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

Text File | 1997-01-12 | 342KB | 9,178 lines

Interrupt List, part 9 of 16
Copyright (c) 1989,1990,1991,1992,1993,1994,1995,1996,1997 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 with CF set or (MS-DOS 1,DR DOS) RETF 2 with CF set
        DOS will abort program with errorlevel 0
    else (RETF/RETF 2 with CF clear or IRET with CF ignored)
        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)
    MS-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
    MS-DOS 2.1+ ignores the returned CF if SP is the same on return as it
      was when DOS called INT 23, so RETF 2 will not terminate the program
    Novell DOS 7 always pops a word if CF is set on return, so one should
      not return with RETF 2 and CF set or IRET with the stored flags' CF
      set
    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 C - DOS 1+ - CRITICAL ERROR HANDLER
Notes:    invoked when a critical (usually hardware) error is encountered by DOS
      (see #1879); should never be called directly
    when DOS terminates a program, it copies the previous value of the
      INT 24 vector out of the PSP (see #0725) and into the interrupt
      vector table
SeeAlso: INT 21/AH=95h

(Table 1879)
Values critical error handler is called with:
    AH = type and processing flags (see #1880)
    AL = drive number if AH bit 7 clear
    BP:SI -> device driver header (see #0987 at INT 21/AH=52h)
        (BP:[SI+4] bit 15 set if character device)
    DI low byte contains error code if AH bit 7 set (see #1881)
    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
Return: AL = action code (see #1882)
    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 3.0+) if a critical error occurs inside the critical error
      handler, the DOS call is automatically failed (AL set to 03h and
      the INT 24 call skipped)

Bitfields for critical error type and processing flags:
Bit(s)    Description    (Table 1880)
 7    clear = disk I/O error
    set   = -- if block device, bad FAT image in memory
        -- if char device, error code in DI
 6    unused
 5    Ignore allowed (DOS 3.0+)
 4    Retry allowed (DOS 3.0+)
 3    Fail allowed (DOS 3.0+)
 2-1    disk area of error
    00 = DOS area    01 = FAT
    10 = root dir    11 = data area
 0    set if write, clear if read

(Table 1881)
Values for critical error code:
 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 3.0+) sharing violation
 0Eh    (DOS 3.0+) lock violation
 0Fh    invalid disk change
 10h    (DOS 3.0+) FCB unavailable
 11h    (DOS 3.0+) sharing buffer overflow
 12h    (DOS 4.0+) code page mismatch
 13h    (DOS 4.0+) out of input
 14h    (DOS 4.0+) insufficient disk space

(Table 1882)
Values for critical error handler action code:
 00h    ignore error and continue processing request
 01h    retry operation
 02h    terminate program as though INT 21/AH=4Ch called (INT 20h for DOS 1.x)
 03h    fail system call in progress (DOS 3+)
--------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 (not FFFFh)
    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 (see #1883)
        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
    Novell DOS 7 decides whether the old-style or new-style (>32M) version
      of INT 25 must be used solely on the basis of the partition's size,
      thus forcing use of the new-style call even for data in the first
      32M of the partition
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,INT 21/AX=7305h

(Table 1883)
Values for disk I/O 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
--------D-25----CXFFFF-----------------------
INT 25 - DOS 3.31+ - ABSOLUTE DISK READ (32M-2047M hard-disk partition)
    CX = FFFFh
    AL = drive number (0=A, 1=B, etc)
    DS:BX -> disk read packet (see #1884)
Return: CF clear if successful
    CF set on error
        AH = status (see #1883)
        AL = error code (same as passed to INT 24 in DI)
    may destroy all other registers except segment registers
Notes:    partition is potentially >32M (and requires this form of the call) if
      bit 1 of the device attribute word in the device driver is set
    original flags are left on stack, and must be removed by caller
    this call bypasses the DOS filesystem
    for FAT32 drives (which may be up to 2TB in size), use INT 21/AX=7305h
SeeAlso: INT 13/AH=02h,INT 25,INT 26/CX=FFFFh,INT 21/AX=7305h

Format of disk read packet:
Offset    Size    Description    (Table 1884)
 00h    DWORD    sector number
 04h    WORD    number of sectors to read
 06h    DWORD    transfer address
SeeAlso: #1888
--------k-25CDCD-----------------------------
INT 25 - Stacker - GET DEVICE DRIVER ADDRESS
    AX = CDCDh
    DS:BX -> buffer for address (see #1885)
    CX = 0001h
    DX = 0000h
Return: AX = CDCDh if Stacker installed
        DS:BX buffer filled
Note:    not supported by Stacker Anywhere; to obtain the Stacker device
      driver address and to detect drives controlled by all versions
      of Stacker, INT 21/AX=4404h"Stacker" or lookup via the CDS and DPB
      should be preferred (see INT 21/AH=52h)
    Stacker Anywhere does not link its built-in device driver into
      the standard device driver chain, but it can be found via CDS/DPB
SeeAlso: INT 21/AX=4404h"Stacker"

Format of Stacker v2+ driver address buffer:
Offset    Size    Description    (Table 1885)
 00h    WORD    signature CDCDh
 02h    WORD    ??? 0001h
 04h    DWORD    pointer to Stacker signature at device driver offset 1Ah
          (see #1886)

Format of Stacker v2+ device driver:
Offset    Size    Description    (Table 1886)
 00h    DWORD    pointer to next driver, offset=FFFFh if last driver
        FFFFh:FFFFh for Stacker Anywhere
 04h    WORD    device attributes (see #0988,#0989)
 06h    WORD    device strategy entry point
 08h    WORD    device interrupt entry point
 0Ah    BYTE    number of subunits (drives) supported by driver
        0 for Stacker Anywhere
 0Bh  7 BYTEs    signature "STAC-CD" for Stacker and Stacker Anywhere
 12h  7 BYTEs    ???
 19h    BYTE    always = 01h ?? (Stacker Anywhere points here)
 1Ah    WORD    signature A55Ah (all other Stacker versions point here)
 1Ch    WORD    Stacker version * 64h
        0C8h = 200, 012Ch = 300, 0190h = 400 (also Stacker Anywhere)
 1Eh    WORD    offset of volume-specific information offset table
        (list of WORDs, one per drive, containing offsets to various
          information)
 20h 56 BYTEs    n/a
 58h    BYTE    volume number, set after INT 21/AX=4404h, INT 21/AX=4408h
        (use to index into volume-specific info offset table,
        should be set to FFh before and tested for change after)
 59h 19 BYTEs    n/a
 6Ch  4 BYTEs    ASCII string "SWAP"
 70h 26 BYTEs    drive mapping table (one byte for each drive A: through Z:)
        (only used for drives swapped by SSWAP.COM; other drives
        compressed by Stacker can be found with the standard device
        driver header signature (see INT 21/AH=52h)
---Stacker 4, Stacker Anywhere---
 8Ah 40    BYTEs    ???
 B2h  4 BYTEs    ASCII string "SWP2"
 B6h 26 BYTEs    drive table ???
 D0h 150 BYTEs    ???
166h 60 BYTEs    LZSINFO structure (see #2087 at INT 2F/AX=4A12h)
SeeAlso: #1887,#0987 at INT 21/AH=52h

Format of Stacker boot record:
Offset    Size    Description    (Table 1887)
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    ???
SeeAlso: #1886
--------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 (not FFFFh)
    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 (see #1883)
        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
    Novell DOS 7 decides whether the old-style or new-style (>32M) version
      of INT 26 must be used solely on the basis of the partition's size,
      thus forcing use of the new-style call even for data in the first
      32M of the partition
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,INT 21/AX=7305h
--------D-26----CXFFFF-----------------------
INT 26 - DOS 3.31+ - ABSOLUTE DISK WRITE (32M-2047M hard-disk partition)
    CX = FFFFh
    AL = drive number (0=A, 1=B, etc)
    DS:BX -> disk write packet (see #1888)
Return: CF clear if successful
    CF set on error
        AH = status (see #1883)
        AL = error code (same as passed to INT 24 in DI)
    may destroy all other registers except segment registers
Notes:    partition is potentially >32M (and requires this form of the call) if
      bit 1 of the device attribute word in the 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
    for FAT32 drives (which may be up to 2TB in size), use INT 21/AX=7305h
SeeAlso: INT 13/AH=03h,INT 25/CX=FFFFh,INT 26,INT 21/AX=7305h

Format of disk write packet:
Offset    Size    Description    (Table 1888)
 00h    DWORD    sector number
 04h    WORD    number of sectors to read
 06h    DWORD    transfer address
SeeAlso: #1884
--------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 3.0+; 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
    BX may be destroyed by some versions of DOS 3.3
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"AVATAR.SYS"
--------U-29E60DCL0E-------------------------
INT 29 - ShowGFX - INSTALLATION CHECK
    AX = E60Dh
    CL = 0Eh
    DX = C0DEh
Return: DX = DEC0h
Program: ShowGFX is a PCBoard graphics driver by Solar Designer
--------N-2A00-------------------------------
INT 2A - NETWORK - INSTALLATION CHECK
    AH = 00h
Return: AH <> 00h if installed
    CF set if NetWare v2.15 NetBIOS emulator installed
Note:    supported by PC LAN Program, LAN Manager, LANtastic, NetWare, 10NET,
      etc.
SeeAlso: INT 5C"NetBIOS"
--------N-2A0000-----------------------------
INT 2A - AT&T Starlan Extended NetBIOS (var length names) - INSTALLATION CHECK
    AX = 0000h
Return: AH = DDh
SeeAlso: INT 5B"Extended NetBIOS"
--------N-2A01-------------------------------
INT 2A - NETWORK (Microsoft,LANtastic) - EXECUTE NETBIOS REQUEST,NO ERROR RETRY
    AH = 01h
    ES:BX -> NCB (see #2500 at INT 5C"NetBIOS")
Return: AL = NetBIOS error code
    AH = status
        00h no error
        01h error occurred
SeeAlso: AH=04h,AX=0500h,INT 5B"Extended NetBIOS",INT 5C"NetBIOS"
--------N-2A02-------------------------------
INT 2A - NETWORK (Microsoft) - SET NET PRINTER MODE
    AH = 02h
    ???
Return: ???
--------N-2A0300-----------------------------
INT 2A - NETWORK - 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)
    use AH=00h to determine whether the network is installed; if not,
      direct physical access is allowed
    may take some time to execute, so programs which need to check
      frequently should save the result of the first call
    this function is called by the DOS kernel on INT 25 and INT 26
    supported by PC LAN Program, LAN Manage, LANtastic, NetWare, 10NET,
      etc.
SeeAlso: INT 13/AH=02h,INT 13/AH=03h,INT 25,INT 26,INT 21/AX=5F02h
--------N-2A04-------------------------------
INT 2A - NETWORK - EXECUTE NetBIOS REQUEST
    AH = 04h
    AL = error retry
        00h automatically retry request on errors 09h, 12h, and 21h
          (see #2499 at INT 5C"NetBIOS")
        01h no retry
        02h ???
    ES:BX -> Network Control Block (see #2500 at 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
    supported by PC LAN Program, LANtastic, LAN Manager, NetWare, 10NET,
      etc.
    NetWare 2.15 NetBIOS emulator returns CF clear if successful, CF set
      on error
    PC LAN Program defines any non-zero return value in AH as an error
      indicator for subfunction 00h, and any non-zero return value in AX
      as an error indicator for subfunction 01h
SeeAlso: AH=00h,AH=01h,AX=0500h,INT 5B"Extended NetBIOS",INT 5C"NetBIOS"
--------N-2A0500-----------------------------
INT 2A - NETWORK - 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
Notes:    supported by PC LAN Program, LAN Manager, LANtastic, NetWare, 10NET,
      etc.
    the application should call this function before using any network
      resources, and maintain its own count to avoid exceeding the
      network's resource limits
SeeAlso: AH=00h,AH=01h,AH=04h,INT 5C"NetBIOS"
--------N-2A06-------------------------------
INT 2A - NETBIOS, LANtastic - NETWORK PRINT-STREAM CONTROL
    AH = 06h
    AL = function
        01h set concatenation mode
        all printer output put in one job until return to DOS prompt
        02h set truncation mode (default)
        printer open/close or BIOS/DOS output switch starts new 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-*
    supported by PC LAN Program, LANtastic, NetWare, 10NET, etc.
    LANtastic v4.x no longer supports this call
    this function sets the printer mode for all redirected printers
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-2A4147DX0000-----------------------
INT 2A U - NetSoft DOS-NET v1.20+ - INSTALLATION CHECK
    AX = 4147h ('AG')
    DX = 0000h
Return: DX = 4147h if installed
        DS:SI -> configuration data (see #1889)
Program: DOS-NET is a shareware networking package by Albert Graham
Note:    this call is supported by CLIENT.COM, SERVER.COM, ROUTER.COM, and
      NETDOS.COM
SeeAlso: INT 65/DX=4147h,INT 65/DX=4741h

Format of DOS-NET v1.20 configuration data area:
Offset    Size    Description    (Table 1889)
 00h    BYTE    ???
 01h    BYTE    interrupt number used by DOS-NET APIs
 02h    WORD    function number to place in AX for above interrupt
 04h    BYTE    minor version as two BCD digits (e.g. 20h for v1.20)
 05h    BYTE    major version number (01h for v1.20)
 06h  2 BYTEs    ???
 08h    WORD    ??? (used by ARCNET.COM)
        bit 15: ??? (set by MACTEST.COM)
 0Ah    WORD    ??? (used by NDIS.COM and ODI.COM)
 0Ch 22 BYTEs    ???
 24h    DWORD    -> ??? function (set by PROTECT.COM)
 28h 12 BYTEs    ???
 34h    DWORD    -> ??? function (set by FASTVIEW.COM)
 38h    DWORD    -> ??? function (set by FASTVIEW.COM)
 58h    DWORD    -> ??? (offsets 04h and 1Ah from value are used by NETFILES)
    ???
 7Ch    WORD    ???
 7Eh    WORD    ??? (may be high half of a DWORD at 7Ch)
    ???
 A8h    DWORD    -> ??? (used by SM.COM)
    ???
114h    WORD    ???
116h    WORD    ??? (may be high half of a DWORD at 114h)
    ???
1BDh    BYTE    ??? flags
        bit 0: ???
        bit 6: ???
    ???
1E1h    BYTE    ???
    ???
208h    WORD    ??? (used by SM.COM, MACTEST)
282h    WORD    ???
284h  2 BYTEs    ???
286h    WORD    ??? flags
        bit 0: ???
    ???
31Eh    WORD    ???
320h    WORD    ??? (used by NDIS.COM and ODI.COM)
322h  8 BYTEs    ???
32Ah    WORD    ??? (used by NDIS.COM and ODI.COM)
    ???
33Eh  4 BYTEs    ??? (used by ODI.COM)
342h  N BYTEs    ??? (used by NDIS.COM)
    ???
3CFh    BYTE    ??? flags
        bit 2: ???
3D2h    BYTE    installed-component flags
        bit 0: PROTECT installed
        bit 1: NETCACHE installed
        bit 3: SM.COM installed
        bit 7: NETDEBUG installed
3D3h    BYTE    installed-component flags
        bit 0: NETFILES installed
        bit 6: FASTVIEW installed
    ???
3FFh    BYTE    ??? (used by NDIS.COM)
400h    BYTE    ???
401h    BYTE    ??? (used by SM.COM)
402h    BYTE    ??? (used by SM.COM)
    ???
448h    BYTE    ???
449h    BYTE    ??? (used by MACTEST)
44Ah    BYTE    ??? (used by PROTECT)
44Bh    BYTE    ???
44Ch    BYTE    ???
44Dh    BYTE    ??? (used by SM.COM)
44Eh    BYTE    ??? (used by SM.COM, MACTEST)
    ???
--------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) (see #1890)
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 #1027 at 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 4.0+ to enable use of critical sections.    For DOS 4.0+, all
      words in this list point at the byte at offset 0D0Ch.
    MS Windows patches the DOS kernel's calls to INT 2A/AH=80h-81h into
      far calls to its own handler, and does not reflect the calls back
      to INT 2A unless SYSTEM.INI contains ReflectDOSInt2A=1 or
      ModifyDOSInt2A=0 in the [386Enh] section
    Novell NETX does not issue INT 2A/AH=80h and INT 2A/AH=81h calls when
      it intercepts INT 21 calls and processes them itself
SeeAlso: AH=81h,AH=82h,AX=8700h,INT 21/AX=5D06h,INT 21/AX=5D0Bh

(Table 1890)
Values for DOS critical section number:
 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, CORELCDX
 0Fh    IBM PC LAN server (while intercepting INT 10/AH=06h,07h,0Eh)
--------D-2A81-------------------------------
INT 2A CU - NETWORK - END DOS CRITICAL SECTION
    AH = 81h
    AL = critical section number (00h-0Fh) (see #1890)
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
    MS Windows patches the DOS kernel's calls to INT 2A/AH=80h-81h into
      far calls to its own handler, and does not reflect the calls back
      to INT 2A unless SYSTEM.INI contains ReflectDOSInt2A=1 or
      ModifyDOSInt2A=0 in the [386Enh] 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 MS-DOS versions <= 6.22, and points at an
      IRET instruction
--------D-2B---------------------------------
INT 2B - IBM ROM-DOS v4.0 - ???
    AH = function
        00h ??? (modifies data in IBMBIO.COM)
        01h internal operations
        02h ???
        AL = index (00h-0Ch)
        Return: AX = ??? or (CMOS 2Dh and CMOS 2Eh)
        03h get ??? data
        Return: AX = (CMOS 2Dh and CMOS 2Eh)
            BX = FFFFh
        other does nothing
Note:    function 03h is called by ROMSHELL.COM; if BX != 0, then the ES:DI from
      INT 2F/AX=1982h points at valid data
SeeAlso: INT 2F/AX=1982h
--------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 - Cloaking - CALL PROTECTED-MODE PASSALONG CHAIN
Notes:    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.
    the cloaking host calls the passalong chain with EAX=58494E33h ('WIN3')
      when MS Windows starts up and with EAX=334E4958h ('3NIW') when
      Windows shuts down; between these two broadcasts, the additional
      Windows-only Cloaking services are available
    this function was first introduced with RM386 (RAM-MAN/386) v6.00, the
      memory manager included in Helix Software's Netroom
SeeAlso: INT 2C/AX=0009h,INT 2F/AX=4310h"Cloaking"
--------m-2C0000-----------------------------
INT 2C P - 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 #1891)
Notes:    this INT 2C interface is used by Netroom's DPMI.EXE v3.00
    to access extended memory, set the base address to the desired
      physical address plus 400000h (4M)
    this function was first introduced with RM386 (RAM-MAN/386) v6.00, the
      memory manager included in Helix Software's Netroom
SeeAlso: AX=0001h,AX=0002h,AX=0003h,AX=0004h,AX=0005h,INT 31/AH=57h,#0405

(Table 1891)
Values for Cloaking 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 - Cloaking - FREE GDT SELECTOR
    AX = 0001h
    SI = selector
Return: CF clear if successful
    CF set on error
        AX = error code (see #1891)
Note:    this function was first introduced with RM386 (RAM-MAN/386) v6.00
SeeAlso: AX=0000h,INT 2F/AX=4310h"Cloaking"
--------m-2C0002-----------------------------
INT 2C P - 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 #1891)
Note:    this function was first introduced with RM386 (RAM-MAN/386) v6.00
SeeAlso: AX=0000h,AX=0003h,AX=0004h,INT 31/AX=0007h,#0405
--------m-2C0003-----------------------------
INT 2C P - Cloaking - SET SEGMENT LIMIT
    AX = 0003h
    SI = selector
    EBX = new limit
Return: CF clear if successful
    CF set on error
        AX = error code (see #1891)
Note:    this function was first introduced with RM386 (RAM-MAN/386) v6.00
SeeAlso: AX=0000h,AX=0002h,AX=0004h,INT 31/AX=0008h
--------m-2C0004-----------------------------
INT 2C P - Cloaking - SET SEGMENT ACCESS MODE
    AX = 0004h
    SI = selector
    CL = new access mode byte (see #0406)
Return: CF clear if successful
    CF set on error
        AX = error code (see #1891)
Note:    this function was first introduced with RM386 (RAM-MAN/386) v6.00
SeeAlso: AX=0000h,AX=0002h,AX=0003h,AX=0005h,INT 31/AX=0009h
--------m-2C0005-----------------------------
INT 2C P - Cloaking - SET SEGMENT EXTENDED ACCESS MODE
    AX = 0005h
    SI = selector
    CL = new extended access mode byte (limit field ignored) (see #1892)
Return: CF clear if successful
    CF set on error
        AX = error code (see #1891)
Note:    this function was first introduced with RM386 (RAM-MAN/386) v6.00
SeeAlso: AX=0000h,AX=0002h,AX=0003h,AX=0004h,INT 31/AX=0009h

Bitfields for extended access mode byte:
Bit(s)    Description    (Table 1892)
 7    4K granularity instead of byte granularity
 6    32-bit code segment
 5    reserved (0)
 4    segment available to system
SeeAlso: #0407
--------m-2C0006-----------------------------
INT 2C P - Cloaking - GET PROTECTED-MODE INTERRUPT VECTOR
    AX = 0006h
    CL = vector (00h-7Fh)
Return: CF clear
    DX:EBX -> current interrupt handler
Note:    this function was first introduced with RM386 (RAM-MAN/386) v6.00
SeeAlso: AX=0007h,INT 31/AX=0204h
--------m-2C0007-----------------------------
INT 2C P - Cloaking - SET PROTECTED-MODE INTERRUPT VECTOR
    AX = 0007h
    CL = vector (00h-7Fh)
    DX:EBX -> interrupt handler
Return: CF clear
Notes:    this function was first introduced with RM386 (RAM-MAN/386) v6.00
    the IDT entry's type remains unchanged
SeeAlso: AX=0006h,INT 31/AX=0205h
--------m-2C0008-----------------------------
INT 2C P - Cloaking - GET PASSALONG ADDRESS
    AX = 0008h
Return: CF clear
    DX:EBX = current passalong address
Note:    this function was first introduced with RM386 (RAM-MAN/386) v6.00
SeeAlso: AX=0009h,AX=002Ch,INT 2F/AX=4310h"Cloaking"
--------m-2C0009-----------------------------
INT 2C P - Cloaking - SET PASSALONG ADDRESS
    AX = 0009h
    DX:EBX = new value for passalong address (see #1893)
Return: CF clear
Notes:    when an INT 2C instruction is executed in V86 mode, the Cloaking host
      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).  The final handler should return with CF clear to cause
      the interrupt to be reflected back to V86 mode if none of the
      passalong handlers is triggered
    this function was first introduced with RM386 (RAM-MAN/386) v6.00
SeeAlso: AX=0008h,AX=002Dh,INT 2C"PASSALONG CHAIN"

(Table 1893)
Values Cloaking passalong address is called with:
    EAX = CS:IP of byte following INT 2C instruction invoking passalong
    SS:EBX -> caller registers (see #1894)
    CF clear
    others undefined
Return: CF clear: pass along to V86-mode INT 2C handler
    CF set: return immediately to V86 mode

Format of Cloaking caller registers:
Offset    Size    Description    (Table 1894)
 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 - 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 #1891)
Note:    this function was first introduced with RM386 (RAM-MAN/386) v6.00, the
      memory manager included in Helix Software's Netroom
SeeAlso: AX=0000h,AX=0002h,AX=000Bh
--------m-2C000B-----------------------------
INT 2C P - 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 #1891)
Note:    this function was first introduced with RM386 (RAM-MAN/386) v6.00
SeeAlso: AX=000Ah,INT 2F/AX=4310h"Cloaking"
--------m-2C---------------------------------
INT 2C P - RM386 v6.00 - CLOAKING - RESERVED FOR CLOAKED BIOS USE UNDER WINDOWS
    AX = function (000Ch-001Fh)
--------m-2C000F-----------------------------
INT 2C P - Cloaking v1.01 - "Simulate_Shell_Event"
    AX = 000Fh
    ECX = event code (see #1895)
    DX = subfunction for event
    EDX high word = boost value (see #1896)
    SI:EDI -> completion procedure
Return: CF clear if successful (event scheduled)
    CF set on error
Note:    this function is only available while MS Windows is running
SeeAlso: AX=0011h,AX=0012h,INT 2F/AX=1605h,INT 2F/AX=4310h"Cloaking"

(Table 1895)
Values for Cloaking shell event code:
 0414h    Hot key event
    subevent 0000h: Alt-Space
    subevent 0001h: Alt-Enter
    subevent 0002h: Dir-VM
 0415h    Switch context
    subevent 0000h for DOS VM context, nonzero for System VM context
 0416h    Clipboard event
 0417h    Termination event
    subevent 0000h for normal termination, nonzero for error
 0418h    Display message
    subevent 0000h for normal message, nonzero for system model ASAP
 0419h    Crash
 041Ah    Paste complete
    subevent 0000h: normal
    subevent 0001h: cancelled by user
    subevent 0002h: cancelled
 041Bh    Contention event
 041Ch    Screen switch
    subevent 0000h: forward
    subevent 0001h: back
 041Dh    Filesystem change
 041Eh    Check Focus
 041Fh    Panic

Bitfields for boost value:
Bit(s)    Description    (Table 1896)
 0    boost system VM until focus changes
 1    boost system VM on Switcher screen
 2    boost system VM until response
 3    boost system VM during clipboard activity
 4    boost system VM during print screen
 5    boost system VM during update
--------m-2C0011-----------------------------
INT 2C P - Cloaking v1.01 - "Switch_VMs_and_Call_back"
    AX = 0011h
    EBX = handle of VM to be made active
    SI:EDI -> 32-bit FAR completion procedure
Return: CF clear if successful (scheduled)
    CF set on error
Notes:    this function is only available while MS Windows is running
    the completion procedure is called with CF clear if the specified
      VM has been made active, or with CF set on error
SeeAlso: AX=000Fh,AX=0012h
--------m-2C0012-----------------------------
INT 2C P - Cloaking v1.01 - "Query_Current_VM"
    AX = 0012h
Return: CF clear
    EBX = handle of active VM
    ESI = handle of system VM
    ECX = VM status flags (see #1897)
    EDX = shell flags (see #1898)
Note:    this function is only available while MS Windows is running in enhanced
      mode
SeeAlso: AX=000Fh,AX=0011h,AX=0013h

Bitfields for VM status flags:
Bit(s)    Description    (Table 1897)
 0    in exclusive mode
 1    runs in background
 2    being created
 3    suspended
 4    not executable
 5    executing in protected mode
 6    contains PM application
 7    32-bit PM application
 8    called from VxD
 9    high priority background
 10    blocked on semaphore
 11    awakening
 12    has pageable V86
 13    has locked V86
 14    is scheduled
 15    idle
 16    closing

Bitfields for shell flags:
Bit(s)    Description    (Table 1898)
 2    windowed
 5    Alt-Tab reserved
 6    Alt-Esc reserved
 7    Alt-Space reserved
 8    Alt-PrtSc reserved
 9    Alt-Enter reserved
 10    Alt-PrtSc reserved
 11    PrtSc reserved
 12    polling enabled
 13    no HMA
 14    has shortcut key
 15    locked EMS handles
 16    locked XMS handles
 17    fast paste enabled
 18    locked V86 memory
 30    close-on-exit enabled
--------m-2C0013-----------------------------
INT 2C P - Cloaking v1.01 - "Issue_System_Modal_Message"
    AX = 0013h
    EDX = message box flags (see #1899)
    DS:ECX -> ASCIZ message text
    DS:EDI -> ASCIZ caption
Return: CF clear
    EAX = response code
Note:    this function is only available while MS Windows is running in enhanced
      mode
SeeAlso: AX=000Fh,AX=0012h

