TopWare Tools/TOOLS.iso/tools/top1588/gepackt.exe/INTER33B/INTERRUP.E

Text File | 1993-01-03 | 232.9 KB | 6,441 lines

Interrupt List, part 5 of 8
This compilation is Copyright (c) 1989,1990,1991,1992,1993 Ralf Brown
----------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.
Note:    Since the multiplex chain is growing so long, and beginning to
      experience multiplex number collisions, I am proposing an alternate
      multiplex interrupt on INT 2D.  If you decide to use the alternate
      multiplex, please let me know.
SeeAlso: INT 2D
----------2F---------------------------------
INT 2F - BMB Compuscience Canada Utilities Interface
    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
----------2F---------------------------------
INT 2F - Ross Wentworth's Turbo Pascal POPUP LIBRARY
    AH = programmer-selected multiplex number
    AL = function
        00h installation check
        Return: AL = FFh if installed
        01h get TSR interrupt vectors
        Return: DX:AX -> vector table (see below)
        02h get TSR code segment
        Return: AX = code segment for all interrupt handlers
        03h call user exit routine and release TSR's memory
        04h get signature string
        Return: DX:AX -> counted string containing signature
        05h get TSR's INT 2F handler
        Return: DX:AX -> INT 2F handler
        06h enable/disable TSR
        BL = new state (00h disabled, 01h enabled)
        07h activate TSR (popup if not disabled)
        08h get hotkeys
        BL = which hotkey (00h = hotkey 1, 01h = hotkey 2)
        Return: AX = hotkey (AH = keyflags, AL = scancode)
        09h set hotkey
        BL = which hotkey (00h = hotkey 1, 01h = hotkey 2)
        CX = new hotkey (CH = keyflags, CL = scancode)
        0Ah-1Fh reserved

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

Format of author_name_ver table:
Offset    Size    Description
 -16    WORD    segment in which really begins the TSR code (CS in programs
        with PSP, XMS upper memory segment if installed as UMB...)
 -14    WORD    offset in which really begins the TSR code (frecuently 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 the unistall process).
 -10    BYTE    characteristics byte
        bits 0-2: 000 normal program (with PSP)
              001 upper XMS memory block (needed HIMEM.SYS function
                  to free memory when unistalling)
              010 device driver (*.SYS)
              011 device driver in EXE format
              1xx others (reserved)
        bits 3-6 reserved
        bit 7 set if extra_table defined and supported
 -9    BYTE    number of multiplex entry used (redefinition available). Note
        that the TSR must be use THIS variable in it's INT 2Fh handler.
 -8    WORD    offset to vector_area table (see bellow)
 -6    WORD    offset to extra_area table (see bit 7 in offset -10 and bellow)
 -4   4 BYTEs    "*##*"    (to insure that the TSR verify this agreement)
 00h    var    "AUTHOR:PROGRAM_NAME:VERSION",0     (variable length, this area
        is used in order to determine if the TSR is already resident
        and it's version code; the ':' char is used as delimiter)

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

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

Format of external_ctrl table:
Offset    Size    Description
 00h    BYTE    bit 0: TSR is relocatable (no absolute segment references)
 01h    WORD    offset to a variable which can activate/inhibit the TSR
 ---And if bit 0 in offset 00h is off:
 03h    DWORD    pointer to ASCIIZ with pathname to 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)
----------2F00-------------------------------
INT 2F U - DOS 2.x 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
----------2F0080-----------------------------
INT 2F - DOS 3.1+ PRINT.COM - GIVE PRINT A TIME SLICE
    AX = 0080h
Return: after PRINT executes
----------2F01-------------------------------
INT 2F U - DOS 2.x 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
----------2F0100-----------------------------
INT 2F - DOS 3+ PRINT.COM - INSTALLATION CHECK
    AX = 0100h
Return: AL = status
        00h not installed
        01h not installed, but not OK to install
        FFh installed
SeeAlso: AX=0101h
----------2F0101-----------------------------
INT 2F - DOS 3+ PRINT.COM - SUBMIT FILE FOR PRINTING
    AX = 0101h
    DS:DX -> submit packet (see below)
Return: CF clear if successful
        AL = 01h added to queue
         9Eh now printing
    CF set on error
        AX = error code (see also INT 21/AH=59h)
        01h invalid function
        02h file not found
        03h path not found
        04h out of file handles
        05h access denied
        08h print queue full
        09h spooler busy
        0Ch name too long
        0Fh invalid drive
SeeAlso: AX=0102h

Format of submit packet:
Offset    Size    Description
 00h    BYTE    level (must be 00h)
 01h    DWORD    pointer to ASCIZ filename (no wildcards)
----------2F0102-----------------------------
INT 2F - DOS 3+ PRINT.COM - REMOVE FILE FROM PRINT QUEUE
    AX = 0102h
    DS:DX -> ASCIZ filename (wildcards allowed)
Return: CF clear if successful
    CF set on error
        AX = error code (see AX=0101h)
SeeAlso: AX=0101h,AX=0103h
----------2F0103-----------------------------
INT 2F - DOS 3+ PRINT.COM - CANCEL ALL FILES IN PRINT QUEUE
    AX = 0103h
Return: CF clear if successful
    CF set on error
        AX = error code (see AX=0101h)
SeeAlso: AX=0102h
----------2F0104-----------------------------
INT 2F - DOS 3+ PRINT.COM - FREEZE PRINT QUEUE TO READ JOB STATUS
    AX = 0104h
Return: CF clear if successful
        DX = error count
        DS:SI -> print queue
    CF set on error
        AX = error code (see AX=0101h)
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
----------2F0105-----------------------------
INT 2F - DOS 3+ PRINT.COM - RESTART PRINT QUEUE AFTER STATUS READ
    AX = 0105h
Return: CF clear if successful
    CF set on error
        AX = error code (see AX=0101h)
SeeAlso: AX=0104h
----------2F0106-----------------------------
INT 2F - DOS 3.3+ PRINT.COM - GET PRINTER DEVICE
    AX = 0106h
Return: CF set if files in print queue
        AX = error code 0008h (queue full)
        DS:SI -> device driver header
    CF clear if print queue empty
        AX = 0000h
Note:    documented for DOS 5+, but not documented for prior versions
SeeAlso: AX=0104h
----------2F0200-----------------------------
INT 2F U - PC LAN PROGRAM REDIR/REDIRIFS internal - INSTALLATION CHECK
    AX = 0200h
Return: AL = FFh if installed
----------2F0201-----------------------------
INT 2F U - PC LAN PROGRAM REDIR/REDIRIFS internal - ???
    AX = 0201h
Return: nothing???
Notes:    called by DOS 3.3+ PRINT.COM
    AX=0202h appears to be the opposite function
SeeAlso: AX=0202h
----------2F0202-----------------------------
INT 2F U - PC LAN PROGRAM REDIR/REDIRIFS internal - ???
    AX = 0202h
    ???
Return: nothing???
Note:    called by DOS 3.3+ PRINT.COM
SeeAlso: AX=0201h
----------2F0203-----------------------------
INT 2F U - PC LAN PROGRAM REDIR/REDIRIFS internal - ???
    AX = 0203h
Return: nothing???
Notes:    called by DOS 3.3+ PRINT.COM
    AX=0204h appears to be the opposite function
SeeAlso: AX=0204h
----------2F0204-----------------------------
INT 2F U - PC LAN PROGRAM REDIR/REDIRIFS internal - ???
    AX = 0204h
    ???
Return: nothing???
Note:    called by DOS 3.3 PRINT.COM
----------2F---------------------------------
INT 2F U - PC LAN PROGRAM REDIR/REDIRIFS internal - ???
    AX = 02xxh
    ???
Return: ???
----------2F0500-----------------------------
INT 2F U - DOS 3+ CRITICAL ERROR HANDLER - INSTALLATION CHECK
    AX = 0500h
Return: AL = 00h not installed, OK to install
         01h not installed, can't install
         FFh installed
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
----------2F05-------------------------------
INT 2F UC - DOS 3+ CRITICAL ERROR HANDLER - EXPAND ERROR INTO STRING
    AH = 05h
---DOS 3.x---
    AL = extended error code (not zero)
---DOS 4+ ---
    AL = error type
        01h DOS extended error code
        02h parameter error
    BX = error code
Return: CF clear if successful
        ES:DI -> ASCIZ error message (read-only)
        AL = ???
    CF set if error code can't be converted to string
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 message
    subfunction 02h called by many DOS 4 external programs
SeeAlso: AX=122Eh,INT 24
----------2F0600-----------------------------
INT 2F - DOS 3+ ASSIGN - INSTALLATION CHECK
    AX = 0600h
Return: AL = status
        00h not installed
        01h not installed, but not OK to install
        FFh installed
Notes:    ASSIGN is not a TSR in DR-DOS 5.0; it is internally replaced by SUBST
      (see INT 21/AH=52h)
    undocumented prior to the release of DOS 5.0
SeeAlso: AX=0601h,INT 21/AH=52h
----------2F0601-----------------------------
INT 2F U - DOS 3+ ASSIGN - GET DRIVE ASSIGNMENT TABLE
    AX = 0601h
Return: ES = segment of ASSIGN work area and assignment table
Note:    under DOS 3+, the 26 bytes starting at ES:0103h specify which drive
      each of A: to Z: is mapped to.  Initially set to 01h 02h 03h....
SeeAlso: AX=0600h
----------2F0800-----------------------------
INT 2F U - DRIVER.SYS support - INSTALLATION CHECK
    AX = 0800h
Return:    AL = 00h not installed, OK to install
         01h not installed, not OK to install
         FFh installed
Note:    supported by DR-DOS 5.0
----------2F0801-----------------------------
INT 2F U - DRIVER.SYS support - ADD NEW BLOCK DEVICE
    AX = 0801h
    DS:DI -> drive data table (see AX=0803h)
Notes:    moves down internal list of drive data tables, copying and modifying
      the drive description flags word for tables referencing same physical
      drive
    data table appended to chain of tables
    supported by DR-DOS 5.0
SeeAlso: AX=0803h
----------2F0802-----------------------------
INT 2F U - DRIVER.SYS support - EXECUTE DEVICE DRIVER REQUEST
    AX = 0802h
    ES:BX -> device driver request header (see below)
Return: request header updated as per requested operation
Notes:    supported by DR-DOS 5.0
    DOS 3.2 executes this function on any AL value from 02h through F7h
SeeAlso: AX=0800h,AX=0801h,AX=0803h,INT 21/AH=52h,INT 21/AH=99h,INT 21/AH=9Ah

Values for command code:
    00h INIT
    01h MEDIA CHECK (block devices)
    02h BUILD BPB (block devices)
    03h IOCTL INPUT
    04h INPUT
    05h NONDESTRUCTIVE INPUT, NO WAIT (character devices)
    06h INPUT STATUS (character devices)
    07h INPUT FLUSH (character devices)
    08h OUTPUT
    09h OUTPUT WITH VERIFY
    0Ah OUTPUT STATUS (character devices)
    0Bh OUTPUT FLUSH (character devices)
    0Ch IOCTL OUTPUT
    0Dh (DOS 3+) DEVICE OPEN
    0Eh (DOS 3+) DEVICE CLOSE
    0Fh (DOS 3+) REMOVABLE MEDIA (block devices)
    10h (DOS 3+) OUTPUT UNTIL BUSY (character devices)
    11h (European MSDOS 4.0) STOP OUTPUT (console screen drivers only)
    12h (European MSDOS 4.0) RESTART OUTPUT (console screen drivers only)
    13h (DOS 3.2+) GENERIC IOCTL
    14h unused
    15h (European MSDOS 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

Format of device driver request header:
Offset    Size    Description
 00h    BYTE    length of request header
 01h    BYTE    subunit within device driver
 02h    BYTE    command code (see above)
 03h    WORD    status (filled in by device driver)
        bit 15: error
        bits 14-11: reserved
        bit 10: ??? set by DOS kernel on entry to some driver calls
        bit 9: busy
        bit 8: done (may be clear on return under European MSDOS 4.0)
        bits 7-0: error code if bit 15 set (see below)
---DOS---
 05h  4 BYTEs    reserved (unused in DOS 2.x and 3.x)
 09h    DWORD    (European MSDOS 4.0 only) pointer to next request header in
            device's request queue
        (other versions) reserved (unused in DOS 2.x and 3.x)
---STARLITE architecture---
 05h    DWORD    pointer to next request header
 09h  4 BYTEs    reserved
---command code 00h---
 0Dh    BYTE    (return) number of units
 0Eh    DWORD    (call) pointer to DOS device helper function (see below)
            (European MSDOS 4.0 only)
        (call) pointer past end of memory available to driver (DOS 5.0)
        (return) address of first free byte following driver
 12h    DWORD    (call) pointer to commandline arguments
        (return) pointer to BPB array (block drivers) or
                0000h:0000h (character drivers)
 16h    BYTE    (DOS 3+) drive number for first unit of block driver (0=A)
   ---European MSDOS 4.0---
 17h    DWORD    pointer to function to save registers on stack
   ---DOS 5.0---
 17h    WORD    (return) error-message flag
            0001h MSDOS should display error msg on init failure
---command code 01h---
 0Dh    BYTE    media descriptor
 0Eh    BYTE    returned status
        00h don't know
        01h media has not changed
        FFh media has been changed
 0Fh    DWORD    (return, DOS 3+) pointer to previous volume ID if OPEN/CLOSE/RM
          bit in device header is set and disk changed
---command code 02h---
 0Dh    BYTE    media descriptor
 0Eh    DWORD    transfer address
        -> scratch sector if NON-IBM FORMAT bit in device header set
        -> first FAT sector otherwise
 12h    DWORD    pointer to BPB (set by driver) (see INT 21/AH=53h)
---command codes 03h,0Ch--- (see also INT 21/AX=4402h,INT 21/AX=4403h)
 0Dh    BYTE    media descriptor (block devices only)
 0Eh    DWORD    transfer address
 12h    WORD    (call) number of bytes to read/write
        (return) actual number of bytes read or written
---command codes 04h,08h,09h---
 0Dh    BYTE    media descriptor (block devices only)
 0Eh    DWORD    transfer address
 12h    WORD    byte count (character devices) or sector count (block devices)
 14h    WORD    starting sector number (block devices only)
 16h    DWORD    (DOS 3+) pointer to volume ID if error 0Fh returned
 1Ah    DWORD    (DOS 4+) 32-bit starting sector number (block devices with
        device attribute word bit 1 set only) (see INT 21/AH=52h)
---command code 05h---
 0Dh    BYTE    byte read from device if BUSY bit clear on return
---command codes 06h,07h,0Ah,0Bh,0Dh,0Eh,0Fh---
 no further fields
---command code 10h---
 0Dh    BYTE    unused
 0Eh    DWORD    transfer address
 12h    WORD    (call) number of bytes to write
        (return) actual number of bytes written
---command codes 11h,12h---
 0Dh    BYTE    reserved
---command code 15h---
 no further fields
---command codes 13h,19h---
 0Dh    BYTE    category code
        00h unknown
        01h COMn:
        03h CON
        05h LPTn:
        07h mouse (European MSDOS 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 MSDOS 4.0)
 11h    WORD    offset of device driver header
        DI contents (European MSDOS 4.0)
 13h    DWORD    pointer to parameter block from INT 21/AX=440Ch or AX=440Dh
---command codes 80h,82h---
 0Dh    BYTE    addressing mode
        00h HSG (default)
        01h Phillips/Sony Red Book
 0Eh    DWORD    transfer address (ignored for command 82h)
 12h    WORD    number of sectors to read
        (if 0 for command 82h, request is an advisory seek)
 14h    DWORD    starting sector number
        logical sector number in HSG mode
        frame/second/minute/unused in Red Book mode
        (HSG sector = minute * 4500 + second * 75 + frame - 150)
 18h    BYTE    data read mode
        00h cooked (2048 bytes per frame)
        01h raw (2352 bytes per frame, including EDC/ECC)
 19h    BYTE    interleave size (number of sectors stored consecutively)
 1Ah    BYTE    interleave skip factor (# sectors between consec portions)
---command code 83h---
 0Dh    BYTE    addressing mode (see above)
 0Eh    DWORD    transfer address (ignored)
 12h    WORD    number of sectors to read (ignored)
 14h    DWORD    starting sector number (see also above)
---command code 84h---
 0Dh    BYTE    addressing mode (see above)
 0Eh    DWORD    starting sector number (see also above)
 12h    DWORD    number of sectors to play
---command codes 85h,88h---
 no further fields
---command codes 86h,87h---
 0Dh    BYTE    addressing mode (see above)
 0Eh    DWORD    transfer address (ignored in write mode 0)
 12h    WORD    number of sectors to write
 14h    DWORD    starting sector number (see also above)
 18h    BYTE    write mode
        00h mode 0 (write all zeros)
        01h mode 1 (default) (2048 bytes per sector)
        02h mode 2 form 1 (2048 bytes per sector)
        03h mode 2 form 2 (2336 bytes per sector)
 19h    BYTE    interleave size (number of sectors stored consecutively)
 1Ah    BYTE    interleave skip factor (# sectors between consec portions)

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

Call European MSDOS 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 = interruptible flag (nonzero if pause may be interrupted)
        interrupts disabled
        Return:    after corresponding ProcRun call
            CF clear if event wakeup, set if unusual wakeup
            ZF set if timeout wakeup, clear if interrupted
            AL = wakeup code, nonzero if unusual wakeup
            interrupts enabled
            BX,CX,DX destroyed
        Note:    block process and schedules another to run
        0Ah "ProcRun" unblock process
        AX:BX = event identifier (typically a pointer)
        Return:    AX = number of processes awakened
            ZF set if no processes awakened
            BX,CX,DX destroyed
        0Bh "QueueInit" initialize/clear character queue
        DS:BX -> character queue structure (see below)
        Note:    the queue size field must be set before calling
        0Dh "QueueWrite" put a character in the queue
        DS:BX -> character queue (see below)
        AL = character to append to end of queue
        Return: ZF set if queue is full
            ZF clear if character stored
        0Eh "QueueRead" get a character from the queue
        DS:BX -> character queue (see below)
        Return: ZF set if queue is empty
            ZF clear if characters in queue
                AL = first character in queue
        10h "GetDOSVar" return pointer to DOS variable
        AL = index of variable
            03h current process ID
        BX = index into variable if AL specifies an array
        CX = expected length of variable
        Return: CF clear if successful
                DX:AX -> variable
            CF set on error
                AX,DX destroyed
            BX,CX destroyed
        Note:    the variables may not be modified
        14h "Yield" yield CPU if higher-priority task ready to run
        Return: FLAGS destroyed
        1Bh "CritEnter" begin system critical section
        DS:BX -> semaphore (6 BYTEs, initialized to zero)
        Return: AX,BX,CX,DX destroyed
        1Ch "CritLeave" end system critical section
        DS:BX -> semaphore (6 BYTEs, initialized to zero)
        Return: AX,BX,CX,DX destroyed
        Note:    must be called in the context of the process which
              called CritEnter on the semaphore
Note:    the DWORD pointing at the request queue must be allocated by the driver
      and initialized to 0000h:0000h.  It always points at the next request
      to be executed

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

Format of DOS 3.30 drive data table:
Offset    Size    Description
 00h    DWORD    pointer to next table
 04h    BYTE    physical unit number (for INT 13)
 05h    BYTE    logical drive number
 06h 19 BYTEs    BIOS Parameter Block (see also INT 21/AH=53h)
        Offset    Size    Description
         00h    WORD    bytes per sector
         02h    BYTE    sectors per cluster, FFh if unknown
         03h    WORD    number of reserved sectors
         05h    BYTE    number of FATs
         06h    WORD    number of root dir entries
         08h    WORD    total sectors
         0Ah    BYTE    media descriptor, 00h if unknown
         0Bh    WORD    sectors per FAT
         0Dh    WORD    sectors per track
         0Fh    WORD    number of heads
         11h    WORD    number of hidden sectors
 19h    BYTE    flags
        bit 6: 16-bit FAT instead of 12-bit FAT
 1Ah    WORD    number of DEVICE OPEN calls without corresponding DEVICE CLOSE
 1Ch 11 BYTEs    volume label or "NO NAME    " if none (always "NO NAME" for
        fixed media)
 27h    BYTE    terminating null for volume label???
 28h    BYTE    device type (see INT 21/AX=440Dh)
 29h    WORD    bit flags describing drive
        bit 0: fixed media
        bit 1: door lock supported
        bit 2: ??? (used in determining BPB to set for INT 21/AX=440Dh)
        bit 3: all sectors in a track are the same size
        bit 4: physical drive has multiple logical units
        bit 5: current logical drive for physical drive
        bit 6: ???
        bit 7: ???
        bit 8: ??? (related to disk change detection)
 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 MSDOS 3.30 fixed media, nulls for removable
        media and PCDOS 3.30)
 4Ch    BYTE    least-significant byte of last-accessed cylinder number
---removable media---
 4Dh    DWORD    time of last access in clock ticks (FFFFFFFFh if never)
---fixed media---
 4Dh    WORD    partition (FFFFh = primary, 0001h = extended)
 4Fh    WORD    absolute cylinder number of partition's start on physical
        drive (always FFFFh if primary partition)

Format of COMPAQ DOS 3.31 drive data table:
Offset    Size    Description
 00h    DWORD    pointer to next table
 04h    BYTE    physical unit number (for INT 13)
 05h    BYTE    logical drive number
 06h 25 BYTEs    BIOS Parameter Block (see DOS 4.0-5.0 drive data table below)
 1Fh  6 BYTEs    ??? apparently always zeros
 25h    BYTE    flags
        bit 6: 16-bit FAT instead of 12-bit FAT
            5: large volume???
 26h    WORD    device-open count???
 28h 11 BYTEs    volume label or "NO NAME    " if none (always "NO NAME" for
        fixed media)
 33h    BYTE    terminating null for volume label
 34h    BYTE    device type (see INT 21/AX=440Dh)
 35h    WORD    bit flags describing drive
 37h    WORD    number of cylinders
 39h 25 BYTEs    BIOS parameter block for highest capacity drive supports
 52h  6 BYTEs    ??? apparently always zeros
 58h    BYTE    least-significant byte of last-accessed cylinder number
---removable media---
 59h    DWORD    time of last access in clock ticks (FFFFFFFFh if never)
---fixed media---
 59h    WORD    partition (FFFFh = primary, 0001h = extended)
 5Bh    WORD    absolute cylinder number of partition's start on physical
        drive (always FFFFh if primary partition)

