 21 - VIRUS - "Slow"/"Zerotime", "Solano" - INSTALLATION CHECK
    AH = C0h
Return: AX = 0300h if "Slow"/"Zerotime" resident
    AX = 1234h if "Solano" resident
SeeAlso: AX=BE00h,AX=C000h"VIRUS",AX=C301h"VIRUS"
--------v-21C000-----------------------------
INT 21 - VIRUS - "QUICKY" - INSTALLATION CHECK
    AX = C000h
    BX = most files infected by any other infected file
Return: AX = 76F3h if resident
SeeAlso: AH=C0h"VIRUS",AX=C001h,AX=C002h,AH=C1h"VIRUS"
--------v-21C001-----------------------------
INT 21 - VIRUS - "QUICKY" - TURN INFECTION OFF
    AX = C001h
Return: nothing
Note:    if the virus is already memory resident this call disables any
      further infections
SeeAlso: AX=C000h,AX=C002h
--------v-21C002-----------------------------
INT 21 - VIRUS - "QUICKY" - TURN INFECTION ON
    AX = C002h
Return: nothing
Note:    if the virus is already memory resident and infection is disabled,
      this call re-enables it
SeeAlso: AX=C000h,AX=C001h
--------N-21C1-------------------------------
INT 21 O - Novell NetWare, Alloy NTNX - CLEAR RECORD (FCB)
    AH = C1h
    DS:DX -> opened FCB (see #0693 at AH=0Fh)
    BX:CX = offset
Return: AL = error code (see #1141)
Note:    unlocks record and removes it from log table
    this function was added in NetWare 4.6, but was removed some time prior
      to Advanced NetWare, and is no longer listed in current Novell
      documentation
SeeAlso: AH=BEh,AH=C0h"NetWare",AH=C4h
--------v-21C1-------------------------------
INT 21 - VIRUS - "Solano" - ???
    AH = C1h
    ???
Return: ???
SeeAlso: AH=C0h"VIRUS"
--------N-21C2-------------------------------
INT 21 - Novell NetWare - SYNCHRONIZATION SERVICES - LOCK PHYSICAL RECORD SET
    AH = C2h
    AL = flags
        bit 1: non-exclusive lock
    BP = lock timeout in timer ticks (1/18 sec) 0000h = no wait
Return: AL = status
        00h successful
        FEh timed out
        FFh failed
Desc:    attempt to lock all physical records listed in the log table
Notes:    this function is supported by NetWare 4.6+, Advanced NetWare 1.0+, and
      Alloy NTNX
    status FFh will be returned if one or more physical records have been
      exclusively locked by another process
SeeAlso: AH=BFh,AH=C3h,AH=D1h
--------v-21C2-------------------------------
INT 21 - VIRUS - "Scott's Valley" - ???
    AH = C2h
    ???
Return: ???
SeeAlso: AH=C0h"VIRUS"
--------N-21C3-------------------------------
INT 21 - Novell NetWare - SYNCHRONIZATION SERVICES - RELEASE PHYS RECORD SET
    AH = C3h
Desc:    unlock all currently-locked physical records in the log table, but do
      not remove them from the table
Note:    this function is supported by NetWare 4.6+, Advanced NetWare 1.0+, and
      Alloy NTNX
SeeAlso: AH=BDh,AH=C0h,AH=C2h"NetWare",AH=C4h,AH=D3h
--------v-21C301DXF1F1-----------------------
INT 21 - VIRUS - "905"/"Backfont" - INSTALLATION CHECK
    AX = C301h
    DX = F1F1h
Return: DX = 0E0Eh if resident
SeeAlso: AH=C0h"VIRUS",AX=C500h"VIRUS"
--------N-21C4-------------------------------
INT 21 - Novell NetWare - SYNCHRONIZATION SERVICES - CLEAR PHYSICAL RECORD SET
    AH = C4h
Desc:    unlock all physical records in the log table and remove them from the
      log table
Note:    this function is supported by NetWare 4.6+, Advanced NetWare 1.0+, and
      Alloy NTNX
SeeAlso: AH=BEh,AH=C1h,AH=D5h
--------N-21C500-----------------------------
INT 21 - Novell NetWare - SYNCHRONIZATION SERVICES - OPEN SEMAPHORE
    AX = C500h
    DS:DX -> semaphore name (counted string, max 127 bytes)
    CL = initial value for semaphore
Return: AL = status
        00h successful
        BL = number of processes having semaphore open
        CX:DX = semaphore handle
        03h name length greater than 127
        (refer to Novell document FYI.A.4611)
        FEh invalid name length
        FFh invalid semaphore value
Notes:    this function is supported by NetWare 4.6+, Advanced NetWare 1.0+, and
      Alloy NTNX
    the semaphore's value is incremented by AX=C503h and decremented by
      AX=C502h
SeeAlso: AX=C501h,AX=C502h,AX=C503h,AX=C504h,AX=F220h/SF=00h
--------v-21C500-----------------------------
INT 21 - VIRUS - "Sverdlov" - INSTALLATION CHECK
    AX = C500h
Return: AX = 6731h if resident
SeeAlso: AX=C301h"VIRUS",AH=C6h"VIRUS"
--------N-21C501-----------------------------
INT 21 - Novell NetWare - SYNCHRONIZATION SERVICES - EXAMINE SEMAPHORE
    AX = C501h
    CX:DX = semaphore handle
Return: AL = status
        00h successful
        CX = semaphore value (-127 to 127)
        DL = count of processes which have the semaphore open
        FFh invalid handle
Note:    this function is supported by NetWare 4.6+, Advanced NetWare 1.0+, and
      Alloy NTNX
SeeAlso: AX=C500h"NetWare",AX=C502h,AX=C504h,AX=F220h/SF=01h
--------N-21C502-----------------------------
INT 21 - Novell NetWare - SYNCHRONIZATION SERVICES - WAIT ON SEMAPHORE
    AX = C502h
    CX:DX = semaphore handle
    BP = timeout limit in timer ticks (1/18 sec)
        0000h return immediately if semaphore already zero or negative
Return: AL = status
        00h successful
        FEh timeout
        FFh invalid handle
Desc:    decrement the semaphore's value, optionally waiting until its value
      becomes positive before decrementing
Note:    this function is supported by NetWare 4.6+, Advanced NetWare 1.0+, and
      Alloy NTNX
SeeAlso: AX=C500h"NetWare",AX=C501h,AX=C503h,AX=F220h/SF=02h
--------N-21C503-----------------------------
INT 21 - Novell NetWare - SYNCHRONIZATION SERVICES - SIGNAL SEMAPHORE
    AX = C503h
    CX:DX = semaphore handle
Return: AL = status
        00h successful
        01h semaphore value overflowed
        FFh invalid handle
Desc:    increment the semaphore's value and signal the first process (if any)
      in the queue waiting on the semaphore
Note:    this function is supported by NetWare 4.6+, Advanced NetWare 1.0+, and
      Alloy NTNX
SeeAlso: AX=C500h"NetWare",AX=C502h,AX=F220h/SF=03h
--------N-21C504-----------------------------
INT 21 - Novell NetWare - SYNCHRONIZATION SERVICES - CLOSE SEMAPHORE
    AX = C504h
    CX:DX = semaphore handle
Return: AL = status
        00h successful
        FFh invalid handle
Desc:    decrement the semaphore's open count, and delete the semaphore if the
      count reaches zero
Note:    this function is supported by NetWare 4.6+, Advanced NetWare 1.0+, and
      Alloy NTNX
SeeAlso: AX=C500h"NetWare",AX=C501h,AX=F220h/SF=04h
--------N-21C6-------------------------------
INT 21 - Novell NetWare - SYNCHRONIZATION SERVICES - GET OR SET LOCK MODE
    AH = C6h
    AL = subfunction
        00h set old "compatibility" mode (default)
        01h set new extended locks mode
        02h get lock mode
Return: AL = current lock mode
Note:    this function is supported by NetWare 4.6+, Advanced NetWare 1.0+, and
      Alloy NTNX
    the locking mode should be 01h for NetWare 4.61+ and Advanced
      NetWare 1.0+ locking calls, and 00h for all older calls
SeeAlso: AH=BCh,AH=C4h,AH=D0h
--------v-21C6-------------------------------
INT 21 - VIRUS - "Socha" - INSTALLATION CHECK
    AH = C6h
Return: AL = 55h if resident
SeeAlso: AX=C500h"VIRUS",AX=C603h
--------v-21C603-----------------------------
INT 21 - VIRUS - "Yankee Doodle" or "MLTI" - INSTALLATION CHECK
    AX = C603h
    BX = version number (002Ch or 002Dh)
    CF set
Return: CF clear if resident
    ZF set if resident and input BX matches version
SeeAlso: AX=C500h"VIRUS",AX=C700h"VIRUS"
--------N-21C700-----------------------------
INT 21 - Novell NetWare - TRANSACTION TRACKING SYSTEM - BEGIN TRANSACTION
    AX = C700h
Return: CF clear if successful
        AL = 00h
    CF set on error
        AL = error code
        96h out of memory
        FEh implicit transaction already active, converted to explicit
        FFh explicit transaction already active
Note:    this function is supported by NetWare 4.0+ and Advanced NetWare 1.0+
SeeAlso: AX=C701h,AX=C702h,AX=C703h,AX=F222h/SF=01h
--------v-21C700-----------------------------
INT 21 - VIRUS - "MH-757" - INSTALLATION CHECK
    AX = C700h
Return: AL = 07h if resident
SeeAlso: AX=C603h"VIRUS",AH=CBh"VIRUS"
--------N-21C701-----------------------------
INT 21 - Novell NetWare - TRANSACTION TRACKING SYSTEM - END TRANSACTION
    AX = C701h
Return: AL = status (00h,FDh-FFh) (see #1143)
        00h successful
        CX:DX = transaction number
    CF clear except when AL=FFh
Note:    this function is supported by NetWare 4.0+ and Advanced NetWare 1.0+
SeeAlso: AX=C700h"NetWare",AX=C703h,AX=F222h/SF=02h

