Libris Britannia 4/science library(b).zip/science library(b)/INFO/INTER39B.ZIP/INTERRUP.F

Text File | 1994-02-06 | 323KB | 8,441 lines

Interrupt List, part 6 of 10
This compilation is Copyright (c) 1989,1990,1991,1992,1993,1994 Ralf Brown
--------D-22---------------------------------
INT 22 - DOS 1+ - PROGRAM TERMINATION ADDRESS
Desc:    this vector specifies the address of the routine which is to be given
      control after a program is terminated; it should never be called
      directly, since it does not point at an interrupt handler
Notes:    this vector is restored from the DWORD at offset 0Ah in the PSP during
      termination, and then a FAR JMP is performed to the address in INT 22
    normally points at the instruction immediately following INT 21/AH=4Bh
      call which loaded the current program
SeeAlso: INT 20,INT 21/AH=00h,INT 21/AH=31h,INT 21/AH=4Ch
--------G-22---------------------------------
INT 22 - COMTROL HOSTESS i/ISA DEBUGGER - CHANGE FIRMWARE DEBUGGING PORT
    AL = new firmware debugging port
Return: ???
SeeAlso: INT 21"COMTROL",INT 23"COMTROL"
--------D-23---------------------------------
INT 23 - DOS 1+ - CONTROL-C/CONTROL-BREAK HANDLER
---DOS 1.x---
Return: AH = 00h abort program
    if all registers preserved, restart DOS call
---DOS 2+---
    CF clear
Return: all registers preserved
    return via RETF or RETF 2 with CF set
        DOS will abort program with errorlevel 0
    else (RETF/RETF 2 with CF clear or IRET)
        interrupted DOS call is restarted
Notes:    this interrupt is invoked whenever DOS detects a ^C or ^Break; it
      should never be called directly
    MS-DOS 1.25 also invokes INT 23 on a divide overflow (INT 00)
    DOS remembers the stack pointer before calling INT 23, and if it is
      not the same on return, pops and discards the top word; this is what
      permits a return with RETF as well as IRET or RETF 2
    any DOS call may safely be made within the INT 23 handler, although
      the handler must check for a recursive invocation if it does
      call DOS
SeeAlso: INT 1B
--------G-23---------------------------------
INT 23 - COMTROL HOSTESS i/ISA DEBUGGER - GET CONFIGURATION INFORMATION
    AL = query type
        00h get old config map
        Return: AX = old config map
        01h get dual-ported RAM map
        Return: BX:AX = dual-ported RAM map
        02h get SCC port map
        Return: BX:AX = SCC port map
SeeAlso: INT 22"COMTROL",INT 26"COMTROL"
--------D-24---------------------------------
INT 24 - DOS 1+ - CRITICAL ERROR HANDLER
Note:    invoked when a critical (usually hardware) error is encountered; should
      never be called directly
SeeAlso: INT 21/AH=95h

Critical error handler is invoked with:
    AH = type and processing flags
        bit 7 clear = disk I/O error
          set    = -- if block device, bad FAT image in memory
              -- if char device, error code in DI
        bit 6  unused
        bit 5 = 1 if Ignore allowed, 0 if not (DOS 3+)
        bit 4 = 1 if Retry allowed, 0 if not (DOS 3+)
        bit 3 = 1 if Fail allowed, 0 if not (DOS 3+)
        bit 2 \ disk area of error    00 = DOS area  01 = FAT
        bit 1 /            10 = root dir  11 = data area
        bit 0 = 1 if write, 0 if read
    AL = drive number if AH bit 7 clear
    BP:SI -> device driver header (BP:[SI+4] bit 15 set if char device)
    DI low byte contains error code if AH bit 7 set
       00h write-protection violation attempted
       01h unknown unit for driver
       02h drive not ready
       03h unknown command given to driver
       04h data error (bad CRC)
       05h bad device driver request structure length
       06h seek error
       07h unknown media type
       08h sector not found
       09h printer out of paper
       0Ah write fault
       0Bh read fault
       0Ch general failure
       0Dh (DOS 3+) sharing violation
       0Eh (DOS 3+) lock violation
       0Fh invalid disk change
       10h (DOS 3+) FCB unavailable
       11h (DOS 3+) sharing buffer overflow
       12h (DOS 4+) code page mismatch
       13h (DOS 4+) out of input
       14h (DOS 4+) insufficient disk space
    STACK:    DWORD    return address for INT 24 call
        WORD    flags pushed by INT 24
        WORD    original AX on entry to INT 21
        WORD    BX
        WORD    CX
        WORD    DX
        WORD    SI
        WORD    DI
        WORD    BP
        WORD    DS
        WORD    ES
        DWORD    return address for INT 21 call
        WORD    flags pushed by INT 21
Handler must return:
    AL = action code
        00h ignore error and continue processing request
        01h retry operation
        02h terminate program through the equivalent of INT 21/AH=4Ch
            (INT 20h for DOS 1.x)
        03h fail system call in progress
    SS,SP,DS,ES,BX,CX,DX preserved
Notes:    the only DOS calls the handler may make are INT 21/AH=01h-0Ch,30h,59h
    if the handler returns to the application by popping the stack, DOS
      will be in an unstable state until the first call with AH > 0Ch
    for DOS 3.1+, IGNORE (AL=00h) is turned into FAIL (AL=03h) on network
      critical errors
    if IGNORE specified but not allowed, it is turned into FAIL
    if RETRY specified but not allowed, it is turned into FAIL
    if FAIL specified but not allowed, it is turned into ABORT
    (DOS 3+) if a critical error occurs inside the critical error handler,
      the DOS call is automatically failed
--------D-25---------------------------------
INT 25 - DOS 1+ - ABSOLUTE DISK READ (except partitions > 32M)
    AL = drive number (00h = A:, 01h = B:, etc)
    CX = number of sectors to read
    DX = starting logical sector number (0000h - highest sector on drive)
    DS:BX -> buffer for data
Return: CF clear if successful
    CF set on error
        AH = status
         80h device failed to respond (timeout)
         40h seek operation failed
         20h controller failed
         10h data error (bad CRC)
         08h DMA failure
         04h requested sector not found
         03h write-protected disk (INT 26 only)
         02h bad address mark
         01h bad command
        AL = error code (same as passed to INT 24 in DI)
        AX = 0207h if more than 64K sectors on drive -- use new-style call
    may destroy all other registers except segment registers
Notes:    original flags are left on stack, and must be popped by caller
    this call bypasses the DOS filesystem
    examination of CPWIN386.CPL indicates that if this call fails with
      error 0408h on an old-style (<32M) call, one should retry the
      call with the high bit of the drive number in AL set
BUGS:    DOS 3.1 through 3.3 set the word at ES:[BP+1Eh] to FFFFh if AL is an
      invalid drive number
    DR-DOS 3.41 will return with a jump instead of RETF, leaving the
      wrong number of bytes on the stack; use the huge-partition version
      (INT 25/CX=FFFFh) for all partition sizes under DR-DOS 3.41
SeeAlso: INT 13/AH=02h,INT 25/CX=FFFFh,INT 26
--------D-25----CXFFFF-----------------------
INT 25 - DOS 3.31+ - ABSOLUTE DISK READ (>32M hard-disk partition)
    CX = FFFFh
    AL = drive number (0=A, 1=B, etc)
    DS:BX -> disk read packet (see below)
Return: same as above
Notes:    partition is potentially >32M (and requires this form of the call) if
      bit 1 of device attribute word in device driver is set
    original flags are left on stack, and must be removed by caller
    this call bypasses the DOS filesystem
SeeAlso: INT 13/AH=02h,INT 25,INT 26/CX=FFFFh

Format of disk read packet:
Offset    Size    Description
 00h    DWORD    sector number
 04h    WORD    number of sectors to read
 06h    DWORD    transfer address
--------d-25CDCD-----------------------------
INT 25 - Stacker - GET DEVICE DRIVER ADDRESS
    AX = CDCDh
    DS:BX -> buffer for address (see below)
    CX = 0001h
    DX = 0000h
Return: AX = CDCDh if Stacker installed
        DS:BX buffer filled

Format of driver address buffer:
Offset    Size    Description
 00h    WORD    signature CDCDh
 02h    WORD    ??? 0001h
 04h    DWORD    pointer to start of Stacker device driver

Format of device driver:
Offset    Size    Description
 00h    WORD    signature A55Ah
 02h    WORD    Stacker version * 64h
 04h    WORD    offset of volume-specific information offset table
        (list of WORDs, one per drive, containing offsets to various
        information)
 06h 56 BYTEs    n/a
 3Eh    BYTE    volume number, set after INT 21/AX=4404h
        (use to index into volume-specific info offset table)
 3Fh 19 BYTEs    n/a
 52h  4 BYTEs    ASCII string "SWAP"
 56h 26 BYTEs    drive mapping table (one byte for each drive A: through Z:)

Format of Stacker boot record:
Offset    Size    Description
1F0h  8 BYTEs    Stacker signature (first byte is CDh)
1F8h    DWORD    pointer to start of Stacker device driver
1FCh    WORD    Stacker volume number
1FEh    WORD    ???
--------c-25--FFSI4358-----------------------
INT 25 - PC-CACHE.SYS - INSTALLATION CHECK
    AL = FFh
    SI = 4358h
Return: SI = 6378h if installed
        CX = segment of device driver PC-CACHE.SYS
        DX = version (major in DH, minor in DL)
Program: PC-CACHE.SYS is a small device driver used by PC-Cache v5.x to obtain
      access to certain disk drivers for devices such as Bernoulli drives
SeeAlso: INT 13/AH=A0h
--------D-26---------------------------------
INT 26 - DOS 1+ - ABSOLUTE DISK WRITE (except partitions > 32M)
    AL = drive number (00h = A:, 01h = B:, etc)
    CX = number of sectors to write
    DX = starting logical sector number (0000h - highest sector on drive)
    DS:BX -> data to write
Return: CF clear if successful
    CF set on error
        AH = status
         80h device failed to respond (timeout)
         40h seek operation failed
         20h controller failed
         10h data error (bad CRC)
         08h DMA failure
         04h requested sector not found
         03h write-protected disk (INT 26 only)
         02h bad address mark
         01h bad command
        AL = error code (same as passed to INT 24 in DI)
        AX = 0207h if more than 64K sectors on drive -- use new-style call
    may destroy all other registers except segment registers
Notes:    original flags are left on stack, and must be popped by caller
    this call bypasses the DOS filesystem, though DOS 5+ invalidates any
      disk buffers referencing sectors which are written with this call
    examination of CPWIN386.CPL indicates that if this call fails with
      error 0408h on an old-style (<32M) call, one should retry the
      call with the high bit of the drive number in AL set
BUGS:    DOS 3.1 through 3.3 set the word at ES:[BP+1Eh] to FFFFh if AL is an
      invalid drive number
    DR-DOS 3.41 will return with a jump instead of RETF, leaving the
      wrong number of bytes on the stack; use the huge-partition version
      (INT 26/CX=FFFFh) for all partition sizes under DR-DOS 3.41
SeeAlso: INT 13/AH=03h,INT 25,INT 26/CX=FFFFh
--------D-26----CXFFFF-----------------------
INT 26 - DOS 3.31+ - ABSOLUTE DISK WRITE (>32M hard-disk partition)
    CX = FFFFh
    AL = drive number (0=A, 1=B, etc)
    DS:BX -> disk write packet (see below)
Return: same as above
Notes:    partition is potentially >32M (and requires this form of the call) if
      bit 1 of device attribute word in device driver is set
    original flags are left on stack, and must be removed by caller
    this call bypasses the DOS filesystem, though DOS 5+ invalidates any
      disk buffers referencing sectors which are written with this call
SeeAlso: INT 13/AH=03h,INT 25/CX=FFFFh,INT 26

Format of disk write packet:
Offset    Size    Description
 00h    DWORD    sector number
 04h    WORD    number of sectors to read
 06h    DWORD    transfer address
--------G-26---------------------------------
INT 26 - COMTROL HOSTESS i/ISA DEBUGGER - ENTER/EXIT EXTENDED ADDRESSING MODE
    ???
Return: ???
SeeAlso: INT 23"COMTROL",INT 27"COMTROL"
--------D-27---------------------------------
INT 27 - DOS 1+ - TERMINATE AND STAY RESIDENT
    DX = number of bytes to keep resident (max FFF0h)
    CS = segment of PSP
Return: never
Notes:    this is an obsolete call
    INT 22, INT 23, and INT 24 are restored from the PSP
    does not close any open files
    the minimum number of bytes which will remain resident is 110h for
      DOS 2.x and 60h for DOS 3+; there is no minimum for DOS 1.x, which
      implements this service in COMMAND.COM rather than the DOS kernel
SeeAlso: INT 21/AH=31h
--------G-27---------------------------------
INT 27 - COMTROL HOSTESS i/ISA DEBUGGER - INVOKE REMOTE TURBO DEBUGGER KERNEL
    ???
Return: ???
Desc:    invoke a copy of the remote Turbo Debugger kernel on the Hostess i
      controller
SeeAlso: INT 20"COMTROL",INT 26"COMTROL"
--------D-28---------------------------------
INT 28 C - DOS 2+ - DOS IDLE INTERRUPT
    SS:SP = top of MS-DOS stack for I/O functions
Return: all registers preserved
Desc:    This interrupt is invoked each time one of the DOS character input
      functions loops while waiting for input.  Since a DOS call is in
      progress even though DOS is actually idle during such input waits,
      hooking this function is necessary to allow a TSR to perform DOS
      calls while the foreground program is waiting for user input.     The
      INT 28h handler may invoke any INT 21h function except functions
      00h through 0Ch.
Notes:    under DOS 2.x, the critical error flag (the byte immediately after the
      InDOS flag) must be set in order to call DOS functions 50h/51h from
      the INT 28h handler without destroying the DOS stacks.
    calls to INT 21/AH=3Fh,40h from within an INT 28 handler may not use a
      handle which refers to CON
    at the time of the call, the InDOS flag (see INT 21/AH=34h) is normally
      set to 01h; if larger, DOS is truly busy and should not be reentered
    the default handler is an IRET instruction
    supported in OS/2 compatibility box
    the _MS-DOS_Programmer's_Reference_ for DOS 5.0 incorrectly documents
      this interrupt as superseded
SeeAlso: INT 21/AH=34h,INT 2A/AH=84h,INT 2F/AX=1680h
--------D-29---------------------------------
INT 29 C - DOS 2+ - FAST CONSOLE OUTPUT
    AL = character to display
Return: nothing
Notes:    automatically called when writing to a device with bit 4 of its device
      driver header set (see also INT 21/AH=52h)
    COMMAND.COM v3.2 and v3.3 compare the INT 29 vector against the INT 20
      vector and assume that ANSI.SYS is installed if the segment is larger
    the default handler under DOS 2.x and 3.x simply calls INT 10/AH=0Eh
    the default handler under DESQview 2.2 understands the <Esc>[2J
      screen-clearing sequence, calls INT 10/AH=0Eh for all others
SeeAlso: INT 21/AH=52h,INT 2F/AX=0802h,INT 79
--------N-2A00-------------------------------
INT 2A - NETWORK (Microsoft, LANtastic) - INSTALLATION CHECK
    AH = 00h
Return: AH <> 00h if installed
    CF set if NetWare v2.15 NetBIOS emulator installed
Note:    also supported by Lantastic, NetWare, 10NET, etc.
SeeAlso: INT 5C
--------N-2A0000-----------------------------
INT 2A - AT&T Starlan Extended NetBIOS (var length names) - INSTALLATION CHECK
    AX = 0000h
Return: AH = DDh
SeeAlso: INT 5B
--------N-2A01-------------------------------
INT 2A - NETWORK (Microsoft,LANtastic) - EXECUTE NETBIOS REQUEST,NO ERROR RETRY
    AH = 01h
    ES:BX -> NCB (see INT 5C)
Return: AL = NetBIOS error code
    AH = 00h if no error
       = 01h on error
SeeAlso: AH=04h,AX=0500h,INT 5B,INT 5C"NetBIOS"
--------N-2A02-------------------------------
INT 2A - NETWORK (Microsoft) - SET NET PRINTER MODE
    AH = 02h
    ???
Return: ???
--------N-2A0300-----------------------------
INT 2A - NETWORK (Microsoft,LANtastic) - CHECK DIRECT I/O
    AX = 0300h
    DS:SI -> ASCIZ device name (may be full path or only drive specifier--
        must include the colon)
Return: CF clear if direct physical addressing (INT 13,INT 25) permissible
    CF set if access via files only
Notes:    do not use direct disk accesses if this function returns CF set or the
      device is redirected (INT 21/AX=5F02h)
    may take some time to execute
    this function is called by the DOS kernel on INT 25 and INT 26
    also supported by Lantastic, NetWare, 10NET, etc.
SeeAlso: INT 13,INT 25,INT 26,INT 21/AX=5F02h
--------N-2A04-------------------------------
INT 2A - NETWORK (Microsoft,LANtastic) - EXECUTE NetBIOS REQUEST
    AH = 04h
    AL = error retry
        00h automatically retry request on errors 09h, 12h, and 21h
        01h no retry
        02h ???
    ES:BX -> Network Control Block (see INT 5C"NetBIOS")
Return: AX = 0000h if successful
    AH = 01h on error
        AL = error code
Notes:    invokes either INT 5B or INT 5C as appropriate
    also supported by Lantastic, NetWare, 10NET, etc.
    NetWare 2.15 NetBIOS emulator returns CF clear if successful, CF set
      on error
SeeAlso: AH=01h,AX=0500h,INT 5B,INT 5C"NetBIOS"
--------N-2A0500-----------------------------
INT 2A - NETWORK (Microsoft,LANtastic) - GET NETWORK RESOURCE AVAILABILITY
    AX = 0500h
Return: AX reserved
    BX = number of network names available
    CX = number of network control blocks available
    DX = number of network sessions available
Note:    also supported by Lantastic, NetWare, 10NET, etc.
SeeAlso: AH=01h,AH=04h,INT 5C"NetBIOS"
--------N-2A06-------------------------------
INT 2A - NETBIOS, LANtastic - NETWORK PRINT-STREAM CONTROL
    AH = 06h
    AL = 01h set concatenation mode (all printer output put in one job)
         02h set truncation mode (default)
         printer open/close starts new print job
         03h flush printer output and start new print job
Return: CF set on error
        AX = error code
    CF clear if successful
Notes:    subfunction 03h is equivalent to Ctrl/Alt/keypad-*
    also supported by LANtastic, NetWare, 10NET, etc.
    LANtastic v4.x no longer supports this call
SeeAlso: INT 21/AX=5D08h,INT 21/AX=5D09h,INT 2F/AX=1125h
--------N-2A07-------------------------------
INT 2A U - PC Network v1.00 - RECEIVER.COM - ???
    AH = 07h
    ???
Return: ???
Program: PC Network is an early networking package which was renamed the
      IBM PC Local Area Network Program (PC LAN Program) as of v1.10
SeeAlso: AH=86h
--------N-2A2001-----------------------------
INT 2A - MS Networks or NETBIOS - ???
    AX = 2001h
    ???
Return: ???
Note:    intercepted by DESQview 2.x
--------N-2A2002-----------------------------
INT 2A - NETWORK - ???
    AX = 2002h
    ???
Return: ???
Note:    called by MS-DOS 3.30-6.00 APPEND
--------N-2A2003-----------------------------
INT 2A - NETWORK - ???
    AX = 2003h
    ???
Return: ???
Note:    called by MS-DOS 3.30-6.00 APPEND
--------N-2A7802-----------------------------
INT 2A - NETWORK - PC LAN PROG v1.31+ - GET LOGGED ON USER NAME
    AX = 7802h
    ES:DI -> 8-byte buffer to be filled
Return: AL = 00h if no user logged on to Extended Services
    AL <> 00h if user logged on to Extended Services
        buffer at ES:DI filled with name, padded to 8 chars with blanks.
--------D-2A80-------------------------------
INT 2A CU - NETWORK - BEGIN DOS CRITICAL SECTION
    AH = 80h
    AL = critical section number (00h-0Fh)
        01h DOS kernel, SHARE.EXE, DOSMGR
        apparently for maintaining the integrity of DOS/SHARE/NET
          data structures
        02h DOS kernel, DOSMGR
        ensures that no multitasking occurs while DOS is calling an
          installable device driver
        05h network redirector
        06h DOS 4.x only IFSFUNC
        08h ASSIGN.COM
        0Ah MSCDEX
        0Fh IBM PC LAN server (while intercepting INT 10/AH=06h,07h,0Eh)
Notes:    normally hooked to avoid interrupting a critical section, rather than
      called
    the handler should ensure that none of the critical sections are
      reentered, usually by suspending a task which attempts to reenter
      an active critical section
    the DOS kernel does not invoke critical sections 01h and 02h unless it
      is patched.  DOS 3.1+ contains a zero-terminated list of words
      beginning at offset -11 from the Swappable Data Area
      (see INT 21/AX=5D06h); each word contains the offset within the
      DOS data segment of a byte which must be changed from C3h (RET)
      to 50h (POP AX) under DOS 3.x or from 00h to a nonzero value under
      DOS 4+ to enable use of critical sections.  For DOS 4+, all words in
      this list point at the byte at offset 0D0Ch.
SeeAlso: AH=81h,AH=82h,AX=8700h,INT 21/AX=5D06h,INT 21/AX=5D0Bh
--------D-2A81-------------------------------
INT 2A CU - NETWORK - END DOS CRITICAL SECTION
    AH = 81h
    AL = critical section number (00h-0Fh) (see AH=80h)
Notes:    normally hooked rather than called
    the handler should reawaken any tasks which were suspended due to an
      attempt to enter the specified critical section
SeeAlso: AH=80h,AH=82h,AX=8700h
--------D-2A82-------------------------------
INT 2A CU - NETWORK - END DOS CRITICAL SECTIONS 0 THROUGH 7
    AH = 82h
Notes:    called by the INT 21h function dispatcher for function 0 and functions
      greater than 0Ch except 59h, and on process termination
    the handler should reawaken any tasks which were suspended due to an
      attempt to enter one of the critical sections 0 through 7
SeeAlso: AH=81h
--------N-2A84-------------------------------
INT 2A CU - NETWORK - KEYBOARD BUSY LOOP
    AH = 84h
Note:    similar to DOS's INT 28h, called from inside the DOS keyboard input
      loop (i.e. INT 21/AH=07h or INT 21/AH=08h) to allow the network
      software to process requests
SeeAlso: INT 28
--------N-2A86-------------------------------
INT 2A U - PC Network v1.00 - RECEIVER.COM - ???
    AH = 86h
    ???
Return: ???
SeeAlso: AH=07h,AH=C4h
--------P-2A8700-----------------------------
INT 2A CU - PRINT - BEGIN BACKGROUND PRINTING
    AX = 8700h
    CF clear
Return: CF clear if OK to print in background now
    CF set if background printing not allowed at this time
Desc:    used to inform interested programs that PRINT is about to start its
      background processing, and allow those programs to postpone the
      processing if necessary
Notes:    when PRINT gains control and wants to begin printing, it calls this
      function.  If CF is clear on return, PRINT begins its background
      processing, and calls AX=8701h when it is done.  If CF is set on
      return, PRINT will relinquish control immediately, and will not
      call AX=8701h
    PCVENUS (an early network shell by IBM and CMU) hooks this call to
      prevent background printing while its own code is active
SeeAlso: AH=80h,AH=81h,AX=8701h
--------P-2A8701-----------------------------
INT 2A CU - PRINT - END BACKGROUND PRINTING
    AX = 8701h
Desc:    used to inform interested programs that PRINT has completed its
      background processing
Note:    called by PRINT after it has performed some background printing; not
      called if AX=8700h returned with CF set.
SeeAlso: AX=8700h
--------N-2A89-------------------------------
INT 2A U - PC Network v1.00 - RECEIVER.COM - ???
    AH = 89h
    AL = ???  (ASSIGN uses 08h)
    ???
Return: ???
--------I-2A90-------------------------------
INT 2A U - IBM PC 3270 EMULATION PROGRAM - ???
    AH = 90h
    ???
Return: ???
Note:    the LANtastic redirector and SERVER.EXE use this function with AL=01h,
      03h-07h,0Ch-11h
--------N-2AC2-------------------------------
INT 2A U - Network - ???
    AH = C2h
    AL = subfunction
        07h ???
        08h ???
    BX = 0001h
    ???
Return: ???
Note:    this function is called by the DOS 3.30-6.00 APPEND
--------N-2AC4-------------------------------
INT 2A U - PC Network v1.00 - RECEIVER.COM - ???
    AH = C4h
    AL = subfunction
        07h ???
        08h ???
    BX = ???
    ???
Return: ???
SeeAlso: AH=86h
--------N-2AD800-----------------------------
INT 2A U - Novell NetWare Lite - SERVER - SET ???
    AX = D800h
Return: nothing
Desc:    sets ??? flag, and sets ??? to initial value
Note:    called by CLIENT
SeeAlso: AX=D801h,AX=D850h
--------N-2AD801-----------------------------
INT 2A U - Novell NetWare Lite - SERVER - RESET ???
    AX = D801h
Return: nothing
Desc:    clears the ??? flag set by AX=D800h
Note:    called by CLIENT
SeeAlso: AX=D800h,AX=D850h
--------N-2AD850-----------------------------
INT 2A U - Novell NetWare Lite - CLIENT - INCREMENT ???
    AX = D850h
Return: nothing
Desc:    increments an internal byte-sized counter
Note:    this function is intercepted by DV/X 1.10 PEERSERV.DVR and the
      Advanced NetWare 4.0 DOS Requester
SeeAlso: AX=D851h
--------N-2AD851-----------------------------
INT 2A U - Novell NetWare Lite - CLIENT - RESET ???
    AX = D851h
Return: nothing
Desc:    resets an internal byte-sized counter to zero
Note:    this function is intercepted by DV/X 1.10 PEERSERV.DVR and the
      Advanced NetWare 4.0 DOS Requester
SeeAlso: AX=D850h
--------N-2AD852-----------------------------
INT 2A U - Novell NetWare - DOS Requester v1.03 - ???
    AX = D852h
Return: ???
Note:    calls the NetWare Lite SERVER installation check, and sets ??? pointer
SeeAlso: AX=D853h,INT 2F/AX=D880h
--------N-2AD853-----------------------------
INT 2A U - Novell NetWare - DOS Requester v1.03 - ???
    AX = D853h
Return: ???
Note:    clears the pointer set by AX=D852h
SeeAlso: AX=D852h
--------N-2AE0-------------------------------
INT 2A U - PC Network 1.00 - ???
    AH = E0h
    AL = subfunction??? (01h,02h, maybe others)
    ???
Return: ???
Note:    called by PCNet 1.00 NET.COM, a shell program from which others are run
--------N-2AFF90-----------------------------
INT 2A - PC/TCP PREDIR.EXE - ???
    AX = FF90h
Return: AX = ???
Note:    PREDIR.EXE is the network printer redirector included as part of the
      PC/TCP system by FTP Software, Inc.
--------N-2AFF91-----------------------------
INT 2A - PC/TCP PREDIR.EXE - ???
    AX = FF91h
    BX = ???
Return: AX = status???
--------N-2AFF92-----------------------------
INT 2A - PC/TCP PREDIR.EXE - INSTALLATION CHECK
    AX = FF92h
Return: AX = 0000h if installed
       BX = redirected printer port (FFFFh if no printers redirected)
       CX = version (CH = major, CL = minor)
Note:    PREDIR.EXE is the network printer redirector included as part of the
      PC/TCP system by FTP Software, Inc.
--------N-2AFF93-----------------------------
INT 2A - PC/TCP PREDIR.EXE - ???
    AX = FF93h
Return: AX = ???
--------N-2AFF94-----------------------------
INT 2A - PC/TCP PREDIR.EXE - ???
    AX = FF94h
    BX = ???
    CX = ???
    DX = ???
Return: AX = ???
Note:    PREDIR.EXE is the network printer redirector included as part of the
      PC/TCP system by FTP Software, Inc.
--------N-2AFF95-----------------------------
INT 2A - PC/TCP PREDIR.EXE - GET CONFIGURATION STRINGS
    AX = FF95h
    CX = what to get
        0000h ??? (returned pointer to "C:\COMMAND.COM")
        0001h spooling program
        0002h ???
        0003h spool file name
        0004h swap file name
Return: AX = status
        0000h successful
    BX:DX -> ASCIZ configuration string
--------N-2AFF96-----------------------------
INT 2A - PC/TCP PREDIR.EXE - SET PRINT JOB TERMINATION CONFIGURATION
    AX = FF96h
    CX = what to set
        0000h ???
        0001h print-on-hotkey state
        0002h print-on-exit state
        0003h print job timeout in clock ticks
        0004h print-on-EOF state
    BX = new value (0000h disabled, 0001h enabled except for timeout)
Return: AX = ???
SeeAlso: AX=FF97h
Note:    PREDIR.EXE is the network printer redirector included as part of the
      PC/TCP system by FTP Software, Inc.
--------N-2AFF97-----------------------------
INT 2A - PC/TCP PREDIR.EXE - GET PRINT JOB TERMINATION CONFIGURATION
    AX = FF97h
    CX = what to get
        0000h ???
        0001h print-on-hotkey state
        0002h print-on-exit state
        0003h print job timeout in clock ticks
        0004h print-on-EOF state
Return: AX = status
        0000h successful
    BX = old value (0000h disabled, 0001 enabled except for timeout)
SeeAlso: AX=FF96h
--------D-2B---------------------------------
INT 2B - DOS 2+ - RESERVED
Note:    this vector is not used in DOS versions <= 6.00, and points at an IRET
--------D-2C---------------------------------
INT 2C - DOS 2+ - RESERVED
Note:    this vector is not used in DOS versions <= 6.00, and points at an IRET
--------O-2C---------------------------------
INT 2C - STARLITE architecture - KERNEL API
Note:    STARLITE is an architecture by General Software for a series of MS-DOS
      compatible operating systems (OEM DOS, NETWORK DOS, and SMP DOS) to
      be released in 1991.    The interrupt number is subject to change
      before the actual release.
--------m-2C---------------------------------
INT 2C R - RM386 v6.00 - CLOAKING - CALL PROTECTED-MODE PASSALONG CHAIN
Note:    when this interrupt is invoked in V86 mode, RM386 will invoke the first
      in a chain of protected-mode handlers, and will only pass execution
      to the V86-mode INT 2C handler if none of the handlers in the
      passalong chain handle the call instead.  This is the method by which
      the real-mode stub of a cloaked application communicates with the
      protected-mode portion.
Program: RM386 (RAM-MAN/386) is the memory manager included in Helix Software's
      Netroom
SeeAlso: INT 2C/AX=0009h
--------m-2C0000-----------------------------
INT 2C P - RM386 v6.00 - CLOAKING - ALLOCATE GDT SELECTOR
    AX = 0000h
    EBX = base address
    CL = access mode byte
    CH = extended access mode byte (omit limit field)
    EDX = segment limit
Return: CF clear if successful
        AX = selector
    CF set on error
        AX = error code (see below)
Program: RM386 (RAM-MAN/386) is the memory manager included in Helix Software's
      Netroom
Note:    this INT 2C interface is used by Netroom's DPMI.EXE v3.00
SeeAlso: AX=0001h,AX=0002h,AX=0003h,AX=0004h,AX=0005h,INT 31/AH=57h

Values for error code:
 0001h    no more selectors
 0002h    not a GDT ring 0 selector
 0003h    invalid selector (out of range, not user selector)
 0004h    selector not allocated
--------m-2C0001-----------------------------
INT 2C P - RM386 v6.00 - CLOAKING - FREE GDT SELECTOR
    AX = 0001h
    SI = selector
Return: CF clear if successful
    CF set on error
        AX = error code (see AX=0000h)
SeeAlso: AX=0000h
--------m-2C0002-----------------------------
INT 2C P - RM386 v6.00 - CLOAKING - SET SEGMENT BASE ADDRESS
    AX = 0002h
    SI = selector
    EBX = new physical base addres
Return: CF clear if successful
    CF set on error
        AX = error code (see AX=0000h)
Return: AX=0000h,AX=0003h,AX=0004h,INT 31/AX=0007h
--------m-2C0003-----------------------------
INT 2C P - RM386 v6.00 - CLOAKING - SET SEGMENT LIMIT
    AX = 0003h
    SI = selector
    EBX = new limit
Return: CF clear if successful
    CF set on error
        AX = error code (see AX=0000h)
SeeAlso: AX=0000h,AX=0002h,AX=0004h,INT 31/AX=0008h
--------m-2C0004-----------------------------
INT 2C P - RM386 v6.00 - CLOAKING - SET SEGMENT ACCESS MODE
    AX = 0004h
    SI = selector
    CL = new access mode byte
Return: CF clear if successful
    CF set on error
        AX = error code (see AX=0000h)
SeeAlso: AX=0000h,AX=0002h,AX=0003h,AX=0005h,INT 31/AX=0009h
--------m-2C0005-----------------------------
INT 2C P - RM386 v6.00 - CLOAKING - SET SEGMENT EXTENDED ACCESS MODE
    AX = 0005h
    SI = selector
    CL = new extended access mode byte (limit field ignored)
Return: CF clear if successful
    CF set on error
        AX = error code (see AX=0000h)
SeeAlso: AX=0000h,AX=0002h,AX=0003h,AX=0004h,INT 31/AX=0009h
--------m-2C0006-----------------------------
INT 2C P - RM386 v6.00 - CLOAKING - GET PROTECTED-MODE INTERRUPT VECTOR
    AX = 0006h
    CL = vector
Return: CF clear
    DX:EBX -> current interrupt handler
SeeAlso: AX=0007h,INT 31/AX=0204h
--------m-2C0007-----------------------------
INT 2C P - RM386 v6.00 - CLOAKING - SET PROTECTED-MODE INTERRUPT VECTOR
    AX = 0007h
    CL = vector
    DX:EBX -> interrupt handler
Return: CF clear
SeeAlso: AX=0006h,INT 31/AX=0205h
--------m-2C0008-----------------------------
INT 2C P - RM386 v6.00 - CLOAKING - GET PASSALONG ADDRESS
    AX = 0008h
Return: CF clear
    DX:EBX = current passalong address
SeeAlso: AX=0009h,AX=002Ch
--------m-2C0009-----------------------------
INT 2C P - RM386 v6.00 - CLOAKING - SET PASSALONG ADDRESS
    AX = 0009h
    DX:EBX = new value for passalong address
Return: CF clear
Note:    when an INT 2C instruction is executed in V86 mode, RM386 calls the
      passalong address.  The handler should check whether the upcall
      is of interest to it, and if not it should jump to the old passalong
      address (retrieved with AX=0008h before the handler was installed)
SeeAlso: AX=0008h,AX=002Dh,INT 2C"CLOAKING"

Passalong address called with:
    EAX = CS:IP of byte following INT 2C instruction invoking passalong
    SS:EBX -> caller registers (see below)
    CF clear
    others undefined
Return: CF clear: pass along to V86-mode INT 2C handler
    CF set: return immediately to V86 mode

Format of caller registers:
Offset    Size    Description
 00h    DWORD    EDI
 04h    DWORD    ESI
 08h    DWORD    EBP
 0Ch    DWORD    reserved (ESP from PUSHAD instruction)
 10h    DWORD    EBX
 14h    DWORD    EDX
 18h    DWORD    ECX
 1Ch    DWORD    EAX
 20h    DWORD    error code
 24h    DWORD    EIP
 28h    WORD    CS
 2Ah    WORD    padding
 2Ch    DWORD    EFLAGS
 30h    DWORD    ESP
 34h    WORD    SS
 36h    WORD    padding
--remainder not available if protected-mode ring3 trap---
 38h    WORD    ES
 3Ah    WORD    padding
 3Ch    WORD    DS
 3Eh    WORD    padding
 40h    WORD    FS
 42h    WORD    padding
 44h    WORD    GS
 46h    WORD    padding
--------m-2C000A-----------------------------
INT 2C P - RM386 v6.00 - CLOAKING - GET BASE ADDRESS OF GDT SELECTOR
    AX = 000Ah
    SI = selector
Return: CF clear if successful
        EBX = segment base address
    CF set on error
        AX = error code (see AX=0000h)
Program: RM386 (RAM-MAN/386) is the memory manager included in Helix Software's
      Netroom
SeeAlso: AX=0000h,AX=0002h,AX=000Bh
--------m-2C000B-----------------------------
INT 2C P - RM386 v6.00 - CLOAKING - GET SELECTOR LIMIT
    AX = 000Bh
    SI = selector
Return: CF clear if successful
        EBX = segment base address
    CF set on error
        AX = error code (see AX=0000h)
SeeAlso: AX=000Ah
--------m-2C---------------------------------
INT 2C P - RM386 v6.00 - CLOAKING - RESERVED FOR CLOAKED BIOS USE UNDER WINDOWS
    AX = function (000Ch-001Fh)
--------m-2C0020-----------------------------
INT 2C P - RM386 v6.00 - CLOAKING - GET SIZE OF PROTECTED-MODE STATE
    AX = 0020h
Return: EAX = number of bytes required for storing state
SeeAlso: AX=0021h,AX=0022h
--------m-2C0021-----------------------------
INT 2C P - RM386 v6.00 - CLOAKING - SAVE PROTECTED-MODE STATE
    AX = 0021h
    ES:EDI -> buffer for protected-mode state
Return: CF clear
    buffer filled
SeeAlso: AX=0020h,AX=0022h
--------m-2C0022-----------------------------
INT 2C P - RM386 v6.00 - CLOAKING - RESTORE PROTECTED-MODE STATE
    AX = 0022h
    DS:ESI -> buffer containing previously-saved protected-mode state
Return: CF clear if successful
        state restored
    CF set on error (invalid buffer contents)
SeeAlso: AX=0020h,AX=0021h
--------m-2C0023-----------------------------
INT 2C P - RM386 v6.00 - CLOAKING - ISSUE PROTECTED-MODE XMS CALL
    AX = 0023h
Note:    not currently implemented--NOP in RM386 v6.00
--------m-2C0024-----------------------------
INT 2C P - RM386 v6.00 - CLOAKING - SET V86-MODE STACK
    AX = 0024h
    DX:EBX = new value for V86-mode SS:ESP
Return: nothing
--------m-2C0025-----------------------------
INT 2C P - RM386 v6.00 - CLOAKING - CALL V86-MODE PROCEDURE
    AX = 0025h
    DS:EBX -> client register structure (see AX=0009h)
Return: CF clear if successful
        client register structure updated
    CF set if no more nested procedure call space available
Note:    this call uses the V86-mode stack supplied in the client structure, and
      calls the routine specified by CS:IP in the client structure
SeeAlso: AX=0026h,AX=0027h,INT 31/AX=0301h
--------m-2C0026-----------------------------
INT 2C P - RM386 v6.00 - CLOAKING - CALL V86-MODE INTERRUPT HANDLER
    AX = 0026h
    DS:EBX -> client register structure (see AX=0009h)
    CX = interrupt number
Return: CF clear if successful
        client register structure updated
    CF set if no more nested procedure call space available
Note:    this call uses the V86-mode stack supplied in the client structure
SeeAlso: AX=0025h,AX=0027h,INT 31/AX=0300h
--------m-2C0027-----------------------------
INT 2C P - RM386 v6.00 - CLOAKING - CHAIN TO V86-MODE INTERRUPT HANDLER
    AX = 0027h
    DS:EBX -> client register structure (see AX=0009h)
Return: CF clear if successful
        client register structure updated
    CF set if no more nested procedure call space available
Note:    this call uses the V86-mode stack supplied in the client structure,
      and jumps to the address specified by CS:IP in the client structure
SeeAlso: AX=0025h,AX=0026h
--------m-2C0028-----------------------------
INT 2C P - RM386 v6.00 - CLOAKING - GET ESP0 FROM TSS
    AX = 0028h
Return: CF clear
    EAX = TSS's ESP0
Program: RM386 (RAM-MAN/386) is the memory manager included in Helix Software's
      Netroom
--------m-2C0029-----------------------------
INT 2C P - RM386 v6.00 - CLOAKING - SET SECONDARY STACK
    AX = 0029h
    DX:EBX = new value for SS:ESP of ring 3 secondary stack
Return: CF clear
Desc:    inform RM386 of the ring 3 interrupt stack location
--------m-2C002A-----------------------------
INT 2C P - RM386 v6.00 - CLOAKING - SET 8259 IRQ BASE VECTORS
    AX = 002Ah
    BL = base vector of master interrupt controller
    CL = base vector of slave interrupt controller
Note:    this call merely informs RM386 that the caller has changed the
      interrupt mappings
SeeAlso: INT 67/AX=DE0Bh
--------m-2C002BCH81-------------------------
INT 2C P - RM386 v6.00 - CLOAKING - PROTECTED-MODE VIRTUAL DMA SERVICES
    AX = 002Bh
    CH = 81h
    CL = subfunction (02h-0Ch)
    other registers as appropriate for subfunction
Return: varies by function
    CF set on error
Note:    these functions are equivalent to the INT 4B/AX=81xxh subfunctions
      with the same numbers
SeeAlso: INT 4B/AX=8102h,INT 4B/AX=810Ch
--------m-2C002C-----------------------------
INT 2C P - RM386 v6.00 - CLOAKING - GET PORT-TRAPPING PASSALONG
    AX = 002Ch
Return: CF clear
    DX:EBX = current I/O trapping passalong address
SeeAlso: AX=0008h,AX=002Dh
--------m-2C002D-----------------------------
INT 2C P - RM386 v6.00 - CLOAKING - SET PORT-TRAPPING PASSALONG
    AX = 002Dh
    DX:EBX = new I/O trapping passalong address
Return: CF clear
Note:    RM386 calls the passalong address whenever an access to a monitored
      I/O port is attempted; the handler should check whether it is a port
      that it is interested in, and if not call the previous passalong
      address (which was retrieved with AX=002Ch before installing the
      new handler)
SeeAlso: AX=0009h,AX=002Ch,INT 67/AX=5DEAh