Bitfields for message box flags:
Bit(s)    Description    (Table 1899)
 3-0    response codes (see #1900)
 7-4    icon codes
    1 = Warning hand
    2 = exclamation mark
    4 = asterisk
 9-8    default response (0 = first button, 1 = second, 2 = third)
 12    message is system model
 15    don't change focus
 29    hang with interrupts enabled
 30    do not window
 31    execute ASAP

(Table 1900)
Values for response codes:
 00h    OK
 01h    OK, Cancel
 02h    Abort, Retry, Ignore
 03h    Yes, No, Cancel
 04h    Yes, No
 05h    Retry, Cancel
--------m-2C001D-----------------------------
INT 2C P - Cloaking v1.01 - GET INT 2C API HANDLER ENTRY POINT
    AX = 001Dh
Return: CF clear
    DX:EBX = selector:offset of Cloaking host INT 2C handler
Desc:    get the Cloaking host's entry point to bypass any other programs
      which may have hooked INT 2C in protected mode
Note:    the returned entry point must be called with a simulated INT, i.e.
      a PUSHD must precede the far call to the handler
SeeAlso: INT 2F/AX=4310h"Cloaking"
--------m-2C001E-----------------------------
INT 2C P - Cloaking v1.01 - CLEAR CRITICAL SECTION
    AX = 001Eh
Return: CF clear
Desc:    allow MS Windows to switch to another VM after having prevented it
      by invoking a critical section
SeeAlso: AX=001Fh,INT 15/AX=101Ch,INT 2F/AX=1682h
--------m-2C001F-----------------------------
INT 2C P - Cloaking v1.01 - SET CRITICAL SECTION
    AX = 001Fh
Return: CF clear
Desc:    prevent MS Windows from switching to another VM
SeeAlso: AX=001Eh,INT 15/AX=101Bh,INT 2F/AX=1681h
--------m-2C0020-----------------------------
INT 2C P - Cloaking - GET SIZE OF PROTECTED-MODE STATE
    AX = 0020h
Return: EAX = number of bytes required for storing state
Note:    this function was first introduced with RM386 (RAM-MAN/386) v6.00
SeeAlso: AX=0021h,AX=0022h
--------m-2C0021-----------------------------
INT 2C P - Cloaking - SAVE PROTECTED-MODE STATE
    AX = 0021h
    ES:EDI -> buffer for protected-mode state
Return: CF clear
    buffer filled
Note:    this function was first introduced with RM386 (RAM-MAN/386) v6.00
SeeAlso: AX=0020h,AX=0022h
--------m-2C0022-----------------------------
INT 2C P - 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)
Note:    this function was first introduced with RM386 (RAM-MAN/386) v6.00
SeeAlso: AX=0020h,AX=0021h
--------m-2C0023-----------------------------
INT 2C P - Cloaking - ISSUE PROTECTED-MODE XMS CALL
    AX = 0023h
Notes:    not currently implemented--NOP in RM386 v6.00
    this function was first introduced with RM386 (RAM-MAN/386) v6.00
--------m-2C0024-----------------------------
INT 2C P - Cloaking - SET V86-MODE STACK
    AX = 0024h
    DX:EBX = new value for V86-mode SS:ESP
Return: nothing
Note:    this function was first introduced with RM386 (RAM-MAN/386) v6.00
--------m-2C0025-----------------------------
INT 2C P - Cloaking - CALL V86-MODE PROCEDURE
    AX = 0025h
    DS:EBX -> client register structure (see #1894)
Return: CF clear if successful
        client register structure updated
    CF set if no more nested procedure call space available
Notes:    this call uses the V86-mode stack supplied in the client structure, and
      calls the routine specified by CS:IP in the client structure
    this function was first introduced with RM386 (RAM-MAN/386) v6.00
SeeAlso: AX=0026h,AX=0027h,INT 31/AX=0301h
--------m-2C0026-----------------------------
INT 2C P - Cloaking - CALL V86-MODE INTERRUPT HANDLER
    AX = 0026h
    DS:EBX -> client register structure (see #1894)
    CX = interrupt number
Return: CF clear if successful
        client register structure updated
    CF set if no more nested procedure call space available
Notes:    this call uses the V86-mode stack supplied in the client structure
    this function was first introduced with RM386 (RAM-MAN/386) v6.00
SeeAlso: AX=0025h,AX=0027h,INT 31/AX=0300h
--------m-2C0027-----------------------------
INT 2C P - Cloaking - CHAIN TO V86-MODE INTERRUPT HANDLER
    AX = 0027h
    DS:EBX -> client register structure (see #1894)
Return: CF clear if successful
        client register structure updated
    CF set if no more nested procedure call space available
Notes:    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
    this function was first introduced with RM386 (RAM-MAN/386) v6.00
SeeAlso: AX=0025h,AX=0026h
--------m-2C0028-----------------------------
INT 2C P - Cloaking - GET ESP0 FROM TSS
    AX = 0028h
Return: CF clear
    EAX = TSS's ESP0
Note:    this function was first introduced with RM386 (RAM-MAN/386) v6.00, the
      memory manager included in Helix Software's Netroom
--------m-2C0029-----------------------------
INT 2C P - 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
Note:    this function was first introduced with RM386 (RAM-MAN/386) v6.00
--------m-2C002A-----------------------------
INT 2C P - Cloaking - SET 8259 IRQ BASE VECTORS
    AX = 002Ah
    BL = base vector of master interrupt controller
    CL = base vector of slave interrupt controller
Notes:    this call merely informs RM386 that the caller has changed the
      interrupt mappings
    this function was first introduced with RM386 (RAM-MAN/386) v6.00
SeeAlso: INT 67/AX=DE0Bh
--------m-2C002BCH81-------------------------
INT 2C P - 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
Notes:    these functions are equivalent to the INT 4B/AX=81xxh subfunctions
      with the same numbers
    this function was first introduced with RM386 (RAM-MAN/386) v6.00
SeeAlso: INT 4B/AX=8102h,INT 4B/AX=810Ch
--------m-2C002C-----------------------------
INT 2C P - Cloaking - GET PORT-TRAPPING PASSALONG
    AX = 002Ch
Return: CF clear
    DX:EBX = current I/O trapping passalong address
Note:    this function was first introduced with RM386 (RAM-MAN/386) v6.00
SeeAlso: AX=0008h,AX=002Dh
--------m-2C002D-----------------------------
INT 2C P - Cloaking - SET PORT-TRAPPING PASSALONG
    AX = 002Dh
    DX:EBX = new I/O trapping passalong address (see #1901)
Return: CF clear
Notes:    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)
    this function was first introduced with RM386 (RAM-MAN/386) v6.00
SeeAlso: AX=0009h,AX=002Ch,INT 67/AX=5DEAh

(Table 1901)
Values Cloaking port-trapping passalong address is called with:
    EAX = CS:IP of faulting instruction (unless executing in protected-mode
        ring 3)
    SS:EBX -> caller register structure (see #1894)
        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 - 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)
Note:    this function was first introduced with RM386 (RAM-MAN/386) v6.00
SeeAlso: AX=002Fh,AX=0030h
--------m-2C002F-----------------------------
INT 2C PU - 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)
Note:    this function was first introduced with RM386 (RAM-MAN/386) v6.00
SeeAlso: AX=002Eh,AX=0030h
--------m-2C0030-----------------------------
INT 2C PU - 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)
Note:    this function was first introduced with RM386 (RAM-MAN/386) v6.00
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
--------m-2C0031-----------------------------
INT 2C P - Cloaking v1.01 - ALLOCATE V86 CALLBACK
    AX = 0031h
    DX:EBX = CS:EIP of protected-mode routine to be invoked by callback
Return: CF clear if successful
        EBX = CS:IP of V86-mode callback handler
    CF set on error
SeeAlso: AX=0032h
--------m-2C0032-----------------------------
INT 2C P - Cloaking v1.01 - FREE V86 CALLBACK
    AX = 0032h
    EBX = CS:IP of V86-mode callback handler
Return: CF clear if successful
    CF set on error
        AX = error code
        0005h invalid callback address
        0006h callback already free
SeeAlso: AX=0032h
--------m-2C0033-----------------------------
INT 2C P - Cloaking v1.01 - REGISTER CLOAKING CLIENT
    AX = 0033h
    DS:EDX -> client registration structure (see #1902)
Return: CF clear if successful
    CF set on error (linked list corrupt)
SeeAlso: AX=0034h,#2058 at INT 2F/AX=4310h"Cloaking"

Format of client registration structure:
Offset    Size    Description    (Table 1902)
 00h    PWORD    link to next structure
 06h    PWORD    link to previous structure
 0Ch  2 BYTEs    client version (major, minor)
 0Eh 20 BYTEs    client name
 22h    DWORD    physical address of client start
 26h    DWORD    client's total size in bytes
Note:    the link area should not be modified once the structure has been
      used for the registration call
--------m-2C0034-----------------------------
INT 2C P - Cloaking v1.01 - UNREGISTER CLOAKING CLIENT
    AX = 0034h
    DS:EDX -> client registration structure (see #1902)
Return: CF clear if successful
    CF set on error (linked list corrupt)
Note:    the client must unregister before freeing the XMS block containing
      its registration structure(s)
SeeAlso: AX=0033h,#2058 at INT 2F/AX=4310h"Cloaking"
--------D-2D---------------------------------
INT 2D - DOS 2+ - RESERVED
Note:    this vector is not used in DOS versions <= 6.00, and points at an IRET
BUG:    RM386 v6.00-6.02 (as distributed with Helix's Netroom v3.x) contains
      a stack bug in its protected-mode INT 2D handler which causes a crash
      when INT 2D is invoked from V86 mode
--------t-2D---------------------------------
INT 2D - ALTERNATE MULTIPLEX INTERRUPT SPECIFICATION (AMIS) [v3.6]
    AH = multiplex number
    AL = function
        00h installation check
        01h get private entry point
        02h uninstall
        03h request popup
        04h determine chained interrupts
        05h get hotkey list
        06h get device-driver information
        07h-0Fh reserved for future enhancements
        Return: AL = 00h (not implemented)
        other  application-dependent
    other registers vary by function (also see individual entries below)
Return: varies by function
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 3.6 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.  TSRs which provide DOS device drivers must
      also implement function 06h.    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
    to be considered fully compliant, users of this specification must
      adhere to the IBM interrupt sharing protocol (see #1903), which will
      permit removal of TSRs in arbitrary order and interrupt handler
      reordering.  All TSRs following this specification should be
      removable unless they are loaded from CONFIG.SYS, though they need
      not keep the code for removing themselves resident; it is acceptable
      for a separate program to perform the interrupt unhooking and
      memory-freeing steps of removal.
    A sample public-domain implementation including example TSRs and
      utility programs may be found in a separate package distributed as
      AMISLnnn.ZIP (AMISL092.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 2D/AL=00h,INT 2D/AL=01h,INT 2D/AL=02h,INT 2D/AL=03h,INT 2D/AL=04h
SeeAlso: INT 2D/AL=05h,INT 2D/AL=06h,INT 2F"NOTES"

Format of interrupt sharing protocol interrupt handler entry point:
Offset    Size    Description    (Table 1903)
 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) by IBM for future expansion
Note:    when chaining to the prior handler, the interrupt handler must perform
      an indirect jump/call using the address at offset 02h in the
      ISP header.  This permits another AMIS TSR to hook itself into
      the chain at a position other than as the first handler to receive
      an interrupt.
SeeAlso: INT F1/AH=01h"Common ISDN API",INT F1/AH=06h"CAPI",#3281
--------t-2D--00-----------------------------
INT 2D - AMIS v3.0+ - INSTALLATION CHECK
    AL = 00h
    AH = multiplex number for program
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 #1904) identifying the program
          using the multiplex number
SeeAlso: INT 2D/AL=01h,INT 2D/AL=02h,INT 2D/AL=03h,INT 2D/AL=04h,INT 2D/AL=05h
SeeAlso: INT 2D/AL=06h
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

Format of AMIS signature string:
Offset    Size    Description    (Table 1904)
 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
SeeAlso: #1905

(Table 1905)
Values for AMIS 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
 'CPH1995 ' 'CDTSR   '    resident CD-Audio player
 'CPH1996 ' 'DSAPI   '
 '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)
 'DTown SD' 'DTU     '    DTown Software Development's DTown Utilities
            (see also INT 2D/AL=20h)
 'ECLIPSE ' 'PLUMP   '    Eclipse Software's printer and plotter spooler
 'GraySoft' 'GIPC    '    GraySoft's Inter-Process Communications driver
 'heathh  ' 'Monitor '
 'Helge O '        TSRs by Helge Olav Helgesen
 'J. Berry' 'RATSR   '    RemoteAccess Network Manager workstation module
 'JWB      ' 'RAMLIGHT'    James Birdsall's on-screen RAMdisk activity indicator
 'M Better' 'iHPFS   '    Marcus Better's HPFS filesystem driver for DOS
 'M. Paul ' 'FREEVER '    DOS version-faking TSR by Matthias Paul
 'Nildram ' 'ST         '    Screen Thief graphics screen grabber
 'Pino Nav' 'ALTMENU '    activate any program's menu bar by pressing Alt key
 'Pino Nav' 'Keybit  '    Pino Navato's KEYBIT Lite Italian keyboard driver v4+
 'PowrQuot' 'CAPRILOG'
 'PowrQuot' 'CAPRITSR'
 'PowrQuot' 'CAPRIWIN'
 'R-Ware  ' 'dLite   '    run-time data decompression TSR
 'Ralf B  ' 'disaXXYY'    RBdisabl -- disable key scancode XX w/ shift states YY
 'Ralf B  ' 'DUALVGA '    dual-VGA support, screen blanker, and DPMS driver
 'Ralf B  ' 'FASTMOUS'    example TSR included with sample AMIS library code
 'Ralf B  ' 'NoBreak '    disable Ctrl-@, Ctrl-C, and Ctrl-Break keys
 'Ralf B  ' 'NOLPT n '    example TSR -- turn LPTn into bit-bucket
 'Ralf B  ' 'NOTE    '    example TSR -- popup note-taker
 'Ralf B  ' 'RBclock '    RBclock -- on-screen real-time clock
 'Ralf B  ' 'RBclockE'    RBclock -- on-screen elapsed-time clock
 'Ralf B  ' 'RBdvorak'    Dvorak keyboard mapping w/ opt Esc/~, LCtrl/CapsLk swap
 'Ralf B  ' 'RBkcount'    display count of keystrokes on screen
 'Ralf B  ' 'RBkeyswp'    RBkeyswap v3.0+ -- swap Esc/~ and LCtrl/CapsLock keys
 'Ralf B  ' 'RBnoboot'    disable Ctrl-Alt-Del key combination
 'Ralf B  ' 'ShftCaps'    require Shift-CapsLock to turn on CapsLock
 'Ralf B  ' 'ShftNumL'    require Shift-NumLock to turn off NumLock
 'Ralf B  ' 'SWITCHAR'    example TSR -- add switchar() support removed from DOS5
 'Ralf B  ' 'VGABLANK'    VGA-only screen blanker
 'Ralf B  ' 'WINTAME '    yield CPU when program in Win95 DOS box is idle
 'Sally IS' 'Mdisk   '    removeable, resizeable RAMdisk
 'Sally IS' 'Scr2Tex '    screen dumper with output in (La)Tex format
 'SRT      ' 'STOPBOOT'    reboot preventer by Steve Talbot
 '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
 'WlkngOwl' 'NoiseSYS'    NOISE.SYS random-number generator
SeeAlso: #1904
--------t-2D--01-----------------------------
INT 2D - AMIS v3.0+ - GET PRIVATE ENTRY POINT
    AL = 01h
    AH = multiplex number for program
Return: AL = 00h if all API calls via INT 2D
    AL = FFh if entry point supported
        DX:BX -> entry point for bypassing interrupt chain
Note:    this function is not valid unless a program is installed on the
      specified multiplex number; use INT 2D/AL=00h to check
SeeAlso: INT 2D/AL=00h,INT 2D/AL=02h,INT 2D/AL=03h,INT 2D/AL=04h,INT 2D/AL=05h
SeeAlso: INT 2D/AL=06h
Index:    entry point;Alternate Multiplex Interrupt|entry point;AMIS
--------t-2D--02-----------------------------
INT 2D - AMIS v3.0+ - UNINSTALL
    AL = 02h
    AH = multiplex number for program
    DX:BX = return address for successful uninstall (may be    ignored by TSR)
Return: AL = status
        00h not implemented (makes TSR non-compliant with specification)
        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
        06h disabled, but can not be removed from memory
          because loaded from CONFIG.SYS
        07h safe to remove, but no resident device-driver
          uninstaller.    Caller must unlink device
          drivers from DOS device chain as well as
          unhooking interrupts and freeing memory
        BX = segment of memory block with resident code
        FFh successful
    return at DX:BX with AX destroyed if successful and TSR honors
      specific return address
Note:    this function is not valid unless a program is installed on the
      specified multiplex number; use INT 2D/AL=00h to check
SeeAlso: INT 2D/AL=00h,INT 2D/AL=01h,INT 2D/AL=03h,INT 2D/AL=04h,INT 2D/AL=05h
SeeAlso: INT 2D/AL=06h
Index:    uninstall;Alternate Multiplex Interrupt Specification|uninstall;AMIS
--------t-2D--03-----------------------------
INT 2D - AMIS v3.0+ - REQUEST POP-UP
    AL = 03h
    AH = multiplex number for program
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
Note:    this function is not valid unless a program is installed on the
      specified multiplex number; use INT 2D/AL=00h to check
SeeAlso: INT 2D/AL=00h,INT 2D/AL=01h,INT 2D/AL=02h,INT 2D/AL=04h,INT 2D/AL=05h
SeeAlso: INT 2D/AL=06h
--------t-2D--04-----------------------------
INT 2D - AMIS v3.0+ - DETERMINE CHAINED INTERRUPTS
    AL = 04h
    AH = multiplex number for program
    BL = interrupt number (except 2Dh)
Return: AL = status
        00h not implemented (makes TSR non-compliant with specification)
        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 #1906)
        FFh interrupt not hooked
Notes:    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 through 03h may not be used by AMIS v3.6-compliant
      programs; they are included here solely for compatibility with
      version 3.3, though they were probably never used in any
      implementation
    for return values 01h through 03h, 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.
    this function is not valid unless a program is installed on the
      specified multiplex number; use INT 2D/AL=00h to check
SeeAlso: INT 2D/AL=00h,INT 2D/AL=01h,INT 2D/AL=02h,INT 2D/AL=03h,INT 2D/AL=05h
SeeAlso: INT 2D/AL=06h

Format of AMIS interrupt hook list [array]:
Offset    Size    Description    (Table 1906)
 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 #1903)
SeeAlso: #1907
--------t-2D--05-----------------------------
INT 2D - AMIS v3.5+ - GET HOTKEYS
    AL = 05h
    AH = multiplex number for program
Return: AL = status
        00h not implemented
        FFh supported
        DX:BX -> hotkey list (see #1907)
Notes:    this function is not valid unless a program is installed on the
      specified multiplex number; use INT 2D/AL=00h to check
    programs which provide hotkeys are required to provide this function
      to be fully compliant with this specification
SeeAlso: INT 2D/AL=00h,INT 2D/AL=01h,INT 2D/AL=02h,INT 2D/AL=03h,INT 2D/AL=04h
SeeAlso: INT 2D/AL=06h

Format of AMIS hotkey list:
Offset    Size    Description    (Table 1907)
 00h    BYTE    type of hotkey checking (see #1908)
 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 #1909)
         03h    WORD    disallowed shift states (see #1909)
         05h    BYTE    hotkey flags (see #1910)
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.
    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
SeeAlso: #0005

Bitfields for type of AMIS hotkey checking:
Bit(s)    Description    (Table 1908)
 0    checks before chaining INT 09
 1    checks after chaining INT 09
 2    checks before chaining INT 15/AH=4Fh
 3    checks after chaining INT 15/AH=4Fh
 4    checks on INT 16/AH=00h,01h,02h
 5    checks on INT 16/AH=10h,11h,12h
 6    checks on INT 16/AH=20h,21h,22h
 7    reserved (0)
SeeAlso: #1907

Bitfields for AMIS shift states:
Bit(s)    Description    (Table 1909)
 0    right shift pressed
 1    left shift pressed
 2    either control key pressed
 3    either Alt key pressed
 4    ScrollLock active
 5    NumLock active
 6    CapsLock active
 7    either shift key pressed
 8    left control key pressed
 9    left Alt key pressed
 10    right control key pressed
 11    right Alt key pressed
 12    ScrollLock pressed
 13    NumLock pressed
 14    CapsLock pressed
 15    SysReq key pressed
Notes:    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.
    the SysReq key is often labeled SysRq
SeeAlso: #1907,#1910

Bitfields for AMIS hotkey flags:
Bit(s)    Description    (Table 1910)
 0    hotkey chained before processing
 1    hotkey chained after processing
 2    others should pass through this hotkey so that it can be monitored
 3    hotkey will not activate if other keys pressed/released before hotkey
      press is completed
 4    this key is remapped into some other key
 5    this key is conditionally chained (sometimes passed on, sometimes
      swallowed)
 6-7    reserved (0)
SeeAlso: #1907,#1909
--------t-2D--06-----------------------------
INT 2D - AMIS v3.6 - GET DEVICE-DRIVER INFORMATION
    AL = 06h
    AH = multiplex number for program
Return: AL = number of device driver headers supplied by prog.
    AH = device-driver flags (see #1911)
    DX:BX -> first device driver header (see #0987)
Program: AMIS is the Alternate Multiplex Interrupt Specification promulgated
      by Ralf Brown
Notes:    if AL=00h, AH,BX,DX are meaningless and may be destroyed
    this function is not valid unless a program is installed on the
      specified multiplex number; use INT 2D/AL=00h to check
    programs which provide device drivers are required to support this
      function to be considered fully compliant with v3.6+ of the
      specification
SeeAlso: INT 2D/AL=00h,INT 2D/AL=01h,INT 2D/AL=02h,INT 2D/AL=03h,INT 2D/AL=04h
SeeAlso: INT 2D/AL=05h

Bitfields for AMIS device-driver information flags:
Bit(s)    Description    (Table 1911)
 0    program loaded from CONFIG.SYS, and thus can not be removed from memory
    (leave clear if unable to determine)
 1    device driver headers have not been linked into DOS device chain
 2    reentrant device driver(s)
--------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 #1912)
    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 dLite parameter block:
Offset    Size    Description    (Table 1912)
 00h    BYTE    TSR flags (see #1913)
 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)

Bitfields for dLite TSR flags:
Bit(s)    Description    (Table 1913)
 0    deny FCB access
 1    dLite sleeping rather than activated
 2    always indicate original filesize when reading directory entries,
      rather than only for specified programs
 3-7    reserved
SeeAlso: #1912
--------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 #1914)
    CX = record of features loaded (see #1915)
    ES:DI -> Burnout Plus control structure (see #1916)
Program: Burnout Plus is a DOS screen saver from Cove Software
SeeAlso: INT 14/AX=AA01h,INT 2D"AMIS"
Index:    screen saver;Burnout Plus

Bitfields for Burnout Plus status:
Bit(s)    Description    (Table 1914)
 0    screen is blanked
 1    MS Windows is active (Burnout Plus deactivated)
 2-15    reserved

Bitfields for Burnout Plus features loaded/features enabled:
Bit(s)    Description    (Table 1915)
 0    mouse activity monitor
 1    passkey support
 2    password support
 3    continuous clear
 4    software blanking
 5    video activity monitor
 6    disk activity monitor
 7    activating keystroke suppression
SeeAlso: #1916

Format of Burnout Plus control structure:
Offset    Size    Description    (Table 1916)
 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 #1917)
        the bits for password, passkey, and software blanking are
          ignored and cannot be enabled or disabled externally
 0Bh    WORD    features enabled (see #1915)
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 Burnout Plus status information:
Bit(s)    Description    (Table 1917)
 0    Burnout Plus disabled
 1    force screen to blank on next clock tick
 2    restore screen if currently blanked
 3-15    reserved
Note:    1 and 2 are automatically cleared by Burnout Plus after blanking
      or restoring the screen
SeeAlso: #1916
--------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???
--------U-2D--10-----------------------------
INT 2D - DTown Utilities v1.40+ - EXTENDED API INSTALLATION CHECK
    AL = 10h
Return: AL = FFh
    BL = extended API availability (00h no, 01h API is loaded)
SeeAlso: INT 2D/AL=11h"DTown",INT 2D/AL=20h,INT 2D/AL=50h
--------s-2D--10-----------------------------
INT 2D - CDTSR - GET INTERNAL VARIABLE TABLE
    AL = 10h
    AH = AMIS multiplex number for CDTSR
Return: CX:DX -> CDTSR internal variable structure (see #1918)
Program: CDTSR is a resident audio CD player by Colin Hill
SeeAlso: INT 2D/AL=11h"CDTSR",INT 2D/AL=12h"CDTSR",INT 2D/AL=13h"CDTSR"

Format of CDTSR internal variable structure:
Offset    Size    Description    (Table 1918)
 00h    BYTE    hotkey scan code (see #0005)
 01h    BYTE    hotkey shift states
 02h    BYTE    flag: repeat
 03h    BYTE    flag: custom repeat
 04h    BYTE    flag: background polling
 05h    DWORD    (read-only) internal timing variable
 09h    DWORD    current track play position, in frames
 0Dh    DWORD    current disk play position, in frames
 11h    BYTE    number of entries in track program
 12h    BYTE    index into track program currently playing (FFh if not playing)
 13h 100 BYTEs    track program (each byte contains one track number)
 77h    BYTE    saved cursor end scan line
 78h    BYTE    saved cursor start scan line
 79h    BYTE    currently playing track
 7Ah    BYTE    CD driver media-change flag
 7Bh    WORD    video base segment during last popup
 7Dh    WORD    video page offset during last popup
 7Fh    BYTE    currently-selected track
 80h    DWORD    begin of custom repeat, in frames
 84h    DWORD    end of custom repeat, in frames
 88h    WORD    track program index of top list item
--------K-2D--10-----------------------------
INT 2D - KEYBIT Lite v5+ - GET POINTER TO STATUS BYTE
    AL = 10h
    AH = AMIS multiplex number for KEYBIT Lite
Return: DX:BX -> status byte (see #1919)
Program: KEYBIT Lite is an enhanced Italian keyboard driver by Pino Navato.
SeeAlso: INT 2D"AMIS"