(Table 1143)
Values for NetWare TTS status:
 00h    successful
 FDh    transaction tracking disabled
 FEh    transaction ended records locked
 FFh    no explicit transaction active
--------N-21C702-----------------------------
INT 21 - Novell NetWare - TRANSACTION TRACKING SYSTEM - INSTALLATION CHECK
    AX = C702h
Return: AL = status
        00h not available
        01h available
        FDh available but disabled
Desc:    determine whether the default file server supports TTS
Note:    this function is supported by NetWare 4.0+ and Advanced NetWare 1.0+
SeeAlso: AX=C700h,AX=C701h,AX=C703h,AX=F222h/SF=00h
--------N-21C703-----------------------------
INT 21 - Novell NetWare - TRANSACTION TRACKING SYSTEM - ABORT TRANSACTION
    AX = C703h
Return: CF clear if successful
        AL = 00h
    CF set on error
        AL = error code (FDh-FFh) (see #1143)
Note:    this function is supported by NetWare 4.0+ and Advanced NetWare 1.0+
SeeAlso: AX=C700h"NetWare",AX=C701h,AX=C704h,AX=F222h/SF=03h
--------N-21C704-----------------------------
INT 21 - Novell NetWare - TRANSACTION TRACKING SYSTEM - TRANSACTION STATUS
    AX = C704h
    CX:DX = transaction number (see AX=C701h)
Return: AL = status
        00h successful
        FFh not yet written to disk
Desc:    verify that a transaction has actually been written to disk
Notes:    this function is supported by NetWare 4.0+ and Advanced NetWare 1.0+
    transactions are written to disk in the order in which they are ended,
      but it may take as much as five seconds for the data to be written
SeeAlso: AX=C700h"NetWare",AX=C701h,AX=C703h,AX=F222h/SF=04h
--------N-21C705-----------------------------
INT 21 - Novell NetWare - TRANSACTION TRACKING SYSTEM - GET APPLICTN THRESHOLDS
    AX = C705h
Return: AL = status
        00h successful
    CL = maximum logical record locks (default 0)
    CH = maximum physical record locks (default 0)
Desc:    get the per-application limits on record locks allowed before an
      implicit transaction is begun
Notes:    this function is supported by NetWare 4.0+ and Advanced NetWare 1.0+
    if either limit is FFh, implicit transactions are disabled for the
      corresponding lock type
SeeAlso: AX=C706h,AX=C707h,AX=F222h/SF=05h
--------N-21C706-----------------------------
INT 21 - Novell NetWare - TRANSACTION TRACKING SYSTEM - SET APPLICTN THRESHOLDS
    AX = C706h
    CL = maximum logical record locks (default 0)
    CH = maximum physical record locks (default 0)
Return: AL = status
        00h successful
Desc:    specify the per-application limits on record locks allowed before an
      implicit transaction is begun
Notes:    this function is supported by NetWare 4.0+ and Advanced NetWare 1.0+
    if either limit is set to FFh, implicit transactions are disabled for
      the corresponding lock type
SeeAlso: AX=C705h,AX=C708h,AX=F222h/SF=06h
--------N-21C707-----------------------------
INT 21 - Novell NetWare - TRANSACTION TRACKING SYSTEM - GET WORKSTN THRESHOLDS
    AX = C707h
Return: AL = status
        00h successful
    CL = maximum logical record locks (default 0)
    CH = maximum physical record locks (default 0)
Desc:    get the per-workstation limits on record locks allowed before an
      implicit transaction is begun
Notes:    this function is supported by NetWare 4.0+ and Advanced NetWare 1.0+
    if either limit is FFh, implicit transactions are disabled for the
      corresponding lock type
SeeAlso: AX=C705h,AX=C708h,AX=F222h/SF=07h
--------N-21C708-----------------------------
INT 21 - Novell NetWare - TRANSACTION TRACKING SYSTEM - SET WORKSTN THRESHOLDS
    AX = C708h
    CL = maximum logical record locks (default 0)
    CH = maximum physical record locks (default 0)
Return: AL = status
        00h successful
Desc:    specify the per-workstation limits on record locks allowed before an
      implicit transaction is begun
Notes:    this function is supported by NetWare 4.0+ and Advanced NetWare 1.0+
    if either limit is set to FFh, implicit transactions are disabled for
      the corresponding lock type
SeeAlso: AX=C706h,AX=C707h,AX=F222h/SF=08h
--------N-21C8-------------------------------
INT 21 O - Novell NetWare - BEGIN LOGICAL FILE LOCKING
    AH = C8h
    if function C6h lock mode 00h:
        DL = mode
        00h no wait
        01h wait
    if function C6h lock mode 01h:
        BP = timeout in timer ticks (1/18 sec)
Return: AL = error code
Desc:    used to provide TTS support for applications which are not aware of
      Novell's Transaction Tracking System
Note:    this function was added in NetWare 4.0, but was removed some time prior
      to Advanced NetWare 2.15, and is no longer listed in current Novell
      documentation
SeeAlso: AH=C9h
--------N-21C9-------------------------------
INT 21 O - Novell NetWare - END LOGICAL FILE LOCKING
    AH = C9h
Return: AL = error code
Desc:    used to provide TTS support for applications which are not aware of
      Novell's Transaction Tracking System
Note:    this function was added in NetWare 4.0, but was removed some time prior
      to Advanced NetWare 2.15, and is no longer listed in current Novell
      documentation
SeeAlso: AH=C8h
--------N-21CA-------------------------------
INT 21 O - Novell NetWare, Alloy NTNX - LOG/LOCK PERSONAL FILE (FCB)
    AH = CAh
    DS:DX -> FCB (see #0693 at AH=0Fh)
    if function C6h lock mode 01h:
        AL = log and lock flag
        00h log file only
        01h lock as well as log file
        BP = lock timeout in timer ticks (1/18 sec)
Return: AL = error code
        00h successful
        96h no dynamic memory for file
        FEh timeout
        FFh failed
Desc:    provides file locking support for FCBs
Note:    this function was added in NetWare 4.0, but was removed some time prior
      to Advanced NetWare 2.15, and is no longer listed in current Novell
      documentation
SeeAlso: AH=CBh
--------v-21CA15-----------------------------
INT 21 - VIRUS - "Piter" - ???
    AX = CA15h
    ???
Return: ???
SeeAlso: AH=CCh"VIRUS"
--------N-21CB-------------------------------
INT 21 - Novell NetWare - SYNCHRONIZATION SERVICES - LOCK FILE SET
    AH = CBh
    if function C6h lock mode 00h:
        DL = mode (00h no wait, 01h wait)
    if function C6h lock mode 01h:
        BP = lock timeout in timer ticks (1/18 sec), 0000h = no wait
Return: AL = status (00h,FEh,FFh) (see #1144)
Desc:    attempt to lock all files listed in the log table
Notes:    this function is supported by NetWare 4.0+, Advanced NetWare 1.0+, and
      Alloy NTNX
    status FFh will be returned if one or more of the files have already
      been exclusively locked by another process
SeeAlso: AH=CAh,AH=CDh,AH=D1h,AH=EBh