Port-trapping passalong address called with:
    EAX = CS:IP of faulting instruction (unless executing in protected-mode
        ring 3)
    SS:EBX -> caller register structure (see AX=0009h)
        check EFLAGS V86-mode bit for type
    CX = first two bytes of I/O instruction which was trapped
    DX = port to which I/O is being performed
    CF clear
Return: CF clear if RM386 should perform I/O operation
    CF set if I/O should be skipped
Note:    RM386 skips the trapped I/O instruction, so the passalong handler
      should not modify the client CS:EIP
--------m-2C002E-----------------------------
INT 2C P - RM386 v6.00 - CLOAKING - TRAP I/O PORT
    AX = 002Eh
    DX = port number to trap
Return: CF clear if successful
    CF set on error (port out of range or reserved)
Program: RM386 (RAM-MAN/386) is the memory manager included in Helix Software's
      Netroom
SeeAlso: AX=002Fh,AX=0030h
--------m-2C002F-----------------------------
INT 2C PU - RM386 v6.00 - CLOAKING - UNTRAP I/O PORT
    AX = 002Fh
    DX = port number for which to cancel trapping
Return: CF clear if successful
    CF set on error (port out of range or reserved)
SeeAlso: AX=002Eh,AX=0030h
--------m-2C0030-----------------------------
INT 2C PU - RM386 v6.00 - CLOAKING - GET TRAPPING STATE OF SPECIFIED PORT
    AX = 0030h
    DX = port number
Return: CF clear if successful
       BX = current state (0000h not trapped, 0001h trapped)
    CF set on error (port out of range or reserved)
SeeAlso: AX=002Eh,AX=002Fh
--------m-2C0031-----------------------------
INT 2C PU - RM386 v6.00 - BUG
    AX = 0031h
Program: RM386 (RAM-MAN/386) is the memory manager included in Helix Software's
      Netroom
Note:    due to a fencepost error, RM386 v6.00 will branch unpredictably if
      invoked with this function
--------D-2D---------------------------------
INT 2D - DOS 2+ - RESERVED
Note:    this vector is not used in DOS versions <= 6.00, and points at an IRET
--------t-2D---------------------------------
INT 2D - ALTERNATE MULTIPLEX INTERRUPT SPECIFICATION (AMIS) [v3.5.1]
    AH = multiplex number
    AL = function
        00h installation check
        Return: AL = 00h if free
            AL = FFh if multiplex number in use
                CX = binary version number (CH = major, CL = minor)
                DX:DI -> signature string (see below) identifying
                    the program using the multiplex number
        01h get entry point
        Return: AL = 00h if all API calls via INT 2D
            AL = FFh if entry point supported
                DX:BX -> entry point for bypassing interrupt chain
        02h uninstall
        DX:BX = return address for successful uninstall (may be
            ignored by TSR)
        Return: AL = status
                00h not implemented
                01h unsuccessful
                02h can not uninstall yet, will do so when able
                03h safe to remove, but no resident uninstaller
                (TSR still enabled)
                BX = segment of memory block with resident code
                04h safe to remove, but no resident uninstaller
                (TSR now disabled)
                BX = segment of memory block with resident code
                05h not safe to remove now, try again later
                FFh successful
            return at DX:BX with AX destroyed if successful and
              TSR honors specific return address
        03h request pop-up
        Return: AL = status
                00h not implemented or TSR is not a pop-up
                01h can not pop up at this time, try again later
                02h can not pop up yet, will do so when able
                03h already popped up
                04h unable to pop up, user intervention required
                BX = standard reason code
                    0000h unknown failure
                    0001h interrupt chain passes through memory
                      which must be swapped out to pop up
                    0002h swap-in failed
                CX = application's reason code if nonzero
                FFh TSR popped up and was exited by user
                BX = return value
                    0000h no return value
                    0001h TSR unloaded
                    0002h-00FFh reserved
                    0100h-FFFFh application-dependent
        04h determine chained interrupts
        BL = interrupt number (except 2Dh)
        Return: AL = status
                00h not implemented
                01h (obsolete) unable to determine
                02h (obsolete) interrupt hooked
                03h (obsolete) interrupt hooked, address returned
                DX:BX -> TSR's interrupt BL handler
                04h list of hooked interrupts returned
                DX:BX -> interrupt hook list (see below)
                FFh interrupt not hooked
        Notes:    since INT 2D is known to be hooked, the resident code
              need not test for BL=2Dh (to minimize its size), and
              the return value is therefore undefined in that case.
            BL is ignored if the TSR returns AL=04h; in that case,
              the caller needs to scan the return list rather than
              making additional calls to this function.  If the
              return is not 00h or 04h, then the caller must cycle
              through the remaining interrupt numbers it wishes to
              check.
            return values 01h thru 03h are disparaged and will be
              removed from the next version of this specification;
              they are included for compatibility with version 3.3,
              though they were probably never used in any
              implementation
        05h get hotkeys
        Return: AL = status
                00h not implemented
                FFh supported
                DX:BX -> hotkey list (see below)
        06h-0Fh reserved for future enhancements
        Return: AL = 00h (not implemented)
        other  application-dependent
Notes:    programs should not use fixed multiplex numbers; rather, a program
      should scan all multiplex numbers from 00h to FFh, remembering the
      first unused multiplex in case the program is not yet installed.
      For multiplex numbers which are in use, the program should compare
      the first 16 bytes of the signature string to determine whether it
      is already installed on that multiplex number.  If not previously
      installed, it should use the first free multiplex number.
    functions other than 00h are not valid unless a program is installed
      on the selected multiplex number
    to be considered fully compliant with version 3.5 of the specification,
      programs must implement at least functions 00h, 02h (no resident
      uninstall code required), and 04h (return value 04h).     TSRs that
      provide hotkeys with which the user can activate them must also
      implement function 05h.  The absolute minimum fully-compliant
      implementation has an overhead of 64 bytes (80 bytes with function
      05h) plus 22 bytes per hooked interrupt (for the interrupt sharing
      protocol header and hook list entry).
    the signature string and description may be used by memory mappers
      to display the installed programs
    users of this proposal should adhere to the IBM interrupt sharing
      protocol (see below), which will permit removal of TSRs in
      arbitrary order and interrupt handler reordering.  All TSRs
      following this proposal should be removable, though they need not
      keep the code for removing themselves resident; it is acceptable
      for a separate program to perform the removal.
    A sample implementation including example TSRs and utility programs
      may be found in a separate package distributed as AMISLnnn.ZIP
      (AMISL091.ZIP as of this writing).
    Please let me know if you choose to follow this proposal.  The
      signature and a list of the private API calls you use would be
      appreciated, as well.
SeeAlso: INT 2F
Index:    installation check;Alternate Multiplex Interrupt Specification
Index:    installation check;AMIS|installation check;FASTMOUS
Index:    installation check;SPELLER|installation check;Monitor
Index:    installation check;NOLPT|installation check;NOTE
Index:    installation check;RBkeyswp|installation check;SWITCHAR
Index:    installation check;VGABLANK|installation check;EATMEM
Index:    installation check;RECALL|installation check;XPTR2
Index:    uninstall;Alternate Multiplex Interrupt Specification|uninstall;AMIS
Index:    entry point;Alternate Multiplex Interrupt|entry point;AMIS

Format of signature string:
Offset    Size    Description
 00h  8 BYTEs    blank-padded manufacturer's name (possibly abbreviated)
 08h  8 BYTEs    blank-padded product name
 10h 64 BYTEs    ASCIZ product description (optional, may be a single 00h)
Note:    it is not necessary to reserve a full 64 bytes for the description,
      just enough to store the actual ASCIZ string

Format of interrupt hook list [array]:
Offset    Size    Description
 00h    BYTE    interrupt number (last entry in array is 2Dh)
 01h    WORD    offset within hook list's segment of the interrupt handler
        this will point at the initial short jump of the interrupt
        sharing protocol header (see below)

Format of hotkey list:
Offset    Size    Description
 00h    BYTE    type of hotkey checking
        bit 0: checks before chaining INT 09
        bit 1: checks after chaining INT 09
        bit 2: checks before chaining INT 15/AH=4Fh
        bit 3: checks after chaining INT 15/AH=4Fh
        bit 4: checks on INT 16/AH=00h,01h,02h
        bit 5: checks on INT 16/AH=10h,11h,12h
        bit 6: checks on INT 16/AH=20h,21h,22h
        bit 7: reserved (0)
 01h    BYTE    number of hotkeys (may be zero if TSR can disable hotkeys)
 02h 6N BYTEs    array of hotkey definitions
        (one per hotkey, first should be primary hotkey)
        Offset    Size    Description
         00h    BYTE    hotkey scan code (00h/80h if shift states only)
                hotkey triggers on release if bit 7 set
         01h    WORD    required shift states (see below)
         03h    WORD    disallowed shift states (see below)
         05h    BYTE    flags
                bit 0: hotkey chained before processing
                bit 1: hotkey chained after processing
                bit 2: others should pass through this hotkey
                    so that it can be monitored
                bit 3: hotkey will not activate if other keys
                    pressed/released before hotkey press is
                    completed
                bit 4: this key is remapped into some other key
                bit 5-7: reserved (0)
Notes:    except for bit 7, the shift states correspond exactly to the return
      values from INT 16/AH=12h.  A set bit in the required states word
      indicates that the corresponding shift state must be active when the
      hotkey's scan code is received for the hotkey to be recognized; a
      clear bit means that the corresponding state may be ignored.    A set
      bit in the disallowed shift states word indicates that the
      corresponding shift state must be inactive.
    if bit 2 is set, either control key may be pressed for the hotkey; if
      bits 8 and 10 are both set, then both control keys must be pressed.
      Similarly for bits 3 and 9/11, as well as 7 and 0/1.
    for the disallowed-states word, if one of the "either" bits is set,
      then both the corresponding left bit and right bit must be set
    examples:
        Ctrl-Alt-Del monitoring: 53h 000Ch 0003h 06h
        Alt-key tap (DESQview):     B8h 0000h 0007h 08h
        Shf-Shf-N (NOTE.COM):     31h 0003h 000Ch 00h
Index:    hotkeys;AMIS

Bitfields for shift states:
 bit 0    right shift pressed
 bit 1    left shift pressed
 bit 2    either control key pressed
 bit 3    either Alt key pressed
 bit 4    ScrollLock active
 bit 5    NumLock active
 bit 6    CapsLock active
 bit 7    either shift key pressed
 bit 8    left control key pressed
 bit 9    left Alt key pressed
 bit 10 right control key pressed
 bit 11 right Alt key pressed
 bit 12 ScrollLock pressed
 bit 13 NumLock pressed
 bit 14 CapsLock pressed
 bit 15 SysRq key pressed

Format of interrupt sharing protocol interrupt handler entry point:
Offset    Size    Description
 00h  2 BYTEs    short jump to actual start of interrupt handler, immediately
        following this data block (EBh 10h)
 02h    DWORD    address of next handler in chain
 06h    WORD    signature 424Bh
 08h    BYTE    EOI flag
        00h software interrupt or secondary hardware interrupt handler
        80h primary hardware interrupt handler (will issue EOI)
 09h  2 BYTEs    short jump to hardware reset routine
        must point at a valid FAR procedure (may be just RETF)
 0Bh  7 BYTEs    reserved (0)

Signatures known to be in use:
 'Byrial J' 'EKLAVO  '    permits keyboard entry of Esperanto accented letters
 'CoveSoft' 'Burnout+'    shareware screen saver Burnout Plus
 'Crynwr  ' 'SPELLER '    TSR spelling-checker
 'CSJewell' 'Modula3L'    Curtis Jewell's Modula-3 compiler (non-TSR)
 'DAISYCHA' 'INDRIVER'    Advanced Parallel Port daisy chain driver (vendor name
            in product description field, if desired)
            (see also INT 2D/AL=DCh)
 'ECLIPSE ' 'PLUMP   '    Eclipse Software's printer and plotter spooler
 'GraySoft' 'GIPC    '    GraySoft's Inter-Process Communications driver
 'heathh  ' 'Monitor '
 'J. Berry' 'RATSR   '    RemoteAccess Network Manager workstation module
 'JWB      ' 'RAMLIGHT'    James Birdsall's on-screen RAMdisk activity indicator
 'Nildram ' 'ST         '    Screen Thief graphics screen grabber
 'R-Ware  ' 'dLite   '    run-time data decompression TSR
 'Ralf B  ' 'FASTMOUS'    example TSR included with sample AMIS library code
 'Ralf B  ' 'NOLPT n '    example TSR -- turn LPTn into bit-bucket
 'Ralf B  ' 'NOTE    '    example TSR -- popup note-taker
 'Ralf B  ' 'RBkeyswp'    RBkeyswap v3.0+ -- swap Esc/~ and LCtrl/CapsLock keys
 'Ralf B  ' 'SWITCHAR'    example TSR -- add switchar() support removed from DOS5
 'Ralf B  ' 'VGABLANK'    example TSR -- VGA-only screen blanker
 'Sally IS' 'Mdisk   '    removeable, resizeable RAMdisk
 'Sally IS' 'Scr2Tex '    screen dumper with output in (La)Tex format
 'Thaco      ' 'NEST    '    Eirik Pedersen's programmer's delimiter matcher
 'TifaWARE' 'EATMEM  '    George A. Theall's public domain memory restrictor for
            testing programs (v1.1+)
 'TifaWARE' 'RECALL  '    public domain commandline editor and history (v1.2+)
 'Todd      ' 'XPTR2   '    PC-to-Transputer interface by Todd Radel
--------N-2D--10-----------------------------
INT 2D - RATSR 2.0+ - GET STATUS
    AL = 10h
    AH = AMIS multiplex number for RATSR
Return: AL = status
        01h listening (no connection)
        02h receiving          \
        03h sending               > station being monitored
        04h initializing receive  /
    AH = keyboard lock status (00h unlocked, 01h locked)
Program: RATSR is a utility by James Berry provided with
      RemoteAccess/Professional, a commercial bulletin board system, that
      allows remote control of a station over a network
SeeAlso: INT 2D"AMIS"
--------d-2D--10-----------------------------
INT 2D - dLite 1.0+ - GET PARAMETER BLOCK ADDRESS
    AL = 10h
    AH = AMIS multiplex number for dLite
Return: CF clear if successful
        ES:BX -> parameter block (see below)
    CF set on error
Program: dLite is a shareware TSR by Rainer Schuetze which transparently
      expands compressed files when they are read
SeeAlso: AL=11h"dLite",AL=12h"dLite",INT 21/AX=FEDCh"PCMANAGE"

Format of parameter block:
Offset    Size    Description
 00h    BYTE    TSR flags
        bit 0: deny FCB access
        bit 1: dLite sleeping rather than activated
        bit 2: always indicate original filesize when reading
            directory entries, rather than only for specified
            programs
        bits 3-7 reserved
 01h    WORD    maximum number of programs needing original filesize
 03h    WORD    current number of programs needing original filesize
 05h    WORD    maximum number of files that can be handled by dLite (should
        be the same as FILES= in CONFIG.SYS)
 07h    WORD    offset (in the same segment as the parameter block) of the
        table of programs needing the original filesize (8 bytes each,
        without path or extension, uppercase, and zero terminated if
        shorter than 8 bytes)
--------V-2D--10-----------------------------
INT 2D - Burnout Plus v3.00 - GET STATE/CONTROL INFORMATION
    AL = 10h
    AH = AMIS multiplex number for Burnout Plus
Return: AL = 01h
    BX = Burnout Plus status (see below)
    CX = Record of features loaded (see below)
    ES:DI -> Burnout Plus control structure (see below)
Program: Burnout Plus is a DOS screen saver from Cove Software
SeeAlso: INT 2D"AMIS"
Index:    screen saver;Burnout Plus

Bitfields for status:
 bit 0    screen is blanked
 bit 1    MS Windows is active (Burnout Plus deactivated)
 bits 2-15 reserved

Bitfields for features loaded/features enabled:
 bit 0    mouse activity monitor
 bit 1    passkey support
 bit 2    password support
 bit 3    continuous clear
 bit 4    software blanking
 bit 5    video activity monitor
 bit 6    disk activity monitor
 bit 7    activating keystroke suppression

Format of Burnout Plus control structure:
Offset    Size    Description
 00h    BYTE    size of structure in bytes
 01h    WORD    Burnout Plus version
 03h    WORD    screen blanking reset count in clock ticks
 05h    WORD    current countdown value in clock ticks
 07h    BYTE    type of timeout specification
 08h    BYTE    instant-blank hotkey
 09h    WORD    extended status information (see below)
        the bits for password, passkey, and software blanking are
          ignored and cannot be enabled or disabled externally
 0Bh    WORD    features enabled (see above)
Note:    all fields except the first two may be modified by external programs
      to affect the operation of Burnout Plus
Index:    hotkeys;Burnout Plus

Bitfields for extended status information:
 bit 0    Burnout Plus disabled
 bit 1    force screen to blank on next clock tick
 bit 2    restore screen if currently blanked
 bits 3-15 reserved
Note:    bits 1 and 2 are automatically cleared by Burnout Plus after blanking
      or restoring the screen
--------V-2D--10-----------------------------
INT 2D U - Screen Thief v1.00 - FREE HIGH MEMORY BUFFERS
    AL = 10h
    AH = AMIS multiplex number for Screen Thief
Return: nothing
Program: Screen Thief is a graphics screen grabber
Note:    releases any code and data stored in EMS, DOS UMBs, or XMS UMBs, but
      does not release the low-memory stub; this may be used to effect a
      partial uninstall if INT 2D/AL=02h fails
SeeAlso: INT D8"Screen Thief"
--------i-2D--10-----------------------------
INT 2D U - RAMLIGHT v1.0 - GET MONITORING INFORMATION
    AL = 10h
    AH = AMIS multiplex number for RAMLIGHT
Return: ES:BX -> array of fake device driver headers used in monitoring
    CX = number of drives being monitored???
--------d-2D--11-----------------------------
INT 2D - dLite 1.0+ - CHECK FOR dPressed FILE AND GET ORIGINAL SIZE
    AL = 11h
    AH = AMIS multiplex number for dLite
    BX = file handle
Return: CF clear if successful
        DX:AX = size of uncompressed file
    CF set on error (not dPressed file)
SeeAlso: AL=10h"dLite",AL=12h"dLite"
--------d-2D--12-----------------------------
INT 2D - dLite 1.0+ - CHECK FOR dPressed FILE AND GET COMPRESSED SIZE
    AL = 12h
    AH = AMIS multiplex number for dLite
    BX = file handle
Return: CF clear if successful
        DX:AX = size of compressed file
    CF set on error (not dPressed file)
SeeAlso: AL=10h"dLite",AL=11h"dLite"
--------b-2D--DC-----------------------------
INT 2D C - DAISY.SYS - BROADCAST: CHAIN RESCANNED
    AL = DCh
    AH = AMIS multiplex number for signature 'DAISYCHA' 'INDRIVER'
    DL = LPT Port Rescanned
Program: DAISY.SYS is a daisy chain manager for parallel port peripherals
      conforming to the Advanced Parallel Port Committee's daisy chain
      specification.
Desc:    This Broadcast is sent whenever daisy chain IDs are reassigned to
      warn parallel port device drivers that their daisy chain ID may
      have been changed.
Note:    This function is a callout from DAISY.SYS, NOT a call into DAISY.SYS
SeeAlso: INT 17/AX=0200h"Advanced Parallel Port"
--------l-2E---------------------------------
INT 2E U - DOS 2+ - PASS COMMAND TO COMMAND INTERPRETER FOR EXECUTION
    DS:SI -> commandline to execute (see below)
Return: all registers except CS:IP destroyed
    AX = status (4DOS v4.0)
       0000h successful
       FFFFh error before processing command (not enough memory, etc)
       other error number returned by command
Notes:    this call allows execution of arbitrary commands (including COMMAND.COM
      internal commands) without loading another copy of COMMAND.COM
    if COMMAND.COM is the user's command interpreter, the primary copy
      executes the command; this allows the master environment to be
      modified by issuing a "SET" command, but changes in the master
      environment will not become effective until all programs descended
      from the primary COMMAND.COM terminate
    since COMMAND.COM processes the string as if typed from the keyboard,
      the transient portion needs to be present, and the calling program
      must ensure that sufficient memory to load the transient portion can
      be allocated by DOS if necessary
    results are unpredictable if invoked by a program run from a batch file
      because this call is not reentrant and COMMAND.COM uses the same
      internal variables when processing a batch file
    hooked but ignored by 4DOS v3.0 COMMAND.COM replacement unless SHELL2E
      has been loaded
    the MS-DOS 5 Programmer's Reference calls this "Reload Transient"

Format of commandline:
Offset    Size    Description
 00h    BYTE    length of command string, not counting trailing CR
 01h    var    command string
  N    BYTE    0Dh (CR)
--------O-2E---------------------------------
INT 2E UP - Windows NT - NATIVE API
    EAX = function number
    EDX = address of parameter block
Return: ???
--------l-2E----BXE22E-----------------------
INT 2E - 4DOS v2.x-3.03 SHELL2E.COM - UNINSTALL
    BX = E22Eh
    DS:SI -> zero byte
Return: if successful, SHELL2E terminates itself with INT 21/AH=4Ch
----------2F---------------------------------
INT 2F - Multiplex - NOTES
    AH = identifier of program which is to handle the interrupt
       00h-7Fh reserved for DOS
       B8h-BFh reserved for networks
       C0h-FFh reserved for applications
    AL is the function code
   This is a general mechanism for verifying the presence of a TSR and
   communicating with it.  When searching for a free identifier code for AH
   using the installation check (AL=00h), the calling program should set
   BX/CX/DX to 0000h and must not depend on any registers other than CS:IP
   and SS:SP to be valid on return, since numerous programs now use additional
   registers on input and/or output for the installation check.
Notes:    Since the multiplex chain is growing so long, and beginning to
      experience multiplex number collisions, I am proposing an alternate
      multiplex interrupt on INT 2D.  If you decide to use the alternate
      multiplex, please let me know.
    DOS and some other programs return values in the flags register, so
      any TSR which chains by calling the previous handler rather than
      jumping to it should ensure that the returned flags are preserved
      and passed back to the original caller
SeeAlso: INT 2D
--------t-2F---------------------------------
INT 2F - BMB Compuscience Canada Utilities Interface - INSTALLATION CHECK
    AH = xx (dynamically assigned based upon a search for a multiplex
         number which doesn't answer installed)
    AL = 00h installation check
    ES:DI = EBEBh:BEBEh
Return: AL = 00h not installed
         01h not installed, not OK to install
         FFh installed; if ES:DI was EBEBh:BEBEh on entry, ES:DI will point
         to a string of the form 'MMMMPPPPPPPPvNNNN' where MMMM is a
         short form of the manufacturer's name, PPPPPPPP is a product
         name and NNNN is the product's version number
--------t-2F---------------------------------
INT 2F - Ross Wentworth's Turbo Pascal POPUP LIBRARY
    AH = programmer-selected multiplex number
    AL = function
        00h installation check
        Return: AL = FFh if installed
        01h get TSR interrupt vectors
        Return: DX:AX -> vector table (see below)
        02h get TSR code segment
        Return: AX = code segment for all interrupt handlers
        03h call user exit routine and release TSR's memory
        04h get signature string
        Return: DX:AX -> counted string containing signature
        05h get TSR's INT 2F handler
        Return: DX:AX -> INT 2F handler
        06h enable/disable TSR
        BL = new state (00h disabled, 01h enabled)
        07h activate TSR (popup if not disabled)
        08h get hotkeys
        BL = which hotkey (00h = hotkey 1, 01h = hotkey 2)
        Return: AX = hotkey (AH = keyflags, AL = scancode)
        09h set hotkey
        BL = which hotkey (00h = hotkey 1, 01h = hotkey 2)
        CX = new hotkey (CH = keyflags, CL = scancode)
        0Ah-1Fh reserved
Index:    installation check;Ross Wentworth POPUP library
Index:    hotkeys;Ross Wentworth POPUP library

Format of vector table entry:
Offset    Size    Description
 00h    BYTE    vector number (00h = end of table)
 01h    DWORD    original vector
 05h    WORD    offset of interrupt handler in TSR's code segment
--------t-2F---------------------------------
INT 2F - CiriSOFT Spanish University of Valladolid TSR's Interface
    AH = xx (dynamically assigned based upon a search for a multiplex
         number from C0h to FFh which doesn't answer installed)
    AL = 00h installation check
    ES:DI = 1492h:1992h
Return: AL = 00h not installed
         01h not installed, not OK to install
         FFh installed; and if ES:DI was 1492h:1992h on entry, ES:DI will
         point to author_name_ver table (see below)
    AH = FFh
Note:    this interface permits advanced communication with TSRs: it is possible
      to make a generic uninstall utility, advanced TSR relocator programs
      in order to fit fragmented memory areas, etc.
See also: INT 2D"AMIS",INT 2F"Compuscience"
Index:    installation check;CiriSOFT TSR interface
Index:    uninstall;CiriSOFT TSR interface

Format of author_name_ver table:
Offset    Size    Description
 -16    WORD    segment of the start of the resident TSR code (CS in programs
        with PSP, XMS upper memory segment if installed as UMB...)
 -14    WORD    offset of the start of the resident TSR code (frequently 100h
        in *.COM programs and 0 in upper memory TSR's).
 -12    WORD    memory used by TSR (in paragraphs). Knowing the memory area
        used by TSR is possible to determine if hooked vectors are
        still pointing it (and if it is safe to uninstall).
 -10    BYTE    characteristics byte
        bits 0-2: 000 normal program (with PSP)
              001 upper XMS memory block (needed HIMEM.SYS function
                  to free memory when uninstalling)
              010 device driver (*.SYS)
              011 device driver in EXE format
              1xx others (reserved)
        bits 3-6 reserved
        bit 7 set if extra_table defined and supported
 -9    BYTE    number of multiplex entry used (redefinition available). Note
        that the TSR must use THIS variable in it's INT 2Fh handler.
 -8    WORD    offset to vector_area table (see below)
 -6    WORD    offset to extra_area table (see bit 7 in offset -10 and below)
 -4   4 BYTEs    signature string "*##*"
 00h    var    "AUTHOR:PROGRAM_NAME:VERSION",0     (variable length, this area
        is used in order to determine if the TSR is already resident
        and it's version code; the ':' char is used as delimiter)

Format of vector_area table:
Offset    Size    Description
 -1    BYTE    number of vectors intercepted by TSR
 00h    BYTE    first vector number
 01h    DWORD    first vector pointer before installing the TSR
 05h    BYTE    second vector number
 06h    DWORD    second vector pointer before installing the TSR
 0Ah    ...    (and so on)
Note:    the TSR must use these variables to invoke the previous interrupt
      handler routines

Format of extra_area table (needed only to improve relocation feature):
Offset    Size    Description
 00h    WORD    offset to external_ctrl table (0 if not supported)
 02h    WORD    reserved for future use (0)

Format of external_ctrl table:
Offset    Size    Description
 00h    BYTE    bit 0: TSR is relocatable (no absolute segment references)
 01h    WORD    offset to a variable which can activate/inhibit the TSR
 ---And if bit 0 in offset 00h is off:
 03h    DWORD    pointer to ASCIZ pathname for executable file which supports
        /SR parameter (silent installation & inhibit)
 07h    DWORD    pointer to first variable to initialize on the copy reloaded
        from the previous TSR still resident
 0Bh    DWORD    pointer to last variable (all variables packed in one block)
--------c-2F00-------------------------------
INT 2F U - DOS 2.x only PRINT.COM - ???
    AH = 00h
    ???
Return: ???
Notes:    DOS 2.x PRINT.COM does not chain to previous INT 2F handler
    values in AH other than 00h or 01h cause PRINT to return the number of
      files in the queue in AH
SeeAlso: AH=01h
--------P-2F00-------------------------------
INT 2F U - PSPRINT - PRINT JOB CONTROL
    AH = 00h
    ???
Return: ???
--------c-2F0080-----------------------------
INT 2F - DOS 3.1+ PRINT.COM - GIVE PRINT A TIME SLICE
    AX = 0080h
Return: after PRINT executes
Note:    PRINT returns AL=01h if AH=00h but AL is not 80h on entry
--------c-2F01-------------------------------
INT 2F U - DOS 2.x only PRINT.COM - ???
    AH = 01h
    ???
Return: ???
Notes:    DOS 2.x PRINT.COM does not chain to previous INT 2F handler
    values in AH other than 00h or 01h cause PRINT to return the number of
      files in the queue in AH
SeeAlso: AH=00h
--------c-2F0100-----------------------------
INT 2F - DOS 3+ PRINT.COM - INSTALLATION CHECK
    AX = 0100h
Return: AL = status
        00h not installed
        01h not installed, but not OK to install
        FFh installed
SeeAlso: AX=0101h
--------c-2F0100SI20D6-----------------------
INT 2F U - PrintCache 3.1 PRINT.COM - INSTALLATION CHECK
    AX = 0100h
    SI = 20D6h
    DI = 8761h
Return: AX = 00FFh if installed
    DI = 0001h if PrintCache's PRINT.COM installed and magic values match
        SI = resident code segment
Program: PrintCache PRINT.COM is a DOS PRINT replacement included in
      LaserTools' PrintCache memory/disk-based print spooler package
Note:    if either of SI or DI differ from the indicated magic values, only AX
      will be modified on return, for compatibility with DOS PRINT
SeeAlso: AX=0101h/SI=20D6h,AX=C000h"PCACHE"
--------c-2F0101-----------------------------
INT 2F - DOS 3+ PRINT.COM - SUBMIT FILE FOR PRINTING
    AX = 0101h
    DS:DX -> submit packet (see below)
Return: CF clear if successful
        AL = status
        01h added to queue
        9Eh now printing
    CF set on error
        AX = error code (see below, also INT 21/AH=59h)
SeeAlso: AX=0102h

Format of submit packet:
Offset    Size    Description
 00h    BYTE    level (must be 00h)
 01h    DWORD    pointer to ASCIZ filename (no wildcards)

Values for PRINT error code:
 01h invalid function
 02h file not found
 03h path not found
 04h out of file handles
 05h access denied
 08h print queue full
 09h spooler busy
 0Ch name too long
 0Fh invalid drive
--------c-2F0101SI20D6-----------------------
INT 2F U - PrintCache v3.1 PRINT.COM - SUBMIT FILE FOR PRINTING
    AX = 0101h
    SI = 20D6h
    DI = 8761h
    DS:DX -> submit packet (see AX=0101h)
    CL = print options
        bit 4: use default options
Return: CF clear if successful
        AL = status
        01h added to queue
        9Eh now printing
    CF set on error
        AX = error code (see AX=0101h)
Program: PrintCache PRINT.COM is a DOS PRINT replacement included in
      LaserTools' PrintCache memory/disk-based print spooler package
Note:    if either SI or DI differs from the indicated magic values on entry,
      PrintCache will use the default print options for the file for
      compatibility with DOS PRINT
SeeAlso: AX=0100h/SI=20D6h,AX=0101h,AX=0107h"PrintCache"
--------c-2F0102-----------------------------
INT 2F - DOS 3+ PRINT.COM - REMOVE FILE FROM PRINT QUEUE
    AX = 0102h
    DS:DX -> ASCIZ filename (wildcards allowed)
Return: CF clear if successful
    CF set on error
        AX = error code (see AX=0101h)
SeeAlso: AX=0101h,AX=0103h
--------c-2F0103-----------------------------
INT 2F - DOS 3+ PRINT.COM - CANCEL ALL FILES IN PRINT QUEUE
    AX = 0103h
Return: CF clear if successful
    CF set on error
        AX = error code (see AX=0101h)
SeeAlso: AX=0102h
--------c-2F0104-----------------------------
INT 2F - DOS 3+ PRINT.COM - FREEZE PRINT QUEUE TO READ JOB STATUS
    AX = 0104h
Return: CF clear if successful
        DX = error count since status last read
        DS:SI -> print queue
    CF set on error
        AX = error code (see AX=0101h)
Desc:    get the list of print jobs, temporarily suspending PRINT's activities
      to avoid changing the list while it is being examined
Notes:    the print queue is an array of 64-byte ASCIZ filenames terminated by
      an empty filename; the first name is the file currently being printed
    printing is stopped until AX=0105h is called to prevent the queue
      from changing while the filenames are being read
SeeAlso: AX=0101h,AX=0105h
--------c-2F0105-----------------------------
INT 2F - DOS 3+ PRINT.COM - RESTART PRINT QUEUE AFTER STATUS READ
    AX = 0105h
Return: CF clear if successful
    CF set on error
        AX = error code (see AX=0101h)
Desc:    restart PRINT's activities once an application finishes examining the
      print queue
SeeAlso: AX=0104h
--------c-2F0106-----------------------------
INT 2F - DOS 3.3+ PRINT.COM - GET PRINTER DEVICE
    AX = 0106h
Return: CF set if files in print queue
        AX = error code 0008h (queue full)
        DS:SI -> device driver header
    CF clear if print queue empty
        AX = 0000h
Desc:    determine which device, if any, PRINT is currently using for output
Notes:    documented for DOS 5+, but not documented for prior versions
    this function can be used to allow a program to avoid printing to the
      printer on which PRINT is currently performing output
SeeAlso: AX=0104h
--------c-2F0107-----------------------------
INT 2F U - PrintCache v3.1 PRINT.COM - SET TRAILING FORM FEEDS
    AX = 0107h
    CL bit 0: output form feed between print jobs
Return: AL destroyed
SeeAlso: AX=0100h/SI=20D6h,AX=0101h/SI=20D6h
--------N-2F0200-----------------------------
INT 2F U - PC LAN PROGRAM REDIR/REDIRIFS internal - INSTALLATION CHECK
    AX = 0200h
Return: AL = FFh if installed
Desc:    determine whether the PC LAN Program redirector is installed
SeeAlso: AX=0201h,AX=0203h
--------N-2F0201-----------------------------
INT 2F U - PC LAN PROGRAM REDIR/REDIRIFS internal - ???
    AX = 0201h
Return: nothing???
Notes:    this function is called by the DOS 3.3+ PRINT.COM
    AX=0202h appears to be the opposite function
    these functions are supposedly used to signal opening and closing of
      printers
SeeAlso: AX=0202h
--------N-2F0202-----------------------------
INT 2F U - PC LAN PROGRAM REDIR/REDIRIFS internal - ???
    AX = 0202h
    ???
Return: nothing???
Notes:    this function is called by the DOS 3.3+ PRINT.COM
    these functions are supposedly used to signal opening and closing of
      printers
SeeAlso: AX=0201h
--------N-2F0203-----------------------------
INT 2F U - PC LAN PROGRAM REDIR/REDIRIFS internal - ???
    AX = 0203h
Return: nothing???
Notes:    this function is called by the DOS 3.3+ PRINT.COM
    AX=0204h appears to be the opposite function
    these functions are supposedly used to signal opening and closing of
      printers
SeeAlso: AX=0200h,AX=0204h
--------N-2F0204-----------------------------
INT 2F U - PC LAN PROGRAM REDIR/REDIRIFS internal - ???
    AX = 0204h
    ???
Return: nothing???
Notes:    this function is called by the DOS 3.3+ PRINT.COM
    AX=0203h appears to be the opposite function
    these functions are supposedly used to signal opening and closing of
      printers
SeeAlso: AX=0200h,AX=0203h
--------N-2F---------------------------------
INT 2F U - PC LAN PROGRAM REDIR/REDIRIFS internal - ???
    AX = 02xxh
    ???
Return: ???
--------l-2F0500-----------------------------
INT 2F U - DOS 3+ CRITICAL ERROR HANDLER - INSTALLATION CHECK
    AX = 0500h
Return: AL = 00h not installed, OK to install
         01h not installed, can't install
         FFh installed
Desc:    determine whether a critical error message override is installed
Note:    this set of functions allows a user program to partially or completely
      override the default critical error handler's message in COMMAND.COM
SeeAlso: AH=05h,INT 24
--------l-2F05-------------------------------
INT 2F CU - DOS 3+ CRITICAL ERROR HANDLER - EXPAND ERROR INTO STRING
    AH = 05h
---DOS 3.x---
    AL = extended error code (not zero)
---DOS 4+ ---
    AL = error type
        01h DOS extended error code
        02h parameter error
    BX = error code
Return: CF clear if successful
        ES:DI -> ASCIZ error message (read-only)
        AL = completion state
        00h message requires completion with device name, drive, etc.
        01h message is complete as returned
    CF set if error code can't be converted to string
        AX,DI,ES destroyed
    other flags corrupted
Notes:    called at start of COMMAND.COM's default critical error handler if
      installed by a user program, allowing partial or complete overriding
      of the default error messages
    subfunction 02h is called by many DOS 4 external programs
    DR-DOS's COMMAND.COM appends additional info ("0 files copied") to the
      returned string
SeeAlso: AX=0500h,AX=122Eh,INT 24
--------U-2F0600-----------------------------
INT 2F - DOS 3+ ASSIGN - INSTALLATION CHECK
    AX = 0600h
Return: AL = status
        00h not installed
        01h not installed, but not OK to install
        FFh installed
Notes:    ASSIGN is not a TSR in DR-DOS 5.0; it is internally replaced by SUBST
      (see INT 21/AH=52h)
    undocumented prior to the release of DOS 5.0
SeeAlso: AX=0601h,INT 21/AH=52h
--------U-2F0601-----------------------------
INT 2F U - DOS 3+ ASSIGN - GET DRIVE ASSIGNMENT TABLE
    AX = 0601h
Return: ES = segment of ASSIGN work area and assignment table
Note:    under DOS 3+, the 26 bytes starting at ES:0103h specify which drive
      each of A: to Z: is mapped to.  Initially set to 01h 02h 03h....
SeeAlso: AX=0600h
--------D-2F0800-----------------------------
INT 2F U - DRIVER.SYS support - INSTALLATION CHECK
    AX = 0800h
Return: AL = 00h not installed, OK to install
         01h not installed, not OK to install
         FFh installed
Desc:    determine whether the internal support code used by DRIVER.SYS is
      present
Note:    supported by DR-DOS 5.0
--------D-2F0801-----------------------------
INT 2F U - DRIVER.SYS support - ADD NEW BLOCK DEVICE
    AX = 0801h
    DS:DI -> drive data table (see AX=0803h)
Return: AX,BX,SI,ES destroyed
Notes:    moves down internal list of drive data tables, copying and modifying
      the drive description flags word for tables referencing same physical
      drive
    the data table is appended to the chain of tables
    supported by DR-DOS 5.0
SeeAlso: AX=0803h
--------D-2F0802-----------------------------
INT 2F U - DRIVER.SYS support - EXECUTE DEVICE DRIVER REQUEST
    AX = 0802h
    ES:BX -> device driver request header (see below)
Return: request header updated as per requested operation
Notes:    supported by DR-DOS 5.0
    DOS 3.2 executes this function on any AL value from 02h through F7h;
      DOS 4+ executes this function on AL=02h and AL=04h-F7h
    the command codes and structures described below apply to all drivers
      which support the appropriate commands; this call is just one of a
      number of ways in which a device driver request may be invoked
SeeAlso: AX=0800h,AX=0801h,AX=0803h,INT 21/AH=52h,INT 21/AH=99h,INT 21/AH=9Ah

Values for command code:
 00h    INIT
 01h    MEDIA CHECK (block devices)
 02h    BUILD BPB (block devices)
 03h    IOCTL INPUT
 04h    INPUT
 05h    NONDESTRUCTIVE INPUT, NO WAIT (character devices)
 06h    INPUT STATUS (character devices)
 07h    INPUT FLUSH (character devices)
 08h    OUTPUT
 09h    OUTPUT WITH VERIFY
 0Ah    OUTPUT STATUS (character devices)
 0Bh    OUTPUT FLUSH (character devices)
 0Ch    IOCTL OUTPUT
 0Dh    (DOS 3+) DEVICE OPEN
 0Eh    (DOS 3+) DEVICE CLOSE
 0Fh    (DOS 3+) REMOVABLE MEDIA (block devices)
 10h    (DOS 3+) OUTPUT UNTIL BUSY (character devices)
 11h    (European MS-DOS 4.0) STOP OUTPUT (console screen drivers only)
 12h    (European MS-DOS 4.0) RESTART OUTPUT (console screen drivers only)
 13h    (DOS 3.2+) GENERIC IOCTL
 14h    unused
 15h    (European MS-DOS 4.0) RESET UNCERTAIN MEDIA FLAG
 16h    unused
 17h    (DOS 3.2+) GET LOGICAL DEVICE
 18h    (DOS 3.2+) SET LOGICAL DEVICE
 19h    (DOS 5+) CHECK GENERIC IOCTL SUPPORT
 80h    (CD-ROM) READ LONG
 81h    (CD-ROM) reserved
 82h    (CD-ROM) READ LONG PREFETCH
 83h    (CD-ROM) SEEK
 84h    (CD-ROM) PLAY AUDIO
 85h    (CD-ROM) STOP AUDIO
 86h    (CD-ROM) WRITE LONG
 87h    (CD-ROM) WRITE LONG VERIFY
 88h    (CD-ROM) RESUME AUDIO

Format of device driver request header:
Offset    Size    Description
 00h    BYTE    length of request header
 01h    BYTE    subunit within device driver
 02h    BYTE    command code (see above)
 03h    WORD    status (filled in by device driver)
        bit 15: error
        bits 14-11: reserved
        bit 10: ??? set by DOS kernel on entry to some driver calls
        bit 9: busy
        bit 8: done (may be clear on return under European MS-DOS 4.0)
        bits 7-0: error code if bit 15 set (see below)
---DOS---
 05h  4 BYTEs    reserved (unused in DOS 2.x and 3.x)
 09h    DWORD    (European MS-DOS 4.0 only) pointer to next request header in
            device's request queue
        (other versions) reserved (unused in DOS 2.x and 3.x)
---STARLITE architecture---
 05h    DWORD    pointer to next request header
 09h  4 BYTEs    reserved
---command code 00h---
 0Dh    BYTE    (return) number of units
 0Eh    DWORD    (call) pointer to DOS device helper function (see below)
            (European MS-DOS 4.0 only)
        (call) pointer past end of memory available to driver (DOS 5+)
        (return) address of first free byte following driver
 12h    DWORD    (call) pointer to commandline arguments
        (return) pointer to BPB array (block drivers) or
                0000h:0000h (character drivers)
 16h    BYTE    (DOS 3+) drive number for first unit of block driver (0=A)
   ---European MS-DOS 4.0---
 17h    DWORD    pointer to function to save registers on stack
   ---DOS 5+ ---
 17h    WORD    (return) error-message flag
            0001h MS-DOS should display error msg on init failure
---command code 01h---
 0Dh    BYTE    media descriptor
 0Eh    BYTE    returned status
        00h don't know
        01h media has not changed
        FFh media has been changed
 0Fh    DWORD    (return, DOS 3+) pointer to previous volume ID if OPEN/CLOSE/RM
          bit in device header is set and disk changed
---command code 02h---
 0Dh    BYTE    media descriptor
 0Eh    DWORD    transfer address
        -> scratch sector if NON-IBM FORMAT bit in device header set
        -> first FAT sector otherwise
 12h    DWORD    pointer to BPB (set by driver) (see INT 21/AH=53h)
---command codes 03h,0Ch--- (see also INT 21/AX=4402h,INT 21/AX=4403h)
 0Dh    BYTE    media descriptor (block devices only)
 0Eh    DWORD    transfer address
 12h    WORD    (call) number of bytes to read/write
        (return) actual number of bytes read or written
---command codes 04h,08h,09h---
 0Dh    BYTE    media descriptor (block devices only)
 0Eh    DWORD    transfer address
 12h    WORD    byte count (character devices) or sector count (block devices)
 14h    WORD    starting sector number (block devices only)
 16h    DWORD    (DOS 3+) pointer to volume ID if error 0Fh returned
 1Ah    DWORD    (DOS 4+) 32-bit starting sector number (block devices with
        device attribute word bit 1 set only) if starting sector number
        above is FFFFh (see INT 21/AH=52h)
---command code 05h---
 0Dh    BYTE    byte read from device if BUSY bit clear on return
---command codes 06h,07h,0Ah,0Bh,0Dh,0Eh,0Fh---
 no further fields
---command code 10h---
 0Dh    BYTE    unused
 0Eh    DWORD    transfer address
 12h    WORD    (call) number of bytes to write
        (return) actual number of bytes written
---command codes 11h,12h---
 0Dh    BYTE    reserved
---command code 15h---
 no further fields
---command codes 13h,19h---
 0Dh    BYTE    category code
        00h unknown
        01h COMn:
        03h CON
        05h LPTn:
        07h mouse (European MS-DOS 4.0)
        08h disk
        9Eh (STARLITE) Media Access Control driver
 0Eh    BYTE    function code
        00h (STARLITE) MAC Bind request
 0Fh    WORD    copy of DS at time of IOCTL call (apparently unused in DOS 3.3)
        SI contents (European MS-DOS 4.0)
 11h    WORD    offset of device driver header
        DI contents (European MS-DOS 4.0)
 13h    DWORD    pointer to parameter block from INT 21/AX=440Ch or AX=440Dh
---command codes 80h,82h---
 0Dh    BYTE    addressing mode
        00h HSG (default)
        01h Phillips/Sony Red Book
 0Eh    DWORD    transfer address (ignored for command 82h)
 12h    WORD    number of sectors to read
        (if 0 for command 82h, request is an advisory seek)
 14h    DWORD    starting sector number
        logical sector number in HSG mode
        frame/second/minute/unused in Red Book mode
        (HSG sector = minute * 4500 + second * 75 + frame - 150)
 18h    BYTE    data read mode
        00h cooked (2048 bytes per frame)
        01h raw (2352 bytes per frame, including EDC/ECC)
 19h    BYTE    interleave size (number of sectors stored consecutively)
 1Ah    BYTE    interleave skip factor (# sectors between consec portions)
---command code 83h---
 0Dh    BYTE    addressing mode (see above)
 0Eh    DWORD    transfer address (ignored)
 12h    WORD    number of sectors to read (ignored)
 14h    DWORD    starting sector number (see also above)
---command code 84h---
 0Dh    BYTE    addressing mode (see above)
 0Eh    DWORD    starting sector number (see also above)
 12h    DWORD    number of sectors to play
---command codes 85h,88h---
 no further fields
---command codes 86h,87h---
 0Dh    BYTE    addressing mode (see above)
 0Eh    DWORD    transfer address (ignored in write mode 0)
 12h    WORD    number of sectors to write
 14h    DWORD    starting sector number (see also above)
 18h    BYTE    write mode
        00h mode 0 (write all zeros)
        01h mode 1 (default) (2048 bytes per sector)
        02h mode 2 form 1 (2048 bytes per sector)
        03h mode 2 form 2 (2336 bytes per sector)
 19h    BYTE    interleave size (number of sectors stored consecutively)
 1Ah    BYTE    interleave skip factor (# sectors between consec portions)

Values for error code:
 00h    write-protect violation
 01h    unknown unit
 02h    drive not ready
 03h    unknown command
 04h    CRC error
 05h    bad drive request structure length
 06h    seek error
 07h    unknown media
 08h    sector not found
 09h    printer out of paper
 0Ah    write fault
 0Bh    read fault
 0Ch    general failure
 0Dh    reserved
 0Eh    (CD-ROM) media unavailable
 0Fh    invalid disk change