Bitfields for KEYBIT Lite status byte:
Bit(s)    Description    (Table 1919)
 7    KEYBIT Lite active
 6    E-mail support active
 5-0    reserved
Notes:    E-mail support is one of the original features of KEYBIT Lite.    It is
      the automatic conversion of the 8-bits ASCII chars produced by some
      keys available on Italian keyboards to couples of 7-bits chars.
    Message editors should always enable e-mail support, they should also
      restore its original status before exiting.
    The user can change both status bits by hotkeys.
--------K-2D--10-----------------------------
INT 2D - ALTMENU - GET POINTER TO KEY CODE
    AL = 10h
    AH = AMIS multiplex number for signature 'Pino Nav' 'ALTMENU '
Return: DX:BX -> WORD key code to insert in keyboard buffer on Alt-key tap
Program: Pino Navato's freeware ALTMENU permits activating the menu bar of
      any program by pressing the Alt key alone.
Notes:    The value in the key code word will be returned in AX by a call to
      INT 16/AH=00h after the Alt key is pressed by itself
    ALTMENU may be disabled by setting the key code equal to 0000h
SeeAlso: INT 16/AH=00h,INT 2D"AMIS"
--------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"
--------U-2D--11-----------------------------
INT 2D - DTown Utilities v1.40+ - UTILITY INSTALLATION CHECK
    AL = 11h
    BL = function
        00h get number of installed utilities
        Return: BL = number of utilities
        01h get installed utilities
        DX:DI -> buffer containing one byte for each utility
        Return: DX:DI buffer filled with flags (0=no,1=yes) indicating
              whether the corresponding utility is loaded
Return: AL = FFh if supported
Note:    this function is only available if the extended API has been installed
      in the resident portion
SeeAlso: INT 2D/AL=10h"DTown",INT 2D/AL=20h
--------s-2D--11-----------------------------
INT 2D - CDTSR - REPROGRAM CDTSR
    AL = 11h
    AH = AMIS multiplex number for CDTSR
Return: nothing
Program: CDTSR is a resident audio CD player by Colin Hill
Desc:    reprograms CDTSR based on the values in the internal variable
      structure (see #1918), which may have been changed by an application
SeeAlso: INT 2D/AL=10h"CDTSR",INT 2D/AL=12h"CDTSR",INT 2D/AL=13h"CDTSR"
--------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"
--------s-2D--12-----------------------------
INT 2D - CDTSR - DISABLE POPUP
    AL = 12h
    AH = AMIS multiplex number for CDTSR
Return: nothing
SeeAlso: INT 2D/AL=10h"CDTSR",INT 2D/AL=11h"CDTSR",INT 2D/AL=13h"CDTSR"
--------U-2D--12-----------------------------
INT 2D - FREEVER - GET ORIGINAL DOS VERSION INFO
    AL = 12h
    AH = AMIS multiplex number for FREEVER
Return: AL = FFh if successful
        BH = major DOS version
        BL = minor DOS version
        CH = DOS version flag
        CL = OEM number
        DH = major DR DOS version number (FFh if unknown)
        DL = minor DR DOS version number (FFh if unknown)
Program: FREEVER is an AMIS-conformant freeware DOS version-faking TSR similar
      to SETVER for any DOS-compatible OS, written by Matthias Paul
SeeAlso: INT 2D/AL=13h"FREEVER",INT 2D/AL=14h"FREEVER",INT 2D/AL=17h"FREEVER"
--------s-2D--13-----------------------------
INT 2D - CDTSR - ENABLE POPUP
    AL = 13h
    AH = AMIS multiplex number for CDTSR
Return: nothing
Program: CDTSR is a resident audio CD player by Colin Hill
SeeAlso: INT 2D/AL=10h"CDTSR",INT 2D/AL=11h"CDTSR",INT 2D/AL=12h"CDTSR"
--------U-2D--13-----------------------------
INT 2D - FREEVER - SET VERSION NUMBERS
    AL = 13h
    AH = AMIS multiplex number for FREEVER
    BH = new major DOS version
    BL = new minor DOS version
    CH = new DOS version flag
    CL = new DOS revision number
    DH = new OEM number
SeeAlso: INT 2D/AL=12h"FREEVER",INT 2D/AL=15h"FREEVER",INT 2D/AL=17h"FREEVER"
--------U-2D--14-----------------------------
INT 2D - FREEVER - ENABLE TSR
    AL = 14h
    AH = AMIS multiplex number for FREEVER
Return: AL = FFh if successful
SeeAlso: INT 2D/AL=12h"FREEVER",INT 2D/AL=15h"FREEVER",INT 2D/AL=16h"FREEVER"
--------U-2D--15-----------------------------
INT 2D - FREEVER - DISABLE TSR
    AL = 15h
    AH = AMIS multiplex number for FREEVER
Return: AL = FFh if successful
SeeAlso: INT 2D/AL=12h"FREEVER",INT 2D/AL=14h"FREEVER",INT 2D/AL=16h"FREEVER"
--------U-2D--16-----------------------------
INT 2D - FREEVER - GET TSR STATUS
    AL = 16h
    AH = AMIS multiplex number for FREEVER
Return: AL = FFh if successful
        BL = status
        01h resident and active
        02h resident and inactive
SeeAlso: INT 2D/AL=12h"FREEVER",INT 2D/AL=15h"FREEVER",INT 2D/AL=17h"FREEVER"
--------U-2D--17-----------------------------
INT 2D - FREEVER - GET TaskMAX STATUS AT INSTALLATION
    AL = 17h
    AH = AMIS multiplex number for FREEVER
Return: AL = FFh if successful
        BL = status
        00h if TaskMAX not loaded before SETDRVER
        FFh if TaskMAX was loaded before SETDRVER
Program: FREEVER is an AMIS-conformant freeware DOS version-faking TSR similar
      to SETVER for any DOS-compatible OS, written by Matthias Paul
SeeAlso: INT 2D/AL=12h"FREEVER",INT 2D/AL=14h"FREEVER",INT 2D/AL=16h"FREEVER"
--------U-2D--20-----------------------------
INT 2D - DTown Utilities v1.40+ - GET POP-UP HANDLER ADDRESS
    AL = 20h
Return: AL = FFh if available
        DX:DI -> DTU popup-handler
Program: DTown Utilities is a freeware programmer's utility TSR by Jeroen van
      Disseldorp
Note:    this function is only available if the extended API has been installed
      in the resident portion
SeeAlso: INT 2D/AL=10h"DTown",INT 2D/AL=21h,INT 2D/AL=50h,INT 2D/AL=51h
SeeAlso: INT 03"DTown"
--------U-2D--21-----------------------------
INT 2D - DTown Utilities v1.40+ - POP UP
    AL = 21h
    BL = which utility to bring up
        00h active utility
        01h help screen
        0Ah ASCII table
        0Bh memory view
        0Ch CPU status
        0Dh calculator
        0Eh miscellaneous
        0Fh file viewer
        10h disassembler
Return: AL = status
        00h already active
        FFh popped up successfully
    BX = 0000h
Note:    this function is only available if the extended API has been installed
      in the resident portion
SeeAlso: INT 2D/AL=10h"DTown",INT 2D/AL=20h,INT 2D/AL=50h
--------U-2D--50-----------------------------
INT 2D - DTown Utilities v1.40+ - MEMORY VIEW SET ADDRESS
    AL = 50h
    CX:DX = new address for start of memory view utility's display
Note:    this function is only available if the extended API has been installed
      in the resident portion
Return: AL = FFh if supported
SeeAlso: INT 2D/AL=10h"DTown",INT 2D/AL=20h,INT 2D/AL=21h,INT 2D/AL=51h
--------U-2D--51-----------------------------
INT 2D - DTown Utilities v1.40+ - MEMORY VIEW SET REFERENCE
    AL = 51h
    BL = reference ("bookmark") number
    CX:DX = new address for reference
Return: AL = status
        00h invalid index
        FFh reference set
Note:    this function is only available if the extended API has been installed
      in the resident portion
Program: DTown Utilities is a shareware programmer's utility TSR by Jeroen van
      Disseldorp
SeeAlso: INT 2D/AL=10h"DTown",INT 2D/AL=20h,INT 2D/AL=50h
--------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 IEEE 1284.3 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"Enhanced Parallel Port",#0530,#1905
--------l-2E---------------------------------
INT 2E U - DOS 2+ - PASS COMMAND TO COMMAND INTERPRETER FOR EXECUTION
    DS:SI -> commandline to execute (see #1920)
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 DOS commandline:
Offset    Size    Description    (Table 1920)
 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 have proposed 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"ALTERNATE MULTIPLEX"
--------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 #1921)
        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 POPUP vector table entry:
Offset    Size    Description    (Table 1921)
 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 #1922)
    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 CiriSOFT author_name_ver table:
Offset    Size    Description    (Table 1922)
 -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 (see #1923)
 -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 #1924)
 -6    WORD    offset to extra_area table (see #1925,#1923 [bit 7])
 -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)

Bitfields for CiriSOFT characteristics byte:
Bit(s)    Description    (Table 1923)
 0-2    type
    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)
 3-6    reserved
 7    set if extra_table defined and supported (see #1925)
SeeAlso: #1922

Format of CiriSOFT vector_area table:
Offset    Size    Description    (Table 1924)
 -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
SeeAlso: #1922

Format of extra_area table (needed only to improve relocation feature):
Offset    Size    Description    (Table 1925)
 00h    WORD    offset to external_ctrl table (see #1926)
        0000h if not supported
 02h    WORD    reserved for future use (0)
SeeAlso: #1922

Format of CiriSOFT external_ctrl table:
Offset    Size    Description    (Table 1926)
 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 - GIVE PRINT A TIME SLICE
    AX = 0080h
Return: after PRINT executes
Notes:    PRINT returns AL=01h if AH=00h but AL is not 80h on entry
    this function is not supported by the Novell DOS 7 PRINT.COM
--------N-2F00D8-----------------------------
INT 2F - Personal NetWare - VLM - ???
    AX = 00D8h
    ???
Return: ???
Note:    hooked by one of the .VLMs loaded by VLM.EXE v1.10, but apparently a
      NOP
--------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 3.0+ PRINT - INSTALLATION CHECK
    AX = 0100h
Return: AL = status
        00h not installed
        01h not installed, but not OK to install
        FFh installed
        AH = 00h (Novell DOS 7)
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 3.0+ PRINT - SUBMIT FILE FOR PRINTING
    AX = 0101h
    DS:DX -> submit packet (see #1927)
Return: CF clear if successful
        AL = status
        01h added to queue
        9Eh now printing
    CF set on error
        AX = error code (see #1928,#1020 at INT 21/AH=59h/BX=0000h)
SeeAlso: AX=0102h

Format of PRINT submit packet:
Offset    Size    Description    (Table 1927)
 00h    BYTE    level (must be 00h)
 01h    DWORD    pointer to ASCIZ filename (no wildcards)

(Table 1928)
Values for PRINT error code:
 0001h    invalid function
 0002h    file not found
 0003h    path not found
 0004h    out of file handles
 0005h    access denied
 0008h    print queue full
 0009h    spooler busy
 000Ch    name too long
 000Fh    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 #1927)
    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 #1928)
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 3.0+ PRINT - 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 #1928)
SeeAlso: AX=0101h,AX=0103h
--------c-2F0103-----------------------------
INT 2F - DOS 3.0+ PRINT - CANCEL ALL FILES IN PRINT QUEUE
    AX = 0103h
Return: CF clear if successful
    CF set on error
        AX = error code (see #1928)
SeeAlso: AX=0102h
--------c-2F0104-----------------------------
INT 2F - DOS 3.0+ PRINT - 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 #1928)
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 3.0+ PRINT - RESTART PRINT QUEUE AFTER STATUS READ
    AX = 0105h
Return: CF clear if successful
    CF set on error
        AX = error code (see #1928)
Desc:    restart PRINT's activities once an application finishes examining the
      print queue
SeeAlso: AX=0104h
--------c-2F0106-----------------------------
INT 2F - DOS 3.3+ PRINT - GET PRINTER DEVICE
    AX = 0106h
Return: CF set if files in print queue
        AX = error code 0008h (queue full)
        DS:SI -> device driver header (see #0987)
    CF clear if print queue empty
        AX = 0000h
Desc:    determine which device, if any, PRINT is currently using for output
Notes:    undocumented prior to the release of MS-DOS 5.0
    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 3.0+ 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 3.0+ CRITICAL ERROR HANDLER - EXPAND ERROR INTO STRING
    AH = 05h
---DOS 3.x---
    AL = extended error code (not zero)
---DOS 4.0+ ---
    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 3.0+ 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 3.0+ ASSIGN - GET DRIVE ASSIGNMENT TABLE
    AX = 0601h
Return: ES = segment of ASSIGN work area and assignment table
Note:    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,AX=AF14h"WinDOS"
--------D-2F0800-----------------------------
INT 2F U - DRIVER.SYS support - INSTALLATION CHECK
    AX = 0800h
Return: AL = status
        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; it is always present in DOS 3.2+
Note:    supported by DR DOS 5.0 and Novell DOS 7
--------D-2F0801-----------------------------
INT 2F U - DRIVER.SYS support - ADD NEW BLOCK DEVICE
    AX = 0801h
    DS:DI -> drive data table (see #1935,#1936,#1937)
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 and Novell DOS 7
SeeAlso: AX=0803h
--------D-2F0802-----------------------------
INT 2F U - DRIVER.SYS support - EXECUTE DEVICE DRIVER REQUEST
    AX = 0802h
    ES:BX -> device driver request header (see #1931)
Return: request header updated as per requested operation
    STACK:    WORD    original flags from INT call (left by RETF in device
              driver, at least in DOS 5.0-6.22)
Notes:    supported by DR DOS 5.0
    DOS 3.2 executes this function on any AL value from 02h through F7h;
      DOS 4.0+ executes this function on AL=02h and AL=04h-F7h
    the command codes (see #1929) 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
    supported by Novell DOS 7
SeeAlso: AX=0800h,AX=0801h,AX=0803h,AX=1510h,INT 21/AH=52h,INT 21/AH=99h
SeeAlso: INT 21/AH=9Ah

(Table 1929)
Values for device driver 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 3.0+) DEVICE OPEN
 0Eh    (DOS 3.0+) DEVICE CLOSE
 0Fh    (DOS 3.0+) REMOVABLE MEDIA (block devices)
 10h    (DOS 3.0+) 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 5.0+) 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

Bitfields for device request status:
Bit(s)    Description    (Table 1930)
 15    error
 14-11    reserved
 10    ??? set by DOS kernel on entry to some driver calls
 9    busy
 8    done (may be clear on return under European MS-DOS 4.0)
 7-0    error code if bit 15 set (see #1932)

Format of device driver request header:
Offset    Size    Description    (Table 1931)
 00h    BYTE    length of request header
 01h    BYTE    subunit within device driver
 02h    BYTE    command code (see #1929)
 03h    WORD    status (filled in by device driver) (see #1930)
---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    (ret) number of units
 0Eh    DWORD    (call) pointer to DOS device helper function (see #1933)
              (European MS-DOS 4.0 only)
        (call) pointer past end of memory available to driver (DOS 5+)
        (ret) address of first free byte following driver
 12h    DWORD    (call) pointer to commandline arguments
        (ret) pointer to BPB array (block drivers) or
              0000h:0000h (character drivers)
 16h    BYTE    (DOS 3.0+) 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    (ret) error-message flag
        0001h MS-DOS should display error msg on init failure
---command code 01h---
 0Dh    BYTE    media descriptor
 0Eh    BYTE    (ret) media status
        00h don't know
        01h media has not changed
        FFh media has been changed
 0Fh    DWORD    (ret, DOS 3.0+) pointer to previous volume ID if the
          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 #1004 at INT 21/AH=53h)
---command codes 03h,0Ch---
          (see also INT 21/AX=4402h"DOS 2+",INT 21/AX=4403h"DOS")
 0Dh    BYTE    media descriptor (block devices only)
 0Eh    DWORD    transfer address
 12h    WORD    (call) number of bytes to read/write
        (ret) actual number of bytes read or written
---command codes 04h,08h,09h (except Compaq DOS 3.31, DR DOS 6)---
 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 3.0+) pointer to volume ID if error 0Fh returned
 1Ah    DWORD    (DOS 4.0+) 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 codes 04h,08h,09h (Compaq DOS 3.31, DR DOS 6)---
 0Dh    BYTE    media descriptor (block devices only)
 0Eh    DWORD    transfer address
 12h    WORD    byte count (character devices) or sector count (block devices)
 14h    DWORD    32-bit starting sector number (block devices only)
    Note:    to reliably determine which variant of the request block for
          functions 04h,08h,09h has been passed to the driver, check
          the length field as well as the word at offset 14h.  If the
          length is 1Eh and 14h=FFFFh, use the DWORD at 1Ah as the
          starting sector number; if the length is 18h, use the DWORD
          at 14h; otherwise, use the WORD at 14h.
---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
        (ret) 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 (see #0987)
        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
        (number of sectors between consecutive portions)
---command code 83h---
 0Dh    BYTE    addressing mode
        00h HSG (default)
        01h Phillips/Sony Red Book
 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
        00h HSG (default)
        01h Phillips/Sony Red Book
 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
        00h HSG (default)
        01h Phillips/Sony Red Book
 0Eh    DWORD    transfer address (ignored in write mode 0)
 12h    WORD    number of sectors to write
 14h    DWORD    starting sector number (also see 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
        (number of sectors between consecutive portions)

(Table 1932)
Values for device driver 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

(Table 1933)
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 #1934)
        Note:    the queue size field must be set before calling
        0Dh "QueueWrite" put a character in the queue
        DS:BX -> character queue (see #1934)
        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 #1934)
        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 European MS-DOS 4.0 character queue:
Offset    Size    Description    (Table 1934)
 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 4.0+ DRIVER.SYS support - GET DRIVE DATA TABLE LIST
    AX = 0803h
Return: DS:DI -> first drive data table in list (see #1935,#1936,#1937)
Note:    not available under DR DOS 5.0, but supported by Novell DOS 7 (using
      the MS-DOS 4+ data table format)
SeeAlso: AX=0801h

Format of DOS 3.30 drive data table:
Offset    Size    Description    (Table 1935)
 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 #0903 at INT 21/AX=440Dh"DOS 3.2+")
 29h    WORD    bit flags describing drive (see #1938)
 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)
SeeAlso: #1936,#1937

Format of COMPAQ DOS 3.31 drive data table:
Offset    Size    Description    (Table 1936)
 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 #1937)
 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 #0903 at INT 21/AX=440Dh"DOS 3.2+")
 35h    WORD    bit flags describing drive (see #1938)
 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)
SeeAlso: #1935,#1937

Format of DOS 4.0-7.0 drive data table:
Offset    Size    Description    (Table 1937)
 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 (refer to 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 #0903 at INT 21/AX=440Dh"DOS 3.2+")
 23h    WORD    bit flags describing drive (see #1938)
 25h    WORD    number of cylinders (for partition only, if hard disk)
 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
SeeAlso: #1935,#1936

Bitfields for flags describing drive:
Bit(s)    Description    (Table 1938)
 0    fixed media
 1    door lock ("changeline") supported
 2    current BPB locked
 3    all sectors in a track are the same size
 4    physical drive has multiple logical units
 5    current logical drive for shared physical drive
 6    disk change detected
 7    device parameters were changed (set DASD before formatting)
    (see #0902 at INT 21/AX=440Dh"DOS 3.2+")
 8    disk reformatted (BPB of current media was changed)
 9    access flag (fixed media only, disables reads and writes)
    (see #0908 at INT 21/AX=440Dh"DOS 3.2+")
--------f-2F1000-----------------------------
INT 2F - SHARE - INSTALLATION CHECK
    AX = 1000h
Return: AL = status
        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
Notes:    this function is also supported by SuperStor, a disk-compression
      program by Addstor which is bundled with DR DOS 6.0, and the
      Novell DOS 7 DELWATCH.EXE
    the default handler for the pointer set by this call under DELWATCH
      simply returns with CF set
SeeAlso: AX=1000h,AX=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-2F10FE-----------------------------
INT 2F U - Novell DOS 7 DELWATCH.EXE - INSTALLATION CHECK
    AX = 10FEh
Return: AX = 20FFh if installed and active
        DX:BX -> private entry point (see #1939)

(Table 1939)
Call DELWATCH private entry point with:
    AH = function
        00h NOP???
        Return: AX = 0000h
            CX = 0004h (unsupported function)
        01h disable DELWATCH on drive
        AL = drive number (00h = A:)
        Return: AX = status (0000h if failed, FFFFh if successful)
        02h ???
        AL = drive number (00h = A:)
        ???
        Return: ???
        03h    ???
        AL = drive number (00h = A:)
        CX = ??? (0000h/0001h)
        ???
        Return: ???
        04h ???
        AL = drive number (00h = A:)
        ???
        Return: ???
        05h ???
        AL = drive number (00h = A:)
        ???
        Return: ???
        06h enable DELWATCH on drive
        AL = drive number with bit 7 set (80h = A:, etc.)
        BX = maximum files of same name in one directory to save
        CX = maximum files to save on this disk
        ???
        Return: AX = status
                0000h failed
                FFFFh successful
            CX = error code on failure
                (0004h if AL < 80h on entry)
        07h ???
        08h set file extensions list
        AL = sense (00h exclude named extensions, 01h only named ext.)
        DS:BX -> 31-byte ASCIZ extension list (three blank-padded bytes
              per extension)
        Return: AX = FFFFh (successful)
        09h    ???
        AL = drive number (00h = A:)
        ???
        Return: ???
        0Ah ???
        AL = drive number (00h = A:)
        ???
        Return: ???
        0Bh reset ???
        Return: AX = FFFFh (successful)
        see also function 0Dh
        0Ch check if drive enabled
        AL = drive number with bit 7 set (80h = A:, etc.)
        Return: AX = state
                0000h disabled or error (check CX)
                0001h drive enabled
            CX = error code (0004h invalid drive number)
        0Dh set ???
        BX = ???
        Return: AX = FFFFh (successful)
        see also function 0Bh
        0Eh ???
        AL = drive number (00h = A:)
        ???
        Return: ???
Return: AX = 0000h, CX = 0001h if DELWATCH busy
    registers unchanged if AH >= 0Fh on entry
--------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 #1020 at INT 21/AH=59h/BX=0000h)
    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 #1020 at INT 21/AH=59h/BX=0000h)
    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 #1020 at INT 21/AH=59h/BX=0000h)
    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 #1020 at INT 21/AH=59h/BX=0000h)
    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 #1020 at INT 21/AH=59h/BX=0000h)
    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 #1020 at INT 21/AH=59h/BX=0000h)
    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 #1020 at INT 21/AH=59h/BX=0000h)
    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 #1020 at INT 21/AH=59h/BX=0000h)
    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"DOS",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 #1020 at INT 21/AH=59h/BX=0000h)
    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 #1020 at INT 21/AH=59h/BX=0000h)
    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 4.0+) - 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 #1940)
    ES:DI -> SFT
        SFT DPB field -> DPB of drive containing file
    SS = DOS DS
Return: CF set on error
       AL = DOS error code (see #1020 at INT 21/AH=59h/BX=0000h)
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    (Table 1940)
 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 #1020 at INT 21/AH=59h/BX=0000h)
    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: CF clear if data valid
        AL = sectors per cluster
        AH = media ID byte
        BX = total clusters
        CX = bytes per sector
        DX = number of available clusters
    CF set if data invalid
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 #1020 at INT 21/AH=59h/BX=0000h)
    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 #1020 at INT 21/AH=59h/BX=0000h)
    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 #1020 at INT 21/AH=59h/BX=0000h)
    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 #1020 at INT 21/AH=59h/BX=0000h)
    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 #0749 at INT 21/AH=3Dh)
Return: CF set on error
        AX = DOS error code (see #1020 at INT 21/AH=59h/BX=0000h)
    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 #0748 at INT 21/AH=3Ch)
            high byte = 00h normal create, 01h create new file
Return: CF set on error
        AX = DOS error code (see #1020 at INT 21/AH=59h/BX=0000h)
    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 #0967 at 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 #1020 at INT 21/AH=59h/BX=0000h)
    CF clear if successful
        [DTA] = updated findfirst search data
            (bit 7 of first byte must be set)
        [DTA+15h] = standard directory entry for file (see #0700)
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,INT 21/AH=1Ah
--------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 #0967 at 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 #1020 at INT 21/AH=59h/BX=0000h)
    CF clear if successful
        [DTA] = updated findfirst search data
            (bit 7 of first byte must be set)
        [DTA+15h] = standard directory entry for file (see #0700)
Note:    this function is called by the DOS 3.1+ kernel
SeeAlso: AX=1119h,AX=111Ch,INT 21/AH=1Ah,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
    ES:DI -> DTA (MSDOS v5.0)
    [DTA] = 21-byte findfirst search data
          (see #0967 at INT 21/AH=4Eh)
Return: CF set on error
        AX = DOS error code (see #1020 at INT 21/AH=59h/BX=0000h)
    CF clear if successful
        [DTA] = updated findfirst search data
            (bit 7 of first byte must be set)
        [DTA+15h] = standard directory entry for file (see #0700)
Note:    this function is called by the DOS 3.1+ kernel
SeeAlso: AX=1119h,AX=111Bh,INT 21/AH=1Ah,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 #1020 at INT 21/AH=59h/BX=0000h)
    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 #1020 at INT 21/AH=59h/BX=0000h)
    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 #1020 at INT 21/AH=59h/BX=0000h)
    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: ???
Notes:    this function is called by the DOS 3.1+ kernel
    after calling this function, the kernel calls INT 2F/AX=111Dh
SeeAlso: AX=111Dh,INT 21/AH=4Ch,INT 60/DI=0601h
--------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 #1020 at INT 21/AH=59h/BX=0000h)
    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 #1020 at INT 21/AH=59h/BX=0000h)
--------N-2F1127BX4E57-----------------------
INT 2F - NetWare 4.0 - REMOTE FILE COPY
    AX = 1127h
    BX = 4E57h ('NW') (signature identifying this as a NetWare call)
    SI = source file handle
    DI = destination file handle
    DX:CX = number of bytes to copy, starting at current file position
Return: CF clear if successful
    CF set on error
        AX = error code (05h,06h,0Bh,11h,3Bh) (see #1020)
    DX:CX = number of bytes successfully copied (file position updated)
Notes:    this is the only call which may be made directly to the NetWare
      redirector from an application
    COMMAND.COM's COPY and DOS's XCOPY reportedly call INT 21/AX=1127h in
      order to speed up copies between files on the same network server;
      if error code 11h (not same device) is returned, the copy is
      performed in the usual manner.  However, no such calls appear to
      be present in MS-DOS 6.22.
--------N-2F1128-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - UNUSED
    AX = 1128h
Return: CF set
        AX = 0001h (invalid function) (see #1020 at INT 21/AH=59h/BX=0000h)
--------N-2F1129-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - UNUSED
    AX = 1129h
Return: CF set
        AX = 0001h (invalid function) (see #1020 at INT 21/AH=59h/BX=0000h)
--------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 #1020 at INT 21/AH=59h/BX=0000h)
    CF clear if successful
Note:    this function is called by the DOS 4.0 kernel
--------N-2F112C-----------------------------
INT 2F CU - NETWORK REDIRECTOR (DOS 4.0+) - "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 4.0+) - 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 #1112 at 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 4.0+ kernel
BUG:    this function is not called correctly under some DOS versions
      (at least 5.0 and 6.2):
        the file attribute on the stack is not correct if the action
          code is 11h,
        the result code in CX is not passed back to the application.
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 #1020 at INT 21/AH=59h/BX=0000h)
    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: ???
SeeAlso: AX=1100h,AX=1181h,AX=118Eh
--------N-2F1181-----------------------------
INT 2F - LAN Manager Enhanced DOS Services - SET USER NAME???
    AX = 1181h
    ???
Return: ???
SeeAlso: AX=1100h,AX=1180h
--------N-2F1182-----------------------------
INT 2F - LAN Manager Enhanced DOS Services - INSTALL SERVICE
    AX = 1182h
    ???
Return: ???
SeeAlso: AX=1100h,AX=1180h
--------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 #1941)
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 LAN Manager DosReadAsynchNmPipe stack frame:
Offset    Size    Description    (Table 1941)
 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 #1942)
Return: CF clear if successful
    CF set if error
        AX = error code
SeeAlso: AX=1186h,AX=1191h,INT 21/AX=5F3Ah