(Table 1144)
Values for NetWare status:
 00h    successful
 FEh    timed out
 FFh    failed
--------v-21CB-------------------------------
INT 21 - VIRUS - "Milous" - INSTALLATION CHECK
    AH = CBh
Return: AL = 07h if resident
SeeAlso: AX=C700h"VIRUS",AX=CB02h
--------v-21CB02-----------------------------
INT 21 - VIRUS - "Witcode" - INSTALLATION CHECK
    AX = CB02h
Return: AX = 02CBh if resident
SeeAlso: AH=CBh"VIRUS",AH=CCh"VIRUS"
--------N-21CC-------------------------------
INT 21 O - Novell NetWare, Alloy NTNX - RELEASE FILE (FCB)
    AH = CCh
    DS:DX -> FCB (see #0693 at AH=0Fh)
Return: none
Desc:    unlocks file, but does not remove it from the log table or close it
Note:    this function was added in NetWare 4.0, but was removed some time prior
      to Advanced NetWare 2.15, and is no longer listed in current Novell
      documentation
SeeAlso: AH=CAh,AH=CDh
--------v-21CC-------------------------------
INT 21 - VIRUS - "Westwood" - INSTALLATION CHECK
    AH = CCh
Return: AX = 0700h if resident
SeeAlso: AX=CB02h,AH=CDh"VIRUS",AX=D000h"VIRUS"
--------N-21CD-------------------------------
INT 21 - Novell NetWare - SYNCHRONIZATION SERVICES - RELEASE FILE SET
    AH = CDh
Return: none
Desc:    unlock all files listed in the log table, but don't remove them from
      the table
Note:    this function is supported by NetWare 4.0+, Advanced NetWare 1.0+, and
      Alloy NTNX
SeeAlso: AH=CBh,AH=CCh,AH=CFh,AH=D3h
--------v-21CD-------------------------------
INT 21 - VIRUS - "Westwood" - ???
    AH = CDh
    ???
Return: ???
SeeAlso: AH=CCh"VIRUS"
--------N-21CE-------------------------------
INT 21 O - Novell NetWare, Alloy NTNX - CLEAR FILE (FCB)
    AH = CEh
    DS:DX -> FCB (see #0693 at AH=0Fh)
Return: AL = error code
Desc:    unlocks file and removes it from log table, then closes all opened and
      logged occurrences
Note:    this function was added in NetWare 4.0, but was removed some time prior
      to Advanced NetWare 2.15, and is no longer listed in current Novell
      documentation
SeeAlso: AH=CAh,AH=CFh,AH=EDh"NetWare"
--------N-21CF-------------------------------
INT 21 - LANstep - ???
    AH = CFh
    ???
Return: ???
Program: LANstep is a redesign of the Waterloo Microsystems PORT network
--------N-21CF-------------------------------
INT 21 - Novell NetWare - SYNCHRONIZATION SERVICES - CLEAR FILE SET
    AH = CFh
Return: AL = 00h
Desc:    unlock and remove all files from log table
Note:    this function is supported by NetWare 4.0+, Advanced NetWare 1.0+, and
      Alloy NTNX
SeeAlso: AH=CAh,AH=CEh,AH=EBh"NetWare"
--------N-21D0-------------------------------
INT 21 - Novell NetWare - SYNCHRONIZATION SERVICES - LOG LOGICAL RECORD
    AH = D0h
    DS:DX -> record string (counted string, max 99 data bytes)
    if function C6h lock mode 01h: (Novell, NTNX only)
        AL = flags
        bit 0: lock as well as log the record
        bit 1: non-exclusive lock
        BP = lock timeout in timer ticks (1/18 sec)
Return: AL = status
        00h successful
        96h no dynamic memory for file
        FEh timed out
        FFh unsuccessful
Desc:    add the specified logical record name to the log table, and optionally
      lock the record
Notes:    this function is supported by NetWare 4.6+, Advanced NetWare 1.0+,
      Banyan VINES, and Alloy NTNX
    locks on logical record names are advisory and may be ignored by other
      applications
SeeAlso: AH=BCh,AH=D1h,AH=D2h,AH=D4h,AH=EBh
--------v-21D0-------------------------------
INT 21 - VIRUS - "MALAGA" - INSTALLATION CHECK
    AH = D0h
Return: AX = 00D0h if resident
SeeAlso: AH=B3h"VIRUS",AH=D0h"ANTIARJ",AX=D000h"VIRUS"
--------v-21D0-----------------------------
INT 21 - VIRUS - "ANTIARJ" -INSTALLATION CHECK
    AH = D0h
Return: AH = D1h if resident
SeeAlso: AH=D0h"MALAGA"
--------v-21D000-----------------------------
INT 21 - VIRUS - "Fellowship" - INSTALLATION CHECK
    AX = D000h
Return: BX = 1234h if resident
SeeAlso: AH=CCh"VIRUS",AH=D0h"ANTIARJ",AX=D000h"Warlock",AH=D5h"VIRUS",AX=D5AAh
--------v-21D000-----------------------------
INT 21 - VIRUS - "Warlock" - INSTALLATION CHECK
    AX = D000h
    CF clear
Return: CF set if resident (normal DOS return would be CF clear)
SeeAlso: AX=D000h"VIRUS",AH=D5h"VIRUS"
--------N-21D1-------------------------------
INT 21 - Novell NetWare - SYNCHRONIZATION SERVICES - LOCK LOGICAL RECORD SET
    AH = D1h
    AL = lock type (00h exclusive, 01h shareable)
    if function C6h lock mode 00h:
        DL = mode (00h no wait, 01h wait)
    if function C6h lock mode 01h: (Novell only)
        BP = lock timeout in timer ticks (1/18 sec), 0000h no wait
Return: AL = status (see #1144)
Desc:    attempt to lock all logical record names listed in the log table
Notes:    this function is supported by NetWare 4.6+, Advanced NetWare 1.0+,
      Banyan VINES, and Alloy NTNX
    status FFh will be returned if one or more logical records have been
      exclusively locked by another process
    locks on logical record names are advisory and may be ignored by other
      applications
SeeAlso: AH=C2h,AH=CBh,AH=D0h,AH=D3h,AH=D5h
--------N-21D2-------------------------------
INT 21 - Novell NetWare - SYNCHRONIZATION SERVICES - RELEASE LOGICAL RECORD
    AH = D2h
    DS:DX -> semaphore identifier (counted string up to 99 chars long)
Return: AL = status
        00h successful
        FFh no such record
Desc:    unlock the logical record name but do not remove it from the log table
Notes:    this function is supported by NetWare 4.0+, Advanced NetWare 1.0+,
      Banyan VINES, and Alloy NTNX
    locks on logical record names are advisory and may be ignored by other
      applications
SeeAlso: AH=BDh,AH=D0h,AH=D3h,AH=D4h
--------v-21D2-------------------------------
INT 21 - VIRUS???
    AH = D2h
    ???
Return: ???
Note:    this call is intercepted by the Search&Destroy SDRes v27.03 bundled
      with Novell DOS 7, and is presumably some virus's installation check
SeeAlso: AH=4Ah/BX=00B6h
--------N-21D3-------------------------------
INT 21 - Novell NetWare - SYNCHRONIZATION SERVICES - RELEASE LOGICAL RECORD SET
    AH = D3h
Desc:    unlock all currently-locked logical record names in the log table, but
      do not remove them from the table
Notes:    this function is supported by NetWare 4.0+, Advanced NetWare 1.0+,
      Banyan VINES, and Alloy NTNX
    locks on logical record names are advisory and may be ignored by other
      applications
SeeAlso: AH=C3h,AH=CDh,AH=D1h,AH=D2h,AH=D5h
--------N-21D4-------------------------------
INT 21 - Novell NetWare - SYNCHRONIZATION SERVICES - CLEAR LOGICAL RECORD
    AH = D4h
    DS:DX -> logical record name (counted string up to 99 chars long)
Return: AL = status (00h,FFh) (see #1145)
Desc:    unlock and remove the logical record name from the log table
Notes:    this function is supported by NetWare 4.0+, Advanced NetWare 1.0+,
      Banyan VINES, and Alloy NTNX
    locks on logical record names are advisory and may be ignored by other
      applications
SeeAlso: AH=BEh,AH=D0h,AH=D2h,AH=D5h