Call European MS-DOS 4.0 device helper function with:
    DL = function
        00h "SchedClock" called on each timer tick
        AL = tick interval in milliseconds
        01h "DevDone" device I/O complete
        ES:BX -> request header
        Note:    must update status word first; may be called from
              an interrupt handler
        02h "PullRequest" pull next request from queue
        DS:SI -> DWORD pointer to start of device's request queue
        Return: ZF clear if pending request
                ES:BX -> request header
            ZF set if no more requests
        03h "PullParticular" remove specific request from queue
        DS:SI -> DWORD pointer to start of device's request queue
        ES:BX -> request header
        Return: ZF set if request header not found
        04h "PushRequest" push the request onto the queue
        DS:SI -> DWORD pointer to start of device's request queue
        ES:BX -> request header
        interrupts disabled
        05h "ConsInputFilter" keyboard input check
        AX = character (high byte 00h if PC ASCII character)
        Return: ZF set if character should be discarded
            ZF clear if character should be handled normally
        Note:    called by keyboard interrupt handler so DOS can scan
              for special input characters
        06h "SortRequest" push request in sorted order by starting sector
        DS:SI -> DWORD pointer to start of device's request queue
        ES:BX -> request header
        interrupts disabled
        07h "SigEvent" send signal on keyboard event
        AH = event identifier
        Return: AL,FLAGS destroyed
        09h "ProcBlock" block on event
        AX:BX = event identifier (typically a pointer)
        CX = timeout in ms or 0000h for never
        DH = interruptable flag (nonzero if pause may be interrupted)
        interrupts disabled
        Return: after corresponding ProcRun call
            CF clear if event wakeup, set if unusual wakeup
            ZF set if timeout wakeup, clear if interrupted
            AL = wakeup code, nonzero if unusual wakeup
            interrupts enabled
            BX,CX,DX destroyed
        Note:    block process and schedules another to run
        0Ah "ProcRun" unblock process
        AX:BX = event identifier (typically a pointer)
        Return: AX = number of processes awakened
            ZF set if no processes awakened
            BX,CX,DX destroyed
        0Bh "QueueInit" initialize/clear character queue
        DS:BX -> character queue structure (see below)
        Note:    the queue size field must be set before calling
        0Dh "QueueWrite" put a character in the queue
        DS:BX -> character queue (see below)
        AL = character to append to end of queue
        Return: ZF set if queue is full
            ZF clear if character stored
        0Eh "QueueRead" get a character from the queue
        DS:BX -> character queue (see below)
        Return: ZF set if queue is empty
            ZF clear if characters in queue
                AL = first character in queue
        10h "GetDOSVar" return pointer to DOS variable
        AL = index of variable
            03h current process ID
        BX = index into variable if AL specifies an array
        CX = expected length of variable
        Return: CF clear if successful
                DX:AX -> variable
            CF set on error
                AX,DX destroyed
            BX,CX destroyed
        Note:    the variables may not be modified
        14h "Yield" yield CPU if higher-priority task ready to run
        Return: FLAGS destroyed
        1Bh "CritEnter" begin system critical section
        DS:BX -> semaphore (6 BYTEs, initialized to zero)
        Return: AX,BX,CX,DX destroyed
        1Ch "CritLeave" end system critical section
        DS:BX -> semaphore (6 BYTEs, initialized to zero)
        Return: AX,BX,CX,DX destroyed
        Note:    must be called in the context of the process which
              called CritEnter on the semaphore
Note:    the DWORD pointing at the request queue must be allocated by the driver
      and initialized to 0000h:0000h.  It always points at the next request
      to be executed

Format of character queue:
Offset    Size    Description
 00h    WORD    size of queue in bytes
 02h    WORD    index of next character out
 04h    WORD    count of characters in the queue
 06h  N BYTEs    queue buffer
--------D-2F0803-----------------------------
INT 2F U - DOS 4+ DRIVER.SYS support - GET DRIVE DATA TABLE LIST
    AX = 0803h
Return: DS:DI -> first drive data table in list
Note:    not available under DR-DOS 5.0
SeeAlso: AX=0801h

Format of DOS 3.30 drive data table:
Offset    Size    Description
 00h    DWORD    pointer to next table (offset FFFFh if last table)
 04h    BYTE    physical unit number (for INT 13)
 05h    BYTE    logical drive number (0=A:)
 06h 19 BYTEs    BIOS Parameter Block (see also INT 21/AH=53h)
        Offset    Size    Description
         00h    WORD    bytes per sector
         02h    BYTE    sectors per cluster, FFh if unknown
         03h    WORD    number of reserved sectors
         05h    BYTE    number of FATs
         06h    WORD    number of root dir entries
         08h    WORD    total sectors
         0Ah    BYTE    media descriptor, 00h if unknown
         0Bh    WORD    sectors per FAT
         0Dh    WORD    sectors per track
         0Fh    WORD    number of heads
         11h    WORD    number of hidden sectors
 19h    BYTE    flags
        bit 6: 16-bit FAT instead of 12-bit FAT
 1Ah    WORD    number of DEVICE OPEN calls without corresponding DEVICE CLOSE
 1Ch 11 BYTEs    volume label or "NO NAME    " if none (always "NO NAME" for
        fixed media)
 27h    BYTE    terminating null for volume label???
 28h    BYTE    device type (see INT 21/AX=440Dh)
 29h    WORD    bit flags describing drive (see below)
 2Bh    WORD    number of cylinders
 2Dh 19 BYTEs    BIOS Parameter Block for highest capacity supported
 40h  3 BYTEs    ???
 43h  9 BYTEs    filesystem type???, default = "NO NAME    "
        (apparently only MS-DOS 3.30 fixed media, nulls for removable
        media and PC-DOS 3.30)
 4Ch    BYTE    least-significant byte of last-accessed cylinder number
---removable media---
 4Dh    DWORD    time of last access in clock ticks (FFFFFFFFh if never)
---fixed media---
 4Dh    WORD    partition (FFFFh = primary, 0001h = extended)
 4Fh    WORD    absolute cylinder number of partition's start on physical
        drive (always FFFFh if primary partition)

Format of COMPAQ DOS 3.31 drive data table:
Offset    Size    Description
 00h    DWORD    pointer to next table (offset FFFFh if last table)
 04h    BYTE    physical unit number (for INT 13)
 05h    BYTE    logical drive number (0=A:)
 06h 25 BYTEs    BIOS Parameter Block (see DOS 4.0-6.0 drive data table below)
 1Fh  6 BYTEs    reserved fields from BPB above???
 25h    BYTE    flags
        bit 6: 16-bit FAT instead of 12-bit FAT
        bit 5: large volume???
 26h    WORD    device-open count???
 28h 11 BYTEs    volume label or "NO NAME    " if none (always "NO NAME" for
        fixed media)
 33h    BYTE    terminating null for volume label
 34h    BYTE    device type (see INT 21/AX=440Dh)
 35h    WORD    bit flags describing drive (see below)
 37h    WORD    number of cylinders
 39h 25 BYTEs    BIOS parameter block for highest capacity drive supports
 52h  6 BYTEs    ??? apparently always zeros
 58h    BYTE    least-significant byte of last-accessed cylinder number
---removable media---
 59h    DWORD    time of last access in clock ticks (FFFFFFFFh if never)
---fixed media---
 59h    WORD    partition (FFFFh = primary, 0001h = extended)
 5Bh    WORD    absolute cylinder number of partition's start on physical
        drive (always FFFFh if primary partition)

Format of DOS 4.0-6.0 drive data table:
Offset    Size    Description
 00h    DWORD    pointer to next table (offset FFFFh if last table)
 04h    BYTE    physical unit number (for INT 13)
 05h    BYTE    logical drive number (0=A:)
 06h 25 BYTEs    BIOS Parameter Block (see also INT 21/AH=53h)
        Offset    Size    Description
         00h    WORD    bytes per sector
         02h    BYTE    sectors per cluster, FFh if unknown
         03h    WORD    number of reserved sectors
         05h    BYTE    number of FATs
         06h    WORD    number of root dir entries
         08h    WORD    total sectors (see offset 15h if zero)
         0Ah    BYTE    media descriptor, 00h if unknown
         0Bh    WORD    sectors per FAT
         0Dh    WORD    sectors per track
         0Fh    WORD    number of heads
         11h    DWORD    number of hidden sectors
         15h    DWORD    total sectors if WORD at 08h is zero
 1Fh    BYTE    flags
        bit 6: 16-bit FAT instead of 12-bit
        bit 7: unsupportable disk (all accesses will return Not Ready)
 20h    WORD    device-open count
 22h    BYTE    device type (see INT 21/AX=440Dh)
 23h    WORD    bit flags describing drive (see below)
 25h    WORD    number of cylinders
 27h 25 BYTEs    BIOS Parameter Block for default (highest) capacity supported
 40h  6 BYTEs    reserved (part of BPB above)
 46h    BYTE    last track accessed
---removable media---
 47h    DWORD    time of last access in clock ticks (FFFFFFFFh if never)
---fixed media---
 47h    WORD    partition (FFFFh = primary, 0001h = extended)
        always 0001h for DOS 5+
 49h    WORD    absolute cylinder number of partition's start on physical drive
        (FFFFh if primary partition in DOS 4.x)
------
 4Bh 11 BYTEs    volume label or "NO NAME    " if none (apparently taken from
        extended boot record rather than root directory)
 56h    BYTE    terminating null for volume label
 57h    DWORD    serial number
 5Bh  8 BYTEs    filesystem type ("FAT12      " or "FAT16    ")
 63h    BYTE    terminating null for filesystem type

Bitfields for flags describing drive:
 bit 0    fixed media
 bit 1    door lock ("changeline") supported
 bit 2    current BPB locked
 bit 3    all sectors in a track are the same size
 bit 4    physical drive has multiple logical units
 bit 5    current logical drive for physical drive
 bit 6    disk change detected
 bit 7    set DASD before formatting
 bit 8    disk reformatted
 bit 9    unformatted (fixed media only, disables reads and writes)
--------f-2F1000-----------------------------
INT 2F - SHARE - INSTALLATION CHECK
    AX = 1000h
Return: AL = 00h  not installed, OK to install
         01h  not installed, not OK to install
         FFh  installed
BUGS:    values of AL other than 00h put DOS 3.x SHARE into an infinite loop
      (08E9: OR  AL,AL
       08EB: JNZ 08EB) <- the buggy instruction (DOS 3.3)
    values of AL other than described here put PC-DOS 4.00 into the same
      loop (the buggy instructions are the same)
Notes:    supported by OS/2 v1.3+ compatibility box, which always returns AL=FFh
    if DOS 4.01 SHARE was automatically loaded, file sharing is in an
      inactive state (due to the undocumented /NC flag used by the autoload
      code) until this call is made
    DOS 5+ chains to the previous handler if AL <> 00h on entry
    Windows Enhanced mode hooks this call and reports that SHARE is
      installed even when it is not
SeeAlso: AX=1080h,INT 21/AH=52h
--------d-2F1001-----------------------------
INT 2F U - DR-DOS 6.0 SHARE internal - SET ???
    AX = 1001h
    DX:BX -> ???function
Note:    this function is also supported by SuperStor, a disk-compression
      program by Addstor which is bundled with DR-DOS 6.0
SeeAlso: AX=1000h,X=F800h
--------f-2F1040-----------------------------
INT 2F U - DOS 4 only SHARE internal - ???
    AX = 1040h
    ???
Return: AL = FFh???
SeeAlso: AX=1000h
--------f-2F1080-----------------------------
INT 2F U - DOS 4 only SHARE internal - TURN ON FILE SHARING CHECKS
    AX = 1080h
Return: AL = status
        F0h successful
        FFh checking was already on
Note:    DOS 4.x SHARE has dual functions: FCB support for large (>32M) media
      and file sharing checks.  The undocumented commandline flag /NC can
      be used to disable the sharing code.
SeeAlso: AX=1000h,AX=1081h
--------f-2F1081-----------------------------
INT 2F U - DOS 4 only SHARE internal - TURN OFF FILE SHARING CHECKS
    AX = 1081h
Return: AL = status
        F0h successful
        FFh checking was already off
Note:    (see AX=1080h)
SeeAlso: AX=1000h,AX=1080h
--------O-2F10FF-----------------------------
INT 2F U - Multiplex - DR-DOS 5.0 - ???
    AX = 10FFh
    ES:BX -> ???
Note:    sets pointer in kernel
--------N-2F1100-----------------------------
INT 2F C - NETWORK REDIRECTOR - INSTALLATION CHECK
    AX = 1100h
Return: AL = status
        00h not installed, OK to install
        01h not installed, not OK to install
        FFh installed
        AH = product identifier (ad hoc by various manufacturers)
            00h if PC Tools v8 DRIVEMAP
            42h ('B') for Beame&Whiteside BWNFS v3.0a
            6Eh ('n') for NetWare Lite v1.1 CLIENT
Notes:    this function is called by the DOS 3.1+ kernel
    in DOS 4.x only, the 11xx calls are all in IFSFUNC.EXE, not in the
      PC LAN Program redirector; DOS 5+ moves the calls back into the
      redirector
    the PC Network 1.00 redirector (renamed to PC LAN Program in 1.1-1.3)
      only supports AL=00h-27h
--------d-2F1100SFDADA-----------------------
INT 2F - MSCDEX (MS CD-ROM Extensions) - INSTALLATION CHECK
    AX = 1100h subfn DADAh
    STACK: WORD DADAh
Return: AL = status
        00h not installed, OK to install
        STACK unchanged
        01h not installed, not OK to install
        STACK unchanged
        FFh installed
        STACK: WORD    ADADh if MSCDEX installed
                DADBh if Lotus CD/Networker installed
Note:    although MSCDEX sets the stack word to ADADh on return, any value other
      than DADAh is considered to mean that MSCDEX is already installed;
      Lotus CD/Networker v4+ uses this feature to fool MSCDEX into
      thinking it is already installed when it is in fact CD/Networker
      that is installed
Index:    installation check;Lotus CD/Networker
Index:    Lotus CD/Networker;installation check
--------N-2F1101-----------------------------
INT 2F CU - NETWORK REDIRECTOR - REMOVE REMOTE DIRECTORY
    AX = 1101h
    SS = DOS DS
    SDA first filename pointer -> fully-qualified directory name
    SDA CDS pointer -> current directory structure for drive with dir
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
Note:    this function is called by the DOS 3.1+ kernel
SeeAlso: AX=1103h,AX=1105h,INT 21/AH=3Ah,INT 21/AH=60h
--------N-2F1102-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - REMOVE REMOTE DIRECTORY
    AX = 1102h
    SS = DOS DS
    SDA first filename pointer -> fully-qualified directory name
    SDA CDS pointer -> current directory structure for drive with dir
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
Note:    appears to be identical to AX=1101h; MS internal documentation calls
      this function "SEQ_RMDIR"
SeeAlso: AX=1101h
--------N-2F1103-----------------------------
INT 2F CU - NETWORK REDIRECTOR - MAKE REMOTE DIRECTORY
    AX = 1103h
    SS = DOS DS
    SDA first filename pointer -> fully-qualified directory name
    SDA CDS pointer -> current directory structure for drive with dir
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
Note:    this function is called by the DOS 3.1+ kernel
SeeAlso: AX=1101h,AX=1105h,INT 21/AH=39h,INT 21/AH=60h
--------N-2F1104-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - MAKE REMOTE DIRECTORY
    AX = 1104h
    SS = DOS DS
    SDA first filename pointer -> fully-qualified directory name
    SDA CDS pointer -> current directory structure for drive with dir
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
Note:    appears to be identical to AX=1103h
SeeAlso: AX=1103h
--------N-2F1105-----------------------------
INT 2F CU - NETWORK REDIRECTOR - CHDIR
    AX = 1105h
    SS = DOS DS
    SDA first filename pointer -> fully-qualified directory name
    SDA CDS pointer -> current directory structure for drive with dir
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
        CDS updated with new path
Notes:    this function is called by the DOS 3.1+ kernel
    directory string in CDS should not have a terminating backslash unless
      the current directory is the root
SeeAlso: AX=1101h,AX=1103h,INT 21/AH=3Bh,INT 21/AH=60h
--------N-2F1106-----------------------------
INT 2F CU - NETWORK REDIRECTOR - CLOSE REMOTE FILE
    AX = 1106h
    BX = device info word from SFT
    ES:DI -> SFT
        SFT DPB field -> DPB of drive containing file
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
        SFT updated (redirector must decrement open count, which may be
            done with INT 2F/AX=1208h)
Note:    this function is called by the DOS 3.1+ kernel
SeeAlso: AX=1116h,AX=1201h,AX=1208h,AX=1227h,INT 21/AH=3Eh
--------N-2F1107-----------------------------
INT 2F CU - NETWORK REDIRECTOR - COMMIT REMOTE FILE
    AX = 1107h
    ES:DI -> SFT
        SFT DPB field -> DPB of drive containing file
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
        all buffers for file flushed
        directory entry updated
Note:    this function is called by the DOS 3.1+ kernel
SeeAlso: INT 21/AH=68h,INT 21/AX=5D01h
--------N-2F1108-----------------------------
INT 2F CU - NETWORK REDIRECTOR - READ FROM REMOTE FILE
    AX = 1108h
    ES:DI -> SFT
        SFT DPB field -> DPB of drive containing file
    CX = number of bytes
    SS = DOS DS
    SDA DTA field -> user buffer
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
        CX = number of bytes read (0000h = end of file)
        SFT updated
Note:    this function is called by the DOS 3.1+ kernel
SeeAlso: AX=1109h,AX=1229h,INT 21/AH=3Fh,INT 21/AX=5D06h
--------N-2F1109-----------------------------
INT 2F CU - NETWORK REDIRECTOR - WRITE TO REMOTE FILE
    AX = 1109h
    ES:DI -> SFT
        SFT DPB field -> DPB of drive containing file
    CX = number of bytes
    SS = DOS DS
    SDA DTA field -> user buffer
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
        CX = number of bytes written
        SFT updated
Notes:    this function is called by the DOS 3.1+ kernel
    PrintCache v3.1 PCACHE.EXE intercepts this function for SFTs where
      the Device Driver Header field points at PCACHE, but does not
      intercept any other network redirector functions
SeeAlso: AX=1107h,AX=1108h,INT 21/AH=40h,INT 21/AX=5D06h
--------N-2F110A-----------------------------
INT 2F CU - NETWORK REDIRECTOR (DOS 3.x only) - LOCK REGION OF FILE
    AX = 110Ah
    BX = file handle
    CX:DX = starting offset
    SI = high word of size
    STACK: WORD low word of size
    ES:DI -> SFT
        SFT DPB field -> DPB of drive containing file
    SS = DOS DS
Return: CF set on error
       AL = DOS error code (see INT 21/AH=59h)
    STACK unchanged
Notes:    this function is called by the DOS 3.10-3.31 kernel
    the redirector is expected to resolve lock conflicts
SeeAlso: AX=110Bh,INT 21/AH=5Ch
--------N-2F110A-----------------------------
INT 2F CU - NETWORK REDIRECTOR (DOS 4+) - LOCK/UNLOCK REGION OF FILE
    AX = 110Ah
    BL = function
        00h lock
        01h unlock
    CX = number of lock/unlock parameters (0001h for DOS 4.0-6.1)
    DS:DX -> parameter block (see below)
    ES:DI -> SFT
        SFT DPB field -> DPB of drive containing file
    SS = DOS DS
Return: CF set on error
       AL = DOS error code (see INT 21/AH=59h)
Notes:    this function is called by the DOS 4.0+ kernel
    the redirector is expected to resolve lock conflicts
SeeAlso: AX=110Bh,INT 21/AH=5Ch

Format of parameter block entry [array, but currently limited to single entry]:
Offset    Size    Description
 00h    DWORD    start offset
 04h    DWORD    size of region
--------N-2F110B-----------------------------
INT 2F CU - NETWORK REDIRECTOR (DOS 3.x only) - UNLOCK REGION OF FILE
    AX = 110Bh
    BX = file handle
    CX:DX = starting offset
    SI = high word of size
    STACK: WORD low word of size
    ES:DI -> SFT for file
        SFT DPB field -> DPB of drive containing file
Return: CF set on error
       AL = DOS error code (see INT 21/AH=59h)
    STACK unchanged
Note:    this function is called by the DOS 3.1-3.31 kernel; DOS 4.0+ calls AX=110Ah instead
SeeAlso: AX=110Ah,INT 21/AH=5Ch
--------N-2F110C-----------------------------
INT 2F CU - NETWORK REDIRECTOR - GET DISK INFORMATION
    AX = 110Ch
    ES:DI -> current directory structure for desired drive
Return: AL = sectors per cluster
    AH = media ID byte
    BX = total clusters
    CX = bytes per sector
    DX = number of available clusters
Note:    this function is called by the DOS 3.1+ kernel
SeeAlso: INT 21/AH=36h
--------N-2F110D-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - SET REMOTE FILE'S ATTRIBUTES
    AX = 110Dh
    SDA first filename pointer -> name of file
    ???
Return: ???
Note:    similar to AX=110Eh
SeeAlso: AX=110Eh
--------N-2F110E-----------------------------
INT 2F CU - NETWORK REDIRECTOR - SET REMOTE FILE'S ATTRIBUTES
    AX = 110Eh
    SS = DOS DS
    SDA first filename pointer -> fully-qualified name of file
    SDA CDS pointer -> current directory structure for drive with file
    STACK: WORD new file attributes
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
    STACK unchanged
Note:    this function is called by the DOS 3.1+ kernel
SeeAlso: AX=110Dh,AX=110Fh,INT 21/AX=4301h,INT 21/AH=60h
--------N-2F110F-----------------------------
INT 2F CU - NETWORK REDIRECTOR - GET REMOTE FILE'S ATTRIBUTES AND SIZE
    AX = 110Fh
    SS = DOS DS
    SDA first filename pointer -> fully-qualified name of file
    SDA CDS pointer -> current directory structure for drive with file
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
        AX = file attributes
        BX:DI = file size
Note:    this function is called by the DOS 3.1+ kernel
SeeAlso: AX=110Eh,INT 21/AX=4300h,INT 21/AH=60h
--------N-2F1110-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - GET REMOTE FILE'S ATTRIBUTES AND SIZE
    AX = 1110h
    SDA first filename pointer -> name of file
    ???
Return: ???
Note:    appears to be similar to AX=110Fh
SeeAlso: AX=110Eh
--------N-2F1111-----------------------------
INT 2F CU - NETWORK REDIRECTOR - RENAME REMOTE FILE
    AX = 1111h
    SS = DS = DOS DS
    SDA first filename pointer = offset of fully-qualified old name
    SDA second filename pointer = offset of fully-qualified new name
    SDA CDS pointer -> current directory structure for drive with file
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
Note:    this function is called by the DOS 3.1+ kernel
SeeAlso: AX=1112h,INT 21/AH=56h,INT 21/AH=60h
--------N-2F1112-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - RENAME REMOTE FILE
    AX = 1112h
    SS = DS = DOS DS
    SDA first filename pointer -> name of file
    ???
Return: ???
Note:    similar to AX=1111h
SeeAlso: AX=1111h
--------N-2F1113-----------------------------
INT 2F CU - NETWORK REDIRECTOR - DELETE REMOTE FILE
    AX = 1113h
    SS = DS = DOS DS
    SDA first filename pointer -> fully-qualified filename in DOS DS
    SDA CDS pointer -> current directory structure for drive with file
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
Notes:    this function is called by the DOS 3.1+ kernel
    the filespec may contain wildcards
SeeAlso: AX=1114h,INT 21/AH=41h,INT 21/AH=60h
--------N-2F1114-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - DELETE REMOTE FILE
    AX = 1114h
    SDA first filename pointer -> name of file
    ???
Return: ???
Note:    similar to AX=1113h
SeeAlso: AX=1113h
--------N-2F1115-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - OPEN REMOTE FILE
    AX = 1115h
    SS = DOS DS
    ES:DI -> SFT ???
    ???
Return: ???
Note:    similar to AX=1116h
SeeAlso: AX=1116h,AX=112Eh
--------N-2F1116-----------------------------
INT 2F CU - NETWORK REDIRECTOR - OPEN EXISTING REMOTE FILE
    AX = 1116h
    ES:DI -> uninitialized SFT
    SS = DOS DS
    SDA first filename pointer -> fully-qualified name of file to open
    STACK: WORD file access and sharing modes (see INT 21/AH=3Dh)
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
        SFT filled (except handle count, which DOS manages itself)
    STACK unchanged
Note:    this function is called by the DOS 3.1+ kernel
SeeAlso: AX=1106h,AX=1115h,AX=1117h,AX=1118h,AX=112Eh,INT 21/AH=3Dh
SeeAlso: INT 21/AH=60h
--------N-2F1117-----------------------------
INT 2F CU - NETWORK REDIRECTOR - CREATE/TRUNCATE REMOTE FILE
    AX = 1117h
    ES:DI -> uninitialized SFT
    SS = DOS DS
    SDA first filename pointer -> fully-qualified name of file to open
    SDA CDS pointer -> current directory structure for drive with file
    STACK: WORD file creation mode
            low byte = file attributes (see INT 21/AH=3Ch)
            high byte = 00h normal create, 01h create new file
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
        SFT filled (except handle count, which DOS manages itself)
    STACK unchanged
Note:    this function is called by the DOS 3.1+ kernel
SeeAlso: AX=1106h,AX=1116h,AX=1118h,AX=112Eh,INT 21/AH=3Ch,INT 21/AH=60h
--------N-2F1118-----------------------------
INT 2F CU - NETWORK REDIRECTOR - CREATE/TRUNCATE FILE WITHOUT CDS
    AX = 1118h
    ES:DI -> uninitialized SFT
    SS = DOS DS
    SDA first filename pointer -> fully-qualified name of file
    STACK: WORD file creation mode
            low byte = file attributes
            high byte = 00h normal create, 01h create new file
Return: ???
    STACK unchanged
Note:    this function is called by the DOS 3.1+ kernel when creating a file on a drive for which the
      SDA CDS pointer has offset FFFFh
SeeAlso: AX=1106h,AX=1116h,AX=1117h,AX=112Eh,INT 21/AH=60h
--------N-2F1119-----------------------------
INT 2F CU - NETWORK REDIRECTOR - FIND FIRST FILE WITHOUT CDS
    AX = 1119h
    SS = DS = DOS DS
    [DTA] = uninitialized 21-byte findfirst search data (see INT 21/AH=4Eh)
    SDA first filename pointer -> fully-qualified search template
    SDA search attribute = attribute mask for search
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
        [DTA] = updated findfirst search data
            (bit 7 of first byte must be set)
        [DTA+15h] = standard directory entry for file
Notes:    this function is called by the DOS 3.1+ kernel
    DOS 4.x IFSFUNC returns CF set, AX=0003h
SeeAlso: AX=111Ah,AX=111Bh
--------N-2F111A-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - FIND NEXT FILE WITHOUT CDS
    AX = 111Ah
    ???
Return: CF set
        AX = error code (03h for DOS 4.01 IFSFUNC)
Note:    use AX=111Ch for DOS 5+
SeeAlso: AX=1119h,AX=111Ch
--------N-2F111B-----------------------------
INT 2F CU - NETWORK REDIRECTOR - FINDFIRST
    AX = 111Bh
    SS = DS = DOS DS
    [DTA] = uninitialized 21-byte findfirst search data (see INT 21/AH=4Eh)
    SDA first filename pointer -> fully-qualified search template
    SDA CDS pointer -> current directory structure for drive with file
    SDA search attribute = attribute mask for search
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
        [DTA] = updated findfirst search data
            (bit 7 of first byte must be set)
        [DTA+15h] = standard directory entry for file
Note:    this function is called by the DOS 3.1+ kernel
SeeAlso: AX=1119h,AX=111Ch,INT 21/AH=4Eh,INT 21/AH=60h
--------N-2F111C-----------------------------
INT 2F CU - NETWORK REDIRECTOR - FINDNEXT
    AX = 111Ch
    SS = DS = DOS DS
    ES:DI -> CDS
    [DTA] = 21-byte findfirst search data (see INT 21/AH=4Eh)
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
        [DTA] = updated findfirst search data
            (bit 7 of first byte must be set)
        [DTA+15h] = standard directory entry for file
Note:    this function is called by the DOS 3.1+ kernel
SeeAlso: AX=1119h,AX=111Bh,INT 21/AH=4Fh
--------N-2F111D-----------------------------
INT 2F CU - NETWORK REDIRECTOR - CLOSE ALL REMOTE FILES FOR PROCESS (ABORT)
    AX = 111Dh
    SS = DOS DS
    SDA PSP segment field = PSP of terminating process
Return: nothing
Notes:    used when a process is aborted; the process being terminated is
      indicated by the "sharing PSP" field in the SDA (offset 1Ah/1Ch)
    this function is called by the DOS 3.1+ kernel
    closes all FCBs opened by process
SeeAlso: INT 21/AX=5D04h
--------N-2F111E-----------------------------
INT 2F CU - NETWORK REDIRECTOR - DO REDIRECTION
    AX = 111Eh
    SS = DOS DS
    STACK: WORD function to execute
        5F00h  get redirection mode
            BL = type (03h printer, 04h disk)
            Return: BH = state (00h off, 01h on)
        5F01h  set redirection mode
            BL = type (03h printer, 04h disk)
            BH = state (00h off, 01h on)
        5F02h  get redirection list entry
            BX = redirection list index
            DS:SI -> 16-byte local device name buffer
            ES:DI -> 128-byte network name buffer
            Return: must set user's BX to device type and CX to
                stored parameter value, using AX=1218h to get
                stack frame address
        5F03h  redirect device
            BL = device type (see INT 21/AX=5F03h)
            CX = stored parameter value
            DS:SI -> ASCIZ source device name
            ES:DI -> destination ASCIZ network path + ASCIZ passwd
        5F04h  cancel redirection
            DS:SI -> ASCIZ device name or network path
        5F05h  get redirection list extended entry
            BX = redirection list index
            DS:SI -> buffer for ASCIZ source device name
            ES:DI -> buffer for destination ASCIZ network path
            Return: BH = status flag
                BL = type (03h printer, 04h disk)
                CX = stored parameter value
                BP = NETBIOS local session number
        5F06h  similar to 5F05h???
Return: CF set on error
        AX = error code (see INT 21/AH=59h)
    STACK unchanged
Notes:    this function is called by the DOS 3.1+ kernel on INT 21/AH=5Fh
      (including LAN Manager calls)
    the PC Network 1.00 redirector does not support function 5F06h
SeeAlso: INT 21/AX=5F00h,INT 21/AX=5F01h,INT 21/AX=5F02h,INT 21/AX=5F03h
SeeAlso: INT 21/AX=5F04h,INT 21/AX=5F05h,INT 21/AX=5F06h
--------N-2F111F-----------------------------
INT 2F CU - NETWORK REDIRECTOR - PRINTER SETUP
    AX = 111Fh
    STACK: WORD function
        5E02h  set printer setup
        5E03h  get printer setup
        5E04h  set printer mode
        5E05h  get printer mode
Return: CF set on error
        AX = error code (see INT 21/AH=59h)
    STACK unchanged
Note:    this function is called by the DOS 3.1+ kernel
SeeAlso: INT 21/AX=5E02h,INT 21/AX=5E03h,INT 21/AX=5E04h,INT 21/AX=5E05h
--------N-2F1120-----------------------------
INT 2F CU - NETWORK REDIRECTOR - FLUSH ALL DISK BUFFERS
    AX = 1120h
    DS = DOS DS
    ???
Return: CF clear (successful)
Notes:    this function is called by the DOS 3.1+ kernel
    uses CDS array pointer and LASTDRIVE= entries in DOS list of lists
SeeAlso: INT 21/AH=0Dh,INT 21/AX=5D01h
--------N-2F1121-----------------------------
INT 2F CU - NETWORK REDIRECTOR - SEEK FROM END OF REMOTE FILE
    AX = 1121h
    CX:DX = offset (in bytes) from end
    ES:DI -> SFT
        SFT DPB field -> DPB of drive with file
    SS = DOS DS
Return: CF set on error
        AL = DOS error code (see INT 21/AH=59h)
    CF clear if successful
        DX:AX = new file position
Note:    this function is called by the DOS 3.1+ kernel, but only when seeking
      from the end of a file opened with sharing modes set in such a
      manner that another process is able to change the size of the file
      while it is already open
SeeAlso: AX=1228h,INT 21/AH=42h
--------N-2F1122-----------------------------
INT 2F CU - NETWORK REDIRECTOR - PROCESS TERMINATION HOOK
    AX = 1122h
    SS = DOS DS
    DS = PSP of process about to terminate
Return: ???
Note:    this function is called by the DOS 3.1+ kernel
--------N-2F1123-----------------------------
INT 2F CU - NETWORK REDIRECTOR - QUALIFY REMOTE FILENAME
    AX = 1123h
    DS:SI -> ASCIZ filename to canonicalize
    ES:DI -> 128-byte buffer for qualified name
Return: CF set if not resolved
Notes:    called by MS-DOS 3.1+ kernel, but not called by DR-DOS 5.0 unless the
      filename matches the name of a character device
    called first when DOS attempts to resolve a filename (unless inside an
      AX=5D00h server call); if this fails, DOS resolves the name locally
SeeAlso: AX=1221h,INT 21/AH=60h
--------N-2F1124-----------------------------
INT 2F CU - NETWORK REDIRECTOR - TURN OFF REMOTE PRINTER
    AX = 1124h
    ES:DI -> SFT
    SS = DOS DS
    ???
Return: CX = ???
Note:    this function is called by the DOS 3.1+ kernel if AX=1126h returns CF set
SeeAlso: AX=1126h
--------N-2F1125-----------------------------
INT 2F CU - NETWORK REDIRECTOR - REDIRECTED PRINTER MODE
    AX = 1125h
    STACK: WORD subfunction
        5D07h get print stream state
            Return: DL = current state
        5D08h set print stream state
            DL = new state
        5D09h finish print job
Return: CF set on error
        AX = error code (see INT 21/AH=59h)
    STACK unchanged
Note:    this function is called by the DOS 3.1+ kernel
SeeAlso: INT 21/AX=5D07h,INT 21/AX=5D08h,INT 21/AX=5D09h
--------N-2F1126-----------------------------
INT 2F CU - NETWORK REDIRECTOR - REMOTE PRINTER ECHO ON/OFF
    AX = 1126h
    ES:DI -> SFT for file handle 4???
    SS = DOS DS???
    ???
Return: CF set on error
Notes:    this function is called by the DOS 3.1+ kernel
    called when print echoing (^P, ^PrtSc) changes state and STDPRN has
      bit 11 of the device information word in the SFT set
SeeAlso: AX=1124h
--------N-2F1127-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - UNUSED
    AX = 1127h
Return: CF set
        AX = 0001h (invalid function) (see INT 21/AH=59h)
--------N-2F1128-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - UNUSED
    AX = 1128h
Return: CF set
        AX = 0001h (invalid function) (see INT 21/AH=59h)
--------N-2F1129-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - UNUSED
    AX = 1129h
Return: CF set
        AX = 0001h (invalid function) (see INT 21/AH=59h)
--------N-2F112A-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - CLOSE ALL FILES FOR PROCESS
    AX = 112Ah
    DS = DOS DS
    ???
Return: ???
Note:    does something to each IFS driver
--------N-2F112B-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - GENERIC IOCTL
    AX = 112Bh
    SS = DOS DS
    CX = function/category
    DS:DX -> parameter block
    STACK: WORD value of AX on entry to INT 21 (440Ch or 440Dh)
    ???
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
Note:    this function is called by the DOS 4.0 kernel
--------N-2F112C-----------------------------
INT 2F CU - NETWORK REDIRECTOR (DOS 4+) - "UPDATE_CB" - ???
    AX = 112Ch
    SS = DOS DS
    SDA current SFT pointer -> SFT for file
    ???
Return: CF set on error
Note:    called by SHARE in DOS 5.0-6.0
--------N-2F112D-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - EXTENDED ATTRIBUTES
    AX = 112Dh
    BL = subfunction (value of AL on INT 21)
        02h get extended attributes
        03h get extended attribute properties
        04h set extended attributes
        Return: CF clear
        else ???
        Return: CX = ??? (00h or 02h for DOS 4.01)
    ES:DI -> SFT for file
    SS = DOS DS
Return: DS = DOS DS
Note:    this function is called by the DOS 4.0 kernel on INT 21/AX=5702h,
      INT 21/AX=5703h, and INT 21/AX=5704h
SeeAlso: INT 21/AX=5702h,INT 21/AX=5703h,INT 21/AX=5704h,INT 21/AH=6Eh
--------N-2F112E-----------------------------
INT 2F CU - NETWORK REDIRECTOR (DOS 4+) - EXTENDED OPEN/CREATE FILE
    AX = 112Eh
    SS = DS = DOS DS
    ES:DI -> uninitialized SFT for file
    STACK: WORD file attribute for created/truncated file
            low byte = file attributes
            high byte = 00h normal create/open, 01h create new file
    SDA first filename pointer -> fully-qualified filename
    SDA extended file open action = action code (see INT 21/AX=6C00h)
    SDA extended file open mode = open mode for file (see INT 21/AX=6C00h)
Return: CF set on error
        AX = error code
    CF clear if successful
        CX = result code
        01h file opened
        02h file created
        03h file replaced (truncated)
        SFT initialized (except handle count, which DOS manages itself)
Note:    this function is called by the DOS 4+ kernel
SeeAlso: AX=1115h,AX=1116h,AX=1117h,INT 21/AX=6C00h
--------N-2F112F-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - IFS IOCTL
    AX = 112Fh
    SS = DOS DS
    STACK: WORD function in low byte
        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 = DOS error code (see INT 21/AH=59h)
    CF clear if successful
Note:    this function is called by the DOS 4.0 kernel
SeeAlso: INT 21/AH=6Bh
--------N-2F1130-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - GET IFSFUNC SEGMENT
    AX = 1130h
Return: ES = CS of resident IFSFUNC
--------N-2F1180-----------------------------
INT 2F - LAN Manager Enhanced DOS Services - ???
    AX = 1180h
    ???
Return: ???
--------N-2F1182-----------------------------
INT 2F - LAN Manager Enhanced DOS Services - INSTALL SERVICE
    AX = 1182h
    ???
Return: ???
--------N-2F1184-----------------------------
INT 2F - LAN Manager Enhanced DOS - ???
    AX = 1184h
    ???
Return: ???
--------N-2F1186-----------------------------
INT 2F - LAN Manager Enhanced DOS - DosReadAsynchNmPipe
    AX = 1186h
    DS:SI -> stack frame (see below)
Return: CF clear if successful
    CF set if error
        AX = error code
Note:    LAN Manager enhance mode adds features beyond the standard redirector
      file/printer services
SeeAlso: AX=118Fh,AX=1190h,AX=1191h,INT 21/AX=5F39h

Format of DosReadAsynchNmPipe stack frame:
Offset    Size    Description
 00h    DWORD    -> number of bytes read
 04h    WORD    size of buffer
 06h    DWORD    -> buffer
 0Ah    DWORD    -> return code
 0Eh    DWORD    function to call on completion as function( char far *buffer )
 12h    WORD    handle
--------N-2F118A-----------------------------
INT 2F - LAN Manager 2.0+ DOS Enhanced ENCRYPT.EXE - STREAM ENCRYPTION SERVICE
    AX = 118Ah
    BX = function (0000h or 0001h)
Return: CF clear if successful
        AX = 1100h success
    CF set if error
        AX = 0001h, etc.
SeeAlso: AX=1186h,AH=41h,AH=42h,AH=4Bh
--------N-2F118B-----------------------------
INT 2F - LAN Manager Enhanced DOS - ???
    AX = 118Bh
    ???
Return: ???
--------N-2F118C-----------------------------
INT 2F - LAN Manager Enhanced DOS - ???
    AX = 118Ch
    ???
Return: ???
--------N-2F118E-----------------------------
INT 2F - LAN Manager Enhanced DOS - ???
    AX = 118Eh
    ???
Return: ???
--------N-2F118F-----------------------------
INT 2F - LAN Manager Enhanced DOS - DosWriteAsynchNmPipe
    AX = 118Fh
    DS:SI -> stack frame (see below)
Return: CF clear if successful
    CF set if error
        AX = error code
SeeAlso: AX=1186h,AX=1191h,INT 21/AX=5F3Ah

Format of DosReadAsynchNmPipe stack frame:
Offset    Size    Description
 00h    DWORD    -> number of bytes read
 04h    WORD    Size of buffer
 06h    DWORD    -> buffer
 0Ah    DWORD    -> return code
 0Eh    DWORD    function to call on completion as function( char far *buffer )
 12h    WORD    handle
--------N-2F1190-----------------------------
INT 2F - LAN Manager Enhanced DOS - DosReadAsynchNmPipe2
    AX = 1190h
    DS:SI -> stack frame
Return: CF clear if successful
    CF set if error
        AX = error code
SeeAlso: AX=1186h,AX=1191h

Format of DosReadAsynchNmPipe2 stack frame:
Offset    Size    Description
 00h    DWORD    -> number of bytes read
 04h    WORD    size of buffer
 06h    DWORD    -> buffer
 0Ah    DWORD    -> return code
 0Eh    DWORD    function to call on completion as function( char far *buffer )
 12h    WORD    handle
 14h    DWORD    ???
--------N-2F1191-----------------------------
INT 2F - LAN Manager Enhanced DOS - DosWriteAsynchNmPipe2
    AX = 1191h
    DS:SI -> stack frame (see below)
Return: CF clear if successful
    CF set if error
        AX = error code
SeeAlso: AX=118Fh,AX=1190h,INT 21/AX=5F3Ah