Format of LAN Manager DosReadAsynchNmPipe stack frame:
Offset    Size    Description    (Table 1942)
 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 (see #1943)
Return: CF clear if successful
    CF set if error
        AX = error code
SeeAlso: AX=1186h,AX=1191h

Format of LAN Manager DosReadAsynchNmPipe2 stack frame:
Offset    Size    Description    (Table 1943)
 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 #1944)
Return: CF clear if successful
    CF set if error
        AX = error code
SeeAlso: AX=118Fh,AX=1190h,INT 21/AX=5F3Ah

Format of LAN Manager DosReadAsynchNmPipe2 stack frame:
Offset    Size    Description    (Table 1944)
 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 3.0+ internal - INSTALLATION CHECK
    AX = 1200h
Return: AL = FFh (for compatibility with other INT 2F functions)
--------D-2F1201-----------------------------
INT 2F U - DOS 3.0+ 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 3.0+ internal - GET INTERRUPT ADDRESS
    AX = 1202h
    STACK: WORD vector number
Return: ES:BX -> interrupt vector (DWORD containing handler's address)
    STACK unchanged
--------D-2F1203-----------------------------
INT 2F U - DOS 3.0+ 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 3.0+ 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 3.0+ 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 3.0+ internal - INVOKE CRITICAL ERROR
    AX = 1206h
    DI = error code
    BP:SI -> device driver header (see #0987)
    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 3.0+ 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 3.0+ 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 3.0+ 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 3.0+ 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 3.0+ 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 #1020 at INT 21/AH=59h/BX=0000h)
    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 3.0+ 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 3.0+ 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 #1006 at INT 21/AX=5700h)
    DX = current time in packed format (see #1005 at INT 21/AX=5700h)
SeeAlso: INT 21/AH=2Ah,INT 21/AH=2Ch
--------D-2F120E-----------------------------
INT 2F U - DOS 3.0+ 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 3.0+ 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 3.0+ 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 3.0+ 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 3.0+ 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 3.0+ internal - UPPERCASE CHARACTER
    AX = 1213h
    STACK: WORD character to convert to uppercase
Return: AL = uppercase character
    STACK unchanged
--------D-2F1214-----------------------------
INT 2F U - DOS 3.0+ 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
    CF clear if pointers equal, CF set if not
--------D-2F1215-----------------------------
INT 2F U - DOS 3.0+ 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 3.0+ 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
        BX = relative entry number in system file table containing entry
        AX destroyed
    CF set if BX greater than FILES=
Note:    supported by DR DOS 5+
SeeAlso: AX=1220h
--------D-2F1217-----------------------------
INT 2F U - DOS 3.0+ 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 3.0+ 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 3.0+ 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 3.0+ 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 3.0+ 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"DATE"
--------D-2F121C-----------------------------
INT 2F U - DOS 3.0+ 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 3.0+ 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 3.0+ 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 3.0+ 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 3.0+ 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 3.0+ 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 3.0+ 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/BX=0000h,INT 21/AX=5D0Ah
--------D-2F1223-----------------------------
INT 2F U - DOS 3.0+ 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 3.0+ 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 3.0+ 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 #1020 at INT 21/AH=59h/BX=0000h)
    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"DOS"
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"DOS"
--------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 (see #1945,#1946)
        (entry point not set if SI = FFFFh for DOS 4.0+)
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

(Table 1945)
Values DOS 3.30+ FASTOPEN entry point 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
SeeAlso: #1946,#1947

(Table 1946)
Values 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 ???
SeeAlso: #1945,#1947

(Table 1947)
Values 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 ???
        ???
SeeAlso: #1945,#1946
--------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 and Novell DOS 7, it
      always returns 0000h:0000h prior to Novell DOS 7 Update 15
SeeAlso: INT 21/AH=52h
--------D-2F122D-----------------------------
INT 2F U - DOS 3.3+ internal - GET EXTENDED ERROR CODE
    AX = 122Dh
    SS = DOS DS
Return: AX = current extended error code
SeeAlso: AX=1222h,INT 21/AH=59h/BX=0000h
--------D-2F122E-----------------------------
INT 2F U - DOS 4.0+ internal - GET OR SET ERROR TABLE ADDRESSES
    AX = 122Eh
    DL = subfunction
        00h get standard DOS error table (see #1948)
        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 #1949)
        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/BX=0000h

Format of DOS 4.x error table:
Offset    Size    Description    (Table 1948)
 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

(Table 1949)
Call error retrieval function with:
    AX = error number (see #1950)
    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

(Table 1950)
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-2F12FFBL00-------------------------
INT 2F - FreeDOS - FDAK-DDT - INSTALLATION CHECK / STATUS CHECK
    AX = 12FFh
    BL = 00h
Return: AL = DDh if installed
        BH = state (00h disabled, nonzero enabled)
        BL = readonly flag (00h writable, nonzero read-only)
Program: FDAK-DDT is the FreeDOS Alternative Kernel Device Drivers Testing
      release by Yury A. Semenov
SeeAlso: AX=12FFh/BL=07h
--------O-2F12FFBL01-------------------------
INT 2F - FreeDOS - FDAK-DDT - ENABLE FDAK DRIVERS
    AX = 12FFh
    BL = 01h
SeeAlso: AX=12FFh/BL=00h,AX=12FFh/BL=02h
--------O-2F12FFBL02-------------------------
INT 2F - FreeDOS - FDAK-DDT - DISABLE FDAK DRIVERS
    AX = 12FFh
    BL = 02h
SeeAlso: AX=12FFh/BL=00h,AX=12FFh/BL=01h
--------O-2F12FFBL03-------------------------
INT 2F - FreeDOS - FDAK-DDT - SWITCH BLOCK DEVICE TO READ-ONLY
    AX = 12FFh
    BL = 03h
    ???
SeeAlso: AX=12FFh/BL=00h,AX=12FFh/BL=04h
--------O-2F12FFBL04-------------------------
INT 2F - FreeDOS - FDAK-DDT - SWITCH BLOCK DEVICE TO READ-WRITE
    AX = 12FFh
    BL = 04h
    ???
SeeAlso: AX=12FFh/BL=00h,AX=12FFh/BL=03h
--------O-2F12FFBL05-------------------------
INT 2F - FreeDOS - FDAK-DDT - TURN ACTIVITY INDICATOR ON
    AX = 12FFh
    BL = 05h
Note:    not yet implemented as of January 1996
SeeAlso: AX=12FFh/BL=00h,AX=12FFh/BL=06h
--------O-2F12FFBL06-------------------------
INT 2F - FreeDOS - FDAK-DDT - TURN ACTIVITY INDICATOR OFF
    AX = 12FFh
    BL = 06h
Note:    not yet implemented as of January 1996
SeeAlso: AX=12FFh/BL=00h,AX=12FFh/BL=05h
--------O-2F12FFBL07-------------------------
INT 2F - FreeDOS - FDAK-DDT - UNINSTALL
    AX = 12FFh
    BL = 07h
Return: ES = segment of FDAK memory block
Note:    the caller must free the memory block returned in ES
      (via INT 21/AH=49h)
SeeAlso: AX=12FFh/BL=00h
--------m-2F12FFBX0006-----------------------
INT 2F U - DR DOS 6, Novell DOS 7 - EMM386.EXE - 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
Notes:    this functionality is provided by EMM386, and partially supported by
      HIDOS.SYS
    BL specifies which program handles the call, BH is the function number
SeeAlso: AX=D201h/BX=4849h
--------O-2F12FFBX0000-----------------------
INT 2F U - Novell DOS 7 - GET ???
    AX = 12FFh
    BX = 0000h
Return: AX = 0000h if supported
    DX = ??? (internal data)
SeeAlso: AX=12FFh/BX=0001h
--------O-2F12FFBX0001-----------------------
INT 2F U - Novell DOS 7 - SET ???
    AX = 12FFh
    BX = 0001h
    DX = new value for ???
Return: AX = 0000h if supported
SeeAlso: AX=12FFh/BX=0000h
--------O-2F12FFBX0002-----------------------
INT 2F U - Novell DOS 7 - GET ??? SIZE
    AX = 12FFh
    BX = 0002h
Return: AX = 0000h if supported
    DX = size of/required-for ??? in paragraphs
SeeAlso: AX=12FFh/BX=0003h
--------O-2F12FFBX0003-----------------------
INT 2F U - Novell DOS 7 - SET ???
    AX = 12FFh
    BX = 0003h
    DX = new value for ???
Return: AX = 0000h if supported
SeeAlso: AX=12FFh/BX=0002h
--------O-2F12FFBX0007-----------------------
INT 2F U - Novell DOS 7 - SCRIPT.EXE - GET ???
    AX = 12FFh
    BX = 0007h
    CX = 0000h
Return: CF clear if installed
        AX = 0000h
        BX = ??? (4426h)
        CX = ??? (0068h)
        DX = PSP segment of resident code???
        SI = ??? (4AFAh)
        ES = resident code segment
--------O-2F12FFBX0009-----------------------
INT 2F U - Novell DOS 7 - SET ???
    AX = 12FFh
    BX = 0009h
    DX = new value for ???
Return: ???
Note:    the DX value is stored at offset 66h in SYSVARS and offset 18h in
      the Novell DOS 7 internal variable table
--------m-2F12FFBX0106-----------------------
INT 2F U - Novell DOS 7 - EMM386.EXE - GET VERSION???
    AX = 12FFh
    BX = 0106h
Return: CF clear if successful
        AX = 0000h (successful)
        BX = EDC0h (signature)
        CL = memory manager variant (02h,03h)
        (02h when DPMI/VCPI disabled, 03h when DPMI/VCPI loaded)
        CH = ??? (00h)
        DX = version??? (0300h for v3.0)
        ES = segment of EMM386 low-memory stub
Notes:    BL specifies which program handles the call, BH is the function number
    if the word at ES:0012h is nonzero, if contains the offset within
      segment ES of the CEMM-compatible entry point (see #1951)
    if no other program has hooked INT 67, an alternate installation
      check is to test for the string
      "NOVELL EXPANDED MEMORY MANAGER 386" at offset 14h in the INT 67
      handler's segment; the word immediately preceding this string
      contains the offset of the API entry point if it is nonzero
Index:    entry point;Novell EMM386

(Table 1951)
Call Novell EMM386.EXE entry point with:
    AH = 00h get memory manager's status???
        ???
    AH = 01h set memory manager's status???
        ???
    AH = 02h Weitek coprocessor support???
        AL = subfunction???
    more functions???
SeeAlso: #0855 at INT 21/AX=4402h/SF=02h,#2915 at INT 67/AX=FFA5h
--------m-2F12FFBL06-------------------------
INT 2F U - Novell DOS 7 - EMM386.EXE - ???
    AX = 12FFh
    BL = 06h
    BH = function (02h-09h)
    ???
Return: ???
--------O-2F12FFBX0EDC-----------------------
INT 2F U - Novell DOS 7 - EMM386.EXE - CHECK IF MULTITASKING SUPPORT LOADED???
    AX = 12FFh
    BX = 0EDCh ('EDC' = Novell European Development Center)
Return: AX = 0000h if ??? loaded
        CF clear
        BX = 0000h
Notes:    called by Novell DOS 7 TaskMgr
    if this function returns with AX=0000h, then the code necessary to
      support the API on INT 2F/AX=2780h is loaded and that API becomes
      available for use
    because the request is handled on the initial trap to the memory
      manager caused by INT instructions, this function must be invoked
      with an actual INT 2F instruction instead of some simulation such
      as a far call to the address in the interrupt vector table
SeeAlso: AX=2780h/CL=01h,AX=2780h/CL=02h,AX=2780h/CL=03h,AX=2780h/CL=04h
--------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 #1952)
    BX = new code page (see #1099 at 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    (Table 1952)
 00h  8 BYTEs    ???
 08h 64 BYTEs    name of country information file
 48h    WORD    system code page (see #1099 at INT 21/AX=6602h)
 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 #1099 at INT 21/AX=6602h)
    DX = country code (see #0747 at INT 21/AH=38h)
    DS:SI -> internal code page structure (see #1952)
    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 (see #1953)
SeeAlso: AX=1400h"POPUP",AX=1401h"POPUP",AX=1403h"POPUP"

(Table 1953)
Values for POPUP error code:
 0001h    process does not own screen
 0004h    unknown error
 0005h    invalid pointer
--------U-2F1403-----------------------------
INT 2F CU - NLSFUNC.COM - SET CODE PAGE
    AX = 1403h
    DS:SI -> internal code page structure (see #1952)
    BX = code page (see #1099 at INT 21/AX=6602h)
    DX = country code (see #0747 at 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 #1953)
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 #1099 at INT 21/AX=6602h)
    DX = country code (see #0747 at INT 21/AH=38h)
    DS:SI -> internal code page structure (see #1952)
    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 #1099 at INT 21/AX=6602h)
    DX = country ID (FFFFh=current country) (see #0747 at 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: #1954,AX=14FFh,INT 21/AH=65h

Format of DR DOS COUNTRY.SYS file:
Offset    Size    Description    (Table 1954)
 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 (see #1099 at INT 21/AX=6602h)
     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 (see #1099 at INT 21/AX=6602h)
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
BUG:    this function may return an incorrect starting drive letter when
      INTERLNK is installed
SeeAlso: AX=150Ch,AX=15FFh,INT 2F/AX=D000h"Lotus"
--------c-2F1500CH90-------------------------
INT 2F U - CDBLITZ v2.11 - INSTALLATION CHECK
    AX = 1500h
    CH = 90h (function number)
    BX = 1234h (magic value for CDBLITZ)
Return: CX = 1234h if installed
        CF clear
        DX = BCD version number (DH = major, DL = minor)
Program: CDBLITZ is a CD-ROM cache by Blitz 'n' Software, Inc.
SeeAlso: AX=1500h/CH=99h
--------c-2F1500CH91-------------------------
INT 2F U - CDBLITZ v2.11 - GET STATISTICS
    AX = 1500h
    CH = 91h (function number)
    BX = 1234h (magic value for CDBLITZ)
Return: CF clear
    ES:BX -> statistics record (see #1955)
SeeAlso: AX=1500h/CH=90h,AX=1500h/CH=97h

Format of CDBLITZ statistics record:
Offset    Size    Description    (Table 1955)
 00h    WORD    cache mode (see also AX=1500h/CH=94h)
        0001h 'min', 0002h 'max'
 02h    DWORD    number of read calls???
 06h    DWORD    total number of sectors read
 0Ah    DWORD    unused??? (zero)
 0Eh    DWORD    number of cache hit sectors
 12h    WORD    cache size in KB
 14h    WORD    unused??? (zero)
 16h    WORD    cache state (0000h disabled, 0001h enabled)
--------c-2F1500CH92-------------------------
INT 2F U - CDBLITZ v2.11 - ENABLE CACHE
    AX = 1500h
    CH = 92h (function number)
    BX = 1234h (magic value for CDBLITZ)
Return: CF clear
SeeAlso: AX=1500h/CH=90h,AX=1500h/CH=93h,AX=1500h/CH=94h
--------c-2F1500CH93-------------------------
INT 2F U - CDBLITZ v2.11 - DISABLE CACHE
    AX = 1500h
    CH = 93h (function number)
    BX = 1234h (magic value for CDBLITZ)
Return: CF clear
SeeAlso: AX=1500h/CH=90h,AX=1500h/CH=92h,AX=1500h/CH=95h
--------c-2F1500CH94-------------------------
INT 2F U - CDBLITZ v2.11 - SET 'MAX' MODE (CACHE BOTH DIRECTORIES AND DATA)
    AX = 1500h
    CH = 94h (function number)
    BX = 1234h (magic value for CDBLITZ)
Return: CF clear
SeeAlso: AX=1500h/CH=90h,AX=1500h/CH=92h,AX=1500h/CH=95h
--------c-2F1500CH95-------------------------
INT 2F U - CDBLITZ v2.11 - SET 'MIN' MODE (CACHE ONLY DIRECTORY ENTRIES)
    AX = 1500h
    CH = 95h (function number)
    BX = 1234h (magic value for CDBLITZ)
Return: CF clear
SeeAlso: AX=1500h/CH=90h,AX=1500h/CH=94h
--------c-2F1500CH96-------------------------
INT 2F U - CDBLITZ v2.11 - FLUSH CACHE
    AX = 1500h
    CH = 96h (function number)
    BX = 1234h (magic value for CDBLITZ)
Return: CF clear
Note:    this function resets the counts for number of sectors read and number
      of cache hits, but no other values in the statistics record
      (see #1955)
SeeAlso: AX=1500h/CH=90h
--------c-2F1500CH97-------------------------
INT 2F U - CDBLITZ v2.11 - GET CACHE STATISTICS
    AX = 1500h
    CH = 97h (function number)
    BX = 1234h (magic value for CDBLITZ)
Return: CF clear
    AL = cache mode (01h 'min', 02h 'max') (see also AX=1500h/CH=94h)
    AH = cache state (00h disabled, 01h enabled)
    BX = cache size in KB
    DX:CX = total number of reads
    DI:SI = number of cache hits
SeeAlso: AX=1500h/CH=90h,AX=1500h/CH=91h
--------c-2F1500CH99-------------------------
INT 2F U - CDBLITZ v2.11 - UNINSTALL
    AX = 1500h
    CH = 99h (function number)
    BX = 1234h (magic value for CDBLITZ)
Return: CF clear
    ???
Program: CDBLITZ is a CD-ROM cache by Blitz 'n' Software, Inc.
SeeAlso: AX=1500h/CH=90h
--------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 (see #0987)
Note:    reportedly returns AX=0000h and an invalid address under Windows95
SeeAlso: AX=1510h
--------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)
Note:    This function was not supported by Novell DOS 7 NWCDEX prior to the
      08/16/94 update
--------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 (0Fh invalid drive,15h not ready)
    CF clear if successful
Note:    reportedly returns error 15h (not ready) under Windows95
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 = support status
        0000h if drive not supported
        nonzero if supported
SeeAlso: AX=150Dh
--------d-2F150C-----------------------------
INT 2F - CD-ROM v2.00+ - GET MSCDEX.EXE VERSION (GET VERSION)
    AX = 150Ch
Return: BH = major version
    BL = minor version
Notes:    MSCDEX.EXE versions prior to 2.00 return BX=0000h
    Corel's CORELCDX.COM v1.01d returns 2.20, v1.12a returns 2.21
    Meridian Data's CDNETEX.EXE returns its own version number, e.g. 4.70
    Windows95 returns v2.95
SeeAlso: AX=1500h"CD-ROM"
--------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 #1956,#1957)
         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)
Note:    this function was not supported by Novell DOS 7 NWCDEX prior to the
      08/16/94 update

Format of CD-ROM directory entry (direct copy):
Offset    Size    Description    (Table 1956)
 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
        (seventh byte is offset from GMT in 15-minute increments)
 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
SeeAlso: #1957,#0700

Format of CD-ROM directory entry (canonicalized):
Offset    Size    Description    (Table 1957)
 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
SeeAlso: #1956
--------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 #1931 at AX=0802h)
Note:    MSCDEX initializes the device driver request header's subunit field
      based on the drive number specified in CX
BUG:    Novell DOS 7 NWCDEX prior to the 12/13/94 update did not initialize
      the subunit field
SeeAlso: AX=0802h
--------d-2F15FFBX0000-----------------------
INT 2F - CD-ROM - CORELCDX - INSTALLATION CHECK
    AX = 15FFh
    BX = 0000h
Return: BX = ABCDh if CORELCDX loaded
Note:    Corel's CORELCDX.COM is a replacement for MSCDEX.EXE; it also supports
      the standard MSCDEX installation check calls AX=1500h and AX=150Ch
SeeAlso: AX=1500h"CD-ROM",AX=150Ch
--------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 and Windows95 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 C - MS Windows/386 - GET INSTANCE DATA
    AX = 1603h
Return: AX = 5248h ('RH') if supported
        DS:SI -> Windows/386 instance data (see #1958)
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    (Table 1958)
 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 ENHANCED 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 #1959)
    DS:SI -> virtual86 mode enable/disable callback or 0000h:0000h
          (see #1962)
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
    Novell DOS v7.0 (Update 8 - Update 11) TASKMGR in multitasking mode
      uses this broadcast, even if TASKMGR.INI sets WinPresent= to OFF
    Microsoft's EMM386.EXE for DOS 5+ when installed with the NOEMS option
      changes its driver name from EMMQXXX0 to EMMXXXX0 while Windows is
      active
SeeAlso: AX=1606h,AX=1608h,AX=4B05h

Format of Windows Startup Information Structure:
Offset    Size    Description    (Table 1959)
 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 #1961)
        (only used if above nonzero)
 0Eh    DWORD    pointer to instance data records (see #1960) or 0000h:0000h

Format of one Instance Item in array:
Offset    Size    Description    (Table 1960)
 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    (Table 1961)
 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

(Table 1962)
Values Windows virtual mode enable/disable procedure is 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 ENHANCED 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
    Novell DOS v7.0 (Update 8 - Update 15) TASKMGR in multitasking mode
      uses this broadcast, even if TASKMGR.INI sets WinPresent= to OFF
SeeAlso: AX=1605h,AX=1609h
--------W-2F1607-----------------------------
INT 2F - MS Windows - VIRTUAL DEVICE CALL OUT API
    AX = 1607h
    BX = virtual device ID (see #1968)
    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=1607h/BX=0018h,AX=1684h"DEVICE API",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
SeeAlso: AX=1607h"CALL OUT API"
--------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-2F1607BX000D-----------------------
INT 2F C - MS Windows95 - "VKD" VIRTUAL DEVICE - ??? CALLOUT
    AX = 1607h
    BX = 000Dh (VxD ID for VKD)
    ???
Return: ???
SeeAlso: AX=1607h"CALL OUT API",#1968
--------W-2F1607BX0010-----------------------
INT 2F C - MS Windows 3.1 - "BLOCKDEV" VIRTUAL HARD DISK DEVICE API
    AX = 1607h
    BX = 0010h (VxD identifier of "BLOCKDEV")
    CX = function
        0001h starting FastDisk compatibility tests
        0002h ending FastDisk compatibility tests
        0003h check if FastDisk installation allowed
        Return: CX = 0000h if allowed
Note:    this interface is called by the Windows FastDisk driver (such as
      WDCTRL) when it thinks that the INT 13h handler immediately below
      IO.SYS's INT 13h code is not in ROM; it should be supported by any
      program which hooks itself underneath IO.SYS's INT 13h code with
      INT 2F/AH=13h
SeeAlso: AX=1607h/BX=0014h,INT 2F/AH=13h
--------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 #1963)
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=0010h,AX=1607h/BX=0015h

(Table 1963)
Values for VNETBIOS 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 C - 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 #1965)
        0001h set patches in DOS
        DX = bit mask of patch requests (see #1964)
        Return: AX = B97Ch
            BX = bit mask of patches applied (see #1964)
            DX = A2ABh
        0002h remove patches in DOS (ignored by DOS 5.0 kernel)
        DX = bit mask of patch requests (see #1964)
        Return: CX = 0000h (DOS 5-6)
        Note:    return values are ignored by DOSMGR in Windows 3.1
        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:
                CX = 0000h
                all other 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
SeeAlso: AX=1684h"DEVICE API"

Bitfields for DOSMGR patch requests:
Bit(s)    Description    (Table 1964)
 0    enable critical sections
 1    NOP setting/checking user ID
 2    turn INT 21/AH=3Fh on STDIN into polling loop
 3    trap stack fault in "SYSINIT" to WIN386
 4    BIOS patch to trap "Insert disk X:" to WIN386

Format of DOSMGR patch table:
Offset    Size    Description    (Table 1965)
 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
--------W-2F1607BX0018-----------------------
INT 2F C - MS Windows - "VMPoll" VIRTUAL DEVICE - IDLE CALLOUT
    AX = 1607h
    BX = 0018h (VMPoll VxD ID) (see #1968)
    CX = 0000h
Return: AX = status
        0000h if timeslice used
        nonzero if timeslice not needed
Note:    when VMPoll makes this callout, all virtual machines are idle
SeeAlso: AX=1607h"CALL OUT API"
--------W-2F1607BX0021--------------------------------------
INT 2F C - MS Windows - "PageFile" VIRTUAL DEVICE - GET LOCK BYTE
    AX = 1607h
    BX = 0021h (PageFile VxD ID)
    CX = 0000h
Return: AX = status
        0000h success
        ES:DI -> cache lock byte in disk cacher
        other no disk cache or unsupported
Notes:    PageFile issues this call on real-mode initialization in order to allow
      disk caches to provide it with a byte which it can use to temporarily
      lock the disk cache; VMPOLL also issues this call, so it is made
      twice each time Windows starts up
    if this call fails, PageFile falls back to other techniques for locking
      the disk cache
SeeAlso: AX=1607h"CALL OUT API"
--------W-2F1607BX002D-----------------------
INT 2F C - MS Windows - "W32S" VIRTUAL DEVICE - ??? CALLOUT
    AX = 1607h
    BX = 002Dh (VxD ID for W32S)
    ???
Return: ???
SeeAlso: AX=1607h"CALL OUT API",#1968
--------W-2F1607BX0040-----------------------
INT 2F C - MS Windows - "IFSMgr" VIRTUAL DEVICE - ??? CALLOUT
    AX = 1607h
    BX = 0040h (VxD ID for IFSMgr)
    ???
Return: ???
SeeAlso: AX=1607h"CALL OUT API",#1968
--------W-2F1607BX0446-----------------------
INT 2F C - MS Windows - "VADLIBD" VIRTUAL DEVICE - ??? CALLOUT
    AX = 1607h
    BX = 0446h (VxD ID for VADLIBD)
    ???
Return: ???
SeeAlso: AX=1607h"CALL OUT API",#1968
--------W-2F1607BX0484-----------------------
INT 2F C - MS Windows - "IFSMgr" VIRTUAL DEVICE - ??? CALLOUT
    AX = 1607h
    BX = 0484h (VxD ID for IFSMgr)
    ???
Return: ???
SeeAlso: AX=1607h"CALL OUT API",#1968
--------W-2F1607BX0487-----------------------
INT 2F C - MS Windows - "NWSUP" VIRTUAL DEVICE - ??? CALLOUT
    AX = 1607h
    BX = 0487h (VxD ID for NWSUP)
    ???
Return: ???
SeeAlso: AX=1607h"CALL OUT API",#1968
--------E-2F1607BX22C0-----------------------
INT 2F C - Rational Systems DOS/4GW - ???
    AX = 1607h
    BX = 22C0h
    ???
Return: ???
SeeAlso: INT 15/AX=BF02h,INT 15/AX=BF04h,#1968
--------W-2F1607BX28A1-----------------------
INT 2F C - MS Windows - "PharLap" VIRTUAL DEVICE - ??? CALLOUT
    AX = 1607h
    BX = 28A1h (VxD ID for PharLap)
    ???
Return: ???
SeeAlso: AX=1607h"CALL OUT API",#1968
--------W-2F1607BX7A5F-----------------------
INT 2F C - MS Windows - "SIWVID" VIRTUAL DEVICE - ??? CALLOUT
    AX = 1607h
    BX = 7A5Fh (VxD ID for SIWVID)
    ???
Return: ???
SeeAlso: AX=1607h"CALL OUT API",#1968
--------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 #1966) 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    (Table 1966)
 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 #1967)
 18h    DWORD    pointer to TSR data block or 0000h:0000h