(Table 1145)
Values for NetWare status:
 00h    successful
 FFh    no such record name
--------N-21D5-------------------------------
INT 21 - Novell NetWare - SYNCHRONIZATION SERVICES - CLEAR LOGICAL RECORD SET
    AH = D5h
Return: AL = error code (00h,FFh) (see #1145)
Desc:    unlock and remove all logical record name from the log table
Notes:    this function is supported by NetWare 4.0+, Advanced NetWare 1.0+,
      Banyan VINES, and Alloy NTNX
    locks on logical record names are advisory and may be ignored by other
      applications
SeeAlso: AH=D1h,AH=D3h,AH=D4h
--------v-21D5-------------------------------
INT 21 - VIRUS - "Carfield" - ???
    AH = D5h
    ???
Return: ???
SeeAlso: AX=D5AAh,AH=F3h"Carfield"
--------v-21D5AA-----------------------------
INT 21 - VIRUS - "Diamond-A", "Diamond-B" - INSTALLATION CHECK
    AX = D5AAh
Return: AX = 2A55h if "Diamond-A" resident
    AX = 2A03h if "Diamond-B"-family virus resident
SeeAlso: AX=D000h,AH=D5h"VIRUS",AX=D5AAh/BP=DEAAh
--------v-21D5AABPDEAA-----------------------
INT 21 - VIRUS - "Dir" - INSTALLATION CHECK
    AX = D5AAh
    BP = DEAAh
Return: SI = 4321h if resident
SeeAlso: AX=D5AAh,AX=DADAh"VIRUS"
--------N-21D6-------------------------------
INT 21 - Novell NetWare - WORKSTATION - END OF JOB
    AH = D6h
    BX = job flag (0000h current job, FFFFh all processes on workstation)
Return: AL = error code
Desc:    unlocks and clears all locked or logged files and records held by the
      process(es), closes all files, resets error and lock modes, and
      releases all network resources
Note:    this function is supported by NetWare 4.0+, Advanced NetWare 1.0+, and
      Alloy NTNX
SeeAlso: AH=BBh"NetWare",AH=D7h
--------N-21D7-------------------------------
INT 21 - Novell NetWare - CONNECTION SERVICES - SYSTEM LOGOUT
    AH = D7h
Return: AL = error code
Desc:    this function closes the caller's open files, logs it out from all
      file servers, detaches the workstation from all non-default file
      servers, and maps a drive to the default server's SYS:LOGIN directory
Note:    this function is supported by NetWare 4.0+, Advanced NetWare 1.0+, and
      Alloy NTNX
SeeAlso: AH=D6h,AH=E3h/SF=14h,AH=F1h"NetWare"
--------N-21D8-------------------------------
INT 21 - Novell NetWare, Banyan VINES - ALLOCATE RESOURCE
    AH = D8h
    DL = resource number
Return: AL = status (00h successful, FFh unsucessful)
Note:    this function is no longer used or supported by NetWare, and is not
      documented in Novell documents
SeeAlso: AH=D9h
--------N-21D9-------------------------------
INT 21 - Novell NetWare, Banyan VINES - DEALLOCATE RESOURCE
    AH = D9h
    DL = resource number
Return: AL = status (00h successful, FFh unsucessful)
Note:    this function is no longer used or supported by NetWare, and is not
      documented in Novell documents
SeeAlso: AH=D8h
--------N-21DA-------------------------------
INT 21 - Novell NetWare - DIRECTORY SERVICES - GET VOLUME INFO WITH NUMBER
    AH = DAh
    DL = volume number
    ES:DI -> reply buffer (see #1146)
Return: AL = 00h
Notes:    this function is supported by NetWare 4.0+ and Advanced NetWare 1.0+
    operator console rights are not required to make this call
    reported total blocks and total unused blocks include the Hot Fix
      Table; the NetWare shell's implementation of INT 21/AH=36h will
      report values larger than 268MB as 268MB.
SeeAlso: AH=36h,AH=E2h/SF=15h,AH=E3h/SF=E9h