Format of DOS 4.0-5.0 drive data table:
Offset    Size    Description
 00h    DWORD    pointer to next table
 04h    BYTE    physical unit number (for INT 13)
 05h    BYTE    logical drive number
 06h 25 BYTEs    BIOS Parameter Block (see also INT 21/AH=53h)
        Offset    Size    Description
         00h    WORD    bytes per sector
         02h    BYTE    sectors per cluster, FFh if unknown
         03h    WORD    number of reserved sectors
         05h    BYTE    number of FATs
         06h    WORD    number of root dir entries
         08h    WORD    total sectors (see offset 15h if zero)
         0Ah    BYTE    media descriptor, 00h if unknown
         0Bh    WORD    sectors per FAT
         0Dh    WORD    sectors per track
         0Fh    WORD    number of heads
         11h    DWORD    number of hidden sectors
         15h    DWORD    total sectors if WORD at 08h is zero
 1Fh    BYTE    flags
        bit 6: 16-bit FAT instead of 12-bit
 20h  2 BYTEs    ???
 22h    BYTE    device type (see INT 21/AX=440Dh)
 23h    WORD    bit flags describing drive
        bit 0: fixed media
        bit 1: door lock supported
        bit 2: ???
        bit 3: all sectors in a track are the same size
        bit 4: physical drive has multiple logical units
        bit 5: current logical drive for physical drive
        bit 6: ???
        bit 7: ???
        bit 8: ???
 25h    WORD    number of cylinders
 27h 25 BYTEs    BIOS Parameter Block for highest capacity supported
 40h  7 BYTEs    ???
---removable media---
 47h    DWORD    time of last access in clock ticks (FFFFFFFFh if never)
---fixed media, DOS 4.x---
 47h    WORD    partition (FFFFh = primary, 0001h = extended)
 49h    WORD    absolute cylinder number of partition's start on phys drive
        (FFFFh if primary partition)
---fixed media, DOS 5.0---
 47h    WORD    ??? apparently always 0001h
 49h    WORD    absolute cylinder number of partition's start on phys drive
------
 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???
----------2F1000-----------------------------
INT 2F - SHARE - INSTALLATION CHECK
    AX = 1000h
Return: AL = 00h  not installed, OK to install
         01h  not installed, not OK to install
         FFh  installed
BUGS:    values of AL other than 00h put DOS 3.x SHARE into an infinite loop
      (08E9: OR  AL,AL
       08EB: JNZ 08EB) <- the buggy instruction (DOS 3.3)
    values of AL other than described here put PCDOS 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 5.0 chains to the previous handler if AL <> 00h on entry
SeeAlso: AX=1080h,INT 21/AH=52h
----------2F1001-----------------------------
INT 2F U - SuperStor PRO SSTORDRV.SYS - SET ???
    AX = 1001h
    BX = ???
    DX = ???
Program: SuperStor is a disk-compression program by Addstor.
SeeAlso: AX=F800h
----------2F1040-----------------------------
INT 2F U - DOS 4 only SHARE internal - ???
    AX = 1040h
    ???
Return: AL = FFh???
SeeAlso: AX=1000h
----------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
----------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
----------2F10FF-----------------------------
INT 2F U - Multiplex - DR-DOS 5.0 - ???
    AX = 10FFh
    ES:BX -> ???
Note:    sets pointer in kernel
----------2F1100-----------------------------
INT 2F C - NETWORK REDIRECTOR - INSTALLATION CHECK
    AX = 1100h
Return: AL = 00h  not installed, OK to install
         01h  not installed, not OK to install
         FFh  installed
Notes:    called by 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 5.0 moves the calls back into the
      redirector
----------2F1100-----------------------------
INT 2F - MSCDEX (MS CD-ROM Extensions) - INSTALLATION CHECK
    AX = 1100h
    STACK: WORD DADAh
Return: AL = 00h not installed, OK to install
        STACK unchanged
       = 01h not installed, not OK to install
        STACK unchanged
       = FFh installed
        STACK: WORD ADADh
----------2F1101-----------------------------
INT 2F CU - NETWORK REDIRECTOR - REMOVE REMOTE DIRECTORY
    AX = 1101h
    SS = DOS DS
    SDA first filename pointer -> fully-qualified directory name
    SDA CDS pointer -> current directory structure for drive with dir
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
Note:    called by DOS 3.1+ kernel
SeeAlso: AX=1103h,AX=1105h,INT 21/AH=3Ah,INT 21/AH=60h
----------2F1102-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - REMOVE REMOTE DIRECTORY
    AX = 1102h
    SS = DOS DS
    SDA first filename pointer -> fully-qualified directory name
    SDA CDS pointer -> current directory structure for drive with dir
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
Note:    appears to be identical to AX=1101h
SeeAlso: AX=1101h
----------2F1103-----------------------------
INT 2F CU - NETWORK REDIRECTOR - MAKE REMOTE DIRECTORY
    AX = 1103h
    SS = DOS DS
    SDA first filename pointer -> fully-qualified directory name
    SDA CDS pointer -> current directory structure for drive with dir
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
Note:    called by DOS 3.1+ kernel
SeeAlso: AX=1101h,AX=1105h,INT 21/AH=39h,INT 21/AH=60h
----------2F1104-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - MAKE REMOTE DIRECTORY
    AX = 1104h
    SS = DOS DS
    SDA first filename pointer -> fully-qualified directory name
    SDA CDS pointer -> current directory structure for drive with dir
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
Note:    appears to be identical to AX=1103h
SeeAlso: AX=1103h
----------2F1105-----------------------------
INT 2F CU - NETWORK REDIRECTOR - CHDIR
    AX = 1105h
    SS = DOS DS
    SDA first filename pointer -> fully-qualified directory name
    SDA CDS pointer -> current directory structure for drive with dir
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
        CDS updated with new path
Notes:    called by 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
----------2F1106-----------------------------
INT 2F CU - NETWORK REDIRECTOR - CLOSE REMOTE FILE
    AX = 1106h
    ES:DI -> SFT
        SFT DPB field -> DPB of drive containing file
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
        SFT updated (redirector must decrement open count, which may be
            done with INT 2F/AX=1208h)
Note:    called by DOS 3.1+ kernel
SeeAlso: AX=1201h,AX=1208h,AX=1227h,INT 21/AH=3Eh
----------2F1107-----------------------------
INT 2F CU - NETWORK REDIRECTOR - COMMIT REMOTE FILE
    AX = 1107h
    ES:DI -> SFT
        SFT DPB field -> DPB of drive containing file
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
        all buffers for file flushed
        directory entry updated
Note:    called by DOS 3.1+ kernel
SeeAlso: INT 21/AH=68h,INT 21/AX=5D01h
----------2F1108-----------------------------
INT 2F CU - NETWORK REDIRECTOR - READ FROM REMOTE FILE
    AX = 1108h
    ES:DI -> SFT
        SFT DPB field -> DPB of drive containing file
    CX = number of bytes
    SS = DOS DS
    SDA DTA field -> user buffer
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
        CX = number of bytes read (0000h = end of file)
        SFT updated
Note:    called by DOS 3.1+ kernel
SeeAlso: AX=1109h,AX=1229h,INT 21/AH=3Fh,INT 21/AX=5D06h
----------2F1109-----------------------------
INT 2F CU - NETWORK REDIRECTOR - WRITE TO REMOTE FILE
    AX = 1109h
    ES:DI -> SFT
        SFT DPB field -> DPB of drive containing file
    CX = number of bytes
    SS = DOS DS
    SDA DTA field -> user buffer
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
        CX = number of bytes written
        SFT updated
Note:    called by DOS 3.1+ kernel
SeeAlso: AX=1107h,AX=1108h,INT 21/AH=40h,INT 21/AX=5D06h
----------2F110A-----------------------------
INT 2F CU - NETWORK REDIRECTOR (DOS 3.x only) - LOCK REGION OF FILE
    AX = 110Ah
    BX = file handle
    CX:DX = starting offset
    SI = high word of size
    STACK: WORD low word of size
    ES:DI -> SFT
        SFT DPB field -> DPB of drive containing file
    SS = DOS DS
Return: CF set on error
       AL = DOS error code (see INT 21/AH=59h)
    STACK unchanged
Notes:    called by DOS 3.10-3.31 kernel
    the redirector is expected to resolve lock conflicts
SeeAlso: AX=110Bh,INT 21/AH=5Ch
----------2F110A-----------------------------
INT 2F CU - NETWORK REDIRECTOR (DOS 4+) - LOCK/UNLOCK REGION OF FILE
    AX = 110Ah
    BL = function
        00h lock
        01h unlock
    DS:DX -> parameter block (see below)
    ES:DI -> SFT
        SFT DPB field -> DPB of drive containing file
    SS = DOS DS
Return: CF set on error
       AL = DOS error code (see INT 21/AH=59h)
Notes:    called by DOS 4.0+ kernel
    the redirector is expected to resolve lock conflicts
SeeAlso: AX=110Bh,INT 21/AH=5Ch

Format of parameter block:
Offset    Size    Description
 00h    DWORD    start offset
 04h    DWORD    size of region
----------2F110B-----------------------------
INT 2F CU - NETWORK REDIRECTOR (DOS 3.x only) - UNLOCK REGION OF FILE
    AX = 110Bh
    BX = file handle
    CX:DX = starting offset
    SI = high word of size
    STACK: WORD low word of size
    ES:DI -> SFT for file
        SFT DPB field -> DPB of drive containing file
Return: CF set on error
       AL = DOS error code (see INT 21/AH=59h)
    STACK unchanged
Note:    called by DOS 3.1-3.31 kernel; DOS 4.0+ calls AX=110Ah instead
SeeAlso: AX=110Ah,INT 21/AH=5Ch
----------2F110C-----------------------------
INT 2F CU - NETWORK REDIRECTOR - GET DISK SPACE
    AX = 110Ch
    ES:DI -> current directory structure for desired drive
Return: AL = sectors per cluster
    AH = media ID byte
    BX = total clusters
    CX = bytes per sector
    DX = number of available clusters
Note:    called by DOS 3.1+ kernel
SeeAlso: INT 21/AH=36h
----------2F110D-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - ???
    AX = 110Dh
    SDA first filename pointer -> name of file
    ???
Return: ???
Note:    appears to be similar to AX=110Fh
SeeAlso: AX=110Fh
----------2F110E-----------------------------
INT 2F CU - NETWORK REDIRECTOR - SET REMOTE FILE'S ATTRIBUTES
    AX = 110Eh
    SS = DOS DS
    SDA first filename pointer -> fully-qualified name of file
    SDA CDS pointer -> current directory structure for drive with file
    STACK: WORD new file attributes
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
    STACK unchanged
Note:    called by DOS 3.1+ kernel
SeeAlso: AX=110Fh,INT 21/AX=4301h,INT 21/AH=60h
----------2F110F-----------------------------
INT 2F CU - NETWORK REDIRECTOR - GET REMOTE FILE'S ATTRIBUTES AND SIZE
    AX = 110Fh
    SS = DOS DS
    SDA first filename pointer -> fully-qualified name of file
    SDA CDS pointer -> current directory structure for drive with file
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
        AX = file attributes
        BX:DI = file size
Note:    called by DOS 3.1+ kernel
SeeAlso: AX=110Eh,INT 21/AX=4300h,INT 21/AH=60h
----------2F1110-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - ???
    AX = 1110h
    SDA first filename pointer -> name of file
    ???
Return: ???
Note:    appears to be similar to AX=110Eh
SeeAlso: AX=110Eh
----------2F1111-----------------------------
INT 2F CU - NETWORK REDIRECTOR - RENAME REMOTE FILE
    AX = 1111h
    SS = DS = DOS DS
    SDA first filename pointer = offset of fully-qualified old name
    SDA second filename pointer = offset of fully-qualified new name
    SDA CDS pointer -> current directory structure for drive with file
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
Note:    called by DOS 3.1+ kernel
SeeAlso: INT 21/AH=56h,INT 21/AH=60h
----------2F1112-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - ???
    AX = 1112h
    SS = DS = DOS DS
    SDA first filename pointer -> name of file
    ???
Return: ???
SeeAlso: AX=1111h
----------2F1113-----------------------------
INT 2F CU - NETWORK REDIRECTOR - DELETE REMOTE FILE
    AX = 1113h
    SS = DS = DOS DS
    SDA first filename pointer -> fully-qualified filename in DOS DS
    SDA CDS pointer -> current directory structure for drive with file
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
Notes:    called by DOS 3.1+ kernel
    the filespec may contain wildcards
SeeAlso: INT 21/AH=41h,INT 21/AH=60h
----------2F1114-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - ???
    AX = 1114h
    SDA first filename pointer -> name of file
    ???
Return: ???
SeeAlso: AX=1113h
----------2F1115-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - ???
    AX = 1115h
    SS = DOS DS
    ES:DI -> SFT ???
    ???
Return: ???
SeeAlso: AX=112Eh
----------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 open mode (see INT 21/AH=3Dh)
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
        SFT filled (except handle count, which DOS manages itself)
    STACK unchanged
Note:    called by DOS 3.1+ kernel
SeeAlso: AX=1106h,AX=1117h,AX=1118h,AX=112Eh,INT 21/AH=3Dh,INT 21/AH=60h
----------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
            high byte = 00h normal create, 01h create new file
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
        SFT filled (except handle count, which DOS manages itself)
    STACK unchanged
Note:    called by DOS 3.1+ kernel
SeeAlso: AX=1106h,AX=1116h,AX=1118h,AX=112Eh,INT 21/AH=3Ch,INT 21/AH=60h
----------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:    called by 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
----------2F1119-----------------------------
INT 2F CU - NETWORK REDIRECTOR - FIND FIRST FILE WITHOUT CDS
    AX = 1119h
    SS = DS = DOS DS
    [DTA] = uninitialized 21-byte findfirst search data (see INT 21/AH=4Eh)
    SDA first filename pointer -> fully-qualified search template
    SDA search attribute = attribute mask for search
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
        [DTA] = updated findfirst search data
            (bit 7 of first byte must be set)
        [DTA+15h] = standard directory entry for file
Notes:    called by DOS 3.1+ kernel
    DOS 4.x IFSFUNC returns CF set, AX=0003h
----------2F111A-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - ???
    AX = 111Ah
    ???
Return: CF set
        AX = error code (03h for DOS 4.01 IFSFUNC)
----------2F111B-----------------------------
INT 2F CU - NETWORK REDIRECTOR - FINDFIRST
    AX = 111Bh
    SS = DS = DOS DS
    [DTA] = uninitialized 21-byte findfirst search data (see INT 21/AH=4Eh)
    SDA first filename pointer -> fully-qualified search template
    SDA CDS pointer -> current directory structure for drive with file
    SDA search attribute = attribute mask for search
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
        [DTA] = updated findfirst search data
            (bit 7 of first byte must be set)
        [DTA+15h] = standard directory entry for file
Note:    called by DOS 3.1+ kernel
SeeAlso: AX=111Ch,INT 21/AH=4Eh,INT 21/AH=60h
----------2F111C-----------------------------
INT 2F CU - NETWORK REDIRECTOR - FINDNEXT
    AX = 111Ch
    SS = DS = DOS DS
    [DTA] = 21-byte findfirst search data (see INT 21/AH=4Eh)
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
        [DTA] = updated findfirst search data
            (bit 7 of first byte must be set)
        [DTA+15h] = standard directory entry for file
Note:    called by DOS 3.1+ kernel
SeeAlso: AX=111Bh,INT 21/AH=4Fh
----------2F111D-----------------------------
INT 2F CU - NETWORK REDIRECTOR - CLOSE ALL REMOTE FILES FOR PROCESS
    AX = 111Dh
    DS???
    SS = DOS DS
Return: ???
Notes:    called by DOS 3.1+ kernel
    closes all FCBs opened by process
SeeAlso: INT 21/AX=5D04h
----------2F111E-----------------------------
INT 2F CU - NETWORK REDIRECTOR - DO REDIRECTION
    AX = 111Eh
    SS = DOS DS
    STACK: WORD function to execute
        5F00h  get redirection mode
            BL = type (03h printer, 04h disk)
            Return: BH = state (00h off, 01h on)
        5F01h  set redirection mode
            BL = type (03h printer, 04h disk)
            BH = state (00h off, 01h on)
        5F02h  get redirection list entry
            BX = redirection list index
            DS:SI -> 16-byte local device name buffer
            ES:DI -> 128-byte network name buffer
            Return: must set user's BX to device type and CX to
                stored parameter value, using AX=1218h to get
                stack frame address
        5F03h  redirect device
            BL = device type (see INT 21/AX=5F03h)
            CX = stored parameter value
            DS:SI -> ASCIZ source device name
            ES:DI -> destination ASCIZ network path + ASCIZ passwd
        5F04h  cancel redirection
            DS:SI -> ASCIZ device name or network path
        5F05h  get redirection list extended entry
            BX = redirection list index
            DS:SI -> buffer for ASCIZ source device name
            ES:DI -> buffer for destination ASCIZ network path
            Return: BH = status flag
                BL = type (03h printer, 04h disk)
                CX = stored parameter value
                BP = NETBIOS local session number
        5F06h  similar to 5F05h???
Return: CF set on error
        AX = error code (see INT 21/AH=59h)
    STACK unchanged
Note:    called by DOS 3.1+ kernel
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
----------2F111F-----------------------------
INT 2F CU - NETWORK REDIRECTOR - PRINTER SETUP
    AX = 111Fh
    STACK: WORD function
        5E02h  set printer setup
        5E03h  get printer setup
        5E04h  set printer mode
        5E05h  get printer mode
Return: CF set on error
        AX = error code (see INT 21/AH=59h)
    STACK unchanged
Note:    called by DOS 3.1+ kernel
SeeAlso: INT 21/AX=5E02h,INT 21/AX=5E03h,INT 21/AX=5E04h,INT 21/AX=5E05h
----------2F1120-----------------------------
INT 2F CU - NETWORK REDIRECTOR - FLUSH ALL DISK BUFFERS
    AX = 1120h
    DS = DOS DS
    ???
Return: CF clear (successful)
Notes:    called by 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
----------2F1121-----------------------------
INT 2F CU - NETWORK REDIRECTOR - SEEK FROM END OF REMOTE FILE
    AX = 1121h
    CX:DX = offset (in bytes) from end
    ES:DI -> SFT
        SFT DPB field -> DPB of drive with file
    SS = DOS DS
Return: CF set on error
        AL = DOS error code (see INT 21/AH=59h)
    CF clear if successful
        DX:AX = new file position
Note:    called by DOS 3.1+ kernel
SeeAlso: AX=1228h,INT 21/AH=42h
----------2F1122-----------------------------
INT 2F CU - NETWORK REDIRECTOR - PROCESS TERMINATION HOOK
    AX = 1122h
    SS = DOS DS
    ???
Return: ???
Note:    called by DOS 3.1+ kernel
----------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 MSDOS 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
----------2F1124-----------------------------
INT 2F CU - NETWORK REDIRECTOR - PRINTER OFF???
    AX = 1124h
    ES:DI -> SFT
    SS = DOS DS
    ???
Return: CX = ???
Note:    called by DOS 3.1+ kernel if AX=1126h returns CF set
SeeAlso: AX=1126h
----------2F1125-----------------------------
INT 2F CU - NETWORK REDIRECTOR - REDIRECTED PRINTER MODE
    AX = 1125h
    STACK: WORD subfunction
        5D07h get print stream state
            Return: DL = current state
        5D08h set print stream state
            DL = new state
        5D09h finish print job
Return: CF set on error
        AX = error code (see INT 21/AH=59h)
    STACK unchanged
Note:    called by DOS 3.1+ kernel
SeeAlso: INT 21/AX=5D07h,INT 21/AX=5D08h,INT 21/AX=5D09h
----------2F1126-----------------------------
INT 2F CU - NETWORK REDIRECTOR - PRINTER ON/OFF???
    AX = 1126h
    ES:DI -> SFT for file handle 4???
    SS = DOS DS???
    ???
Return: CF set on error
Notes:    called by 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
----------2F1127-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - UNUSED
    AX = 1127h
Return: CF set
        AX = 0001h (invalid function) (see INT 21/AH=59h)
----------2F1128-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - UNUSED
    AX = 1128h
Return: CF set
        AX = 0001h (invalid function) (see INT 21/AH=59h)
----------2F1129-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - UNUSED
    AX = 1129h
Return: CF set
        AX = 0001h (invalid function) (see INT 21/AH=59h)
----------2F112A-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - ???
    AX = 112Ah
    DS = DOS DS
    ???
Return: ???
Note:    does something to each IFS driver
----------2F112B-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - GENERIC IOCTL???
    AX = 112Bh
    SS = DOS DS
    CX = function/category
    DS:DX -> parameter block
    STACK: WORD value of AX on entry to INT 21 (440Ch or 440Dh)
    ???
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
Note:    called by DOS 4.0 kernel
----------2F112C-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - ???
    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
----------2F112D-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - ???
    AX = 112Dh
    BL = subfunction (value of AL on INT 21)
        04h truncate open file to zero length
        ES:DI -> SFT for file
        Return: CF clear
        else ???
        Return: CX = ??? (00h or 02h for DOS 4.01)
    ES:DI -> SFT
    SS = DOS DS
Return: DS = DOS DS
Note:    called by DOS 4.0 kernel on INT 21/AX=5702h,INT 21/AX=5703h,
      INT 21/AX=5704h
----------2F112E-----------------------------
INT 2F CU - NETWORK REDIRECTOR (DOS 4+) - EXTENDED OPEN/CREATE FILE
    AX = 112Eh
    SS = DS = DOS DS
    ES:DI -> uninitialized SFT for file
    STACK: WORD file attribute for created/truncated file
            low byte = file attributes
            high byte = 00h normal create/open, 01h create new file
    SDA first filename pointer -> fully-qualified filename
    SDA extended file open action = action code (see INT 21/AX=6C00h)
    SDA extended file open mode = open mode for file (see INT 21/AX=6C00h)
Return: CF set on error
        AX = error code
    CF clear if successful
        CX = result code
        01h file opened
        02h file created
        03h file replaced (truncated)
        SFT initialized (except handle count, which DOS manages itself)
Note:    called by DOS 4.0 kernel
SeeAlso: AX=1115h,AX=1116h,AX=1117h,INT 21/AX=6C00h
----------2F112F-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - ???
    AX = 112Fh
    SS = DOS DS
    STACK: WORD function in low byte
        00h ???
            DS:SI -> Current Directory Structure???
            CL = drive (1=A:)
        01h ???
            DS:SI -> ???
            CL = file handle???
        02h ???
            DS:SI -> Current Directory Structure???
            DI = ???
            CX = drive (1=A:)
    ???
Return: CF set on error
        AX = DOS error code (see INT 21/AH=59h)
    CF clear if successful
Note:    called by DOS 4.0 kernel
SeeAlso: INT 21/AH=6Bh
----------2F1130-----------------------------
INT 2F CU - IFSFUNC.EXE (DOS 4.x only) - GET IFSFUNC SEGMENT
    AX = 1130h
Return: ES = CS of resident IFSFUNC
----------2F1186-----------------------------
INT 2F - LAN Manager Enhanced DOS API - DosReadAsynchNmPipe
    AX = 1186h
    ???
Return: ???
Note:    LAN Manager enhance mode adds features beyond the standard redirector
      file/printer services
SeeAlso: AX=118Fh,INT 21/AX=5F39h
----------2F118A-----------------------------
INT 2F - LAN Manager 2.0 DOS Enhanced ENCRYPT.EXE - STREAM ENCRYPTION SERVICE
    AX = 118Ah
    ???
Return: ???
SeeAlso: AX=1186h,AH=41h,AH=42h,AH=4Bh
----------2F118F-----------------------------
INT 2F - LAN Manager Enhanced DOS API - DosWriteAsynchNmPipe
    AX = 118Fh
    ???
Return: ???
SeeAlso: AX=1186h,INT 21/AX=5F3Ah
----------2F1200-----------------------------
INT 2F U - DOS 3+ internal - INSTALLATION CHECK
    AX = 1200h
Return: AL = FFh (for compatibility with other INT 2F functions)
----------2F1201-----------------------------
INT 2F U - DOS 3+ internal - CLOSE CURRENT FILE
    AX = 1201h
    SS = DOS DS (must be using a DOS internal stack)
    SDA current SFT pointer -> SFT of file to close
Return: CF set on error
    BX???
    CX new reference count of SFT
    ES:DI -> SFT for file
SeeAlso: AX=1106h,AX=1227h,INT 21/AH=3Eh
----------2F1202-----------------------------
INT 2F U - DOS 3+ internal - GET INTERRUPT ADDRESS
    AX = 1202h
    STACK: WORD vector number
Return: ES:BX -> interrupt vector
    STACK unchanged
----------2F1203-----------------------------
INT 2F U - DOS 3+ internal - GET DOS DATA SEGMENT
    AX = 1203h
Return: DS = data segment of IBMDOS.COM/MSDOS.SYS
Note:    for DOS prior to version 5.0, the data segment is the same as the code
      segment
----------2F1204-----------------------------
INT 2F U - DOS 3+ internal - NORMALIZE PATH SEPARATOR
    AX = 1204h
    STACK: WORD character to normalize
Return: AL = normalized character (forward slash turned to backslash, all
        others unchanged)
    ZF set if path separator
    STACK unchanged
----------2F1205-----------------------------
INT 2F U - DOS 3+ internal - OUTPUT CHARACTER TO STANDARD OUTPUT
    AX = 1205h
    STACK: WORD character to output
Return: STACK unchanged
Note:    can be called only from within DOS
----------2F1206-----------------------------
INT 2F U - DOS 3+ internal - INVOKE CRITICAL ERROR
    AX = 1206h
    DI = error code
    BP:SI -> device driver header
    SS = DOS DS (must be using a DOS internal stack)
    STACK: WORD value to be passed to INT 24 in AX
Return: AL = 0-3 for Abort, Retry, Ignore, Fail
    STACK unchanged
SeeAlso: INT 24
----------2F1207-----------------------------
INT 2F U - DOS 3+ internal - MAKE DISK BUFFER MOST-RECENTLY USED
    AX = 1207h
    DS:DI -> disk buffer
Return: nothing
Desc:    move the indicated buffer to the end of the disk buffer chain (least-
      recently used is first); under DOS 3.3, the buffer is then moved to
      the start of the disk buffer chain if it was marked unused
Note:    can be called only from within DOS
SeeAlso: AX=120Fh
----------2F1208-----------------------------
INT 2F U - DOS 3+ internal - DECREMENT SFT REFERENCE COUNT
    AX = 1208h
    ES:DI -> SFT
Return: AX = original value of reference count
Notes:    if the reference count was 1, it is set to FFFFh (since 0 indicates
      that the SFT is not in use).    It is the caller's responsibility to
      set the reference count to zero after cleaning up.
    used by network redirectors such as MSCDEX
SeeAlso: AX=1106h
----------2F1209-----------------------------
INT 2F U - DOS 3+ internal - FLUSH AND FREE DISK BUFFER
    AX = 1209h
    DS:DI -> disk buffer
Return: disk buffer marked unused, contents written to disk if buffer dirty
Note:    can be called only from within DOS
SeeAlso: AX=120Eh,AX=1215h
----------2F120A-----------------------------
INT 2F U - DOS 3+ internal - PERFORM CRITICAL ERROR INTERRUPT
    AX = 120Ah
    DS = SS = DOS DS (must be using a DOS internal stack)
    STACK: WORD extended error code
Return: AL = user response (0=ignore, 1=retry, 2=abort, 3=fail)
    CF clear if retry, set otherwise
    STACK unchanged
Notes:    can only be called during a DOS function call, as it uses various
      fields in the SDA to set up the registers for the INT 24
    reportedly sets current DPB's first root directory sector to 1
SeeAlso: INT 24
----------2F120B-----------------------------
INT 2F U - DOS 3+ internal - SIGNAL SHARING VIOLATION TO USER
    AX = 120Bh
    ES:DI -> system file table entry for previous open of file
    STACK: WORD extended error code (should be 20h--sharing violation)
Return: CF clear if operation should be retried
    CF set if operation should not be retried
        AX = error code (20h) (see INT 21/AH=59h)
    STACK unchanged
Notes:    can only be called during a DOS function call
    should only be called if an attempt was made to open an already-open
      file contrary to the sharing rules
    invokes INT 24 if SFT file opened via FCB or in compatibility mode with
      inheritance allowed
----------2F120C-----------------------------
INT 2F U - DOS 3+ internal - OPEN DEVICE AND SET SFT OWNER???
    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
----------2F120D-----------------------------
INT 2F U - DOS 3+ internal - GET DATE AND TIME
    AX = 120Dh
    SS = DOS DS (must be using a DOS internal stack)
Return: AX = current date in packed format (see INT 21/AX=5700h)
    DX = current time in packed format (see INT 21/AX=5700h)
SeeAlso: INT 21/AH=2Ah,INT 21/AH=2Ch
----------2F120E-----------------------------
INT 2F U - DOS 3+ internal - MARK ALL DISK BUFFERS UNREFERENCED
    AX = 120Eh
    SS = DOS DS (must be using a DOS internal stack)
Return: DS:DI -> first disk buffer
Note:    clears "referenced" flag on all disk buffers
SeeAlso: AX=1209h,AX=1210h,INT 21/AH=0Dh
----------2F120F-----------------------------
INT 2F U - DOS 3+ internal - MAKE BUFFER MOST RECENTLY USED
    AX = 120Fh
    DS:DI -> disk buffer
    SS = DOS DS (must be using a DOS internal stack)
Return: DS:DI -> next buffer in buffer list
Desc:    move the indicated buffer to the end of the disk buffer chain (least-
      recently used is first); under DOS 3.3, the buffer is then moved to
      the start of the disk buffer chain if it was marked unused
Note:    this function is the same as AX=1207h except that it returns a
      pointer to the buffer following the specified buffer in the buffer
      chain
SeeAlso: AX=1207h
----------2F1210-----------------------------
INT 2F U - DOS 3+ internal - FIND UNREFERENCED DISK BUFFER
    AX = 1210h
    DS:DI -> first disk buffer to check
Return: ZF clear if found
        DS:DI -> first unreferenced disk buffer
    ZF set if not found
SeeAlso: AX=120Eh
----------2F1211-----------------------------
INT 2F U - DOS 3+ internal - NORMALIZE ASCIZ FILENAME
    AX = 1211h
    DS:SI -> ASCIZ filename to normalize
    ES:DI -> buffer for normalized filename
Return: destination buffer filled with uppercase filename, with slashes turned
    to backslashes
SeeAlso: AX=121Eh,AX=1221h
----------2F1212-----------------------------
INT 2F U - DOS 3+ internal - GET LENGTH OF ASCIZ STRING
    AX = 1212h
    ES:DI -> ASCIZ string
Return: CX = length of string
SeeAlso: AX=1225h
----------2F1213-----------------------------
INT 2F U - DOS 3+ internal - UPPERCASE CHARACTER
    AX = 1213h
    STACK: WORD character to convert to uppercase
Return: AL = uppercase character
    STACK unchanged
----------2F1214-----------------------------
INT 2F U - DOS 3+ internal - COMPARE FAR POINTERS
    AX = 1214h
    DS:SI = first pointer
    ES:DI = second pointer
Return: ZF set if pointers are equal, ZF clear if not equal
----------2F1215-----------------------------
INT 2F U - DOS 3+ internal - FLUSH BUFFER
    AX = 1215h
    DS:DI -> disk buffer
    SS = DOS DS (must be using a DOS internal stack)
    STACK: WORD drives for which to skip buffer
        ignore buffer if drive same as high byte, or bytes differ and
        the buffer is for a drive OTHER than that given in low byte
Return: STACK unchanged
Note:    can be called only from within DOS
SeeAlso: AX=1209h
----------2F1216-----------------------------
INT 2F U - DOS 3+ internal - GET ADDRESS OF SYSTEM FILE TABLE
    AX = 1216h
    BX = system file table entry number
Return: CF clear if successful
        ES:DI -> system file table entry
    CF set if BX greater than FILES=
SeeAlso: AX=1220h
----------2F1217-----------------------------
INT 2F U - DOS 3+ internal - GET CURRENT DIRECTORY STRUCTURE FOR DRIVE
    AX = 1217h
    SS = DOS DS (must be using a DOS internal stack)
    STACK: WORD drive (0 = A:, 1 = B:, etc)
Return: CF set on error
        (drive > LASTDRIVE)
    CF clear if successful
        DS:SI -> current directory structure for specified drive
    STACK unchanged
SeeAlso: AX=1219h
----------2F1218-----------------------------
INT 2F U - DOS 3+ internal - GET CALLER'S REGISTERS
    AX = 1218h
Return: DS:SI -> saved caller's AX,BX,CX,DX,SI,DI,BP,DS,ES (on stack)
Note:    only valid while within DOS
----------2F1219-----------------------------
INT 2F U - DOS 3+ internal - SET DRIVE???
    AX = 1219h
    SS = DOS DS (must be using a DOS internal stack)
    STACK: WORD drive (0 = default, 1 = A:, etc)
Return: ???
    STACK unchanged
Notes:    calls AX=1217h
    builds a current directory structure if inside server call
      (INT 21/AX=5D00h)
SeeAlso: AX=1217h,AX=121Fh
----------2F121A-----------------------------
INT 2F U - DOS 3+ internal - GET FILE'S DRIVE
    AX = 121Ah
    DS:SI -> filename
Return: AL = drive (0 = default, 1 = A:, etc, FFh = invalid)
    DS:SI -> filename without leading X: (if present)
SeeAlso: INT 21/AH=19h,INT 21/AH=60h
----------2F121B-----------------------------
INT 2F U - DOS 3+ internal - SET YEAR/LENGTH OF FEBRUARY
    AX = 121Bh
    CL = year - 1980
Return: AL = number of days in February
Note:    requires DS to be set to the DOS code segment
SeeAlso: INT 21/AH=2Bh
----------2F121C-----------------------------
INT 2F U - DOS 3+ internal - CHECKSUM MEMORY
    AX = 121Ch
    DS:SI -> start of memory to checksum
    CX = number of bytes
    DX = initial checksum
    SS = DOS DS (must be using a DOS internal stack)
Return: AX, CX destroyed
    DX = checksum
    DS:SI -> first byte after checksummed range
Note:    used by DOS to determine day count since 1/1/80 given a date
SeeAlso: AX=121Dh
----------2F121D-----------------------------
INT 2F U - DOS 3+ internal - SUM MEMORY
    AX = 121Dh
    DS:SI -> memory to add up
    CX = 0000h
    DX = limit
Return: AL = byte which exceeded limit
    CX = number of bytes before limit exceeded
    DX = remainder after adding first CX bytes
    DS:SI -> byte beyond the one which exceeded the limit
Note:    used by DOS to determine year or month given day count since 1/1/80
SeeAlso: AX=121Ch
----------2F121E-----------------------------
INT 2F U - DOS 3+ internal - COMPARE FILENAMES
    AX = 121Eh
    DS:SI -> first ASCIZ filename
    ES:DI -> second ASCIZ filename
Return: ZF set if filenames equivalent, ZF clear if not
SeeAlso: AX=1211h,AX=1221h
----------2F121F-----------------------------
INT 2F U - DOS 3+ internal - BUILD CURRENT DIRECTORY STRUCTURE
    AX = 121Fh
    SS = DOS DS (must be using a DOS internal stack)
    STACK: WORD drive letter
Return: ES:DI -> current directory structure (will be overwritten by next call)
    STACK unchanged
----------2F1220-----------------------------
INT 2F U - DOS 3+ internal - GET JOB FILE TABLE ENTRY
    AX = 1220h
    BX = file handle
Return: CF set on error
        AL = 6 (invalid file handle)
    CF clear if successful
        ES:DI -> JFT entry for file handle in current process
Note:    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
SeeAlso: AX=1216h,AX=1229h
----------2F1221-----------------------------
INT 2F U - DOS 3+ internal - CANONICALIZE FILE NAME
    AX = 1221h
    DS:SI -> file name to be fully qualified
    ES:DI -> 128-byte buffer for resulting canonical file name
    SS = DOS DS (must be using a DOS internal stack)
Return: (see INT 21/AH=60h)
Note:    identical to INT 21/AH=60h
SeeAlso: AX=1123h,INT 21/AH=60h
----------2F1222-----------------------------
INT 2F U - DOS 3+ internal - SET EXTENDED ERROR INFO
    AX = 1222h
    SS = DOS data segment
    SS:SI -> 4-byte records
        BYTE    error code, FFh = last record
        BYTE    error class, FFh = don't change
        BYTE    suggested action, FFh = don't change
        BYTE    error locus, FFh = don't change
    SDA error code set
Return: SI destroyed
    SDA error class, error locus, and suggested action fields set
Note:    can be called only from within DOS
SeeAlso: AX=122Dh,INT 21/AH=59h
----------2F1223-----------------------------
INT 2F U - DOS 3+ internal - CHECK IF CHARACTER DEVICE
    AX = 1223h
    DS = DOS DS
    SS = DOS DS (must be using a DOS internal stack)
    SDA+218h (DOS 3.10-3.30) = eight-character blank-padded name
    SDA+22Bh (DOS 4.0-5.0) = 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
----------2F1224-----------------------------
INT 2F U - DOS 3+ internal - 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
----------2F1225-----------------------------
INT 2F U - DOS 3+ internal - GET LENGTH OF ASCIZ STRING
    AX = 1225h
    DS:SI -> ASCIZ string
Return: CX = length of string
SeeAlso: AX=1212h
----------2F1226-----------------------------
INT 2F U - DOS 3.3+ internal - OPEN FILE
    AX = 1226h
    CL = access mode
    DS:DX -> ASCIZ filename
    SS = DOS DS (must be using a DOS internal stack)
Return: CF set on error
        AL = error code (see INT 21/AH=59h)
    CF clear if successful
        AX = file handle
Notes:    can only be called from within DOS
    equivalent to INT 21/AH=3Dh
SeeAlso: AX=1227h,INT 21/AH=3Dh
----------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
SeeAlso: AX=1106h,AX=1201h,AX=1226h,INT 21/AH=3Eh
----------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
SeeAlso: INT 21/AH=42h
----------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
Note:    equivalent to INT 21/AH=3Fh, but may only be called when already inside
      a DOS function call
SeeAlso: AX=1226h,INT 21/AH=3Fh
----------2F122A-----------------------------
INT 2F U - DOS 3.3+ internal - SET FASTOPEN ENTRY POINT
    AX = 122Ah
    BX = entry point to set (0001h or 0002h)
    DS:SI -> FASTOPEN entry point
        (entry point not set if SI = FFFFh for DOS 4+)
Return: CF set if specified entry point already set
Notes:    entry point in BX is ignored under DOS 3.30
    both entry points set to same handler by DOS 4.01