Format of Norton Utilities 6.0 TSR ID block:
Offset    Size    Description    (Table 1967)
 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; appears to be a NOP under standard Windows95
SeeAlso: AX=160Bh
--------D-2F160E-----------------------------
INT 2F U - MS-DOS 7 kernel - BOOT LOGO SUPPORT???
    AX = 160Eh
    BL = subfunction
        00h get ???
        AX = state of flag manipulated by subfn 04h and 05h
            0000h clear
            FFFFh set
        DX = ??? (0000h)
        01h link in INT 10h??? handlers
        02h unlink INT 10h??? handlers
        03h ???
        04h set ??? flag
        05h clear ??? flag
Return: AX = 0000h if supported
        ???
SeeAlso: AX=160Fh,AX=1611h,AX=1614h
--------D-2F160F-----------------------------
INT 2F U - MS-DOS 7 kernel - GET/SET ??? HANDLER
    AX = 160Fh
    BL = subfunction
        00h get ??? handler
        Return: AX = 0000h if supported
                CX:DX -> handler to which control is passed after
                      ??? executes
        01h set ??? handler
        CX:DX -> new handler for ???
        Return: AX = 0000h if supported
Notes:    this function is not supported if ??? in the IO.SYS drivers portion of
      the kernel is an IRET instruction (as is the case on my system)
      rather than a FAR JMP
    the indicated handler seems to be related to INT 10 processing
SeeAlso: AX=160Eh,AX=1611h,AX=1614h
--------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
--------D-2F1611-----------------------------
INT 2F U - MS-DOS 7 kernel - GET SHELL PARAMETERS
    AX = 1611h
Return: AX = 0000h if supported
        DS:DX -> primary shell's executable name
        DS:SI -> prinary shell command line (counted string)
        BH = ??? (00h)
        BL = ??? (00h)
Desc:    return the program name and commandline from the CONFIG.SYS SHELL=
      statement
SeeAlso: AX=160Eh,AX=160Fh,AX=1612h,AX=4A33h
--------D-2F1612-----------------------------
INT 2F U - MS-DOS 7 kernel - GET ???
    AX = 1612h
Return: AX = 0000h if supported
        ES:BX -> ??? data
Note:    called by VTD.VXD
SeeAlso: AX=160Fh,AX=1611h,AX=1613h
--------D-2F1613-----------------------------
INT 2F - MS-DOS 7 kernel - GET SYSTEM.DAT (REGISTRY FILE) PATHNAME
    AX = 1613h
    ES:DI -> buffer for full ASCIZ pathname to Windows95 SYSTEM.DAT
    CX = buffer size in bytes
Return: AX = 0000h if supported
        ES:DI buffer filled
        CX = number of bytes copied into buffer
SeeAlso: AX=160Eh,AX=1611h,AX=1612h,AX=1614h,AX=1690h
--------D-2F1614-----------------------------
INT 2F U - MS-DOS 7 kernel - SET SYSTEM.DAT (REGISTRY FILE) PATHNAME
    AX = 1614h
    ES:DI -> ASCIZ pathname to Windows95 SYSTEM.DAT
Return: AX = status
        0000h if successful
        1614h not supported
        other: maximum length of pathname (004Eh for v4.00.950)
SeeAlso: AX=160Eh,AX=1611h,AX=1613h,AX=1690h
----------2F1615-----------------------------
INT 2F - Windows95 - SAVE32.COM - INSTALLATION CHECK
    AX = 1615h
Return: AX = 0000h if installed
        BX = segment of resident code
Program: SAVE32.COM is a TSR included in the Windows95 distribution which
      preserves the contents of 32-bit registers across invocations of
      all of the hardware interrupt handlers (which, for some older BIOSes
      and TSRs, do not properly preserve the high words of the 32-bit
      registers)
--------W-2F1680-----------------------------
INT 2F - MS Windows, DPMI, various - RELEASE CURRENT VIRTUAL MACHINE TIME-SLICE
    AX = 1680h
Return: AL = status
        00h if the call is supported
        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+, DOS 5+,
      DPMI 1.0+, and 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
    when called very often without intermediate screen output under
      MS Windows 3.x, the VM will go into an idle-state and will not
      receive the next slice before 8 seconds have elapsed. This time can
      be changed in SYSTEM.INI through "IdleVMWakeUpTime=<seconds>".
      Setting it to zero results in a long wait.
    this function has no effect under OS/2 2.10-4.0 if the DOS box has an
      "Idle Sensitivity" setting of 100
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"DEVICE API",AX=1685h,AX=168Bh
--------W-2F1684-----------------------------
INT 2F - MS Windows - GET DEVICE API ENTRY POINT
    AX = 1684h
    BX = virtual device (VxD) ID (see #1968)
    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=1684h/BX=0001h,AX=1684h/BX=0015h,AX=1683h,AX=4011h,INT 20"Windows"

(Table 1968)
Values for MS Windows VxD ID:
Value    Name   CallOut V86 PM    Description
 0000h    ACT200L            IrDA Infrared ActiSys framer VxD
 0000h    ACT220L            IrDA Infrared ActiSys 220 framer VxD
 0000h    ADAPTEC            IrDA Infrared Adaptec framer VxD
 0000h    AM1500T        N  N    (Win95)
 0000h    ATI        N  N    (Win95) ATI display driver
 0000h    CDFS        N  N
 0000h    CDTSD        N  N    (Win95) CD-ROM Type-Specific Driver
 0000h    CE2NDIS3    N  N    (W4Wg)
 0000h    CENDIS        N  N    (W4Wg)
 0000h    CHIPS        N  N    (Win95) Chips&Tech display driver
 0000h    CIRRUS        N  N    (Win95) Cirrus display driver
 0000h    CTNDW        N  N    (W4Wg)
 0000h    CTVSD        N  N    (Win95) CD-ROM Vendor-Specific Driver
 0000h    CM2NDIS3    N  N    (W4Wg)
 0000h    COMBUFF        N  N    (Win95)
 0000h    COMPAQ        N  N    (Win95) Compaq display driver
 0000h    CPQNDIS3    N  N    (W4Wg)
 0000h    CRYSTAL            IrDA Infrared Crystal framer VxD
 0000h    DBKVSSD        N  N    (Win95) Databook PCMCIA socket services???
 0000h    DDOM95        N  N
 0000h    DECLAN        N  N    (W4Wg)
 0000h    DiskTSD        N  N    (Win95) hard-disk Type-Specific Driver
 0000h    DiskVSD        N  N    (Win95) hard-disk Vendor-Specific Driver
 0000h    DMICTVXD    N  N
 0000h    DRVSPACX    N  N    (Win95)
 0000h    E30N3        N  N    (W4Wg)
 0000h    E31N3        N  N    (W4Wg)
 0000h    EE16        N  N    (W4Wg)
 0000h    EISA        N  N    (Win95)
 0000h    EL59X        N  N    (Win95)
 0000h    ELNK16        N  N    (W4Wg)
 0000h    ELNK3        N  N    (Win95)
 0000h    ELNKII        N  N    (W4Wg)
 0000h    ELNKMC        N  N    (W4Wg)
 0000h    ELPC3        N  N    (W4Wg)
 0000h    ENABLE2        N  N    (Win95)
 0000h    ENABLE4        N  N    (Win95)
 0000h    EPRO        N  N    (Win95)
 0000h    ES1488V        N  N    (Win95)
 0000h    ES1688V        N  N    (Win95)
 0000h    ES488V        N  N    (Win95)
 0000h    ES688V        N  N    (Win95)
 0000h    ESI            IrDA Infrared ESI framer VxD
 0000h    FILEMON        N  N    DOS386 File Monitor
 0000h    FLS1MTD        N  N    (Win95) flash-memory driver???
 0000h    FLS2MTD        N  N    (Win95) flash-memory driver???
 0000h    HPEISA        N  N    (W4Wg)
 0000h    HPFEND        N  N    (W4Wg)
 0000h    HPISA        N  N    (W4Wg)
 0000h    HPMCA        N  N    (W4Wg)
 0000h    HSFLOP        N  N
 0000h    IBMTOK        N  N    (W4Wg)
 0000h    IBMTOK4        N  N    (Win95)
 0000h    IRCOMM            IrDA Infrared Virtual COM/LPT driver
 0000h    IRLAMPEX        IrDA Infrared Protocol VxD
 0000h    IRLAPFRM        IrDA Infrared Virtual COM/LPT frame driver
 0000h    IRMATRAK    N  N    (W4Wg)
 0000h    JAVASUP        N  N    Internet Explorer JAVA support
 0000h    KEYREMAP    N  N    (Windows95 PowerToys) shift-key remapper
 0000h    LPT         N    N  N    (Win4Workgroups 3.11) DOS386 LPT Device
 0000h    LPTENUM        N  N
 0000h    MONVSD
 0000h    MGA        N  N    (Win95) Matrox MGA display driver
 0000h    MSMINI        N  N    (Win95)
 0000h    MSODISUP     N    N  N    (Win4Workgroups 3.11) MS ODI Support
 0000h    mvpas        N  N    (Win95) Pro Audio Spectrum driver
 0000h    NECATAPI    N  N    (Win95)
 0000h    NICE        N  N    (Win95)
 0000h    NWNBLINK     N    N  N    (Win4Workgroups 3.11) Netware NetBIOS
 0000h    OAK        N  N    (Win95) Oak Tech display driver
 0000h    OCTK32        N  N    (W4Wg)
 0000h    OTCETH        N  N    (W4Wg)
 0000h    PARALINK    N  N    (Win95)
 0000h    PARALLAX        IrDA Infrared Parallax framer VxD
 0000h    PCNTN3        N  N    (W4Wg)
 0000h    PE3NDIS        N  N    (W4Wg)
 0000h    PPM        N  N    (Win95)
 0000h    PROTEON        N  N    (W4Wg)
 0000h    QEMMFix        N  N
 0000h    QIC117        N  N    (Win95) QIC-117 floppy-ctrl tape drive
 0000h    QPI        N  N    QEMM Programming Interface (see INT 67/AH=3Fh)
 0000h    RMM        N  N    Real-Mode Mapper for hw with real-mode drivers
 0000h    S3        N  N    (Win95) S3 display driver
 0000h    S3INFO        N  N
 0000h    S3MINI        N  N    S3 display driver
 0000h    SAGE        N  N    (Plus!) System Agent
 0000h    scsi1hlp    N  N    (Win95)
 0000h    SERENUM        N  N
 0000h    SERIAL         N    N  N    (Win4Workgroups 3.11) DOS386 Serial Device
 0000h    SERWAVE        N  N
 0000h    SETP3        N  N    (Win95) Silicon Ethernet Pocket Adapter
 0000h    SMC8000W    N  N    (W4Wg)
 0000h    SMC80PC        N  N    (W4Wg)
 0000h    SMC8100W    N  N    (W4Wg)
 0000h    SMC8232W    N  N    (W4Wg)
 0000h    SMC9000        N  N    (W4Wg)
 0000h    SNIP        N  N    (W4Wg)
 0000h    SOCKET        N  N    (W4Wg)
 0000h    SOCKETSV    N  N    (Win95)
 0000h    SPAP        Y  Y    (Win95)
 0000h    SPENDIS        N  N    (Win95)
 0000h    SRAMMTD        N  N    (Win95) flash-memory driver???
 0000h    STLTH64        N  N    Diamond Stealth64 driver
 0000h    STLTHMON    N  N
 0000h    T20N3        N  N    (W4Wg)
 0000h    T30N3        N  N    (W4Wg)
 0000h    TCTOK        N  N    (W4Wg)
 0000h    TSENG        N  N    (Win95) Tseng Labs display driver
 0000h    UBNEI        N  N    (W4Wg)
 0000h    UNIMODEM        (Win95) Universal Modem Driver
 0000h    VDEF        N  N    (Win95)
 0000h    VGATEWAY    N  Y    (Win95) dialin gateway
 0000h    VIDEO7        N  N    (Win95) Video7 display driver
 0000h    VRomD        N  N    (Win95)
 0000h    VStDspcD        Quarterdeck Stealth D*Space
 0000h    VXDMON
 0000h    WD        N  N    (Win95)
 0000h    WINTOP        N  N    (Windows95 Power Toys)
 0000h    WSHTCP        N  N
 0000h    XGA        N  N    (Win95) XGA display driver
 0001h    VMM        N  N    Virtual Machine Manager
 0001h    VMM        Y  Y    Windows95 Virtual Machine Manager
 0002h    Debug
 0003h    VPICD        Y  Y    Virtual Prog. Interrupt Controller (PIC) Device
 0004h    VDMAD        N  N    Virtual Direct Memory Access (DMA) Device
 0005h    VTD        Y  Y    Virtual Timer Device
 0006h    V86MMGR         Y    N  N    (Windows3.x) Virtual 8086 Mode Device
 0006h    V86MMGR        N  Y    (Win95) Virtual 8068 Mode Device
 0007h    PageSwap    N  N    Paging Device
 0008h    Parity        N  N    Parity-check trapper
 0009h    Reboot        N  Y    Ctrl-Alt-Del handler
 000Ah    VDD        N  Y    Virtual Display Device (GRABBER)
 000Bh    VSD        N  N    Virtual Sound Device
 000Ch    VMD         Y    Y  Y    Virtual Mouse Device
 000Dh    VKD        N  Y    Virtual Keyboard Device
 000Eh    VCD        N  Y    Virtual COMM Device
 000Fh    VPD        N  Y    Virtual Printer Device
 0010h    VHD            Virtual Hard Disk Device (Windows 3.0)
 0010h    BLOCKDEV     Y    N  N    Virtual Hard Disk Device (Windows 3.1)
 0010h    IOS         N    N  N    (Win4Workgroups 3.11) DOS386 IOS Device
 0010h    IOS        Y  Y    Windows95 I/O Supervisor
 0011h    VMCPD        Y  Y    (Windows3.x) Virtual Math CoProcessor Device
 0011h    VMCPD        N  Y    (Win95) Virtual Math CoProcessor Device
 0012h    EBIOS        N  N    Reserve EBIOS page (e.g., on PS/2)
 0013h    BIOSXLAT    N  N    Map ROM BIOS API between prot & V86 mode
 0014h    VNETBIOS     Y    N  N    Virtual NetBIOS Device
 0015h    DOSMGR         Y    Y  N    DOS data instancing (see #1971)
 0016h    WINLOAD
 0017h    SHELL        N  Y    (Windows3)
 0017h    SHELL        Y  Y    (Win95)
 0018h    VMPOLL         Y    N  N
 0019h    VPROD
 001Ah    DOSNET        N  N    assures network integrity across VMs
 001Ah    VNETWARE    Y  Y    Novell NetWare DOSNET replacement
 001Bh    VFD        N  N    Virtual Floppy Device
 001Ch    VDD2            Secondary display adapter
 001Ch    LoadHi        N  N    Netroom LoadHi Device (RMLODHI.VXD)
 001Ch    LoadHi        N  N    386MAX LoadHi Device (386MAX.VXD)
 001Ch    LoadHi        N  N    Win386 LoadHi Device (EMM386.EXE)
 001Dh    WINDEBUG    N  Y
 001Dh    TDDebug        N  Y
 001Eh    TSRLoad            TSR instance utility
 001Fh    BiosHook        BIOS interrupt hooker VxD
 0020h    Int13         N    N  N
 0021h    PageFile     Y    N  Y    Paging File device
 0022h    SCSI
 0022h    APIX        N  Y    (Win95)
 0023h    MCA_POS            Microchannel Programmable Option Select
 0024h    SCSIFD            SCSI FastDisk device
 0025h    VPEND            Pen device
 0026h    APM            Advanced Power Management
 0026h    VPOWERD        Y  Y    (Win95) power management
 0027h    VXDLDR         N    Y  Y    (Win4Wg 3.11/Win95) VXD Loader
 0028h    NDIS         N    Y  Y    (Win4Wg 3.11) Network Driver Interface Spec
 0029h    ???
 002Ah    VWIN32        N  Y    (Win95)
 002Bh    VCOMM         N    Y  Y    (Win4Workgroups 3.11) DOS386 VCOMM Device
 002Ch    SPOOLER        N  N    Windows95 print spooler
 002Dh    W32S         Y    N  Y    WIN32s 32-bit extension to Windows API
 002Eh    ???
 002Fh    ???
 0030h    MACH32         N    N  Y    ATI Mach32 video card
 0031h    NETBEUI         N    N  N    (Win4Workgroups 3.11) NETBEUI
 0032h    SERVER         N    Y  Y    (Win4Workgroups 3.11) Int21 File Server
 0032h    VSERVER        N  Y    (Win95) Int21 File Server
 0033h    CONFIGMG    Y  Y    (Win95)
 0033h    EDOS        N  N    Windows DOS Box Enhancer by Mom's Software
 0034h    DWCFGMG.SYS    Y    DOS Plug-and-Play configuration manager
 0035h    SCSIPORT    N  N    (Win95) virtualized access to SCSI adapter
 0036h    VFBACKUP    Y  Y    (Win95)
 0037h    ENABLE        Y  Y    (Win95)
 0038h    VCOND        Y  Y    (Win95)
 0039h    ???
 003Ah    VPMTD         N    N  Y    (Win4Workgroups 3.11) IFAX Scheduler Device
 003Bh    DSVXD        Y  N    DoubleSpace VxD from MS-DOS v6.x
 003Ch    ISAPNP        N  N    (Win95)
 003Dh    BIOS        Y  Y    (Win95)
 003Eh    WSOCK        Y  Y    (Win95) WinSock
 003Fh    WSIPX        N  N    (Win95) IPX WinSock
 0040h    IFSMGR        N  N    (Win95)
 0041h    VCDFSD        N  N    (Win95) CD-ROM File System Driver (MSCDEX)
 0042h    MRCI2        N  N    (Win95) DriveSpace3
 0043h    PCI        N  N    (Win95)
 0048h    PERF        N  N    (Win95)
 0051h    ISAPNP        N  N    (Win95) ISA Plug-and-Play manager
 008Dh    ESDI_506    N  N    (Win95) MFM/RLL/ESDI disk driver
 0090h    voltrack    N  N    (Win95) Volume Tracker
 00FDh    FAKEIDE        N  N    (Chicago)
 0102h    CV1        N  N    Microsoft C/C++ 7.00+ CodeView for Windows
 011Fh    VFLATD        N  Y    (Win95)
 0200h    VIPX        Y  Y    NetWare Virtual IPX Driver
 0200h    VTEMPD            dummy template driver by Ray Patch
 0201h    VNWLSERV    N  N    NetWare Lite 1.1 Server (SERVER.EXE)
 0202h    WINICE        Y  Y    SoftICE/W
 0202h    SICE        Y  Y
 0203h    VCLIENT        N  Y    NetWare Lite 1.1+ Client
 0205h    VCAFT        N  N    Novell Virtual CAFT Driver (LANalyzer for Win)
 0205h    BCW        Y  Y    Nu-Mega Bounds Checker for Windows
 0206h    VTXRX        N  N    Novell Virtual TXRX Driver (LANalyzer for Win)
 0207h    DPMS         N    Y  N    Novell DOS Protected Mode Services
 0234h    VCOMMUTE    Y  Y    PC Tools Commute
 0442h    VTDAPI        N  Y    MMSys Win386 VTAPI Device
 0443h    ???
 0444h    VADMAD            Autoinitialize DMA (Windows 3.0)
 0445h    VSBD        Y  Y    WinResKit: Sound Blaster Device
 0446h    VADLIBD         Y    Y  Y    MMSys Win386 AdLib Device (v3.x)
 0447h    ???
 0448h    SETULTRA        Gravis UltraSound setup
 0449h    vjoyd        N  Y    (Win95) joystick
 044Ah    mmdevldr    Y  Y    (Win95)
 044Bh    ???
 044Ch    msmpu401    N  N    (Win95) MPU-401 MIDI driver
 044Dh    msopl        N  N    (Win95) OPL-3 (SoundBlaster FM) driver
 044Eh    mssblst        N  N    (Win95) SoundBlaster MIDI driver
 045Dh    VflatD        N  Y    dva.386, part of WIN32s
 045Eh    ???
 045Fh    mssndsys        Microsoft Sound System audio driver
 045Fh    azt16        Y  Y    Aztech Sound Galaxy 16 audio driver
 0460h    UNIMODEM    N  Y    Universal Modem driver
 0480h    VNetSup         N    Y  Y    (Win4Workgrps 3.11) Virtual Network Support
 0481h    VRedir         N    N  N    (Win4Workgroups 3.11) Redirector File System
 0481h    VREDIR        N  N    (Win95) Redirector File System driver
 0482h    VBrowse        Y  Y    Win386 Virtual Browser
 0482h    SNAPVXD        Y  Y    (Win95)
 0483h    VSHARE        N  N    (Win4Workgroups) Virtual SHARE
 0483h    VSHARE        Y  Y    (Win95) Virtual SHARE
 0484h    IFSMgr         Y    N  Y    (Win4Wg 3.11) Installable File System Manager
 0485h    ???            ???
 0486h    VFAT         N    Y  Y    (Win4Workgroups 3.11) Win386 HPFS Driver
 0487h    NWLINK        Y  Y    Win386 Virtual Packet Exchange Protocol
 0487h    NWSUP         Y    N  N    NetWare Vnetbios shim
 0488h    VTDI        N  N    (Win95)
 0489h    VIP        Y  N    (Win95)
 048Ah    VTCP        Y
 048Ah    MSTCP        Y  N    (Win95) TCP stack
 048Bh    VCache         N    Y  Y    (Win4Workgroups 3.11) Virtual File Cache
 048Bh    VCACHE        Y  Y    (Win95) disk cache
 048Ch    ???            ???
 048Dh    RASMAC        Y  Y    enhanced mode Win4Workgroups RASMAC device
 048Eh    NWREDIR        Y  Y    (Win95)
 048Fh    ???            ???
 0490h    ???            ???
 0491h    FILESEC            (Win95) File Access Control Manager
 0492h    NWSERVER        (Win95)
 0493h    SECPROV            (Win95) Security Provider
 0494h    NSCL        Y  Y    (Win95)
 0495h    AFVXD        N  N    (Win95)
 0496h    NDIS2SUP        (W4Wg???)
 0497h    MSODISUP    N  N    (W4Wg???)
 0498h    Splitter    N  N    (Win95)
 0499h    PPPMAC        Y  Y    (Win95)
 049Ah    VDHCP        Y  Y    (Win95)
 049Bh    VNBT        Y  Y    (Win95) NetBIOS-over-TCP/IP driver
 049Ch    ???
 049Dh    LOGGER            (Win95)
 04A2h    IRLAMP            IrDA Infrared Enumerator VxD
 097Ch    PCCARD        N  Y    (Win95)
 1020h    VCV            Microsoft C/C++ 7.00 CodeView
 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
 2020h    PIPE        Y  Y    by Thomas W. Olson, in Windows/DOS DevJrn 5/92
 21EAh    VADLIBWD    N  Y    Adlib Waveform Driver by John Ridges
 2200h    VFINTD        Y  Y    Norton VFINTD (Norton Desktop)
 22C0h    ???         Y        Rational Systems DOS/4GW ???
 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)
 24A2h    SYMEvent    Y  Y    Norton Utilities v8
 2540h    VILD        Y  N    INTERLNK client from MS-DOS v6.x
 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
 28A0h    PHARLAPX    Y    PharLap inter-VM communications DLL
 28A1h    PharLap         Y    Y  Y    PharLap 386|DOS-Extender DOSXNT.386
 28C0h    VXD         N    Y  Y    Generic VxD for real and protected mode by
                  Andrew Schulman in MSJ February 1993
 28C1h    PUSHKEYS        VKD_Force_Keys device
 28C2h    VCR3D            Virtual CR3, by A.Schulman in MSJ October 1992
 2925h    EDOS        Y  Y    Enhanced DOS by Firefly Software
 292Dh    VSBPD        Y  Y    Sound Blaster Pro
 295Ah    GRVSULTR    Y  Y    Gravis UltraSound / UltraSound ACE
 304Ch    DWCFGMG.SYS    Y    Plug-and-Play configuration access
 3098h    VstlthD         N    N  N    for QEMM Stealth ROM mode
 3099h    VVidramD    Y  N    for QEMM VIDRAM support
 30F6h    WSVV        N  Y    (Win95) WinSock for Voice-View Modems???
 310Eh    WPS        N  Y    MS DevNet CD-ROM: Windows Process Status
 313Bh    PMC            Power Management Coordinator
 318Ah    LMOUSE        Y  Y    (Win95) Logitech mouse???
 31CFh    STAT.386        Ton Plooy's processor statistics VxD
 3202h    VdspD        N  N    (Win95)
 3203h    vpasd        N  N    (Win95) Pro Audio Spectrum driver
 32A4h    SBAWE        Y  Y    (Win95) SoundBlaster AWE driver
 32A5h    VSB16        N  N    (Win95) SoundBlaster 16 driver
 32CBh    VFRAD        Y  Y    Dr.Franz - Simultan's diagnotics VFRAD.386
 33AAh    DECCORE        Y  Y    (Win95) DEC Pathworks core VxD
 33B4h    DECLICL        N  N    (Win95)
 33F0h    VIWD        Y  Y    Gravis UltraSound Plug-n-Play Interwave v1.x
 33FCh    ASPIENUM    N  N    (Win95)
 34DCh    MAGNARAM    N  Y    Quarterdeck MagnaRAM (MAGNA31.VXD/MAGNA95.VXD)
 357Eh    DSOUND        Y  Y    (Win95) DirectSound
 36AEh    AIB-PC.386    Y  Y    Sunset Laboratory interface hardware driver
 377Bh    MX1501HAD        Cherry keyboard chipcard reader
 38DAh    VIWD        Y  Y    UltraSond PnP InterWave driver v2.0beta
 4321h    POSTMSG        Y  Y    (see #1996)
 4321h    VPCD        N  N    PCache
 4321h    avvxp500    N  N    (Win95) VxP500 driver
 6001h    REGVXD        Y  Y    Windows95 Registry Monitor helper
 7A5Fh    SIWVID         Y    Y  Y    Soft-ICE for Windows video driver
 7FE0h    VSWITCHD    Y  N    by Jeff Prosise
 7FE0h    VWFD         N    Y  Y    reports windowed/fullscreen state; by Neil
                  Sandlin of Microsoft, shipped with ANSIPLUS
 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
 7FE8h    VPOSTD        Y  Y    PostMessage() demo by Curtis J. Palmer of MS
 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
 8888h    VbillD            Bill Potvin II's for reversing Compaq LTE video
 EEEEh    VEPSD        N  N    Virtual Extended Paging Services for
                  Borland C++ v4.0
Notes:    The high bit of the VxD ID is reserved for future use. Originally,
      the next 10 bits were the OEM number which was assigned by Microsoft,
      and the low 5 bits were the device number.  Currently, Microsoft
      assigns VxD IDs individually for each driver; send blank email to
      [e-mail] for more information.
    "CallOut"=Y indicates that the VxD uses the INT 2F/AX=1607h/BX=VxDID
      device callout interface; "PM" and "V86" indicate whether the VxD
      provides an API entry point in protected mode and Virtual-86 mode
      (e.g. DOS boxes)
--------W-2F1684BX0001-----------------------
INT 2F - MS Windows 95 - VMM - GET API ENTRY POINT
    AX = 1684h
    BX = 0001h (virtual device ID for VMM) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3321)
          0000h:0000h if the VxD does not support an API
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3321)
Call Windows VMM 16-bit entry point with:
    AX = function number
        ---registry functions---
        0100h "RegOpenKey"
        STACK:    DWORD    -> DWORD for returned key handle
            DWORD    -> ASCIZ registry key name
            DWORD    HKEY (see #3322)
        0101h "RegCreateKey"
        STACK:    DWORD    -> DWORD for returned key handle
            DWORD    -> ASCIZ registry key name
            DWORD    HKEY (see #3322)
        0102h "RegCloseKey"
        STACK:    DWORD    key handle from RegOpenKey or RegCreateKey
        0103h "RegDeleteKey"
        STACK:    DWORD    -> ASCIZ registry key name
            DWORD    HKEY (see #3322)
        0104h "RegSetValue"
        STACK:    DWORD    ???
            DWORD    -> ???
            DWORD    ???
            DWORD    -> ???
            DWORD    HKEY (see #3322)
        0105h "RegQueryValue"
        STACK:    DWORD    -> DWORD for ???
            DWORD    -> ASCIZ ???
            DWORD    -> ASCIZ ???
            DWORD    HKEY (see #3322)
        0106h "RegEnumKey"
        STACK:    DWORD    ???
            DWORD    -> ASCIZ ???
            DWORD    ???
            DWORD    HKEY (see #3322)
        0107h "RegDeleteValue"
        0108h "RegEnumValue"
        STACK:    DWORD    -> DWORD for ???
            DWORD    -> BYTE ???
            DWORD    -> DWORD for ???
            DWORD    -> DWORD for ???
            DWORD    -> DWORD for ???
            DWORD    -> ASCIZ ???
            DWORD    ???
            DWORD    HKEY (see #3322)
        0109h "RegQueryValueEx"
        010Ah "RegSetValueEx"
        010Bh "RegFlushKey"
        010Ch "RegLoadKey"
        010Dh "RegUnLoadKey"
        010Eh "RegSaveKey"
        010Fh "RegRestore"
        0110h "RegRemapPreDefKey"
Return: parameters popped from stack
    DX:AX = return value