Format of DosReadAsynchNmPipe2 stack frame:
Offset    Size    Description
 00h    DWORD    -> number of bytes read
 04h    WORD    size of buffer
 06h    DWORD    -> buffer
 0Ah    DWORD    -> return code
 0Eh    DWORD    function to call on completion as function( char far *buffer )
 12h    WORD    handle
 14h    DWORD    ???
--------D-2F1200-----------------------------
INT 2F U - DOS 3+ internal - INSTALLATION CHECK
    AX = 1200h
Return: AL = FFh (for compatibility with other INT 2F functions)
--------D-2F1201-----------------------------
INT 2F U - DOS 3+ internal - CLOSE CURRENT FILE
    AX = 1201h
    SS = DOS DS (must be using a DOS internal stack)
    SDA current SFT pointer -> SFT of file to close
Return: CF set on error
    BX???
    CX new reference count of SFT
    ES:DI -> SFT for file
SeeAlso: AX=1106h,AX=1227h,INT 21/AH=3Eh
--------D-2F1202-----------------------------
INT 2F U - DOS 3+ internal - GET INTERRUPT ADDRESS
    AX = 1202h
    STACK: WORD vector number
Return: ES:BX -> interrupt vector
    STACK unchanged
--------D-2F1203-----------------------------
INT 2F U - DOS 3+ internal - GET DOS DATA SEGMENT
    AX = 1203h
Return: DS = data segment of IBMDOS.COM/MSDOS.SYS
Note:    for DOS prior to version 5.0, the data segment is the same as the code
      segment
--------D-2F1204-----------------------------
INT 2F U - DOS 3+ internal - NORMALIZE PATH SEPARATOR
    AX = 1204h
    STACK: WORD character to normalize
Return: AL = normalized character (forward slash turned to backslash, all
        others unchanged)
    ZF set if path separator
    STACK unchanged
--------D-2F1205-----------------------------
INT 2F U - DOS 3+ internal - OUTPUT CHARACTER TO STANDARD OUTPUT
    AX = 1205h
    STACK: WORD character to output
Return: STACK unchanged
Note:    can be called only from within DOS
--------D-2F1206-----------------------------
INT 2F U - DOS 3+ internal - INVOKE CRITICAL ERROR
    AX = 1206h
    DI = error code
    BP:SI -> device driver header
    SS = DOS DS (must be using a DOS internal stack)
    STACK: WORD value to be passed to INT 24 in AX
Return: AL = 0-3 for Abort, Retry, Ignore, Fail
    STACK unchanged
SeeAlso: INT 24
--------D-2F1207-----------------------------
INT 2F U - DOS 3+ internal - MAKE DISK BUFFER MOST-RECENTLY USED
    AX = 1207h
    DS:DI -> disk buffer
Return: nothing
Desc:    move the indicated buffer to the end of the disk buffer chain (least-
      recently used is first); under DOS 3.3, the buffer is then moved to
      the start of the disk buffer chain if it was marked unused
Notes:    can be called only from within DOS
    this function is nearly the same as AX=120Fh
SeeAlso: AX=120Fh
--------D-2F1208-----------------------------
INT 2F U - DOS 3+ internal - DECREMENT SFT REFERENCE COUNT
    AX = 1208h
    ES:DI -> SFT
Return: AX = original value of reference count
Notes:    if the reference count was 1, it is set to FFFFh (since 0 indicates
      that the SFT is not in use).    It is the caller's responsibility to
      set the reference count to zero after cleaning up.
    used by network redirectors such as MSCDEX
SeeAlso: AX=1106h
--------D-2F1209-----------------------------
INT 2F U - DOS 3+ internal - FLUSH AND FREE DISK BUFFER
    AX = 1209h
    DS:DI -> disk buffer
Return: disk buffer marked unused, contents written to disk if buffer dirty
Note:    can be called only from within DOS
SeeAlso: AX=120Eh,AX=1215h
--------D-2F120A-----------------------------
INT 2F U - DOS 3+ internal - PERFORM CRITICAL ERROR INTERRUPT
    AX = 120Ah
    DS = SS = DOS DS (must be using a DOS internal stack)
    STACK: WORD extended error code
Return: AL = user response (0=ignore, 1=retry, 2=abort, 3=fail)
    CF clear if retry, set otherwise
    STACK unchanged
Notes:    can only be called during a DOS function call, as it uses various
      fields in the SDA to set up the registers for the INT 24
    reportedly sets current DPB's first root directory sector to 1
SeeAlso: INT 24
--------D-2F120B-----------------------------
INT 2F U - DOS 3+ internal - SIGNAL SHARING VIOLATION TO USER
    AX = 120Bh
    ES:DI -> system file table entry for previous open of file
    STACK: WORD extended error code (should be 20h--sharing violation)
Return: CF clear if operation should be retried
    CF set if operation should not be retried
        AX = error code (20h) (see INT 21/AH=59h)
    STACK unchanged
Notes:    can only be called during a DOS function call
    should only be called if an attempt was made to open an already-open
      file contrary to the sharing rules
    invokes INT 24 if SFT file opened via FCB or in compatibility mode with
      inheritance allowed
--------D-2F120C-----------------------------
INT 2F U - DOS 3+ internal - OPEN DEVICE AND SET SFT OWNER/MODE
    AX = 120Ch
    SDA current SFT pointer -> SFT for file
    DS = DOS DS
    SS = DOS DS (must be using a DOS internal stack)
Return: ES, DI, AX destroyed
Notes:    invokes "device open" call on device driver for SFT
    changes owner of last-accessed SFT to calling process if it was opened
      via FCB
    called by network redirectors such as MSCDEX
--------D-2F120D-----------------------------
INT 2F U - DOS 3+ internal - GET DATE AND TIME
    AX = 120Dh
    SS = DOS DS (must be using a DOS internal stack)
Return: AX = current date in packed format (see INT 21/AX=5700h)
    DX = current time in packed format (see INT 21/AX=5700h)
SeeAlso: INT 21/AH=2Ah,INT 21/AH=2Ch
--------D-2F120E-----------------------------
INT 2F U - DOS 3+ internal - MARK ALL DISK BUFFERS UNREFERENCED
    AX = 120Eh
    SS = DOS DS (must be using a DOS internal stack)
Return: DS:DI -> first disk buffer
Notes:    clears "referenced" flag on all disk buffers
    in DOS 5+, this has become essentially a NOP, invoking the same code
      used by AX=1224h (SHARING DELAY)
SeeAlso: AX=1209h,AX=1210h,INT 21/AH=0Dh
--------D-2F120F-----------------------------
INT 2F U - DOS 3+ internal - MAKE BUFFER MOST RECENTLY USED
    AX = 120Fh
    DS:DI -> disk buffer
    SS = DOS DS (must be using a DOS internal stack)
Return: DS:DI -> next buffer in buffer list
Desc:    move the indicated buffer to the end of the disk buffer chain (least-
      recently used is first); under DOS 3.3, the buffer is then moved to
      the start of the disk buffer chain if it was marked unused
Note:    this function is the same as AX=1207h except that it returns a
      pointer to the buffer following the specified buffer in the buffer
      chain
SeeAlso: AX=1207h
--------D-2F1210-----------------------------
INT 2F U - DOS 3+ internal - FIND UNREFERENCED DISK BUFFER
    AX = 1210h
    DS:DI -> first disk buffer to check
Return: ZF clear if found
        DS:DI -> first unreferenced disk buffer
    ZF set if not found
Note:    in DOS 5+, this has become essentially a NOP, invoking the same code
      used by AX=1224h (SHARING DELAY)
SeeAlso: AX=120Eh
--------D-2F1211-----------------------------
INT 2F U - DOS 3+ internal - NORMALIZE ASCIZ FILENAME
    AX = 1211h
    DS:SI -> ASCIZ filename to normalize
    ES:DI -> buffer for normalized filename
Return: destination buffer filled with uppercase filename, with slashes turned
    to backslashes
SeeAlso: AX=121Eh,AX=1221h
--------D-2F1212-----------------------------
INT 2F U - DOS 3+ internal - GET LENGTH OF ASCIZ STRING
    AX = 1212h
    ES:DI -> ASCIZ string
Return: CX = length of string
SeeAlso: AX=1225h
--------D-2F1213-----------------------------
INT 2F U - DOS 3+ internal - UPPERCASE CHARACTER
    AX = 1213h
    STACK: WORD character to convert to uppercase
Return: AL = uppercase character
    STACK unchanged
--------D-2F1214-----------------------------
INT 2F U - DOS 3+ internal - COMPARE FAR POINTERS
    AX = 1214h
    DS:SI = first pointer
    ES:DI = second pointer
Return: ZF set if pointers are equal, ZF clear if not equal
--------D-2F1215-----------------------------
INT 2F U - DOS 3+ internal - FLUSH BUFFER
    AX = 1215h
    DS:DI -> disk buffer
    SS = DOS DS (must be using a DOS internal stack)
    STACK: WORD drives for which to skip buffer
        ignore buffer if drive same as high byte, or bytes differ and
        the buffer is for a drive OTHER than that given in low byte
Return: STACK unchanged
Note:    can be called only from within DOS
SeeAlso: AX=1209h
--------D-2F1216-----------------------------
INT 2F U - DOS 3+ internal - GET ADDRESS OF SYSTEM FILE TABLE ENTRY
    AX = 1216h
    BX = system file table entry number
Return: CF clear if successful
        ES:DI -> system file table entry
    CF set if BX greater than FILES=
Note:    supported by DR-DOS 5+
SeeAlso: AX=1220h
--------D-2F1217-----------------------------
INT 2F U - DOS 3+ internal - GET CURRENT DIRECTORY STRUCTURE FOR DRIVE
    AX = 1217h
    SS = DOS DS (must be using a DOS internal stack)
    STACK: WORD drive (0 = A:, 1 = B:, etc)
Return: CF set on error
        (drive > LASTDRIVE)
    CF clear if successful
        DS:SI -> current directory structure for specified drive
    STACK unchanged
SeeAlso: AX=1219h
--------D-2F1218-----------------------------
INT 2F U - DOS 3+ internal - GET CALLER'S REGISTERS
    AX = 1218h
Return: DS:SI -> saved caller's AX,BX,CX,DX,SI,DI,BP,DS,ES (on stack)
Note:    only valid while within DOS
--------D-2F1219-----------------------------
INT 2F U - DOS 3+ internal - SET DRIVE???
    AX = 1219h
    SS = DOS DS (must be using a DOS internal stack)
    STACK: WORD drive (0 = default, 1 = A:, etc)
Return: ???
    STACK unchanged
Notes:    calls AX=1217h
    builds a current directory structure if inside server call
      (INT 21/AX=5D00h)
SeeAlso: AX=1217h,AX=121Fh
--------D-2F121A-----------------------------
INT 2F U - DOS 3+ internal - GET FILE'S DRIVE
    AX = 121Ah
    DS:SI -> filename
Return: AL = drive (0 = default, 1 = A:, etc, FFh = invalid)
    DS:SI -> filename without leading X: (if present)
SeeAlso: INT 21/AH=19h,INT 21/AH=60h
--------D-2F121B-----------------------------
INT 2F U - DOS 3+ internal - SET YEAR/LENGTH OF FEBRUARY
    AX = 121Bh
    CL = year - 1980
Return: AL = number of days in February
Note:    requires DS to be set to the DOS data segment
SeeAlso: INT 21/AH=2Bh
--------D-2F121C-----------------------------
INT 2F U - DOS 3+ internal - CHECKSUM MEMORY
    AX = 121Ch
    DS:SI -> start of memory to checksum
    CX = number of bytes
    DX = initial checksum
    SS = DOS DS (must be using a DOS internal stack)
Return: AX, CX destroyed
    DX = checksum
    DS:SI -> first byte after checksummed range
Notes:    used by DOS to determine day count since 1/1/80 given a date
    supported by DR-DOS 5.0+
SeeAlso: AX=121Dh
--------D-2F121D-----------------------------
INT 2F U - DOS 3+ internal - SUM MEMORY
    AX = 121Dh
    DS:SI -> memory to add up
    CX = 0000h
    DX = limit
Return: AL = byte which exceeded limit
    CX = number of bytes before limit exceeded
    DX = remainder after adding first CX bytes
    DS:SI -> byte beyond the one which exceeded the limit
Notes:    used by DOS to determine year or month given day count since 1/1/80
    supported by DR-DOS 5.0+
SeeAlso: AX=121Ch
--------D-2F121E-----------------------------
INT 2F U - DOS 3+ internal - COMPARE FILENAMES
    AX = 121Eh
    DS:SI -> first ASCIZ filename
    ES:DI -> second ASCIZ filename
Return: ZF set if filenames equivalent, ZF clear if not
Note:    supported by DR-DOS 5.0+
SeeAlso: AX=1211h,AX=1221h
--------D-2F121F-----------------------------
INT 2F U - DOS 3+ internal - BUILD CURRENT DIRECTORY STRUCTURE
    AX = 121Fh
    SS = DOS DS (must be using a DOS internal stack)
    STACK: WORD drive letter
Return: ES:DI -> current directory structure (will be overwritten by next call)
    STACK unchanged
--------D-2F1220-----------------------------
INT 2F U - DOS 3+ internal - GET JOB FILE TABLE ENTRY
    AX = 1220h
    BX = file handle
Return: CF set on error
        AL = 6 (invalid file handle)
    CF clear if successful
        ES:DI -> JFT entry for file handle in current process
Notes:    the byte pointed at by ES:DI contains the number of the SFT for the
      file handle, or FFh if the handle is not open
    supported by DR-DOS 5.0+
SeeAlso: AX=1216h,AX=1229h
--------D-2F1221-----------------------------
INT 2F U - DOS 3+ internal - CANONICALIZE FILE NAME
    AX = 1221h
    DS:SI -> file name to be fully qualified
    ES:DI -> 128-byte buffer for resulting canonical file name
    SS = DOS DS (must be using a DOS internal stack)
Return: (see INT 21/AH=60h)
Note:    identical to INT 21/AH=60h
SeeAlso: AX=1123h,INT 21/AH=60h
--------D-2F1222-----------------------------
INT 2F U - DOS 3+ internal - SET EXTENDED ERROR INFO
    AX = 1222h
    SS = DOS data segment
    SS:SI -> 4-byte records
        BYTE    error code, FFh = last record
        BYTE    error class, FFh = don't change
        BYTE    suggested action, FFh = don't change
        BYTE    error locus, FFh = don't change
    SDA error code set
Return: SI destroyed
    SDA error class, error locus, and suggested action fields set
Note:    can be called only from within DOS
SeeAlso: AX=122Dh,INT 21/AH=59h,INT 21/AX=5D0Ah
--------D-2F1223-----------------------------
INT 2F U - DOS 3+ internal - CHECK IF CHARACTER DEVICE
    AX = 1223h
    DS = DOS DS
    SS = DOS DS (must be using a DOS internal stack)
    SDA+218h (DOS 3.10-3.30) = eight-character blank-padded name
    SDA+22Bh (DOS 4.0-6.0) = eight-character blank-padded name
Return: CF set if no character device by that name found
    CF clear if found
        BH = low byte of device attribute word
Note:    can only be called from within DOS
SeeAlso: INT 21/AX=5D06h,INT 21/AX=5D0Bh
--------D-2F1224-----------------------------
INT 2F U - DOS 3+ internal - SHARING RETRY DELAY
    AX = 1224h
    SS = DOS DS (must be using a DOS internal stack)
Return: after delay set by INT 21/AX=440Bh, unless in server call
      (INT 21/AX=5D00h)
Note:    delay is dependent on the processor speed, and is skipped entirely if
      inside a server call
SeeAlso: INT 21/AX=440Bh,INT 21/AH=52h,INT 62/AX=0097h
--------D-2F1225-----------------------------
INT 2F U - DOS 3+ internal - GET LENGTH OF ASCIZ STRING
    AX = 1225h
    DS:SI -> ASCIZ string
Return: CX = length of string
Note:    supported by DR-DOS 5.0+
SeeAlso: AX=1212h
--------D-2F1226-----------------------------
INT 2F U - DOS 3.3+ internal - OPEN FILE
    AX = 1226h
    CL = access mode
    DS:DX -> ASCIZ filename
    SS = DOS DS (must be using a DOS internal stack)
Return: CF set on error
        AL = error code (see INT 21/AH=59h)
    CF clear if successful
        AX = file handle
Notes:    can only be called from within DOS
    equivalent to INT 21/AH=3Dh
    used by NLSFUNC to access COUNTRY.SYS when invoked by the DOS kernel
SeeAlso: AX=1227h,INT 21/AH=3Dh
--------D-2F1227-----------------------------
INT 2F U - DOS 3.3+ internal - CLOSE FILE
    AX = 1227h
    BX = file handle
    SS = DOS DS (must be using a DOS internal stack)
Return: CF set on error
        AL = 06h invalid file handle
    CF clear if successful
Notes:    can only be called from within DOS
    equivalent to INT 21/AH=3Eh
    used by NLSFUNC to access COUNTRY.SYS when invoked by the DOS kernel
SeeAlso: AX=1106h,AX=1201h,AX=1226h,INT 21/AH=3Eh
--------D-2F1228BP4200-----------------------
INT 2F U - DOS 3.3+ internal - MOVE FILE POINTER
    AX = 1228h
    BP = 4200h, 4201h, 4202h (see INT 21/AH=42h)
    BX = file handle
    CX:DX = offset in bytes
    SS = DOS DS (must be using a DOS internal stack)
Return: as for INT 21/AH=42h
Notes:    equivalent to INT 21/AH=42h, but may only be called from inside a DOS
      function call
    sets user stack frame pointer to dummy buffer, moves BP to AX, performs
      LSEEK, and restores frame pointer
    used by NLSFUNC to access COUNTRY.SYS when invoked by the DOS kernel
SeeAlso: INT 21/AH=42h
--------D-2F1229-----------------------------
INT 2F U - DOS 3.3+ internal - READ FROM FILE
    AX = 1229h
    BX = file handle
    CX = number of bytes to read
    DS:DX -> buffer
    SS = DOS DS (must be using a DOS internal stack)
Return: as for INT 21/AH=3Fh
Notes:    equivalent to INT 21/AH=3Fh, but may only be called when already inside
      a DOS function call
    used by NLSFUNC to access COUNTRY.SYS when invoked by the DOS kernel
SeeAlso: AX=1226h,INT 21/AH=3Fh
--------D-2F122A-----------------------------
INT 2F U - DOS 3.3+ internal - SET FASTOPEN ENTRY POINT
    AX = 122Ah
    BX = entry point to set (0001h or 0002h)
    DS:SI -> FASTOPEN entry point
        (entry point not set if SI = FFFFh for DOS 4+)
Return: CF set if specified entry point already set
Notes:    entry point in BX is ignored under DOS 3.30
    both entry points set to same handler by DOS 4.01
    DOS 5.0 and 6.0 only set entry point 1

DOS 3.30+ FASTOPEN is called with:
    AL = 01h  Lookup
        CX = ??? seems to be offset
        DI = ??? seems to be offset
        SI = offset in DOS DS of filename
    AL = 02h  insert file into FASTOPEN cache
    AL = 03h  delete file from FASTOPEN cache
        SI = offset in DOS DS of filename
    AL = 04h  purge FASTOPEN cache
        AH = subfunction (00h,01h,02h)
        ES:DI -> ???
        CX = ??? (subfunctions 01h and 02h only)
Returns: CF set on error or not installed
Note: function 03h calls function 01h first

PC-DOS 4.01 FASTOPEN is additionally called with:
    AL = 04h ???
        AH = 03h
        ???
    AL = 05h ???
    AL = 0Bh ???
    AL = 0Ch ???
    AL = 0Dh ???
    AL = 0Eh ???
    AL = 0Fh ???
    AL = 10h ???

MS-DOS 5.0-6.0 FASTOPEN is additionally called with:
    AL = 04h  purge FASTOPEN cache
        AH = 03h
        ???
    AL = 05h ???
        DL = drive (00h = A:)
        ???
    AL = 06h ???
        ???
--------D-2F122B-----------------------------
INT 2F U - DOS 3.3+ internal - IOCTL
    AX = 122Bh
    BP = 44xxh
    SS = DOS DS (must be using a DOS internal stack)
    additional registers as appropriate for INT 21/AX=44xxh
Return: as for INT 21/AH=44h
Notes:    equivalent to INT 21/AH=44h, but may only be called when already inside
      a DOS function call
    sets user stack frame pointer to dummy buffer, moves BP to AX, performs
      IOCTL, and restores frame pointer
    used by NLSFUNC in accessing COUNTRY.SYS when invoked by the DOS kernel
SeeAlso: INT 21/AH=44h
--------D-2F122C-----------------------------
INT 2F U - DOS 3.3+ internal - GET DEVICE CHAIN
    AX = 122Ch
Return: BX:AX -> header of second device driver (NUL is first) in driver chain
Note:    although this function exists in DR-DOS 5.0, it returns 0000h:0000h
SeeAlso: INT 21/AH=52h
--------D-2F122D-----------------------------
INT 2F U - DOS 3.3+ internal - GET EXTENDED ERROR CODE
    AX = 122Dh
Return: AX = current extended error code
SeeAlso: AX=1222h,INT 21/AH=59h
--------D-2F122E-----------------------------
INT 2F U - DOS 4+ internal - GET OR SET ERROR TABLE ADDRESSES
    AX = 122Eh
    DL = subfunction
        00h get standard DOS error table
        Return: ES:DI -> error table
                 (DOS 4: errors 00h-12h,50h-5Bh)
                 (DOS 5: errors 00h-26h,4Fh,51h-59h)
        01h set standard DOS error table
        ES:DI -> error table
        02h get parameter error table (errors 00h-0Ah)
        Return: ES:DI -> error table
        03h set parameter error table
        ES:DI -> error table
        04h get critical/SHARE error table (errors 13h-2Bh)
        Return: ES:DI -> error table
        05h set critical/SHARE error table
        ES:DI -> error table
        06h get ??? error table
        Return: ES:DI -> error table or 0000h:0000h
        07h set ??? error table
        ES:DI -> error table
        08h get error message retriever (see below)
        Return: ES:DI -> FAR procedure to fetch error message
        09h set ??? error table
        ES:DI -> error table
Notes:    if the returned segment on a "get" is 0001h, then the offset specifies
      the offset of the error message table within COMMAND.COM, and the
      procedure returned by DL=08h should be called
    DOS 5+ COMMAND.COM does not allow setting any of the addresses (calls
      with DL odd are ignored); they are always returned with segment 0001h
    for DOS 5.0, the standard and critical/SHARE error tables are combined
      into a single error table
SeeAlso: AX=0500h,INT 21/AH=59h

Format of DOS 4.x error table:
Offset    Size    Description
 00h    BYTE    FFh
 01h  2 BYTEs    04h,00h (DOS version???)
 03h    BYTE    number of error headers following
 04h 2N WORDs    table of all error headers for table
        Offset    Size    Description
         00h    WORD    error message number
         02h    WORD    offset of error message from start of header
                error messages are count byte followed by msg
Note:    DOS 5 error tables consist of one word per error number; each word
      contains either the offset of a counted string or 0000h

Call error retrieval function with:
    AX = error number
    DI = offset of error table
Return: ES:DI -> error message (counted string)
Notes:    this function needs to access COMMAND.COM if the messages were not
      loaded into memory permanently with /MSG; the caller should assume
      that the returned message will be overwritten by the next call of
      the function
    supported by DR-DOS 5.0

Values for parameter errors:
 01h    Too many parameters
 02h    Required Parameter missing
 03h    Invalid switch
 04h    Invalid keyword
 06h    Parameter value not in allowed range
 07h    Parameter value not allowed
 08h    Parameter value not allowed
 09h    Parameter format not correct
 0Ah    Invalid parameter
 0Bh    Invalid parameter combination
--------D-2F122F-----------------------------
INT 2F U - DOS 4.x internal - SET DOS VERSION NUMBER TO RETURN
    AX = 122Fh
    DX = DOS version number (0000h = return true DOS version)
Note:    not available under DR-DOS 5.0 or 6.0
SeeAlso: INT 21/AH=30h,INT 21/AX=3306h
--------O-2F12FFBX0006-----------------------
INT 2F U - DR-DOS 6 - VIDEO MEMORY SPACE CONTROL
    AX = 12FFh
    BX = 0006h
    DX = 0000h
    CX = function
        0000h get status of video memory space (MEMMAX /V)
        0001h map memory into video memory space (MEMMAX +V)
        0002h unmap memory from video memory space (MEMMAX -V)
Return: CF clear if successful
        AX = 0000h (successful)
        BX = segment of reserved video RAM
        CX = segment of used video RAM
        DX = segment of first upper MCB
Note:    this functionality is provided by EMM386, and partially supported by
      HIDOS.SYS
SeeAlso: AX=D201h/BX=4849h
--------D-2F13-------------------------------
INT 2F U - DOS 3.2+ - SET DISK INTERRUPT HANDLER
    AH = 13h
    DS:DX -> interrupt handler disk driver calls on read/write
    ES:BX = address to restore INT 13 to on system halt (exit from root
         shell) or warm boot (INT 19)
Return: DS:DX set by previous invocation of this function
    ES:BX set by previous invocation of this function
Notes:    IO.SYS hooks INT 13 and inserts one or more filters ahead of the
      original INT 13 handler.  The first is for disk change detection
      on floppy drives, the second is for tracking formatting calls and
      correcting DMA boundary errors, the third is for working around
      problems in a particular version of IBM's ROM BIOS
    before the first call, ES:BX points at the original BIOS INT 13; DS:DX
      also points there unless IO.SYS has installed a special filter for
      hard disk reads (on systems with model byte FCh and BIOS date
      "01/10/84" only), in which case it points at the special filter
    most DOS 3.2+ disk access is via the vector in DS:DX, although a few
      functions are still invoked via an INT 13 instruction
    this is a dangerous security loophole for any virus-monitoring software
      which does not trap this call ("INT13", "Nomenklatura", and many
      Bulgarian viruses are known to use it to get the original ROM entry
      point)
SeeAlso: INT 13/AH=01h,INT 19,INT 9D"VIRUS"
--------N-2F13-------------------------------
INT 2F U - MS-NET - ???
    AH = 13h
    ???
Return: ???
Note:    supposedly used to move (or control the movement of) NCBs
--------U-2F1400-----------------------------
INT 2F C - NLSFUNC.COM - INSTALLATION CHECK
    AX = 1400h
Return: AL = 00h not installed, OK to install
         01h not installed, not OK
         FFh installed
Notes:    this function is called by the DOS v3.3+ kernel
    supported by OS/2 v1.3+ compatibility box, which always returns AL=FFh
    supported by DR-DOS 5.0
    documented for MS-DOS 5+, but undocumented in prior versions
SeeAlso: AX=1401h"NLSFUNC",AX=1402h"NLSFUNC"
--------D-2F1400-----------------------------
INT 2F - European MS-DOS 4.0 POPUP - "CheckPu" - INSTALLATION CHECK
    AX = 1400h
Return: AX = FFFFh if installed
        BX = maximum memory required to save screen and keyboard info
    CF clear if successful
    CF set on error
        AX = error code
        0002h invalid function
        0004h unknown error
Note:    the POPUP interface is used by background programs (see INT 21/AH=80h)
      to communicate with the user
SeeAlso: AX=1401h"POPUP",AX=1402h"POPUP",AX=1403h"POPUP"
--------U-2F1401-----------------------------
INT 2F CU - NLSFUNC.COM - CHANGE CODE PAGE
    AX = 1401h
    DS:SI -> internal code page structure (see below)
    BX = new code page (see INT 21/AX=6602h)
    DX = country code???
Return: AL = status
         00h successful
         else DOS error code
Note:    this function is called by the DOS v3.3+ kernel
SeeAlso: AX=1400h"NLSFUNC",AX=1402h"NLSFUNC",INT 21/AH=66h

Format of DOS 3.30 internal code page structure:
Offset    Size    Description
 00h  8 BYTEs    ???
 08h 64 BYTEs    name of country information file
 48h    WORD    system code page
 4Ah    WORD    number of supported subfunctions
 4Ch  5 BYTEs    data to return for INT 21/AX=6502h
 51h  5 BYTEs    data to return for INT 21/AX=6504h
 56h  5 BYTEs    data to return for INT 21/AX=6505h
 5Bh  5 BYTEs    data to return for INT 21/AX=6506h
 60h 41 BYTEs    data to return for INT 21/AX=6501h
--------D-2F1401-----------------------------
INT 2F - European MS-DOS 4.0 POPUP - "PostPu" - OPEN/CLOSE POPUP SCREEN
    AX = 1401h
    DL = function (00h open, 01h close)
    DH = wait flag
        00h block until screen opens
        01h return error if screen is not available
        02h urgent--always open screen immediately
Return: CF clear if successful
        BX = amount of memory needed to save screen and keyboard info,
        0000h if default save location can be used (only if DH was 02h)
    CF set on error
Note:    the application using the screen is frozen until the popup screen is
      closed
SeeAlso: AX=1400h"POPUP",AX=1402h"POPUP",AX=1403h"POPUP"
--------U-2F1402-----------------------------
INT 2F CU - NLSFUNC.COM - GET EXTENDED COUNTRY INFO
    AX = 1402h
    BP = subfunction (same as AL for INT 21/AH=65h)
    BX = code page (see INT 21/AX=6602h)
    DX = country code (see INT 21/AH=38h)
    DS:SI -> internal code page structure (see AX=1401h)
    ES:DI -> user buffer
    CX = size of user buffer
Return: AL = status
        00h successful
        else DOS error code
Notes:    this function is called by the DOS v3.3+ kernel on INT 21/AH=65h
    code page structure apparently only needed for COUNTRY.SYS pathname
SeeAlso: AX=1401h"NLSFUNC",AX=1403h"NLSFUNC",AX=1404h,INT 21/AH=65h
--------D-2F1402-----------------------------
INT 2F - European MS-DOS 4.0 POPUP - "SavePu" - SAVE POPUP SCREEN
    AX = 1402h
    ES:DI -> save buffer (0000h:0000h for default buffer in POPUP)
Return: CF clear if successful
    CF set on error
        AX = error code
        0001h process does not own screen
        0004h unknown error
        0005h invalid pointer
SeeAlso: AX=1400h"POPUP",AX=1401h"POPUP",AX=1403h"POPUP"
--------U-2F1403-----------------------------
INT 2F CU - NLSFUNC.COM - SET CODE PAGE
    AX = 1403h
    DS:SI -> internal code page structure (see AX=1401h)
    BX = code page (see INT 21/AX=6602h)
    DX = country code (see INT 21/AH=38h)
Return: AL = status
         ???
Note:    this function is called by the DOS v3.3+ kernel on INT 21/AH=38h
SeeAlso: AX=1402h"NLSFUNC",AX=1404h,INT 21/AH=38h"SET"
--------D-2F1403-----------------------------
INT 2F - European MS-DOS 4.0 POPUP - "RestorePu" - RESTORE SCREEN
    AX = 1403h
    ES:DI -> buffer containing saved screen
        (0000h:0000h for default buffer in POPUP)
Return: CF clear if successful
    CF set on error
        AX = error code (see AX=1402h"POPUP")
SeeAlso: AX=1400h"POPUP",AX=1401h"POPUP",AX=1402h"POPUP"
--------U-2F1404-----------------------------
INT 2F CU - NLSFUNC.COM - GET COUNTRY INFO
    AX = 1404h
    BX = code page (see INT 21/AX=6602h)
    DX = country code (see INT 21/AH=38h)
    DS:SI -> internal code page structure (see AX=1401h)
    ES:DI -> user buffer
Return: AL = status
         ???
Notes:    this function is called by the DOS v3.3+ kernel on INT 21/AH=38h
    code page structure apparently only needed for COUNTRY.SYS pathname
SeeAlso: AX=1402h,AX=1403h,INT 21/AH=38h"GET"
--------U-2F14FE-----------------------------
INT 2F U - DR-DOS 5.0 NLSFUNC - GET EXTENDED COUNTRY INFORMATION
    AX = 14FEh
    BX = code page (FFFFh=global code page) (see INT 21/AX=6602h)
    DX = country ID (FFFFh=current country) (see INT 21/AH=38h)
    ES:DI -> country information buffer
    CL = 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 get pointer to Double-Byte Character Set table
    CF set (used to return error if not installed)
Return: CF clear if successful
        DS:SI -> requested information
    CF set on error
Notes:    DR-DOS 5.0 NLSFUNC returns CF set and AX=0001h if AL was not 00h, FEh,
      or FFh on entry.
    the DR-DOS kernel calls this function on INT 21/AX=6501h
    the value in CL is not range-checked by the DR-DOS 5.0 NLSFUNC
SeeAlso: AX=14FFh,INT 21/AH=65h

Format of DR-DOS COUNTRY.SYS file:
Offset    Size    Description
 00h 126 BYTEs    copyright notice (terminated with Ctrl-Z, padded with NULs)
 7Eh    WORD    signature EDC1h
 80h    var    country pointer records
    Offset    Size    Description
     00h    WORD    country code (0000h if end of array)
     02h    WORD    code page
     04h    WORD    ??? (0000h)
     06h  7 WORDs    offsets in file for data tables for subfunctions
            01h-07h
 var    var    country information
--------U-2F14FF-----------------------------
INT 2F U - DR-DOS 5.0 NLSFUNC - PREPARE CODE PAGE
    AX = 14FFh
    BX = code page
Return: AX = ???
    ZF set if AX=0000h
Notes:    DR-DOS 5.0 NLSFUNC returns CF set and AX=0001h if AL was not 00h, FEh,
      or FFh on entry.
    passes codepage preparation request to each character device supporting
      the generic IOCTL call
SeeAlso: AX=14FEh,INT 21/AX=440Ch,INT 21/AX=6602h
--------U-2F1500-----------------------------
INT 2F - DOS 4.00 GRAPHICS.COM - INSTALLATION CHECK
    AX = 1500h
Return: AX = FFFFh
    ES:DI -> ??? (graphics data?)
Note:    this installation check conflicts with the CD-ROM Extensions
      installation check; moved to AX=AC00h in later versions
SeeAlso: AX=AC00h
--------d-2F1500BX0000-----------------------
INT 2F - CD-ROM - INSTALLATION CHECK
    AX = 1500h
    BX = 0000h
Return: BX = number of CD-ROM drive letters used
    CX = starting drive letter (0=A:)
Notes:    this installation check DOES NOT follow the format used by other
      software
    this installation check conflicts with the DOS 4.00 GRAPHICS.COM
      installation check
SeeAlso: INT 2F/AX=D000h"Lotus"
--------d-2F1501-----------------------------
INT 2F - CD-ROM - GET DRIVE DEVICE LIST
    AX = 1501h
    ES:BX -> buffer to hold drive letter list (5 bytes per drive letter)
Return: buffer filled, for each drive letter
      BYTE    subunit number in driver
      DWORD address of device driver header
--------d-2F1502-----------------------------
INT 2F - CD-ROM - GET COPYRIGHT FILE NAME
    AX = 1502h
    ES:BX -> 38-byte buffer for name of copyright file
    CX = drive number (0=A:)
Return: CF set if drive is not a CD-ROM drive
        AX = 000Fh (invalid drive)
    CF clear if successful
SeeAlso: AX=1503h
--------d-2F1503-----------------------------
INT 2F - CD-ROM - GET ABSTRACT FILE NAME
    AX = 1503h
    ES:BX -> 38-byte buffer for name of abstract file
    CX = drive number (0=A:)
Return: CF set if drive is not a CD-ROM drive
        AX = 000Fh (invalid drive)
    CF clear if successful
SeeAlso: AX=1502h,AX=1504h
--------d-2F1504-----------------------------
INT 2F - CD-ROM - GET BIBLIOGRAPHIC DOC FILE NAME
    AX = 1504h
    ES:BX -> 38-byte buffer for name of bibliographic documentation file
    CX = drive number (0=A:)
Return: CF set if drive is not a CD-ROM drive
        AX = 000Fh (invalid drive)
    CF clear if successful
SeeAlso: AX=1502h,AX=1503h
--------d-2F1505-----------------------------
INT 2F - CD-ROM - READ VTOC
    AX = 1505h
    ES:BX -> 2048-byte buffer
    CX = drive number (0=A:)
    DX = sector index (0=first volume descriptor,1=second,...)
Return: CF set on error
        AX = error code (15=invalid drive,21=not ready)
    CF clear if successful
        AX = volume descriptor type (1=standard,FFh=terminator,0=other)
--------d-2F1506-----------------------------
INT 2F - CD-ROM - TURN DEBUGGING ON
    AX = 1506h
    BX = debugging function to enable
Note:    reserved for development
SeeAlso: AX=1507h
--------d-2F1507-----------------------------
INT 2F - CD-ROM - TURN DEBUGGING OFF
    AX = 1507h
    BX = debugging function to disable
Note:    reserved for development
SeeAlso: AX=1506h
--------d-2F1508-----------------------------
INT 2F - CD-ROM - ABSOLUTE DISK READ
    AX = 1508h
    ES:BX -> buffer
    CX = drive number (0=A:)
    SI:DI = starting sector number
    DX = number of sectors to read
Return: CF set on error
        AL = error code (15=invalid drive,21=not ready)
    CF clear if successful
SeeAlso: AX=1509h
--------d-2F1509-----------------------------
INT 2F - CD-ROM - ABSOLUTE DISK WRITE
    AX = 1509h
    ES:BX -> buffer
    CX = drive number (0=A:)
    SI:DI = starting sector number
    DX = number of sectors to write
Note:    corresponds to INT 26h and is currently reserved and nonfunctional
SeeAlso: AX=1508h
--------d-2F150A-----------------------------
INT 2F - CD-ROM - RESERVED
    AX = 150Ah
--------d-2F150B-----------------------------
INT 2F - CD-ROM v2.00+ - DRIVE CHECK
    AX = 150Bh
    CX = drive number (0=A:)
Return: BX = ADADh if MSCDEX.EXE installed
        AX = 0000h if drive not supported
        nonzero if supported
SeeAlso: AX=150Dh
--------d-2F150C-----------------------------
INT 2F - CD-ROM v2.00+ - GET MSCDEX.EXE VERSION
    AX = 150Ch
Return: BH = major version
    BL = minor version
Note:    MSCDEX.EXE versions prior to 2.00 return BX=0
--------d-2F150D-----------------------------
INT 2F - CD-ROM v2.00+ - GET CD-ROM DRIVE LETTERS
    AX = 150Dh
    ES:BX -> buffer for drive letter list (1 byte per drive)
Return: buffer filled with drive numbers (0=A:).  Each byte corresponds
    to the drive in the same position for function 1501h
SeeAlso: AX=150Bh
--------d-2F150E-----------------------------
INT 2F - CD-ROM v2.00+ - GET/SET VOLUME DESCRIPTOR PREFERENCE
    AX = 150Eh
    BX = subfunction
        00h get preference
        DX = 0000h
        Return: DX = preference settings
        01h set preference
        DH = volume descriptor preference
            01h = primary volume descriptor
            02h = supplementary volume descriptor
        DL = supplementary volume descriptor preference
            01h = shift-Kanji
    CX = drive number (0=A:)
Return: CF set on error
        AX = error code (15=invalid drive,1=invalid function)
    CF clear if successful
--------d-2F150F-----------------------------
INT 2F - CD-ROM v2.00+ - GET DIRECTORY ENTRY
    AX = 150Fh
    CL = drive number (0=A:)
    CH bit 0 = copy flag
        clear if direct copy
        set if copy to structure which removes ISO/High Sierra diffs
    ES:BX -> ASCIZ path name
    SI:DI -> buffer for directory entry (see below)
         minimum 255 bytes for direct copy
Return: CF set on error
        AX = error code
    CF clear if successful
        AX = disk format (0=High Sierra,1=ISO 9660)

Format of directory entry (direct copy):
Offset    Size    Description
 00h    BYTE  length of directory entry
 01h    BYTE  length of XAR in Logical Block Numbers
 02h    DWORD LBN of data, Intel (little-endian) format
 06h    DWORD LBN of data, Motorola (big-endian) format
 0Ah    DWORD length of file, Intel format
 0Eh    DWORD length of file, Motorola format
---High Sierra---
 12h  6 BYTEs date and time
 18h    BYTE  bit flags
 19h    BYTE  reserved
---ISO 9660---
 12h  7 BYTEs date and time
 19h    BYTE  bit flags
---both formats---
 1Ah    BYTE  interleave size
 1Bh    BYTE  interleave skip factor
 1Ch    WORD  volume set sequence number, Intel format
 1Eh    WORD  volume set sequence number, Motorola format
 20h    BYTE  length of file name
 21h  N BYTEs file name
    BYTE (optional) padding if filename is odd length
      N BYTEs system data

Format of directory entry (canonicalized):
Offset    Size    Description
 00h    BYTE    length of XAR in Logical Block Numbers
 01h    DWORD    Logical Block Number of file start
 05h    WORD    size of disk in logical blocks
 07h    DWORD    file length in bytes
 0Bh  7 BYTEs    date and time
 12h    BYTE    bit flags
 13h    BYTE    interleave size
 14h    BYTE    interleave skip factor
 15h    WORD    volume set sequence number
 17h    BYTE    length of file name
 18h 38 BYTEs    ASCIZ filename
 3Eh    WORD    file version number
 40h    BYTE    number of bytes of system use data
 41h 220 BYTEs    system use data
--------d-2F1510-----------------------------
INT 2F - CD-ROM v2.10+ - SEND DEVICE DRIVER REQUEST
    AX = 1510h
    CX = CD-ROM drive letter (0 = A, 1 = B, etc)
    ES:BX -> CD-ROM device driver request header (see AX=0802h)
--------W-2F1600-----------------------------
INT 2F - MS Windows - WINDOWS ENHANCED MODE INSTALLATION CHECK
    AX = 1600h
Return: AL = status
        00h neither Windows 3.x enhanced mode nor Windows/386 2.x running
        01h Windows/386 2.x running
        80h XMS version 1 driver installed (neither Windows 3.x enhanced
         mode nor Windows/386 2.x running) (obsolete--see note)
        FFh Windows/386 2.x running
    AL = anything else
        AL = Windows major version number >= 3
        AH = Windows minor version number
Notes:    INT 2F/AH=16h comprises an API for non-Windows programs (DOS device
      drivers, TSRs, and applications) to cooperate with multitasking
      Windows/386 2.x and Windows 3.x and higher enhanced mode.
    certain calls are also supported in the Microsoft 80286 DOS extender in
      Windows standard mode
    this function served as the installation check and AX=1610h served to
      get the driver entry point for XMS version 1, which is now obsolete.
      Use AX=4300h and AX=4310h instead
SeeAlso: AX=160Ah,AX=1610h,AX=4300h,AX=4680h
Index:    installation check;XMS version 1
--------W-2F1602-----------------------------
INT 2F - MS Windows/386 2.x - GET API ENTRY POINT
    AX = 1602h
Return: ES:DI -> Windows/386 2.x API procedure entry point
Notes:    this interface is supported in Windows 3.x only for 2.x compatibility
    to get the current virtual machine (VM) ID in Windows/386 2.x:
        AX = 0000h
        ES:DI -> return address
        JUMP to address returned from INT 2F/AX=1602h
    After JUMP, at return address:
        BX = current VM ID.
SeeAlso: AX=C020h
--------W-2F1603-----------------------------
INT 2F - MS Windows/386 - GET INSTANCE DATA
    AX = 1603h
Return: AX = 5248h ('RH') if supported
        DS:SI -> Windows/386 instance data (see below)
Notes:    reportedly supported by RM Nimbus MS-DOS 3.3 kernel
    this function is called by DOSMGR when AX=1607h/BX=0015h is not
      supported, as is the case in DOS versions prior to 5.0
    see Geoff Chappell's book _DOS_Internals_ for additional discussions of
      this function, DOSMGR's behavior, and instancing in general
SeeAlso: AX=1607h/BX=0015h

Format of Windows/386 instance data:
Offset    Size    Description
 00h    WORD    segment of IO.SYS (0000h = default 0070h)
 02h    WORD    offset in IO.SYS of STACKS data structure (DOS 3.2x)
        0000h if not applicable
 04h    WORD    number of instance data entries (max 32)
 06h    Array of instance data entries
    Offset    Size    Description
     00h    WORD    segment (0002h = DOS kernel)
     02h    WORD    offset
     04h    WORD    size
--------W-2F1605-----------------------------
INT 2F - MS Windows - WINDOWS ENH MODE & 286 DOSX INIT BROADCAST
    AX = 1605h
    ES:BX = 0000h:0000h
    DS:SI = 0000h:0000h
    CX = 0000h
    DX = flags
        bit 0 = 0 if Windows enhanced-mode initialization
        bit 0 = 1 if Microsoft 286 DOS extender initialization
        bits 1-15 reserved (undefined)
    DI = version number (major in upper byte, minor in lower)
Return: CX = 0000h if okay for Windows to load
    CX = FFFFh (other registers unchanged) if Windows 3.0 in standard mode
    CX <> 0 if Windows should not load
    ES:BX -> startup info structure (see below)
    DS:SI -> virtual86 mode enable/disable callback or 0000h:0000h
Notes:    the Windows enhanced mode loader and Microsoft 286 DOS extender will
      broadcast an INT 2F/AX=1605h call when initializing.    Any DOS device
      driver or TSR can watch for this broadcast and return the appropriate
      values.  If the driver or TSR returns CX <> 0, it is also its
      responsibility to display an error message.
    each handler must first chain to the prior INT 2F handler with
      registers unchanged before processing the call
    if the handler requires local data on a per-VM basis, it must store the
      returned ES:BX in the "next" field of a startup info structure and
      return a pointer to that structure in ES:BX
    a single TSR may set the V86 mode enable/disable callback; if DS:SI is
      already nonzero, the TSR must fail the initialization by setting CX
      nonzero
    MSD checks for Windows 3.0 running in standard mode by testing whether
      CX=FFFFh and other registers are unchanged on return
SeeAlso: AX=1606h,AX=1608h,AX=4B05h

Format of Startup Information Structure:
Offset    Size    Description
 00h  2 BYTEs    major, minor version of info structure
 02h    DWORD    pointer to next startup info structure or 0000h:0000h
 06h    DWORD    pointer to ASCIZ name of virtual device file or 0000h:0000h
 0Ah    DWORD    virtual device reference data (see below)
        (only used if above nonzero)
 0Eh    DWORD    pointer to instance data records or 0000h:0000h

Format of one Instance Item in array:
Offset    Size    Description
 00h    DWORD    address of instance data (end of array if 0000h:0000h)
 04h    WORD    size of instance data

Format of Virtual Device Reference Data:
Offset    Size    Description
 00h    DWORD    physical address of ??? or 00000000h
 04h    DWORD    physical address of ??? table
 08h    DWORD    "DEST_PAGE" address to which pages must be mapped
 0Ch  N DWORDs    "SRC_PAGE" physical addresses of the pages
        00000000h = end of table
Note:    EMM386.EXE sets the first pointer to the start of the device driver
      chain, the second pointer to a field of 40h bytes followed by a
      16-bit offset to the end of the SRC_PAGE table, and DEST_PAGE to
      the start segment of the UMB area