Format of NetWare reply buffer:
Offset    Size    Description    (Table 1146)
 00h    WORD    sectors/block
 02h    WORD    total blocks on volume
 04h    WORD    unused blocks
 06h    WORD    total directory entries
 08h    WORD    unused directory entries
 0Ah 16 BYTEs    volume name, null padded
 1Ah    WORD    removable flag, 0000h = not removable
Note:    all words are big-endian
--------v-21DADA-----------------------------
INT 21 - VIRUS - "Gotcha" - INSTALLATION CHECK
    AX = DADAh
Return: AH = A5h
SeeAlso: AX=D5AAh,AX=DAFEh"VIRUS"
--------v-21DAFE-----------------------------
INT 21 - VIRUS - "Plovdiv 1.3" - INSTALLATION CHECK
    AX = DAFEh
Return: AX = 1234h if resident
SeeAlso: AX=DADAh,AH=DDh"VIRUS",AH=DEh"VIRUS"
--------N-21DB-------------------------------
INT 21 - Novell NetWare - WORKSTATION - GET NUMBER OF LOCAL DRIVES
    AH = DBh
Return: AL = number of local disks as set by LASTDRIVE in CONFIG.SYS
Note:    this function is supported by NetWare 4.0+, Advanced NetWare 1.0+, and
      Alloy NTNX
SeeAlso: AH=0Eh
--------N-21DC-------------------------------
INT 21 - Novell NetWare - CONNECTION SERVICES - GET CONNECTION NUMBER
    AH = DCh
Return: AL = logical connection number
        00h if NetWare not loaded or this machine is a non-dedicated server
    CX = station number in ASCII (CL = first digit)
Notes:    this function is supported by NetWare 4.0+, Banyan VINES, and Alloy
      NTNX
    station number only unique for those PCs connected to same semaphore
      service
SeeAlso: AH=F2h"NetWare"
--------d-21DC-------------------------------
INT 21 - PCMag PCMANAGE/DCOMPRES - TURN ON/OFF
    AH = DCh
    DX = state
        0000h turn on
        0001h turn off
SeeAlso: AX=FEDCh
--------v-21DC28-----------------------------
INT 21 - VIRUS - "Monika" - INSTALLATION CHECK
    AX = DC28h
Return: AX = 1973h if resident
SeeAlso: AX=D000h"VIRUS",AX=DCBAh"VIRUS"
--------v-21DCBA-----------------------------
INT 21 - VIRUS - "Red Spider" - INSTALLATION CHECK
    AX = DCBAh
Return: AX = ABCDh if resident
SeeAlso: AX=DC28h"VIRUS",AX=DEFEh"VIRUS"
--------N-21DD-------------------------------
INT 21 - Novell NetWare - WORKSTATION - SET NetWare ERROR MODE
    AH = DDh
    DL = error mode
        00h invoke INT 24 on critical I/O errors (default)
        01h return NetWare extended error code in AL
        02h return error code in AL, mapped to standard DOS error codes
Return: AL = previous error mode
Note:    this function is supported by Advanced NetWare 2.0+
SeeAlso: INT 24
--------v-21DD-------------------------------
INT 21 - VIRUS - "Jerusalem"-family - RELOCATE VIRUS???
    AH = DDh
    CX = number of bytes to copy
    DS:SI -> source of copy
    ES:DI -> destination of copy
Return: does not return normally; return address is caller's CS:0100h with
      AX = ???
SeeAlso: AX=DDEFh,AH=E0h"VIRUS",AH=EEh"VIRUS"
--------v-21DDEF------------------------
INT 21 - VIRUS- "GOLGI" - INSTALLATION CHECK
    AX = DDEFh
Return: AX = EFDDh if resident
SeeAlso: AH=DDh"VIRUS",AH=DEh"VIRUS"
--------v-21DE-------------------------------
INT 21 - VIRUS - "Durban" - INSTALLATION CHECK
    AH = DEh
Return: AH = DFh if resident
SeeAlso: AX=DAFEh,AX=DDEFh,AH=DEh"April 1st",AX=DEADh"90210"
--------v-21DE-------------------------------
INT 21 - VIRUS - "April 1st EXE" - ???
    AH = DEh
    ???
Return: ???
SeeAlso: AH=DEh"Durban",AX=DEADh"90210"
--------N-21DE-------------------------------
INT 21 - Novell NetWare - MESSAGE SERVICES - SET BROADCAST MODE
    AH = DEh
    DL = broadcast mode
        00h receive server and workstation broadcasts (default)
        01h receive server broadcasts, discard user messages
        02h store server broadcasts for retrieval
        03h store all broadcasts for retrieval
Return: AL = new broadcast mode
Note:    this function is supported by NetWare 4.0+ and Advanced NetWare 1.0+
--------N-21DE--DL04-------------------------
INT 21 - Novell NetWare - MESSAGE SERVICES - GET BROADCAST MODE
    AH = DEh
    DL = 04h
Return: AL = current broadcast mode
        00h receive server and workstation broadcasts (default)
        01h receive server broadcasts, discard user message
        02h store server broadcasts for retrieval
        03h store all broadcasts for retrieval
Note:    this function is supported by NetWare 4.0+ and Advanced NetWare 1.0+
--------N-21DE-------------------------------
INT 21 - Novell NetWare - SHELL TIMER INTERRUPT CHECKS
    AH = DEh
    DL = function
        05h disable shell timer interrupt checks
        06h enable shell timer interrupt checks
Return: ???
Note:    this function was added in NetWare 4.0, but is not listed in current
      Novell documentation and is probably no longer supported
--------v-21DEAD------------------------
INT 21 - VIRUS - "90210" - INSTALLATION CHECK
    AX = DEADh
Return: AX = AAAAh if resident
SeeAlso: AH=DEh"April 1st",AX=DEADh"Shifting",AX=DEDEh"VIRUS"
--------v-21DEAD------------------------
INT 21 - VIRUS - "Shifting Objective" - RELOCATE CODE ???
    AX = DEADh
SeeAlso: AX=FEADh
SeeAlso: AX=DEADh"90210",AX=DEDEh"VIRUS"
--------v-21DEDE-----------------------------
INT 21 - VIRUS - "Brothers" - INSTALLATION CHECK
    AX = DEDEh
Return: AH = 41h if resident
SeeAlso: AX=DEADh"Shifting",AX=DEFEh"VIRUS"
--------v-21DEFE-----------------------------
INT 21 - VIRUS - "Maze" - INSTALLATION CHECK
    AX = DEFEh
Return: AX = ABCDh if resident
SeeAlso: AX=DCBAh"VIRUS",AX=DEDEh"VIRUS",AH=E0h"VIRUS"
--------N-21DF--DL00-------------------------
INT 21 - Novell NetWare - PRINT SERVICES - START LPT CAPTURE
    AH = DFh
    DL = 00h
Return: AL = status
        00h successful
Desc:    this function redirects the default LPT to a capture file on the file
      server
Note:    this function is supported by NetWare 4.0+, Advanced NetWare 1.0+, and
      Alloy NTNX; under NTNX, it sends a print break (see INT 17/AH=84h)
    a print job is queued when the first character of output is captured
SeeAlso: AX=B800h,AX=B804h,AH=DFh/DL=01h,AH=DFh/DL=02h,AH=DFh/DL=03h
SeeAlso: AH=DFh/DL=04h,AX=F003h
--------N-21DF--DL01-------------------------
INT 21 - Novell NetWare - PRINT SERVICES - END LPT CAPTURE
    AH = DFh
    DL = 01h
Return: AL = status
        00h successful
Desc:    stop redirecting the default LPT, close the capture file, and release
      the job in the print queue for printing
Note:    this function is supported by NetWare 4.0+, Advanced NetWare 1.0+, and
      Alloy NTNX; under NTNX, it sends a print break (see INT 17/AH=84h)
    after this call, the default LPT defaults to local printing
SeeAlso: AH=DFh/DL=00h,AH=DFh/DL=02h,AH=DFh/DL=03h,AH=DFh/DL=05h
--------N-21DF--DL02-------------------------
INT 21 - Novell NetWare - PRINT SERVICES - CANCEL LPT CAPTURE
    AH = DFh
    DL = 02h
Return: AL = status
        00h successful
Desc:    this function ends the capture of the default LPT, removes the job from
      the print queue, and deletes the capture file unless it is a
      permanent capture file
Notes:    this function is supported by NetWare 4.0+, Advanced NetWare 1.0+, and
      Alloy NTNX; under NTNX, it sends a print break (see INT 17/AH=84h)
    after this call, the default LPT defaults to local printing
SeeAlso: AH=DFh/DL=00h,AH=DFh/DL=06h
--------N-21DF--DL03-------------------------
INT 21 - Novell NetWare - PRINT SERVICES - FLUSH LPT CAPTURE
    AH = DFh
    DL = 03h
Return: AL = status
        00h successful
Desc:    this function closes the current capture file for the default LPT
      and starts printing it if it is not a permanent capture file
Notes:    this function is supported by NetWare 4.0+, Advanced NetWare 1.0+, and
      Alloy NTNX; under NTNX, it sends a print break (see INT 17/AH=84h)
    if more data is sent to the LPT port after this call, a new capture
      file will be opeend
SeeAlso: AH=DFh/DL=00h,AH=DFh/DL=01h,AH=DFh/DL=02h,AH=DFh/DL=07h
--------N-21DF--DL04-------------------------
INT 21 - Novell NetWare - PRINT SERVICES - START SPECIFIC LPT CAPTURE
    AH = DFh
    DL = 04h
    DH = LPT port (00h-02h)
Return: AL = status
        00h successful
Desc:    this function redirects the specified LPT to a capture file on the file
      server
Notes:    this function is supported by Advanced NetWare 2.1+
    a print job is queued when the first character of output is captured
SeeAlso: AX=B800h,AH=DFh/DL=00h,AH=DFh/DL=05h,AH=DFh/DL=06h,AH=DFh/DL=07h
SeeAlso: AX=F003h
--------N-21DF--DL05-------------------------
INT 21 - Novell NetWare - PRINT SERVICES - END SPECIFIC LPT CAPTURE
    AH = DFh
    DL = 05h
    DH = LPT port (00h-02h)
Return: AL = status
        00h successful
Desc:    stop redirecting the specified LPT, close the capture file, and release
      the job in the print queue for printing
Notes:    this function is supported by Advanced NetWare 2.1+
    after this call, the specified LPT defaults to local printing
SeeAlso: AH=DFh/DL=01h,AH=DFh/DL=04h,AH=DFh/DL=06h,AH=DFh/DL=07h
--------N-21DF--DL06-------------------------
INT 21 - Novell NetWare - PRINT SERVICES - CANCEL SPECIFIC LPT CAPTURE
    AH = DFh
    DL = 06h
    DH = LPT port (00h-02h)
Return: AL = status
        00h successful
Desc:    this function ends the capture of the specified LPT, removes the job
      from the print queue, and deletes the capture file unless it is a
      permanent capture file
Notes:    this function is supported by Advanced NetWare 2.1+
    after this call, the specified LPT defaults to local printing
SeeAlso: AH=DFh/DL=02h,AH=DFh/DL=04h,AH=DFh/DL=05h,AH=DFh/DL=07h
--------N-21DF--DL07-------------------------
INT 21 - Novell NetWare - PRINT SERVICES - FLUSH SPECIFIC LPT CAPTURE
    AH = DFh
    DL = 07h
    DH = LPT port (00h-02h)
Return: AL = status
        00h successful
Desc:    this function closes the current capture file for the specified LPT
      and starts printing it if it is not a permanent capture file
Notes:    this function is supported by Advanced NetWare 2.1+
    if more data is sent to the LPT port after this call, a new capture
      file will be opeend
SeeAlso: AH=DFh/DL=03h,AH=DFh/DL=04h,AH=DFh/DL=05h,AH=DFh/DL=06h
--------T-21DF00DX534C-----------------------
INT 21 U - Software Carousel - INSTALLATION CHECK
    AX = DF00h
    DX = 534Ch ("SL")
    DI = 534Ch ("SL")
Return: AX = 00FFh if installed
        ???
Program: Software Carousel is a task switcher by SoftLogic Solutions, Inc.
--------T-21DF01-----------------------------
INT 21 - Software Carousel - SWITCH TO ANOTHER TASK
    AX = DF01h
    BL = task number (00h = next task)
Return: AL = status
        00h Carousel not running
        01h successful
        FFh unsucessful
        AH = error code (01h,02h) (see #1147)