DOS 3.30+ FASTOPEN is called with:
    AL = 01h  ???
        CX = ??? seems to be offset
        DI = ??? seems to be offset
        SI = offset in DOS DS of filename
    AL = 02h  ???
    AL = 03h  open file???
        SI = offset in DOS DS of filename
    AL = 04h  ???
        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

PCDOS 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 ???

MSDOS 5.0 FASTOPEN is additionally called with:
    AL = 04h ???
        AH = 03h
        ???
    AL = 05h ???
        DL = drive (00h = A:)
        ???
    AL = 06h ???
----------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
SeeAlso: INT 21/AH=44h
----------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
SeeAlso: INT 21/AH=52h
----------2F122D-----------------------------
INT 2F U - DOS 3.3+ internal - GET EXTENDED ERROR CODE
    AX = 122Dh
Return: AX = current extended error code
SeeAlso: AX=1222h,INT 21/AH=59h
----------2F122E-----------------------------
INT 2F U - DOS 4+ internal - GET OR SET ERROR TABLE ADDRESSES
    AX = 122Eh
    DL = subfunction
        00h get standard DOS error table
        Return: ES:DI -> error table
                 (DOS 4: errors 00h-12h,50h-5Bh)
                 (DOS 5: errors 00h-26h,4Fh,51h-59h)
        01h set standard DOS error table
        ES:DI -> error table
        02h get parameter error table (errors 00h-0Ah)
        Return: ES:DI -> error table
        03h set parameter error table
        ES:DI -> error table
        04h get critical/SHARE error table (errors 13h-2Bh)
        Return: ES:DI -> error table
        05h set critical/SHARE error table
        ES:DI -> error table
        06h get ??? error table
        Return: ES:DI -> error table or 0000h:0000h
        07h set ??? error table
        ES:DI -> error table
        08h get error message retriever (see below)
        Return: ES:DI -> FAR procedure to fetch error message
        09h set ??? error table
        ES:DI -> error table
Notes:    if the returned segment on a "get" is 0001h, then the offset specifies
      the offset of the error message table within COMMAND.COM, and the
      procedure returned by DL=08h should be called
    DOS 5.0 COMMAND.COM does not allow setting any of the addresses (calls
      with DL odd are ignored); they are always returned with segment 0001h
    for DOS 5.0, the standard and critical/SHARE error tables are combined
      into a single error table
SeeAlso: AX=0500h,INT 21/AH=59h

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

Call error retrieval function with:
    AX = error number
    DI = offset of error table
Return: ES:DI -> error message (counted string)
Notes:    this function needs to access COMMAND.COM if the messages were not
      loaded into memory permanently with /MSG; the caller should assume
      that the returned message will be overwritten by the next call of
      the function
    supported by DR-DOS 5.0
----------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
----------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 from previous invocation of this function
    ES:BX from 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 3.3+ 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 (many Bulgarian viruses are known to
      use it to get the original ROM entry point)
SeeAlso: INT 13/AH=01h,INT 19
----------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:    called by 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 5.0, but undocumented in prior versions
SeeAlso: AX=1401h"NLSFUNC",AX=1402h"NLSFUNC"
----------2F1400-----------------------------
INT 2F - European MSDOS 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"
----------2F1401-----------------------------
INT 2F CU - NLSFUNC.COM - CHANGE CODE PAGE
    AX = 1401h
    DS:SI -> internal code page structure (see below)
    BX = new code page
    DX = country code???
Return: AL = status
         00h successful
         else DOS error code
Note:    called by DOS v3.3+ kernel
SeeAlso: AX=1400h"NLSFUNC",AX=1402h"NLSFUNC",INT 21/AH=66h

Format of DOS 3.30 internal code page structure:
Offset    Size    Description
 00h  8 BYTEs    ???
 08h 64 BYTEs    name of country information file
 48h    WORD    system code page
 4Ah    WORD    number of supported subfunctions
 4Ch  5 BYTEs    data to return for INT 21/AX=6502h
 51h  5 BYTEs    data to return for INT 21/AX=6504h
 56h  5 BYTEs    data to return for INT 21/AX=6505h
 5Bh  5 BYTEs    data to return for INT 21/AX=6506h
 60h 41 BYTEs    data to return for INT 21/AX=6501h
----------2F1401-----------------------------
INT 2F - European MSDOS 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"
----------2F1402-----------------------------
INT 2F CU - NLSFUNC.COM - GET COUNTRY INFO
    AX = 1402h
    BP = subfunction (same as AL for INT 21/AH=65h)
    BX = code page
    DX = country code
    DS:SI -> internal code page structure (see AX=1401h)
    ES:DI -> user buffer
    CX = size of user buffer
Return: AL = status
        00h successful
        else DOS error code
Notes:    called by 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
----------2F1402-----------------------------
INT 2F - European MSDOS 4.0 POPUP - "SavePu" - SAVE POPUP SCREEN
    AX = 1402h
    ES:DI -> save buffer (0000h:0000h for default buffer in POPUP)
Return: CF clear if successful
    CF set on error
        AX = error code
        0001h process does not own screen
        0004h unknown error
        0005h invalid pointer
SeeAlso: AX=1400h"POPUP",AX=1401h"POPUP",AX=1403h"POPUP"
----------2F1403-----------------------------
INT 2F CU - NLSFUNC.COM - SET COUNTRY INFO
    AX = 1403h
    DS:SI -> internal code page structure (see AX=1401h)
    BX = code page
    DX = country code
Return: AL = status
         ???
Note:    called by DOS v3.3+ kernel on INT 21/AH=38h
SeeAlso: AX=1402h"NLSFUNC",AX=1404h,INT 21/AH=38h"SET"
----------2F1403-----------------------------
INT 2F - European MSDOS 4.0 POPUP - "RestorePu" - RESTORE SCREEN
    AX = 1403h
    ES:DI -> buffer containing saved screen
        (0000h:0000h for default buffer in POPUP)
Return: CF clear if successful
    CF set on error
        AX = error code (see AX=1402h"POPUP")
SeeAlso: AX=1400h"POPUP",AX=1401h"POPUP",AX=1402h"POPUP"
----------2F1404-----------------------------
INT 2F CU - NLSFUNC.COM - GET COUNTRY INFO
    AX = 1404h
    BX = code page
    DX = country code
    DS:SI -> internal code page structure (see AX=1401h)
    ES:DI -> user buffer
Return: AL = status
         ???
Notes:    called by 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"
----------2F14FE-----------------------------
INT 2F U - DR-DOS 5.0 NLSFUNC - ???
    AX = 14FEh
    DI = ???
    ???
Return: ???
Note:    DR-DOS 5.0 NLSFUNC returns CF set and AX=0001h if AL was not 00h, FEh,
      or FFh on entry.
SeeAlso: AX=14FFh
----------2F14FF-----------------------------
INT 2F U - DR-DOS 5.0 NLSFUNC - ???
    AX = 14FFh
    ???
Return: ???
Note:    DR-DOS 5.0 NLSFUNC returns CF set and AX=0001h if AL was not 00h, FEh,
      or FFh on entry.
SeeAlso: AX=14FEh
----------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
----------2F1500BX0000-----------------------
INT 2F - CD-ROM - INSTALLATION CHECK
    AX = 1500h
    BX = 0000h
Return: BX = number of CD-ROM drive letters used
    CX = starting drive letter (0=A:)
Notes:    this installation check DOES NOT follow the format used by other
      software
    this installation check conflicts with the DOS 4.00 GRAPHICS.COM
      installation check
SeeAlso: INT 2F/AX=D000h"Lotus"
----------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
----------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 = 15 (invalid drive)
    CF clear if successful
SeeAlso: AX=1503h
----------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 = 15 (invalid drive)
    CF clear if successful
SeeAlso: AX=1502h
----------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 = 15 (invalid drive)
    CF clear if successful
----------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)
----------2F1506-----------------------------
INT 2F - CD-ROM - TURN DEBUGGING ON
    AX = 1506h
    BX = debugging function to enable
Note:    reserved for development
SeeAlso: AX=1507h
----------2F1507-----------------------------
INT 2F - CD-ROM - TURN DEBUGGING OFF
    AX = 1507h
    BX = debugging function to disable
Note:    reserved for development
SeeAlso: AX=1506h
----------2F1508-----------------------------
INT 2F - CD-ROM - ABSOLUTE DISK READ
    AX = 1508h
    ES:BX -> buffer
    CX = drive number (0=A:)
    SI:DI = starting sector number
    DX = number of sectors to read
Return: CF set on error
        AL = error code (15=invalid drive,21=not ready)
    CF clear if successful
SeeAlso: AX=1509h
----------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
----------2F150A-----------------------------
INT 2F - CD-ROM - RESERVED
    AX = 150Ah
----------2F150B-----------------------------
INT 2F - CD-ROM v2.00+ - DRIVE CHECK
    AX = 150Bh
    CX = drive number (0=A:)
Return: BX = ADADh if MSCDEX.EXE installed
        AX = 0000h if drive not supported
        nonzero if supported
SeeAlso: AX=150Dh
----------2F150C-----------------------------
INT 2F - CD-ROM v2.00+ - GET MSCDEX.EXE VERSION
    AX = 150Ch
Return: BH = major version
    BL = minor version
Note:    MSCDEX.EXE versions prior to 2.00 return BX=0
----------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
----------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
----------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 removed ISO/High Sierra diffs
    ES:BX -> ASCIZ path name
    SI:DI -> buffer for directory entry (see below)
         minimum 255 bytes for direct copy
Return: CF set on error
        AX = error code
    CF clear if succesful
        AX = disk format (0=High Sierra,1=ISO 9660)

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

Format of directory entry (canonicalized):
Offset    Size    Description
 00h    BYTE    length of XAR in Logical Block Numbers
 01h    DWORD    Logical Block Number of file start
 05h    WORD    size of disk in logical blocks
 07h    DWORD    file length in bytes
 0Bh  7 BYTEs    date and time
 12h    BYTE    bit flags
 13h    BYTE    interleave size
 14h    BYTE    interleave skip factor
 15h    WORD    volume set sequence number
 17h    BYTE    length of file name
 18h 38 BYTEs    ASCIZ filename
 3Eh    WORD    file version number
 40h    BYTE    number of bytes of system use data
 41h 220 BYTEs    system use data
----------2F1510-----------------------------
INT 2F - CD-ROM v2.10+ - SEND DEVICE DRIVER REQUEST
    AX = 1510h
    CX = CD-ROM drive letter (0 = A, 1 = B, etc)
    ES:BX -> CD-ROM device driver request header (see AX=0802h)
----------2F1600-----------------------------
INT 2F - MS WINDOWS - WINDOWS ENHANCED MODE INSTALLATION CHECK
    AX = 1600h
Return: AL = 00h if Windows 3.x enhanced mode or Windows/386 2.x not running
    AL = 80h if Windows 3.x enhanced mode or Windows/386 2.x not running
    AL = 01h if Windows/386 2.x running
    AL = FFh if Windows/386 2.x running
    AL = anything else
        AL = Windows major version number >= 3
        AH = Windows minor version number
Note:    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
SeeAlso: AX=160Ah,AX=4680h
----------2F1602-----------------------------
INT 2F - MS WINDOWS/386 2.x - GET API ENTRY POINT
    AX = 1602h
Return: ES:DI -> Windows/386 2.x API procedure entry point
Notes:    this interface is supported in Windows 3.x only for 2.x compatibility
    to get the current virtual machine (VM) ID in Windows/386 2.x:
        AX = 0000h
        ES:DI -> return address
        JUMP to address returned from INT 2F/AX=1602h
    After JUMP, at return address:
        BX = current VM ID.
SeeAlso: AX=0C20h
----------2F1603-----------------------------
INT 2F - RM Nimbus MSDOS 3.3 - ???
    AX = 1603h
Return: AX = 5248h ('RH')
    DS:SI -> first byte after INT 2F handler in IBMBIO.COM
----------2F1605-----------------------------
INT 2F - MS WINDOWS - WINDOWS ENH MODE & 286 DOSX INIT BROADCAST
    AX = 1605h
    ES:BX = 0000h:0000h
    DS:SI = 0000h:0000h
    CX = 0000h
    DX = flags
        bit 0 = 0 if Windows enhanced-mode initialization
        bit 0 = 1 if Microsoft 286 DOS extender initialization
        bits 1-15 reserved (undefined)
    DI = version number (major in upper byte, minor in lower)
Return: CX = 0000h if okay for Windows to load
    CX <> 0 if Windows should not load
    ES:BX -> startup info structure (see below)
    DS:SI -> virtual86 mode enable/disable callback or 0000h:0000h
Notes:    the Windows enhanced mode loader and Microsoft 286 DOS extender will
      broadcast an INT 2F/AX=1605h call when initializing.    Any DOS device
      driver or TSR can watch for this broadcast and return the appropriate
      values.  If the driver or TSR returns CX <> 0, it is also its
      responsibility to display an error message.
    each handler must first chain to the prior INT 2F handler with
      registers unchanged before processing the call
    if the handler requires local data on a per-VM basis, it must store the
      returned ES:BX in the "next" field of a startup info structure and
      return a pointer to that structure in ES:BX
    a single TSR may set the V86 mode enable/disable callback; if DS:SI is
      already nonzero, the TSR must fail the initialization by setting CX
      nonzero
SeeAlso: AX=1606h,AX=1608h,AX=4B05h

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

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

Virtual mode enable/disable procedure called with:
    AX = 0000h disable V86 mode
    AX = 0001h enable V86 mode
    interrupts disabled
Return: CF set on error
    CF clear if successful
    interrupts disabled
----------2F1606-----------------------------
INT 2F - MS WINDOWS - WINDOWS ENH MODE & 286 DOSX EXIT BROADCAST
    AX = 1606h
    DX = flags
        bit 0 = 0 if Windows enhanced-mode exit
        bit 0 = 1 if Microsoft 286 DOS extender exit
        bits 1-15 reserved (undefined)
Notes:    if the init broadcast fails (AX=1605h returned CX <> 0), then this
      broadcast will be issued immediately.
    this call will be issued in real mode
SeeAlso: AX=1605h,AX=1609h
----------2F1607-----------------------------
INT 2F - MS WINDOWS - VIRTUAL DEVICE CALL OUT API
    AX = 1607h
    BX = virtual device ID (see INT 2F/AX=1684h)
    CX = (usually) callout subfunction
Return: (usually) AX,BX,CX,DX,ES contain results
Notes:    more of a convention than an API, this call specifies a standard
      mechanism for Windows enhanced-mode virtual devices (VxD's) to talk
      to DOS device drivers and TSRs
    see below for details on several virtual devices
SeeAlso: AX=0C20h,AX=1605h,AX=1607h/BX=000Ch,AX=1607h/BX=0014h
SeeAlso: AX=1607h/BX=0015h,AX=1684h
----------2F1607BX000C-----------------------
INT 2F - MS WINDOWS - "VMD" VIRTUAL 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
----------2F1607BX0014-----------------------
INT 2F - MS WINDOWS - "VNETBIOS" VIRTUAL DEVICE API
    AX = 1607h
    BX = 0014H (VxD identifier of "VNETBIOS")
Return: ES:DI -> 128-byte table specifying VNETBIOS actions for each NetBIOS
        command code (see below)
Note:    VNETBIOS (Virtual NetBIOS) calls this function to determine whether
      the NetBIOS has an extensions Windows should know about
SeeAlso: AX=1607h/BX=000Ch,AX=1607h/BX=0015h