Virtual mode enable/disable procedure called with:
    AX = 0000h disable V86 mode
    AX = 0001h enable V86 mode
    interrupts disabled
Return: CF set on error
    CF clear if successful
    interrupts disabled
--------W-2F1606-----------------------------
INT 2F - MS Windows - WINDOWS ENH MODE & 286 DOSX EXIT BROADCAST
    AX = 1606h
    DX = flags
        bit 0 = 0 if Windows enhanced-mode exit
        bit 0 = 1 if Microsoft 286 DOS extender exit
        bits 1-15 reserved (undefined)
Notes:    if the init broadcast fails (AX=1605h returned CX <> 0), then this
      broadcast will be issued immediately.
    this call will be issued in real mode
SeeAlso: AX=1605h,AX=1609h
--------W-2F1607-----------------------------
INT 2F - MS Windows - VIRTUAL DEVICE CALL OUT API
    AX = 1607h
    BX = virtual device ID (see INT 2F/AX=1684h)
    CX = (usually) callout subfunction
Return: (usually) AX,BX,CX,DX,ES contain results
Notes:    more of a convention than an API, this call specifies a standard
      mechanism for Windows enhanced-mode virtual devices (VxD's) to talk
      to DOS device drivers and TSRs
    see below for details on several virtual devices
SeeAlso: AX=1605h,AX=1607h/BX=000Ch,AX=1607h/BX=0014h,AX=1607h/BX=0015h
SeeAlso: AX=1684h,AX=C020h
--------W-2F1607BX0006-----------------------
INT 2F - MS Windows - "V86MMGR" VIRTUAL DEVICE API
    AX = 1607h
    BX = 0006h (VxD identifier of "V86MMGR")
    CX = 0000h
Return: AX = status
        0000h if local A20 state changed
        1607h if A20 unchanged
        other if global A20 state changed
--------W-2F1607BX000C-----------------------
INT 2F - MS Windows - "VMD" VIRTUAL MOUSE DEVICE API
    AX = 1607h
    BX = 000Ch (VxD identifier of "VMD")
Return: CX = nonzero if mouse driver already virtualized
Note:    VMD (Virtual Mouse Driver) calls this and then checks whether CX is
      nonzero; if yes, it will not automatically virtualize the mouse
      driver.  This would be used if MOUSE.COM already virtualizes
      itself using the Windows API.
SeeAlso: AX=1607h/BX=0014h,AX=1607h/BX=0015h
--------W-2F1607BX0014-----------------------
INT 2F - MS Windows - "VNETBIOS" VIRTUAL DEVICE API
    AX = 1607h
    BX = 0014H (VxD identifier of "VNETBIOS")
Return: ES:DI -> 128-byte table specifying VNETBIOS actions for each NetBIOS
        command code (see below)
Note:    VNETBIOS (Virtual NetBIOS) calls this function to determine whether
      the NetBIOS has an extensions Windows should know about
SeeAlso: AX=1607h/BX=000Ch,AX=1607h/BX=0015h

Values for action code:
 00h    "VN_Unknown" unknown command
 04h    "VN_No_Map"  no memory mapping necessary
 08h    "VN_Map_In"  input buffer is quickly used, so no global mapping needed
 0Ch    "VN_Map_In"  output buffer is quickly used, so no global mapping needed
 10h    "VN_Map_In_Out"     buffer is quickly used, so no global mapping needed
 14h    "VN_Chain_Send"     the chain-send command
 18h    "VN_Cancel"    special case for cancel command
 1Ch    "VN_Buffer_In"    buffer is incoming
 20h    "VN_Buffer_Out" buffer is outgoing
 24h    "VN_Buffer_In_Out" buffer used for both incoming and outgoing data
--------D-2F1607BX0015-----------------------
INT 2F - MS Windows - "DOSMGR" VIRTUAL DEVICE API
    AX = 1607h
    BX = 0015h (VxD identifier of "DOSMGR")
    CX = function
        0000h query instance processing
        DX = 0000h
        Return: CX = state
                0000h not instanced
                other instanced (DOS 5+ kernel returns 0001h)
                DX = segment of DOS drivers or 0000h for
                    default of 0070h
                ES:BX -> patch table (see below)
        0001h set patches in DOS
        DX = bit mask of patch requests
            bit 0 enable critical sections
            bit 1 NOP setting/checking user ID
            bit 2 turn INT 21/AH=3Fh on STDIN into polling loop
            bit 3 trap stack fault in "SYSINIT" to WIN386
            bit 4 BIOS patch to trap "Insert disk X:" to WIN386
        Return: AX = B97Ch
            BX = bit mask of patches applied
            DX = A2ABh
        0002h remove patches in DOS (ignored by DOS 5.0 kernel)
        DX = bit mask of patch requests (see function 0001h)
        0003h get size of DOS data structures
        DX = bit mask of request (only one bit can be set)
            bit 0: Current Directory Structure size
        Return: if supported request:
                AX = B97Ch
                CX = size in bytes of requested structure
                DX = A2ABh
            else:
                all registers preserved
        0004h determine instanced data structures
        Return: AX = B97Ch if supported
            DX = A2ABh if supported (DOS 5+ kernel returns 0000h)
            BX = bit mask of instanced items
                bit 0: CDS
                bit 1: SFT
                bit 2: device list
                bit 3: DOS swappable data area
        0005h get device driver size
        ES = segment of device driver
        Return: DX:AX = 0000h:0000h on error (not dev. driver segment)
            DX:AX = A2ABh:B97Ch if successful
                BX:CX = size of device driver in bytes
Notes:    DOSMGR (DOS Manager) will check whether the OEM DOS/BIOS data has
      been instanced via this API and will not perform its own default
      instancing of the normal DOS/BIOS data if so; if this API is not
      supported, DOSMGR will also try to access instancing data through
      INT 2F/AX=1603h
    these functions are supported by the DOS 5+ kernel; DOSMGR contains
      tables of instancing information for earlier versions of DOS
    see Geoff Chappell's book _DOS_Internals_ for additional discussions of
      DOSMGR's behavior and instancing in general
SeeAlso: AX=1603h,AX=1605h,AX=1607h/BX=000Ch,AX=1607h/BX=0014h,AX=1684h

Format of patch table:
Offset    Size    Description
 00h  2 BYTEs    DOS version (major, minor)
 02h    WORD    offset in DOS data segment of "SAVEDS"
 04h    WORD    offset in DOS data segment of "SAVEBX"
 06h    WORD    offset in DOS data segment of InDOS flag
 08h    WORD    offset in DOS data segment of User ID word
 0Ah    WORD    offset in DOS data segment of "CritPatch" table to enable
        critical section calls (see INT 2A/AH=80h)
 0Ch    WORD    (DOS 5+ only) offset in DOS data segment of "UMB_HEAD",
        containing segment of last MCB in conventional memory
--------E-2F1607BX22C0-----------------------
INT 2F - Rational Systems DOS/4GW - ???
    AX = 1607h
    BX = 22C0h
    ???
Return: ???
SeeAlso: INT 15/AX=BF02h,INT 15/AX=BF04h
--------W-2F1608-----------------------------
INT 2F C - MS Windows - WINDOWS ENHANCED MODE INIT COMPLETE BROADCAST
    AX = 1608h
Notes:    called after all installable devices have been initialized
    real-mode software may be called between the Windows enhanced-mode init
      call (AX=1605h) and this call; the software must detect this
      situation
SeeAlso: AX=1605h,AX=1609h
--------W-2F1609-----------------------------
INT 2F C - MS Windows - WINDOWS ENHANCED MODE BEGIN EXIT BROADCAST
    AX = 1609h
Note:    called at the beginning of a normal exit sequence; not made in the
      event of a fatal system crash
SeeAlso: AX=1606h,AX=1608h
--------W-2F160A-----------------------------
INT 2F - MS Windows 3.1 - IDENTIFY WINDOWS VERSION AND TYPE
    AX = 160Ah
Return: AX = 0000h if call supported
        BX = version (BH=major, BL=minor)
        CX = mode (0002h = standard, 0003h = enhanced)
SeeAlso: AX=1600h,AX=4680h
--------W-2F160B-----------------------------
INT 2F - MS Windows 3.1 - IDENTIFY TSRs
    AX = 160Bh
    ES:DI -> communication structure (see below) or 0000h:0000h
Return: ES:DI -> communication structure
Desc:    this call allows Windows-aware TSRs to make themselves known to
      Windows.
Note:    the TSR should allocate a communication structure, place the given
      ES:DI pointer in the first field, and return a pointer to the new
      structure
SeeAlso: AX=1605h,AX=160Ch,AX=4B01h,AX=4B05h

Format of TSR-to-Windows communication structure:
Offset    Size    Description
 00h    DWORD    pointer to next structure
 04h    WORD    PSP segment
 06h    WORD    API version ID (0100h)
 08h    WORD    EXEC flags
        bit 0: "WINEXEC"
        bit 1: "LOADLIBRARY"
        bit 2: "OPENDRIVER"
 0Ah    WORD    "exec_cmd_show"
 0Ch    DWORD    "exec_cmd"
 10h  4 BYTEs    reserved (0)
 14h    DWORD    pointer to TSR ID block (see below)
 18h    DWORD    pointer to TSR data block or 0000h:0000h

Format of Norton Utilities 6.0 TSR ID block:
Offset    Size    Description
 00h    WORD    length of name string
 02h  N BYTEs    name of TSR's executable
--------W-2F160C-----------------------------
INT 2F - MS Windows 3.1 - DETECT ROMs
    AX = 160Ch
    ???
Return: ???
Note:    used by ROM Windows
SeeAlso: AX=160Bh
--------m-2F1610-----------------------------
INT 2F - XMS v1.x only - GET DRIVER ADDRESS
    AX = 1610h
    details unavailable
Note:    this function and AX=1600h were only used in XMS version 1 and are now
      obsolete.  Use AX=4300h and AX=4310h instead
SeeAlso: AX=1600h,AX=4310h
--------W-2F1680-----------------------------
INT 2F - MS Windows, DPMI, various - RELEASE CURRENT VIRTUAL MACHINE TIME-SLICE
    AX = 1680h
Return: AL = 00h if the call is supported
    AL = 80h (unchanged) if the call is not supported
Notes:    programs can use this function in idle loops to enhance performance
      under multitaskers; this call is supported by MS Windows 3.0, DOS 5+,
      DPMI 1.0+, and will be supported in OS/2 2.0 for multitasking DOS
      applications
    does not block the program; it just gives up the remainder of the time
      slice
    should not be used by Windows-specific programs
SeeAlso: INT 15/AX=1000h,INT 15/AX=5305h,INT 21/AH=89h,INT 7A/BX=000Ah
--------W-2F1681-----------------------------
INT 2F - MS Windows 3+ - BEGIN CRITICAL SECTION
    AX = 1681h
Notes:    used to prevent a task switch from occurring
    should be followed by an INT 2F/AX=1682h call as soon as possible
    nested calls are allowed, and must be followed by an appropriate number
      of "end critical section" calls
    not supported in Windows/386 2.x. Get INDOS flag with INT 21/AH=34h and
      increment by hand.
SeeAlso: AX=1682h,INT 15/AX=101Bh,INT 21/AH=34h
--------W-2F1682-----------------------------
INT 2F - MS Windows 3+ - END CRITICAL SECTION
    AX = 1682h
Notes:    not supported in Windows/386 2.x.  Get InDOS flag with INT 21/AH=34h
      and decrement by hand, taking care not to decrement InDOS flag
      through zero
SeeAlso: AX=1681h,INT 15/AX=101Ch,INT 21/AH=34h
--------W-2F1683-----------------------------
INT 2F - MS Windows 3+ - GET CURRENT VIRTUAL MACHINE ID
    AX = 1683h
Return: BX = current virtual machine (VM) ID
Notes:    Windows itself currently runs in VM 1, but this can't be relied upon
    VM IDs are reused when VMs are destroyed
    an ID of 0 will never be returned
SeeAlso: AX=1684h,AX=1685h,AX=168Bh
--------W-2F1684-----------------------------
INT 2F - MS Windows - GET DEVICE API ENTRY POINT
    AX = 1684h
    BX = virtual device (VxD) ID (see below)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point, or 0:0 if the VxD does not support an API
Note:    some Windows enhanced-mode virtual devices provide services that
      applications can access.  For example, the Virtual Display Device
      (VDD) provides an API used in turn by WINOLDAP.
SeeAlso: AX=1683h

Values for VxD ID:
Value  Name    CallOut V86 PM    Description
 01h    VMM        N  N    Virtual Machine Manager
 02h    Debug
 03h    VPICD        Y  Y    Virtual Prog. Interrupt Controller (PIC) Device
 04h    VDMAD        N  N    Virtual Direct Memory Access (DMA) Device
 05h    VTD        Y  Y    Virtual Timer Device
 06h    V86MMGR        N  N    Virtual 8086 Mode Device
 07h    PageSwap    N  N    Paging Device
 08h    Parity        N  N    Parity-check trapper
 09h    Reboot        N  Y    Ctrl-Alt-Del handler
 0Ah    VDD        N  Y    Virtual Display Device (GRABBER)
 0Bh    VSD        N  N    Virtual Sound Device
 0Ch    VMD      Y    Y  Y    Virtual Mouse Device
 0Dh    VKD        N  Y    Virtual Keyboard Device
 0Eh    VCD        N  Y    Virtual COMM Device
 0Fh    VPD            Virtual Printer Device
 10h    VHD            Virtual Hard Disk Device (Windows 3.0)
 10h    BLOCKDEV    N  N    Virtual Hard Disk Device (Windows 3.1)
 10h    IOS        N  Y    (Chicago)
 11h    VMCPD        Y  Y    Virtual Math CoProcessor Device
 12h    EBIOS        N  N    Reserve EBIOS page (e.g., on PS/2)
 13h    BIOSXLAT    N  N    Map ROM BIOS API between prot & V86 mode
 14h    VNETBIOS  Y    N  N    Virtual NetBIOS Device
 15h    DOSMGR        Y  N
 16h    WINLOAD
 17h    SHELL        N  Y
 18h    VMPOLL        N  N
 19h    VPROD
 1Ah    DOSNET        N  N    assures network integrity across VMs
 1Ah    VNETWARE    Y  Y    Novell NetWare DOSNET replacement
 1Bh    VFD        N  N    Virtual Floppy Device
 1Ch    VDD2            Secondary display adapter
 1Ch    LoadHi        N  N    Netroom LoadHi Device (RMLODHI.VXD)
 1Ch    LoadHi        N  N    386MAX LoadHi Device (386MAX.VXD)
 1Ch    LoadHi        N  N    Win386 LoadHi Device (EMM386.EXE)
 1Dh    WINDEBUG    N  Y
 1Dh    TDDebug        N  Y
 1Eh    TSRLoad            TSR instance utility
 1Fh    BiosHook        BIOS interrupt hooker VxD
 20h    Int13       N    N  N
 21h    PageFile    N  Y    Paging File device
 22h    SCSI
 23h    MCA_POS
 24h    SCSIFD            SCSI FastDisk device
 25h    VPEND            Pen device
 26h    APM            Advanced Power Management
 27h    VXDLDR        Y  Y    (Chicago)
 2Ah    VWIN32        N  Y    (Chicago)
 2Bh    VCOMM        Y  Y    (Chicago)
 30h    MACH32        N  Y    ATI Mach32 video card
 33h    CONFIGMG    Y  Y    (Chicago)
 33h    EDOS        N  N    Windows DOS Box Enhancer by Mom's Software
 36h    VFBACKUP    Y  Y    (Chicago)
 38h    VCOND        Y  Y    (Chicago)
 51h    ISAPNP        N  N
 8Dh    ESDI_506    N  N    (Chicago)
 90h    voltrack    N  N
 FDh    FAKEIDE        N  N    (Chicago)
0102h    CV1        N  N    Microsoft C/C++ 7.00+ CodeView for Windows
0200h    VIPX        Y  Y    NetWare Virtual IPX Driver
0201h    VNWLSERV    N  N    NetWare Lite 1.1 Server (SERVER.EXE)
0202h    WINICE        Y  Y    SoftICE/W
0203h    VCLIENT        N  Y    NetWare Lite 1.1+ Client
0205h    VCAFT        N  N    Novell Virtual CAFT Driver (LANalyzer for Win)
0206h    VTXRX        N  N    Novell Virtual TXRX Driver (LANalyzer for Win)
0234h    VCOMMUTE    Y  Y    PC Tools Commute
0442h    VTDAPI        N  Y    MMSys Win386 VTAPI Device
0444h    VADMAD            Autoinitialize DMA (Windows 3.0)
0445h    VSBD        Y  Y    WinResKit: Sound Blaster Device
0460h    UNIMODEM    N  Y
0483h    VSHARE        N  N    Windows for Workgroups Virtual SHARE
0484h    IFSMgr        Y  N    (Chicago) installable file system manager
0486h    VFAT        Y  Y    (Chicago)
048Bh    VCACHE        Y  Y
1021h    VMB        Y  Y    Microsoft C/C++ 7.00 WXSRVR
1022h    Vpfd        Y  Y    Microsoft C/C++ 7.00
1025h    MMD        Y  Y    Microsoft C/C++ 8.00, Visual C/C++ 1.00
21EAh    VADLIBWD    N  Y    Adlib Waveform Driver by John Ridges
2200h    VFINTD        Y  Y    Norton VFINTD (Norton Desktop)
2402h    ZMAX        N  N    Qualitas 386MAX v7 DOSMAX handler
24A0h    VNSS        N  Y    Norton Screen Saver (Norton Desktop)
24A1h    VNDWD        Y  Y    Norton VNDWD Device (Norton Desktop)
2640h    VASBID        N  Y    WinResKit: Artisoft Sounding Board Device
2860h    COMMTASK   N    N  Y    Windows 386-mode preemptive tasker by James
                A. Kenemuth of Interabang Computing
28C0h    VXD       N    Y  Y    Generic VxD for real and protected mode by
                Andrew Schulman in MSJ February 1993
292Dh    VSBPD        Y  Y    Sound Blaster Pro
3098h    VstlthD       N    N  N    for QEMM Stealth ROM mode
310eh    WPS        N  N    MS DevNet CD-ROM: Windows Process Status
7FE0h    VWFD       N    Y  Y    ??? by Neil Sandlin of Microsoft
7FE1h    VWATCHD       N    Y  Y    basic driver w/ no functionality except tracing
                by Keith Jin of Microsoft PSS
7FE5h    VFINTD       N    Y  Y    Virtual Floppy Interrupt trapper by Neil
                Sandlin of Microsoft
7FE7h    VMPAGES       N    Y  Y    demonstration of exporting VxD services, by
                Neil Sandlin of Microsoft
7FE9h    VIdleD       N    N  N    demonstration of Call_When_Idle function, by
                Bernie McIlroy of Microsoft
7FEBh    VMIOD       N    N  N    Virtual Monitor I/O Traffic Device, by Neil
                Sandlin of Microsoft
7FEDh    VMIRQD       N    N  N    Virtual Monitor IRQ Traffic Device, by Neil
                Sandlin of Microsoft
Note:    The high bit of the VxD ID is reserved for future use. The
    next 10 bits are the OEM # which is assigned by Microsoft. The
    low 5 bits are the device number.  Naturally, this scheme has not
    been adhered to since there are now more than 32 different VxDs.

Call VTD.386 entry point with:
    AX = 0000h get VTD version number
        Return: AH = major version
            AL = minor version
    AX = 0100h get current clock tick time
        Return: EDX:EAX = clock tick time in 840ns units since Windows was
                started
    AX = 0101h get current system time in milliseconds
        Return: EAX = time in milliseconds that Windows has been running
    AX = 0102h get current virtual machine time
        Return: EAX = cumulative amount of time the virtual machine has
            been active, in milliseconds
Note:    should only be called directly when TOOLHELP.DLL TimerCount() cannot
      be called

Call VADMAD entry point with:
    DX = operation
        0000h set VADMAD mode
        AX = desired mode
        0001h set VADMAD channel
        AX = desired channel
Note:    after setting mode/channel, start the DMA operation with an OUT to
      I/O port 0Bh (channels 0-3) or D6h (channels 4-7)
--------W-2F1685-----------------------------
INT 2F - MS Windows - SWITCH VMs AND CALLBACK
    AX = 1685h
    BX = VM ID of virtual machine to switch to
    CX = flags
        bit 0 wait until interrupts enabled
        bit 1 wait until critical section unowned
        bits 2-15 reserved (zero)
    DX:SI = priority boost (see VMM.INC)
    ES:DI -> FAR procedure to callback
Return: CF set on error
        AX = error code
        01h invalid VM ID
        02h invalid priority boost
        03h invalid flags
    CF clear if successful
        event will be or has been called
Notes:    some DOS devices, such as networks, need to call functions in a
      specific VM. This call forces the appropriate VM to be installed.
    the callback procedure must preserve all registers and return with IRET
SeeAlso: AX=1683h,INT 15/AX=1117h
--------E-2F1686-----------------------------
INT 2F - DOS Protected-Mode Interface - DETECT MODE
    AX = 1686h
Return: AX = 0000h if operating in protected mode under DPMI (INT 31 available)
    AX nonzero if in real/V86 mode or no DPMI (INT 31 not available)
SeeAlso: AX=1687h
--------E-2F1687-----------------------------
INT 2F - DOS Protected-Mode Interface - INSTALLATION CHECK
    AX = 1687h
Return: AX = 0000h if installed
        BX = flags
        bit 0: 32-bit programs supported
        CL = processor type (02h=80286, 03h=80386, 04h=80486)
        DH = DPMI major version
        DL = two-digit DPMI minor version (binary)
        SI = number of paragraphs of DOS extender private data
        ES:DI -> DPMI mode-switch entry point
    AX nonzero if not installed
SeeAlso: AX=1686h,AX=43E0h,AX=DE01h/BX=4450h,AX=FB42h/BX=0001h
SeeAlso: INT 31/AX=0400h,INT 31/AX=5702h,INT 38/AH=10h

Call mode switch entry point with:
    AX = flags
        bit 0: set if 32-bit program
    ES = real mode segment of buffer for DPMI private data (ignored if
        SI was zero)
Return: CF set on error
        program still in real mode
        AX = error code (DPMI 1.0+)
           8011h unable to allocate all necessary descriptors
           8021h 32-bit program specified, but 16-bit DPMI host
    CF clear if successful
        CS = 16-bit selector corresponding to real-mode CS
        SS = selector corresponding to real-mode SS (64K limit)
        DS = selector corresponding to real-mode DS (64K limit)
        ES = selector to program's PSP (100h byte limit)
        FS = GS = 0
        high word of ESP = 0 if 32-bit program
        program now in protected mode
Note:    this entry point is only called for the initial switch to protected
      mode
--------W-2F1688-----------------------------
INT 2F U - MS Windows 3.0, 386MAX v6.01 - GET SELECTOR TO LDT
    AX = 1688h
Return: AX = status??? (0000h for 386MAX)
    BX = selector for ???
--------W-2F1689-----------------------------
INT 2F U - MS Windows 3.0+ - KERNEL IDLE CALL
    AX = 1689h
    ???
Return: ???
SeeAlso: AX=1680h,INT 15/AX=1000h,INT 28
--------E-2F168A-----------------------------
INT 2F - DPMI 0.9+ - GET VENDOR-SPECIFIC API ENTRY POINT
    AX = 168Ah
    DS:(E)SI = selector:offset of ASCIZ vendor name
Return: AL = status
        00h successful
           ES:(E)DI -> extended API entry point
        8Ah unsuccessful
Notes:    the vendor name is used to determine which entry point to return; it is
      case-sensitive
    available in protected mode only
    32-bit applications use ESI and EDI, 16-bit applications use SI and DI
    this call is present but not documented for DPMI 0.9
    the Borland C++ 3.1 DPMILOAD does not handle requests for entry points
      other than the MS-DOS one gracefully, producing an unhandled
      exception report; this has been fixed in the Borland Pascal 7 version
SeeAlso: INT 31/AX=0A00h,INT 31/AH=57h

Vendor names:
 "MS-DOS"    ??? and 386MAX v6.00+
 "386MAX"    386MAX v6.00+
 "HELIX_DPMI"    Helix Netroom's DPMI server
 "Phar Lap"    Phar Lap 286|DOS-Extender RUN286

Call Phar Lap RUN286 entry point with:
    AX = 0000h (function "load MSW")
    BX = new value for MSW register (low word of CR0)
Return: ???
--------W-2F168B-----------------------------
INT 2F - MS Windows 3.1 - SET FOCUS TO SPECIFIED VIRTUAL MACHINE
    AX = 168Bh
    BX = virtual machine ID (see AX=1683h)
Return: AL = 00h if focus set to specified VM
Note:    documented on the Microsoft Developer's Network CD-ROM
SeeAlso: AX=1683h
--------W-2F168C-----------------------------
INT 2F - MS Windows 3.1 - RESTART COMMAND
    AX = 168Ch
    ???
Return: ???
Note:    WIN.COM executes specified application
--------W-2F1700-----------------------------
INT 2F - MS Windows "WINOLDAP" - IDENTIFY WinOldAp VERSION
    AX = 1700h
Return: AX = 1700h if this version of WINOLDAP doesn't support clipboard
    AX <> 1700h
        AL = WINOLDAP major version
        AH = WINOLDAP minor version
Program: WinOldAp (WINOLDAP.MOD) is a Microsoft Windows extension supporting
      "old" (character-mode) application access to Dynamic Data Exchange,
      menus, and the Windows clipboard.
Note:    this installation check DOES NOT follow the format used by other
      software of returning AL=FFh
Index:    installation check;WINOLDAP
--------W-2F1701-----------------------------
INT 2F - MS Windows "WINOLDAP" - OPEN CLIPBOARD
    AX = 1701h
Return: AX <> 0     success
    AX = 0     clipboard is already open
--------W-2F1702-----------------------------
INT 2F - MS Windows "WINOLDAP" - EMPTY CLIPBOARD
    AX = 1702h
Return: AX <> 0     clipboard has been emptied
    AX = 0     failure
--------W-2F1703-----------------------------
INT 2F - MS Windows "WINOLDAP" - SET CLIPBOARD DATA
    AX = 1703h
    DX = clipboard format supported by WinOldAp:
        01h text
        02h bitmap
        03h metafile picture
        04h SYLK
        05h DIF
        06h TIFF
        07h OEM text
        81h DSP text
        82h DSP bitmap
    ES:BX -> data (see below)
    SI:CX = size of data
Return: AX <> 0 data copied into the Clipboard
    AX = 0 failure

Format of bitmap:
Offset    Size    Description
 00h    WORD    type (0000h)
 02h    WORD    width of bitmap in pixels
 04h    WORD    height of bitmap in pixels
 06h    WORD    bytes per line
 08h    BYTE    number of color planes
 09h    BYTE    number of adjacent color bits in pixel
 0Ah    DWORD    pointer to start of data
 0Eh    WORD    width in 0.1mm units
 10h    WORD    height in 0.1mm units
 12h  N BYTEs    bitmap data

Format of metafile picture:
Offset    Size    Description
 00h    WORD    mapping mode
 02h    WORD    X extent
 04h    WORD    Y extent
 06h    WORD    picture data
--------W-2F1704-----------------------------
INT 2F - MS Windows "WINOLDAP" - GET CLIPBOARD DATA SIZE
    AX = 1704h
    DX = clipboard format supported by WinOldAp (see AX=1703h)
Return:     DX:AX = size of data in bytes, including any headers
Failure: DX:AX = 0  no data in this format in the Clipboard
--------W-2F1705-----------------------------
INT 2F - MS Windows "WINOLDAP" - GET CLIPBOARD DATA
    AX = 1705h
    DX = clipboard format supported by WinOldAp (see AX=1703h)
    ES:BX -> buffer
Return: AX <> 0     success
    AX = 0     error, or no data in this format in Clipboard
--------W-2F1708-----------------------------
INT 2F - MS Windows "WINOLDAP" - CloseClipboard
    AX = 1708h
Return: AX <> 0 success
    AX = 0 failure
--------W-2F1709-----------------------------
INT 2F - MS Windows "WINOLDAP" - COMPACT CLIPBOARD
    AX = 1709h
    SI:CX = desired size in bytes
Return: DX:AX = number of bytes in largest block of free memory
Note:    WinOldAp is responsible for including the size of any headers
--------W-2F170A-----------------------------
INT 2F - MS Windows "WINOLDAP" - GET DEVICE CAPABILITIES
    AX = 170Ah
    DX = GDI information index
        00h device driver version
        02h device classification
        04h width in mm
        06h height in mm
        08h width in pixels
        0Ah height in pixels
        0Ch bits per pixel
        0Eh number of bit planes
        10h number of brushes supported by device
        12h number of pens supported by device
        14h number of markers supported by device
        16h number of fonts supported by device
        18h number of colors
        1Ah size required for device descriptor
        1Ch curve capabilities
        1Eh line capabilities
        20h polygon capabilities
        22h text capabilities
        24h clipping capabilities
        26h bitblt capabilities
        28h X aspect
        2Ah Y aspect
        2Ch length of hypotenuse of aspect
        58h logical pixels per inch of width
        5Ah logical pixels per inch of height
Return:     AX = integer value of the desired item (see below)
Note:  This function returns the device-capability bits for the given display

Values for device classification:
 00h    vector plotter
 01h    raster display
 02h    raster printer
 03h    raster camera
 04h    character-stream, PLP
 05h    Metafile, VDM
 06h    display-file

Bitfields for curve capabilities:
 bit 0    circles
 bit 1    pie wedges
 bit 2    chord arcs
 bit 3    ellipses
 bit 4    wide lines
 bit 5    styled lines
 bit 6    wide styled lines
 bit 7    interiors

Bitfields for line capabilities:
 bit 1    polylines
 bit 2    markers
 bit 3    polymarkers
 bit 4    wide lines
 bit 5    styled lines
 bit 6    wide styled lines
 bit 7    interiors

Bitfields for polygon capabilities:
 bit 0    polygons
 bit 1    rectangles
 bit 2    trapezoids
 bit 3    scanlines
 bit 4    wide borders
 bit 5    styled borders
 bit 6    wide styled borders
 bit 7    interiors

Bitfields for text capabilities:
 bit 0    output precision character
 bit 1    output precision stroke
 bit 2    clippping precision stroke
 bit 3    90-degree character rotation
 bit 4    arbitrary character rotation
 bit 5    independent X and Y scaling
 bit 6    double-size
 bit 7    integer scaling
 bit 8    continuous scaling
 bit 9    bold
 bit 10 italic
 bit 11 underline
 bit 12 strikeout
 bit 13 raster fonts
 bit 14 vector fonts
 bit 15 reserved

Values for clipping capabilities:
 00h    none
 01h    clipping to rectangles

Bitfields for raster capabilities:
 bit 0    simple bitBLT
 bit 1    device requires banding support
 bit 2    device requires scaling support
 bit 3    supports >64K bitmap
----------2F18-------------------------------
INT 2F U - MS-Manager
    AH = 18h
    ???
Return: ???
--------l-2F1900-----------------------------
INT 2F U - DOS 4.x only SHELLB.COM - INSTALLATION CHECK
    AX = 1900h
Return: AL = 00h  not installed
         FFh  installed
--------l-2F1901BL00-------------------------
INT 2F U - DOS 4.x only SHELLB.COM - SHELLC.EXE INTERFACE
    AX = 1901h
    BL = 00h if SHELLC transient
         01h if SHELLC resident
    DS:DX -> far call entry point for resident SHELLC.EXE
Return: ES:DI -> SHELLC.EXE workspace within SHELLB.COM
Note:    SHELLB.COM and SHELLC.EXE are parts of the DOS 4.x shell
--------l-2F1902-----------------------------
INT 2F U - DOS 4.x only SHELLB.COM - COMMAND.COM INTERFACE
    AX = 1902h
    ES:DI -> ASCIZ full filename of current batch file, with at least the
         final filename element uppercased
    DS:DX -> buffer for results
Return: AL = 00h  failed, either
          (a) final filename element quoted at ES:DI does not match
              identity of shell batch file quoted as parameter of most
              recent call of SHELLB command, or
          (b) no more Program Start Commands available.
    AL= FFh     success, then:
        memory at DS:[DX+1] onwards filled as:
        DX+1:    BYTE    count of bytes of PSC
        DX+2: N BYTEs    Program Start Command text
            BYTE    0Dh terminator
Explanation: COMMAND.COM executes the result of this call in preference to
    reading a command from a batch file. Thus the batch file does not
    advance in execution for so long as SHELLB provides PSCs from its
    workspace. The PSCs are planted in SHELLB workspace by SHELLC, the user
    menu interface. The final PSC of a sequence is finished with a
    GOTO COMMON, which causes a loop back in the batch file which called
    SHELLC so as to execute SHELLC again. The check on batch file name
    permits PSCs to CALL nested batch files while PSCs are still stacked
    up for subsequent execution.
--------l-2F1903-----------------------------
INT 2F U - DOS 4.x only SHELLB.COM - COMMAND.COM interface
    AX = 1903h
    ES:DI -> ASCIZ batch file name as for AX=1902h
Return: AL = FFh if quoted batch file name matches last SHELLB parameter
    AL = 00h if it does not
--------l-2F1904-----------------------------
INT 2F U - DOS 4.x only SHELLB.COM - SHELLB transient to TSR intrface
    AX = 1904h
Return: ES:DI -> name of current shell batch file:
        WORD    number of bytes of name following
        BYTEs    (8 max) uppercase name of shell batch file
--------V-2F1A00-----------------------------
INT 2F - DOS 4+ ANSI.SYS - INSTALLATION CHECK
    AX = 1A00h
Return: AL = FFh if installed
Notes:    AVATAR.SYS also responds to this call
    documented for DOS 5+, but undocumented for DOS 4.x
--------V-2F1A00BX414E-----------------------
INT 2F - ANSIPLUS.SYS - INSTALLATION CHECK
    AX = 1A00h
    BX = 414Eh ('AN')
    CX = 5349h ('SI')
    DX = 2B2Bh ('++')
Return: AL = FFh if installed
        CF clear
        ES:BX -> INT 29 entry point
Program: ANSIPLUS.SYS is a CON device driver by Kristofer Sweger which
      replaces the normal ANSI.SYS is a more powerful version with many
      additional features
Note:    ANSIPLUS also identifies itself as ANSI.SYS if BX,CX, or DX differ
      from the magic values above
--------V-2F1A00BX4156-----------------------
INT 2F - AVATAR.SYS - INSTALLATION CHECK
    AX = 1A00h
    BX = 4156h ('AV')
    CX = 4154h ('AT')
    DX = 4152h ('AR')
Return: AL = FFh if installed
        CF clear
        BX = AVATAR protocol level supported
        CX = driver type
        0000h AVATAR.SYS
        4456h DVAVATAR.COM inside DESQview window
        DX = 0016h
Program: AVATAR.SYS is a CON replacement by George Adam Stanislav which
      interprets AVATAR command codes in the same way that ANSI interprets
      ANSI command codes
Notes:    AVATAR also identifies itself as ANSI.SYS if BX, CX, or DX differ from
      the magic values
--------V-2F1A01-----------------------------
INT 2F U - DOS 4+ ANSI.SYS internal - GET/SET DISPLAY INFORMATION
    AX = 1A01h
    CL = function
        7Fh for GET
        5Fh for SET
    DS:DX -> parm block as for INT 21,AX=440Ch,CX=037Fh/035Fh respectively
Return: CF set on error
        AX = error code (many non-standard)
    CF clear if successful
        AX destroyed
Note:    presumably this is the DOS IOCTL interface to ANSI.SYS
SeeAlso: AX=1A02h,INT 21/AX=440Ch
--------V-2F1A02-----------------------------
INT 2F U - DOS 4+ ANSI.SYS internal - MISCELLANEOUS REQUESTS
    AX = 1A02h
    DS:DX -> parameter block (see below)
Note:    DOS 5+ chains to previous handler if AL > 02h on call
SeeAlso: AX=1A01h

Format of parameter block:
Offset    Size    Description
 00h    BYTE    subfunction
        00h set/reset interlock
        01h get /L flag
 01h    BYTE    interlock state
        00h=reset, 01h=set
          This interlock prevents some of the ANSI.SYS post-processing
          in its hook onto INT 10, AH=00h mode set
 02h    BYTE    (returned)
        00h if /L not in effect
        01h if /L in effect
--------V-2F1A21-----------------------------
INT 2F - AVATAR.SYS - SET DRIVER STATE
    AX = 1A21h (AL='!')
    DS:SI -> command string with one or more state characters
    CX = length of command string
Return: CF set on error (invalid subfunction)
    CF clear if successful
Note:    the characters in the state string are interpreted left to right, and
      need not be in any particular order
SeeAlso: AX=1A3Fh

Values for state characters:
 'a'    activate driver
 'd'    disable driver
 'f'    use fast screen output
 'g'    always convert gray keys (+ and -) to function keys
 'G'    never convert gray keys
 'l'    convert gray keys only when ScrollLock active
 's'    use slow screen output
 't'    Tandy 1000 keyboard (not yet implemented)
--------V-2F1A3C-----------------------------
INT 2F U - AVATAR.SYS v0.11 - ???
    AX = 1A3Ch
    ???
Return: CX = 0000h
--------V-2F1A3E-----------------------------
INT 2F U - AVATAR.SYS v0.11 - ???
    AX = 1A3Eh
    CL = ???
    CH = ???
    DL = ???
    DH = ???
Return: CL = ???
    CH = ???
    DL = ???
    DH = ???
--------V-2F1A3F-----------------------------
INT 2F - AVATAR.SYS - QUERY DRIVER STATE
    AX = 1A3Fh (AL='?')
    ES:DI -> buffer
    CX = length of buffer in bytes
Return: CF clear
    CX = actual size of returned info
Note:    the returned information consists of multiple letters whose meanings
      are described under AX=1A21h
SeeAlso: AX=1A21h
--------S-2F1A42BX4156-----------------------
INT 2F - AVATAR Serial Dispatcher - INSTALL IRQ3 HANDLER
    AX = 1A42h
    BX = 4156h ('AV')
    ES:DI -> FAR handler for serial port using IRQ3
    DS = data segment needed by handler
Return: AX = 1A42h if ASD not installed
       = 0000h if no more room
       else handle to use when uninstalling
Notes:    the handler need not save/restore registers or signal EOI to the
      interrupt controller
    the handler should return AX=0000h if the interrupt was meant for it,
      and either leave AX unchanged or return a non-zero value otherwise
    the most recently installed handler will be called first, continuing
      to earlier handlers until one returns AX=0000h
SeeAlso: AX=1A43h,AX=1A62h
--------S-2F1A43BX4156-----------------------
INT 2F - AVATAR Serial Dispatcher - INSTALL IRQ4 HANDLER
    AX = 1A43h
    BX = 4156h ('AV')
    ES:DI -> FAR handler for serial port using IRQ4
    DS = data segment needed by handler
Return: AX = 1A43h if ASD not installed
       = 0000h if no more room
       else handle to use when uninstalling
Notes:    (see AX=1A42h)
SeeAlso: AX=1A42h,AX=1A63h
--------V-2F1A44BX4156-----------------------
INT 2F - AVATAR.SYS v0.11+ - GET DATA SEGMENT
    AX = 1A44h
    BX = 4156h ('AV')
Return: AX = 0000h
    DS = data segment
    CX = size of data segment
Note:    AVATAR.SYS calls this function whenever it is invoked.    If each
      process under a multitasker hooks this function and provides a
      separate data segment, AVATAR.SYS becomes fully reentrant.
SeeAlso: AX=1A21h,AX=1A3Fh
--------V-2F1A52-----------------------------
INT 2F U - AVATAR.SYS v0.11 - GET ???
    AX = 1A52h
    CX = size of buffer
    ES:DI -> buffer
Return: ??? copied into user buffer
Note:    the maximum size of the data which may be copied is returned by
      AX=1A72h
SeeAlso: AX=1A72h
--------V-2F1A53-----------------------------
INT 2F U - AVATAR.SYS v0.11 - ???
    AX = 1A53h
    CL = ??? (00h-05h)
    ???
Return: ???
--------S-2F1A62BX4156-----------------------
INT 2F - AVATAR Serial Dispatcher - UNINSTALL IRQ3 HANDLER
    AX = 1A62h
    BX = 4156h ('AV')
    CX = handle for IRQ routine returned by AX=1A42h
SeeAlso: AX=1A42h,AX=1A63h
--------S-2F1A63BX4156-----------------------
INT 2F - AVATAR Serial Dispatcher - UNINSTALL IRQ4 HANDLER
    AX = 1A63h
    BX = 4156h ('AV')
    CX = handle for IRQ routine returned by AX=1A43h
SeeAlso: AX=1A43h,AX=1A62h
--------V-2F1A72-----------------------------
INT 2F U - AVATAR.SYS v0.11 - GET ??? SIZE
    AX = 1A72h
Return: CX = maximum size of ???
SeeAlso: AX=1A52h
--------V-2F1A7B-----------------------------
INT 2F U - AVATAR.SYS v0.11 - ???
    AX = 1A7Bh
Return: AX = 0000h
    CX = 0000h
--------V-2F1A7D-----------------------------
INT 2F U - AVATAR.SYS v0.11 - ???
    AX = 1A7Dh
Return: AX = ???
--------V-2F1AADDX0000-----------------------
INT 2F U - AVATAR.SYS v0.11 - ???
    AX = 1AADh
    DX = 0000h
    CX = subfunction (00h-0Ch)
    ???
Return: AX = 0000h if DX was nonzero
    ???
--------m-2F1B00-----------------------------
INT 2F U - DOS 4+ XMA2EMS.SYS extension internal - INSTALLATION CHECK
    AX = 1B00h
Return: AL = FFh if installed
Note:    XMA2EMS.SYS extension is only installed if DOS has page frames to hide.
    This extension hooks onto INT 67/AH=58h and returns from that call data
      which excludes the physical pages being used by DOS.
SeeAlso: AH=1Bh"FRAME INFO"
--------m-2F1B-------------------------------
INT 2F U - DOS 4+ XMA2EMS.SYS extension internal - GET HIDDEN FRAME INFORMATION
    AH = 1Bh
    AL <> 00h
    DI = hidden physical page number
Return: AX = FFFFh if failed (no such hidden page)
    AX = 0000h if OK, then
         ES = segment of page frame
         DI = physical page number
Notes:    this corresponds to the data edited out of the INT 67/AH=58h call
    FASTOPEN makes this call with AL = FFh
SeeAlso: AX=1B00h
--------V-2F2300-----------------------------
INT 2F - DR-DOS 5.0 GRAFTABL - INSTALLATION CHECK
    AX = 2300h
Return: AH = FFh
Note:    this installation check does not follow the usual format
SeeAlso: AH=23h
--------V-2F23-------------------------------
INT 2F - DR-DOS 5.0 GRAFTABL - GET GRAPHICS DATA
    AH = 23h
    AL nonzero
Return: AH = FFh
    ES:BX -> graphics data
SeeAlso: AX=2300h
--------T-2F2700-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - INSTALLATION CHECK
    AX = 2700h
Return: AL = 00h not installed
       = FFh installed
--------T-2F2701-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - GET STATUS
    AX = 2701h
Return: AX = maximum simultaneous tasks
    BX = index into TASK_IDS of current foreground task
    CX = currently-active tasks
    DX = version number (DR-DOS 6.0 = 0001h)
    ES:SI -> TASK_IDS
    ES:DI -> name table (array of 8-byte names, NUL-terminated if <8 chars)
Notes:    do not attempt to create a new task if CX == AX
    the task's index is its position on the task menu, while its ID is the
      position within the internal task name table
SeeAlso: AX=2714h,AX=2716h
--------T-2F2702-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - GET PER-TASK EMS LIMIT
    AX = 2702h
Return: DX = maximum pages INT 67/AH=42h will report available
Note:    TaskMAX does not limit EMS allocations other than by limiting the
      amount which is reported as being available at a given time
SeeAlso: AX=2703h,INT 67/AH=42h
--------T-2F2703-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - SET PER-TASK EMS LIMIT
    AX = 2703h
    DX = maximum pages INT 67/AH=42h should report available
Return: DX = new maximum for reporting
SeeAlso: AX=2702h,INT 67/AH=42h
--------T-2F2704-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - REGISTER/UNREGISTER TASK MANAGER
    AX = 2704h
    DL = subfunction
        00h unregister task manager
        01h register task manager
Return: DL = status
        00h registered
        01h unregistered
Notes:    a task manager replaces TaskMAX's menu system with its own user
      interface; while one is registered, the TaskMAX hotkeys and
      Ctrl-Alt-Del invoke the manager rather than the built-in menu system
    unregister the task manager before terminating it
SeeAlso: AX=2705h
Index:    hotkeys;TaskMAX
--------T-2F2705-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - ENABLE/DISABLE DIRECT SWITCHING
    AX = 2705h
    DL = subfunction
        00h disable keystrokes for switching to next/prev/specified task
        01h enable
Return: nothing
Note:    should only be called by a registered task manager (see AX=2704h)
SeeAlso: AX=2704h,AX=2706h
--------T-2F2706-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - SWITCH TO SPECIFIED TASK
    AX = 2706h
    DX = task index (see AX=2701h) of task to be activated
Return: DX = task index of previously-active task
SeeAlso: AX=2705h,AX=2707h,AX=2715h
--------T-2F2707-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - CREATE NEW TASK
    AX = 2707h
    DS:DX -> ASCIZ pathname of executable
    ES:BX -> parameter block (see below)
    CX = number of ticks before automatic return to task manager
        (0000h = run until termination or explicitly switched)
Return: DX = new task's task index (FFFFh if task terminated)
SeeAlso: AX=2706h,AX=2708h