(Table 3322)
Values for Windows95 VMM predefined HKEY values:
 80000000h    HKEY_CLASSES_ROOT
 80000001h    HKEY_CURRENT_USER
 80000002h    HKEY_LOCAL_MACHINE
 80000003h    HKEY_USERS
 80000004h    HKEY_PERFORMANCE_DATA
 80000005h    HKEY_CURRENT_CONFIG
 80000006h    HKEY_DYN_DATA
SeeAlso: #3321
--------W-2F1684BX0003-----------------------
INT 2F - MS Windows - VPICD - GET API ENTRY POINT
    AX = 1684h
    BX = 0003h (virtual device ID for VPICD device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3467)
          0000h:0000h if the VxD does not support an API
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3467)
Call VPICD API entry point with:
    EAX = function number
        0000h get version
        Return: AX = binary version (AH=major, AL=minor)
        0001h virtualize timer???
        0002h unvirtualize timer???
--------W-2F1684BX0005-----------------------
INT 2F - MS Windows - VTD - GET API ENTRY POINT
    AX = 1684h
    BX = 0005h (virtual device ID for VTD device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #1969)
          0000h:0000h if the VxD does not support an API
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 1969)
Call VTD.386/VTD.VXD entry point with:
    AX = function number
        0000h get VTD version number
        Return: CF clear
            AH = major version
            AL = minor version
        0100h get current clock tick time
        Return: EDX:EAX = clock tick time in 840ns units since Windows
                  was started
        0101h get current system time in milliseconds
        Return: EAX = time in milliseconds that Windows has been
                  running
        0102h get current virtual machine time
        Return: EAX = cumulative amount of time the virtual machine has
                  been active, in milliseconds
Note:    this entry point should only be called directly when TOOLHELP.DLL
      TimerCount() cannot be called
SeeAlso: #0674,#0676,#0675 at INT 20"Windows"
--------W-2F1684BX0006-----------------------
INT 2F P - MS Windows95 - V86MMGR - GET API ENTRY POINT
    AX = 1684h
    BX = 0006h (virtual device ID for V86MMGR device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3468)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3468)
Call V86MMGR entry point with:
    EAX = function number
        0000h get V86MMGR version
        Return: CF clear
            AH = major version
            AL = minor version
        0001h get ???
        Return: CF clear
            EAX = status bits
                bit 0: ???
                bit 1: ???
                bit 2: ???
                bit 3: ???
                bit 4: ???
        else
        Return: CF set
--------W-2F1684BX0009-----------------------
INT 2F P - MS Windows - REBOOT - GET API ENTRY POINT
    AX = 1684h
    BX = 0009h (virtual device ID for REBOOT device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #1970)
          0000h:0000h if the VxD does not support an API
SeeAlso: INT 14/AH=17h"FOSSIL",INT 16/AX=E0FFh

(Table 1970)
Call REBOOT protected-mode entry point with:
    AX = function
        0100h warm boot
        Return: never
        Note:    broadcasts "Reboot_Processor" message, which is caught
              by the VKD device
        0201h set KERNEL Ctrl-Alt-Del handler
        ES:DI -> new Ctrl-Alt-Del handler
        DS:SI -> KERNEL reboot sanity check byte
        Return: CF clear
        Notes:    if an application installs its own handler and then
              chains to Windows' handler, Windows will no longer
              be able to detect hung applications, and will always
              produce an "Application not responding" dialog
            DS must contain a writable, fixed selector because
              the provided address is converted to a linear address
              before being stored
            when Ctrl-Alt-Del is pressed in the system VM, Reboot
              sets the sanity check byte to zero, schedules a
              750ms wait, and then tests whether the check byte is
              still zero; if not, it displays a message that there
              is no hung application and then exits
        0202h get KERNEL Ctrl-Alt-Del handler
        Return: CF clear
            ES:DI -> current Ctrl-Alt-Del handler
        Note:    the default handler is located in KERNEL
        0203h display "Application not responding" dialog box
        ES:DI -> ASCIZ name of hung application
        Return: never if user pressed Ctrl-Alt-Del a second time
            CF clear
            AX = result
                0000h user pressed Esc
                0001h user pressed Enter
        Note:    this function is used by the default Windows
              Ctrl-Alt-Del handler
        0204h set/reset protected-mode INT 01 handler
        CX:EDX -> new protected-mode INT 01 handler
        CX = 0000h restore protected-mode INT 01 handler
        Return: CF clear
        Notes:    if CX is nonzero, the current handler address is saved
              internally before the new handler is set; this saved
              address is then used when CX is zero on entry
            used by Windows' default Ctrl-Alt-Del handler; actual
              fatal exit to DOS will be done on next INT 01
        Warning: opened files are not closed and remain open as
              orphaned files in DOS
Note:    functions 0201h and 0203h are not useful outside the system VM
SeeAlso: #0677,#0678
--------W-2F1684BX000A-----------------------
INT 2F P - MS Windows - VDD - GET API ENTRY POINT
    AX = 1684h
    BX = 000Ah (virtual device ID for VDD device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3469)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3469)
Call VDD entry point with:
    EAX = function
        0000h get VDD version
        Return: CF clear
            AH = major version
            AL = minor version
        Note:    also performs an internal initialization
        0001h ???
        Return: ECX = ???
            ???
        0002h
        0003h
        0004h
        0005h
        0006h
        0007h
        0008h
        0009h
        0080h
        0081h
        0082h
        0083h
        0084h
        0085h
        0086h
        0087h
        0088h
        0089h
        else
        Return: nothing
--------W-2F1684BX000C-----------------------
INT 2F - MS Windows - VMD - GET API ENTRY POINT
    AX = 1684h
    BX = 000Ch (virtual device ID for VMD device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3470)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3470)
Call VMOUSE entry point with:
    EAX = function number
        0000h get VMOUSE version
        Return: CF clear
            AH = major version
            AL = minor version
        0001h
        EBX = ???
        ECX = ???
        Return: CF clear if successful
            CF set on error (e.g. fn 0003h not yet called)
        0002h ??? (calls "test system VM handle")
        Return: CF clear if successful (in system VM)
            CF set on error
        0003h ???
        ECX = ???
        DX = ???
        Return: CF clear
        0004h ???
        Note: invokes Call_Priority_VM_Event
        0005h get mouse port data
        Return: CF clear
            AL = ??? (04h)
            AH = mouse IRQ interrupt number (IRQ4=0Ch,etc.)
            CX = mouse I/O port address (e.g. 03F8h)
            DX = COM port number??? (0001h for mouse on COM1)
        0100h NOP???
        Return: CF clear
        0101h init???
        Return: CF clear
        Note:    appears to be the same as fn 0005h, but returns no data
        0102h unimplemented
        Return: CF set
        0103h check ???
        Return: AX = status (0000h/0001h)
        Note:    checks flag set by fn 0003h
        else
        Return: CF set
SeeAlso: #3469,#3471
--------W-2F1684BX000D-----------------------
INT 2F P - MS Windows - VKD - GET API ENTRY POINT
    AX = 1684h
    BX = 000Dh (virtual device ID for VKD device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3471)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3471)
Call VKD entry point with:
    EAX = function
        0000h get VKD version
        Return: CF clear
            AH = major version
            AL = minor version
        0001h ???
        EBX = VM handle or 00000000h to use ??? VM handle
        CH = ???
        CL = ???
        EDX = ??? or FFFFFFFFh
        Return: CF clear if successful
            CF set on error
        else
        Return: CF set
SeeAlso: #3470,#3472
--------W-2F1684BX000E-----------------------
INT 2F P - MS Windows - VCD - GET API ENTRY POINT
    AX = 1684h
    BX = 000Eh (virtual device ID for VCD device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3472)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3472)
Call VCD entry point with:
    EDX = function number
        0000h get VCD version
        Return: CF clear
            AH = major version
            AL = minor version
        0001h get ???
        Return: CF clear
            AX = bit mask of ???
        0002h get ???
        CX = COM port number
        Return: CF clear
            DX:AX -> ???
        0003h set ???
        CX = COM port number
        DX:AX -> new ???
        Return: CF clear
        0004h acquire COM port
        AX = ???
        CX = COM port number
        Return: CF clear
            AX = ???
            EBX = ???
            DX = ???
        0005h release COM port
        CX = COM port number
        Return: CF clear
        0006h ???
        Return: CF set
            AL = 00h
        else
        Return: CF set
            EAX = FFFFFFFFh
Note:    these functions are apparently only available from the system VM,
      returning CF set and EAX=FFFFFFFFh otherwise
SeeAlso: #3471,#3473
--------W-2F1684BX000F-----------------------
INT 2F P - MS Windows - VPD - GET API ENTRY POINT
    AX = 1684h
    BX = 000Fh (virtual device ID for VPD device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3473)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3473)
Call VPD entry point with:
    EDX = function number
        0000h get VPD version
        Return: CF clear
            AH = major version
            AL = minor version
            DX = ??? (CB01h)
        0001h get valid??? printers
        Return: CF clear
            AX = bitmask of ??? printers (bits 0-2)
        0002h get ??? for printer
        CX = printer port (0-2)
        Return: CF clear if successful
                BX:AX = ???
            CF set on error (invalid port number)
        0003h set ??? for printer
        CX = printer port (0-2)
        BX:AX = ???
        Return:    CF clear if successful
            CF set on error (invalid port number)
        0004h ???
        CX = printer port (0-2)
        EAX = VM handle
        Return:    CF clear if successful
            CF set on error (invalid port number)
        0005h ???
        CX = printer port (0-2)
        EAX = VM handle
        Return:    CF clear if successful
            CF set on error (invalid port number or ???)
        0006h-000Eh unused
        Return: CF set
        000Fh ???
        CX = printer port (0-2)
        AX = ???
        Return:    CF clear if successful
            CF set on error (e.g. invalid port number)
        0010h ???
        CX = printer port (0-2)
        Return:    CF clear if successful
            CF set on error (e.g. invalid port number)
        0011h ???
        CX = printer port (0-2)
        Return:    CF clear if successful
            CF set on error (e.g. invalid port number)
        0012h get port status
        CX = printer port (0-2)
        Return:    CF clear if successful
                AX = port status (see #P150 at PORT 03BCh"LPT")
            CF set on error (e.g. invalid port number)
        else
        Return: CF set
Note:    these functions are apparently only available from the system VM,
      returning CF set
SeeAlso: #3472,#3474
--------W-2F1684BX0010-----------------------
INT 2F - MS Windows - IOS - GET API ENTRY POINT
    AX = 1684h
    BX = 0010h (virtual device ID for IOS device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3474)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3474)
Call IOS entry point with:
    EAX = function number
        0000h ???
        Return: CF clear if successful
                AX = 0000h
            CF set on error
                AX = FFFFh
        0001h check if ???
        Return: CF clear if successful
                AX = 0000h
            CF set on error
                AX = FFFFh
        0002h requestor services???
        DL = service number???
        Return: CF clear if successful
                AX = 0000h
                DX = ???
            CF set on error
                AX = FFFFh
        Note:    calls "IOS_Requestor_Service" (see INT 20"Windows")
        0003h ??? (copies five bytes of data internally)
        Return: CF clear if successful
                AX = 0000h
                EDX = ???
            CF set on error
                AX = FFFFh
        else
        Return: CF set
            AX = FFFFh
SeeAlso: #3473,#3475
--------W-2F1684BX0011-----------------------
INT 2F - MS Windows - VMCPD - GET API ENTRY POINT
    AX = 1684h
    BX = 0011h (virtual device ID for VMCPD device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3475)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3475)
Call Windows95 VMCPD protected-mode entry point with:
    EAX = function number
        0000h get VMCPD version
        Return: CF clear
            AH = major version
            AL = minor version
        0001h get ??? flags
        Return: CF clear
            AX = ??? flags
                bit 0: ???
                bit 1: ???
                bit 2: ???
                bit 3: ???
        else
        Return: CF set
SeeAlso: #3474,#1971
--------W-2F1684BX0015-----------------------
INT 2F - MS Windows - DOSMGR - GET API ENTRY POINT
    AX = 1684h
    BX = 0015h (virtual device ID for DOSMGR device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #1971,#0686)
          0000h:0000h if the VxD does not support an API
SeeAlso: #0686 at INT 20"Windows"

(Table 1971)
Call DOSMGR entry point with:
    AX = 0000h get DOSMGR version
        Return: CF clear
            AX = version (AH = major, AL = minor)
    AX = 0001h set critical focus
        Return: CF clear
    AX = 0002h crash current virtual machine
        Return: never
        Note:   displays message box stating that "application has been
              stopped by the DOSMGR device"
    AX = 0003h enter critical section
        Note:   this function assumes that the code for INT 2A/AX=8001h
              and INT 2A/AX=8002h have been modified for Windows
    AX = 0004h get VM ID byte
        Return: CF clear if successful
            ES:DI -> VM ID byte
            CF set on error
        Note:   this function fails if the INT 2A modifications have not
              yet been applied
    AX = 0005h inform Windows of possible media change
        BL = drive number (00h=A:)
        Return: CF clear if successful
            CF set on error
SeeAlso: #0686 at INT 20"Windows",#3475,#1972
--------W-2F1684BX0017-----------------------
INT 2F U - MS Windows - SHELL - GET API ENTRY POINT
    AX = 1684h
    BX = 0017h (virtual device ID for SHELL device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #1972)
          0000h:0000h if the VxD does not support an API
SeeAlso: AX=1684h/BX=0021h,#0687 at INT 20"Windows"

(Table 1972)
Call SHELL entry point with:
    EDX = function number (0000h-0027h,0100h-0108h, mostly unknown)
        0000h get version number
        Return: AX = version number
            EBX = system VM handle
        0001h "SHELL_Get_SYSVM_Info" get system VM information
        Return: CF clear
            AX bit 0 set if system VM executing exclusively
            BX = background time slice priority
            CX = foreground time slice priority
            SI = minimum time slice in milliseconds
        0002h "SHELL_Set_SYSVM_Info" set system VM information
        AX bit 0 set if system VM should execute exclusively (ignored?)
        BX = background time slice priority (1-10000)
        CX = foreground time slice priority (1-10000)
        SI = minimum time slice in milliseconds (1-10000)
        Return: CF clear if successful
        0003h "SHELL_Crt_VM" create a virtual machine
        ES:EDI -> SEB structure (see #1973)
        Return: CF clear if successful
               EAX = VM handle
            CF set on error
               EDX,EAX = result from GetSetDetailedVMError()
        0004h "SHELL_Destroy_VM" destroy a virtual machine
        EBX = VM handle (not system VM)
        Return: nothing
        0005h "SHELL_Set_Focus"
        EBX = VM handle
        ECX = ???
        Return: nothing
        0006h "SHELL_Get_VM_State"
        EBX = VM handle (not system VM)
        ES:EDI -> ??? structure
        Return: CF clear if successful
        0007h "SHELL_Set_VM_State"
        EBX = VM handle (not system VM)
        ES:EDI -> ??? structure
        0008h "SHELL_Debug_Out"
        ???
        Return: ???
        Note:    dummy function in retail version of MS Windows
        0009h "SHELL_VMDA_Init"
        ???
        Return: ???
        000Ah "SHELL_VMDA_Exit"
        ???
        Return: ???
        000Bh "SHELL_Get_Message_Txt"
        ???
        Return: ???
        000Ch "SHELL_Event_Complete"
        ???
        Return: ???
        000Dh "SHELL_Get_Contention_Info"
        ???
        Return: ???
        000Eh "SHELL_Get_Clip_Info"
        ???
        Return: ???
        000Fh "SHELL_Set_Paste"
        ???
        Return: ???
        0010h "SHELL_Switcher_Assist"
        ???
        Return: ???
        0011h "SHELL_Get_FileSysChng"
        ???
        Return: ???
        0012h "SHELL_Query_Destroy"
        ???
        Return: ???
        0013h "SHELL_SetFocus_Cur_VM" set input focus to current VM
        ???
        Return: ???
        0014h "SHELL_User_Busy_API"
        ???
        Return: ???
        0015h "SHELL_Chng_Hot_Key"
        ???
        Return: ???
        0016h "SHELL_Get_TermInfo"
        ???
        Return: ???
        ---Windows95---
        0017h ???
        0018h ???
        0019h ???
        001Ah ???
        001Bh ???
        001Ch ???
        001Dh ???
        001Eh ???
        001Fh ???
        0020h ???
        0021h ???
        0022h ???
        0023h ???
        0024h ???
        0025h ???
        0026h ???
        Note:    makes VxDCALL 00178002h (see INT 20"Windows")
        0027h ???
        0100h get ??? version
        Return: AX = version??? (0400h for Windows95)
        0101h not implemented
        Return: CF set
            EAX = FFFFFFFFh
        0102h not implemented
        Return: CF set
            EAX = FFFFFFFFh
        0103h not implemented
        Return: CF set
            EAX = FFFFFFFFh
        0104h ???
        0105h ???
        0106h ???
        ???
        Return: CF clear if successful
            CF set on error
        0107h get SDK version for VxD
        AX = VxD identifier
        Return: EAX = VxD ID (high word) and SDK version (low)
                00000000h if no such VxD loaded
        Note:    makes a VMMCALL 0001013Fh (see INT 20"Windows")
              followed by ???
        0108h ???
Return: CF set if called from VM other than system VM
        EAX = FFFFFFFFh
Note:    except for functions 0013h,0026h,and 010xh, this API may only be
      called from the system VM
SeeAlso: #0687 at INT 20"Windows"

Format of Shell Execution Block (SEB):
Offset    Size    Description    (Table 1973)
 00h    DWORD    PIF flags (see #1974)
 04h    DWORD    display flags (see #1975)
 08h    PWORD    -> pathname of .EXE to run
 0Eh    PWORD    -> argument list
 14h    PWORD    -> working drive/directory
 1Ah    WORD    desired number of V86 pages for virtual machine
 1Ch    WORD    minimum number of V86 pages for VM
 1Eh    WORD    foreground priority
 20h    WORD    background priority
 22h    WORD    maximum KB of EMS
 24h    WORD    minimum KB of EMS
 26h    WORD    maximum KB of XMS
 28h    WORD    minimum KB of XMS
 2Ah    WORD    maximum KB of DPMI???
 2Ch    WORD    minimum KB of DPMI???
 2Eh 128 BYTEs    title
Note:    the PWORDs at offsets 08h,0Eh, and 14h consist of a DWORD offset
      followed by a WORD selector

Bitfields for 386 Enhanced Mode PIF flags:
Bit(s)    Description    (Table 1974)
 0    exclusive use of processor when VM is fullscreen
 1    VM runs in background
 2    VM runs in window
 3-4    ???
 5    Alt-Tab reserved
 6    Alt-Esc reserved
 7    Alt-Space reserved
 8    Alt-Enter reserved
 9    Alt-PrtSc reserved
 10    PrtSc reserved
 11    Ctrl-Esc reserved
 12    VM will release idle time slice
 13    VM not allowed to use high memory
 14    ???
 15    VM expanded memory not pageable
 16    VM extended memory not pageable
 17    Fast paste from clipboard enabled
 18    VM application memory not pageable
 30    Close VM when application exits
SeeAlso: #1973,#1975

Bitfields for SHELL display options:
Bit(s)    Description    (Table 1975)
 0    emulate text mode
 1    monitor text port
 2    monitor low graphics port
 3    monitor high graphics port
 7    Retain video memory
SeeAlso: #1973,#1974
--------W-2F1684BX001A-----------------------
INT 2F - MS Windows - VNETWARE - GET API ENTRY POINT
    AX = 1684h
    BX = 001Ah (virtual device ID for VNETWARE device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX001D-----------------------
INT 2F P - MS Windows - WINDEBUG - GET API ENTRY POINT
    AX = 1684h
    BX = 001Dh (virtual device ID for WINDEBUG device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX0021-----------------------
INT 2F PU - MS Windows - PAGEFILE - GET API ENTRY POINT
    AX = 1684h
    BX = 0021h (virtual device ID for PAGEFILE device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #1976)
          0000h:0000h if the VxD does not support an API
SeeAlso: AX=1684h/BX=0017h,#0691 at INT 20"Windows"

(Table 1976)
Call PAGEFILE entry point with:
    AX = function
        0000h get version
        Return: CF clear
            AX = version (AH = major, AL = minor)
        0001h get swap file info
        DS:SI -> 128-byte buffer for swap file full pathname
        DS:DI -> 128-byte buffer for SPART.PAR full pathname
        Return: CF clear
            AL = pager type (see #1977)
            AH = flags
                bit 7: swap file corrupted
            ECX = maximum size of swap file
            DS:SI buffer filled if paging enabled
            DS:DI buffer filled if permanent swap file
        0002h delete permanent swap file on exit
        Return: CF clear
        0003h get current temporary swap file size
        Return: CF clear
            DX:AX = current swap file size in bytes
                0000h:0000h if permanent swap file
Note:    this API is only available in protected mode, and may only be called
      from the system VM
SeeAlso: #0691 at INT 20"Windows",#3476

(Table 1977)
Values for MS Windows PAGEFILE pager type:
 00h    paging disabled
 01h    MSDOS
 02h    BIOS
 03h    32-bit disk access
SeeAlso: #1976
--------W-2F1684BX0022-----------------------
INT 2F P - MS Windows - APIX - GET API ENTRY POINT
    AX = 1684h
    BX = 0022h (virtual device ID for APIX device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3476)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3476)
Call APIX protected-mode entry point with:
    AH = function number
        00h get APIX version
        Return: CF clear
            AH = major version
            AL = minor version
        01h ???
        Return: CF clear
            AX = number of ???
        02h NOP
        Return: CF clear
        03h ???
        Return: CF clear
            AX = 0000h/FFFFh
        else
        Return: CF clear (bug?)
SeeAlso: #1976,#3477
--------W-2F1684BX0026-----------------------
INT 2F P - MS Windows - VPOWERD - GET API ENTRY POINT
    AX = 1684h
    BX = 0026h (virtual device ID for VPOWERD device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3504)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3504)
Call VPOWERD.VXD entry point with:
    AX = function number
        0000h get VPOWERD version
        Return: DX = 0000h
            AX = version (AH = major, AL = minor)
        0001h get APM BIOS version
        Return: DX:AX = APM BIOS version
        0002h get current power management level
        Return: DX:AX = power management level
        0003h enable/disable power management (see INT 15/AX=5308h)
        ??? = new state of power management
        Return: DX:AX = 0000h:0000h if successful
               else error code (see #3506)
        0004h set power state (see INT 15/AX=5307h)
        Return: DX:AX = 0000h:0000h if successful
               else error code (see #3506)
        0005h set system power status
        Return: DX:AX = 0000h:0000h if successful
               else error code (see #3506)
        0006h restore APM power-on defaults (see INT 15/AX=5309h)
        Return: DX:AX = 0000h:0000h if successful
               else error code (see #3506)
        0007h get power status (see INT 15/AX=530Ah)
        Return: ???
        0008h get APM 1.1 power state (see INT 15/AX=530Ch)
        Return: ???
        0009h invoke OEM APM function
        ??? -> buffer containing parameters for INT 15/AX=5380h
        Return: DX:AX = 0000h:0000h or error code (see #3506)
            buffer updated if successful
        000Ah register power handler
        ???
        Return: DX:AX = 0000h:0000h or error code
        000Bh deregister power handler
        ???
        Return: DX:AX = 0000h:0000h or error code (see #3506)
        000Ch Win32 get system power status
        000Dh Win32 set system power status
        else
        Return: DX = 0000h
            AX = 00FFh
SeeAlso: #3476,#3477

(Table 3506)
Values for VPOWERD.VXD error code:
 000000xxh    APM error code
 000000FFh    function number out of range
 80000001h    ??? (service 05h)
 80000002h    ??? (service 0Dh)
 80000003h    specified NULL buffer pointer (service 07h,08h,09h)
 80000005h    ??? (service 03h)
 80000006h    ??? (service 04h)
 80000007h    ??? (service 05h)
 80000008h    ??? (service 05h)
 80000009h    out of memory (service 0Ah)
 8000000Ah    ??? (service 0Ah)
 8000000Bh    invalid power handler (service 0Bh)
 8000000Ch    unsupported/disabled??? function
SeeAlso: #3504,#3505
--------W-2F1684BX0027-----------------------
INT 2F - MS Windows95 - VXDLDR - GET API ENTRY POINT
    AX = 1684h
    BX = 0027h (virtual device ID for VXDLDR device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3477)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3477)
Call VXDLDR entry point with:
    EAX = function number
        0000h get VXDLDR version
        Return: CF clear
            AX = 0000h (successful)
            DH = major version
            DL = minor version
        0001h load device
        ???
        Return: CF clear if successful
                AX = 0000h
            CF set on error
                AX = error code (see #3478)
        0002h unload device
        BX = ???
        Return: CF clear if successful
                AX = 0000h
            CF set on error
                AX = error code (see #3478)
        else
        Return: CF set
            AX = 000Bh
SeeAlso: #3504,#3479