Values for action code:
 00h    "VN_Unknown" unknown command
 04h    "VN_No_Map"  no memory mapping necessary
 08h    "VN_Map_In"  input buffer is quickly used, so no global mapping needed
 0Ch    "VN_Map_In"  output buffer is quickly used, so no global mapping needed
 10h    "VN_Map_In_Out"     buffer is quickly used, so no global mapping needed
 14h    "VN_Chain_Send"     the chain-send command
 18h    "VN_Cancel"    special case for cancel command
 1Ch    "VN_Buffer_In"    buffer is incoming
 20h    "VN_Buffer_Out" buffer is outgoing
 24h    "VN_Buffer_In_Out" buffer used for both incoming and outgoing data
----------2F1607BX0015-----------------------
INT 2F - MS WINDOWS - "DOSMGR" VIRTUAL DEVICE API
    AX = 1607h
    BX = 0015h (VxD identifier of "DOSMGR")
    CX = function
        0000h query instance processing
        Return: CX = state
                0000h not instanced
                other instanced (DOS 5.0 kernel returns 0001h)
                DX = segment of DOS drivers
                    (unchanged if call handled by DOS 5.0)
                ES:BX -> patch table (see below)
        0001h set patches in DOS
        DX = bit mask of patch requests
            bit 0 enable critical sections
            bit 1 NOP setting/checking user ID
            bit 2 turn INT 21/AH=3Fh on STDIN into polling loop
            bit 3 trap stack fault in "SYSINIT" to WIN386
            bit 4 BIOS patch to trap "Insert disk X:" to WIN386
        Return: AX = B97Ch
            BX = bit mask of patches applied
            DX = A2ABh
        0002h remove patches in DOS (ignored by DOS 5.0 kernel)
        DX = bit mask of patch requests (see function 0001h)
        0003h get size of DOS data structures
        DX = bit mask of request (only one bit can be set)
            bit 0: Current Directory Structure size
        Return: if supported request:
                AX = B97Ch
                CX = size in bytes of requested structure
                DX = A2ABh
            else:
                all registers preserved
        0004h determine instanced data structures
        Return: AX = B97Ch if supported
            DX = A2ABh if supported (DOS 5.0 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:    the DOS 5.0 kernel provides these calls; earlier versions require a
      separate driver
    DOSMGR (DOS Manager) will check whether the OEM DOS/BIOS data has
      been instanced via INT 2F/AX=1605h and will not perform its own
      instancing of the normal DOS/BIOS data if so
SeeAlso: AX=1605h,AX=1607h/BX=000Ch,AX=1607h/BX=0014h,AX=1684h

Format of patch table:
Offset    Size    Description
 00h    WORD    number of items in patch table
 02h  N WORDs    offsets of ??? to be patched
----------2F1607BX22C0-----------------------
INT 2F - Rational Systems DOS/4GW - ???
    AX = 1607h
    BX = 22C0h
    ???
Return: ???
SeeAlso: INT 15/AX=BF02h,INT 15/AX=BF04h
----------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
----------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
----------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
----------2F160B-----------------------------
INT 2F - MS Windows 3.1 - IDENTIFY TSRs
    AX = 160Bh
    ES:DI -> communication structure (see below) or 0000h:0000h
Return: ES:DI -> communication structure
Desc:    this call allows Windows-aware TSRs to make themselves known to
      Windows.
Note:    the TSR should allocate a communication structure, place the given
      ES:DI pointer in the first field, and return a pointer to the new
      structure
SeeAlso: AX=1605h,AX=160Ch,AX=4B01h,AX=4B05h

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

Format of Norton Utilities 6.0 TSR ID block:
Offset    Size    Description
 00h    WORD    length of name string
 02h  N BYTEs    name of TSR's executable
----------2F160C-----------------------------
INT 2F - MS Windows 3.1 - DETECT ROMs
    AX = 160Ch
    ???
Return: ???
Note:    used by ROM Windows
SeeAlso: AX=160Bh
----------2F1680-----------------------------
INT 2F - MS WINDOWS, DPMI, various - RELEASE CURRENT VIRTUAL MACHINE TIME-SLICE
    AX = 1680h
Return: AL = 00h if the call is supported
    AL = 80h (unchanged) if the call is not supported
Notes:    programs can use this function in idle loops to enhance performance
      under multitaskers; this call is supported by MS Windows 3.0, DOS 5+,
      DPMI 1.0+, and will be supported in OS/2 2.0 for multitasking DOS
      applications
    does not block the program; it just gives up the remainder of the time
      slice
    should not be used by Windows-specific programs
SeeAlso: INT 15/AX=1000h,INT 15/AX=5305h,INT 21/AH=89h,INT 7A/BX=000Ah
----------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
      and increment by hand.
SeeAlso: AX=1682h,INT 15/AX=101Bh,INT 21/AH=34h
----------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
----------2F1683-----------------------------
INT 2F - MS WINDOWS 3+ - GET CURRENT VIRTUAL MACHINE ID
    AX = 1683h
Return: BX = current virtual machine (VM) ID
Notes:    Windows itself currently runs in VM 1, but this can't be relied upon
    VM IDs are reused when VMs are destroyed
    an ID of 0 will never be returned
SeeAlso: AX=1684h,AX=1685h,AX=168Bh
----------2F1684-----------------------------
INT 2F - MS WINDOWS - GET DEVICE API ENTRY POINT
    AX = 1684h
    BX = virtual device (VxD) ID (see below)
    ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point, or 0:0 if the VxD does not support an API
Note:    some Windows enhanced-mode virtual devices provide services that
      applications can access.  For example, the Virtual Display Device
      (VDD) provides an API used in turn by WINOLDAP.
SeeAlso: AX=1683h

Values for VxD ID:
 01h    VMM        Virtual Machine Manager
 02h    Debug
 03h    VPICD        Virtual Prog. Interrupt Controller (PIC) Device
 04h    VDMAD        Virtual Direct Memory Access (DMA) Device
 05h    VTD        Virtual Timer Device
 06h    V86MMGR        Virtual 8086 Mode Device
 07h    PAGESWAP    Paging Device
 08h    Parity
 09h    Reboot
 0Ah    VDD        Virtual Display Device (GRABBER)
 0Bh    VSD        Virtual Sound Device
 0Ch    VMD        Virtual Mouse Device
 0Dh    VKD        Virtual Keyboard Device
 0Eh    VCD        Virtual COMM Device
 0Fh    VPD        Virtual Printer Device
 10h    VHD        Virtual Hard Disk Device (BlockDev in Windows3.1)
 11h    VMCPD
 12h    EBIOS        Reserve EBIOS page (e.g., on PS/2)
 13h    BIOSXLAT    Map ROM BIOS API between prot & V86 mode
 14h    VNETBIOS    Virtual NetBIOS Device
 15h    DOSMGR
 16h    WINLOAD
 17h    SHELL
 18h    VMPoll
 19h    VPROD
 1Ah    DOSNET        assures network integrity across VMs
 1Bh    VFD        Virtual Floppy Device
 1Ch    VDD2        Secondary display adapter
 1Dh    WINDEBUG
 1Eh    TSRLoad        TSR instance utility
 1Fh    BiosHook    BIOS interrupt hooker VxD
 20h    Int13
 21h    PageFile    Paging File device
 22h    SCSI
 23h    MCA_POS
 24h    SCSIFD        SCSI FastDisk device
 25h    VPEND        Pen device
 26h    APM        Advanced Power Management
Note:    The high bit of the VxD ID is reserved for future use. The
    next 10 bits are the OEM # which is assigned by Microsoft. The
    low 5 bits are the device number.

Call VTD.386 entry point with:
    AX = 0000h get VTD version number
        Return: AH = major version
            AL = minor version
    AX = 0100h get current clock tick time
        Return: EDX:EAX = clock tick time in 840ns units since Windows was
                started
    AX = 0101h get current system time in milliseconds
        Return: EAX = time in milliseconds that Windows has been running
    AX = 0102h get current virtual machine time
        Return: EAX = cumulative amount of time the virtual machine has
            been active, in milliseconds
Note:    should only be called directly when TOOLHELP.DLL TimerCount() cannot
      be called
----------2F1685-----------------------------
INT 2F - MS WINDOWS - SWITCH VMs AND CALLBACK
    AX = 1685h
    BX = VM ID of virtual machine to switch to
    CX = flags
        bit 0 wait until interrupts enabled
        bit 1 wait until critical section unowned
        bits 2-15 reserved (zero)
    DX:SI = priority boost (see VMM.INC)
    ES:DI -> FAR procedure to callback
Return: CF set on error
        AX = error code
        01h invalid VM ID
        02h invalid priority boost
        03h invalid flags
    CF clear if successful
        event will be or has been called
Notes:    some DOS devices, such as networks, need to call functions in a
      specific VM. This call forces the appropriate VM to be installed.
    the callback procedure must preserve all registers and return with IRET
SeeAlso: AX=1683h,INT 15/AX=1117h
----------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
----------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
        SI = number of paragraphs of DOS extender private data
        ES:DI -> DPMI mode-switch entry point
    AX nonzero if not installed
SeeAlso: AX=1686h,INT 38/AH=10h

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

Vendor names:
 "MS-DOS"    ??? and 386MAX v6.00+
 "386MAX"    386MAX v6.00+
----------2F168B-----------------------------
INT 2F - MS Windows 3.1 - SET FOCUS TO SPECIFIED VIRTUAL MACHINE
    AX = 168Bh
    ???
Return: ???
SeeAlso: AX=1683h
----------2F168C-----------------------------
INT 2F - MS Windows 3.1 - RESTART COMMAND
    AX = 168Ch
    ???
Return: ???
Note:    WIN.COM executes specified application
----------2F1700-----------------------------
INT 2F - MS WINDOWS "WINOLDAP" - IDENTIFY WinOldAp VERSION
    AX = 1700h
Return: AX = 1700h if this version of WINOLDAP doesn't support clipboard
    AX <> 1700h
        AL = WINOLDAP major version
        AH = WINOLDAP minor version
Notes:    WinOldAp (WINOLDAP.MOD) is a Microsoft Windows extension supporting
      "old" (character-mode) application access to Dynamic Data Exchange,
      menus, and the Windows clipboard.
    this installation check DOES NOT follow the format used by other
      software
----------2F1701-----------------------------
INT 2F - MS WINDOWS "WINOLDAP" - OPEN CLIPBOARD
    AX = 1701h
Return:    AX <> 0     success
    AX = 0     clipboard is already open
----------2F1702-----------------------------
INT 2F - MS WINDOWS "WINOLDAP" - EMPTY CLIPBOARD
    AX = 1702h
Return: AX <> 0     clipboard has been emptied
    AX = 0     failure
----------2F1703-----------------------------
INT 2F - MS WINDOWS "WINOLDAP" - SET CLIPBOARD DATA
    AX = 1703h
    DX = clipboard format supported by WinOldAp:
        01h text
        02h bitmap
        03h metafile picture
        04h SYLK
        05h DIF
        06h TIFF
        07h OEM text
    ES:BX -> data (see below)
    SI:CX = size of data
Return: AX <> 0 data copied into the Clipboard
    AX = 0 failure

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

Format of metafile picture:
Offset    Size    Description
 00h    WORD    mapping mode
 02h    WORD    X extent
 04h    WORD    Y extent
 06h    WORD    picture data
----------2F1704-----------------------------
INT 2F - MS WINDOWS "WINOLDAP" - GET CLIPBOARD DATA SIZE
    AX = 1704h
    DX = clipboard format supported by WinOldAp (see AX=1703h)
Return:     DX:AX = size of data in bytes, including any headers
Failure: DX:AX = 0  no data in this format in the Clipboard
----------2F1705-----------------------------
INT 2F - MS WINDOWS "WINOLDAP" - GET CLIPBOARD DATA
    AX = 1705h
    DX = clipboard format supported by WinOldAp (see AX=1703h)
    ES:BX -> buffer
Return: AX <> 0     success
    AX = 0     error, or no data in this format in Clipboard
----------2F1708-----------------------------
INT 2F - MS WINDOWS "WINOLDAP" - CloseClipboard
    AX = 1708h
Return: AX <> 0 success
    AX = 0 failure
----------2F1709-----------------------------
INT 2F - MS WINDOWS "WINOLDAP" - COMPACT CLIPBOARD
    AX = 1709h
    SI:CX = desired size in bytes
Return: DX:AX = number of bytes in largest block of free memory
Note:    WinOldAp is responsible for including the size of any headers
----------2F170A-----------------------------
INT 2F - MS WINDOWS "WINOLDAP" - GET DEVICE CAPABILITIES
    AX = 170Ah
    DX = GDI information index
        00h device driver version
        02h device classification
        04h width in mm
        06h height in mm
        08h width in pixels
        0Ah height in pixels
        0Ch bits per pixel
        0Eh number of bit planes
        10h number of brushes supported by device
        12h number of pens supported by device
        14h number of markers supported by device
        16h number of fonts supported by device
        18h number of colors
        1Ah size required for device descriptor
        1Ch curve capabilities
        1Eh line capabilities
        20h polygon capabilities
        22h text capabilities
        24h clipping capabilities
        26h bitblt capabilities
        28h X aspect
        2Ah Y aspect
        2Ch length of hypotenuse of aspect
        58h logical pixels per inch of width
        5Ah logical pixels per inch of height
Return:     AX = integer value of the desired item
        device classification
            00h vector plotter
            01h raster display
            02h raster printer
            03h raster camera
            04h character-stream, PLP
            05h Metafile, VDM
            06h display-file
        curve capabilities
            bit 0  circles
            bit 1  pie wedges
            bit 2  chord arcs
            bit 3  ellipses
            bit 4  wide lines
            bit 5  styled lines
            bit 6  wide styled lines
            bit 7  interiors
        line capabilities
            bit 1  polylines
            bit 2  markers
            bit 3  polymarkers
            bit 4  wide lines
            bit 5  styled lines
            bit 6  wide styled lines
            bit 7  interiors
        polygon capabilities
            bit 0  polygons
            bit 1  rectangles
            bit 2  trapezoids
            bit 3  scanlines
            bit 4  wide borders
            bit 5  styled borders
            bit 6  wide styled borders
            bit 7  interiors
        text capabilities
            bit 0  output precision character
            bit 1  output precision stroke
            bit 2  clippping precision stroke
            bit 3  90-degree character rotation
            bit 4  arbitrary character rotation
            bit 5  independent X and Y scaling
            bit 6  double-size
            bit 7  integer scaling
            bit 8  continuous scaling
            bit 9  bold
            bit 10 italic
            bit 11 underline
            bit 12 strikeout
            bit 13 raster fonts
            bit 14 vector fonts
            bit 15 reserved
        clipping capabilities
            00h none
            01h clipping to rectangles
        raster capabilities
            bit 0  simple bitBLT
            bit 1  device requires banding support
            bit 2  device requires scaling support
            bit 3  supports >64K bitmap
Note:  This function returns the device-capability bits for the given display
----------2F1900-----------------------------
INT 2F U - DOS 4.x only SHELLB.COM - INSTALLATION CHECK
    AX = 1900h
Return: AL = 00h  not installed
         FFh  installed
----------2F1901BL00-------------------------
INT 2F U - DOS 4.x only SHELLB.COM - SHELLC.EXE INTERFACE
    AX = 1901h
    BL = 00h if SHELLC transient
         01h if SHELLC resident
    DS:DX -> far call entry point for resident SHELLC.EXE
Return: ES:DI -> SHELLC.EXE workspace within SHELLB.COM
Note:    SHELLB.COM and SHELLC.EXE are parts of the DOS 4.x shell
----------2F1902-----------------------------
INT 2F U - DOS 4.x only SHELLB.COM - COMMAND.COM INTERFACE
    AX = 1902h
    ES:DI -> ASCIZ full filename of current batch file, with at least the
         final filename element uppercased
    DS:DX -> buffer for results
Return: AL = 00h  failed, either
          (a) final filename element quoted at ES:DI does not match
              identity of shell batch file quoted as parameter of most
              recent call of SHELLB command, or
          (b) no more Program Start Commands available.
    AL= FFh     success, then:
        memory at DS:[DX+1] onwards filled as:
        DX+1:    BYTE    count of bytes of PSC
        DX+2: N BYTEs    Program Start Command text
            BYTE    0Dh terminator
Explanation: COMMAND.COM executes the result of this call in preference to
    reading a command from a batch file. Thus the batch file does not
    advance in execution for so long as SHELLB provides PSCs from its
    workspace. The PSCs are planted in SHELLB workspace by SHELLC, the user
    menu interface. The final PSC of a sequence is finished with a
    GOTO COMMON, which causes a loop back in the batch file which called
    SHELLC so as to execute SHELLC again. The check on batch file name
    permits PSCs to CALL nested batch files while PSCs are still stacked
    up for subsequent execution.
----------2F1903-----------------------------
INT 2F U - DOS 4.x only SHELLB.COM - COMMAND.COM interface
    AX = 1903h
    ES:DI -> ASCIZ batch file name as for AX=1902h
Return: AL = FFh if quoted batch file name matches last SHELLB parameter
    AL = 00h if it does not
----------2F1904-----------------------------
INT 2F U - DOS 4.x only SHELLB.COM - SHELLB transient to TSR intrface
    AX = 1904h
Return: ES:DI -> name of current shell batch file:
        WORD    number of bytes of name following
        BYTEs    (8 max) uppercase name of shell batch file
----------2F1A00-----------------------------
INT 2F - DOS 4+ ANSI.SYS - INSTALLATION CHECK
    AX = 1A00h
Return: AL = FFh if installed
Notes:    AVATAR.SYS also responds to this call
    documented for DOS 5+, but undocumented for DOS 4.x
----------2F1A00BX4156-----------------------
INT 2F - AVATAR.SYS - INSTALLATION CHECK
    AX = 1A00h
    BX = 4156h ('AV')
    CX = 4154h ('AT')
    DX = 4152h ('AR')
Return: AL = FFh if installed
        CF clear
        BX = AVATAR protocol level supported
        CX = driver type
        0000h AVATAR.SYS
        4456h DVAVATAR.COM inside DESQview window
        DX = 0016h
Notes:    AVATAR also identifies itself as ANSI.SYS if BX, CX, or DX differ from
      the magic values
    AVATAR.SYS is a CON replacement by George Adam Stanislav which
      interprets AVATAR command codes in the same way that ANSI interprets
      ANSI command codes
----------2F1A01-----------------------------
INT 2F U - DOS 4+ ANSI.SYS internal - GET/SET DISPLAY INFORMATION
    AX = 1A01h
    CL = function
        7Fh for GET
        5Fh for SET
    DS:DX -> parm block as for INT 21,AX=440Ch,CX=037Fh/035Fh respectively
Return: CF set on error
        AX = error code (many non-standard)
    CF clear if successful
        AX destroyed
Note:    presumably this is the DOS IOCTL interface to ANSI.SYS
SeeAlso: AX=1A02h,INT 21/AX=440Ch
----------2F1A02-----------------------------
INT 2F U - DOS 4+ ANSI.SYS internal - MISCELLANEOUS REQUESTS
    AX = 1A02h
    DS:DX -> parameter block (see below)
Note:    DOS 5.0 chains to previous handler if AL > 02h on call
SeeAlso: AX=1A01h

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

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

Format of parameter block:
Offset    Size    Description
 00h    WORD    reserved, should be 0000h
 02h    DWORD    pointer to command tail to be copied into child's PSP
 06h    DWORD    pointer to first FCB to be copied into child's PSP
 0Ah    DWORD    pointer to second FCB to be copied into child's PSP
----------2F2708-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - DELETE TASK
    AX = 2708h
    DX = task index
Return: DX = FFFFh (task deleted)
Notes:    this call should only be used for abnormal task termination, after
      first checking for open files with AX=270Ch; should not be used
      with programs that allocate EMS or XMS memory
    switches to specified task first
SeeAlso: AX=2707h
----------2F2709-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - NAME TASK
    AX = 2709h
    DX = task index
    DS:SI -> 8-byte name (8 NULs = remove name)
Return: AL = task flags
        00h ID unused or task terminated
        01h ID in use, task name table entry valid
        81h ID in use, task name fixed
    BX = task ID
    ES:DI -> name in task name table (see AX=2701h)
Note:    the task retains the given name until it terminates or the name is
      removed by specifying a name of 8 NULs.
SeeAlso: AX=2701h,AX=2707h
----------2F270A-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - CONVERT TASK INDEX TO TASK ID
    AX = 270Ah
    DX = task index
Return: DX = task ID (FFFFh if index invalid)
Note:    task IDs stay constant, while indexes can change when other tasks are
      deleted
SeeAlso: AX=2701h,AX=270Bh
----------2F270B-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - CONVERT TASK ID TO TASK INDEX
    AX = 270Bh
    DX = task ID
Return: DX = task index (FFFFh if task not active)
SeeAlso: AX=270Ah
----------2F270C-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - CHECK OPEN FILES
    AX = 270Ch
    DX = task index
Return: AX = number of files currently open for specified task
SeeAlso: AX=2708h
----------2F270D-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - CHECK IF TASK RUNNING PRIMARY COMMAND INTERPRETER
    AX = 270Dh
    DX = task index
Return: DX = status
        0000h if primary command interpreter (COMMAND.COM, etc.) running
        0001h if not in root shell for task
Note:    TaskMAX will return 0001h if the specified task has spawned another
      command interpreter with AX=2707h
SeeAlso: AX=2707h,AX=270Ch
----------2F270E-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - GET/SET TEXT PASTE LEAD-IN
    AX = 270Eh
    CX = length of string (max 15 keystrokes, 0000h to get current string)
    DS:SI -> pasting lead-in string (character/scan-code pairs)
Return: ES:DI -> current lead-in string
Note:    the specified sequence of keystrokes is sent to the application before
      every line of a text-mode spreadsheet paste
SeeAlso: AX=270Fh,AX=2710h,AX=2713h
----------2F270F-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - GET/SET NUMERIC PASTE LEAD-IN
    AX = 270Fh
    CX = length of string (max 15 keystrokes, 0000h to get current string)
    DS:SI -> pasting lead-in string (character/scan-code pairs)
Return: ES:DI -> current lead-in string
Note:    the specified sequence of keystrokes is sent to the application before
      every number in a numeric-mode spreadsheet paste
SeeAlso: AX=270Eh,AX=2710h,AX=2711h,AX=2713h
----------2F2710-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - GET/SET PASTE LINE TERMINATOR STRING
    AX = 2710h
    CX = length of string (max 15 keystrokes, 0000h to get current string)
    DS:SI -> pasting lead-in string (character/scan-code pairs)
Return: ES:DI -> current lead-in string
Note:    the specified sequence of keystrokes is sent to the application after
      every line of a spreadsheet paste operation
SeeAlso: AX=270Eh,AX=270Fh,AX=2713h
----------2F2711-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - GET/SET NUMERIC PASTE DECIMAL POINT
    AX = 2711h
    DX = ASCII code for separator (FFFFh to get current)
Return: DL = current separator character
SeeAlso: AX=270Fh
----------2F2712-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - INITIATE EXPORTING TASK DATA
    AX = 2712h
    DX = task index
----------2F2713-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - INITIATE PASTE OPERATION
    AX = 2713h
    DX = task index
    CX = past mode
        0000h alphanumeric
        0001h numeric
        0002h text
SeeAlso: AX=270Eh,AX=270Fh,AX=2710h,AX=2711h
----------2F2714-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - GET SWAP SPACE INFO
    AX = 2714h
Return: CX = total KB of swap space
    DX = available KB of swap space
SeeAlso: AX=2701h
----------2F2715-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - SWITCH TO TASK MANAGER
    AX = 2715h
Return: only after calling task is again selected
SeeAlso: AX=2706h
----------2F2716-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - GET PASTE BUFFER STATUS
    AX = 2716h
Return: AX = 0000h if AX=2716h,AX=2717h,AX=2718h supported
        CX = bytes in paste buffer
        DX = current generation number (updated after every copy operation)
SeeAlso: AX=2701h,AX=2713h,AX=2714h,AX=2717h,AX=2718h
----------2F2717-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - PASTE DATA DIRECTLY TO APPLICATION BUFFER
    AX = 2717h
    CX = bytes in destination buffer
    ES:DI -> destination buffer
Return: AX = 0000h if function supported
        CX = bytes actually copied (FFFFh if buffer too small)
        DX = current generation number for paste buffer
Note:    the destination buffer may be too small if another task adds more data
      to the paste buffer after the AX=2716h call but before this call
SeeAlso: AX=2713h,AX=2716h,AX=2718h
----------2F2718-----------------------------
INT 2F - DR-DOS 6.0 TaskMAX - COPY DATA DIRECTLY INTO PASTE BUFFER
    AX = 2718h
    CX = bytes in source buffer
    DS:SI -> source buffer (plain ASCII, lines terminated with CR LF)
Return: AX = 0000h if function supported
        CX = bytes actually copied
        DX = current generation number for paste buffer
SeeAlso: AX=2712h,AX=2716h,AX=2717h
----------2F2A-------------------------------
INT 2F - Gammafax DOS Dispatcher INTERFACE
    AH = 2Ah
Note:    details not available at this time
SeeAlso: AX=8000h"FaxBIOS",AX=C000h"MTEZ",AX=CB00h,AX=CBDDh,INT 66"BitFax"
----------2F3900-----------------------------
INT 2F - Kingswood TSR INTERFACE - COMPATIBILITY MODE
    AX = 3900h
Return: AL = status
        00h not installed
        FFh one or more TSRs using this interface is installed
Note:    this function is provided to that the multiplex number will appear used
      to other programs
SeeAlso: AH=39h/BL=00h
----------2F39--BL00-------------------------
INT 2F - Kingswood TSR INTERFACE - INSTALLATION CHECK
    AH = 39h
    BL = 00h
    AL = TSR ID number (01h-FFh, currently only 01h-0Eh used) (see below)
Return: AL = status
        00h not installed
        FFh installed
        DX = segment address of resident module
Note:    All of Kingswood Software's TSRs use this interface.  Usually the
      resident module is installed by allocating a block of upper memory,
      setting its owner ID to 0008h (DOS data), and filling the MCB name
      field with the TSR's name.
SeeAlso: AX=3900h,AH=39h/BL=01h