(Table 1147)
Values for Software Carousel error code:
 00h    invalid subfunction in AL
 01h    invalid task number
 02h    tried to switch to task with no memory size
 03h    tried to kill program in partition with no program running
 04h    tried to change size of an active memory partition
 05h    invalid memory size
 06h    tried to send command to task with a pending previous command
--------T-21DF02-----------------------------
INT 21 - Software Carousel - KILL PROGRAM IN MEMORY PARTITION
    AX = DF02h
    BL = task number
Return: AL = status
        00h Carousel not running
        01h successful
        FFh unsucessful
        AH = error code (01h,03h) (see #1147)
--------T-21DF03-----------------------------
INT 21 - Software Carousel - GET PARTITION SIZE AND PROGRAM STATUS
    AX = DF03h
    BL = task number
Return: AL = status
        00h Carousel not running
        01h successful
        BL = partition state (00h no program running, 01h prog running)
        DX = partition size in KB
        FFh unsucessful
        AH = error code (01h) (see #1147)
SeeAlso: AX=DF05h
--------T-21DF04-----------------------------
INT 21 - Software Carousel - GET PARTITION NAME
    AX = DF04h
    BL = task number
Return: AL = status
        00h Carousel not running
        01h successful
        CX = length of name (00h if default partition name)
        ES:BX -> partition name (if CX nonzero)
        FFh unsucessful
        AH = error code (01h) (see #1147)
SeeAlso: AX=DF06h
--------T-21DF05-----------------------------
INT 21 - Software Carousel - CHANGE PARTITION SIZE
    AX = DF05h
    BL = task number
    DX = new size in KB
Return: AL = status
        00h Carousel not running
        01h successful
        FFh unsucessful
        AH = error code (01h,04h,05h) (see #1147)
    BX = minimum size allowed
    CX = maximum size available
SeeAlso: AX=DF03h
--------T-21DF06-----------------------------
INT 21 - Software Carousel - CHANGE PARTITION NAME
    AX = DF06h
    BL = task number
    CX = length of new name (00h to use default, max 18h)
    DS:SI -> new name
Return: AL = status
        00h Carousel not running
        01h successful
        FFh unsucessful
        AH = error code (01h) (see #1147)
SeeAlso: AX=DF04h
--------T-21DF07-----------------------------
INT 21 - Software Carousel - SEND COMMAND TO MEMORY SECTION
    AX = DF07h
    BL = task number
    CX = length of command (max 8 chars)
    DS:SI -> command line
Return: AL = status
        00h Carousel not running
        01h successful
        FFh unsucessful
        AH = error code (01h,06h) (see #1147)
Note:    the maximum length seems too small and may be a typo for 80 characters
--------T-21DF08-----------------------------
INT 21 - Software Carousel - SELECTIVELY ENABLE/DISABLE MENU AND SWITCHING
    AX = DF08h
    BL = new state of keyboard (00h disabled, 01h enabled)
Return: AL = status
        00h Carousel not running
        01h successful
Program: Software Carousel is a task switcher by SoftLogic Solutions, Inc.
Note:    when the keyboard is is disabled, the user may neither access the
      Carousel menu nor switch to another memory section
--------T-21DF09-----------------------------
INT 21 - Software Carousel - BOOT THE SYSTEM
    AX = DF09h
Return: AL = status
        00h Carousel not running
        FFh unsucessful
        AH = error code (01h,03h) (see #1147)
Note:    this function never returns if successful
--------T-21DF0A-----------------------------
INT 21 - Software Carousel - GET MEMORY SIZE/PARTITION NUMBER OF CURRENT TASK
    AX = DF0Ah
Return: AL = status
        00h Carousel not running
        01h successful
        BL = task number
        DX = memory size in KB
        FFh unsucessful
        AH = error code (01h,03h) (see #1147)
--------T-21DF0B-----------------------------
INT 21 - Software Carousel - SET TASK SWITCH CALLBACK
    AX = DF0Bh
    BH = interrupt number or 00h
    BL = function number to invoke on partition switch
    CL = function number to call when it is safe for resident programs
        to perform DOS calls
    DS:DX -> FAR function to call if BH=00h
Return: AL = status
        00h Carousel not running
        01h successful
        FFh unsucessful
        AH = error code (01h,03h) (see #1147)
Notes:    the specified interrupt or FAR function is called with AH set to the
      appropriate one of the values specified in BL and CL, and BL set to
      the new task number
    the function specified by CL will not be called until the notification
      is enabled with AX=DF0Ch
SeeAlso: AX=DF0Ch
--------T-21DF0C-----------------------------
INT 21 - Software Carousel - ENABLE DOS-CALL SAFETY NOTIFICATION
    AX = DF0Ch
Return: AL = status
        00h Carousel not running
        01h successful
Program: Software Carousel is a task switcher by SoftLogic Solutions, Inc.
SeeAlso: AX=DF0Bh
--------O-21E0-------------------------------
INT 21 - Digital Research DOS Plus - CALL BDOS
    AH = E0h
    CL = BDOS function number (see #3268 at INT E0"CP/M-86")
    other registers as appropriate for function
Return: as appropriate for function
SeeAlso: AX=4459h,INT E0"CP/M-86"
--------E-21E0-------------------------------
INT 21 - OS/286, OS/386 - INITIALIZE REAL PROCEDURE
    AH = E0h
    ???
Return: ???
SeeAlso: AH=E1h"OS/286"
--------T-21E0-------------------------------
INT 21 - DoubleDOS - MENU CONTROL
    AH = E0h
    AL = subfunction
        01h exchange tasks
        73h resume invisible job if suspended
        74h kill other job
        75h suspend invisible job
Note:    identical to AH=F0h
SeeAlso: AH=F0h"DoubleDOS"
--------v-21E0-------------------------------
INT 21 - VIRUS - "Jerusalem", "Armagedon" - INSTALLATION CHECK
    AH = E0h
Return: AX = 0300h if "Jerusalem" resident
    AX = DADAh if "Armagedon" resident
SeeAlso: AH=DEh"VIRUS",AX=DEDEh"VIRUS",AX=E00Fh
--------N-21E0-------------------------------
INT 21 - Novell NetWare, Alloy NTNX - PRINT SPOOLING
    AH = E0h
    DS:SI -> request buffer (see #1148)
    ES:DI -> reply buffer
Return: AL = status
Note:    this function was added in NetWare 4.0, but is no longer listed in
      current Novell documentation and may no longer be supported
SeeAlso: AH=E3h/SF=68h,AX=F211h/SF=06h,AX=F211h/SF=0Ah

Format of NetWare print spooling request buffer:
Offset    Size    Description    (Table 1148)
 00h    WORD    length of following data
 02h    BYTE    subfunction
        00h spool data to a capture file
        01h close and queue capture file
        02h set spool flags
        03h spool existing file
        04h get spool queue entry
        05h remove entry from spool queue
 03h    ???
SeeAlso: #1437
--------N-21E0--SF06-------------------------
INT 21 - Novell NetWare - PRINT SERVICES - GET PRINTER STATUS
    AH = E0h subfn 06h
    DS:SI -> request buffer (see #1149)
    ES:DI -> reply buffer (see #1150)
Return: AL = status
        00h successful
        FFh no such printer
Desc:    get current state of specified printer attached to the server
Note:    this function is supported by NetWare 4.0+, Advanced NetWare 1.0+, and
      Alloy NTNX