(Table 3478)
Values for VXDLDR error code:
 0000h    successful
 000Bh    invalid function number
SeeAlso: #3477
--------W-2F1684BX0028-----------------------
INT 2F - MS Windows - NDIS - GET API ENTRY POINT
    AX = 1684h
    BX = 0028h (virtual device ID for NDIS device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3479)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3479)
Call NDIS.VXD entry point with:
    ??? = function number
        0000h set ??? to ???
        ??? = new ???
        Return: DX:AX = 0000h:0001h
        0002h ???
        ???
        Return: DX:AX -> ???
        0003h reset ??? to default
        Return: DX:AX = 0000h:0001h
        else
        Return: DX:AX = 0000h:0000h
SeeAlso: #3477,#3480
--------W-2F1684BX002A-----------------------
INT 2F P - MS Windows - VWIN32 - GET API ENTRY POINT
    AX = 1684h
    BX = 002Ah (virtual device ID for VWIN32 device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3480)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3480)
Call VWIN32.VXD entry point with:
    AH = function number
        00h get VWIN32 version and ???
        Return: CF clear
            AH = major version
            AL = minor version
            EDX = ???
        01h ???
        EBX = ???
        ECX = ???
        Return: CF clear
            EAX = ???
        02h ???
        Return: CF clear
            AX = ??? or 0000h
        03h address allocation
        DS:??? -> buffer containing/for page data
        ECX = length of buffer
        AL = subfunction
            00h reserve page(s)
            01h commit page(s)
            02h decommit page(s)
            03h free page(s)
        Return: CF clear if successful
            CF set on error
        Note:    this function uses ECX bytes of stack
        04h get ???
        Return: CF clear
            EAX = ???
        05h ???
        EBX = ???
        Return: CF clear
            EAX = ???
        06h ???
        EBX = ???
        Return: CF clear
            EAX = ???
        07h ???
        EBX = ???
        Return: CF clear
            EAX = ???
        08h get ???
        Return: CF clear
            AX = ???
        09h ???
        EBX = ???
        ECX = ???
        Return: CF clear
        0Ah ???
        EBX = ???
        Return: CF clear
        0Bh ???
        EBX = ???
        Return: CF clear
        0Ch ???
        EBX = ???
        ECX = ???
        EDX = ???
        ???
        Return: CF clear if successful
                EAX = ???
            CF set on error
        0Dh clear ???
        Return: CF clear
        0Eh ???
        EBX = ???
        ECX = ???
        Return: CF clear
        0Fh ???
        EBX = ???
        ECX = ???
        Return: CF clear
        10h ???
        Return: CF clear
        Note:    invokes VMMcall 00010184h
        11h ???
        Return: CF clear
        Note:    invokes VMMcall 00010160h
        12h ???
        ???
        13h pop up system error dialogue
        Return: CF clear
            AX = ??? or 0000h
        14h "IFSMgr_GetConversionTablePtrs"
        Return:    CF clear
            DX:AX -> ???
        Note:    invokes VxDcall 00400051h
        15h "Boost_With_Decay"
        EBX = ???
        ECX = ???
        EDX = ???
        Return: CF clear
        else
        Return: CF set
SeeAlso: #3479,#3481
--------W-2F1684BX002B-----------------------
INT 2F - MS Windows - VCOMM - GET API ENTRY POINT
    AX = 1684h
    BX = 002Bh (virtual device ID for VCOMM device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3481)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3481)
Call VCOMM.VXD entry point with:
    AX = function number
        0000h open COM/LPT port
        BX = port number (00h-7Fh = COMx, 80h-FFh = LPTx)
        Return: DX:AX = ???
        0001h set comm state
        ???
        Return: AX = ???
        0002h setup comm port
        ???
        Return: AX = status (0000h failed, FFFFh success)
        0003h transmit character
        EBX = handle???
        ECX = ???
        Return: AX = status???
        0004h close comm port
        EBX = handle???
        Return: ???
        0005h clear comm error
        EBX = handle???
        EAX = ???
        Return: AX = status???
        0006h "EscapeCommFunction"
        EBX = handle???
        ECX = ???
        EAX = ???
        Return: DX:AX = ???
        0007h purge buffers
        EBX = handle???
        CX = ???
        Return: AX = status???
        0008h set comm event mask
        EBX = handle???
        CX = new event mask
        Return: AX = status???
        0009h get comm event mask
        EBX = handle???
        Return: AX = current event mask
        000Ah ???
        EBX = handle???
        Return: ???
        000Bh "WriteComm"
        EBX = handle???
        ECX = number of characters to write
        Return: AX = status
            EAX high word may be destroyed
        000Ch "ReadComm"
        EBX = handle???
        ECX = number of bytes to read
        Return: AX = status ???
            ZF = ???
        000Dh set ??? callback
        EBX = handle???
        ECX = ???
        EDX = ???
        Return: AX = status???
        else
        Return: AX = 0000h
SeeAlso: #3480,#3507
--------W-2F1684BX002D-----------------------
INT 2F P - MS Windows - W32S - GET API ENTRY POINT
    AX = 1684h
    BX = 002Dh (virtual device ID for W32S device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX0027-----------------------
INT 2F P - MS Windows - MACH32 - GET API ENTRY POINT
    AX = 1684h
    BX = 0030h (virtual device ID for MACH32 device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX0032-----------------------
INT 2F - MS Windows - SERVER / VSERVER - GET API ENTRY POINT
    AX = 1684h
    BX = 0032h (virtual device ID for SERVER device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3507)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",#3389 at INT 20"Windows"

(Table 3507)
Call Windows95 VSERVER.VXD protected-mode entry point with:
    AX = function number
        0003h NOP
        Return: AX = 0000h
        0004h NOP
        Return: AX = 0000h
        0007h NOP
        Return: AX = 0000h
        0008h NOP
        Return: nothing
        000Fh ???
        Return: AX = status
                0000h successful
                0842h on error
        0010h ???
        Return: AX = status
                0000h successful
                0842h on error
        else
        Return: AX = 0032h
SeeAlso: #3481,#3482
--------W-2F1684BX0033-----------------------
INT 2F - MS Windows - CONFIGMG - GET API ENTRY POINT
    AX = 1684h
    BX = 0033h (virtual device ID for CONFIGMG device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3482)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3482)
Call CONFIGMG.VXD entry point with:
    AX = function number
        0000h get CONFIGMG version
        Return: CF clear
            AH = major version
            AL = minor version
        ...
        005Ah
        else
        Return: CF set
            AX = 0020h
SeeAlso: #3357 at INT 20"Windows",#3507,#1978
--------x-2F1684BX0034-----------------------
INT 2F - Intel Plug-and-Play - CONFIGURATION MANAGER - GET ENTRY POINT
    AX = 1684h
    BX = 0034h (ID for Configuration Manager) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> API entry point (see #1978)
          0000h:0000h if Configuration Manager not loaded
Note:    this API is often provided by a DOS device driver, in which case it
      is available whether or not MSWindows is running
Index:    installation check;Plug-and-Play Configuration Manager
SeeAlso: AX=1684h/BX=304Ch

(Table 1978)
Call Configuration Manager entry point with:
    AX = function
        0000h "CM_GetVersion" get supported DDI version
        Return: AH = BCD major version
            AL = BCD minor version
            BX = number of devices identified by configuration
        Note:    returns AX = 0000h if no config manager installed
        0001h "CM_GetConfig" get device configuration
        BX = device index
        ES:DI -> buffer for configuration information (see #1980)
        Return: AX = status
                0000h successful
                ES:DI buffer filled
                other error code (0001h = index out of range)
        0002h "CM_LockConfig" lock device configuration
        ES:DI -> configuration information (see #1980)
        Return: AX = status
                0000h successful
                ES:DI buffer filled with assigned config
                0001h resources conflict
                0002h invalid request or configuration info
        0003h "CM_UnlockConfig" unlock device configuration
        ES:DI -> configuration information (see #1980)
        Return: AX = status
                0000h successful
                ES:DI buffer filled with assigned config
                0001h invalid request or configuration info
        0004h "CME_QueryResources" get hot-swappable resources
        ES:DI -> configuration information (see #1980)
        Return: AX = status (see #1979)
        0005h "CME_AllocResources" remove resources from available pool
        ES:DI -> configuration information (see #1980)
        Return: AX = status (see #1979)
        0006h "CME_DeallocResources" return resources to available pool
        ES:DI -> configuration information (see #1980)
        Return: AX = status (see #1979)
SeeAlso: #3461 at INT 20"Windows",#3482,#3483

(Table 1979)
Values for Configuration Manager status:
 00h    successful
 01h    device not found, configuration error
 02h    I/O port unavailable
 04h    IRQ unavailable
 08h    DMA channel unavailable
 10h    memory range unavailable
SeeAlso: #1978

Format of Configuration Information Structure:
Offset    Size    Description    (Table 1980)
 00h    DWORD    bus ID
 04h    DWORD    device ID
 08h    DWORD    serial number
 0Ch    DWORD    logical ID
 10h    DWORD    flags
---ISA bus---
 14h    BYTE    Card Select Number
 15h    BYTE    logical device number
 16h    WORD    Read Data port
------
 18h    WORD    number of memory windows
 1Ah  9 DWORDs    physical base addresses of memory windows
 3Eh  9 DWORDs    length of memory windows
 62h  9 WORDs    memory window attributes
 74h    WORD    number of I/O ports
 76h 20 WORDs    I/O port base addresses
 B6h 20 WORDs    lengths of I/O port ranges
 F6h    WORD    number of IRQs
 F8h  7 BYTEs    IRQ registers
 FFh  7 BYTEs    IRQ attributes
106h    WORD    number of DMA channels
108h  7 BYTEs    DMA channels used
10Fh  7 WORDs    DMA channel attributes
11Dh  3 BYTEs    reserved
SeeAlso: #1978
--------W-2F1684BX0036-----------------------
INT 2F - MS Windows - VFBACKUP - GET API ENTRY POINT
    AX = 1684h
    BX = 0036h (virtual device ID for VFBACKUP device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3483)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3483)
Call VFBACKUP.VXD entry point with:
    nothing -- this API is a NOP for the default Windows95 VFBACKUP
SeeAlso: #1978,#3408
--------W-2F1684BX0037-----------------------
INT 2F - MS Windows - ENABLE.VXD - GET API ENTRY POINT
    AX = 1684h
    BX = 0037h (virtual device ID for ENABLE device) (see #3508)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3483)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3508)
Call Windows95 ENABLE.VXD entry point with:
    AX = function number
        0000h get ENABLE version
        Return:    CF clear
            AX = version (AH = major, AL = minor)
        0001h
        EBX = ???
        Return: ???
        0002h get ???
        Return: CF clear
            DX:AX = ???
        0003h get ???
        Return: CF clear
            DX:AX = ???
        0004h ???
        EBX = ???
        ECX = ???
        EDX = ???
        Return: CF clear if successful
            CF set on error
        else
        Return: CF set
SeeAlso: #3483,#3484
--------W-2F1684BX0038-----------------------
INT 2F - MS Windows - VCOND - GET API ENTRY POINT
    AX = 1684h
    BX = 0038h (virtual device ID for VCOND device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3484)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3484)
Call VCOND.VXD virtual-86 entry point with:
    AX = function number
        0202h
        0203h
        0204h
        0205h
        0206h
        0207h
        0208h
        0209h
        020Ah
        020Bh
        020Dh
        020Eh
        020Fh
        0210h
        0401h
        0402h
        0403h
        0404h
        0405h
        else
        NOP
SeeAlso: #3485,#3508

(Table 3485)
Call VCOND.VXD protected-mode entry point with:
    AX = function number
        0301h
        0302h
        0303h
        0304h
        0305h
        0306h
        0307h
        0308h
        else
        NOP
SeeAlso: #3484,#3483
--------W-2F1684BX003B-----------------------
INT 2F - MS Windows - DSVXD - GET API ENTRY POINT
    AX = 1684h
    BX = 003Bh (virtual device ID for DSVXD device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX0027-----------------------
INT 2F - MS Windows - BIOS VxD - GET API ENTRY POINT
    AX = 1684h
    BX = 003Dh (virtual device ID for BIOS device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3486)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3486)
Call BIOS.VXD entry point with:
    AX = function number
        0000h get BIOS.VXD version
        Return: CF clear
            AH = major version
            AL = minor version
        0100h ???
        Return: AX = 0000h
        Note:    calls CONFIGMG services 804Eh/804Fh
        0200h ???
        Return: CF clear if successful
                AX = ???
            CF set on error
                AX = error code???
        Note:    invokes VxDcall 00290002h
        0300h ???
        Return: CF clear if successful
                AX = ???
            CF set on error
                AX = error code???
        else
        Return: CF set
SeeAlso: #3485,#3487
--------W-2F1684BX003E-----------------------
INT 2F - MS Windows - WSOCK - GET API ENTRY POINT
    AX = 1684h
    BX = 003Eh (virtual device ID for WSOCK device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX011F-----------------------
INT 2F P - MS Windows - VFLATD - GET API ENTRY POINT
    AX = 1684h
    BX = 011Fh (virtual device ID for VFLATD device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3487)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3487)
Call VFLATD.VXD entry point with:
    DL = function number
        00h get VFLATD version and ???
        Return: CF clear
            EAX = version (AH = major, AL = minor)
            EBX = ???
            ECX = ???
            EDX = ??? or 00000000h
        01h ???
        AX = ???
        CX = ???
        Return: EAX = ???
            EDX = ???
        02h ???
        ???
        03h ???
        EAX = ???
        EBX = ???
        ESI = ???
        CX = ???
        DH = ???
        Return: EAX = ???
            EDX = ???
            CF clear
        04h ???
        DH = ???
        EAX = ???
        ECX = ???
        Return: CF clear
            EAX = ???
            EDX = ???
        05h ???
        ???
        Note:    locks some linear memory and calls fn 02h
        06h ???
        ???
        Return: CF clear if successful
            CF set on error
        Note:    calls fn 02h and unlocks some linear memory
        else
        Return: CF set
SeeAlso: #3486
--------W-2F1684BX0200-----------------------
INT 2F - MS Windows - VIPX - GET API ENTRY POINT
    AX = 1684h
    BX = 0200h (virtual device ID for VIPX device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX0202-----------------------
INT 2F - MS Windows - WINICE - GET API ENTRY POINT
    AX = 1684h
    BX = 0202h (virtual device ID for WINICE device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX0203-----------------------
INT 2F P - MS Windows - VCLIENT - GET API ENTRY POINT
    AX = 1684h
    BX = 0203h (virtual device ID for VCLIENT device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX0205-----------------------
INT 2F - MS Windows - BCW - GET API ENTRY POINT
    AX = 1684h
    BX = 0205h (virtual device ID for BCW device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX0207-----------------------
INT 2F R - MS Windows - DPMS VxD - GET API ENTRY POINT
    AX = 1684h
    BX = 0207h (virtual device ID for DPMS device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX0234-----------------------
INT 2F - MS Windows - VCOMMUTE - GET API ENTRY POINT
    AX = 1684h
    BX = 0234h (virtual device ID for VCOMMUTE device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX0027-----------------------
INT 2F P - MS Windows - VTDAPI - GET API ENTRY POINT
    AX = 1684h
    BX = 0442h (virtual device ID for VTDAPI device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3488)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3488)
Call VTDAPI.VXD entry point with:
    EAX = function number
        0000h
        0001h
        0002h
        0003h
        0004h
        0005h
        0006h
        0007h
        0008h
        0009h
        000Ah
        000Bh
        else
        Return: nothing???
SeeAlso: #3488
--------W-2F1684BX0444-----------------------
INT 2F - MS Windows - VADMAD - GET API ENTRY POINT
    AX = 1684h
    BX = 0444h (virtual device ID for VADMAD device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #1981)
          0000h:0000h if the VxD does not support an API

(Table 1981)
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)
SeeAlso: #0674 at INT 20"Windows"
--------W-2F1684BX0445-----------------------
INT 2F - MS Windows - VSBD - GET API ENTRY POINT
    AX = 1684h
    BX = 0445h (virtual device ID for VSBD device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX0446-----------------------
INT 2F - MS Windows - VADLIBD - GET API ENTRY POINT
    AX = 1684h
    BX = 0446h (virtual device ID for VADLIBD device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX0449-----------------------
INT 2F P - MS Windows - vjoyd - GET API ENTRY POINT
    AX = 1684h
    BX = 0449h (virtual device ID for "vjoyd" device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3489)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3489)
Call VJOYD.VXD entry point with:
    AX = function number
        0000h get VJOYD version
        Return: AH = major version
            AL = minor version
        0001h ???
        DX = ???
        Return: DX:AX = ???
        0002h ???
        DX = ???
        Return: DX:AX = ???
        0003h ???
        Retrun: AX = 0001h
        0004h ???
        DX = ???
        Return: DX:AX = ???
        0005h ???
        Return: ???
        else
        Return: EAX = 00000000h
SeeAlso: #3488,#3490
--------W-2F1684BX044A-----------------------
INT 2F - MS Windows - mmdevldr - GET API ENTRY POINT
    AX = 1684h
    BX = 044Ah (virtual device ID for "mmdevldr" device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3490)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3490)
Call MMDEVLDR.VXD entry point with:
    DX = function number
        0000h ???
        Return: CF clear if successful
                AX = 0000h
            CF set on error
                AX = error code (000Bh)
        Note:    invokes VxDCall 17000Eh ("CallAtAppyTime")
        0001h ???
        Return: CF clear if successful
                AX = 0000h
            CF set on error
                AX = error code (000Bh)
        Note:    invokes VxDCall 17000Eh ("CallAtAppyTime")
        0002h ???
        EDX = ???
        Return: CF clear if successful
                AX = 0000h
                EDX = ???
            CF set on error
                AX = error code
        0003h ???
        Return: CF clear if successful
                AX = 0000h
            CF set on error
                AX = error code
        Note:    invokes VxDcall 2A0002h ("VWIN32_QueueUserApc")
        0004h set Win32 event
        Return: CF clear if successful
                AX = 0000h
            CF set on error
                AX = error code
        Note:    invokes VxDcall 2A000Eh ("VWIN32_SetWin32Event")
        0005h ??? (allocates some memory)
        Return: CF clear
            AX = 0000h
        0006h ??? (frees memory)
        Return: CF clear if successful
                AX = 0000h
            CF set on error
                AX = error code
        else
        Return: CF set
            AX = 000Bh (invalid function)
SeeAlso: #3489,#3491
--------W-2F1684BX045D-----------------------
INT 2F P - MS Windows - VflatD - GET API ENTRY POINT
    AX = 1684h
    BX = 045Dh (virtual device ID for VflatD device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX045F-----------------------
INT 2F - MS Windows - azt16 - GET API ENTRY POINT
    AX = 1684h
    BX = 045Fh (virtual device ID for "azt16" device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3491)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3491)
Call azt16.VXD entry point with:
    DX = function number
        0000h get azt16 version
        Return: CF clear
            AX = version (AH=major, AL=minor)
        0001h ???
        AX = subfunction
            0000h ???
            Return:
            0001h ???
            ECX = ???
            else error
        Return: CF clear if successful
                ???
            CF set on error
                AX = error code
        0002h ???
        AX = ???
        BX = ???
        Return: ???
        0003h ???
        AX = ???
        BX = ???
        Return: ???
        0004h ???
        BX = ???
        CX = ???
        Return: CF clear if successful
                 AX = 0001h
            CF set on error
                 AX = 0000h
        0005h ???
        BX = ???
        CX = ???
        Return: CF clear if successful
                 AX = 0001h
            CF set on error
                 AX = 0000h
        0006h ???
        BX = ???
        ECX = ???
        Return: CF clear if succesful
                AX = ???
            CF set on error
                AX = FFFFh
        0100h get azt16 version
        Return: CF clear
            AX = version (AH=major, AL=minor)
        0101h
        AX = ???
        ECX = ???
        Return: CF clear if successful
                AX = 0001h
            CF set on error
                AX = 0000h
        0102h ???
        AX = ???
        Return: CF clear if successful
            CF set on error
                AX = reason??? (0/1/2)
        0103h ???
        AX = ???
        Return: CF clear if successful
                AX = 0000h
            CF set on error
                AX = reason??? (1/3)
        0200h ???
        EDX = ???
        ???
        Return: CF clear if successful
                DX:AX = ???
            CF set on error
                DX:AX = 0000h:0000h
        0201h ???
        ???
        Return: CF clear
            AX= 0000h
        else
        Return: CF set
SeeAlso: #3490
--------W-2F1684BX0460-----------------------
INT 2F P - MS Windows - UNIMODEM - GET API ENTRY POINT
    AX = 1684h
    BX = 0460h (virtual device ID for UNIMODEM device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3492)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3492)
Call UNIMODEM.VXD protected-mode entry point with:
    AX = function number
        0000h
        Return: AX = ???
        0001h
        Return: AX = ???
        0002h
        Return: AX = ???
        0003h
        Return: AX = ???
        0004h
        Return: AX = ???
        0005h
        Return: AX = ???
        0006h
        Return: AX = ???
        0007h
        Return: AX = ???
        else
        Return: AX = 0002h
SeeAlso: #3491,#3493
--------W-2F1684BX0480-----------------------
INT 2F - MS Windows - VNetSup - GET API ENTRY POINT
    AX = 1684h
    BX = 0480h (virtual device ID for VNetSup device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3493)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3493)
Call VNetSup.VXD entry point with:
    AX = function number
        0000h
        Return: AX = ???
        0001h
        Return: AX = ???
        0002h
        Return: AX = ???
        else
        Return: CF set
            AX = 0001h
SeeAlso: #3492,#3494
--------W-2F1684BX0482-----------------------
INT 2F - MS Windows - VBrowse - GET API ENTRY POINT
    AX = 1684h
    BX = 0482h (virtual device ID for VBrowse device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX0027-----------------------
INT 2F - MS Windows - VSHARE - GET API ENTRY POINT
    AX = 1684h
    BX = 0483h (virtual device ID for VSHARE device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3494)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3494)
Call Windows95 VSHARE.VXD entry point with:
    AX = function number
        0000h get VSHARE version
        Return: AH = major version
            AL = (BCD?) minor version
        else
        NOP
SeeAlso: #3493
--------W-2F1684BX0027-----------------------
INT 2F P - MS Windows - IFSMgr - GET API ENTRY POINT
    AX = 1684h
    BX = 0484h (virtual device ID for IFSMgr device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX0486-----------------------
INT 2F - MS Windows - VFAT - GET API ENTRY POINT
    AX = 1684h
    BX = 0486h (virtual device ID for VFAT device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX0487-----------------------
INT 2F - MS Windows - NWLINK - GET API ENTRY POINT
    AX = 1684h
    BX = 0487h (virtual device ID for NWLINK device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX0489-----------------------
INT 2F R - MS Windows - VIP - GET API ENTRY POINT
    AX = 1684h
    BX = 0489h (virtual device ID for VIP device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX048A-----------------------
INT 2F - MS Windows 3.11 - VXDLDR - GET API ENTRY POINT
    AX = 1684h
    BX = 048Ah (virtual device ID for VTCP device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX0027-----------------------
INT 2F - MS Windows - VCACHE - GET API ENTRY POINT
    AX = 1684h
    BX = 048Ah (virtual device ID for VCACHE device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3496)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3495)
Call Windows95 VCACHE.VXD entry point with:
    Return:    CF set
SeeAlso: #3494,#3496
--------W-2F1684BX048D-----------------------
INT 2F - MS Windows - RASMAC - GET API ENTRY POINT
    AX = 1684h
    BX = 048Dh (virtual device ID for RASMAC device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX048E-----------------------
INT 2F - MS Windows - NWREDIR - GET API ENTRY POINT
    AX = 1684h
    BX = 048Eh (virtual device ID for NWREDIR device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3496)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3496)
Call Windows95 NWREDIR.VXD entry point with:
    Return:    CF set
        EAX = FFFFFFFFh
SeeAlso: #3495
--------W-2F1684BX0494-----------------------
INT 2F - MS Windows - NSCL - GET API ENTRY POINT
    AX = 1684h
    BX = 0494h (virtual device ID for NSCL device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3497,#3498)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3497)
Call Windows95 NSCL.VXD virtual-86 entry point with:
    AL = function number
        00h
        01h
        02h
        03h
        04h
        05h
        06h
        07h
        08h
        09h
        0Ah
        else
        Return: AX = FFFFh
SeeAlso: #3496,#3497

(Table 3498)
Call Windows95 NSCL.VXD protected-mode entry point with:
    AL = function number
        00h
        01h
        02h
        03h
        else
        Return: AX = FFFFh
SeeAlso: #3497
--------W-2F1684BX0499-----------------------
INT 2F - MS Windows - PPPMAC - GET API ENTRY POINT
    AX = 1684h
    BX = 0499h (virtual device ID for PPPMAC device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX049A-----------------------
INT 2F - MS Windows - VDHCP - GET API ENTRY POINT
    AX = 1684h
    BX = 049Ah (virtual device ID for VDHCP device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX049B-----------------------
INT 2F - MS Windows - VNBT - GET API ENTRY POINT
    AX = 1684h
    BX = 049Bh (virtual device ID for VNBT device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX1021-----------------------
INT 2F - MS Windows - VMB - GET API ENTRY POINT
    AX = 1684h
    BX = 1021h (virtual device ID for VMB device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX28A0-----------------------
INT 2F - MS Windows - PHARLAPX - GET API ENTRY POINT
    AX = 1684h
    BX = 28A0h (virtual device ID for PHARLAPX device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #1983)
          0000h:0000h if the VxD does not support an API