Values for TSR ID number:
 01h TSR Windows
 02h NOBUSY
 03h CD STACK
 04h DISK WATCH
 05h PUSHBP
 06h ALIAS
 07h KEYMACRO
 08h SLOWDOWN
 09h ANSIGRAB
 0Ah TEE
 0Bh FASTMOUS
 0Ch EXTWILD
 0Dh BREAKOUT
 0Eh STOPDISK

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

Format of interrupt list entry:
Offset    Size    Description
 00h    BYTE    interrupt number (00h-FEh)
 01h    WORD    offset within segment of DWORD pointer to previous interrupt
 03h    WORD    offset within segment of begin of interrupt handler code
----------2F39--BL01-------------------------
INT 2F - Kingswood TSR INTERFACE - REMOVAL CHECK
    AH = 39h
    BL = 01h
    AL = TSR ID number (01h-FFh) (see AH=39h/BL=00h)
Return: AL = status
        00h not ready to be removed
        FFh resident module may be removed by deassigning the interrupts
        hooked by the TSR and deallocating the TSR's memory block
    AH,BX,CX,DX,ES may be destroyed
SeeAlso: AX=3900h,AH=39h/BL=00h
----------2F39-------------------------------
INT 2F - Kingswood TSR INTERFACE - APPLICATION-SPECIFIC FUNCTION CALLS
    AH = 39h
    BL = function number (02h-FFh)
    AL = TSR ID number (01h-FFh)
    CX,DX,SI,DI,DS,ES may contain parameters
Return: as appropriate for the called function
SeeAlso: AX=3900h,AH=39h/BL=00h,AX=3901h/BL=02h
----------2F3901BL02-------------------------
INT 2F - Kingswood TSR Windows - OPEN WINDOW
    AX = 3901h
    BL = 02h
Return: AX = error code (0000h if successful)
Notes:    opens the next TSR window on top of any others.     Only three
      TSR windows can be opened at any one time.  The three windows
      are all 40x11 characters, partly overlapping.
SeeAlso: AH=39h/BL=00h,AX=3901h/BL=03h,AX=3901h/BL=05h,AX=3901h/BL=06h
----------2F3901BL03-------------------------
INT 2F - Kingswood TSR Windows - HIDE WINDOWS
    AX = 3901h
    BL = 03h
Return: AX = error code (0000h if successful)
Notes:    Hide any visible TSR windows from view.
SeeAlso: AH=39h/BL=00h,AX=3901h/BL=02h,AX=3901h/BL=05h
----------2F3901BL04-------------------------
INT 2F - Kingswood TSR Windows - SHOW WINDOWS
    AX = 3901h
    BL = 04h
Return: AX = error code (0000h if successful)
Notes:    Re-display all TSR windows after a HIDE WINDOWS call.
SeeAlso: AH=39h/BL=00h,AX=3901h/BL=02h,AX=3901h/BL=03h
----------2F3901BL05-------------------------
INT 2F - Kingswood TSR Windows - CLOSE WINDOW
    AX = 3901h
    BL = 05h
Return: AX = error code (0000h if successful)
Notes:    Close the last opened TSR window.
SeeAlso: AH=39h/BL=00h,AX=3901h/BL=02h
----------2F3901BL06-------------------------
INT 2F - Kingswood TSR Windows - SET WINDOW TITLE
    AX = 3901h
    BL = 06h
    DS:SI -> title string
Return: AX = error code (0000h if successful)
SeeAlso: AH=39h/BL=00h,AX=3901h/BL=02h
----------2F3901BL07-------------------------
INT 2F - Kingswood TSR Windows - POSITION CURSOR
    AX = 3901h
    BL = 07h
    CH = Y coordinate (0-10)
    CL = X coordinate (0-39)
Return: AX = error code (0000h if successful)
Note:    the hardware cursor is always disabled when a TSR window is opened;
      this call only sets a text position
SeeAlso: AH=39h/BL=00h,AX=3901h/BL=08h,AX=3901h/BL=09h
----------2F3901BL08-------------------------
INT 2F - Kingswood TSR Windows - DISPLAY STRING
    AX = 3901h
    BL = 08h
    DS:SI -> string
Return: AX = error code (0000h if successful)
Notes:    The text is not clipped.
    This routine understands Tab, NewLine and Carriage Return
SeeAlso: AH=39h/BL=00h,AX=3901h/BL=07h
----------2F3901BL09-------------------------
INT 2F - Kingswood TSR Windows - SCROLL WINDOW
    AX = 3901h
    BL = 09h
    CL = scroll direction: 00h up, FFh down, 00h clear window
Return: AX = error code (0000h if successful)
SeeAlso: AH=39h/BL=00h,AX=3901h/BL=07h
----------2F3901BL0A-------------------------
INT 2F - Kingswood TSR Windows - SOUND BEEPER
    AX = 3901h
    BL = 0Ah
    DX = sound divisor, or 0 for silence.
         (divide 1843200 by required frequency to get value for DX)
    CL = sound length in 18.2 Hz clock ticks
Return: AX = error code (0000h if successful)
SeeAlso: AH=39h/BL=00h
----------2F3901BL0B-------------------------
INT 2F - Kingswood TSR Windows - ADD OR REMOVE USER
    AX = 3901h
    BL = 0Bh
    CL = number of users increment: +1 if adding a new user
                    -1 if removing a user
Return: AX = error code (0000h if successful)
Note:    the TSR windows resident module may only be removed when the internal
      user count is zero
SeeAlso: AH=39h/BL=00h,AX=3901h/BL=02h
----------2F4000-----------------------------
INT 2F - Windows 3.x (OS/2 2.x???) - GET VIRTUAL DEVICE DRIVER (VDD) CAPABLTIES
    AX = 4000h
Return: AL = 01h does not virtualize video access
         02h virtualizes the video when in text mode
         03h virtualizes the video when in text mode or single plane
         graphics modes
         04h virtualizes the video when in text mode, single plane
         graphics modes, and VGA multiplane modes
         FFh virtualizes the video fully
Note:    this function is used by display drivers to find out what capabilities
      exist for the VDD driver and also trigger then VDD driver to call
      functions 4005h and 4006h.  This function also gives the Video Driver
      hardware access to the video registers.
----------2F4001-----------------------------
INT 2F C - OS/2 compatibility box - SWITCHING DOS TO BACKGROUND
    AX = 4001h
Note:    called by OS/2 when the DOS box is about to be placed in the background
      and the video driver should save any necessary state
SeeAlso: AX=4002h,AX=4005h
----------2F4002-----------------------------
INT 2F C - OS/2 compatibility box - SWITCHING DOS TO FOREGROUND
    AX = 4002h
Note:    called by OS/2 when the DOS box is about to be placed in the foreground
      and the video driver should restore the previously-saved state
SeeAlso: AX=4001h,AX=4006h
----------2F4003-----------------------------
INT 2F - Windows 3.x - ENTERING VIDEO DRIVER CRITICAL SECTION
    AX = 4003h
Note:    This critical section must be exited within 1 second.
SeeAlso: AX=4004h
----------2F4004-----------------------------
INT 2F - Windows 3.x - EXITING VIDEO DRIVER CRITICAL SECTION
    AX = 4004h
SeeAlso: AX=4003h
----------2F4005-----------------------------
INT 2F C - Windows 3.x - SWITCHING DOS TO BACKGROUND
    AX = 4005h
Note:    called by Windows when the DOS box is about to be placed in the
      background and the video driver should save any necessary state
      information
SeeAlso: AX=4001h,AX=4006h
----------2F4006-----------------------------
INT 2F C - Windows 3.x - SWITCHING DOS TO FOREGROUND
    AX = 4006h
Note:    called by Windows when the DOS box is about to be placed in the
      foreground and the video driver should restore any necessary state
      information
SeeAlso: AX=4002h,AX=4005h
----------2F4007-----------------------------
INT 2F - Windows 3.x - ENABLE VDD TRAPPING OF VIDEO REGISTERS
    AX = 4007h
----------2F4040-----------------------------
INT 2F - PharLap 286|DOS-Extender Lite v2.5 - ???
    AX = 4040h
Return: BX:CX -> ???
----------2F41-------------------------------
INT 2F - LAN Manager 2.0 DOS Enhanced NETPOPUP.EXE - NETWORK POP-UP SERVICE
    AH = 41h
    ???
Return: ???
Note:    LAN Manager enhanced mode adds features beyond the standard redirector
      file/printer services
SeeAlso: AX=118Ah,AH=42h,AH=4Bh
----------2F42-------------------------------
INT 2F - LAN Manager 2.0 DOS Enhanced MSRV.EXE - MESSENGER SERVICE
    AH = 42h
    ???
Return: ???
Note:    LAN Manager enhanced mode adds features beyond the standard redirector
      file/printer services
SeeAlso: AX=118Ah,AH=41h,AH=4Bh
----------2F4300-----------------------------
INT 2F - EXTENDED MEMORY SPECIFICATION (XMS) - INSTALLATION CHECK
    AX = 4300h
Return: AL = 80h XMS driver installed
    AL <> 80h no driver
Notes:    XMS gives access to extended memory and noncontiguous/nonEMS memory
      above 640K
    this installation check DOES NOT follow the format used by other
      software
SeeAlso: AX=4310h
---------------------------------------------
INT 2F U - HIMEM.SYS v2.77+ - GET A20 HANDLER NUMBER
    AX = 4308h
Return: AL = 43h if supported
        BL = A20 handler number (value of /MACHINE:nn switch)
        BH = AT A20 switch time (00h medium, 01h fast, 02h slow)
SeeAlso: AX=4330h
----------2F4310-----------------------------
INT 2F - EXTENDED MEMORY SPECIFICATION (XMS) - GET DRIVER ADDRESS
    AX = 4310h
Return: ES:BX -> driver entry point
Note:    HIMEM.SYS v2.77 chains to previous handler if AH is not 00h or 10h
SeeAlso: AX=4300h

Perform a FAR call to the driver entry point with AH set to the function code
    AH    function
    00h  Get XMS version number
         Return: AX = XMS version (in BCD, AH=major, AL=minor)
             BX = internal revision number
             DX = 0001h if HMA (1M to 1M + 64K) exists
              0000h if HMA does not exist
    01h  Request High Memory Area (1M to 1M + 64K)
         DX = memory in bytes (for TSR or device drivers)
          FFFFh if application program
         Return: AX = 0001h success
            = 0000h failure
               BL = error code (80h,81h,90h,91h,92h) (see below)
    02h  Release High Memory Area
         Return: AX = 0001h success
            = 0000h failure
               BL = error code (80h,81h,90h,93h) (see below)
    03h  Global enable A20, for using the HMA
         Return: AX = 0001h success
            = 0000h failure
               BL = error code (80h,81h,82h) (see below)
    04h  Global disable A20
         Return: AX = 0001h success
            = 0000h failure
               BL = error code (80h,81h,82h,94h) (see below)
    05h  Local enable A20, for direct access to extended memory
         Return: AX = 0001h success
            = 0000h failure
               BL = error code (80h,81h,82h) (see below)
    06h  Local disable A20
         Return: AX = 0001h success
            = 0000h failure
               BL = error code (80h,81h,82h,94h) (see below)
    07h  Query A20 state
         Return: AX = 0001h enabled
            = 0000h disabled
             BL = error code (00h,80h,81h) (see below)
    08h  Query free extended memory, not counting HMA
         BL = 00h (some implementations leave BL unchanged on success)
         Return: AX = size of largest extended memory block in K
             DX = total extended memory in K
             BL = error code (00h,80h,81h,A0h) (see below)
    09h  Allocate extended memory block
         DX = Kbytes needed
         Return: AX = 0001h success
               DX = handle for memory block
            = 0000h failure
               BL = error code (80h,81h,A0h) (see below)
    0Ah  Free extended memory block
         DX = handle of block to free
         Return: AX = 0001h success
            = 0000h failure
               BL = error code (80h,81h,A2h,ABh) (see below)
    0Bh  Move extended memory block
         DS:SI -> EMM structure (see below)
         Note: if either handle is 0000h, the corresponding offset is
           considered to be an absolute segment:offset address in
           directly addressable memory
         Return: AX = 0001h success
            = 0000h failure
               BL = error code (80h-82h,A3h-A9h) (see below)
    0Ch  Lock extended memory block
         DX = handle of block to lock
         Return: AX = 0001h success
               DX:BX = 32-bit linear address of locked block
            = 0000h failure
               BL = error code (80h,81h,A2h,ACh,ADh) (see below)
    0Dh  Unlock extended memory block
         DX = handle of block to unlock
         Return: AX = 0001h success
            = 0000h failure
               BL = error code (80h,81h,A2h,AAh) (see below)
    0Eh  Get handle information
         DX = handle for which to get info
         Return: AX = 0001h success
               BH = block's lock count
               BL = number of free handles left
               DX = block size in K
            = 0000h failure
               BL = error code (80h,81h,A2h) (see below)
    0Fh  Reallocate extended memory block
         DX = handle of block
         BX = new size of block in K
         Return: AX = 0001h success
            = 0000h failure
               BL = error code (80h,81h,A0h-A2h,ABh) (see below)
    10h  Request upper memory block (nonEMS memory above 640K)
         DX = size of block in paragraphs
         Return: AX = 0001h success
               BX = segment address of UMB
               DX = actual size of block
            = 0000h failure
               BL = error code (80h,B0h,B1h) (see below)
               DX = largest available block
    11h  Release upper memory block
         DX = segment address of UMB to release
         Return: AX = 0001h success
            = 0000h failure
               BL = error code (80h,B2h) (see below)
    12h  (XMS v3.0) Reallocate upper memory block
         DX = segment address of UMB to resize
         BX = new size of block in paragraphs
         Return: AX = 0001h success
            = 0000h failure
               BL = error code (80h,B0h,B2h) (see below)
    34h  (QEMM 5.11 only, undocumented) ???
    44h  (QEMM 5.11 only, undocumented) ???
    88h  (XMS v3.0) Query free extended memory
         Return: EAX = largest block of extended memory, in K
             BL = status
             00h success
             80h not implemented (i.e. on a 286 system)
             81h VDISK detected
             A0h all extended memory allocated
             ECX = physical address of highest byte of memory
                (valid even on error codes 81h and A0h)
             EDX = total Kbytes of extended memory (0 if status A0h)
    89h  (XMS v3.0) Allocate any extended memory
         EDX = Kbytes needed
         Return: AX = 0001h success
                DX = handle for allocated block (free with AH=0Ah)
            = 0000h failure
                BL = status (80h,81h,A0h,A1h,A2h) (see below)
    8Eh  (XMS v3.0) Get extended EMB handle information
         DX = handle
         Return: AX = 0001h success
                BH = block's lock count
                CX = number of free handles left
                EDX = block size in K
            = 0000h failure
                BL = status (80h,81h,A2h) (see below)
    8Fh  (XMS v3.0) Reallocate any extended memory block
         DX = unlocked handle
         EBX = new size in K
         Return: AX = 0001h success
            = 0000h failure
                BL = status (80h,81h,A0h-A2h,ABh) (see below)
Notes:    HIMEM.SYS requires at least 256 bytes free stack space
    the XMS driver need not implement functions 10h through 12h to be
      considered compliant with the standard
BUG:    HIMEM v3.03-3.07 crash on an 80286 machine if any of the 8Xh functions
      are called

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

Error codes returned in BL:
    00h successful
    80h function not implemented
    81h Vdisk was detected
    82h an A20 error occurred
    8Eh a general driver error
    8Fh unrecoverable driver error
    90h HMA does not exist
    91h HMA is already in use
    92h DX is less than the /HMAMIN= parameter
    93h HMA is not allocated
    94h A20 line still enabled
    A0h all extended memory is allocated
    A1h all available extended memory handles are allocated
    A2h invalid handle
    A3h source handle is invalid
    A4h source offset is invalid
    A5h destination handle is invalid
    A6h destination offset is invalid
    A7h length is invalid
    A8h move has an invalid overlap
    A9h parity error occurred
    AAh block is not locked
    ABh block is locked
    ACh block lock count overflowed
    ADh lock failed
    B0h only a smaller UMB is available
    B1h no UMB's are available
    B2h UMB segment number is invalid
---------------------------------------------
INT 2F UC - HIMEM.SYS v2.77+ - GET EXTERNAL A20 HANDLER ADDRESS
    AX = 4330h
Return: AL = 80h if external A20 handler provided
        ES:BX -> external A20 handler
        CL = ???
Note:    HIMEM.SYS calls this function to allow an external program to provide
      an A20 handler (i.e. to support a machine not supported by HIMEM
      itself)

External A20 handler called with:
    AX = function
        0000h disable A20
        0001h enable A20
    Return: AX = status
            0000h failure
            0001h successful
SeeAlso: AX=4308h,AX=4310h
----------2F44-------------------------------
INT 2F U - ???
    AH = 44h
    AL = function (at least 0Bh, 15h, 17h)
    ???
Return: ???
Note:    called by Codeview for Windows
SeeAlso: AH=86h
----------2F4500-----------------------------
INT 2F U - Microsoft Profiler (PROF.COM/VPROD.386) - INSTALLATION CHECK
    AX = 4500h
Return: AL = 01h if PROF.COM installed
    AL = 02h if VPROD.386 installed
SeeAlso: AX=4501h,AX=4502h
----------2F4501-----------------------------
INT 2F U - Microsoft Profiler (PROF.COM/VPROD.386) - SETUP PROFILER
    AX = 4501h
    BX = CSIPS buffer size in KB (first parameter for ProfSetup)
    CX = output limit in KB (second parameter for ProfSetup)
Note:    this call is not supported by PROF.COM
SeeAlso: AX=4502h,AX=4503h
----------2F4502-----------------------------
INT 2F U - Microsoft Profiler (PROF.COM/VPROD.386) - SET SAMPLING RATE
    AX = 4502h
    BL = sampling rate for PROF.COM (0 < BL <= 13)
        (01h = 8192/s, 04h = 1024/s, 08h = 32/s, 0Dh = 1/s)
    CX = sampling rate for VPROD.386
Note:    for PROF.COM, this programs the CMOS clock by setting BL+2 as the
      low four bits of CMOS register 0Ah.  The interruption rate is
      1 SHL (15 - BL) per second.
SeeAlso: AX=4501h,AX=4503h
----------2F4503-----------------------------
INT 2F U - Microsoft Profiler (PROF.COM/VPROD.386) - START PROFILING
    AX = 4503h
Notes:    Profiling is also turned on by the key combinations
      LeftShift + RightShift + Alt
      LeftShift + RightShift + Ctrl
    for PROF.COM, this call programs the CMOS clock by reading register
      0Ch, and setting bit 6 of register 0Bh.  It then makes sure that IRQ8
      is unmasked
SeeAlso: AX=4504h
----------2F4504-----------------------------
INT 2F U - Microsoft Profiler (PROF.COM/VPROD.386) - STOP PROFILING
    AX = 4504h
Notes:    profiling is also turned off by the key combination
      LeftShift + RightShift
    for PROF.COM, this programs the CMOS clock by reading register 0Ch
      and clearing bit 6 of register 0Bh.  It then masks IRQ8.
SeeAlso: AX=4503h,AX=4505h,AX=4506h,AX=4507h
----------2F4505-----------------------------
INT 2F U - Microsoft Profiler (PROF.COM/VPROD.386) - CLEAR PROFILING DATA
    AX = 4505h
SeeAlso: AX=4503h,AX=4504h,AX=4506h
----------2F4506-----------------------------
INT 2F U - Microsoft Profiler (PROF.COM/VPROD.386) - "ProfFlush"
    AX = 4506h
SeeAlso: AX=4505h,AX=4507h
----------2F4507-----------------------------
INT 2F U - Microsoft Profiler (PROF.COM/VPROD.386) - "ProfFinish"
    AX = 4507h
Note:    this call is essentially a "ProfStop" (AX=4504h) followed by
      "ProfFlush" (AX=4506h)
SeeAlso: AX=4504h,AX=4505h,AX=4506h
----------2F4508-----------------------------
INT 2F U - Microsoft Profiler (PROF.COM/VPROD.386) - ALTERNATE SEGDEBUG IFACE
    AX = 4508h
    BX = ordinal (or 0000h)
    CX = segment
    DX = instance (or 0000h)
    SI = type (or 0000h)
    ES:DI -> ASCIZ module name
Notes:    this call is an alternate entry to the profiler's SEGDEBUG
      interface, but only to function 0, for notifying the profiler of
      each new segment loaded.  The SHOWHITS utility then examines the
      profiler's output files (CSIPS.DAT and SEGENTRY.DAT) in conjunction
      with symbol files to provide information in a useful form.
    this call does not have a corresponding Windows function
SeeAlso: AX=4500h
----------2F4601-----------------------------
INT 2F U - DOS 5.0 kernel - ???
    AX = 4601h
Return: ???
Note:    copies the MCB following the caller's PSP memory block into DOS data
      segment
SeeAlso: AX=4602h
----------2F4602-----------------------------
INT 2F U - DOS 5.0 kernel - ???
    AX = 4602h
Return: ???
Note:    copies previously copied MCB from DOS data segment into MCB following
      caller's PSP memory block
SeeAlso: AX=4601h
----------2F46-------------------------------
INT 2F U - ???
    AH = 46h
    AL = subfunction (03h,04h)
Return: ???
Note:    these two subfunctions are called by MS Windows 3.0
----------2F4653CX0002-----------------------
INT 2F - F-PROT v1.x only - F-LOCK.EXE
    AX = 4653h
    CX = 0002h
    BX = subfunction
        0000h  installation check
        Return: AX = FFFFh
        0001h  uninstall
        Return: AX,BX,ES destroyed
        0002h  disable (v1.08 and below only)
        0003h  enable (v1.08 and below only)
Note:    F-LOCK is part of the F-PROT virus/trojan protection package by Fridrik
      Skulason
SeeAlso: AX=4653h/CX=0003h,AX=CA00h,INT 21/AX=4BEEh
----------2F4653CX0003-----------------------
INT 2F - F-PROT v1.x only - F-XCHK.EXE
    AX = 4653h
    CX = 0003h
    BX = subfunction
        0000h  installation check
        Return: AX = FFFFh
        0001h  uninstall
        Return: AX,BX,ES destroyed
Note:    F-XCHK is part of the F-PROT virus/trojan protection package by Fridrik
      Skulason
SeeAlso: AX=4653h/CX=0002h,AX=4653h/CX=0004h,AX=CA00h
----------2F4653CX0004-----------------------
INT 2F - F-PROT v1.x only - F-POPUP.EXE
    AX = 4653h
    CX = 0004h
    BX = subfunction
        0000h  installation check
        Return: AX = FFFFh
        0001h  uninstall
        Return: AX,BX,ES destroyed
        0002h  disable (v1.08 and below only)
           display message (v1.14+)
            other registers: ???
        0003h  enable (v1.08 and below only)
           display message (v1.14+)
            other registers: ???
            Return: AX = key pressed by user
Note:    F-POPUP is part of the F-PROT virus/trojan protection package by
      Fridrik Skulason
SeeAlso: AX=4653h/CX=0003h,AX=4653h/CX=0005h,AX=CA00h
----------2F4653CX0005-----------------------
INT 2F - F-PROT v1.x only - F-DLOCK.EXE
    AX = 4653h
    CX = 0005h
    BX = subfunction
        0000h installation check
        Return: AX = FFFFh
        0001h uninstall
        Return: AX,BX,ES destroyed
Note:    F-DLOCK is part of the F-PROT virus/trojan protection package by
      Fridrik Skulason
SeeAlso: AX=4653h/CX=0004h,AX=CA00h
----------2F4680-----------------------------
INT 2F U - MS Windows v3.0 - INSTALLATION CHECK
    AX = 4680h
Return: AX = 0000h MS Windows 3.0 running in real (/R) or standard (/S) mode,
           or DOS 5 DOSSHELL active
       nonzero  no Windows, Windows prior to 3.0, or Windows3 in enhanced
            mode
Note:    Windows 3.1 finally provides an installation check which works in all
      modes (see AX=160Ah)
SeeAlso: AX=1600h,AX=160Ah
----------2F4800-----------------------------
INT 2F - DOS v5.0 DOSKEY - INSTALLATION CHECK
    AX = 4800h
Return: AL = nonzero if installed
SeeAlso: AX=4810h
----------2F4810-----------------------------
INT 2F - DOS v5.0 DOSKEY - READ INPUT LINE FROM CONSOLE
    AX = 4810h
    DS:DX -> line buffer (see INT 21/AH=0Ah)
Return: AX = 0000h if successful
Notes:    the first byte (length) of the buffer MUST be 80h, or DOSKEY chains to
      the previous handler
    if the user's input is a macro name, no text is placed in the buffer
      even though AX=0000h on return; the program must immediately issue
      this call again to retrieve the expansion of the macro.  Similarly,
      if the user enters a special parameter such as $*, this call must
      be repeated to retrieve the expansion; on the second call, DOSKEY
      overwrites the macro name on the screen with its expansion.
SeeAlso: AX=4800h,INT 21/AH=0Ah
----------2F4A00CX0000-----------------------
INT 2F CU - DOS v5.0 - SINGLE-FLOPPY LOGICAL DRIVE CHANGE NOTIFICATION
    AX = 4A00h
    CX = 0000h
    DH = new drive number
    DL = current drive number
Return: CX = FFFFh to skip "Insert diskette for drive X:" message
Note:    called by MSDOS 5.00 IO.SYS just before displaying the message
      "Insert diskette for drive X:" on single-floppy systems
----------2F4A01-----------------------------
INT 2F - DOS 5.0 - QUERY FREE HMA SPACE
    AX = 4A01h
Return: BX = number of bytes available in HMA (0000h if DOS not using HMA)
    ES:DI -> start of available HMA area (FFFFh:FFFFh if not using HMA)
Note:    called by Windows 3.1 DOSX.EXE
SeeAlso: AX=4310h,AX=4A02h
----------2F4A02-----------------------------
INT 2F - DOS 5.0 - ALLOCATE HMA SPACE
    AX = 4A02h
    BX = number of bytes
Return: ES:DI -> start of allocated HMA block or FFFFh:FFFFh
    BX destroyed
Notes:    this call is not valid unless DOS is loaded in the HMA (DOS=HIGH)
    called by Windows 3.1 DOSX.EXE
SeeAlso: AX=4A01h
----------2F4A05-----------------------------
INT 2F U - DOS 5.0 DOSSHELL - TASK SWITCHING API???
    AX = 4A05h
    SI = function
        0000h reset???
        0001h ???
        0002h ???
        0003h ???
        0004h ???
        BL = ???
        0005h ???
        0006h get ???
        Return: ES:DI -> ???
        0007h get ???
        Return: AX = ???
        0008h get ???
        Return: DX:AX -> ???
        0009h get ???
        Return: ES = ???
        000Ah ???
        BL = ???
        ES:DI -> ???
        000Bh get ???
        Return: AX = ???
        000Ch ???
        BL = ???
        Return: DX:AX -> ???
Notes:    DOSSHELL chains to the previous handler if SI is not one of the values
      listed above
    the DOSSWAP.EXE module calls functions 03h,04h,05h,07h,08h,09h,0Ch
    the Windows 3.1 DSWAP.EXE and WSWAP.EXE task switchers use these calls
SeeAlso: AX=4B01h
----------2F4A06-----------------------------
INT 2F CU - ??? - GET MEMORY SIZE
    AX = 4A06h
    DX = segment following last byte of conventional memory
Return: DX = segment following last byte of memory available for use by DOS
Note:    called by MSDOS 5.00 IO.SYS startup code if the signature "RPL" is
      present three bytes beyond the INT 2F handler; this call overrides
      the value returned by INT 12
SeeAlso: INT 12
----------2F4A10-----------------------------
INT 2F - SMARTDRV v4.00+ - API
    AX = 4A10h
    BX = command
        0000h installation check and hit ratios
        Return: AX = BABEh if installed
                DX:BX = cache hits
                DI:SI = cache misses
                CX = ???
                BP = version (4.00 = 0400h)
        0001h reset cache
        0002h flush buffers
        0003h status
        BP = drive # (0=A, 1=B, etc.)
        DL = subfunction
            00h only get information
            01h turn on read cache
            02h turn off read cache
            03h turn on write cache
            04h turn off write cache
        Return: AX = BABEh if OK
            DL = status
                bit 7  not cached
                bit 6  write-through
                bit 5  ???
                bits 0-4 drive # (0=A, 1=B...)
            DL = FFh if drive does not exist
        Note:    If the read cache is off, reads will not be cached,
              but writes will continue to be cached if the write-
              cache is enabled.
        0004h cache size
        Return: AX = ???
            BX = largest number of elements
            CX = size of elements in bytes
            DX = number of elements under Windows
        0005h double-buffer status
        BP = drive # (0=A, 1=B...)
        Return: AX = BABEh if double-buffered
        0007h ???
        Return: DI = random number???
        000Ah get table pointer???
        Return: ES:BX -> table of about 10 bytes or 5 words. Seems to
                be words pointing to memory addresses
                containing info??? (see below)
        1234h signal serious error
        pops up a message box saying that a serious error occurred and
          to hit R to retry.
!!!
Note:    at least partially supported by PC-Cache v8.0 (details not yet known)
SeeAlso: INT 21/AX=4402h"SMARTDRV",INT 21/AX=4403h"SMARTDRV"