Format of NetWare "Get Printer Status" request buffer:
Offset    Size    Description    (Table 1149)
 00h    WORD    0002h (length of following data)
 02h    BYTE    06h (subfunction "Get Printer Status")
 03h    BYTE    printer number (00h-04h)
SeeAlso: #1150

Format of NetWare "Get Printer Status" reply buffer:
Offset    Size    Description    (Table 1150)
 00h    WORD    (call) 0004h (size of following results buffer)
 02h    BYTE    flag: 00h printer active, FFh printer halted
 03h    BYTE    flag: 00h printer online, 01h printer offline
 04h    BYTE    current form type
 05h    BYTE    target printer number (00h-04h)
        same as number in request buffer unless rerouted by server
          console
SeeAlso: #1149
--------N-21E0--SF09-------------------------
INT 21 - Novell NetWare - PRINT SERVICES - SPECIFY CAPTURE FILE
    AH = E0h subfn 09h
    DS:SI -> request buffer (see #1151)
    ES:DI -> reply buffer (see #1152)
Return: AL = status
        00h successful
        9Ch invalid path
Desc:    create a permanent capture file for the next print capture to be
      started
Notes:    this function is supported by NetWare 4.0+, Advanced NetWare 1.0+, and
      Alloy NTNX
    the caller must have read, write, and create rights for the directory
      containing the capture file

Format of NetWare "Specify Capture File" request buffer:
Offset    Size    Description    (Table 1151)
 00h    WORD    length of following data (max 102h)
 02h    BYTE    09h (subfunction "Specify Capture File")
 03h    BYTE    directory handle or 00h
 04h    BYTE    length of filename
 05h  N BYTEs    name of capture file
SeeAlso: #1152

Format of NetWare reply buffer:
Offset    Size    Description    (Table 1152)
 00h    WORD    (call) 0000h (no results returned)
SeeAlso: #1151
--------v-21E00F-----------------------------
INT 21 - VIRUS - "8-tunes" - INSTALLATION CHECK
    AX = E00Fh
Return: AX = 4C31h if resident
SeeAlso: AH=E0h"VIRUS",AH=E1h"VIRUS"
--------E-21E1-------------------------------
INT 21 - OS/286, OS/386 - ISSUE REAL PROCEDURE CALL
    AH = E1h
    ???
Return: ???
Note:    protected mode only???
SeeAlso: AH=E0h"OS/286",AH=E2h"OS/286",AH=E3h"OS/286",AX=250Eh,INT 31/AX=0301h
--------T-21E1-------------------------------
INT 21 - DoubleDOS - CLEAR KEYBOARD BUFFER FOR CURRENT JOB
    AH = E1h
SeeAlso: AH=E2h"DoubleDOS",AH=E3h"DoubleDOS",AH=E8h"DoubleDOS"
SeeAlso: AH=F1h"DoubleDOS"
--------v-21E1-------------------------------
INT 21 - VIRUS - "Mendoza", "Fu Manchu" - INSTALLATION CHECK
    AH = E1h
Return: AX = 0300h if "Mendoza" resident
    AX = 0400h if "Fu Manchu" resident
SeeAlso: AX=E00Fh,AH=E4h"VIRUS"
--------N-21E1--SF00-------------------------
INT 21 - Novell NetWare - MESSAGE SERVICES - SEND BROADCAST MESSAGE
    AH = E1h subfn 00h
    DS:SI -> request buffer (see #1153)
    ES:DI -> reply buffer (see #1154)
Return: AL = status
        00h successful
        FEh I/O error or out of dynamic workspace
Note:    this function is supported by NetWare 4.0+ and Advanced NetWare 1.0+
SeeAlso: AH=DEh"NetWare",AH=DEh/DL=04h,AH=E1h/SF=01h,AH=E1h/SF=04h
SeeAlso: AH=E1h/SF=09h

Format of NetWare "Send Broadcast Message" request buffer:
Offset    Size    Description    (Table 1153)
 00h    WORD    length of following data (max 9Eh)
 02h    BYTE    00h (subfunction "Send Broadcast Message")
 03h    BYTE    number of connections (01h-64h)
 04h  N BYTEs    list of connections to receive broadcast message
    BYTE    length of message (01h-37h)
      N BYTEs    broadcast message (no control characters or characters > 7Eh)
SeeAlso: #1154

Format of NetWare "Send Broadcast Message" reply buffer:
Offset    Size    Description    (Table 1154)
 00h    WORD    (call) size of following results buffer (max 65h)
 02h    BYTE    number of connections
 03h  N BYTEs    list of per-connection results
        00h successful
        FCh message rejected due to lack of buffer space
        FDh invalid connection number
        FFh blocked (see also AH=E1h/SF=02h)
SeeAlso: #1153
--------N-21E1--SF01-------------------------
INT 21 - Novell NetWare - MESSAGE SERVICES - GET BROADCAST MESSAGE (OLD)
    AH = E1h subfn 01h
    DS:SI -> request buffer (see #1155)
    ES:DI -> reply buffer (see #1156)
Return: AL = status
        00h successful
        FCh full message queue
        FEh out of dynamic workspace
Note:    this function is supported by NetWare 4.0+ and Advanced NetWare 1.0+
SeeAlso: AH=DEh/DL=04h,AH=E1h/SF=00h,AH=E1h/SF=05h,AH=E1h/SF=09h
SeeAlso: AX=F215h/SF=01h,AX=F215h/SF=0Bh

Format of NetWare "Get Broadcast Message" request buffer:
Offset    Size    Description    (Table 1155)
 00h    WORD    0001h (length of following data)
 02h    BYTE    01h (subfunction "Get Broadcast Message")
SeeAlso: #1156,#1445

Format of NetWare "Get Broadcast Message" reply buffer:
Offset    Size    Description    (Table 1156)
 00h    WORD    (call) size of following results buffer (max 38h)
 02h    BYTE    length of message (00h-37h)
        00h if no broadcast messages pending
 03h  N BYTEs    message (no control characters or characters > 7Eh)
SeeAlso: #1155,#1443,#1446
--------N-21E1--SF02-------------------------
INT 21 - Novell NetWare - MESSAGE SERVICES - DISABLE BROADCAST MESSAGES
    AH = E1h subfn 02h
    DS:SI -> request buffer (see #1158)
    ES:DI -> reply buffer (see #1159)
Return: AL = error code
Note:    these functions are supported by NetWare 4.0+ but are not listed in
      _NetWare_System_Calls--DOS_; they may be obsolete
SeeAlso: AH=E1h/SF=00h,AH=E1h/SF=03h,AH=E1h/SF=04h,AH=E1h/SF=09h
SeeAlso: AX=F215h/SF=02h

Format of NetWare "Disable Broadcasts" request packet:
Offset    Size    Description    (Table 1157)
 00h    WORD    0001h (length of following data)
 02h    BYTE    02h (subfunction "Enable Broadcast Messages")
SeeAlso: #1158,#1159
--------N-21E1--SF03-------------------------
INT 21 - Novell NetWare - MESSAGE SERVICES - ENABLE BROADCAST MESSAGES
    AH = E1h subfn 03h
    DS:SI -> request buffer (see #1158)
    ES:DI -> reply buffer (see #1159)
Return: AL = error code
Note:    these functions are supported by NetWare 4.0+ but are not listed in
      _NetWare_System_Calls--DOS_; they may be obsolete
SeeAlso: AH=E1h/SF=00h,AH=E1h/SF=02h,AH=E1h/SF=04h,AH=E1h/SF=09h
SeeAlso: AX=F215h/SF=03h

Format of NetWare "Enable Broadcast Messages" request buffer:
Offset    Size    Description    (Table 1158)
 00h    WORD    0001h (length of following data)
 02h    BYTE    03h (subfunction "Enable Broadcast Messages")
SeeAlso: #1159,#1157