(Table 1983)
Call PHARLAPX VxD entry point with:
    AX = function
        0001h get PHARLAP.386 version
        Return: AX = version number (AH = major, AL = minor)
    ---queue functions---
        0101h allocate a new message queue
        CX = size of queue data buffer in bytes
        Return: DX:AX = handle for new queue, or 0000h:0000h on error
        0102h allocate a new key queue
        CX = size of queue data buffer in bytes
        EDX = VM handle into which keys will be pasted
        Return: DX:AX = handle for new queue, or 0000h:0000h on error
        0103h free message queue
        EDX = queue handle
        Return: AX = status (0000h,0003h,0007h) (see #1984)
        0104h free key queue
        EDX = queue handle
        Return: AX = status (0000h,0003h,0005h) (see #1984)
        0105h add message to communications queue
        EDX = queue handle
        BX = length of message data in bytes
        CX = length of message header in bytes
        ES:(E)SI -> message header
        GS:(E)DI -> message data
        Return: AX = status (0000h-0003h,0007h) (see #1984)
        0106h remove message from queue
        EDX = queue handle
        CX = length of buffer in bytes
        ES:(E)SI -> buffer for message
        Return: AX = status (0000h,0003h,0006h,0007h,0008h) (see #1984)
            CX = length of returned message (if AX=0000h or 0008h)
        0107h flush queue (remove all data)
        EDX = queue handle
        Return: AX = status (0000h,0003h) (see #1984)
        0108h add PasteKey structure(s) to key queue
        EDX = queue handle
        CX = number of PasteKey structures in buffer
        ES:(E)SI -> PasteKey array (see #1985)
        Return: AX = status (0000h-0003h) (see #1984)
        0109h register enqueueing callback function
        EDX = queue handle
        ECX = function argument
        ES:(E)SI -> callback function
        Return: AX = status (0000h,0003h,0009h) (see #1984)
        010Ah register dequeueing callback function
        EDX = queue handle
        ECX = function argument
        ES:(E)SI -> callback function
        Return: AX = status (0000h,0003h,0009h) (see #1984)
        010Bh unregister enqueueing callback function
        EDX = queue handle
        Return: AX = status (0000h,0003h,0009h) (see #1984)
        010Ch unregister dequeueing callback function
        EDX = queue handle
        Return: AX = status (0000h,0003h,0009h) (see #1984)
        010Dh get message queue status
        EDX = queue handle
        Return: AX = status (0000h,0003h) (see #1984)
            CX = number of pending messages
        010Eh peek at message in queue
        EDX = queue handle
        BX = number of message in queue (0000h = first)
        CX = size of buffer in bytes
        ES:(E)SI -> buffer for message
        Return: AX = status (0000h,0003h,0006h,0008h) (see #1984)
            CX = length of returned message (if AX=0000h or 0008h)
        010Fh peek at last message in queue
        EDX = queue handle
        CX = size of buffer in bytes
        ES:(E)SI -> buffer for message
        Return: AX = status (0000h,0003h,0006h,0008h) (see #1984)
            CX = length of returned message (if AX=0000h or 0008h)
        0110h replace last message in queue
        EDX = queue handle
        CX = length of message header in bytes
        BX = length of message data in bytes
        ES:(E)SI -> message header
        GS:(E)DI -> message data
        Return: AX = status (0000h,0002h,0003h) (see #1984)
        0111h set permitted message count for queue
        EDX = queue handle
        CX = maximum number of messages to enqueue (FFFFh = unlimited)
        Return: AX = status (0000h,0003h) (see #1984)
    ---generalized VxD services---
        0202h call VxD function
        ES:(E)BX -> in/out register-set buffer
        Return: buffer updated
        0203h map flat
        ???
    --system register functions---
        0301h read system registers into buffer
        ES:(E)SI -> 512-byte buffer
        Return: AX = 0000h
            buffer filled (mostly zeros)
        0302h copy linear memory into buffer
        EDX = linear address
        CX = number of bytes to copy
        ES:(E)SI -> buffer
        Return: AX = 0000h
        0303h copy data into linear memory
        EDX = linear address
        CX = number of bytes to copy
        ES:(E)SI -> buffer
        Return: AX = 0000h
        0304h freeze VM
        ???
        0305h unfreeze VM
        ???
    ---name registration functions---
        0401h register name
        EDX = magic number to associate with name
        ES:(E)SI -> name to register
        Return: AX = status (0000h,0009h) (see #1984)
        0402h unregister name
        ES:(E)SI -> name to be unregistered
        Return: AX = status (0000h,0009h) (see #1984)
        0403h look up name
        ES:(E)SI -> name to look up
        Return: DX:AX = magic number or 0000h:0000h if not registered
        0404h get name list handle
        Return: DX:AX = name list handle
                0000h:0000h if not initialized
    ---special DOS server routines (undocumented)---
        0501h register
        0502h unregister
        0503h validate VM
        0504h get INT9 count
        0505h get screen line
        0506h get shift status
        0507h get server PB pointer
        0508h initialize DOS shell
        0509h get last VM handle

(Table 1984)
Values for PHARLAPX function status:
 00h    successful
 01h    data is too large to fit in queue
 02h    queue is full
 03h    invalid queue handle
 04h    invalid VM handle for queue
 05h    error starting a paste operation
 06h    queue is empty
 07h    a VM is blocked waiting on the queue
 08h    message was too long (truncated)
 09h    unable to register or unregister specified callback
SeeAlso: #1983

Format of PHARLAPX PasteKey structure:
Offset    Size    Description    (Table 1985)
 00h    BYTE    ASCII code
 01h    BYTE    scan code (see #0005)
 02h    WORD    shift states
SeeAlso: #1983

Format of PHARLAPX VxD-call register structure:
Offset    Size    Description    (Table 1986)
 00h    DWORD    call number
 04h    WORD    input register map (see #1987)
 06h    WORD    output register map (see #1987)
 08h  7 DWORDs    values for EAX, EBX, ECX, EDX, EBP, ESI, EDI on call
 24h  4    WORDs    values for DS, ES, FG, GS on call
 2Ch    DWORD    EFLAGS on call
 30h  7 DWORDs    returned values of EAX, EBX, ECX, EDX, EBP, ESI, EDI
 4Ch  4 WORDs    returned values of DS, ES, FS, GS
 54h    DWORD    returned EFLAGS
SeeAlso: #1983

Bitfields for PHARLAPX VxD-call register map:
Bit(s)    Description    (Table 1987)
 0    value in EAX field is valid
 1    value in EBX field is valid
 2    value in ECX field is valid
 3    value in EDX field is valid
 4    value in EBP field is valid
 5    value in ESI field is valid
 6    value in EDI field is valid
 7    value in DS field is valid
 8    value in ES field is valid
 9    value in FS field is valid
 10    value in GS field is valid
 11    value in EFLAGS field is valid
SeeAlso: #1986
--------W-2F1684BX28A1-----------------------
INT 2F - MS Windows - PharLap VxD - GET API ENTRY POINT
    AX = 1684h
    BX = 28A1h (virtual device ID for PharLap device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",AX=1684h/BX=28A0h,INT 20"Windows"
--------W-2F1684BX2925-----------------------
INT 2F - MS Windows - EDOS - GET API ENTRY POINT
    AX = 1684h
    BX = 2925h (virtual device ID for EDOS device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #1988)
          0000h:0000h if the VxD does not support an API

(Table 1988)
Call EDOS entry point with:
    AX = 0000h get EDOS version number
        Return: AH = major version
            AL = minor version
    AX = 0001h display message
        CX = 0
        DX:BX -> ASCIZ Message
    AX = 0002h get EDOS error coded
        Return: EAX = time in milliseconds that Windows has been running
    AX = 0003h execute windows program
        Return: EAX = cumulative amount of time the virtual machine has
            been active, in milliseconds
    AX = 0008h get/set priority
        BX = 0000h??? foreground
         0001h background
        DI = 0000h get
         0001h set
        DX = priority setting
        Return: CX = foreground priority
            DX = background priority
            BX:AX = flags
            00000001h exclusive ON
            00000010h background ON
            SI = CPU percentage
--------W-2F1684BX292D-----------------------
INT 2F - MS Windows - VSBPD - GET API ENTRY POINT
    AX = 1684h
    BX = 292Dh (virtual device ID for VSBPD device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------W-2F1684BX295A-----------------------
INT 2F - MS Windows - GRVSULTR - GET API ENTRY POINT
    AX = 1684h
    BX = 295Ah (virtual device ID for GRVSULTR device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
--------x-2F1684BX304C-----------------------
INT 2F - Intel Plug-and-Play - CONFIGURATION ACCESS - GET ENTRY POINT
    AX = 1684h
    BX = 304Ch (ID for Configuration Access) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> API entry point (see #1989)
          0000h:0000h if Configuration Access not loaded
Note:    this API is often provided by a DOS device driver, in which case it
      is available whether or not MSWindows is running
Index:    installation check;Plug-and-Play Configuration Access
SeeAlso: AX=1684h/BX=0034h

(Table 1989)
Call Plug-and-Play Configuration Access entry point with:
    AX = function
        0000h "CA_GetVersion"
        Return: AX = BCD version (AH = major, AL = minor)
        0001h "CA_PCI_Read_Config_Byte" (see also INT 1A/AX=B108h)
    !!!
        0002h "CA_PCI_Read_Config_Word" (see also INT 1A/AX=B109h)
        0003h "CA_PCI_Read_Config_DWord" (see also INT 1A/AX=B10Ah)
        0004h "CA_PCI_Write_Config_Byte" (see also INT 1A/AX=B10Bh)
        0005h "CA_PCI_Write_Config_Word" (see also INT 1A/AX=B10Ch)
        0006h "CA_PCI_Write_Config_DWord" (see also INT 1A/AX=B10Dh)
        0007h "CA_PCI_Generate_Special_Cycle" (see also INT 1A/AX=B106h)
        0008h "CA_PCI_Get_Routing_Options" (see also INT 1A/AX=B10Eh)
        0009h invalid function
        000Ah invalid function
        000Bh "CA_PnPISA_Get_Info"
        000Ch "CA_PnPISA_Read_Config_Byte"
        000Dh "CA_PnPISA_Write_Config_Byte"
        000Eh "CA_PnPISA_Get_Resource_Data"
        000Fh invalid function
        0010h "CA_EISA_Get_Board_ID"
        0011h "CA_EISA_Get_Slot_Config"
        0012h "CA_EISA_Get_SlotFunc_Config"
        0013h "CA_EISA_Clear_NVRAM_Config"
        0014h "CA_EISA_Write_Config"
        0015h invalid function
        0016h "CA_ESCD_Get_Info"
        0017h "CA_ESCD_Read_Config"
        0018h "CA_ESCD_Write_Config"
        0019h invalid function
        001Ah "CA_Acfg_PCI_Manage_IRQs"
        DL = IRQ???
        ES:DI -> ???
        Return: AX = status
        001Bh "CA_Acfg_PCI_Get_Routing_Options"
        ES:DI -> IRQ routing table header
              (see #0666 at INT 1A/AX=B406h)
        Return: AX = status
        001Ch-001Fh invalid functions
        0020h "CA_PnPB_Get_Num_Sys_Dev_Nodes"
        0021h "CA_PnPB_Get_Sys_Dev_Node"
        0022h "CA_PnPB_Set_Sys_Dev_Node"
        0023h "CA_PnPB_Get_Stat_Res_Info"
        0024h "CA_PnPB_Set_Stat_Res_Info"
Return: AX = FFFFh if unsupported function
SeeAlso: #3501
--------W-2F1684BX3099-----------------------
INT 2F - MS Windows - VVidramD - GET API ENTRY POINT
    AX = 1684h
    BX = 3099h (virtual device ID for VVidramD device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3501)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3501)
Call VVidramD (VIDRAM.VXD) virtual-86 entry point with:
    AX = function number
        0000h map page???
        BX = page number???
        Return: CF clear if successful
            CF set on error
        0001h ???
        Return: CF clear if successful
            CF set on error
        else
        Return: CF set
SeeAlso: #1989,#3499
--------W-2F1684BX30F6-----------------------
INT 2F P - MS Windows - WSVV - GET API ENTRY POINT
    AX = 1684h
    BX = 30F6h (virtual device ID for WSVV device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3499)
Call WSVV.VXD protected-mode entry point with:
    AX = function number
        ????
    Return: ???
SeeAlso: #3501,#1990
--------W-2F1684BX310E-----------------------
INT 2F - MS Windows - WPS - GET API ENTRY POINT
    AX = 1684h
    BX = 310Eh (virtual device ID for WPS device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #1990)
          0000h:0000h if the VxD does not support an API
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 1990)
Call WPS protected-mode entry point with:
    DX = function
        0000h get WPS.386 version
        Return: CF clear
            AX = version (AH = major, AL = minor)
        0001h get number of installed VxDs
        Return: CF clear
            AX = number of installed VxDs
        0002h get VxD characteristics
        AX = number of VxD
        ES:BX -> buffer for VxD characteristics structure (see #1991)
        Return: CF clear
            ES:BX buffer filled
SeeAlso: #3499,#1992

Format of WPS.386 VxD characteristics structure:
Offset    Size    Description    (Table 1991)
 00h    WORD    VxD ID number
 02h    BYTE    VxD minor version
 03h    BYTE    VxD major version
 04h    BYTE    DDK minor version
 05h    BYTE    DDK major version
 06h    WORD    flags
        bit 0: V86 API supported
        bit 1: PM API supported
        bit 2: services supported
 08h    DWORD    start order
 0Ch  9 BYTEs    ASCIZ VxD name
SeeAlso: #1990
--------W-2F1684BX31CF-----------------------
INT 2F - MS Windows - STAT.386 - GET API ENTRY POINT
    AX = 1684h
    BX = 31CFh (virtual device ID for STAT.386) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #1992)
          0000h:0000h if the VxD does not support an API
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 1992)
Call STAT.386 entry point with:
    AX = function
        0000h get version
        Return: AX = STAT.386 version (AH = major, AL = minor)
        0001h execute RDMSR/WRMSR/RDTSC
        BH = 00h
        BL = second opcode byte (30h=WRMSR,31h=RDTSC,32h=RDMSR)
        EDX:EDI = value to be written (for BL=30h)
        ECX = MSR number for RDMSR/WRMSR
        Return: EDX:EAX = value read (RDTSR/RDMSR only)
SeeAlso: #1990,#3502
--------W-2F1684BX34DC-----------------------
INT 2F - QEMM v8.01 - MAGNARAM VxD - GET API ENTRY POINT
    AX = 1684h
    BX = 34DCh (virtual device ID for MAGNARAM) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3502)
          0000h:0000h if the VxD does not support an API
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3502)
Call MAGNARAM MAGNA95.VXD protected-mode entry point with:
    AX = function number
        0000h get version and ???
        Return: AX = version (AH = major, AL = minor)
            CX = ???
                bit 0: ???
                bit 1: ???
        0001h get ???
        Return: CF clear
            DX:AX = ??? SHL 2
        0002h
        Return: CF clear if successful
                AX = ???
                DX = ???
            CF set on error
        0003h get ???
        Return: CF clear
            DX:AX = ??? SHL 2
        0004h ???
        Return: CF clear
            DX:AX = ???
        0005h ???
        Return: CF clear
            DX:AX = ???
        0006h ???
        Return: CF clear
            DX:AX = ???
        0007h ???
        Return: CF clear
            DX:AX = ???
        0008h ???
        Return: CF clear
            DX:AX = ???
        0009h ???
        Return: CF clear
            DX:AX = ???
        000Ah ???
        Return: CF clear
            DX:AX = ???
        000Bh get ???
        Return: CF clear
            DX:AX = ??? SHL 2
        000Ch get ???
        Return: CF clear
            DX:AX = ??? SHL 2
        000Dh get ???
        Return: CF clear
            DX:AX = ??? SHL 2
        000Eh get ???
        Return: CF clear
            AX = ???
            DX = ???
        000Fh get ???
        Return: CF clear
            DX:AX = ???
        0010h get ???
        Return: CF clear
            DX:AX = ???
        0011h get ???
        Return: CF clear
            DX:AX = ???
        0012h get ???
        Return: CF clear
            DX:AX = ???
        0013h get ???
        Return: CF clear
            DX:AX = ???
        0014h get ???
        Return: CF clear
            DX:AX = ???
        0015h get ???
        Return: CF clear
            DX:AX = ???
        else
        Return: CF set
SeeAlso: #1992,#1993
--------W-2F1684BX357E-----------------------
INT 2F - MS Windows - DSOUND - GET API ENTRY POINT
    AX = 1684h
    BX = 357Eh (virtual device ID for DSOUND device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"
----------2F1684BX377B-----------------------
INT 2F - MS Windows - MX1501HAD - GET API ENTRY POINT
    AX = 1684h
    BX = 377Bh (virtual device ID for MX1501HAD device)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #1993)
          0000h:0000h if the VxD does not support an API
Note:    The drivers VCMD95C.VXD and VCMD.386 are part of the driver disks
      provided with the chip-card-reader/keyboard combination MX 1501 HAD,
      produced by Cherry
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 1993)
Call CHERRY VCMD95C.VXD entry point with:
    AX = function
        0001h get version
        Return: AX = version number (0100h) (AH = major, AL = minor)
        0002h hook INT 09 (and 8???)
        0003h unhook INT 09 (and 8???)
        0004h get number of bytes in FIFO
        Return: AX = bytes in FIFO
        0005h get next FIFO-data
        Return: AX = data
            BL = port number
            BH = direction (1=in, 0=out)
            DX:CX = timestamp
        0006h clear FIFO
        0007h output byte
        DX = port number
        BL = keyboard command
        Return: data in FIFO (see #1995)
               (value, port, in/out, timestamp)
        0008h input byte
        DX = port number
        Return: data in FIFO (see #1995)
            (value, port, in/out, timestamp)
        0009h input byte immediately
        DX = port number
        Return: AX = data
        000Ah read next FIFO data (nondestructive)
        Return: AX = data
            BL = port number
            BH = direction (1=in, 0=out)
            DX:CX = timestamp
        000Bh get timestamp
        Return: DX:CX = timestamp (in ms)
        000Ch enable IRQ 1
        000Dh disable IRQ 1
        000Eh enable data retrieval
        Note:    Sets a flag in the internal mode-byte which
              tells the driver to recognize the data
        000Fh disable data retrieval
        Note:    resets a flag in the internal mode-byte
        0010h get retrieval mode
        Return: AX = current retrieval mode
        0011h set retrieval mode
        BX = new retrieval mode (see #1994)
        Return: AX = old retrieval mode
        0012h get command value
        Return: AX = command value
        0013h set command value
        BX = command value
SeeAlso: #1992,#3500

Bitfields for retrieval mode:
Bit(s)    Description    (Table 1994)
 0    enable data retrieval
 1    0 = interrupt-driven
    1 = polling mode
 2    0 = read port 60h everytime
    1 = read port 60h only when OBF of port 64h is set
 3    0 = don't call old INT 9
    1 = call INT 9 before our INT-handler
 4-7    reserved
SeeAlso: #1993,#1995

Structure of FIFO entry (1024 entries in FIFO):
Offset    Size    Description    (Table 1995)
 00h    BYTE    data byte
 01h    BYTE    I/O port
 02h    BYTE    direction (1=in, 0=out)
 03h    BYTE    reserved
 04h    DWORD    timestamp
SeeAlso: #1993,#1994
--------W-2F1684BX38DA-----------------------
INT 2F - MS Windows - VIWD - GET API ENTRY POINT
    AX = 1684h
    BX = 38DAh (virtual device ID for VIWD device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #3500)
          0000h:0000h if the VxD does not support API in current mode
SeeAlso: AX=1684h"DEVICE API",INT 20"Windows"

(Table 3500)
Call VIWD.VXD entry point with:
    DX = function number
        0000h ???
        Return: CF clear
            AX = ???
        0004h ???
        Return: CF clear
            DX = 0000h
        0006h
        Return: CF clear
        000Ah
        AX = ???
        Return: CF clear if successful
            CF set on error
        000Ch
        000Dh
        000Eh
        Return: CF clear
        000Fh
        Return: CF clear
        0010h
        0011h
        0015h
        Return: CF clear if successful
                AX = ???
            CF set on error
                AX = ???
            DX = 0000h
        0016h
        0017h
        Return: CF clear if successful
                AX = ???
            CF set on error
                AX = ???
            DX = 0000h
        0018h ???
        CX = ???
        Return: CF clear if successful
                AX = 0000h
            CF set on error
        else
        Return: CF set
SeeAlso: #1993,#1996
--------W-2F1684BX4321-----------------------
INT 2F - MS Windows - POSTMSG - GET API ENTRY POINT
    AX = 1684h
    BX = 4321h (virtual device ID for POSTMSG device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #1996,#1998)
          0000h:0000h if the VxD does not support an API

(Table 1996)
Call POSTMSG protected-mode entry point with:
    AX = window handle
    CX:BX -> callback procedure (see #1997)
Return: nothing
Note:    this call registers a WinApp with the VxD; the callback must be in a
      fixed, non-discardable code segment
SeeAlso: #1998,#1982

(Table 1997)
Values POSTMSG callback routine is called with:
    STACK:    DWORD    "lParam" parameter from DOSApp
        WORD    "wParam" parameter from DOSApp
        WORD    Windows message number (WM_USER + 100h)
        WORD    registered HWND

(Table 1998)
Call POSTMSG V86-mode entry point with:
    BX = wParam value to pass to protected-mode callback
    DX:AX = lParam value to pass to protected-mode callback
Return: CF clear if successful
    CF set on error (no WinApp registered)
SeeAlso: #1996
--------W-2F1684BX7FE0-----------------------
INT 2F - MS Windows - VSWITCHD - GET API ENTRY POINT
    AX = 1684h
    BX = 7FE0h (virtual device ID for VSWITCHD device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #1982)
          0000h:0000h if the VxD does not support an API

(Table 1982)
Call VSWITCHD entry point with:
    AX = function
        0000h toggle windowed mode (simulate Alt-Enter keypress)
        Return: nothing
        0001h get windowed mode
        Return: CF clear if VM is windowed
            CF set if VM is full-screen
SeeAlso: #1996,#1999
--------W-2F1684BX8888-----------------------
INT 2F - MS Windows - VbillD - GET API ENTRY POINT
    AX = 1684h
    BX = 8888h (virtual device ID for VbillD device) (see #1968)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point (see #1999)
          0000h:0000h if the VxD does not support an API

(Table 1999)
Call VbillD entry point with:
    AX = function
        0001h set reverse video
        0002h set normal video
Return: ???
SeeAlso: #1982
--------W-2F1685-----------------------------
INT 2F - MS Windows - SWITCH VMs AND CALLBACK
    AX = 1685h
    BX = VM ID of virtual machine to switch to
    CX = flags (see #2000)
    DX:SI = priority boost (refer to 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,AX=DB06h"WINGO"

Bitfields for VM switching flags:
Bit(s)    Description    (Table 2000)
 0    wait until interrupts enabled
 1    wait until critical section unowned
 2-15    reserved (zero)
--------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 (see #2001)
    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 D4/AH=10h

(Table 2001)
Call DPMI 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-2F1688BX0BAD-----------------------
INT 2F U - MS Windows 3.0, 386MAX v6.01 - GET ALIAS SELECTOR TO LDT
    AX = 1688h
    BX = 0BADh
Return: AX = 0000h if supported
        BX = alias selector for LDT
Note:    use the LSL instruction or GetSelectorLimit() to find LDT size
    this call should be considered obsolete for Windows 3.1+, as the
      alias selector can be retrieved via the API entry point for
      "MS-DOS" retrieved from INT 2F/AX=168Ah (see #2003)
--------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 (see #2002)
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

(Table 2002)
Values for DPMI vendor-specific API names:
 "MS-DOS"    MS Windows and 386MAX v6.00+ (see #2003)
 "386MAX"    386MAX v6.00+
 "HELIX_DPMI"    Helix Netroom's DPMI server
 "Phar Lap"    Phar Lap 286|DOS-Extender RUN286 (see #2004)
 "RATIONAL DOS/4G"  DOS/4G, DOS/4GW

(Table 2003)
Call Windows-support ("MS-DOS") entry point with:
    AX = 0100h get LDT alias selector
Return: CF clear if successful
        AX = alias selector
    CF set on error

(Table 2004)
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), 0000h for current DOS box
Return: AL = 00h if focus set to specified VM
Notes:    documented on the Microsoft Developer's Network CD-ROM
    if the VM is a windowed DOS box, it will be set to full screen
SeeAlso: AX=1683h
--------W-2F168C-----------------------------
INT 2F - MS Windows 3.1 - RESTART COMMAND
    AX = 168Ch
    ???
Return: ???
Note:    WIN.COM executes specified application
--------W-2F168EDX0000-----------------------
INT 2F - Windows95 - TITLE - SET APPLICATION TITLE
    AX = 168Eh
    DX = 0000h
    ES:DI -> ASCIZ application title (max 79 chars+NUL)
Return: AX = status
        0000h failed
        0001h successful
Note:    if ES:DI is 0000h:0000h or points at an empty string, the current
      title is removed
BUG:    this function can return a successful status even though the title was
      not changed; reportedly, waiting for two clock ticks after program
      startup solves this problem
SeeAlso: AX=168Eh/DX=0001h,AX=168Eh/DX=0002h
--------W-2F168EDX0001-----------------------
INT 2F - Windows95 - TITLE - SET VIRTUAL MACHINE TITLE
    AX = 168Eh
    DX = 0001h
    ES:DI -> ASCIZ virtual machine title (max 29 chars+NUL)
Return: AX = status
        0000h failed
        0001h successful
Notes:    if ES:DI is 0000h:0000h or points at an empty string, the current
      title is removed
    the VM title should only be changed on explicit instruction from the
      user
BUG:    this function can return a successful status even though the title was
      not changed; reportedly, waiting for two clock ticks after program
      startup solves this problem
SeeAlso: AX=168Eh/DX=0000h,AX=168Eh/DX=0003h
--------W-2F168EDX0002-----------------------
INT 2F - Windows95 - TITLE - GET APPLICATION TITLE
    AX = 168Eh
    DX = 0002h
    ES:DI -> buffer for ASCIZ application title
    CX = size of buffer in bytes
Return: AX = status
        0000h failed
        0001h successful
Desc:    copy as much of the application's window title as possible to the given
      buffer, appending a terminating NUL to the buffer
SeeAlso: AX=168Eh/DX=0000h,AX=168Eh/DX=0003h
--------W-2F168EDX0003-----------------------
INT 2F - Windows95 - TITLE - GET VIRTUAL MACHINE TITLE
    AX = 168Eh
    DX = 0003h
    ES:DI -> buffer for ASCIZ virtual-machine title
    CX = size of buffer in bytes
Return: AX = status
        0000h failed
        0001h successful
Desc:    copy as much of the virtual machine's title as possible to the given
      buffer, appending a terminating NUL to the buffer
SeeAlso: AX=168Eh/DX=0001h,AX=168Eh/DX=0002h
--------W-2F168FDH00-------------------------
INT 2F - Windows95 - CLOSE-AWARENESS - ENABLE/DISABLE CLOSE COMMAND
    AX = 168Fh
    DH = 00h
    DL = new state
        00h disabled
        01h enabled
Return: AX = status
        0000h successful
        else failed
Desc:    enable or disable the system menu Close command for an application
SeeAlso: AX=168Fh/DH=01h,AX=168Fh/DH=02h
--------W-2F168FDH01-------------------------
INT 2F - Windows95 - CLOSE-AWARENESS - QUERY CLOSE
    AX = 168Fh
    DH = 01h
    DL = 00h (reserved)
Return: AX = status
        0000h Close command selected but not yet acknowledged
        0001h Close command issued and acknowledged
        168Fh Close command not selected -- application should continue
Desc:    determine whether the user has requested that the application be closed
      by selecting the system menu's Close option
SeeAlso: AX=168Fh/DH=00h,AX=168Fh/DH=02h
--------W-2F168FDH02-------------------------
INT 2F - Windows95 - CLOSE-AWARENESS - ACKNOWLEDGE CLOSE
    AX = 168Fh
    DH = 02h
    DL = 00h (reserved)
Return: AX = status
        0000h successful
        else failed
Note:    once a Close command has been issued, no further keyboard input is
      available to the application until it calls this function to
      acknowledge the Close request
SeeAlso: AX=168Fh/DH=00h,AX=168Fh/DH=03h
--------W-2F168FDH03-------------------------
INT 2F - Windows95 - CLOSE-AWARENESS - CANCEL CLOSE
    AX = 168Fh
    DH = 03h
    DL = 00h (reserved)
Return: AX = status
        0000h successful
        else failed
Desc:    cancels a close request which has already been acknowledged if the
      application determines that it will not exit at this time
SeeAlso: AX=168Fh/DH=00h,AX=168Fh/DH=03h
--------D-2F1690-----------------------------
INT 2F U - MS-DOS 7 kernel - GET/SET ???
    AX = 1690h
    ES:BX -> ???
Return: ES:BX -> ??? data (see #3318)
SeeAlso: AX=1611h,AX=1614h

Format of MS-DOS 7 kernel ??? data:
Offset    Size    Description    (Table 3318)
 00h    DWORD    -> ??? data (appears to list the installed drivers)
 04h    DWORD    -> ??? (value passed in via ES:BX is stored here)
--------!---Section--------------------------