Format of data table:
Offset    Size    Description
 00h  8 BYTEs    ???
 08h    WORD    offset of WORD containing number of elements in cache
----------2F4B-------------------------------
INT 2F - LAN Manager 2.0 DOS Enh NETWKSTA.EXE - NETWORK WORKSTATION REDIRECTOR
    AH = 4Bh
    ???
Return: ???
Note:    LAN Manager enhanced mode adds features beyond the standard redirector
      file/printer services
SeeAlso: AX=118Ah,AH=41h,AH=42h
----------2F4B01-----------------------------
INT 2F C - DOS v5.0 TASK SWITCHER - BUILD CALLOUT CHAIN
    AX = 4B01h
    CX:DX -> task switcher entry point (see AX=4B02h)
    ES:BX = 0000h:0000h
Return: ES:BX -> callback info structure (see below) or 0000h:0000h
Notes:    called by the task switcher
    this function is hooked by clients which require notification of task
      switcher activities; the call must first be passed on to the prior
      handler with registers unchanged using a simulated interrupt.     On
      return, the client must build a callback info structure and store
      the returned ES:BX in the "next" field, then return the address of
      its own callback info structure.
    a client program must add itself to the notification chain if it
      provides services to other programs; before terminating, it must
      remove itself from the chain by calling the task switcher's entry
      point with AX=0005h (see AX=4B02h)
    the task switcher entry point should not be saved, as it is subject to
      change and will be provided on any notification call
    the Windows 3.1 Standard Mode supports this API
SeeAlso: AX=160Bh,AX=4B02h

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

Notification function is called with:
    AX = function
        0000h switcher initialization
        Return: AX = 0000h if OK to load
               = nonzero to abort task switcher
        0001h query suspend
        BX = session ID
        Return: AX = 0000h if OK to switch session
               = 0001h if not
        0002h suspend session
        BX = session ID
        interrupts disabled
        Return: AX = 0000h if OK to switch session
               = 0001h if not
        0003h activate session
        BX = session ID
        CX = session status flags
            bit 0: set if first activation of session
            bits 1-15: reserved (0)
        interrupts disabled
        Return: AX = 0000h
        0004h session active
        BX = session ID
        CX = session status flags
            bit 0: set if first activation of session
            bits 1-15: reserved (0)
        Return: AX = 0000h
        0005h create session
        BX = session ID
        Return: AX = 0000h if OK to create session
               = 0001h if not
        0006h destroy session
        BX = session ID
        Return: AX = 0000h
        0007h switcher termination
        BX = flags
            bit 0: set if calling switcher is only switcher loaded
            bits 1-15: reserved (0)
        Return: AX = 0000h
    ES:DI -> task switcher entry point (see AX=4B02h)
Notes:    function 0000h is generally called by the program which controls or
      invokes the task switcher, rather than by the task switcher itself;
      the entry point supplied to this function is not necessarily the
      entry point to the task switcher itself, and may be 0000h:0000h.  If
      any client indicates that loading is not possible, all clients will
      be called with function 0007h; thus it is possible for a client to
      receive a termination notice without a corresponding initialization
      notice.
    except for functions 0002h and 0003h, the notification handler is
      called with interrupts enabled and may make any INT 21h function
      call; interrupts must not be enabled in functions 0002h and 0003h
    function 0007h may be called with ES:DI = 0000h:0000h if the entry
      point is no longer valid
----------2F4B02BX0000-----------------------
INT 2F - DOS v5.0 TASK SWITCHER - INSTALLATION CHECK
    AX = 4B02h
    BX = 0000h
    ES:DI = 0000h:0000h
Return: ES:DI = 0000h:0000h if task switcher not loaded
    ES:DI -> task switcher entry point (see below) if loaded
        AX = 0000h
Notes:    the returned entry point is that for the most-recently loaded task
      switcher; the entry points for prior task switchers may be determined
      with the "get version" call (see below)
    this function is supported by PC Tools v8+ CPTASK
SeeAlso: AX=4A05h,AX=4B03h

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

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

Format of API info structure:
Offset    Size    Description
 00h    WORD    size of structure in bytes (000Ah)
 02h    WORD    API identifier
        0001h NetBIOS
        0002h 802.2
        0003h TCP/IP
        0004h LAN Manager named pipes
        0005h Novell NetWare IPX
 04h    WORD    major version \ of highest version of API for which the support
 06h    WORD    minor version / level specified in the next field is provided
 08h    WORD    support level
        0001h minimal support
        0002h API-level support
        0003h switcher compatibility
        0004h seamless compatibility
----------2F4B03-----------------------------
INT 2F - DOS v5.0 TASK SWITCHER - ALLOCATE SWITCHER ID
    AX = 4B03h
    ES:DI -> task switcher entry point (see AX=4B02h)
Return: AX = 0000h
    BX = switcher ID (0001h-000Fh), or 0000h if no more available
Notes:    if a task switcher has determined that it is the first to be loaded, it
      must allocate an identifier for itself and provide this function to
      all subsequent task switchers; if it is not the first to be loaded,
      it must call this function to allocate an ID.     The switcher ID is
      used as the high four bits of all session identifiers to ensure
      unique session IDs.
    if no more switcher IDs are available, the new task switcher making the
      call must terminate or disable itself
    the task switcher providing the identifiers may call the new task
      switcher's entry point as needed
    this call is available from within DOSSHELL even if the task switcher
      is not installed
    this function is supported by PC Tools v8+ CPTASK, but appears to
      always return an ID of 0000h
SeeAlso: AX=4B02h,AX=4B04h
----------2F4B04-----------------------------
INT 2F - DOS v5.0 TASK SWITCHER - FREE SWITCHER ID
    AX = 4B04h
    BX = switcher ID
    ES:DI -> task switcher entry point (see AX=4B02h)
Return: AX = 0000h
    BX = status
        0000h successful
        other error (invalid ID or ID not allocated)
Notes:    called by a task switcher when it exits, unless it was the first loaded
      and is providing the support for AX=4B03h and AX=4B04h
    the task switcher providing the identifiers may call the terminating
      task switcher's entry point as needed
    this call is available from within DOSSHELL even if the task switcher
      is not installed
    this call is supported by PC Tools v8+ CPTASK, but appears to return
      sucessfully no matter which ID is given
SeeAlso: AX=4B02h,AX=4B03h
----------2F4B05-----------------------------
INT 2F - DOS v5.0 DOSSHELL TASK SWITCHER - IDENTIFY INSTANCE DATA
    AX = 4B05h
    ES:BX = 0000h:0000h
    CX:DX -> task switcher entry point (see AX=4B02h)
Return: ES:BX -> startup info structure (see below) or 0000h:0000h
Notes:    called by task switcher
    clients with instance data should hook this call, pass it through to
      the previous handler with unchanged registers using a simulated
      interrupt.  On return, the client should create a startup info
      structure (see below), store the returned ES:BX in the "next"
      field, and return the address of the created structure in ES:BX
    all MSDOS function calls are available from within this call
SeeAlso: AX=1605h,AX=160Bh,AX=4B02h

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

Format of one instance data record in array:
Offset    Size    Description
 00h    DWORD    address of instance data (end of array if 0000h:0000h)
 04h    WORD    size of instance data
----------2F4E53-----------------------------
INT 2F U - SilverNET - API
    AX = 4E53h ("SN")
    BH = major function class??? (04h and 02h are common)
    BL = subclass???
    CX = function number???
    ???
Return: AX = return value or status
    ???
Program: SilverNET is an SMB-compatible peer-to-peer NOS for DOS or
      Windows systems, by Net-Source of Santa Clara, CA.
SeeAlso: AX=B800h,AX=B809h
----------2F53-------------------------------
INT 2F U - ???
    AH = 53h
    AL = subfunction (0Bh, maybe others???)
Return: ???
Note:    called by MS Windows 3.1 POWER.DRV; hooked by MS Mouse driver v8.20+
      and PC-Cache v8.0
SeeAlso: AH=54h,INT 33/AX=002Fh
----------2F54-------------------------------
INT 2F U - ???
    AH = 54h
    AL = subfunction (00h, 01h, maybe others???)
Return: ???
Note:    called by MS Windows 3.1 POWER.DRV
SeeAlso: AH=53h
----------2F5453-----------------------------
INT 2F - TesSeRact RAM-RESIDENT PROGRAM INTERFACE
    AX = 5453h
    BX = subfunction
        00h installation check
        CX = 0000h
        DS:SI -> 8-char blank-padded name
        Return: AX = FFFFh installed
                CX = ID number of already-installed copy
               = anything else, not installed
                CX = ID number for TSR when installed
        01h get user parameters
        CX = TSR ID number
        Return: AX = 0000h successful
               ES:BX -> user parameter block (see below)
               = nonzero failed
        02h check if hotkey in use
        CL = scan code of hot key
        Return: AX = FFFFh hot key conflicts with another TSR
                 otherwise safe to use the hotkey
        03h replace default critical error handler
        CX = TSR ID number
        DS:SI -> new routine for INT 24h
        Return: AX = nonzero, unable to install new handler
        04h get internal data area
        CX = TSR ID number
        Return: AX = 0000h
                ES:BX -> TSR's internal data area (see below)
               = nonzero, TSR not found
        05h set multiple hot keys
        CX = TSR ID number
        DL = number of additional hot keys to allocate
        DS:SI -> table of hot keys
            BYTE  hotkey scan code
            BYTE  hotkey shift state
            BYTE  flag value to pass to TSR (nonzero)
        Return: AX = nonzero, unable to install hot keys
        06h - 0Fh reserved
        10h enable TSR
        CX = TSR ID number
        Return: AX = nonzero, unable to enable
        11h disable TSR
        CX = TSR ID number
        Return: AX = nonzero, unable to disable
        12h unload TSR
        CX = TSR ID number
        Return: AX = nonzero, invalid TSR number
        Note: if any interrupts used by TSR have been grabbed by
            another TSR, the TesSeRact routines will wait until
            it is safe to remove the indicated TSR from memory
        13h restart TSR
        CX = TSR ID number of TSR which was unloaded but is still in
             memory
        Return: AX = nonzero, unable to restart TSR
        14h get status word
        CX = TSR ID number
        Return: AX = FFFFh invalid ID number
               = other, successful
                BX = bit flags
        15h set status word
        CX = TSR ID number
        DX = new bit flags
        Return: AX = nonzero, unable to set status word
        16h get INDOS state at popup
        CX = TSR ID number
        Return: AX = 0000h successful
                BX = value of INDOS flag
        17h - 1Fh reserved
        20h call user procedure
        CX = TSR ID number
        ES:DI -> user-defined data
        Return: AX = 0000h successful
        21h stuff keystrokes into keyboard buffer
        CX = TSR ID number
        DL = speed
            00h stuff keystrokes only when buffer is empty
            01h stuff up to four keystrokes per clock tick
            02h stuff up to 15 keystrokes per clock tick
        DH = scan code flag
            if zero, buffer contains alternating ASCII and scan codes
            if nonzero, buffer contains only ASCII codes
        SI = number of keystrokes
        ES:DI -> buffer to stuff
        Return: AX = 0000h success
                 F0F0h user aborted with ^C or ^Break
                 other unable to stuff keystrokes
        22h (v1.10) trigger popup
        CX = TSR ID number
        Return: AX = 0000h success, TSR will either pop up or beep to
                   indicate that it is unable to pop up
                 nonzero invalid ID number
        23h (v1.10) invoke TSR's background function
        CX = TSR ID number
        Return: AX = 0000h success
                 FFFFh not safe to call background function
                 nonzero invalid ID number
        24h - 2Fh reserved
Notes:    Borland's THELP.COM popup help system for Turbo Pascal and Turbo C
      (versions 1.x and 2.x only) fully supports the TesSeRact API, as
      do the SWAP?? programs by Innovative Data Concepts.
    AVATAR.SYS supports functions 00h and 01h (only the first three fields
      of the user parameter block) using the name "AVATAR  "
SeeAlso: AX=CAFEh

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

Format of TSR internal data area:
Offset    Size    Description
 00h    BYTE    revision level of TesSeRact library
 01h    BYTE    type of popup in effect
 02h    BYTE    INT 08 occurred since last invocation
 03h    BYTE    INT 13 occurred since last invocation
 04h    BYTE    active interrupts
 05h    BYTE    active soft interrupts
 06h    BYTE    DOS major version
 07h    BYTE    how long to wait before popping up
 08h    DWORD    pointer to INDOS flag
 0CH    DWORD    pointer to DOS critical error flag
 10h    WORD    PSP segment of interrupted program
 12h    WORD    PSP segment of prog interrupted by INT 28
 14h    DWORD    DTA of interrupted program
 18h    DWORD    DTA of program interrupted by INT 28
 1Ch    WORD    SS of interrupted program
 1Eh    WORD    SP of interrupted program
 20h    WORD    SS of program interrupted by INT 28
 22h    WORD    SP of program interrupted by INT 28
 24h    DWORD    INT 24 of interrupted program
 28h  3 WORDs    DOS 3+ extended error info
 2Eh    BYTE    old BREAK setting
 2Fh    BYTE    old VERIFY setting
 30h    BYTE    were running MS WORD 4.0 before popup
 31h    BYTE    MS WORD 4.0 special popup flag
 32h    BYTE    enhanced keyboard call in use
 33h    BYTE    delay for MS WORD 4.0
11 times (for INTs 08h,09h,13h,16h,1Ch,21h,28h,2Fh,1Bh,23h, and 24h):
    DWORD    old interrupt vector
    BYTE    interrupt number
    WORD    offset in TesSeRact code segment of new interrupt handler
----------2F5500-----------------------------
INT 2F U - DOS v5.0 - COMMAND.COM INTERFACE
    AX = 5500h
Return: AX = 0000h
    DS:SI -> entry point table
Notes:    used to access the shareable portion of COMMAND.COM, which may have
      been moved into the HMA; only the primary COMMAND.COM retains this
      portion
    procedures called from a dispatcher in COMMAND's resident portion;
      most assume that the segment address of the resident portion is on
      the stack and are thus not of general use
----------2F6282-----------------------------
INT 2F U - PC Tools v7.0+ VDEFEND, VSAFE, VWATCH, DATAMON - SET ??? ADDRESS
    AX = 6282h
    CX:DX -> ??? or 0000h:0000h
    DI = 0000h ???
         FFFFh ???
         other segment of ???
Return: BX = 0062h
Note:    if CX:DX = 0000h:0000h on entry, the ??? address is not changed
      (DATAMON only)
SeeAlso: INT 13/AH=FAh"VSAFE",INT 21/AH=FAh"VDEFEND"
----------2F6284BX0000-----------------------
INT 2F U - PC Tools v7.0+ DATAMON - INSTALLATION CHECK
    AX = 6284h
    BX = 0000h
    CX = 0000h
Return: AX = segment of resident code
    BX = 5555h
    CX = 5555h
----------2F6284BX0001-----------------------
INT 2F U - PC Tools v7.0+ DATAMON - GET ???
    AX = 6284h
    BX = 0001h
    CX = 0001h
Return: AX:BX -> ???
    CX = BX
----------2F6284BX0002-----------------------
INT 2F U - PC Tools v7.0+ DATAMON - GET ???
    AX = 6284h
    BX = 0002h
    CX = 0002h
Return: AX = ???
    BX = ???
    CX = AX
    DX = BX
----------2F6284BX0003-----------------------
INT 2F U - PC Tools v7.0+ DATAMON - SET ??? FLAGS
    AX = 6284h
    BX = 0003h
    CX = flags
        bit 12: ???
        10: ???
         5: ???
         3: ???
    DX = flags
        bit 15: ???
----------2F6284BX0004-----------------------
INT 2F U - PC Tools v8.0+ DATAMON - ???
    AX = 6284h
    BX = 0004h
    CX = 0004h
Return: AX = 5555h
    BX = ??? (0800h)
    CX = ??? (FCCCh)
----------2F6400-----------------------------
INT 2F - SCRNSAV2.COM - INSTALLATION CHECK
    AX = 6400h
Return: AL = 00h not installed
         FFh installed
Note:    SCRNSAV2.COM is a screen saver for PS/2's with VGA by Alan Ballard
SeeAlso: INT 10/AX=5555h
----------2F7000------------------------------
INT 2F - License Service API - INSTALLATION CHECK
    AX = 7000h
    CX = license server index (0000h to 001Fh)
Return: AL = status
        00h not installed
        FFh installed
Notes:    The License Service API is being maintained by Microsoft but is being
      supported by a large number of companies including Apple, Banyan,
      DEC, HP, Lotus, Microsoft, Novell, Software Publishers Association,
      and Wordperfect (not a complete list!)
    Each license service provider must search for the next free index
      slot to use
SeeAlso: AX=7001h,AX=7003h,AX=7004h,AX=7005h
----------2F7001------------------------------
INT 2F - License Service API - REQUEST License
    AX = 7001h
    CX = license server index (0000h to 001Fh)
    DS:DX -> SLSREQEUST structure (see below)
Return: AX = status
        0000h success
        else  provider error code
    ES:BX = provider specific handle for the license context
SeeAlso: AX=7002h,AX=7004h,AX=7005h