Format of parameter block:
Offset    Size    Description
 00h    WORD    reserved, should be 0000h
 02h    DWORD    pointer to command tail to be copied into child's PSP
 06h    DWORD    pointer to first FCB to be copied into child's PSP
 0Ah    DWORD    pointer to second FCB to be copied into child's PSP
--------T-2F2708-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - DELETE TASK
    AX = 2708h
    DX = task index
Return: DX = FFFFh (task deleted)
Notes:    this call should only be used for abnormal task termination, after
      first checking for open files with AX=270Ch; should not be used
      with programs that allocate EMS or XMS memory
    switches to specified task first
SeeAlso: AX=2707h
--------T-2F2709-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - NAME TASK
    AX = 2709h
    DX = task index
    DS:SI -> 8-byte name (8 NULs = remove name)
Return: AL = task flags
        00h ID unused or task terminated
        01h ID in use, task name table entry valid
        81h ID in use, task name fixed
    BX = task ID
    ES:DI -> name in task name table (see AX=2701h)
Note:    the task retains the given name until it terminates or the name is
      removed by specifying a name of 8 NULs.
SeeAlso: AX=2701h,AX=2707h
--------T-2F270A-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - CONVERT TASK INDEX TO TASK ID
    AX = 270Ah
    DX = task index
Return: DX = task ID (FFFFh if index invalid)
Note:    task IDs stay constant, while indexes can change when other tasks are
      deleted
SeeAlso: AX=2701h,AX=270Bh
--------T-2F270B-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - CONVERT TASK ID TO TASK INDEX
    AX = 270Bh
    DX = task ID
Return: DX = task index (FFFFh if task not active)
SeeAlso: AX=270Ah
--------T-2F270C-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - CHECK OPEN FILES
    AX = 270Ch
    DX = task index
Return: AX = number of files currently open for specified task
SeeAlso: AX=2708h
--------T-2F270D-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - CHECK IF TASK RUNNING PRIMARY COMMAND INTERPRETER
    AX = 270Dh
    DX = task index
Return: DX = status
        0000h if primary command interpreter (COMMAND.COM, etc.) running
        0001h if not in root shell for task
Note:    TaskMAX will return 0001h if the specified task has spawned another
      command interpreter with AX=2707h
SeeAlso: AX=2707h,AX=270Ch
--------T-2F270E-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - GET/SET TEXT PASTE LEAD-IN
    AX = 270Eh
    CX = length of string (max 15 keystrokes, 0000h to get current string)
    DS:SI -> pasting lead-in string (character/scan-code pairs)
Return: ES:DI -> current lead-in string
Note:    the specified sequence of keystrokes is sent to the application before
      every line of a text-mode spreadsheet paste
SeeAlso: AX=270Fh,AX=2710h,AX=2713h
--------T-2F270F-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - GET/SET NUMERIC PASTE LEAD-IN
    AX = 270Fh
    CX = length of string (max 15 keystrokes, 0000h to get current string)
    DS:SI -> pasting lead-in string (character/scan-code pairs)
Return: ES:DI -> current lead-in string
Note:    the specified sequence of keystrokes is sent to the application before
      every number in a numeric-mode spreadsheet paste
SeeAlso: AX=270Eh,AX=2710h,AX=2711h,AX=2713h
--------T-2F2710-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - GET/SET PASTE LINE TERMINATOR STRING
    AX = 2710h
    CX = length of string (max 15 keystrokes, 0000h to get current string)
    DS:SI -> pasting terminator string (character/scan-code pairs)
Return: ES:DI -> current terminator string
Note:    the specified sequence of keystrokes is sent to the application after
      every line of a spreadsheet paste operation
SeeAlso: AX=270Eh,AX=270Fh,AX=2713h
--------T-2F2711-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - GET/SET NUMERIC PASTE DECIMAL POINT
    AX = 2711h
    DX = ASCII code for separator (FFFFh to get current)
Return: DL = current separator character
SeeAlso: AX=270Fh
--------T-2F2712-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - INITIATE EXPORTING TASK DATA
    AX = 2712h
    DX = task index
--------T-2F2713-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - INITIATE PASTE OPERATION
    AX = 2713h
    DX = task index
    CX = paste mode
        0000h alphanumeric
        0001h numeric
        0002h text
SeeAlso: AX=270Eh,AX=270Fh,AX=2710h,AX=2711h
--------T-2F2714-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - GET SWAP SPACE INFO
    AX = 2714h
Return: CX = total KB of swap space
    DX = available KB of swap space
SeeAlso: AX=2701h
--------T-2F2715-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - SWITCH TO TASK MANAGER
    AX = 2715h
Return: only after calling task is again selected
SeeAlso: AX=2706h
--------T-2F2716-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - GET PASTE BUFFER STATUS
    AX = 2716h
Return: AX = 0000h if AX=2716h,AX=2717h,AX=2718h supported
        CX = bytes in paste buffer
        DX = current generation number (updated after every copy operation)
SeeAlso: AX=2701h,AX=2713h,AX=2714h,AX=2717h,AX=2718h
--------T-2F2717-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - PASTE DATA DIRECTLY TO APPLICATION BUFFER
    AX = 2717h
    CX = bytes in destination buffer
    ES:DI -> destination buffer
Return: AX = 0000h if function supported
        CX = bytes actually copied (FFFFh if buffer too small)
        DX = current generation number for paste buffer
Note:    the destination buffer may be too small if another task adds more data
      to the paste buffer after the AX=2716h call but before this call
SeeAlso: AX=2713h,AX=2716h,AX=2718h
--------T-2F2718-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - COPY DATA DIRECTLY INTO PASTE BUFFER
    AX = 2718h
    CX = bytes in source buffer
    DS:SI -> source buffer (plain ASCII, lines terminated with CR LF)
Return: AX = 0000h if function supported
        CX = bytes actually copied
        DX = current generation number for paste buffer
SeeAlso: AX=2712h,AX=2716h,AX=2717h
--------F-2F2A-------------------------------
INT 2F - Gammafax DOS Dispatcher INTERFACE
    AH = 2Ah
Note:    details not available at this time
SeeAlso: AX=8000h"FaxBIOS",AX=C000h"MTEZ",AX=CB00h,AX=CBDDh,INT 66"BitFax"
--------t-2F3900-----------------------------
INT 2F - Kingswood TSR INTERFACE - COMPATIBILITY MODE
    AX = 3900h
Return: AL = status
        00h not installed
        FFh one or more TSRs using this interface is installed
        DX may be destroyed
Note:    this function is provided to that the multiplex number will appear used
      to other programs
SeeAlso: AH=39h/BL=00h
--------t-2F39--BL00-------------------------
INT 2F - Kingswood TSR INTERFACE - INSTALLATION CHECK
    AH = 39h
    BL = 00h
    AL = TSR ID number (01h-FFh, currently only 01h-1Bh used) (see below)
Return: AL = status
        00h not installed
        FFh installed
        DX = segment address of resident module
Note:    All of Kingswood Software's TSRs use this interface.  Usually the
      resident module is installed by allocating a block of upper memory,
      setting its owner ID to 000Ah (used by DOS), and filling the MCB name
      field with the TSR's name.
SeeAlso: AX=3900h,AH=39h/BL=01h

Values for TSR ID number:
 01h    TSR Windows
 02h    NOBUSY
 03h    CD STACK
 04h    DISK WATCH
 05h    PUSHBP
 06h    ALIAS
 07h    KEYMACRO
 08h    SLOWDOWN
 09h    ANSIGRAB
 0Ah    TEE
 0Bh    FASTMOUS
 0Ch    EXTWILD
 0Dh    BREAKOUT
 0Eh    STOPDISK
 0Fh    MEMINIT
 10h    JANUSEXT
 11h    CAPS
 12h    ANSI
 13h    TRAPPER
 14h    EATMEM
 15h    WPJOKE
 16h    SHOWDOS
 17h    LOGINTS
 18h    BLANKVGA
 19h    SWAPEXEC
 1Ah    SHELL
 1Bh    TSRGAMES

Format of TSR modules:
Offset    Size    Description
 00h  4 BYTEs    signature "FTSR"
 04h    WORD    segment address of this module (used to check validity)
 06h    WORD    number of words to skip (usually 0000h if no PSP present)
 08h  N WORDs    module-defined data that must be at a fixed segment offset
        (usually only a PSP if file access is required)
     5N BYTEs    interrupt list (see below)
    BYTE    FFh terminator

Format of interrupt list entry:
Offset    Size    Description
 00h    BYTE    interrupt number (00h-FEh)
 01h    WORD    offset within segment of DWORD pointer to previous interrupt
 03h    WORD    offset within segment of begin of interrupt handler code
--------t-2F39--BL01-------------------------
INT 2F - Kingswood TSR INTERFACE - REMOVAL CHECK
    AH = 39h
    BL = 01h
    AL = TSR ID number (01h-FFh) (see AH=39h/BL=00h)
Return: AL = status
        00h not ready to be removed
        FFh resident module may be removed by deassigning the interrupts
        hooked by the TSR and deallocating the TSR's memory block
    AH,BX,CX,DX,ES may be destroyed
SeeAlso: AX=3900h,AH=39h/BL=00h
--------t-2F39-------------------------------
INT 2F - Kingswood TSR INTERFACE - APPLICATION-SPECIFIC FUNCTION CALLS
    AH = 39h
    BL = function number (02h-FFh)
    AL = TSR ID number (01h-FFh)
    CX,DX,SI,DI,DS,ES may contain parameters
    BH reserved for use by the function dispatcher
Return: as appropriate for the called function
SeeAlso: AX=3900h,AH=39h/BL=00h,AX=3901h/BL=02h
--------r-2F3901BL02-------------------------
INT 2F - Kingswood TSR Windows - OPEN WINDOW
    AX = 3901h
    BL = 02h
Return: AX = error code (0000h if successful)
    SI,DI,DS,ES preserved
Notes:    opens the next TSR window on top of any others.     Only three
      TSR windows can be opened at any one time.  The three windows
      are all 40x11 characters, partly overlapping.
SeeAlso: AH=39h/BL=00h,AX=3901h/BL=03h,AX=3901h/BL=05h,AX=3901h/BL=06h
--------r-2F3901BL03-------------------------
INT 2F - Kingswood TSR Windows - HIDE WINDOWS
    AX = 3901h
    BL = 03h
Return: AX = error code (0000h if successful)
    SI,DI,DS,ES preserved
Notes:    Hide any visible TSR windows from view.
SeeAlso: AH=39h/BL=00h,AX=3901h/BL=02h,AX=3901h/BL=05h
--------r-2F3901BL04-------------------------
INT 2F - Kingswood TSR Windows - SHOW WINDOWS
    AX = 3901h
    BL = 04h
Return: AX = error code (0000h if successful)
    SI,DI,DS,ES preserved
Notes:    Re-display all TSR windows after a HIDE WINDOWS call.
SeeAlso: AH=39h/BL=00h,AX=3901h/BL=02h,AX=3901h/BL=03h
--------r-2F3901BL05-------------------------
INT 2F - Kingswood TSR Windows - CLOSE WINDOW
    AX = 3901h
    BL = 05h
Return: AX = error code (0000h if successful)
    SI,DI,DS,ES preserved
Notes:    Close the last opened TSR window.
SeeAlso: AH=39h/BL=00h,AX=3901h/BL=02h
--------r-2F3901BL06-------------------------
INT 2F - Kingswood TSR Windows - SET WINDOW TITLE
    AX = 3901h
    BL = 06h
    DS:SI -> title string
Return: AX = error code (0000h if successful)
    SI,DI,DS,ES preserved
SeeAlso: AH=39h/BL=00h,AX=3901h/BL=02h
--------r-2F3901BL07-------------------------
INT 2F - Kingswood TSR Windows - POSITION CURSOR
    AX = 3901h
    BL = 07h
    CH = Y coordinate (0-10)
    CL = X coordinate (0-39)
Return: AX = error code (0000h if successful)
    SI,DI,DS,ES preserved
Note:    the hardware cursor is always disabled when a TSR window is opened;
      this call only sets a text position
SeeAlso: AH=39h/BL=00h,AX=3901h/BL=08h,AX=3901h/BL=09h
--------r-2F3901BL08-------------------------
INT 2F - Kingswood TSR Windows - DISPLAY STRING
    AX = 3901h
    BL = 08h
    DS:SI -> string
Return: AX = error code (0000h if successful)
    SI,DI,DS,ES preserved
Notes:    The text is not clipped.
    This routine understands Tab, NewLine and Carriage Return
SeeAlso: AH=39h/BL=00h,AX=3901h/BL=07h
--------r-2F3901BL09-------------------------
INT 2F - Kingswood TSR Windows - SCROLL WINDOW
    AX = 3901h
    BL = 09h
    CL = scroll direction: 01h up, FFh down, 00h clear window
Return: AX = error code (0000h if successful)
    SI,DI,DS,ES preserved
SeeAlso: AH=39h/BL=00h,AX=3901h/BL=07h
--------r-2F3901BL0A-------------------------
INT 2F - Kingswood TSR Windows - SOUND BEEPER
    AX = 3901h
    BL = 0Ah
    DX = sound divisor, or 0 for silence.
         (divide 1843200 by required frequency to get value for DX)
    CL = sound length in 18.2 Hz clock ticks
Return: AX = error code (0000h if successful)
    SI,DI,DS,ES preserved
SeeAlso: AH=39h/BL=00h
--------r-2F3901BL0B-------------------------
INT 2F - Kingswood TSR Windows - ADD OR REMOVE USER
    AX = 3901h
    BL = 0Bh
    CL = number of users increment: +1 if adding a new user
                    -1 if removing a user
Return: AX = error code (0000h if successful)
    SI,DI,DS,ES preserved
Note:    the TSR windows resident module may only be removed when the internal
      user count is zero
SeeAlso: AH=39h/BL=00h,AX=3901h/BL=02h
--------V-2F3912BL03-------------------------
INT 2F - Kingswood ANSI display driver - SET COMPATIBILITY MODE
    AX = 3912h
    BL = 03h
    CL = new mode (00h fast, FFh BIOS)
Return: AL = old compatibility mode
    SI,DI,DS,ES preserved
SeeAlso: AX=3900h,AX=3912h/BL=04h
--------V-2F3912BL04-------------------------
INT 2F - Kingswood ANSI display driver - SET FLAGS
    AX = 3912h
    BL = 04h
    CL = new flags
        bit 0: do not wrap at end of line
        bit 1: wait for beeps to end before displaying next character
        bit 2: do not use graphics cursor
Return: AL = old flags
    SI,DI,DS,ES preserved
SeeAlso: AX=3900h,AX=3912h/BL=03h
--------W-2F4000-----------------------------
INT 2F - Windows 3.x (OS/2 2.x???) - GET VIRTUAL DEVICE DRIVER (VDD) CAPABLTIES
    AX = 4000h
Return: AL = 01h does not virtualize video access
         02h virtualizes the video when in text mode
         03h virtualizes the video when in text mode or single plane
         graphics modes
         04h virtualizes the video when in text mode, single plane
         graphics modes, and VGA multiplane modes
         FFh virtualizes the video fully
Note:    this function is used by display drivers to find out what capabilities
      exist for the VDD driver and also trigger the VDD driver to call
      functions 4005h and 4006h.  This function also gives the Video Driver
      hardware access to the video registers.
--------O-2F4001-----------------------------
INT 2F C - OS/2 compatibility box - SWITCHING DOS TO BACKGROUND
    AX = 4001h
Note:    called by OS/2 when the DOS box is about to be placed in the background
      and the video driver should save any necessary state
SeeAlso: AX=4002h,AX=4005h
--------O-2F4002-----------------------------
INT 2F C - OS/2 compatibility box - SWITCHING DOS TO FOREGROUND
    AX = 4002h
Note:    called by OS/2 when the DOS box is about to be placed in the foreground
      and the video driver should restore the previously-saved state
SeeAlso: AX=4001h,AX=4006h
--------W-2F4003-----------------------------
INT 2F - Windows 3.x - ENTERING VIDEO DRIVER CRITICAL SECTION
    AX = 4003h
Note:    This critical section must be exited within 1 second.
SeeAlso: AX=4004h
--------W-2F4004-----------------------------
INT 2F - Windows 3.x - EXITING VIDEO DRIVER CRITICAL SECTION
    AX = 4004h
SeeAlso: AX=4003h
--------W-2F4005-----------------------------
INT 2F C - Windows 3.x - SWITCHING DOS TO BACKGROUND
    AX = 4005h
Note:    called by Windows when the DOS box is about to be placed in the
      background and the video driver should save any necessary state
      information (this may be called only in Standard mode)
SeeAlso: AX=4001h,AX=4006h
--------W-2F4006-----------------------------
INT 2F C - Windows 3.x - SWITCHING DOS TO FOREGROUND
    AX = 4006h
Note:    called by Windows when the DOS box is about to be placed in the
      foreground and the video driver should restore any necessary state
      information (this may be called only in Standard mode)
SeeAlso: AX=4002h,AX=4005h
--------W-2F4007-----------------------------
INT 2F - Windows 3.x - ENABLE VDD TRAPPING OF VIDEO REGISTERS
    AX = 4007h
Note:    used by Windows Standard mode
--------E-2F4040-----------------------------
INT 2F - PharLap 286|DOS-Extender Lite v2.5 - ???
    AX = 4040h
Return: BX:CX -> ???
--------N-2F4100-----------------------------
INT 2F - DOS Enhanced LAN Manager 2.0+ MINIPOP/NETPOPUP - INSTALLATION CHECK
    AX = 4100h
Return: CF clear if successful
        AL = FFh
    CF set on error
        AX = ???
Notes:    MINIPOP and NETPOPUP provide a network message popup service
    LAN Manager enhanced mode adds features beyond the standard redirector
      file/printer services
SeeAlso: AX=118Ah,AX=4103h,AX=4104h,AH=42h,AH=4Bh
--------N-2F4103-----------------------------
INT 2F - DOS Enhanced LAN Manager 2.0+ MINIPOP/NETPOPUP - ???
    AX = 4103h
Return: ???
SeeAlso: AX=4100h,AX=4104h
--------N-2F4104-----------------------------
INT 2F - DOS Enhanced LAN Manager 2.0+ MINIPOP/NETPOPUP - ???
    AX = 4104h
Return: ???
SeeAlso: AX=4100h,AX=4103h
--------N-2F42-------------------------------
INT 2F - LAN Manager 2.0 DOS Enhanced MSRV.EXE - MESSENGER SERVICE
    AH = 42h
    ???
Return: ???
Note:    LAN Manager enhanced mode adds features beyond the standard redirector
      file/printer services
SeeAlso: AX=118Ah,AX=4100h,AH=4Bh
--------m-2F4300-----------------------------
INT 2F - EXTENDED MEMORY SPECIFICATION (XMS) v2+ - INSTALLATION CHECK
    AX = 4300h
Return: AL = 80h XMS driver installed
    AL <> 80h no driver
Notes:    XMS gives access to extended memory and noncontiguous/nonEMS memory
      above 640K
    this installation check DOES NOT follow the format used by other
      software
SeeAlso: AX=4310h
Index:    installation check;XMS version 2+
--------m-2F4308-----------------------------
INT 2F U - HIMEM.SYS v2.77+ - GET A20 HANDLER NUMBER
    AX = 4308h
Return: AL = 43h if supported
        BL = A20 handler number (value of /MACHINE:nn switch)
        BH = AT A20 switch time (00h medium, 01h fast, 02h slow)
SeeAlso: AX=4309h,AX=4330h
--------m-2F4309-----------------------------
INT 2F U - HIMEM.SYS v3.09+ - GET XMS HANDLE TABLE
    AX = 4309h
Return: AL = 43h if function supported
        ES:BX -> XMS handle table (see below)
Note:    HIMEM.SYS v3.09 is part of MS-DOS 6.0.
SeeAlso: AX=4308h

Format of XMS handle table:
Offset    Size    Description
 00h    BYTE    ??? (01h in HIMEM.SYS v3.09)
 01h    BYTE    size of one handle??? (0Ah in HIMEM.SYS v3.09)
 02h    WORD    value of /numhandles= parameter (default = 20h)
 04h    DWORD    pointer to XMS handle array (see below)

Format of XMS handle [array]:
Offset    Size    Description
 00h    BYTE    flag 01h=free, 02h=used, 04h=unused
 01h    BYTE    lock count (00h=unlocked)
 02h    DWORD    address of XMS block in KB (shift left by 10 for abs. address)
 06h    DWORD    size of XMS block in KB
--------m-2F4310-----------------------------
INT 2F - EXTENDED MEMORY SPECIFICATION (XMS) v2+ - GET DRIVER ADDRESS
    AX = 4310h
Return: ES:BX -> driver entry point
Note:    HIMEM.SYS v2.77 chains to previous handler if AH is not 00h or 10h
SeeAlso: AX=4300h

Perform a FAR call to the driver entry point with AH set to the function code
    AH    function
    00h  Get XMS version number
         Return: AX = XMS version (in BCD, AH=major, AL=minor)
             BX = internal revision number
             DX = 0001h if HMA (1M to 1M + 64K) exists
              0000h if HMA does not exist
    01h  Request High Memory Area (1M to 1M + 64K)
         DX = memory in bytes (for TSR or device drivers)
          FFFFh if application program
         Return: AX = 0001h success
            = 0000h failure
               BL = error code (80h,81h,90h,91h,92h) (see below)
    02h  Release High Memory Area
         Return: AX = 0001h success
            = 0000h failure
               BL = error code (80h,81h,90h,93h) (see below)
    03h  Global enable A20, for using the HMA
         Return: AX = 0001h success
            = 0000h failure
               BL = error code (80h,81h,82h) (see below)
    04h  Global disable A20
         Return: AX = 0001h success
            = 0000h failure
               BL = error code (80h,81h,82h,94h) (see below)
    05h  Local enable A20, for direct access to extended memory
         Return: AX = 0001h success
            = 0000h failure
               BL = error code (80h,81h,82h) (see below)
    06h  Local disable A20
         Return: AX = 0001h success
            = 0000h failure
               BL = error code (80h,81h,82h,94h) (see below)
    07h  Query A20 state
         Return: AX = 0001h enabled
            = 0000h disabled
             BL = error code (00h,80h,81h) (see below)
    08h  Query free extended memory, not counting HMA
         BL = 00h (some implementations leave BL unchanged on success)
         Return: AX = size of largest extended memory block in KB
             DX = total extended memory in KB
             BL = error code (00h,80h,81h,A0h) (see below)
    09h  Allocate extended memory block
         DX = Kbytes needed
         Return: AX = 0001h success
               DX = handle for memory block
            = 0000h failure
               BL = error code (80h,81h,A0h) (see below)
    0Ah  Free extended memory block
         DX = handle of block to free
         Return: AX = 0001h success
            = 0000h failure
               BL = error code (80h,81h,A2h,ABh) (see below)
    0Bh  Move extended memory block
         DS:SI -> EMM structure (see below)
         Note: if either handle is 0000h, the corresponding offset is
           considered to be an absolute segment:offset address in
           directly addressable memory
         Return: AX = 0001h success
            = 0000h failure
               BL = error code (80h-82h,A3h-A9h) (see below)
    0Ch  Lock extended memory block
         DX = handle of block to lock
         Return: AX = 0001h success
               DX:BX = 32-bit linear address of locked block
            = 0000h failure
               BL = error code (80h,81h,A2h,ACh,ADh) (see below)
         Note: MS Windows 3.x rejects this function for handles allocated
            after Windows started
    0Dh  Unlock extended memory block
         DX = handle of block to unlock
         Return: AX = 0001h success
            = 0000h failure
               BL = error code (80h,81h,A2h,AAh) (see below)
    0Eh  Get handle information
         DX = handle for which to get info
         Return: AX = 0001h success
               BH = block's lock count
               BL = number of free handles left
               DX = block size in KB
            = 0000h failure
               BL = error code (80h,81h,A2h) (see below)
         BUG: MS Windows 3.10 acts as though unallocated handles are in use
         Note: MS Windows 3.00 has problems with this call
    0Fh  Reallocate extended memory block
         DX = handle of block
         BX = new size of block in KB
         Return: AX = 0001h success
            = 0000h failure
               BL = error code (80h,81h,A0h-A2h,ABh) (see below)
    10h  Request upper memory block (nonEMS memory above 640K)
         DX = size of block in paragraphs
         Return: AX = 0001h success
               BX = segment address of UMB
               DX = actual size of block
            = 0000h failure
               BL = error code (80h,B0h,B1h) (see below)
               DX = largest available block
    11h  Release upper memory block
         DX = segment address of UMB to release
         Return: AX = 0001h success
            = 0000h failure
               BL = error code (80h,B2h) (see below)
    12h  (XMS v3.0) Reallocate upper memory block
         DX = segment address of UMB to resize
         BX = new size of block in paragraphs
         Return: AX = 0001h success
            = 0000h failure
               BL = error code (80h,B0h,B2h) (see below)
               DX = maximum available size (RM386)
    34h  (QEMM 5.11 only, undocumented) ???
    44h  (QEMM 5.11 only, undocumented) ???
    80h  (Netroom RM386 v6.00) Reallocate upper memory block
         this function is identical to function 12h
    81h  (Netroom RM386 v6.00) re-enable HMA allocation
         Return: AX = 0001h (success)
    82h  (Netroom RM386 v6.00) Cloaking API
         DX = XMS handle of block containing protected-mode code
         CL = code size (00h 16-bit, else 32-bit)
         ESI, EDI = parameters to pass to protected-mode code
         Return: AX = status
             0001h success
             0000h failed
                 BL = error code (A2h,B0h) (see below)
         Note: this calls offset 0 in the XMS memory block with
        EBX = physical address of block's start
        CS = code selector for XMS block at EBX (16-bit or 32-bit)
        DS = data selector for XMS block, starting at EBX
        ES = selector for V86 memory access to full real-mode 1088K
        GS = selector for full flat address space
        ESI, EDI from V86 mode
    83h  (Netroom RM386 v6.00) Create new UMB entry
         BX = segment of high-memory block
         DX = first page of start of block
         CX = number of consecutive pages in block
         DI = start of UMB in block
         Return: AX = 0001h (success)
             DI = segment of first high-DOS block
         Note: the new UMB is not linked into the high-memory chain
    84h  (Netroom RM386 v6.00) Get all XMS handles info
         CX = size of buffer for handle info
         ES:DI -> buffer for handle info (see below)
         Return: AX = 0001h (success)
             DX = current number of allocated XMS handles
    88h  (XMS v3.0) Query free extended memory
         Return: EAX = largest block of extended memory, in KB
             BL = status
             00h success
             80h not implemented (i.e. on a 286 system)
             81h VDISK detected
             A0h all extended memory allocated
             ECX = physical address of highest byte of memory
                (valid even on error codes 81h and A0h)
             EDX = total Kbytes of extended memory (0 if status A0h)
    89h  (XMS v3.0) Allocate any extended memory
         EDX = Kbytes needed
         Return: AX = 0001h success
                DX = handle for allocated block (free with AH=0Ah)
            = 0000h failure
                BL = status (80h,81h,A0h,A1h,A2h) (see below)
    8Eh  (XMS v3.0) Get extended EMB handle information
         DX = handle
         Return: AX = 0001h success
                BH = block's lock count
                CX = number of free handles left
                EDX = block size in KB
            = 0000h failure
                BL = status (80h,81h,A2h) (see below)
         BUG: DOS 6.0 HIMEM.SYS leaves CX unchanged
    8Fh  (XMS v3.0) Reallocate any extended memory block
         DX = unlocked handle
         EBX = new size in KB
         Return: AX = 0001h success
            = 0000h failure
                BL = status (80h,81h,A0h-A2h,ABh) (see below)
Notes:    HIMEM.SYS requires at least 256 bytes free stack space
    the XMS driver need not implement functions 10h through 12h to be
      considered compliant with the standard
BUG:    HIMEM v3.03-3.07 crash on an 80286 machine if any of the 8Xh functions
      are called

Error codes returned in BL:
 00h    successful
 80h    function not implemented
 81h    Vdisk was detected
 82h    an A20 error occurred
 8Eh    a general driver error
 8Fh    unrecoverable driver error
 90h    HMA does not exist
 91h    HMA is already in use
 92h    DX is less than the /HMAMIN= parameter
 93h    HMA is not allocated
 94h    A20 line still enabled
 A0h    all extended memory is allocated
 A1h    all available extended memory handles are allocated
 A2h    invalid handle
 A3h    source handle is invalid
 A4h    source offset is invalid
 A5h    destination handle is invalid
 A6h    destination offset is invalid
 A7h    length is invalid
 A8h    move has an invalid overlap
 A9h    parity error occurred
 AAh    block is not locked
 ABh    block is locked
 ACh    block lock count overflowed
 ADh    lock failed
 B0h    only a smaller UMB is available
 B1h    no UMB's are available
 B2h    UMB segment number is invalid

Format of EMM structure:
Offset    Size    Description
 00h    DWORD    number of bytes to move (must be even)
 04h    WORD    source handle
 06h    DWORD    offset into source block
 0Ah    WORD    destination handle
 0Ch    DWORD    offset into destination block
Notes:    if source and destination overlap, only forward moves (source base
      less than destination base) are guaranteed to work properly
    if either handle is zero, the corresponding offset is interpreted
      as a real-mode address referring to memory directly addressable
      by the processor

Format of XMS handle info [array]:
Offset    Size    Description
 00h    BYTE    handle
 01h    BYTE    lock count
 02h    DWORD    handle size
 06h    DWORD    handle physical address (only valid if lock count nonzero)
--------m-2F4320-----------------------------
INT 2F U - HIMEM.SYS - Mach 20 SUPPORT
    AX = 4320h
    ???
Return: ???
--------m-2F4330-----------------------------
INT 2F UC - HIMEM.SYS v2.77+ - GET EXTERNAL A20 HANDLER ADDRESS
    AX = 4330h
Return: AL = 80h if external A20 handler provided
        ES:BX -> external A20 handler
        CL = ???
Note:    HIMEM.SYS calls this function to allow an external program to provide
      an A20 handler (i.e. to support a machine not supported by HIMEM
      itself)

External A20 handler called with:
    AX = function
        0000h disable A20
        0001h enable A20
    Return: AX = status
            0000h failure
            0001h successful
SeeAlso: AX=4308h,AX=4310h
--------E-2F43E0-----------------------------
INT 2F - Novell DOS Protected Mode Services (DPMS) - INSTALLATION CHECK
    AX = 43E0h
Return: AX = 0000h if installed
        ES:BX -> registration structure (see below)
Note:    this specification is still in beta
SeeAlso: INT 2F/AX=1687h

Format of registration structure:
Offset    Size    Description
 00h    DWORD    real-mode API entry point
 04h    DWORD    16-bit protected-mode API entry point
 08h  8 BYTEs    reserved (0)
 10h  8 BYTEs    blank-padded server OEM name
 18h    WORD    flags
        bit 0: fast processor reset available (286 only)
        bits 1-15 reserved (undefined)
 1Ah  2 BYTEs    DPMS version (major,minor)
 1Ch    BYTE    CPU type (02h = 286, 03h = 386 or higher)

Call DPMS entry point with:
    AX = 0100h call protected-mode procedure
        CX = number of words of stack to copy
        ES:DI -> callup/down register structure (see below)
        Return: CF clear if successful
            CF set on error
                AX = error code (see below)
    AX = 0101h call real-mode procedure (RETF return)
        CX = number of words of stack to copy
        ES:DI -> callup/down register structure (see below)
        Return: CF clear if successful
            CF set on error
                AX = error code (see below)
    AX = 0102h call real-mode procedure (IRET return)
        CX = number of words of stack to copy
        ES:DI -> callup/down register structure (see below)
        Return: CF clear if successful
            CF set on error
                AX = error code (see below)
    AX = 0103h call real-mode interrupt handler
        BL = interrupt number
        CX = number of words of stack to copy
        ES:DI -> callup/down register structure (see below)
        Return: CF clear if successful
            CF set on error
                AX = error code (see below)
    AX = 0200h allocate descriptors
        CX = number of descriptors to allocate
        Return: CF clear if successful
                AX = first descriptor allocated
            CF set on error
                AX = error code (see below)
    AX = 0201h free a descriptor
        BX = descriptor
        Return: CF clear if successful
            CF set on error
                AX = error code (see below)
    AX = 0202h create alias descriptor
        BX = descriptor
        Return: CF clear if successful
                AX = alias descriptor
            CF set on error
                AX = error code (see below)
    AX = 0203h build alias to real-mode segment
        BX = descriptor
        CX = real-mode segment
        Return: CF clear if successful
            CF set on error
                AX = error code (see below)
    AX = 0204h set descriptor base
        BX = descriptor
        CX:DX = base address
        Return: CF clear if successful
            CF set on error
                AX = error code (see below)
    AX = 0205h set descriptor limit
        BX = descriptor
        CX = limit
        Return: CF clear if successful
            CF set on error
                AX = error code (see below)
    AX = 0206h set descriptor type/attribute
        BX = descriptor
        CL = type
        CH = attribute
        Return: CF clear if successful
            CF set on error
                AX = error code (see below)
    AX = 0207h get descriptor base
        BX = descriptor
        Return: CF clear if successful
                CX:DX = base address
            CF set on error
                AX = error code (see below)
    AX = 0300h get size of largest free block of memory
        Return: CF clear if successful
                BX:CX = size
            CF set on error
                AX = error code (see below)
    AX = 0301h allocate block of extended memory
        BX:CX = size
        Return: CF clear if successful
                BX:CX = base address
                SI:DI = handle
            CF set on error
                AX = error code (see below)
    AX = 0302h free block of extended memory
        SI:DI = handle
        Return: CF clear if successful
            CF set on error
                AX = error code (see below)
    AX = 0303h map linear memory
        ES:[DI] = DDS
        Return: CF clear if successful
                BX:CX = base address
                SI:DI = handle
            CF set on error
                AX = error code (see below)
    AX = 0304h unmap linear memory
        SI:DI = handle
        Return: CF clear if successful
            CF set on error
                AX = error code (see below)
    AX = 0400h relocate segment to extended memory
        ES:SI = base address
        CX = limit
        BL = type
        BH = attribute
        DX = selector or 0000h
        Return: CF clear if successful
                AX = selector
                BX:CX = new base address
                SI:DI = handle
            CF set on error
                AX = error code (see below)

Values for error code:
 8000h    general error
 8001h    unsupported function
 8011h    descriptor unavailable
 8012h    linear memory unavailable
 8013h    physical memory unavailable
 8021h    invalid value
 8022h    invalid selector
 8023h    invalid handle