Format of NetWare "Enable/Disable Broadcast Messages" reply buffer:
Offset    Size    Description    (Table 1159)
 00h    WORD    (call) 0000h (no data returned)
SeeAlso: #1158,#1157
--------N-21E1--SF04-------------------------
INT 21 O - Novell NetWare - MESSAGE SERVICES - SEND PERSONAL MESSAGE
    AH = E1h subfn 04h
    DS:SI -> request buffer (see #1160)
    ES:DI -> reply buffer (see #1161)
Return: AL = status
        00h successful
        FEh I/O error or out of dynamic workspace
Notes:    this function is supported by NetWare 4.0+ and Advanced NetWare 1.0-2.x
    message pipes use CPU time on the file server; IPX, SPX, or NetBIOS
      connections should be used for peer-to-peer communications as these
      protocols do not use file server time
SeeAlso: AH=E1h/SF=00h,AH=E1h/SF=05h,AH=E1h/SF=06h,AH=E1h/SF=08h

Format of NetWare "Send Personal Message" request buffer:
Offset    Size    Description    (Table 1160)
 00h    WORD    length of following data (max E5h)
 02h    BYTE    04h (subfunction "Send Personal Message")
 03h    BYTE    number of connections (01h-64h)
 04h  N BYTEs    list of connections to receive broadcast message
    BYTE    length of message (01h-7Eh)
      N BYTEs    message (no control characters or characters > 7Eh)
SeeAlso: #1161

Format of NetWare "Send Personal Message" reply buffer:
Offset    Size    Description    (Table 1161)
 00h    WORD    (call) size of following results buffer (max 65h)
 02h    BYTE    number of connections
 03h  N BYTEs    list of per-connection results
        00h successful
        FCh message rejected because queue is full (contains 6 msgs)
        FDh incomplete pipe
        FFh failed
SeeAlso: #1160
--------N-21E1--SF05-------------------------
INT 21 O - Novell NetWare - MESSAGE SERVICES - GET PERSONAL MESSAGE
    AH = E1h subfn 05h
    DS:SI -> request buffer (see #1162)
    ES:DI -> reply buffer (see #1163)
Return: AL = status
        00h successful
        FEh out of dynamic workspace
Desc:    return the oldest message in the default file server's message queue
      for the calling workstation
Note:    this function is supported by NetWare 4.0+ and Advanced NetWare 1.0-2.x
SeeAlso: AH=E1h/SF=01h,AH=E1h/SF=04h,AH=E1h/SF=06h,AH=E1h/SF=08h

Format of NetWare "Get Personal Message" request buffer:
Offset    Size    Description    (Table 1162)
 00h    WORD    0001h (length of following data)
 02h    BYTE    05h (subfunction "Get Personal Message")
SeeAlso: #1163

Format of NetWare "Get Personal Message" reply buffer:
Offset    Size    Description    (Table 1163)
 00h    WORD    (call) size of following results buffer (max 80h)
 02h    BYTE    connection number of sending station
 03h    BYTE    length of message (00h-7Eh)
        00h if no personal messages pending
 04h  N BYTEs    message (no control characters or characters > 7Eh)
SeeAlso: #1162
--------N-21E1--SF06-------------------------
INT 21 O - Novell NetWare - MESSAGE SERVICES - OPEN MESSAGE PIPE
    AH = E1h subfn 06h
    DS:SI -> request buffer (see #1164)
    ES:DI -> reply buffer (see #1165)
Return: AL = status
        00h successful
        FEh out of dynamic workspace
Note:    this function is supported by NetWare 4.0+ and Advanced NetWare 1.0-2.x
SeeAlso: AH=E1h/SF=04h,AH=E1h/SF=07h,AH=E1h/SF=08h

Format of NetWare "Open Message Pipe" request buffer:
Offset    Size    Description    (Table 1164)
 00h    WORD    length of following data (max 66h)
 02h    BYTE    06h (subfunction "Open Message Pipe")
 03h    BYTE    number of pipes to open (01h-64h)
 04h  N BYTEs    list of connection numbers
SeeAlso: #1165,#1166,#1169

Format of NetWare "Open Message Pipe" reply buffer:
Offset    Size    Description    (Table 1165)
 00h    WORD    (call) size of following results buffer (max 65h)
 02h    BYTE    number of connections
 03h  N BYTEs    list of results
        00h successful
        FEh incomplete (target half not yet created)
        FFh failed
SeeAlso: #1164,#1167,#1170
--------N-21E1--SF07-------------------------
INT 21 O - Novell NetWare - MESSAGE SERVICES - CLOSE MESSAGE PIPE
    AH = E1h subfn 07h
    DS:SI -> request buffer (see #1166)
    ES:DI -> reply buffer (see #1167)
Return: AL = status
        00h successful
        FCh full message queue
        FEh out of dynamic workspace
Note:    this function is supported by NetWare 4.0+ and Advanced NetWare 1.0-2.x
SeeAlso: AH=E1h/SF=05h,AH=E1h/SF=06h,AH=E1h/SF=08h

Format of NetWare "Close Mesage Pipe" request buffer:
Offset    Size    Description    (Table 1166)
 00h    WORD    length of following data (max 66h)
 02h    BYTE    07h (subfunction "Close Message Pipe")
 03h    BYTE    number of pipes to close (01h-64h)
 04h  N BYTEs    list of connection numbers
SeeAlso: #1164,#1167

Format of NetWare "Close Message Pipe" reply buffer:
Offset    Size    Description    (Table 1167)
 00h    WORD    (call) size of following results buffer (max 65h)
 02h    BYTE    number of connections
 03h  N BYTEs    list of results
        00h successful
        FDh failed
        FFh no such pipe
SeeAlso: #1165,#1166
--------N-21E1--SF08-------------------------
INT 21 O - Novell NetWare - MESSAGE SERVICES - CHECK PIPE STATUS
    AH = E1h subfn 08h
    DS:SI -> request buffer (see #1169)
    ES:DI -> reply buffer (see #1170)
Return: AL = status (see #1168)
Note:    this function is supported by NetWare 4.0+ and Advanced NetWare 1.0-2.x
SeeAlso: AH=E1h/SF=05h,AH=E1h/SF=06h,AH=E1h/SF=07h,AX=F215h/SF=08h

(Table 1168)
Values for NetWare function status:
 00h    successful
 FCh    full message queue
 FEh    out of dynamic workspace
SeeAlso: #1173

Format of NetWare "Check Pipe Status" request buffer:
Offset    Size    Description    (Table 1169)
 00h    WORD    length of following data (max 66h)
 02h    BYTE    08h (subfunction "Check Pipe Status")
 03h    BYTE    number of pipes to monitor (01h-64h)
 04h  N BYTEs    list of connection numbers
SeeAlso: #1164,#1170

Format of NetWare "Check Pipe Status" reply buffer:
Offset    Size    Description    (Table 1170)
 00h    WORD    (call) size of following results buffer (max 65h)
 02h    BYTE    number of connections
 03h  N BYTEs    list of pipe statuses
        00h open
        FEh incomplete
        FFh closed
SeeAlso: #1165,#1169,#1444
--------N-21E1--SF09-------------------------
INT 21 - Novell NetWare - MESSAGE SERVICES - BROADCAST TO CONSOLE
    AH = E1h subfn 09h
    DS:SI -> request buffer (see #1171)
    ES:DI -> reply buffer (see #1172)
Return: AL = status (see #1168)
Desc:    send a one-line message to the system console on the default file
      server
Note:    this function is supported by NetWare 4.0+ and Advanced NetWare 1.0+
SeeAlso: AH=DEh/DL=04h,AH=E1h/SF=00h,AH=E1h/SF=01h,AH=E3h/SF=D1h
SeeAlso: AX=F215h/SF=09h

Format of NetWare "Broadcast to Console" request buffer:
Offset    Size    Description    (Table 1171)
 00h    WORD    length of following data (max 3Eh)
 02h    BYTE    09h (subfunction "Broadcast to Console")
 03h    BYTE    length of message (01h-3Ch)
 04h  N BYTEs    message (no control characters or characters > 7Eh)
SeeAlso: #1172

Format of NetWare reply buffer:
Offset    Size    Description    (Table 1172)
 00h    WORD    (call) 0000h (no results returned)
SeeAlso: #1171
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