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

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

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

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

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

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

Format of device driver header:
Offset    Size    Description
 00h 10 BYTEs    same as standard device driver header (see INT 21/AH=52h)
 0Ah    BYTE    number of subunits (drives) supported by driver
 0Bh  3 BYTEs    signature "SRD"
 0Eh  4 BYTEs    memory type string (currently only "XMS ")
 12h  4 BYTEs    ASCII driver version string "N.NN"
 16h    BYTE    00h
 17h    BYTE    configuration format version (currently 00h)
 18h    WORD    offset of drive configuration data
----------2F7A00-----------------------------
INT 2F - Novell NetWare - LOW-LEVEL API (IPX) INSTALLATION CHECK
    AX = 7A00h
Return: AL = 00h not installed
       = FFh installed
        ES:DI -> FAR entry point for routines accessed exclusively
            through INT 7A in NetWare versions through 2.0a.  Call
            with same values as INT 7A
SeeAlso: AX=7AFFh/BX=0000h,AX=D800h,INT 64"Novell",INT 7A"Novell"
----------2F7A10-----------------------------
INT 2F - Novell NetWare - TBMI v2.0 - GET TBMI STATUS
    AX = 7A10h
Return: DH = major TBMI version number
    DL = minor TBMI version number
    CX = segment address of TBMI resident part
    BX = status word of TBMI
        bit 0: INT2F intercepted by TBMI
        bit 1: INT7A intercepted by TBMI
        bit 2: INT64 intercepted by TBMI
        bits 3-14: reserved or unused ???
        bit 15: outstanding task ID was detected
Note:    TBMI is the Task-Switched Buffer Manager Interface
SeeAlso: AX=7A11h,AX=7A12h,AX=7A13h,AX=7A14h
----------2F7A11-----------------------------
INT 2F - Novell NetWare - TBMI v2.0 - GET INT2F HANDLERS
    AX = 7A11h
Return: ES:BX -> old INT 2F handler
    DS:DX -> TBMI INT 2F handler
SeeAlso: AX=7A10h,AX=7A12h,AX=7A13h
----------2F7A12-----------------------------
INT 2F - Novell NetWare - TBMI v2.0 - GET INT64 HANDLERS
    AX = 7A12h
Return: ES:BX -> old INT 64 handler
    DS:DX -> TBMI INT 64 handler
SeeAlso: AX=7A10h,AX=7A11h,AX=7A13h
----------2F7A13-----------------------------
INT 2F - Novell NetWare - TBMI v2.0 - GET INT7A HANDLERS
    AX = 7A13h
Return: ES:BX = old INT 7A handler
    DS:DX = TBMI INT 7A handler
SeeAlso: AX=7A10h,AX=7A11h,AX=7A12h
----------2F7A14-----------------------------
INT 2F - Novell NetWare - TBMI v2.0 - GET STATISTICS
    AX = 7A14h
    CX = statistic to retrieve
        0000h available diagnostic functions???
        Return: CX = maximum available function??? (000Ch for v2.0)
        0001h buffers in use
        Return: CX = TBMI buffers currently in use
        0002h maximum buffers used
        Return: CX = maximum number of buffers ever in use
        0003h unavailable buffers
        Return: CX = count of unavailable TBMI buffers
        0004h old interrupt usage
        Return: CX = TBMI accesses to intercepted old vectors INT 2F,
                INT 64, and INT 7A
        0005h far call usage
        Return: CX = TBMI accesses to IPX/SPX far call handler (not
                including internal accesses)
        0006h task buffering
        Return: CX = TBMI task buffering status (enabled/disabled or
                disable/enable switch count???)
        0007h current task ID
        Return: CX = TBMI current task ID number (0000h if ???)
        0008h outstanding ID count
        Return: CX = number of outstanding TBMI IDs
        0009h configured ECBs
        Return: CX = number of TBMI Event Control Blocks configured
        000Ah configured data ECBs
        Return: CX = number of TBMI data ECBs configured
        000Bh configured sockets
        Return: CX = number of TBMI sockets configured (from NETCFG)
        000Ch current sockets
        Return: CX = number of TBMI sockets currently in use
SeeAlso: AX=7A10h
----------2F7A1B-----------------------------
INT 2F - Novell NetWare - TBMI v2.0 - RESERVED???
    AX = 7A1Bh
Note:    this call merely performs an IRET
----------2F7A20-----------------------------
INT 2F - Novell NetWare - NetWare 4.0 DOS Requester - GET CALL ADDRESS
    AX = 7A20h
    BX = 0000h
Return: AX = 0000h on success
        ES:BX -> far call address for DOS Requester
Note:    the DOS Requester replaces the NetWare Shell (ANETx, NETx) on
      NetWare LAN's as of the release of NetWare 4.0.  It is backward
      compatible with NetWare 2.1x through 3.11 servers as well.
----------2F7A80-----------------------------
INT 2F C - Novell NetWare - SHELL 3.01d BROADCAST - ABNORMAL EXIT
    AX = 7A80h
Return: nothing
Notes:    called on abnormal exit of the NetWare shell to notify other Novell
      TSRs that it is unsafe to call the shell in the future.
    must be passed through so that all interested programs see the exit
    on receiving this call, IPXODI clears an internal pointer to a
      default value; Novell's NETBIOS.EXE clears its INT 21h pointer to
      0000h:0000h and stops calling it
SeeAlso: AX=7A81h
----------2F7A81-----------------------------
INT 2F - Novell NetWare - SHELL 3.01d BROADCAST - SET SHELL INT 21 HANDLER
    AX = 7A81h
    CX:DX -> shell's INT 21h entry point
Return: nothing
Notes:    the shell calls this function as it loads to allow interested TSRs
      and drivers to make a local copy of the shell's entry point
    must be passed through so that all interested programs see it
----------2F7A85-----------------------------
INT 2F - Novell NetWare - shell 3.01 - BROADCAST INFORM
    AX = 7A85h
    CX = broadcast server number
Return: CX = 0000h if broadcast message handled by another program
    CX unchanged if broadcast not handled
----------2F7A90-----------------------------
INT 2F U - Novell NetWare - NETBIOS.EXE 3+ - INSTALLATION CHECK
    AX = 7A90h
Return: AL = 00h if present
        BX = ???
        CX = PSP segment of NETBIOS resident code
SeeAlso: AX=7AFEh
----------2F7AFE-----------------------------
INT 2F - Novell NetWare - DOSNP.EXE - INSTALLATION CHECK
    AX = 7AFEh
Return: AL = FFh if present
        ES = (data???) segment of DOSNP
Program: DOSNP.EXE provides "named pipes" support for DOS workstations running
       NetWare
Note:    the NetWare shell calls this function and refuses to load if DOSNP is
      present
SeeAlso: AX=7A90h
----------2F7AFFBX0000-----------------------
INT 2F - Novell NetWare - TBMI v2.0 - INSTALLATION CHECK???
    AX = 7AFFh
    BX = 0000h
    CX = 4E65h ("Ne")
    DX = 7457h ("tW")
    ES:DI -> IPX/SPX special handler (XMS/EMS ???)
Return: AL = FFh if installed
        CX = configured sockets (14h)
        DS:SI -> data table ???
        ES:DI -> IPX far call handler
Note:    for IPX/SPX this call reportedly returns DS:DI pointing to the table
      of pointers to service events queue head and tail
SeeAlso: AX=7AFFh/BX=0001h
----------2F7AFFBX0001-----------------------
INT 2F - Novell NetWare - TBMI v2.0, shell v3.01d - INSTALLATION CHECK???
    AX = 7AFFh
    BX = 0001h
    CX = 4E65h ("Ne")
    DX = 7457h ("tW")
Return: AL = FFh if installed
        CX = ???  (8000h)
        SI = ??? (or -> ???) (0002h)
        ES:DI -> IPX far call handler
        ES:DX -> 6-byte data area ???
SeeAlso: AX=7AFFh/BX=0000h
----------2F7F24-----------------------------
INT 2F - Multiplex - ???
    AX = 7F24h
    ???
Return: ???
Note:    called by PC/370, an IBM 370 emulator by Donald S. Higgins
----------2F7F26-----------------------------
INT 2F - Multiplex - ???
    AX = 7F26h
    ???
Return: ???
Note:    called by PC/370, an IBM 370 emulator by Donald S. Higgins
----------2F8000-----------------------------
INT 2F - EASY-NET - INSTALLATION CHECK
    AX = 8000h
Return: AL = 00h not installed
         FFh installed
Note:    EASY-NET is a shareware two-machine serial-port network
----------2F8000-----------------------------
INT 2F - Nanosoft, Inc. TurboNET server - INSTALLATION CHECK
    AX = 8000h
Return: AL = FFh if installed
        BX = CS of resident code
        CX = ??? (03FCh)
Note:    TurboNET is a NetBIOS-based file redirector and server; a demonstration
      version may be downloaded from Nanosoft's BBS
SeeAlso: AX=8100h
----------2F8000DX0000-----------------------
INT 2F - FaxBIOS interface - INSTALLATION CHECK
    AX = 8000h
    DX = 0000h
    DI = 0000h
Return: AL = FFh if installed
    DX:DI -> signature "FaxBiosjpc"
Note:    FaxBIOS may use any multiplex number from 80h through FFh; to determine
      whether it is installed, it is necessary to poll all multiplex
      numbers for one which returns the above signature
SeeAlso: AH=2Ah,AX=80FBh
----------2F8001-----------------------------
INT 2F - Nanosoft, Inc. TurboNET server - ???
    AX = 8001h
    DS:SI -> 16-byte buffer for ???
Return: AH = status
        00h successful
        01h error
Note:    makes NetBIOS calls
----------2F80FB-----------------------------
INT 2F - FaxBIOS interface - COMMAND SUBMISSION
    AX = 80FBh
    BX = function number (see below)
    DX:DI -> command buffer (see below)
Return: AL = FFh if submitted OK
    CX = result code (see below)
Note:    FaxBIOS may use any multiplex number from 80h through FFh
SeeAlso: AX=8000h"FaxBIOS",AX=CBDDh

Values for function number:
 0001h    SYS_LOGIN
 0002h    SYS_LOGOUT
 0003h    SYS_GET_FAXAPP_INFO
 0004h    STAT_IO_GET
 0005h    STAT_FAXBIOS_GET
 0006h    PDIR_OPEN
 0007h    PDIR_CLOSE
 0008h    PDIR_READ_PERSON
 0009h    PDIR_PARTIAL_READ
 000Ah    PDIR_READ_GROUP
 000Bh    PDIR_READ_MEMBER_LIST
 000Ch    PDIR_WRITE_PERSON
 000Dh    PDIR_WRITE_GROUP
 000Eh    PDIR_DELETE_PERSON
 000Fh    PDIR_DELETE_GROUP
 0010h    PDIR_READ_GROUP_LIST
 0011h    PDIR_IN_GROUP
 0012h    PDIR_OUT_GROUP
 0013h    SCHED_OPEN
 0014h    SCHED_ADD_DEST
 0015h    SCHED_ADD_FILE
 0016h    SCHED_SET_PARAMS
 0017h    SCHED_CANCEL
 0018h    SCHED_CLOSE
 0019h    SLOG_OPEN
 001Ah    SLOG_CLOSE
 001Bh    SLOG_SHORT_ENV_STAT
 001Ch    SLOG_LONG_ENV_STAT
 001Dh    SLOG_DEST_STAT
 001Eh    SLOG_FILE_STAT
 001Fh    SLOG_CANCEL_ENV
 0020h    RLOG_OPEN
 0021h    RLOG_CLOSE
 0022h    RLOG_READ
 0023h    GRAPH_GET_FILE_TYPE
 0024h    GRAPH_EXPORT_FILE
 0025h    GRAPH_GET_LAYOUT_INFO
 0026h    GRAPH_CREATE_FILE
 0027h    GRAPH_CLOSE_FILE
 0028h    GRAPH_CREATE_PAGE
 0029h    GRAPH_WRITE
 002Ah    GRAPH_END_PAGE
 002Bh    GRAPH_OPEN_FILE
 002Ch    GRAPH_GOTO_PAGE
 002Dh    GRAPH_READ
 002Eh    IOCTL_GET
 002Fh    IOCTL_SET
 0030h    IOCTL_ANSWER_FAX
 0031h    IOCTL_DIAL

Values for result code:
 0000h    successful
 0001h    not prepared or servicing another client (busy)
 0002h    call failed due to sharing (LOCKED)
 0003h    logged-in client limit reached (FULL)
 0004h    transport denied (TRANSPORT_DENIED)
 0005h    not implemented (NOT_IMPLEMENTED)
 0006h    aborted while in progress (ABORTED)
 0007h    permissions denied (PERMISSION_DENIED)
 0008h    requested data is no longer valid (NO_LONGER_VALID)
 0080h    unspecified system error occurred
 0081h    an internal file was not found
 0082h    an internal file could not be created
 0083h    an internal file could not be opened
 0084h    an internal file could not be closed
 0085h    error occurred writing to an internal file
 0086h    error occurred reading from an internal file
 0087h    bad or corrupted file encountered
 0088h    an access violation occurred
 0089h    an internal file is empty
 008Ah    insufficient memory to process request
 008Bh    FaxBIOS was unable to issue a handle
 008Ch    an error internal to FaxBIOS occurred
 008Dh    no room on disk
 0100h    unspecified error accessing client file
 0101h    file not found
 0102h    creation fault
 0103h    open fault
 0104h    close fault
 0105h    write fault
 0106h    read fault
 0107h    file corrupted
 0108h    access violation
 0109h    empty file
 0200h    unspecified argument error
 0201h    bad function
 0202h    bad option
 0203h    bad structure size
 0204h    bad buffer size
 0205h    bad client ID
 0300h    unspecified error with token
 0301h    cover sheet token was invalid
 0302h    logo token was invalid
 0303h    signature token was invalid
 0304h    font token was invalid
 0305h    phone directory token was invalid
 0306h    outbound route token was invalid
 0307h    priority token was invalid
 0308h    sort token was invalid
 0309h    billing token was invalid
 0400h    unspecified handle error
 0401h    bad Phone Directory handle
 0402h    bad scheduling handle
 0403h    bad read send log handle
 0404h    bad read receive log handle
 0405h    bad graphics handle
 0500h    data passed in structure was invalid
 0501h    name field given is invalid
 0502h    phone number given is invalid
 0503h    poll code submitted is invalid
 0504h    file type constant was invalid
 0505h    BFT constant not defined or supported
 0506h    resolution not defined or supported
 0507h    page length not defined or supported
 0508h    page width not defined or supported
 0509h    date & time requested are ridiculous
 050Ah    Subject text was not an ASCIIZ string
 050Bh    From text was not an ASCIIZ string
 050Ch    requested envelope ID was not found
 050Dh    requested envelope ID is not valid
 050Eh    envelope requested was not found
 050Fh    destination index is out of range
 0510h    file index is out of range
 0511h    index into receive log is out of range
 0512h    file name specified was incomplete or invalid
 0513h    page selected was out of range
 0514h    bit width more than byte width
 0515h    mode for open is not defined
 0516h    person index is out of range
 0517h    person ID is out of range
 0518h    group index out of range or invalid
 0519h    group ID out of range or invalid
 051Ah    range of indices to read is invalid
 051Bh    group name given is invalid
 051Ch    field_to_use is badly specified
 051Dh    predicate invalid for field specified
 0600h    unspecified client procedure error
 0601h    device of interest is not present
 0602h    device of interest has been removed
 0603h    device of interest is not responding
 0604h    device of interest is disabled
 0605h    could not dial because device was in use
 0606h    maximum destination limit exceeded
 0607h    maximum file limit exceeded
 0608h    scheduling closed with no destination
 0609h    scheduling closed with no files or poll
 060Ah    scheduling closed with no parameters specified
 060Bh    file type specified does not match file
 060Ch    file type specified is not supported
 060Dh    file submitted is not exportable
 060Eh    file type specified is not imageable
 060Fh    error converting file
 0610h    envelope could not be cancelled
 0611h    Phone Directory is full
 0612h    record is already in the Phone Directory
 0613h    selected group in Phone Directory is full
 0614h    person is already in the group
 0615h    person is not in the group & cannot be removed
 0616h    a graphics file to be created already exists
 0617h    a grphics file to be read is empty
 0618h    GRAPH_CREATE_PAGE called before GRAPH_END_PAGE
 0619h    graph read or write attempted without goto or create
 061Ah    graph page contains no data
 061Bh    Phone Directory is already open for this client
 061Ch    schedule log is already open for this client
 061Dh    receive log is aready open for this client
 061Eh    Phone Directory function requires write mode
 0800h    denied exclusive use of the API

Format of SYS_LOGIN command buffer:
Offset    Size    Description
 00h    WORD    structure size
 02h    WORD    function number
 04h    WORD    return code
 06h    WORD    client ID
 08h    WORD    API Major Version
 0Ah    WORD    API Minor Version
 0Ch    DWORD    reserved for manufacturer's use
 10h 22 BYTEs    manufacturer's ID
 26h    WORD    highest possible device number
 28h    WORD    maximum destinations per envelope
 2Ah    WORD    maximum files per envelope
 2Ch    WORD    FaxBIOS capabilities bitmap
        bit 0: transmit supported
        bit 1: receive supported
        bit 2: IOCTL supported
        bit 3: IOCTL_DIAL supported
        bit 4: IOCTL_ANSWER_FAX supported
        bit 5: manual transmit supported
        bit 6: optional phone services supported
        bit 7: canonical phone objects
        bit 8: seam with next supported
 2Eh    DWORD    T.30 capabilities bitmap
        bit 0:    low vertical resolution (minimum)
        bit 1:    high vertical resolution
        bit 2:    page width 107mm (4.21 in)
        bit 3:    page width 151mm (5.91 in)
        bit 4:    page width 215mm (8.46 in) (minimum)
        bit 5:    page width 255mm (10.04 in)
        bit 6:    page width 303mm (11.93 in)
        bit 7:    unused
        bit 8:    page length 297mm (11.69 in) (minimum)
        bit 9:    page length 364mm (14.33 in)
        bit 10: page length 279mm (11 in)
        bit 11: page length unlimited
        bit 12: Group 4 resolution 300x300
        bit 13: Group 4 resolution 400x400
        bit 14: able to respond to poll from remote
        bit 15: able to poll remote
        bit 16: binary file transfer supported
 32h    WORD    IPC handle
 34h    DWORD    amount of memory needed to load
 38h    WORD    scope (00h for public, nonzero for private)
 3Ah  6 BYTEs    future expansion
 40h    WORD    structure size

Format of SYS_LOGOUT command buffer:
Offset    Size    Description
 00h    WORD    structure size
 02h    WORD    function number
 04h    WORD    return code
 06h    WORD    client ID
 08h    DWORD    client tag (for client's internal use)
 0Ch  6 BYTEs    future expansion
 12h    WORD    structure size

Format of SYS_GET_FAXAPP_INFO command buffer:
Offset    Size    Description
 00h 12 BYTEs    common data (see SYS_LOGOUT above)
 0Ch 80 BYTEs    FaxBIOS data
 5Ch 80 BYTEs    default cover
 ACh 80 BYTEs    default logo
 FCh 80 BYTEs    default signature
14Ch 80 BYTEs    default font 10
19Ch 80 BYTEs    default font 165
1ECh 80 BYTEs    default user font
23Ch 80 BYTEs    default Pdir
28Ch 80 BYTEs    default sort
2DCh 10 BYTEs    default bill
2E6h 10 BYTEs    default route
2F0h 40 BYTEs    default cover sheet form
318h 34 BYTEs    valid dial characters
33Ah  6 BYTEs    local country code
340h  6 BYTEs    local city or area code
346h  6 BYTEs    future expansion
34Ch    WORD    structure size

Format of STAT_IO_GET command buffer:
Offset    Size    Description
 00h 12 BYTEs    common data (see SYS_LOGOUT above)
 0Ch    WORD    device number
 0Eh    WORD    current activity
 10h    WORD    number of rings (if ringing)
 12h    WORD    number of fascimiles transmitted
 14h    WORD    number of fascimiles received
 16h    WORD    status of last transmission
 18h    WORD    envelope number of last transmission
 1Ah    WORD    index of last destination in envelope
 1Ch    WORD    status of last reception
 1Eh    WORD    current page (if session in progress)
 20h 80 BYTEs    current file
 70h104 BYTEs    remote number
 D8h 20 BYTEs    last name
 ECh 20 BYTEs    first name
100h 32 BYTEs    company name
120h 32 BYTEs    notes
140h    WORD    current envelope ID (if sending)
142h    WORD    total pages in transmission (if sending)
144h  6 BYTEs    future expansion
14h    WORD    structure size

Format of STAT_FAXBIOS_GET command buffer:
Offset    Size    Description
 00h 12 BYTEs    common data (see SYS_LOGOUT above)
 0Ch    WORD    status ID
 0Eh    WORD    currenty FaxBIOS function number
 10h    WORD    current Client ID being serviced
 12h    WORD    number of things to do
 14h    WORD    number of them done
 16h    WORD    number of pages to do (if any)
 18h    WORD    number of them done
 1Ah    WORD    number of files to do
 1Ch    WORD    number of them done
 1Eh 80 BYTEs    current File
 6Eh    WORD    0 if all devices are idle
 70h    WORD    number of fascimiles transmitted
 72h    WORD    number of fascimiles received
 74h    WORD    status of last transmission in system
 76h    WORD    envelope ID of last transmission
 78h    WORD    index of last destination in envelope
 7Ah    WORD    status of last reception in system
 7Ch    DWORD    time of next transmission
 80h  6 BYTEs    future expansion
 86h    WORD    structure size

Format of PDIR_OPEN command buffer:
Offset    Size    Description
 00h 12 BYTEs    common data (see SYS_LOGOUT above)
 0Ch 80 BYTEs    Phone Directory token
 5Ch 80 BYTEs    sort order token
 ACh    WORD    open Mode (0 = read, 1 = write)
 AEh    WORD    Phone Directory handle
 B0h    WORD    number of people
 B2h    WORD    number of groups
 B4h    WORD    bitmap of fields supported by partial read
 B6h  6 BYTEs    future expansion
 BCh    WORD    structure size

Format of PDIR_CLOSE command buffer:
Offset    Size    Description
 00h 12 BYTEs    common data (see SYS_LOGOUT above)
 0Ch    WORD    Phone Directory handle
 0Eh  6 BYTEs    future expansion
 14h    WORD    structure size

Format of PDIR_READ_PERSON command buffer:
Offset    Size    Description
 00h 12 BYTEs    common data (see SYS_LOGOUT above)
 0Ch    WORD    Phone Directory handle
 0Eh    WORD    retrieve by index
 10h    WORD    person ID or index
 12h    WORD    how many groups person is in
 14h    WORD    person ID
 16h 20 BYTEs    last name
 2Ah 20 BYTEs    first name
 3Eh 32 BYTEs    company
 5Eh 32 BYTEs    notes
 7Eh  6 BYTEs    FAX country code
 84h  6 BYTEs    FAX city/area code
 8Ah 14 BYTEs    FAX local number
 98h 14 BYTEs    FAX extension
 A6h 24 BYTEs    reserved
 BEh  6 BYTEs    voice country code
 C4h  6 BYTEs    voice city/area code
 CAh 14 BYTEs    voice local number
 D8h 14 BYTEs    voice extension
 E6h 24 BYTEs    reserved
 FEh 10 BYTEs    outbound routing information
108h 10 BYTEs    billing information, credit card etc
112h    DWORD    remote FAX capabilities
116h 21 BYTEs    T.30 poll code of FAX number
12Bh 15 BYTEs    reserved
13Ah  6 BYTEs    future expansion
140h    WORD    structure size

Format of SCHED_OPEN, SCHED_CANCEL command buffer:
Offset    Size    Description
 00h 12 BYTEs    common data (see SYS_LOGOUT above)
 0Ch    WORD    scheduler handle
 0Eh  6 BYTEs    future expansion
 14h    WORD    structure size

Format of SCHED_ADD_DEST command buffer:
Offset    Size    Description
 00h 12 BYTEs    common data (see SYS_LOGOUT above)
 0Ch    WORD    schedule handle
 0Eh    WORD    device number if manual send wanted
 10h    WORD    non-zero if poll desired
 12h    WORD    person ID
 14h 20 BYTEs    last name
 28h 20 BYTEs    first name
 3Ch 32 BYTEs    company
 5Ch 32 BYTEs    notes
 7Ch  6 BYTEs    FAX country code
 82h  6 BYTEs    FAX city/area code
 88h 14 BYTEs    FAX local number
 96h 14 BYTEs    FAX extension
 A4h 24 BYTEs    reserved
 BCh  6 BYTEs    voice country code
 C2h  6 BYTEs    voice city/area code
 C8h 14 BYTEs    voice local number
 D6h 14 BYTEs    voice extension
 E4h 24 BYTEs    reserved
 FCh 10 BYTEs    outbound routing information
106h 10 BYTEs    billing information, credit card etc
110h    DWORD    remote FAX capabilities
114h 21 BYTEs    T.30 poll code of FAX number
129h 15 BYTEs    reserved
138h  6 BYTEs    future expansion
13Eh    WORD    structure size

Format of SCHED_ADD_FILE command buffer:
Offset    Size    Description
 00h 12 BYTEs    common data (see SYS_LOGOUT above)
 0Ch    WORD    schedule handle
 0Eh    WORD    file type
        0000h unidentified
        0001h native file format
        0002h ASCII
        0003h FaxBIOS Tiff Class F
 10h 80 BYTEs    file name
 60h 80 BYTEs    font token
 B0h    WORD    conversion options bitmap
 B2h    WORD    resolution
        0000h standard 98 lines per inch, 204 dpi
        0001h fine 196 lines per inch, 204 dpi
        0002h Group4 300 dpi
        0003h Group4 400 dpi
 B4h    WORD    page length
        0000h 279 mm (11 in)
        0001h 297 mm (11.69 in)
        0002h 364 mm (14.33 in)
        0003h unlimited
 B6h    WORD    page width
        0000h 215 mm (8.46 in)
        0001h 255 mm (10.04 in)
        0002h 303 mm (11.93 in)
        0003h 151 mm (5.91 in)
        0004h 107 mm (4.21 in)
 B8h    WORD    binary file transfer specification
        0000h only as FAX
        0001h only as file (for non-faxable files)
        0002h as file when possible else FAX
 BAh    WORD    seam flag (nonzero for seam with next)
 BCh    WORD    delete flag (nonzero to delete when done)
 BEh  6 BYTEs    future expansion
 C4h    WORD    structure size

Format of SCHED_SET_PARAMS command buffer:
Offset    Size    Description
 00h 12 BYTEs    common data (see SYS_LOGOUT above)
 0Ch    WORD    scheduler handle
 0Eh    DWORD    time to send
 10h 10 BYTEs    priority token
 1Ch 80 BYTEs    logo file token
 6Ch 80 BYTEs    signature file token
 BCh 80 BYTEs    cover page token
10Ch 40 BYTEs    Subject text
134h 40 BYTEs    From text
15Ch    WORD    user ID
15Eh  6 BYTEs    future expansion
164h    WORD    structure size

Format of SCHED_CLOSE command buffer:
Offset    Size    Description
 00h 12 BYTEs    common data (see SYS_LOGOUT above)
 0Ch    WORD    scheduler handle
 0Eh    WORD    envelope ID generated
 10h  6 BYTEs    future expansion
 16h    WORD    structure size

Format of SLOG_OPEN, SLOG_CLOSE, RLOG_OPEN, RLOG_CLOSE command buffer:
Offset    Size    Description
 00h 12 BYTEs    common data (see SYS_LOGOUT above)
 0Ch    WORD    log handle
 0Eh    WORD    number of entries
 10h  6 BYTEs    future expansion
 16h    WORD    structure size

Format of GRAPH_GET_FILE_TYPE command buffer:
Offset    Size    Description
 00h 12 BYTEs    common data (see SYS_LOGOUT above)
 0Ch 80 BYTEs    filename
 5Ch    WORD    file type
        0000h unidentified
        0001h native file format
        0002h ASCII
        0003h FaxBIOS Tiff Class F
 5Eh    WORD    bitmap of supported capabilities
 60h  6 BYTEs    future expansion
 66h    WORD    structure size

Format of GRAPH_CREATE_FILE command buffer:
Offset    Size    Description
 00h 12 BYTEs    common data (see SYS_LOGOUT above)
 0Ch 80 BYTEs    filename
 5Ch    WORD    graph handle
 5Eh  6 BYTEs    future expansion
 64h    WORD    structure size

Format of GRAPH_CLOSE_FILE, GRAPH_END_PAGE command buffer:
Offset    Size    Description
 00h 12 BYTEs    common data (see SYS_LOGOUT above)
 0Ch    WORD    graph handle
 0Eh  6 BYTEs    future expansion
 14h    WORD    structure size

Format of GRAPH_CREATE_PAGE command buffer:
Offset    Size    Description
 00h 12 BYTEs    common data (see SYS_LOGOUT above)
 0Ch    WORD    graph handle
 0Eh    WORD    resolution
 10h    WORD    page width
 12h  6 BYTEs    future expansion
 18h    WORD    structure size

Format of GRAPH_WRITE_PAGE command buffer:
Offset    Size    Description
 00h 12 BYTEs    common data (see SYS_LOGOUT above)
 0Ch    WORD    graph handle
 0Eh    DWORD    pointer to storage for image
 12h    WORD    band height in lines
 14h    WORD    width of page image in bytes
 16h    WORD    facsimile page width constant
 18h    WORD    width of page image in bits
 1Ah    WORD    number of bytes actually processed
 1Ch  6 BYTEs    future expansion
 22h    WORD    structure size

Format of GRAPH_OPEN_FILE command buffer:
Offset    Size    Description
 00h 12 BYTEs    common data (see SYS_LOGOUT above)
 0Ch 80 BYTEs    filename
 5Ch    WORD    file type
 5Eh    WORD    graph handle
 60h    WORD    number of pages
 62h  6 BYTEs    future expansion
 68h    WORD    structure size

Format of GRAPH_GOTO_PAGE command buffer:
Offset    Size    Description
 00h 12 BYTEs    common data (see SYS_LOGOUT above)
 0Ch    WORD    graph handle
 0Eh    WORD    page number
 10h    WORD    vertical resolution
 12h    WORD    page width
 14h    DWORD    page length
 18h  6 BYTEs    future expansion
 1Eh    WORD    structure size