Format of callup/down register structure:
Offset    Size    Description
 00h    DWORD    EDI
 04h    DWORD    ESI
 08h    DWORD    EBP
 0Ch  4 BYTEs    reserved (0)
 10h    DWORD    EBX
 14h    DWORD    EDX
 18h    DWORD    ECX
 20h    DWORD    EAX
 24h    DWORD    EIP
 28h    WORD    CS
 2Ah  2 BYTEs    reserved (0)
 2Ch    DWORD    EFLAGS
 30h    DWORD    ESP
 34h    WORD    SS
 36h  2 BYTEs    reserved (0)
 38h    WORD    ES
 3Ah  2 BYTEs    reserved (0)
 3Ch    WORD    DS
 3Eh  2 BYTEs    reserved (0)
 40h    WORD    FS
 42h  2 BYTEs    reserved (0)
 44h    WORD    GS
 46h  2 BYTEs    reserved (0)
--------E-2F44-------------------------------
INT 2F U - DOS Extender support???
    AH = 44h
    AL = function (at least 0Bh, 15h, 17h)
    ???
Return: ???
Note:    called by Codeview for Windows
SeeAlso: AH=86h
--------G-2F4500-----------------------------
INT 2F U - Microsoft Profiler (PROF.COM/VPROD.386) - INSTALLATION CHECK
    AX = 4500h
Return: AL = 01h if PROF.COM installed
    AL = 02h if VPROD.386 installed
SeeAlso: AX=4501h,AX=4502h
--------G-2F4501-----------------------------
INT 2F U - Microsoft Profiler (PROF.COM/VPROD.386) - SETUP PROFILER
    AX = 4501h
    BX = CSIPS buffer size in KB (first parameter for ProfSetup)
    CX = output limit in KB (second parameter for ProfSetup)
Note:    this call is not supported by PROF.COM
SeeAlso: AX=4502h,AX=4503h
--------G-2F4502-----------------------------
INT 2F U - Microsoft Profiler (PROF.COM/VPROD.386) - SET SAMPLING RATE
    AX = 4502h
    BL = sampling rate for PROF.COM (0 < BL <= 13)
        (01h = 8192/s, 04h = 1024/s, 08h = 32/s, 0Dh = 1/s)
    CX = sampling rate for VPROD.386
Note:    for PROF.COM, this programs the CMOS clock by setting BL+2 as the
      low four bits of CMOS register 0Ah.  The interruption rate is
      1 SHL (15 - BL) per second.
SeeAlso: AX=4501h,AX=4503h
--------G-2F4503-----------------------------
INT 2F U - Microsoft Profiler (PROF.COM/VPROD.386) - START PROFILING
    AX = 4503h
Notes:    Profiling is also turned on by the key combinations
      LeftShift + RightShift + Alt
      LeftShift + RightShift + Ctrl
    for PROF.COM, this call programs the CMOS clock by reading register
      0Ch, and setting bit 6 of register 0Bh.  It then makes sure that IRQ8
      is unmasked
SeeAlso: AX=4504h
--------G-2F4504-----------------------------
INT 2F U - Microsoft Profiler (PROF.COM/VPROD.386) - STOP PROFILING
    AX = 4504h
Notes:    profiling is also turned off by the key combination
      LeftShift + RightShift
    for PROF.COM, this programs the CMOS clock by reading register 0Ch
      and clearing bit 6 of register 0Bh.  It then masks IRQ8.
SeeAlso: AX=4503h,AX=4505h,AX=4506h,AX=4507h
--------G-2F4505-----------------------------
INT 2F U - Microsoft Profiler (PROF.COM/VPROD.386) - CLEAR PROFILING DATA
    AX = 4505h
SeeAlso: AX=4503h,AX=4504h,AX=4506h
--------G-2F4506-----------------------------
INT 2F U - Microsoft Profiler (PROF.COM/VPROD.386) - "ProfFlush"
    AX = 4506h
SeeAlso: AX=4505h,AX=4507h
--------G-2F4507-----------------------------
INT 2F U - Microsoft Profiler (PROF.COM/VPROD.386) - "ProfFinish"
    AX = 4507h
Note:    this call is essentially a "ProfStop" (AX=4504h) followed by
      "ProfFlush" (AX=4506h)
SeeAlso: AX=4504h,AX=4505h,AX=4506h
--------G-2F4508-----------------------------
INT 2F U - Microsoft Profiler (PROF.COM/VPROD.386) - ALTERNATE SEGDEBUG IFACE
    AX = 4508h
    BX = ordinal (or 0000h)
    CX = segment
    DX = instance (or 0000h)
    SI = type (or 0000h)
    ES:DI -> ASCIZ module name
Notes:    this call is an alternate entry to the profiler's SEGDEBUG
      interface, but only to function 0, for notifying the profiler of
      each new segment loaded.  The SHOWHITS utility then examines the
      profiler's output files (CSIPS.DAT and SEGENTRY.DAT) in conjunction
      with symbol files to provide information in a useful form.
    this call does not have a corresponding Windows function
SeeAlso: AX=4500h
--------D-2F4601-----------------------------
INT 2F U - DOS 5+ kernel - ???
    AX = 4601h
Return: ???
Note:    copies the MCB following the caller's PSP memory block into DOS data
      segment
SeeAlso: AX=4602h
--------D-2F4602-----------------------------
INT 2F U - DOS 5+ kernel - ???
    AX = 4602h
Return: ???
Note:    copies previously copied MCB from DOS data segment into MCB following
      caller's PSP memory block
SeeAlso: AX=4601h
--------E-2F46-------------------------------
INT 2F U - Windows/286 DOS Extender
    AH = 46h
    AL = subfunction (03h,04h)
Return: ???
Note:    these two subfunctions are called by MS Windows 3.0
--------v-2F4653CX0002-----------------------
INT 2F - F-PROT v1.x only - F-LOCK.EXE
    AX = 4653h
    CX = 0002h
    BX = subfunction
        0000h  installation check
        Return: AX = FFFFh
        0001h  uninstall
        Return: AX,BX,ES destroyed
        0002h  disable (v1.08 and below only)
        0003h  enable (v1.08 and below only)
Note:    F-LOCK is part of the F-PROT virus/trojan protection package by Fridrik
      Skulason
SeeAlso: AX=4653h/CX=0003h,AX=CA00h,INT 21/AX=4BEEh
Index:    installation check;F-LOCK|uninstall;F-LOCK
--------v-2F4653CX0003-----------------------
INT 2F - F-PROT v1.x only - F-XCHK.EXE
    AX = 4653h
    CX = 0003h
    BX = subfunction
        0000h  installation check
        Return: AX = FFFFh
        0001h  uninstall
        Return: AX,BX,ES destroyed
Note:    F-XCHK is part of the F-PROT virus/trojan protection package by Fridrik
      Skulason
SeeAlso: AX=4653h/CX=0002h,AX=4653h/CX=0004h,AX=CA00h
Index:    installation check;F-XCHK|uninstall;F-XCHK
--------v-2F4653CX0004-----------------------
INT 2F - F-PROT v1.x only - F-POPUP.EXE
    AX = 4653h
    CX = 0004h
    BX = subfunction
        0000h  installation check
        Return: AX = FFFFh
        0001h  uninstall
        Return: AX,BX,ES destroyed
        0002h  disable (v1.08 and below only)
           display message (v1.14+)
            other registers: ???
        0003h  enable (v1.08 and below only)
           display message (v1.14+)
            other registers: ???
            Return: AX = key pressed by user
Note:    F-POPUP is part of the F-PROT virus/trojan protection package by
      Fridrik Skulason
SeeAlso: AX=4653h/CX=0003h,AX=4653h/CX=0005h,AX=CA00h
Index:    installation check;F-POPUP|uninstall;F-POPUP
--------v-2F4653CX0005-----------------------
INT 2F - F-PROT v1.x only - F-DLOCK.EXE
    AX = 4653h
    CX = 0005h
    BX = subfunction
        0000h installation check
        Return: AX = FFFFh
        0001h uninstall
        Return: AX,BX,ES destroyed
Note:    F-DLOCK is part of the F-PROT virus/trojan protection package by
      Fridrik Skulason
SeeAlso: AX=4653h/CX=0004h,AX=CA00h
Index:    installation check;F-DLOCK|uninstall;F-DLOCK
--------W-2F4680-----------------------------
INT 2F U - MS Windows v3.0 - INSTALLATION CHECK
    AX = 4680h
Return: AX = 0000h MS Windows 3.0 running in real (/R) or standard (/S) mode,
           or DOS 5 DOSSHELL active
       nonzero  no Windows, Windows prior to 3.0, or Windows3 in enhanced
            mode
Note:    Windows 3.1 finally provides an installation check which works in all
      modes (see AX=160Ah)
SeeAlso: AX=1600h,AX=160Ah
----------2F47-------------------------------
INT 2F U - ???
    AH = 47h
    ???
Return: ???
Note:    reportedly called by Microsoft BASIC Compiler v7.0
--------K-2F4800-----------------------------
INT 2F - DOS 5+ DOSKEY - INSTALLATION CHECK
    AX = 4800h
Return: AL = nonzero if installed (DOS 5.0 and 6.0 return AX=AA02h)
        ES = segment of DOSKEY resident portion
Note:    DOSKEY chains if AL is not 00h or 10h on entry
SeeAlso: AX=4800h"PCED",AX=4810h
--------K-2F4800-----------------------------
INT 2F - PCED v2.1 - INSTALLATION CHECK
    AX = 4800h
Return: AX = AACDh if installed
        ES = segment of PCED kernel (PCED has multiple code segments)
Program: PCED v2.1 is a command line editor/history/macro facility by
      Cove Software.  It is the commercial version of the freeware CED.
Notes:    DOSKEY also responds to this call if installed, returning AX=AA02h.
    unlike DOSKEY, PCED does *not* chain if AL contains an
      unsupported function code.  It IRETs with all registers intact.
--------K-2F4810-----------------------------
INT 2F - DOS 5+ DOSKEY, PCED v2.1 - READ INPUT LINE FROM CONSOLE
    AX = 4810h
    DS:DX -> line buffer (see INT 21/AH=0Ah)
Return: AX = 0000h if successful
Notes:    the first byte (length) of the buffer MUST be 80h, or DOSKEY chains to
      the previous handler; PCED allows sizes other than 80h
    if the user's input is a macro name, no text is placed in the buffer
      even though AX=0000h on return; the program must immediately issue
      this call again to retrieve the expansion of the macro.  Similarly,
      if the user enters a special parameter such as $*, this call must
      be repeated to retrieve the expansion; on the second call, DOSKEY
      overwrites the macro name on the screen with its expansion.
    unlike DOSKEY, PCED expands all macros on the first call, so it is
      not necessary to make two calls; since the buffer is not empty on
      return, DOSKEY-aware programs will not make the second call
    DOSKEY chains if AL is not 00h or 10h on entry
SeeAlso: AX=4800h,INT 21/AH=0Ah
--------K-2F48C0-----------------------------
INT 2F - PCED v2.1 - PCED API
    AX = 48C0h
    DX = API function code
    other registers as required by the specified function
Return: CF clear if successful
    CF set on error
        AX = PCED error code
    other registers as appropriate for API function
Program: PCED v2.1 is a command line editor/history/macro facility by
      Cove Software.  It is the commercial version of the freeware CED.
Note:    the full API information is available from Cove Software
SeeAlso: AX=4800h"PCED",AX=48C1h,AX=48C2h,AX=48C3h
----------2F48C1BL00-------------------------
INT 2F - PCED/VSTACK - INSTALLATION CHECK
    AX = 48C1h
    BL = 00h
Return: AX = 0000h if installed
        BX = VSTACK resident segment
Program: VSTACK is a resident backscroll utility included as part of the PCED
      package
Note:    chains if BL <> 00h on entry
SeeAlso: AX=48C0h,AX=48C2h
----------2F48C2BL00-------------------------
INT 2F - PCED/ATTRIB - INSTALLATION CHECK
    AX = 48C2h
    BL = 00h
Return: AX = 0000h if installed
        BX = ATTRIB resident segment
Program: ATTRIB is a resident file attribute changer included as part of the
      PCED package
Note:    chains if BL <> 00h on entry
SeeAlso: AX=48C0h,AX=48C1h,AX=48C3h
--------K-2F48C3BL00-------------------------
INT 2F - PCED/KEYDEF - INSTALLATION CHECK
    AX = 48C3h
    BL = 00h
Return: AX = 0000h if installed
        BX = KEYDEF resident segment
Program: KEYDEF is a resident keyboard redefinition utility included as part
      of the PCED package
Note:    chains if BL <> 00h on entry
SeeAlso: AX=48C0h,AX=48C2h,AX=48C4h
----------2F48C4BL00-------------------------
INT 2F - PCED/FLIST - INSTALLATION CHECK
    AX = 48C4h
    BL = 00h
Return: AX = 0000h if installed
        BX = FLIST resident segment
Program: FLIST is a resident filelist processor included as part of the PCED
      package
Note:    chains if BL <> 00h on entry
SeeAlso: AX=48C0h,AX=48C3h,AX=48C5h
----------2F48C4BL00-------------------------
INT 2F - PCED/ASSOC - INSTALLATION CHECK
    AX = 48C4h
    BL = 00h
Return: AX = 0000h if installed
        BX = ASSOC resident segment
Program: ASSOC is a resident utility included as part of the PCED package which
      associated files with executable programs based on their extensions
Note:    chains if BL > 02h on entry
SeeAlso: AX=48C0h,AX=48C4h,AX=48C5h/BL=01h,AX=48C5h/BL=02h
----------2F48C5BL01-------------------------
INT 2F - PCED/ASSOC - VERSION CHECK
    AX = 48C5h
    BL = 01h
Return: AX = 0000h if installed
        BX = binary ASSOC version (BL = major, BH = minor)
Note:    chains if BL > 02h on entry
SeeAlso: AX=48C0h,AX=48C5h/BL=00h,AX=48C5h/BL=02h
----------2F48C5BL02-------------------------
INT 2F - PCED/ASSOC - ASSOCIATION TEST
    AX = 48C5h
    BL = 02h
    DS:SI -> ASCIZ filename
Return: AX = status
        0000h if filename is unknown
        0001h if there is an association defined for the file
    BX destroyed
Program: ASSOC is a resident utility included as part of the PCED package which
      associated files with executable programs based on their extensions
Note:    chains if BL > 02h on entry
SeeAlso: AX=48C0h,AX=48C5h/BL=00h,AX=48C5h/BL=01h
----------2F49-------------------------------
INT 2F U - ???
    AH = 49h
    ???
Return: ???
Note:    reportedly called by DOS 5.0 installation
--------D-2F4A00CX0000-----------------------
INT 2F CU - DOS 5+ - FLOPPY-DISK LOGICAL DRIVE CHANGE NOTIFICATION
    AX = 4A00h
    CX = 0000h
    DH = new drive number
    DL = current drive number
Return: CX = FFFFh to skip "Insert diskette for drive X:" message
Note:    called by MS-DOS 5.0+ IO.SYS just before displaying the message
      "Insert diskette for drive X:" on single-floppy systems
--------D-2F4A01-----------------------------
INT 2F - DOS 5+ - QUERY FREE HMA SPACE
    AX = 4A01h
Return: BX = number of bytes available in HMA (0000h if DOS not using HMA)
    ES:DI -> start of available HMA area (FFFFh:FFFFh if not using HMA)
Note:    called by Windows 3.1 DOSX.EXE
SeeAlso: AX=4310h,AX=4A02h
--------D-2F4A02-----------------------------
INT 2F - DOS 5+ - ALLOCATE HMA SPACE
    AX = 4A02h
    BX = number of bytes
Return: ES:DI -> start of allocated HMA block or FFFFh:FFFFh
    BX = number of bytes actually allocated (rounded up to next paragraph
        for DOS 5.0 and 6.0)
Notes:    this call is not valid unless DOS is loaded in the HMA (DOS=HIGH)
    called by Windows 3.1 DOSX.EXE
SeeAlso: AX=4A01h
--------T-2F4A05-----------------------------
INT 2F U - DOS 5+ DOSSHELL - TASK SWITCHING API???
    AX = 4A05h
    SI = function
        0000h reset???
        0001h ???
        ES:BP -> 80-byte buffer containing ???
        0002h ???
        0003h ???
        0004h ???
        BL = ???
        0005h ???
        0006h get ???
        Return: ES:SI -> ???
        0007h get ???
        Return: AX = ???
        0008h get ???
        Return: DX:AX -> ??? (internal control data of some kind)
        0009h get ???
        Return: ES:SI -> ??? (apparently identical to function 0006h)
        000Ah ???
        BL = length of buffer
        ES:BP -> buffer containing ???
        000Bh get ???
        Return: AX = ???
        000Ch ???
        BL = ???
        Return: if BL nonzero on entry
                DX:AX -> ???
            if BL = 00h on entry
                ES:SI -> ???
Notes:    DOSSHELL chains to the previous handler if SI is not one of the values
      listed above
    the DOSSWAP.EXE module calls functions 03h,04h,05h,07h,08h,09h,0Ch
    the Windows 3.1 DSWAP.EXE and WSWAP.EXE task switchers use these calls
SeeAlso: AX=4B01h
--------D-2F4A06-----------------------------
INT 2F CU - DOS 5+ - DOS SUPERVISOR "REBOOT PANEL" - ADJUST MEMORY SIZE
    AX = 4A06h
    DX = segment following last byte of conventional memory
Return: DX = segment following last byte of memory available for use by DOS
Desc:    used to override the default memory size when booting diskless
      workstations
Notes:    called by MS-DOS 5+ IO.SYS startup code if the signature "RPL" is
      present three bytes beyond the INT 2F handler; this call overrides
      the value returned by INT 12
    hooked by RPL code at the top of memory to protect itself from being
      overwritten; DOS builds a memory block with owner = 0008h and name
      "RPL" which must be freed by the RPL code when it is done
SeeAlso: INT 12
--------N-2F4A07-----------------------------
INT 2F U - RESERVED FOR PROTMAN SUPPORT
    AX = 4A07h
    ???
Return: ???
--------c-2F4A10BX0000-----------------------
INT 2F - SMARTDRV v4.00+ - INSTALLATION CHECK AND HIT RATIOS
    AX = 4A10h
    BX = 0000h
    CX = EBABh (v4.1+; see Note)
Return: AX = BABEh if installed
        DX:BX = cache hits
        DI:SI = cache misses
        CX = ???
        BP = version in BCD (4.10 = 0410h)
Notes:    most of the SMARTDRV API, including this call, is supported by
      PC-Cache v8.0
    if DBLSPACE.BIN is installed but SMARTDRV has not yet been installed,
      unless CX=EBABh on entry, DBLSPACE.BIN displays the error message
      "Cannot run SMARTDrive 4.0 with DoubleSpace" and aborts the caller
      with INT 21/AX=4C00h
    SMARTDRV v3.x had a completely different API using IOCTL calls
SeeAlso: AX=4A10h/BX=0001h,AX=4A10h/BX=0004h,AX=4A10h/BX=0005h
SeeAlso: AX=4A10h/BX=0007h,AX=4A10h/BX=1234h,AX=4A11h/BX=0000h
SeeAlso: INT 21/AX=4402h"SMARTDRV",INT 21/AX=4403h"SMARTDRV"
--------c-2F4A10BX0001-----------------------
INT 2F - SMARTDRV v4.00+ - FLUSH BUFFERS
    AX = 4A10h
    BX = 0001h
Note:    this function is also supported by PC-Cache v8.0.
SeeAlso: AX=4A10h/BX=0000h,AX=4A10h/BX=0002h
--------c-2F4A10BX0002-----------------------
INT 2F - SMARTDRV v4.00+ - RESET CACHE
    AX = 4A10h
    BX = 0002h
Note:    this function is also supported by PC-Cache v8.0.
SeeAlso: AX=4A10h/BX=0000h,AX=4A10h/BX=0001h
--------c-2F4A10BX0003-----------------------
INT 2F - SMARTDRV v4.00+ - STATUS
    AX = 4A10h
    BX = 0003h
    BP = drive # (0=A, 1=B, etc.)
    DL = subfunction
        00h only get information
        01h turn on read cache
        02h turn off read cache
        03h turn on write cache
        04h turn off write cache
Return: AX = BABEh if OK
    DL = status
        bit 7  not cached
        bit 6  write-through (not write-cached)
        bit 5  ???
        bits 0-4 drive # (0=A, 1=B...)
    DL = FFh if drive does not exist
Notes:    If the read cache is off, reads will not be cached, but writes will
      continue to be cached if the write-cache is enabled.
    this function is also supported by PC-Cache v8.0.
SeeAlso: AX=4A10h/BX=0000h
--------c-2F4A10BX0004-----------------------
INT 2F - SMARTDRV v4.00+ - GET CACHE SIZE
    AX = 4A10h
    BX = 0004h
Return: AX = current size in elements???
    BX = largest number of elements
    CX = size of elements in bytes
    DX = number of elements under Windows
Note:    this function is also supported by PC-Cache v8.0.
SeeAlso: AX=4A10h/BX=0000h,AX=4A10h/BX=0003h,AX=4A10h/BX=0005h
--------c-2F4A10BX0005-----------------------
INT 2F - SMARTDRV v4.00+ - GET DOUBLE-BUFFER STATUS
    AX = 4A10h
    BX = 0005h
    BP = drive # (0=A, 1=B...)
Return: AX = BABEh if double-buffered
        ES:DI -> ???
SeeAlso: AX=4A10h/BX=0000h,AX=4A10h/BX=0003h,AX=4A10h/BX=0006h
--------c-2F4A10BX0006-----------------------
INT 2F CU - SMARTDRV v4.00+ - CHECK IF DRIVE CACHEABLE
    AX = 4A10h
    BX = 0006h
    CL = drive number (01h = A:)
Return: AX = 0006h if drive should not be cached by SMARTDRV
Note:    called by SMARTDRV at startup to determine whether it should cache
      a particular drive
SeeAlso: AX=4A10h/BX=0000h
--------c-2F4A10BX0007-----------------------
INT 2F - SMARTDRV v4.00+ - GET DEVICE DRIVER FOR DRIVE
    AX = 4A10h
    BX = 0007h
    BP = drive number (00h=A:)
Return: DL = ???
    ES:DI -> device driver header for drive
Note:    this function is also supported by PC-Cache v8.0.
    this call is reported to always return the driver header of the
      standard block driver (A:-C:+) for SmartDrive v5.00 from MS-DOS 6.2
SeeAlso: AX=4A10h/BX=0000h,AX=4A11h/BX=0003h,AX=4A11h/BX=0004h
--------c-2F4A10BX0008-----------------------
INT 2F - SMARTDRV v4.20+ - GET/SET FLUSH BEFORE PROMPT, CD-ROM SUPPORT
    AX = 4A10h
    BX = 0008h
    DL = subfunction
        00h set
        DH = new states
            bit 0: flush before prompt
            bits 1-7 reserved
        01h get
        Return: DH = status flags
                bit 0: (v4.2+) flush before prompt
                bit 1: (v5.0+) CD-ROM caching support installed
Note:    v4.2 was an interim release to fix problems in the SMARTDRV included
      with MS-DOS 6.00; v5.00 is included with MS-DOS 6.2
--------c-2F4A10BX000A-----------------------
INT 2F - SMARTDRV v4.00+ - GET TABLE POINTER???
    AX = 4A10h
    BX = 000Ah
Return: ES:BX -> table of about 10 bytes or 5 words. Seems to be words
         pointing to memory addresses containing info??? (see below)
Note:    this function is also supported by PC-Cache v8.0.
SeeAlso: AX=4A10h/BX=0000h

Format of data table:
Offset    Size    Description
 00h  8 BYTEs    ???
 08h    WORD    offset of WORD containing number of elements in cache
--------c-2F4A10BX1234-----------------------
INT 2F - SMARTDRV v4.00+ - SIGNAL SERIOUS ERROR
    AX = 4A10h
    BX = 1234h
Desc:    pops up a message box saying that a serious error occurred and to hit
      R to retry.
Note:    this function is also supported by PC-Cache v8.0.
SeeAlso: AX=4A10h/BX=0000h
--------d-2F4A11BX0000-----------------------
INT 2F - DBLSPACE.BIN - "GetVersion" - INSTALLATION CHECK
    AX = 4A11h
    BX = 0000h
Return: AX = 0000h (successful)
    BX = 444Dh ("DM")
    CL = first drive letter used by DBLSPACE (41h ['A'] = A:)
    CH = number of drive letters used by DBLSPACE
    DX = internal DBLSPACE.BIN version number (bits 14-0)
        bit 15 set if DBLSPACE.BIN has not yet been relocated to final
        position in memory (i.e. DBLSPACE.SYS /MOVE)
Program: DBLSPACE.BIN is the resident driver for DoubleSpace, the
      disk-compression software bundled with MS-DOS 6.0
SeeAlso: AX=4A11h/BX=0001h,AX=4A11h/BX=0002h,AX=4A11h/BX=0003h
SeeAlso: AX=4A11h/BX=0005h,AX=4A11h/BX=0007h,AX=4A11h/BX=FFFFh
SeeAlso: INT 21/AX=4404h"DBLSPACE"
--------d-2F4A11BX0001-----------------------
INT 2F - DBLSPACE.BIN - "GetDriveMapping" - GET DRIVE MAPPING
    AX = 4A11h
    BX = 0001h
    DL = drive number (0=A:)
Return: AX = status (see also below)
        0000h successful
        if DL was compressed drive,
            BL = host drive (bit 7 set if drive is compressed)
        else if DL was host drive,
            BL = compressed drive
        else
            BL = specified drive (if available for DoubleSpace)
        BH = DoubleSpace sequence number
        other error code (0101h) (see below)
        apparently never returned for the MS-DOS 6.2 DoubleSpace
Note:    the compressed volume file for the specified compressed drive is
      host:\DBLSPACE.sequence
SeeAlso: AX=4A11h/BX=0000h

Values for status:
 0000h    successful
 0100h    bad function
 0101h    invalid drive
 0102h    not a compressed drive
 0103h    drive already swapped
 0104h    drive not swapped
--------d-2F4A11BX0002-----------------------
INT 2F - DBLSPACE.BIN - "Swap Drive" - SWAP DRIVE LETTERS OF CVF AND HOST DRIVE
    AX = 4A11h
    BX = 0002h
    DL = drive number (0=A:) of compressed drive to swap with its host
Return: AX = status (0000h,0101h,0102h,0103h) (see AX=4A11h/BX=0001h)
Note:    this function is intended for use by DBLSPACE.EXE only
SeeAlso: AX=4A11h/BX=0000h
--------d-2F4A11BX0003-----------------------
INT 2F - DBLSPACE.BIN - "DSGetEntryPoints" - GET DEVICE DRIVER ENTRY POINTS
    AX = 4A11h
    BX = 0003h
    CL = drive number (0=A:) of compressed drive
Return: CL = FFh on error (not compressed drive)
       = other driver unit number of host drive
        ES:SI -> device driver's strategy routine
        ES:DI -> device driver's interrupt routine
    BX destroyed
Note:    in conjunction with subfunction 0004h, this call allows disk caches
      like SMARTDRV to apply a device driver wrapper to DoubleSpaced
      drives just like SMARTDRV applies to regular block devices
SeeAlso: AX=4A10h/BX=0007h,AX=4A11h/BX=0000h,AX=4A11h/BX=0004h
--------d-2F4A11BX0004-----------------------
INT 2F - DBLSPACE.BIN - "DSSetEntryPoints" - SET DEVICE DRIVER ENTRY POINTS
    AX = 4A11h
    BX = 0004h
    CL = drive number (0=A:) of compressed drive
    DL = unit number for new driver entry points
    DH = 00h
    ES:SI -> device driver strategy routine to call for drive
    ES:DI -> device driver interrupt routine to call for drive
Return: CL = FFh on error (not a compressed drive)
    BX destroyed
Program: DBLSPACE.BIN is the resident driver for DoubleSpace, the
      disk-compression software bundled with MS-DOS 6.0
Note:    in conjunction with subfunction 0003h, this call allows disk caches
      like SMARTDRV to apply a device driver wrapper to DoubleSpaced
      drives just like SMARTDRV applies to regular block devices
SeeAlso: AX=4A10h/BX=0007h,AX=4A11h/BX=0000h,AX=4A11h/BX=0003h
--------d-2F4A11BX0005-----------------------
INT 2F - DBLSPACE.BIN - "ActivateDrive" - MOUNT COMPRESSED DRIVE
    AX = 4A11h
    BX = 0005h
    DL = drive number (0=A:) to assign to new drive
    ES:SI -> activation record (see below)
Return: status returned in activation record (see below)
SeeAlso: AX=4A11h/BX=0000h,AX=4A11h/BX=0006h

Format of activation record:
Offset    Size    Description
 00h  2 BYTEs    signature "MD" (4Dh 44h)
 02h    BYTE    4Dh ('M') mount command
 03h    BYTE    error code (set to FFh before calling)
        00h successful
        01h drive letter not available for DoubleSpace
        02h drive letter already in use
        03h no more disk units (increase MaxRemovableDrives in .INI)
        09h CVF too fragmented
 04h    BYTE    host drive number (0=A:)
 05h    ???    DISK_UNIT structure (not documented)
--------d-2F4A11BX0006-----------------------
INT 2F - DBLSPACE.BIN - "DeactivateDrive" - UNMOUNT COMPRESSED DRIVE
    AX = 4A11h
    BX = 0006h
    DL = drive number (0=A:) to unmount
Return: AX = status (0000h,0102h) (see AX=4A11h/BX=0001h)
SeeAlso: AX=4A11h/BX=0000h,AX=4A11h/BX=0005h
--------d-2F4A11BX0007-----------------------
INT 2F - DBLSPACE.BIN - "GetDriveSpace" - GET SPACE AVAIL ON COMPRESSED DRIVE
    AX = 4A11h
    BX = 0007h
    DL = compressed drive number (0=A:)
Return: AX = status (0000h,0102h) (see also AX=4A11h/BX=0001h)
        0000h successful
        DS:SI -> free space record (see below)
Program: DBLSPACE.BIN is the resident driver for DoubleSpace, the
      disk-compression software bundled with MS-DOS 6.0
SeeAlso: AX=4A11h/BX=0000h,AX=4A11h/BX=0008h

Format of free space record:
Offset    Size    Description
 00h    DWORD    total number of sectors in drive's sector heap
 04h    DWORD    number of free sectors in drive's sector heap
--------d-2F4A11BX0008-----------------------
INT 2F - DBLSPACE.BIN - "GetFileFragmentSpace" - GET SIZE OF FRAGMENT HEAP
    AX = 4A11h
    BX = 0008h
    DL = compressed drive number (0=A:)
Return: AX = status (0000h,0102h) (see also AX=4A11h/BX=0001h)
        0000h successful
        BX = maximum entries in File Fragment heap
        CX = available entries in File Fragment heap
SeeAlso: AX=4A11h/BX=0000h,AX=4A11h/BX=0007h,AX=4A11h/BX=0009h
--------d-2F4A11BX0009-----------------------
INT 2F - DBLSPACE.BIN - "GetExtraInfo" - DETERMINE NUMBER OF DISK_UNIT STRUCTS
    AX = 4A11h
    BX = 0009h
    DL = compressed drive number (0=A:)
Return: AX = status (see also AX=4A11h/BX=0001h)
        0000h successful
        CL = number of DISK_UNIT structures allocated
            (see AX=4A11h/BX=0005h)
        CH = DoubleGuard enabled-checks bitflags in bits 6-0 (DOS 6.2)
Note:    the DoubleGuard checks are enabled or disabled as a block by the
      DoubleGuard= line in DBLSPACE.INI; they may be individually set with
      the CheckSum= line.
SeeAlso: AX=4A11h/BX=0000h,AX=4A11h/BX=0008h
--------d-2F4A11BX000A-----------------------
INT 2F - DBLSPACE.BIN 6.2 - SET AUTOMOUNT DRIVES
    AX = 4A11h
    BX = 000Ah
    CX:DX = bitmask of drives on which to enable AutoMount
        (DX bit 0 = A:, CX bit 0 = P:, etc.)
Return: AX = 0000h if supported
        CX:DX = old mask or 0000h:0000h on error
    BX destroyed
SeeAlso: AX=4A11h/BX=000Bh
--------d-2F4A11BX000B-----------------------
INT 2F - DBLSPACE.BIN 6.2 - GET AUTOMOUNT DRIVES
    AX = 4A11h
    BX = 000Bh
Return: AX = 0000h if supported
        CX:DX = mask of drives with AutoMount enabled
        0000h:0000h on error
    BX destroyed
SeeAlso: AX=4A11h/BX=000Ah
--------d-2F4A11BXFFFE-----------------------
INT 2F U - DBLSPACE.BIN - RELOCATE
    AX = 4A11h
    BX = FFFEh
    ES = segment to which to relocate DBLSPACE.BIN
Return: ???
Notes:    called by DBLSPACE.SYS to relocate DBLSPACE.BIN to its final position
      in memory
    this function also unhooks and discards the code providing this
      function and AX=4A11h/BX=FFFFh
SeeAlso: AX=4A11h/BX=FFFFh
--------d-2F4A11BXFFFF-----------------------
INT 2F U - DBLSPACE.BIN - GET RELOCATION SIZE
    AX = 4A11h
    BX = FFFFh
Return: AX = number of paragraphs needed by DBLSPACE.BIN
Note:    used by DBLSPACE.SYS to relocate the DBLSPACE driver to its final
      position in memory
SeeAlso: AX=4A11h/BX=0000h,AX=4A11h/BX=FFFEh
--------d-2F4A12CX4D52-----------------------
INT 2F - Microsoft Realtime Compression Interface (MRCI) - RAM-BASED SERVER
    AX = 4A12h
    CX = 4D52h ("MR")
    DX = 4349h ("CI")
Return: CX = 4943h ("IC") if installed
    DX = 524Dh ("RM") if installed
        ES:DI -> MRCINFO structure (see INT 1A/AX=B001h)
Note:    this call is functionally identical to INT 1A/AX=B001h, but should be
      called first, as the latter call is used for the first, ROM-based
      MRCI server, while this call is used for RAM-based servers which
      may be partially or entirely replacing a prior server
SeeAlso: INT 1A/AX=B001h
--------d-2F4A13-----------------------------
INT 2F U - DBLSPACE.BIN - GET ??? ENTRY POINTS
    AX = 4A13h
Return: AX = 134Ah if supported
        ES:BX -> entry point record (see below)
SeeAlso: AX=4A11h/BX=0000h

Format of entry point record:
Offset    Size    Description
 00h    DWORD    pointer to FAR function for ???
 04h  5 BYTEs    FAR JUMP instruction to ???
--------N-2F4B-------------------------------
INT 2F - LAN Manager 2.0 DOS Enh NETWKSTA.EXE - NETWORK WORKSTATION REDIRECTOR
    AH = 4Bh
    ???
Return: ???
Note:    LAN Manager enhanced mode adds features beyond the standard redirector
      file/printer services
SeeAlso: AX=118Ah,AX=4100h,AH=42h
--------T-2F4B01-----------------------------
INT 2F C - DOS 5+ TASK SWITCHER - BUILD CALLOUT CHAIN
    AX = 4B01h
    CX:DX -> task switcher entry point (see AX=4B02h)
    ES:BX = 0000h:0000h
Return: ES:BX -> callback info structure (see below) or 0000h:0000h
Notes:    called by the task switcher
    this function is hooked by clients which require notification of task
      switcher activities; the call must first be passed on to the prior
      handler with registers unchanged using a simulated interrupt.     On
      return, the client must build a callback info structure and store
      the returned ES:BX in the "next" field, then return the address of
      its own callback info structure.
    a client program must add itself to the notification chain if it
      provides services to other programs; before terminating, it must
      remove itself from the chain by calling the task switcher's entry
      point with AX=0005h (see AX=4B02h)
    the task switcher entry point should not be saved, as it is subject to
      change and will be provided on any notification call
    the Windows 3.1 Standard Mode supports this API
SeeAlso: AX=160Bh,AX=4B02h

Format of callback info structure:
Offset    Size    Description
 00h    DWORD    pointer to next callback info structure
 04h    DWORD    pointer to notification function (see below)
 08h    DWORD    reserved
 0Ch    DWORD    address of zero-terminated list of API info structures
        (see AX=4B02h)

Notification function is called with:
    AX = function
        0000h switcher initialization
        Return: AX = 0000h if OK to load
               = nonzero to abort task switcher
        0001h query suspend
        BX = session ID
        Return: AX = 0000h if OK to switch session
               = 0001h if not
        0002h suspend session
        BX = session ID
        interrupts disabled
        Return: AX = 0000h if OK to switch session
               = 0001h if not
        0003h activate session
        BX = session ID
        CX = session status flags
            bit 0: set if first activation of session
            bits 1-15: reserved (0)
        interrupts disabled
        Return: AX = 0000h
        0004h session active
        BX = session ID
        CX = session status flags
            bit 0: set if first activation of session
            bits 1-15: reserved (0)
        Return: AX = 0000h
        0005h create session
        BX = session ID
        Return: AX = 0000h if OK to create session
               = 0001h if not
        0006h destroy session
        BX = session ID
        Return: AX = 0000h
        0007h switcher termination
        BX = flags
            bit 0: set if calling switcher is only switcher loaded
            bits 1-15: reserved (0)
        Return: AX = 0000h
    ES:DI -> task switcher entry point (see AX=4B02h)
Notes:    function 0000h is generally called by the program which controls or
      invokes the task switcher, rather than by the task switcher itself;
      the entry point supplied to this function is not necessarily the
      entry point to the task switcher itself, and may be 0000h:0000h.  If
      any client indicates that loading is not possible, all clients will
      be called with function 0007h; thus it is possible for a client to
      receive a termination notice without a corresponding initialization
      notice.
    except for functions 0002h and 0003h, the notification handler is
      called with interrupts enabled and may make any INT 21h function
      call; interrupts must not be enabled in functions 0002h and 0003h
    function 0007h may be called with ES:DI = 0000h:0000h if the entry
      point is no longer valid
--------T-2F4B02BX0000-----------------------
INT 2F - DOS 5+ TASK SWITCHER - INSTALLATION CHECK
    AX = 4B02h
    BX = 0000h
    ES:DI = 0000h:0000h
Return: ES:DI = 0000h:0000h if task switcher not loaded
    ES:DI -> task switcher entry point (see below) if loaded
        AX = 0000h
Notes:    the returned entry point is that for the most-recently loaded task
      switcher; the entry points for prior task switchers may be determined
      with the "get version" call (see below)
    this function is supported by PC Tools v8+ CPTASK
SeeAlso: AX=4A05h,AX=4B03h

Call task switcher entry point with:
    AX = 0000h get version
        Return: CF clear if successful
                AX = 0000h
                ES:BX -> task switcher version struct (see below)
            CF set if unsupported function
    AX = 0001h test memory region
        ES:DI -> first byte to be tested
        CX = size of region to test
        Return: CF clear if successful
                AX = memory type of tested region
                0000h global
                0001h global and local
                0002h local (replaced on session switch)
            CF set if unsupported function
    AX = 0002h suspend switcher
        ES:DI -> new task switcher's entry point
        Return: CF clear if successful
                AX = state
                0000h switcher has been suspended
                0001h switcher not suspended, new switcher must
                    abort
                0002h switcher not suspended, but new switcher
                    may run anyway
            CF set if unsupported function
    AX = 0003h resume switcher
        ES:DI -> new task switcher's entry point
        Return: CF clear if successful
                AX = 0000h
            CF set if unsupported function
    AX = 0004h hook notification chain
        ES:DI -> callback info structure to be added to chain
            (see AX=4B01h)
        Return: CF clear if successful
                AX = 0000h
            CF set if unsupported function
    AX = 0005h unhook notification chain
        ES:DI -> callback info structure to be removed from chain
            (see AX=4B01h)
        Return: CF clear if successful
                AX = 0000h
            CF set if unsupported function
    AX = 0006h query API support
        BX = asynchronous API identifier
        Return: CF clear if successful
                AX = 0000h
                ES:BX -> API info structure (see below) for the
                    client which provides the highest
                    level of
            CF set if unsupported function

Format of task switcher version structure:
Offset    Size    Description
 00h    WORD    major version of supported protocol  (current protocol is 1.0)
 02h    WORD    minor version of supported protocol
 04h    WORD    major version of task switcher
 06h    WORD    minor version of task switcher
 08h    WORD    task switcher ID (see AX=4B03h)
 0Ah    WORD    operation flags
        bit 0: set if task switcher disabled
        bits 1-15: reserved (0)
 0Ch    DWORD    pointer to ASCIZ task switcher name
        ("MS-DOS Shell Task Switcher" for DOSSHELL task switcher)
 10h    DWORD    pointer to previous task switcher's entry point or 0000h:0000h

Format of API info structure:
Offset    Size    Description
 00h    WORD    size of structure in bytes (000Ah)
 02h    WORD    API identifier
        0001h NetBIOS
        0002h 802.2
        0003h TCP/IP
        0004h LAN Manager named pipes
        0005h Novell NetWare IPX
 04h    WORD    major version \ of highest version of API for which the support
 06h    WORD    minor version / level specified in the next field is provided
 08h    WORD    support level
        0001h minimal support
        0002h API-level support
        0003h switcher compatibility
        0004h seamless compatibility
--------T-2F4B03-----------------------------
INT 2F - DOS 5+ TASK SWITCHER - ALLOCATE SWITCHER ID
    AX = 4B03h
    ES:DI -> task switcher entry point (see AX=4B02h)
Return: AX = 0000h
    BX = switcher ID (0001h-000Fh), or 0000h if no more available
Notes:    if a task switcher has determined that it is the first to be loaded, it
      must allocate an identifier for itself and provide this function to
      all subsequent task switchers; if it is not the first to be loaded,
      it must call this function to allocate an ID.     The switcher ID is
      used as the high four bits of all session identifiers to ensure
      unique session IDs.
    if no more switcher IDs are available, the new task switcher making the
      call must terminate or disable itself
    the task switcher providing the identifiers may call the new task
      switcher's entry point as needed
    this call is available from within DOSSHELL even if the task switcher
      is not installed
    this function is supported by PC Tools v8+ CPTASK, but appears to
      always return an ID of 0000h
SeeAlso: AX=4B02h,AX=4B04h
--------T-2F4B04-----------------------------
INT 2F - DOS 5+ TASK SWITCHER - FREE SWITCHER ID
    AX = 4B04h
    BX = switcher ID
    ES:DI -> task switcher entry point (see AX=4B02h)
Return: AX = 0000h
    BX = status
        0000h successful
        other error (invalid ID or ID not allocated)
Notes:    called by a task switcher when it exits, unless it was the first loaded
      and is providing the support for AX=4B03h and AX=4B04h
    the task switcher providing the identifiers may call the terminating
      task switcher's entry point as needed
    this call is available from within DOSSHELL even if the task switcher
      is not installed
    this call is supported by PC Tools v8+ CPTASK, but appears to return
      sucessfully no matter which ID is given
SeeAlso: AX=4B02h,AX=4B03h
--------T-2F4B05-----------------------------
INT 2F C - DOS 5+ TASK SWITCHER - IDENTIFY INSTANCE DATA
    AX = 4B05h
    ES:BX = 0000h:0000h
    CX:DX -> task switcher entry point (see AX=4B02h)
Return: ES:BX -> startup info structure (see below) or 0000h:0000h
Notes:    called by task switcher
    clients with instance data should hook this call, pass it through to
      the previous handler with unchanged registers using a simulated
      interrupt.  On return, the client should create a startup info
      structure (see below), store the returned ES:BX in the "next"
      field, and return the address of the created structure in ES:BX
    all MS-DOS function calls are available from within this call
SeeAlso: AX=1605h,AX=160Bh,AX=4B02h

Format of startup info structure:
Offset    Size    Description
 00h  2 BYTEs    major, minor version of info structure (03h,00h)
 02h    DWORD    pointer to next startup info structure or 0000h:0000h
 06h    DWORD    0000h:0000h (ignored)
 0Ah    DWORD    ignored
 0Eh    DWORD    pointer to instance data records

Format of one instance data record in array:
Offset    Size    Description
 00h    DWORD    address of instance data (end of array if 0000h:0000h)
 04h    WORD    size of instance data
--------W-2F4B20-----------------------------
INT 2F - MS Windows 3 - WIN.COM - SET PROGRAM TO EXECUTE ON EXIT
    AX = 4B20h
Return: AX = 0000h if successful
        DX:CX -> 256-byte buffer for pathname and commandline (see below)
Note:    when the Windows function ExitWindows is called with an exit code of
      44h, WIN.COM executes the program specified in the returned buffer
      and then restarts Windows

Format of buffer:
Offset    Size    Description
 00h 128 BYTEs    ASCIZ pathname of program to execute
 80h 128 BYTEs    commandline for program
--------p-2F4C-------------------------------
INT 2F U - Advanced Power Management
    AH = 4Ch
    AL = function
        00h version check
        01h suspend system requested
        FFh suspend/resume battery notification
    ???
Return: ???
----------2F4D-------------------------------
INT 2F U - ???
    AH = 4Dh
    ???
Return: ???
Note:    reportedly called by Kana Kanji Converter and MSKK
--------N-2F4E53BL00-------------------------
INT 2F - SilverNET v2+ - INSTALLATION CHECK
    AX = 4E53h ("NS")
    BL = 00h (function "installation check")
    BH = module ID (see below)
Return: AX = 0000h if specified module installed
    BX = 4E53h if installed
Program: SilverNET is an SMB-compatible peer-to-peer NOS for DOS or
      Windows systems, by Net-Source, Inc. of Santa Clara, CA.
SeeAlso: AX=4E53h/BL=01h,AX=4E53h/BL=02h,AX=B800h,AX=B809h

Values for module ID:
 01h    SilverCACHE
 02h    Workstation
 03h    NetBIOS
 04h    Peer
 20h    NS Share
 80h    NetWare help TSR
--------N-2F4E53BL01-------------------------
INT 2F - SilverNET - GET RUNTIME PARAMETER
    AX = 4E53h ("NS")
    BL = 01h (function "get runtime parameter")
    BH = module ID (see AX=4E53h/BL=00h)
    CX = parameter index (see below)
Return: AX = WORD value at specified index
Desc:    retrieve a word of data from the specified SilverNET module

Values for Peer parameter index (* = read-only):
 00h *    maximum outstanding SMB buffers
 02h *    maximum logged-in nodes
 04h *    number of shareable resources
 06h *    number of characters to print per time slice
 08h *    number of printers that can be shared
 0Ah *    number of nodes logged in
 0Ch *    number of files to allow opened
 0Eh    how fast to despool (/PSLICE)
 10h    audit flag
 24h *    far pointer to resource table (each resource is 96 bytes in length)
 32h *    far pointer to SFT (internal if SilverNET files > CONFIG.SYS files,
    else DOS SFT)
 36h    spool flag
    bit 0: LPT1 needs despooling
    bit 1: LPT2 needs despooling
    bit 2: LPT2 needs despooling
    bit 4: COM1 needs despooling
    bit 5: COM2 needs despooling
    bit 6: COM3 needs despooling

Values for NS Share parameter index (* = read-only):
 00h    version number (high byte = minor, low byte = major)
 10h *    segment of first lock record (other records in consecutive paragraphs)
    (if PSP field = 0000h, lock record is free)
 12h *    maximum possible number of lock records
 14h *    starting segment of sharing buffer
    (NS Share's sharing records are identical to DOS SHARE except that
    fields which are normally offsets into SHARE are segment numbers)
 18h *    size of sharing buffer in paragraphs
 1Ah *    total free paragraphs in sharing buffer
 1Ch *    current number of shared files
 1Eh *    current number of locked records

Values for Workstation parameter index (* = read-only):
 00h    version number (high byte = minor, low byte = major)
 02h *    size of each network buffer for file operations
 04h *    number of redirector file buffers
 06h *    size of each print cache buffer
 08h *    number of network LPT printers
 0Ch    flush time in ticks (idle time on network printer before flushing)
 0Eh    (16 WORDs) last active time for each printer
 2Eh *    stub segment if program split into two parts
 60h    receive name number for datagram listens
 62h *    18-byte machine name
 74h *    LASTDRIVE (01h = A:, etc.)
 7Ch    row number of message box on screen
 7Eh    message time in clock ticks
 82h *    number of network adapters in use
 84h    station ID broadcast flag (never set on redirectors)
 96h *    NetBIOS names left
 98h *    NCBs left
 9Ah *    sessions left
 A2h *    total number of network printers (LPT+COM)
 A4h *    number of serial network printers
 A8h *    segment containing file cache buffers
 AAh *    segment containing print cache buffers
 ACh *    bytes remaining free in HMA before program loaded
 AEh *    start of free memory in HMA
 B2h *    flag: using HMA
--------N-2F4E53BL02-------------------------
INT 2F - SilverNET - SET RUNTIME PARAMETERS
    AX = 4E53h ("NS")
    BL = 02h (function "set runtime parameters")
    BH = module ID (see AX=4E53h/BL=00h)
    CX = parameter index (see AX=4E53h/BL=01h)
    DX = new value for specified parameter
Desc:    set a WORD value in the specified SilverNET module
Note:    not all indexed parameters are writable; modifying a read-only
      parameter can result in system crashes
SeeAlso: AX=4E53h/BL=00h,AX=4E53h/BL=01h
--------p-2F53-------------------------------
INT 2F U - POWER.EXE - APM event broadcasting???
    AH = 53h
    AL = event???
        05h CPU idle
        0Bh PM event broadcast API
Return: ???
Note:    called by MS Windows 3.1 POWER.DRV; hooked by MS Mouse driver v8.20+
      and PC-Cache v8.0
SeeAlso: AX=530Bh,AH=54h,INT 33/AX=002Fh
--------p-2F530B-----------------------------
INT 2F U - ??? (MOUSEPWR.COM, others) - ???
    AX = 530Bh
    BX = subfunction
        0003h ???
        0004h ???
    ???
Return: ???
Note:    it appears that subfunction 0003h reads or restores the current mouse
      settings (the MS Mouse driver hooks AX=530Bh), and 0004h might be
      the converse
--------p-2F5400-----------------------------
INT 2F U - POWER.EXE - INSTALLATION CHECK
    AX = 5400h
Return: AX = POWER.EXE version (AH = major, AL = minor) if installed
    BX = 504Dh ("PM")
    CF clear
Note:    called by MS Windows 3.1 POWER.DRV
SeeAlso: AH=53h,AX=5401h,AX=5402h,AX=5481h,AX=5482h
--------p-2F5401-----------------------------
INT 2F U - POWER.EXE - GET/SET POWER STATUS
    AX = 5401h
    BX = function
        0000h get status
        Return: BL = power management status
                bit 0: CPU idle
                bit 1: ???
        ???
Return: AX = function status
        0000h success
        else  error code
Note:    called by MS Windows 3.1 POWER.DRV
SeeAlso: AH=53h,AX=5400h,AX=5402h,AX=5403h
--------p-2F5402-----------------------------
INT 2F U - POWER.EXE - GET/SET IDLE DETECTION STRATEGY
    AX = 5402h
    BH = subfunction
        00h get
        other set
        BL = detection strategy (00h-0Fh or FFh)
Return: BX = current/new detection strategy
SeeAlso: AH=53h,AX=5400h,AX=5401h,AX=5481h,AX=5482h
--------p-2F5403-----------------------------
INT 2F U - POWER.EXE - GET/SET ADVANCED POWER MANAGEMENT SETTING
    AX = 5403h
    BX = new power management setting or 0000h to get current setting
Return: AX = status
        0000h successful
        BX = power management setting (see below)
        other error code
SeeAlso: AX=5401h,AX=5480h

Values for power management setting:
 0001h-0005h "min"
 0006h         "reg"
 0007h-0008h "max"
--------t-2F5453-----------------------------
INT 2F - TesSeRact RAM-RESIDENT PROGRAM INTERFACE
    AX = 5453h
    BX = subfunction
        00h installation check
        CX = 0000h
        DS:SI -> 8-char blank-padded name
        Return: AX = FFFFh installed
                CX = ID number of already-installed copy
               = anything else, not installed
                CX = ID number for TSR when installed
        01h get user parameters
        CX = TSR ID number
        Return: AX = 0000h successful
               ES:BX -> user parameter block (see below)
               = nonzero failed
        02h check if hotkey in use
        CL = scan code of hot key
        Return: AX = FFFFh hot key conflicts with another TSR
                 otherwise safe to use the hotkey
        03h replace default critical error handler
        CX = TSR ID number
        DS:SI -> new routine for INT 24h
        Return: AX = nonzero, unable to install new handler
        04h get internal data area
        CX = TSR ID number
        Return: AX = 0000h
                ES:BX -> TSR's internal data area (see below)
               = nonzero, TSR not found
        05h set multiple hot keys
        CX = TSR ID number
        DL = number of additional hot keys to allocate
        DS:SI -> table of hot keys
            BYTE  hotkey scan code
            BYTE  hotkey shift state
            BYTE  flag value to pass to TSR (nonzero)
        Return: AX = nonzero, unable to install hot keys
        06h - 0Fh reserved
        10h enable TSR
        CX = TSR ID number
        Return: AX = nonzero, unable to enable
        11h disable TSR
        CX = TSR ID number
        Return: AX = nonzero, unable to disable
        12h unload TSR
        CX = TSR ID number
        Return: AX = nonzero, invalid TSR number
        Note: if any interrupts used by TSR have been grabbed by
            another TSR, the TesSeRact routines will wait until
            it is safe to remove the indicated TSR from memory
        13h restart TSR
        CX = TSR ID number of TSR which was unloaded but is still in
             memory
        Return: AX = nonzero, unable to restart TSR
        14h get status word
        CX = TSR ID number
        Return: AX = FFFFh invalid ID number
               = other, successful
                BX = bit flags
        15h set status word
        CX = TSR ID number
        DX = new bit flags
        Return: AX = nonzero, unable to set status word
        16h get INDOS state at popup
        CX = TSR ID number
        Return: AX = 0000h successful
                BX = value of INDOS flag
        17h - 1Fh reserved
        20h call user procedure
        CX = TSR ID number
        ES:DI -> user-defined data
        Return: AX = 0000h successful
        21h stuff keystrokes into keyboard buffer
        CX = TSR ID number
        DL = speed
            00h stuff keystrokes only when buffer is empty
            01h stuff up to four keystrokes per clock tick
            02h stuff up to 15 keystrokes per clock tick
        DH = scan code flag
            if zero, buffer contains alternating ASCII and scan codes
            if nonzero, buffer contains only ASCII codes
        SI = number of keystrokes
        ES:DI -> buffer to stuff
        Return: AX = 0000h success
                 F0F0h user aborted with ^C or ^Break
                 other unable to stuff keystrokes
        22h (v1.10) trigger popup
        CX = TSR ID number
        Return: AX = 0000h success, TSR will either pop up or beep to
                   indicate that it is unable to pop up
                 nonzero invalid ID number
        23h (v1.10) invoke TSR's background function
        CX = TSR ID number
        Return: AX = 0000h success
                 FFFFh not safe to call background function
                 nonzero invalid ID number
        24h - 2Fh reserved
Notes:    Borland's THELP.COM popup help system for Turbo Pascal and Turbo C
      (versions 1.x and 2.x only) fully supports the TesSeRact API, as
      do the SWAP?? programs by Innovative Data Concepts.
    AVATAR.SYS supports functions 00h and 01h (only the first three fields
      of the user parameter block) using the name "AVATAR  "
SeeAlso: AX=CAFEh,INT 16/AX=55FFh,INT 2D"AMIS"
Index:    installation check;TesSeRact TSR interface|uninstall;TesSeRact

Values for TesSeract names:
 "AVATAR  "    AVATAR.SYS
 "QeditTSR"    TSR version of SemWare's Qedit editor
 "SCRNBLNK"    Trusted Access screen blanker

Format of User Parameter Block:
Offset    Size    Description
 00h  8 BYTEs    blank-padded TSR name
 08h    WORD    TSR ID number
 0Ah    DWORD    bitmap of supported functions
 0Eh    BYTE    scan code of primary hotkey
            00h = pop up when shift states match
            FFh = no popup (if shift state also FFh)
 0Fh    BYTE    shift state of primary hotkey
            FFh = no popup (if scan code also FFh)
 10h    BYTE    number of secondary hotkeys
 11h    DWORD    pointer to extra hotkeys set by func 05h
 15h    WORD    current TSR status flags
 17h    WORD    PSP segment of TSR
 19h    DWORD    DTA for TSR
 1Dh    WORD    default DS for TSR
 1Fh    DWORD    stack at popup
 23h    DWORD    stack at background invocation
Index:    hotkeys;TesSeRact TSR interface

Format of TSR internal data area:
Offset    Size    Description
 00h    BYTE    revision level of TesSeRact library
 01h    BYTE    type of popup in effect
 02h    BYTE    INT 08 occurred since last invocation
 03h    BYTE    INT 13 occurred since last invocation
 04h    BYTE    active interrupts
 05h    BYTE    active soft interrupts
 06h    BYTE    DOS major version
 07h    BYTE    how long to wait before popping up
 08h    DWORD    pointer to INDOS flag
 0CH    DWORD    pointer to DOS critical error flag
 10h    WORD    PSP segment of interrupted program
 12h    WORD    PSP segment of prog interrupted by INT 28
 14h    DWORD    DTA of interrupted program
 18h    DWORD    DTA of program interrupted by INT 28
 1Ch    WORD    SS of interrupted program
 1Eh    WORD    SP of interrupted program
 20h    WORD    SS of program interrupted by INT 28
 22h    WORD    SP of program interrupted by INT 28
 24h    DWORD    INT 24 of interrupted program
 28h  3 WORDs    DOS 3+ extended error info
 2Eh    BYTE    old BREAK setting
 2Fh    BYTE    old VERIFY setting
 30h    BYTE    were running MS WORD 4.0 before popup
 31h    BYTE    MS WORD 4.0 special popup flag
 32h    BYTE    enhanced keyboard call in use
 33h    BYTE    delay for MS WORD 4.0
11 times (for INTs 08h,09h,13h,16h,1Ch,21h,28h,2Fh,1Bh,23h, and 24h):
    DWORD    old interrupt vector
    BYTE    interrupt number
    WORD    offset in TesSeRact code segment of new interrupt handler
--------p-2F5480-----------------------------
INT 2F U - POWER.EXE - GET/SET ???
    AX = 5480h
    BX = direction
        0000h get
        other set
    CX = size of buffer (at least 0010h)
    DS:SI -> buffer
Return: AX = status
        0000h successful
        other error code
SeeAlso: AX=5400h,AX=5481h,AX=548Fh
--------p-2F5481-----------------------------
INT 2F U - POWER.EXE - GET STATISTICS
    AX = 5481h
    BX = ??? (0000h or 0001h)
    CX = length of buffer
    DS:SI -> buffer for statistics (see below)
Return: AX = status
        0000h successful
        else  error code
SeeAlso: AH=53h,AX=5400h,AX=5480h,AX=5402h,AX=5482h

Format of statistics:
Offset    Size    Description
 00h    DWORD    total ???
 04h    DWORD    ??? during which CPU was idle (divide by previous to get idle
            rate)
--------p-2F5482-----------------------------
INT 2F U - POWER.EXE - GET/SET APM POLLING FREQUENCY
    AX = 5482h
    BX = new polling frequency or 0000h to get current frequency
Return: AX = 0000h (successful)
    BX = current frequency if BX=0000h on entry
SeeAlso: AH=53h,AX=5400h,AX=5401h,AX=5480h,AX=5481h,AX=548Fh
--------p-2F548F-----------------------------
INT 2F U - POWER.EXE - GET/SET ???
    AX = 548Fh
    BX = ??? or 0000h to get current ???
Return: AX = 0000h (successful)
    BX = current ???
    CX = ???
SeeAlso: AX=5400h,AX=5480h,AX=5482h
--------l-2F5500-----------------------------
INT 2F U - DOS 5+ - COMMAND.COM INTERFACE
    AX = 5500h
Return: AX = 0000h if an instance of COMMAND.COM is already running
    DS:SI -> entry point table
Notes:    used to access the shareable portion of COMMAND.COM, which may have
      been moved into the HMA; only the primary COMMAND.COM retains this
      portion
    procedures called from a dispatcher in COMMAND's resident portion;
      most assume that the segment address of the resident portion is on
      the stack and are thus not of general use
SeeAlso: AX=5501h
--------l-2F5501-----------------------------
INT 2F U - DOS 5+ - ROM COMMAND.COM INTERFACE
    AX = 5501h
Return: ???
Note:    used to determine whether the caller is the first instance of ROM
      COMMAND.COM
SeeAlso: AX=5500h
--------R-2F5600DXFFFF-----------------------
INT 2F - INTERLNK - INSTALLATION CHECK
    AX = 5600h
    DX = FFFFh
    BL = instance number (00h = any, 01h = first loaded, etc.)
Return: AL = FFh if installed
        BL = instance number
        CX = ???
        DX = resident CS
SeeAlso: AX=5601h,AX=5602h
--------R-2F5601DXFFFF-----------------------
INT 2F - INTERLNK - CHECK IF REDIRECTED DRIVE
    AX = 5601h
    DX = FFFFh
    BH = drive number (0=A:)
    BL = 00h
Return: (as for AL=00h if redirected drive)
SeeAlso: AX=5600h
--------R-2F5602DXFFFF-----------------------
INT 2F - INTERLNK - GET ???
    AX = 5602h
    DX = FFFFh
Return: CX = ???
SeeAlso: AX=5600h
----------2F57-------------------------------
INT 2F U - ???
    AH = 57h
    ???
Return: ???
Note:    reportedly used by Iomega Corp.
--------v-2F6282-----------------------------
INT 2F U - PC Tools v7.0+ VDEFEND, VSAFE, VWATCH, DATAMON - SET ??? ADDRESS
    AX = 6282h
    CX:DX -> ??? or 0000h:0000h
    DI = segment of ??? record (see below) or 0000h/FFFFh to ignore
Return: BX = 0062h
Note:    if CX:DX = 0000h:0000h on entry, the ??? address is not changed
      (DATAMON only)
SeeAlso: INT 13/AH=FAh"VSAFE",INT 21/AH=FAh"VDEFEND"

Format of record:
Offset    Size    Description
 00h    DWORD    ???
 04h    WORD    offset of ??? in record's segment
        VSAFE 2.0 sets byte at +01h to 56h or 58h
        VWATCH 2.1 sets byte at +02h to 56h or 58h
 06h  2 BYTEs    ???
 08h    BYTE    ??? (01h/other)
--------v-2F6284BX0000-----------------------
INT 2F U - PC Tools v7-8 DATAMON, v9+ DPROTECT    - INSTALLATION CHECK
    AX = 6284h
    BX = 0000h
    CX = 0000h
Return: AX = segment of resident code
    BX = 5555h
    CX = 5555h
--------v-2F6284BX0001-----------------------
INT 2F U - PC Tools v7-8 DATAMON, v9+ DPROTECT - GET ???
    AX = 6284h
    BX = 0001h
    CX = 0001h
Return: AX:BX -> ??? data (see below)
    CX = BX

Format of data for v9.0:
Offset    Size    Description
 00h  5 BYTEs    ???
 05h    WORD    resident code segment (may be segment of DWORD at +03h)
 07h    DWORD    -> FAR function to sound alert tone
    ???
--------v-2F6284BX0002-----------------------
INT 2F U - PC Tools v7-8 DATAMON, v9+ DPROTECT - GET OPTIONS
    AX = 6284h
    BX = 0002h
    CX = 0002h
Return: AX = options (see below)
    BX = ??? (0000h for v9)
    CX = AX
    DX = BX

Bitfields for options:
 bit 14    using Delete Tracker
 bit 13    using Delete Sentry
 bit 12    disabled
 bit 1    ???
--------v-2F6284BX0003-----------------------
INT 2F U - PC Tools v7-8 DATAMON, v9+ DPROTECT - SET ??? FLAGS
    AX = 6284h
    BX = 0003h
    CX = flags
        bit 12: disable DATAMON/DPROTECT
        bit 10: ???
        bit     5: ???
        bit     3: ???
    DX = flags
        bit 15: ???
Note:    v9 DPROTECT only checks bit 12 of CX, and ignores DX entirely
--------v-2F6284BX0004-----------------------
INT 2F U - PC Tools v8 DATAMON, v9+ DPROTECT - ???
    AX = 6284h
    BX = 0004h
    CX = 0004h
Return: AX = 5555h
    BX = ??? (0800h)
    CX = ??? (FCCCh for v8, FCCBh for v9)
--------V-2F6400-----------------------------
INT 2F - SCRNSAV2.COM - INSTALLATION CHECK
    AX = 6400h
Return: AL = 00h not installed
         FFh installed
Program: SCRNSAV2.COM is a screen saver for PS/2s with VGA by Alan Ballard
SeeAlso: INT 10/AX=5555h
Index:    screen saver;SCRNSAV2
--------N-2F7000-----------------------------
INT 2F - License Service API - INSTALLATION CHECK
    AX = 7000h
    CX = license server index (0000h to 001Fh)
Return: AL = status
        00h not installed
        FFh installed
Notes:    The License Service API is being maintained by Microsoft but is being
      supported by a large number of companies including Apple, Banyan,
      DEC, HP, Lotus, Microsoft, Novell, Software Publishers Association,
      and Wordperfect (not a complete list!)
    Each license service provider must search for the next free index
      slot to use
SeeAlso: AX=7001h,AX=7003h,AX=7004h,AX=7005h
--------N-2F7001-----------------------------
INT 2F - License Service API - REQUEST LICENSE
    AX = 7001h
    CX = license server index (0000h to 001Fh)
    DS:DX -> SLSREQUEST structure (see below)
Return: AX = status
        0000h success
        else  provider error code
    ES:BX = provider specific handle for the license context
SeeAlso: AX=7002h,AX=7004h,AX=7005h

Format of SLSREQUEST structure:
Offset    Size    Description
 00h    DWORD    (return) status code
 04h    DWORD    (return) handle identifying context
 08h    DWORD    (call) address of Publisher string
 0Ch    DWORD    (call) address of Product string
 10h    DWORD    (call) address of Version string
 14h    DWORD    units required
 18h    DWORD    address of comment string
 1Ch    DWORD    address of SLSCHALLENGE structure (see below)

Format of SLSCHALLENGE structure:
Offset    Size    Description
 00h    DWORD    algorithm (currently always 1)
 04h    DWORD    secret to be challenged (1-255)
 08h    DWORD    size of challenge in bytes (1-255)
 0Ch  N BYTEs    challenge data
--------N-2F7002-----------------------------
INT 2F - License Service API - RELEASE LICENSE
    AX = 7002h
    CX = license server index (0000h to 001Fh)
    DS:DX -> SLSRELEASE structure (see below)
    ES:BX = provider specific handle for the license context
Return: AL = status
        00h not installed
        FFh installed
SeeAlso: AX=7001h,AX=7005h

Format of SLSRELEASE structure:
Offset    Size    Description
 00h    DWORD    handle indentifying license context
 04h    DWORD    total units consumed
 08h    DWORD    address of comment string
--------N-2F7003-----------------------------
INT 2F - License Service API - UPDATE
    AX = 7003h
    CX = license server index (0000h to 001Fh)
    DS:DX -> SLSUPDATE structure
    ES:BX = provider specific handle for the license context
Return: AL = status
        00h not installed
        FFh installed
SeeAlso: AX=7004h,AX=7005h

Format of SLSUPDATE structure:
Offset    Size    Description
 00h    DWORD    (return) status code
 04h    DWORD    (call) handle identifying license context
 08h    DWORD    (call) total units consumed
 0Ch    DWORD    additional units required
 10h    DWORD    address of comment string
 14h    DWORD    address of SLSCHALLENGE structure (see AX=7001h)
--------N-2F7004-----------------------------
INT 2F - License Service API - GET ERROR
    AX = 7004h
    CX = license server index (0000h to 001Fh)
    DS:DX -> SLSGETERROR structure (see below)
    ES:BX = provider specific handle for the license context
Return: AL = status
        00h not installed
        FFh installed
SeeAlso: AX=7000h,AX=7001h

Format of SLSGETERROR structure:
Offset    Size    Description
 00h    DWORD    (return) status code
 04h    DWORD    handle identifying license context
 08h    DWORD    error code
 0Ch    DWORD    buffer size in bytes
 10h  N BYTEs    data buffer
--------N-2F7005-----------------------------
INT 2F - License Service API - QUERY LICENSE
    AX = 7005h
    CX = license server index (0000h to 001Fh)
    DS:DX -> SLSQUERY structure (see below)
    ES:BX = provider specific handle for the license context
Return: AL = status
        00h not installed
        FFh installed
SeeAlso: AX=7001h,AX=7002h

Format of SLSQUERY structure:
Offset    Size    Description
 00h    DWORD    (return) status code
 04h    DWORD    handle identifying license context
 08h    DWORD    information index
 0Ch    DWORD    buffer size in bytes
 10h  N BYTEs    data buffer
--------d-2F7200-----------------------------
INT 2F - SRDISK v1.30 - INSTALLATION CHECK
    AX = 7200h
Return: AL = FFh if installed
        ES = segment of device driver header (see below)
Program: SRDISK is a freeware resizeable RAMdisk by Marko Kohtala

Format of device driver header:
Offset    Size    Description
 00h 10 BYTEs    same as standard device driver header (see INT 21/AH=52h)
 0Ah    BYTE    number of subunits (drives) supported by driver
 0Bh  3 BYTEs    signature "SRD"
 0Eh  4 BYTEs    memory type string (currently only "XMS ")
 12h  4 BYTEs    ASCII driver version string "N.NN"
 16h    BYTE    00h
 17h    BYTE    configuration format version (currently 00h)
 18h    WORD    offset of drive configuration data
--------N-2F7A00-----------------------------
INT 2F - Novell NetWare - LOW-LEVEL API (IPX) INSTALLATION CHECK
    AX = 7A00h
Return: AL = 00h not installed
       = FFh installed
        ES:DI -> FAR entry point for routines accessed exclusively
            through INT 7A in NetWare versions through 2.0a.  Call
            with same values as INT 7A
SeeAlso: AX=7AFFh/BX=0000h,AX=D800h,INT 64"Novell",INT 7A"Novell"
--------N-2F7A10-----------------------------
INT 2F U - Novell NetWare - TBMI v1.1+ - GET TBMI STATUS
    AX = 7A10h
Return: DH = major TBMI version number
    DL = minor TBMI version number (01h for v1.1)
    CX = segment address of TBMI resident part
    BX = status word of TBMI (see below)
Note:    TBMI is the Task-Switched Buffer Manager Interface
SeeAlso: AX=7A11h,AX=7A12h,AX=7A13h,AX=7A14h

Bitfields for status word:
 bit 0    INT2F intercepted by TBMI
 bit 1    INT7A intercepted by TBMI
 bit 2    INT64 intercepted by TBMI
 bits 3-14 reserved or unused ???
 bit 15 outstanding task ID was detected
--------N-2F7A11-----------------------------
INT 2F U - Novell NetWare - TBMI v1.1+ - GET INT2F HANDLERS
    AX = 7A11h
Return: ES:BX -> old INT 2F handler
    DS:DX -> TBMI INT 2F handler
SeeAlso: AX=7A10h,AX=7A12h,AX=7A13h,AX=7A1Ah
--------N-2F7A12-----------------------------
INT 2F U - Novell NetWare - TBMI v1.1+ - GET INT64 HANDLERS
    AX = 7A12h
Return: ES:BX -> old INT 64 handler
    DS:DX -> TBMI INT 64 handler
SeeAlso: AX=7A10h,AX=7A11h,AX=7A13h
--------N-2F7A13-----------------------------
INT 2F U - Novell NetWare - TBMI v1.1+ - GET INT7A HANDLERS
    AX = 7A13h
Return: ES:BX -> old INT 7A handler
    DS:DX -> TBMI INT 7A handler
SeeAlso: AX=7A10h,AX=7A11h,AX=7A12h
--------N-2F7A14-----------------------------
INT 2F U - Novell NetWare - TBMI v1.1+ - GET STATISTICS
    AX = 7A14h
    CX = statistic to retrieve
        0000h available diagnostic functions???
        Return: CX = maximum available function??? (000Ch for v2.0)
        0001h buffers in use
        Return: CX = TBMI buffers currently in use
        0002h maximum buffers used
        Return: CX = maximum number of buffers ever in use
        0003h unavailable buffers
        Return: CX = count of unavailable TBMI buffers
        0004h old interrupt usage
        Return: CX = TBMI accesses to intercepted old vectors INT 2F,
                INT 64, and INT 7A
        0005h far call usage
        Return: CX = TBMI accesses to IPX/SPX far call handler (not
                including internal accesses)
        0006h task buffering
        Return: CX = TBMI task buffering status (enabled/disabled or
                disable/enable switch count???)
        0007h current task ID
        Return: CX = TBMI current task ID number (0000h if ???)
        0008h outstanding ID count
        Return: CX = number of outstanding TBMI IDs
        0009h configured ECBs
        Return: CX = number of TBMI Event Control Blocks configured
        000Ah configured data ECBs
        Return: CX = number of TBMI data ECBs configured
        000Bh configured sockets
        Return: CX = number of TBMI sockets configured (from NETCFG)
        000Ch current sockets
        Return: CX = number of TBMI sockets currently in use
Return: BX = maximum supported subfunction (000Ch)
SeeAlso: AX=7A10h
--------N-2F7A15-----------------------------
INT 2F OU - Novell NetWare - TBMI v1.1 only - RESET ???
    AX = 7A15h
Return: BX = new value of ???
Desc:    set ??? to its default value
Note:    this call is a NOP under TBMI v2.0 (TBMI2)
SeeAlso: AX=7A17h
--------N-2F7A16-----------------------------
INT 2F OU - Novell NetWare - TBMI v1.1 only - ???
    AX = 7A16h
    CX = ???
    ???
Return: ???
Note:    this call is a NOP under TBMI v2.0 (TBMI2)
--------N-2F7A17-----------------------------
INT 2F OU - Novell NetWare - TBMI v1.1 only - ???
    AX = 7A17h
    ???
Return: BX = old value of ???
    CX = new value of ???
Note:    this call is a NOP under TBMI v2.0 (TBMI2)
SeeAlso: AX=7A15h
--------N-2F7A18-----------------------------
INT 2F U - Novell NetWare - TASKID v1.0 - INSTALLATION CHECK
    AX = 7A18h
Return: AL = FFh if installed
        BX = configuration flags (see below)
        CX = resident code segment
SeeAlso: AX=7A10h

Bitfields for configuration flags:
 bit 0    INT 2F hooked
 bit 3    INT 08 hooked
 other    unused
--------N-2F7A19-----------------------------
INT 2F U - Novell NetWare - TASKID v1.0 - GET INT 08 HANDLERS
    AX = 7A19h
Return: AL = FFh
    DS:DX -> TASKID INT 08 handler
    ES:BX -> original INT 08 handler
--------N-2F7A1A-----------------------------
INT 2F U - Novell NetWare - TASKID v1.0 - GET INT 2F HANDLERS
    AX = 7A1Ah
Return: AL = FFh
    DX:DX -> TASKID INT 2F handler
    ES:BX -> original INT 2F handler
SeeAlso: AX=7A11h,AX=7A19h
--------N-2F7A1B-----------------------------
INT 2F U - Novell NetWare - TASKID v1.0 - GET DIAGNOSTICS INFORMATION
    AX = 7A1Bh
    CX = desired information
        0000h supported functions
        0001h TASKID ID number
        Return: CX = ID number
        0002h set-ID count
        Return: CX = ID set count
Return: AL = FFh
    BX = highest supported subfunction number (0002h)
SeeAlso: AX=7A14h,AX=7A18h
--------N-2F7A1C-----------------------------
INT 2F U - Novell NetWare - TBMI v1.1+ - ???
    AX = 7A1Ch
    BP = ???
    CX:DX = ???
Return: AX = 70FFh
--------N-2F7A1D-----------------------------
INT 2F U - Novell NetWare - TBMI v1.1+ - ???
    AX = 7A1Dh
    ???
Return: ES = ???
    ???
    SI destroyed
--------N-2F7A1E-----------------------------
INT 2F U - Novell NetWare - TBMI v1.1+ - ???
    AX = 7A1Eh
    ES:SI -> ???
    ???
Return: ???
--------N-2F7A20BX0000-----------------------
INT 2F - Novell NetWare - Advanced NetWare 4.0 DOS Requester - GET CALL ADDRESS
    AX = 7A20h
    BX = 0000h
Return: AX = 0000h on success (installed)
        ES:BX -> far call address for DOS Requester
Notes:    the DOS Requester replaces the NetWare Shell (ANETx, NETx) on
      NetWare LAN's as of the release of Advanced NetWare 4.0 (1993).  It
      is backward compatible with NetWare 2.1x through 3.11 servers as
      well.     Note that there was a NetWare 4.0 in the early 1980's, which
      can cause confusion.
    this call is used as the installation check by VLM.EXE, which is the
      loader for all the modules of the DOS Requester
Index:    installation check;NetWare 4.0 DOS Requester
--------N-2F7A20BX0001-----------------------
INT 2F - Novell NetWare - DOS Requester v1.03 - GET ??? ENTRY POINT
    AX = 7A20h
    BX = 0001h
Return: AX = 0000h
    ES:BX -> ??? entry point
--------N-2F7A20BX0002-----------------------
INT 2F - Novell NetWare - DOS Requester v1.03 - GET ??? ADDRESS
    AX = 7A20h
    BX = 0002h
Return: AX = 0000h
    ES:BX -> ??? data
--------N-2F7A20BX0003-----------------------
INT 2F - Novell NetWare - DOS Requester v1.03 - GET ???
    AX = 7A20h
    BX = 0003h
Return: AX = 0000h
    ES:BX -> ???
--------N-2F7A20BX0004-----------------------
INT 2F - Novell NetWare - DOS Requester v1.03 - GET ??? ADDRESS
    AX = 7A20h
    BX = 0004h
Return: AX = 0000h
    ES:BX -> ??? data (see below)

Format of data:
Offset    Size    Description
 00h    DWORD    pointer to ??? (code)
 04h  4 BYTEs    ???
 08h    DWORD    pointer to ??? (code)
    ???
--------N-2F7A20BX0005-----------------------
INT 2F - Novell NetWare - DOS Requester v1.03 - GET ??? ENTRY POINT
    AX = 7A20h
    BX = 0005h
Return: AX = 0000h
    ES:BX -> ??? entry point
--------N-2F7A20BX0006-----------------------
INT 2F - Novell NetWare - DOS Requester v1.03 - GET ??? ENTRY POINT
    AX = 7A20h
    BX = 0006h
Return: AX = 0000h
    ES:BX -> ??? entry point (RETF in v1.03)
--------N-2F7A20BX0007-----------------------
INT 2F - Novell NetWare - DOS Requester v1.03 - GET ??? ENTRY POINT
    AX = 7A20h
    BX = 0007h
Return: AX = 0000h
    ES:BX -> ??? entry point (RETF in v1.03)
--------N-2F7A20BX0008-----------------------
INT 2F - Novell NetWare - DOS Requester v1.03 - GET ??? ENTRY POINT
    AX = 7A20h
    BX = 0008h
Return: AX = 0000h
    ES:BX -> ??? entry point (RETF in v1.03)
--------N-2F7A20BX0080-----------------------
INT 2F - Novell NetWare - DOS Requester v1.03 - GET ??? ENTRY POINT
    AX = 7A20h
    BX = 0080h
Return: AX = 0000h
    ES:BX -> ??? entry point (RETF in v1.03)
Note:    this function is identical to AX=7A20h/BX=0006h in v1.03
--------N-2F7A20BX0081-----------------------
INT 2F - Novell NetWare - DOS Requester v1.03 - GET ??? ENTRY POINT
    AX = 7A20h
    BX = 0081h
Return: AX = 0000h
    ES:BX -> ??? entry point (RETF in v1.03)
Note:    this function is identical to AX=7A20h/BX=0007h in v1.03
--------N-2F7A20BX0082-----------------------
INT 2F - Novell NetWare - DOS Requester v1.03 - GET ??? ENTRY POINT
    AX = 7A20h
    BX = 0082h
Return: AX = 0000h
    ES:BX -> ??? entry point (RETF in v1.03)
Note:    this function is identical to AX=7A20h/BX=0008h in v1.03
--------N-2F7A40-----------------------------
INT 2F - Novell NetWare - TCP/IP Protocol Stack - INSTALLATION CHECK
    AX = 7A40h
Return: AX = 7AFFh if installed
        BX = ???
        bit 0: ???
        bit 1: ???
        bits 15-2: ???
        CX = version (CH=major, CL=minor)
        DX = 0000h
        ES:DI -> entry point for TCP/IP stack (see below)
Notes:    Novell's LAN Workplace for DOS TCPIP.EXE also supports this interface
    this function is also supported by the Beame&Whiteside BWLWP40 shim,
      but it only returns AL and ES:DI, and does not support AX=7A41h
SeeAlso: AX=7A41h,INT 60"Excelan"

Call entry point with:
    ES:SI -> parameter block (see below)
    ???
Return: ES:SI parameter block updated

Format of parameter block:
Offset    Size    Description
 00h    DWORD    ???
 04h    WORD    (return) ???
 06h    WORD    (return) ???
 08h  4 BYTEs    ???
 0Ch    BYTE    flags???
 0Dh  7 BYTEs    ???
 14h    BYTE    (return) ???
 15h    BYTE    (call) ??? number, bit 7 set if ???
 16h    BYTE    ???
 17h    BYTE    (return) result or error code
    ???
--------N-2F7A41-----------------------------
INT 2F - Novell NetWare - TCP/IP Protocol Stack - WINDOWS SUPPORT???
    AX = 7A41h
    ES:DI -> FAR entry point for ??? (will be called with BX=1,2,3,4)
Return: AX = 7AFFh if supported
        BX = ??? (see AX=7A40h)
        CX = version (CH=major, CL=minor)
        DX = 0000h
        ES:SI -> DWORD containing passed value of ES:DI
        ES:DI -> entry point for TCP/IP stack
Notes:    Novell's LAN Workplace for DOS TCPIP.EXE also supports this interface
    the pointer which is set to ES:DI is cleared to 0000h:0000h when
      a Windows exit broadcast is received
SeeAlso: AX=7A40h
--------N-2F7A42-----------------------------
INT 2F - Novell NetWare - TCPIP.EXE v4.1 - GET ??? ENTRY POINT
    AX = 7A42h
Return: AX = 7AFFh if supported
        ES:DI -> ??? entry point (see below)

Call entry point with:
    DX = ???
    ES:DI -> ??? (see below)
Return: AX = 0000h
    other registers destroyed

Format of data buffer:
Offset    Size    Description
 00h    WORD    offset of WORD ??? or 0000h
 02h    WORD    offset of DWORD ??? or 0000h
 04h    WORD    offset of DWORD ??? or 0000h
--------N-2F7A43-----------------------------
INT 2F - Novell NetWare - TCPIP.EXE v4.1 - ???
    AX = 7A43h
Return: AX = 7AFFh if supported
        DX = offset of ???
SeeAlso: AX=7A44h
--------N-2F7A44-----------------------------
INT 2F - Novell NetWare - TCPIP.EXE v4.1 - ???
    AX = 7A44h
    DX = offset of ??? (see AX=7A43h)
Return: AX = 7AFFh if supported
SeeAlso: AX=7A43h
--------N-2F7A4C-----------------------------
INT 2F - Novell NetWare - TCPIP.EXE v4.1 - GET ???
    AX = 7A4Ch
Return: AX = 7AFFh if supported
        BX = ??? (0037h)
        CX = ??? (001Ch)
--------N-2F7A4DBX0001-----------------------
INT 2F - Novell NetWare - ???
    AX = 7A4Dh
    BX = 0001h
    ES:DI -> ???
Return: AL = FFh if ???
        ES:DI -> ???
Note:    called by NETBIOS.EXE v3.01
--------N-2F7A4FBX0001-----------------------
INT 2F - Novell NetWare - SNMP.EXE - INSTALLATION CHECK
    AX = 7A4Fh
    BX = 0001h
Return: AX = 7AFFh if installed
--------N-2F7A4FBX0002-----------------------
INT 2F - Novell NetWare - SNMP.EXE - ???
    AX = 7A4Fh
    BX = 0002h
Return: AL = status
        4Fh if failed
        FFh if successful
--------N-2F7A80-----------------------------
INT 2F C - Novell NetWare - SHELL 3.01d BROADCAST - ABNORMAL EXIT
    AX = 7A80h
Return: nothing
Notes:    called on abnormal exit of the NetWare shell to notify other Novell
      TSRs that it is unsafe to call the shell in the future.
    must be passed through so that all interested programs see the exit
    on receiving this call, IPXODI clears an internal pointer to a
      default value; Novell's NETBIOS.EXE clears its INT 21h pointer to
      0000h:0000h and stops calling it
SeeAlso: AX=7A81h
--------N-2F7A81-----------------------------
INT 2F C - Novell NetWare - SHELL 3.01d BROADCAST - SET SHELL INT 21 HANDLER
    AX = 7A81h
    CX:DX -> shell's INT 21h entry point
Return: nothing
Notes:    the shell calls this function as it loads to allow interested TSRs
      and drivers to make a local copy of the shell's entry point
    must be passed through so that all interested programs see it
--------N-2F7A85-----------------------------
INT 2F C - Novell NetWare - shell 3.01 - BROADCAST INFORM
    AX = 7A85h
    CX = broadcast server number
Return: CX = 0000h if broadcast message handled by another program
    CX unchanged if broadcast not handled
--------N-2F7A90-----------------------------
INT 2F U - Novell NetWare - NETBIOS.EXE 3+ - INSTALLATION CHECK
    AX = 7A90h
Return: AL = 00h if present
        BX = ???
        CX = PSP segment of NETBIOS resident code
SeeAlso: AX=7AFEh
--------N-2F7AC1-----------------------------
INT 2F - LAN HiJack - LHR - DISABLE???
    AX = 7AC1h
Program: LAN HiJack is a NetWare utility by KDS Software which allows a user
      to take over control of a workstation remotely; LHR is the program
      run on the slave workstation
SeeAlso: AX=7AC8h,AX=7AC9h,AX=7ACFh
--------N-2F7AC2-----------------------------
INT 2F - LAN HiJack - LHR - SYNCHRONIZE SHIFT STATES???
    AX = 7AC2h
Note:    sets BIOS keyboard status byte to an internal variable
SeeAlso: AX=7AC3h,AX=7ACFh
--------N-2F7AC3-----------------------------
INT 2F - LAN HiJack - LHR - CLEAR ??? FLAG
    AX = 7AC3h
SeeAlso: AX=7AC2h,AX=7ACFh
--------N-2F7AC8-----------------------------
INT 2F - LAN HiJack - LHR - ENABLE FUNCTIONS
    AX = 7AC8h
    BL = function(s) to enable (see below)
SeeAlso: AX=7AC1h,AX=7AC9h,AX=7ACFh

Bitfields for function(s) to enable/disable:
 bit 0    ???
 bit 1    remote keyboard enabled
 bit 2    support remote's mouse
 bits 3-7 unused
--------N-2F7AC9-----------------------------
INT 2F - LAN HiJack - LHR - DISABLE FUNCTIONS
    AX = 7AC9h
    BL = function(s) to disable (see AX=7AC8h)
SeeAlso: AX=7AC1h,AX=7AC8h
--------N-2F7ACA-----------------------------
INT 2F - LAN HiJack - LHJ - ???
    AX = 7ACAh
    BL = ???
Return: ???
Program: LAN HiJack is a NetWare utility by KDS Software which allows a user
      to take over control of a workstation remotely; LHJ is the program
      run on the controlling workstation
--------N-2F7ACB-----------------------------
INT 2F - LAN HiJack - LHJ - ???
    AX = 7ACBh
    BX = ???
Return: ???
Note:    this function appears to be related to the keyboard
SeeAlso: AX=7ACCh
--------N-2F7ACC-----------------------------
INT 2F - LAN HiJack - LHJ - ???
    AX = 7ACCh
    BX = ???
Return: ???
Note:    this function appears to be related to the mouse
SeeAlso: AX=7ACBh
--------N-2F7ACFBX0000-----------------------
INT 2F - LAN HiJack - LHR - INSTALLATION CHECK
    AX = 7ACFh
    BX = 0000h
Return: BX = segment of resident code if installed
Program: LAN HiJack is a NetWare utility by KDS Software which allows a user
      to take over control of a workstation remotely; LHR is the program
      run on the slave workstation
--------N-2F7AF0-----------------------------
INT 2F - Novell NetWare - DOSNP.EXE v1.30G - INSTALLATION CHECK
    AX = 7AF0h
Return: AL = FFh if present
        ES = 7AF0h
        CX = PSP segment of resident code
--------N-2F7AF1-----------------------------
INT 2F - Novell NetWare - Access Server Driver - INSTALLATION CHECK
    AX = 7AF1h
    BL = sequence number (01h first driver, 02h second, 00h no driver)
Return: AX <> 7AF1h if present
        BH = total number of drivers
        ---if BL nonzero on entry---
        AL = number of ports provided by specified driver
        ES:DI -> driver entry point (see below)
        ES:DX -> ID string

Call driver entry point with:
   AH    function
   01h initialize port
    AL = port number (00h-0Fh)
    ES:BX -> configuration parameter block (see below)
    interrupts disabled
    Return: CF clear if successful
        CF set on error
   02h get port status
    AL = port number (00h-0Fh)
    interrupts disabled
    Return: CF clear if successful
            BL = transmitter status (see below)
            BH = receiver status (see below)
            DL = external status signals (see below)
        CF set on error
        interrupts disabled
   03h get input from port
    AL = port number (00h-0Fh)
    CX = size of data buffer
    ES:BX -> buffer for data
    interrupts disabled
    Return: CF clear if successful
        CF set on error
        interrupts disabled
        CX = number of bytes read
    Note:    the driver will add a NUL to the buffer when a break
          signal is detected
   04h send output data to port
    AL = port number (00h-0Fh)
    CX = number of bytes to send
    ES:BX -> buffer containing data
    interrupts disabled
    Return: CF clear if successful
        CF set on error
        interrupts disabled
        CX = number of bytes actually written
   05h get I/O character counts
    AL = port number (00h-0Fh)
    interrupts disabled
    Return: CF clear if successful
            BX = number of bytes pending transmission
            CX = number of bytes available for reading
        CF set on error
        interrupts disabled
   06h control XON/XOFF
    AL = port number (00h-0Fh)
    DL = new state
        (00h software flow control disabled, else enabled)
    interrupts disabled
    Return: CF clear if successful
        CF set on error
        interrupts disabled
   07h get error counts and statistics
    AL = port number (00h-0Fh)
    ES:BX -> buffer for statistics (see below)
    interrupts disabled
    Return: CF clear if successful
            ES:BX buffer filled
        CF set on error
        interrupts disabled
   08h general request
    AL = port number (00h-0Fh)
    DX = requested operations
        bit 0: flush transmit buffers
        bit 1: flush receive buffers
        bit 4: define XON/XOFF characters
    ES:BX -> XON/XOFF characters (see below) if DX bit 4 set
    interrupts disabled
    Return: CF clear if successful
        CF set on error
        interrupts disabled
   09h deadman timer management
    AL = port number (00h-0Fh)
    BX = next time interval in seconds (0000h to disable timer)
    interrupts disabled
    Return: CF clear
        interrupts disabled
   0Ah get buffer sizes
    AL = port number (00h-0Fh)
    interrupts disabled
    Return: CF clear if successful
           BX = size of transmit buffer
           CX = size of receive buffer
        CF set on error
        interrupts disabled

Values for transmitter status:
 00h    uninitialized
 01h    ready, not transmitting
 02h    transmitting
 03h    XOFF received
 04h    transmitting, buffer full
 05h    XOFF received and buffer full

Values for receiver status:
 00h    uninitialized
 01h    ready
 02h    receive buffer full, data may have been lost

Bitfields for external status signals:
 bits 7,6 undefined
 bit 5    CTS active
 bit 4    DSR active
 bit 3    DCD active
 bits 2,1 undefined
 bit 0    ring indicator

Format of configuration parameter block:
Offset    Size    Description
 00h    BYTE    receive baud rate index
        00h 50 bps, 01h 75 bps, 02h 110 bps, 03h 134.5 bps,
        04h 150 bps, 05h 300 bps, 06h 600 bps, 07h 1200 bps,
        08h 1800 bps, 09h 2000 bps, 0Ah 2400 bps, 0Bh 3600 bps,
        0Ch 4800 bps, 0Dh 7200 bps, 0Eh 9600 bps, 0Fh 19200 bps,
        10h 38400 bps, 11h 57600 bps, 12h 115200 bps
 01h    BYTE    receive bits per character (0=5 bits..3=8 bits)
 02h    BYTE    receive stop bits
 03h    BYTE    receive parity
        00h none, 01h odd, 02h even, 03h mark, 04h space
 04h    BYTE    transmit baud rate index (same as receive baud rate)
 05h    BYTE    transmit bits per character (0=5 bits..3=8 bits)
 06h    BYTE    transmit stop bits
 07h    BYTE    transmit parity (same as receive parity)
 08h    BYTE    DTR state (00h off, 01h on)
 09h    BYTE    RTS state (00h off, 01h on)
 0Ah    BYTE    flow control
        00h none, 01h XON/XOFF, 02h RTS/CTS, 03h both
 0Bh    BYTE    break control (00h off, 01h on)

Format of statistics:
Offset    Size    Description
 00h    BYTE    port number
 01h    BYTE    external status signals (see above)
 02h    BYTE    transmitter status (see above)
 03h    BYTE    receiver status (see above)
 04h    DWORD    number of characters received
 08h    DWORD    number of characters transmitted
 0Ch    WORD    input parity errors
 0Eh    WORD    input framing errors
 10h    WORD    lost characters due to hardware overrun
 12h    WORD    lost characters due to data buffer overrun
Note:    the counts are not allowed to wrap around; once a count reaches FFFFh
      or FFFFFFFFh, it is no longer incremented

Format of XON/XOFF characters:
Offset    Size    Description
 00h    BYTE    04h (number of bytes following)
 01h    BYTE    transmit XON character
 02h    BYTE    transmit XOFF character
 03h    BYTE    receive XON character
 04h    BYTE    receive XOFF character
--------N-2F7AFE-----------------------------
INT 2F - Novell NetWare - DOSNP.EXE - INSTALLATION CHECK
    AX = 7AFEh
Return: AL = FFh if present
        ES = (data???) segment of DOSNP
Program: DOSNP.EXE provides "named pipes" support for DOS workstations running
       NetWare
Note:    the NetWare shell calls this function and refuses to load if DOSNP is
      present
SeeAlso: AX=7A90h
--------N-2F7AFFBX0000-----------------------
INT 2F - Novell NetWare - TBMI v1.1+ - INSTALLATION CHECK???
    AX = 7AFFh
    BX = 0000h
    CX = 4E65h ("Ne")
    DX = 7457h ("tW")
    ES:DI -> IPX/SPX special handler (XMS/EMS ???)
Return: AL = FFh if installed
        CX = configured sockets (14h)
        DS:SI -> data table ???
        ES:DI -> IPX far call handler
Notes:    for IPX/SPX this call reportedly returns DS:SI pointing to the table
      of pointers to service events queue head and tail
    this function is also supported by IPXODI
SeeAlso: AX=7AFFh/BX=0001h
--------N-2F7AFFBX0001-----------------------
INT 2F - Novell NetWare - TBMI v1.1+, shell v3.01d - INSTALLATION CHECK???
    AX = 7AFFh
    BX = 0001h
    CX = 4E65h ("Ne")
    DX = 7457h ("tW")
Return: AL = FFh if installed
        CX = ???  (8000h)
        SI = ??? (or -> ???) (0002h)
        ES:DI -> IPX far call handler
        ES:DX -> 6-byte data area ???
Note:    this function is also supported by IPXODI
SeeAlso: AX=7AFFh/BX=0000h
--------d-2F7F00-----------------------------
INT 2F - Jim Harper's CD-ROM redirector SCSI driver - INSTALLATION CHECK
    AX = 7F00h
Return: AL = FFh if installed
SeeAlso: AX=7F01h,AX=7F02h,AX=7F03h
--------d-2F7F01-----------------------------
INT 2F - Jim Harper's CD-ROM redirector SCSI driver - DO COMMAND
    AX = 7F01h
    DS:DX -> command record (see below)
Return: AL = status
        00h successful
        else error code
SeeAlso: AX=7F00h,AX=7F02h,INT 11/AH=FFh"SDLP",INT 21/AX=4402h"ASPI"
SeeAlso: INT 4F/AX=8100h

Format of command record:
Offset    Size    Description
 00h    BYTE    ID
 01h 10 BYTEs    CDB (Command Descriptor Block) for operation
 0Bh    WORD    segment of buffer
 0Dh    WORD    offset of buffer
 0Fh    BYTE    status
 10h    BYTE    sense
 12h    WORD    count
--------d-2F7F02-----------------------------
INT 2F - Jim Harper's CD-ROM redirector SCSI driver - DO RESET
    AX = 7F02h
SeeAlso: AX=7F00h,AX=7F01h
--------d-2F7F03-----------------------------
INT 2F - Jim Harper's CD-ROM redirector SCSI driver - UNINSTALL
    AX = 7F03h
Return: AL = status
        00h successful
        01h unable to uninstall
SeeAlso: AX=7F00h
----------2F7F24-----------------------------
INT 2F - Multiplex - ???
    AX = 7F24h
    ???
Return: ???
Note:    called by PC/370, an IBM 370 emulator by Donald S. Higgins
----------2F7F26-----------------------------
INT 2F - Multiplex - ???
    AX = 7F26h
    ???
Return: ???
Note:    called by PC/370, an IBM 370 emulator by Donald S. Higgins
--------!------------------------------------