Format of GRAPH_READ_PAGE command buffer:
Offset    Size    Description
 00h 12 BYTEs    common data (see SYS_LOGOUT above)
 0Ch    WORD    graph handle
 0Eh    DWORD    pointer to storage for image
 12h    WORD    band height in lines
 14h    WORD    width of page image in bytes
 16h    WORD    facsimile page width constant
 18h    WORD    width of page image in bits
 1Ah    WORD    number of bytes actually processed
 1Ch  6 BYTEs    future expansion
 22h    WORD    structure size

Format of IOCTL_ANSWER_FAX command buffer:
Offset    Size    Description
 00h 12 BYTEs    common data (see SYS_LOGOUT above)
 0Ch    WORD    device number
 0Eh  6 BYTEs    future expansion
 14h    WORD    structure size

Format of IOCTL_DIAL command buffer:
Offset    Size    Description
 00h 12 BYTEs    common data (see SYS_LOGOUT above)
 0Ch    WORD    device number
 0Eh  6 BYTEs    country code
 14h  6 BYTEs    city or area code
 1Ah 14 BYTEs    local number
 28h 14 BYTEs    extension
 36h 14 BYTEs    reserved
 4Eh  6 BYTEs    future expansion
 54h    WORD    structure size
----------2F8100-----------------------------
INT 2F U - Nanosoft, Inc. TurboNET redirector - INSTALLATION CHECK
    AX = 8100h
Return: AL = FFh if installed
Note:    TurboNET is a NetBIOS-based file redirector and server; a demonstration
      version may be downloaded from Nanosoft's BBS
SeeAlso: AX=8000h"TurboNET"
----------2F8101-----------------------------
INT 2F U - Nanosoft, Inc. TurboNET redirector - ???
    AX = 8101h
Return: AL = ???
    DL = ???
----------2F8102-----------------------------
INT 2F U - Nanosoft, Inc. TurboNET redirector - ???
    AX = 8102h
Return: AL = ???
    DL = ???
----------2F8103-----------------------------
INT 2F U - Nanosoft, Inc. TurboNET redirector - GET MACHINE NAME???
    AX = 8103h
    ES:DI -> 17-byte buffer
Return: buffer filled
----------2F8104-----------------------------
INT 2F U - Nanosoft, Inc. TurboNET redirector - ???
    AX = 8104h
    BL = ???
    BH = ???
    CX = ???
    DX = ???
    DS:SI -> 16-byte buffer containing ???
Return: AL = 00h ???
----------2F8105-----------------------------
INT 2F U - Nanosoft, Inc. TurboNET redirector - ???
    AX = 8105h
    CX = ??? (don't change current value if 0000h)
    DX = ??? (don't change current value if 0000h)
Return: AL = 00h successful
----------2F82-------------------------------
INT 2F U - Nanosoft, Inc. TurboNET - ???
    AH = 82h
    ???
Return: ???
Note:    called by TNR.EXE, the TurboNET redirector configuration program
SeeAlso: AX=8100h
----------2F8200-----------------------------
INT 2F - RESPLAY - SAMPLE/PLAYBACK
    AX = 8200h
    DX:DI -> start of sample space
    CX:BX = length in bytes
Return: AX = status
        1000h successful
        2000h not initialized (see AX=8210h)
        other RESPLAY not installed
Note:    RESPLAY is a freeware sound sampling/playback utility by Mark J. Cox
SeeAlso: AX=8201h,AX=8210h
----------2F8201-----------------------------
INT 2F - RESPLAY - INSTALLATION CHECK
    AX = 8201h
Return: AX = 7746h if installed
SeeAlso: AX=8202h
----------2F8202-----------------------------
INT 2F - RESPLAY - UNINSTALL
    AX = 8202h
Return:    AX = status
        1000h successful
SeeAlso: AX=8201h
----------2F8210-----------------------------
INT 2F - RESPLAY - INITIALIZE
    AX = 8210h
    BL = sound device
        00h printer port LPT1
        01h printer port LPT2
        02h prototype board at I/O address 0300h
        03h printer port (alternative LPT1)
        04h internal speaker
    BH = sample rate in multiples of 250 Hz (14h to A0h)
    CL = direction
        00h playback
        01h sample
Return: AX = status
        1000h successful
        2000h parameter out of range
        other RESPLAY not installed
SeeAlso: AX=8200h
----------2F86-------------------------------
INT 2F U - ???
    AH = 86h
    AL = function (at least 06h and 07h)
    ???
Return: ???
Note:    called by Codeview for Windows
SeeAlso: AH=44h
----------2F8900-----------------------------
INT 2F - WHOA!.COM - INSTALLATION CHECK
    AX = 8900h
Return: AL = 00h not installed
       = FFh installed
Note:    WHOA!.COM is a system slow-down utility by Brad D Crandall
SeeAlso: AX=8901h,AX=8902h
----------2F8901-----------------------------
INT 2F - WHOA!.COM - UNINSTALL
    AX = 8901h
Return: AL = FDh successful
       = FEh error
Note:    WHOA!.COM is a system slow-down utility by Brad D Crandall
SeeAlso: AX=8900h
----------2F8902-----------------------------
INT 2F - WHOA!.COM - SET DELAY COUNT
    AX = 8902h
    BX = delay count (larger values slow system down more)
Return: AL = FDh successful
       = FEh error
Note:    WHOA!.COM is a system slow-down utility by Brad D Crandall
SeeAlso: AX=8900h
----------2F9000-----------------------------
INT 2F U - RAID - INSTALLATION CHECK
    AX = 9000h
Return: AL = FFh if installed
Note:    RAID (Resident AID) is a TSR utility program by Ross Neilson Wentworth
      that resides mostly in EMS
----------2F9001-----------------------------
INT 2F U - RAID - GET ???
    AX = 9001h
Return: DX:AX -> ???
SeeAlso: AX=9000h
----------2F9002-----------------------------
INT 2F U - RAID - GET RESIDENT SEGMENT
    AX = 9002h
Return: AX = segment of resident (conventional memory) portion
SeeAlso: AX=9000h
----------2F9003-----------------------------
INT 2F U - RAID - UNINSTALL
    AX = 9003h
Return: ???
SeeAlso: AX=9000h
----------2F9004-----------------------------
INT 2F U - RAID - GET ???
    AX = 9004h
Return: AX = first available paragraph past end of resident portion???
    CX destroyed
SeeAlso: AX=9000h
----------2F92-------------------------------
INT 2F - Couriers LAN E-Mail - API
    AH = 92h
    AL = function
        00h installation check
        01h uninstall
        02h pop down MICRO.EXE notification window
        03h ???
        04h ???
        05h ???
Return: ???
SeeAlso: AH=9Ch
----------2F92-------------------------------
INT 2F U - PC Tools v8.0 DRIVEMAP - ???
    AH = 92h
    AL = function (00h-1Eh)
    ???
Return: ???
    AX = FFFFh if not a valid function number in AL
SeeAlso: INT 16/AX=FF70h
----------2F93-------------------------------
INT 2F - InnerMission v1.7+ - INSTALLATION CHECK
    AH = 93h
    BX = CX = AX
Return: AL = FFh if installed and BX=CX=AX on entry
        BX = segment of resident code
       = 01h if installed but BX or CX differ from AX
Note:    InnerMission is a shareware graphical screen blanker by Kevin Stokes
----------2F9C-------------------------------
INT 2F - Couriers LAN E-Mail OPERATOR.EXE - API
    AH = 9Ch
    AL = subfunction
        01h uninstall
Return: ???
SeeAlso: AH=92h
----------2FA1--BX0081-----------------------
INT 2F - Ergo DOS extenders - INSTALLATION CHECK
    AH = A1h
    BX = 0081h
    AL = which
        FEh OS/286,OS/386
        FFh HummingBoard DOS extender
    ES:DI -> 16-byte buffer
Return: if installed, first four bytes of ES:DI buffer are "IABH"
Note:    since TKERNEL is a licensed version, it is likely that subfunctions
      BX=0082h and BX=0084h are present and function identically to the
      AX=FBA1h/BX=008xh calls
SeeAlso: AX=ED00h,AX=FBA1h,INT 15/AX=BF02h
----------2FA189-----------------------------
INT 2F U - Biologic HRAMDEV.SYS - API
    AX = A189h
    BX = subfunction
        0000h set ???
        0001h remove ???
        0002h get status ???
        0003h enable ???
        0004h disable ???
        0005h set ??? flag
        0006h clear ??? flag
        0007h set ??? flag
        0008h clear ??? flag
        0009h set ???
    ES:DI -> function-specific arguments
        if func 0000h: 20-byte buffer containing ???
        if func 0001h: 20-byte buffer for returned ???
        if func 0002h: 16-byte buffer for returned ???
        if func 0009h: WORD containing ???
Return: BX = A189h if installed
    AH = status
        00h successful
        FFh failed or invalid function number
Notes:    HRAMDEV.SYS is a part of the shareware package HRAM by Biologic which
      provides improved high memory access under MSDOS 5.0
    functions 00h and 01h use a stack of four entries; function 01h always
      removes the values stored with the most recent function 00h call
      which has not yet been matched with a function 01h call.
----------2FA4E0-----------------------------
INT 2F - Futurus Team - INSTALLATION CHECK
    AX = A4E0h
Return: AL = 52h ("R") if installed
        AH = major version plus 30h ("0")
        ES:BX -> ??? (INT A4 handler???)
Note:    older versions of Right Hand Man (from which Team evolved) store the
      signature "RH" at offset 103h in the INT 2F handler's segment
SeeAlso: INT A4"Right Hand Man"
----------2FA900-----------------------------
INT 2F - METZTSR.COM - INSTALLATION CHECK
    AX = A900h
    CF set
Return: CF clear if resident
        AX = 97FFh
    CF set if not present
Notes:    METZTSR.COM prevents METZ applications (such as the MAGIC screen
      saver) inactivity timeout while running a DOSapp under MS Windows.
    the default multiplex number is A9h, but may be set to any value from
      80h to FFh with a commandline switch
SeeAlso: AX=A901h,AX=A902h
----------2FA901-----------------------------
INT 2F - METZTSR.COM - GET TIME OF LAST KEYBOARD ACTIVITY
    AX = A901h
    CF set
Return: CF clear if successful
        AX:DX = BIOS time at which INT 09 was last invoked
    CF set if not present
SeeAlso: INT 09,INT 1A/AH=00h
----------2FA902-----------------------------
INT 2F - METZTSR.COM - SET METZ Ctrl-Alt-Del FLAG
    AX = A902h
    BL = new value
        00h Ctrl-Alt-Del not allowed
        else Ctrl-Alt-Del allowed (startup default is 01h)
    CF set
Return: CF clear if successful
        AX = 97FFh
    CF set if not resident
SeeAlso: AX=A903h
----------2FA903-----------------------------
INT 2F - METZTSR.COM - GET METZ Ctrl-Alt-Del FLAG
    AX = A903h
    CF set
Return: CF clear if successful
        AX = 97FFh if Ctrl-Alt-Del allowed
        AX = 0000h if Ctrl-Alt-Del not allowed
    CF set if not resident
SeeAlso: AX=A902h
----------2FAA00-----------------------------
INT 2F - VIDCLOCK.COM - INSTALLATION CHECK
    AX = AA00h
Return: AL = 00h not installed
         FFh installed
Note:    VIDCLOCK.COM is a memory-resident clock by Thomas G. Hanlin III
----------2FAB00-----------------------------
INT 2F - Btrieve Multi-User - INSTALLATION CHECK
    AX = AB00h
Return: AL = 4Dh if installed
SeeAlso: AX=AB01h,AX=AB02h,INT 7B"Btrieve"
----------2FAB01-----------------------------
INT 2F - Btrieve Multi-User - EXECUTE Btrieve OPERATION
    AX = AB01h
    BX = process ID
    DS:DX -> 38-byte parameter record (see INT 7B"Btrieve")
Return: AL = 00h OK
       = other retry after calling INT 7F/AX=0200h
SeeAlso: AX=AB00h,AX=AB02h,INT 7B"Btrieve",INT 7F/AX=0200h
----------2FAB02-----------------------------
INT 2F - Btrieve Multi-User - GET NEW PROCESS ID
    AX = AB02h
Return: AL = 00h succesful
        BX = process ID
    AL > 00h failed, retry after calling INT 7F/AX=0200h
SeeAlso: AX=AB00h,AX=AB01h,INT 7B"Btrieve",INT 7F/AX=0200h
----------2FAC00-----------------------------
INT 2F - DOS 4.01+ GRAPHICS.COM - INSTALLATION CHECK
    AX = AC00h
Return: AX = FFFFh
    ES:DI -> ??? (graphics data?) (not documented)
Note:    this installation check was moved here to avoid the conflict with the
      CD-ROM extensions that occurred in DOS 4.00
SeeAlso: AX=1500h"GRAPHICS"
----------2FAD00-----------------------------
INT 2F U - DOS 3.3+ DISPLAY.SYS internal - INSTALLATION CHECK
    AX = AD00h
Return: AL = FFh if installed
        BX = ??? (0100h in MS-DOS 3.30, PCDOS 4.01)
Note:    DOS 5.0 DISPLAY.SYS chains to previous handler if AL is not one of the
      subfunctions listed here
----------2FAD01-----------------------------
INT 2F U - DOS 3.3+ DISPLAY.SYS internal - SET ACTIVE CODE PAGE
    AX = AD01h
    BX = new code page
Return: CF clear if successful
        AX = 0001h
    CF set on error (unsupported code page)
        AX = 0000h
SeeAlso: AX=AD02h
----------2FAD02-----------------------------
INT 2F U - DOS 3.3+ DISPLAY.SYS internal - GET ACTIVE CODE PAGE
    AX = AD02h
Return: CF set if code page never set
        AX = 0001h
        BX = FFFFh (assume first hardware code page)
    CF clear if successful
        BX = current code page
SeeAlso: AX=AD01h,AX=AD03h
----------2FAD03-----------------------------
INT 2F U - DOS 3.3+ DISPLAY.SYS internal - GET CODE PAGE INFORMATION
    AX = AD03h
    ES:DI -> buffer for code page information (see below)
    CX = size of buffer in bytes
Return: CF set if buffer too small
    CF clear if successful
        ES:DI buffer filled
SeeAlso: AX=AD01h,AX=AD02h

Format of DOS 5.0 code page information:
Offset    Size    Description
 00h    WORD    number of software code pages
 02h    WORD    ??? (0003h)
 04h    WORD    number of hardware code pages
 06h  N WORDs    hardware code page numbers
      N WORDs    software (prepared) code pages (FFFFh if not yet prepared)
----------2FAD04-----------------------------
INT 2F U - DOS 4.x only DISPLAY.SYS internal - ???
    AX = AD04h
    ???
Return: ???
----------2FAD10-----------------------------
INT 2F U - DOS 4.x DISPLAY.SYS internal - INSTALLATION CHECK???
    AX = AD10h
    ???
Return: AX = FFFFh
    BX = ??? (0100h in PCDOS 4.01)
----------2FAD10-----------------------------
INT 2F U - DOS 5.0 DISPLAY.SYS internal - ???
    AX = AD10h
    ???
Return: CF clear if successful
    CF set on error
Note:    this function is a NOP if the active code page has never been set
      (AX=AD02h returns BX=FFFFh); its purpose otherwise is not known
----------2FAD40-----------------------------
INT 2F - DOS 4.0 - ???
    AX = AD40h
    DX = ???
    ???
Return: ???
Note:    called by PCDOS 4.01 PRINT.COM
----------2FAD80-----------------------------
INT 2F u - DOS 3.3+ KEYB.COM internal - INSTALLATION CHECK
    AX = AD80h
Return: AL = FFh if installed
        BX = version number (BH = major, BL = minor)
        ES:DI -> internal data (see below)
Notes:    MSDOS 3.30, PCDOS 4.01, and MSDOS 5.00 all report version 1.00.
    undocumented prior to the release of DOS 5.0

Format of KEYB internal data:
Offset    Size    Description
 00h    DWORD    original INT 09
 04h    DWORD    original INT 2F
 08h  6 BYTEs    ???
 0Eh    WORD    flags
 10h    BYTE    ???
 11h    BYTE    ???
 12h  4 BYTEs    ???
 16h  2 BYTEs    country ID letters
 18h    WORD    current code page
---DOS 3.3---
 1Ah    WORD    pointer to first item in list of code page tables???
 1Ch    WORD    pointer to ??? item in list of code page tables
 1Eh  2 BYTEs    ???
 20h    WORD    pointer to key translation data
 22h    WORD    pointer to last item in code page table list (see below)
 24h  9 BYTEs    ???
---DOS 4.01---
 1Ah  2 BYTEs    ???
 1Ch    WORD    pointer to first item in list of code page tables???
 1Eh    WORD    pointer to ??? item in list of code page tables
 20h  2 BYTEs    ???
 22h    WORD    pointer to key translation data
 24h    WORD    pointer to last item in code page table list (see below)
 26h  9 BYTEs    ???

Format of code page table list entries:
Offset    Size    Description
 00h    WORD    pointer to next item, FFFFh = last
 02h    WORD    code page
 04h  2 BYTEs    ???

Format of translation data:
Offset    Size    Description
 00h    WORD    size of data in bytes, including this word
 02h N-2 BYTEs    ???
----------2FAD81-----------------------------
INT 2F - DOS 3.3+ KEYB.COM - SET KEYBOARD CODE PAGE
    AX = AD81h
    BX = code page (see INT 21/AX=6601h)
Return: CF set on error
        AX = 0001h (code page not available)
    CF clear if successful
Notes:    called by DISPLAY.SYS
    undocumented prior to the release of DOS 5.0
SeeAlso: AX=AD82h
----------2FAD82-----------------------------
INT 2F - DOS 3.3+ KEYB.COM - SET KEYBOARD MAPPING
    AX = AD82h
    BL = new state
        00h US keyboard (Control-Alt-F1)
        FFh foreign keyboard (Control-Alt-F2)
Return: CF set on error (BL not 00h or FFh)
    CF clear if successful
Note:    undocumented prior to the release of DOS 5.0
SeeAlso: AX=AD81h,AX=AD83h
----------2FAD83-----------------------------
INT 2F - DOS 5.0 KEYB.COM - GET KEYBOARD MAPPING
    AX = AD83h
Return: BL = current state
        00h US keyboard
        FFh foreign keyboard
SeeAlso: AX=AD82h
----------2FAE00DXFFFF-----------------------
INT 2F U - DOS 3.3+ internal - INSTALLABLE COMMAND - INSTALLATION CHECK
    AX = AE00h
    DX = FFFFh
    CH = FFh
    CL = length of command line tail (4DOS v4.0)
    DS:BX -> command line buffer (see below)
    DS:SI -> command name buffer (see below)
    DI = 0000h (4DOS v4.0)
Return: AL = FFh if this command is a TSR extension to COMMAND.COM
    AL = 00h if the command should be executed as usual
Notes:    This call provides a mechanism for TSRs to install permanent
      extensions to the command repertoire of COMMAND.COM.    It appears
      that COMMAND.COM makes this call before executing the current
      command line, and does not execute it itself if the return is FFh.
    APPEND hooks this call, to allow subsequent APPEND commands to
      execute without re-running APPEND

Format of command line buffer:
Offset    Size    Description
 00h    BYTE    max length of command line, as in INT 21/AH=0Ah
 01h    BYTE    count of bytes to follow, excluding terminating 0Dh
      N BYTEs    command line text, terminated by 0Dh

Format of command name buffer:
Offset    Size    Description
 00h    BYTE    length of command name
 01h  N BYTEs    uppercased command name (blank-padded to 11 chars by 4DOS v4)
----------2FAE01DXFFFF-----------------------
INT 2F U - DOS 3.3+ internal - INSTALLABLE COMMAND - EXECUTE
    AX = AE01h
    DX = FFFFh
    CH = 00h
    CL = length of command name (4DOS v4.0)
    DS:SI -> command name buffer (see AX=AE00h)
    DS:BX -> command line buffer (see AX=AE00h)
Return: DS:SI buffer updated
      if length byte is nonzero, the following bytes contain the uppercase
      internal command to execute and the command line buffer contains the
      command's parameters (the first DS:[SI] bytes are ignored)
Notes:    this call requests execution of the command which a previous call to
      AX=AE00h indicated was resident
    APPEND hooks this call
----------2FB000-----------------------------
INT 2F - DOS 3.3+ GRAFTABL.COM - INSTALLATION CHECK
    AX = B000h
Return: AL = 00h not installed, OK to install
       = 01h not installed, not OK to install
       = FFh installed
Notes:    called by DISPLAY.SYS
    documented for DOS 5.0, but undocumented in prior versions
SeeAlso: AX=B001h
----------2FB001-----------------------------
INT 2F - DOS 3.3+ GRAFTABL.COM - GET GRAPHICS FONT TABLE
    AX = B001h
    DS:BX -> DWORD buffer for address of 8x8 font table
Return: buffer filled
    AL = FFh
Note:    PCDOS 3.30/4.01 set the font table offset to 0130h, MSDOS 3.30 to 0030h
SeeAlso: AX=B000h
----------2FB400-----------------------------
INT 2F - IBM PC3270 EMULATION PROG v3 - INSTALLATION CHECK
    AX = B400h
Return: AL = FFh if installed
----------2FB401-----------------------------
INT 2F - IBM PC3270 EMULATION PROG v3 - GET HOST BUFFER ADDRESS
    AX = B401h
Return: ES -> host screen buffer (PC ASCII format)
    ES unchanged if communications not started
----------2FB402-----------------------------
INT 2F - IBM PC3270 EMULATION PROG v3 - ???
    AX = B402h
    BX = ???
Return: ???
----------2FB403-----------------------------
INT 2F - IBM PC3270 EMULATION PROG v3 - ???
    AX = B403h
    ???
Return: ???
----------2FB404-----------------------------
INT 2F - IBM PC3270 EMULATION PROG v3 - ???
    AX = B404h
    ???
Return: ???
----------2FB405-----------------------------
INT 2F - IBM PC3270 EMULATION PROG v3 - ???
    AX = B405h
    ???
Return: ???
----------2FB700-----------------------------
INT 2F - APPEND - INSTALLATION CHECK
    AX = B700h
Return: AL = status
        00h not installed
        FFh installed
Note:    MSDOS 3.30 APPEND refuses to install itself when run inside TopView or
      a TopView-compatible environment
----------2FB701-----------------------------
INT 2F U - APPEND - ???
    AX = B701h
    ???
Return: ???
Note:    MSDOS 3.30 APPEND displays "Incorrect APPEND Version" and aborts caller
----------2FB702-----------------------------
INT 2F - APPEND - VERSION CHECK
    AX = B702h
Return: AX = FFFFh if not DOS 4.0 APPEND (also if DOS 5.0 APPEND)
    AL = major version number
    AH = minor version number, otherwise
SeeAlso: AX=B710h
----------2FB703-----------------------------
INT 2F U - DOS 3.3, DOS 5.0 APPEND - HOOK INT 21
    AX = B703h
    ES:DI -> INT 21 handler APPEND should chain to
Return: ES:DI -> APPEND's INT 21 handler
Note:    each invocation of this function toggles a flag which APPEND uses to
      determine whether to chain to the user handler or the original
      INT 21
----------2FB704-----------------------------
INT 2F - DOS 3.3+ APPEND - GET APPEND PATH
    AX = B704h
Return: ES:DI -> active APPEND path (128 bytes max)
----------2FB706-----------------------------
INT 2F - DOS 4+ APPEND - GET APPEND FUNCTION STATE
    AX = B706h
Return: BX = APPEND state
        bit 0: set if APPEND enabled
        bits 1-11 reserved
        bit 12: (DOS 5.0) set if APPEND applies directory search even if a
            drive has been specified
        bit 13: set if /PATH flag active
        bit 14: set if /E flag active (environment var APPEND exists)
        bit 15: set if /X flag active
----------2FB707-----------------------------
INT 2F - DOS 4+ APPEND - SET APPEND FUNCTION STATE
    AX = B707h
    BX = APPEND state bits (see AX=B706h)
----------2FB710-----------------------------
INT 2F U - DOS 3.3+ APPEND - GET VERSION INFO
    AX = B710h
Return: AX = current APPEND state (see AX=B706h)
    BX = ??? (0000h in MSDOS 3.30 and 5.00)
    CX = ??? (0000h in MSDOS 3.30 and 5.00)
    DL = major version
    DH = minor version
SeeAlso: AX=B702h
----------2FB711-----------------------------
INT 2F - DOS 4+ APPEND - SET RETURN FOUND NAME STATE
    AX = B711h
Note:    if the next INT 21h call (and ONLY the next) is function 3Dh, 43h, or
    6Ch (also 4B03h and 4Eh if /X active), the fully qualified filename is
    written over top of the filename passed to the INT 21h call.  The
    application must provide a sufficiently large buffer.  This state is
    reset after the next INT 21h call processed by APPEND.
BUG:    DOS 4.0 APPEND reportedly overwrites DS:DX instead of DS:SI for
      INT 21/AH=6Ch
SeeAlso: INT 21/AH=4Eh
----------2FB800-----------------------------
INT 2F - network - INSTALLATION CHECK
    AX = B800h
Return: AL = status
        00h        not installed
        nonzero installed
          BX = installed component flags (test in this order!)
           bit 6   server
           bit 2   messenger
           bit 7   receiver
           bit 3   redirector
           bit 1   LANPUP (LANtastic 4.0)
Notes:    this function is supported by SilverNET
    LANtastic and NetWare Lite use only BL for the return value, preserving
      BH; LAN Manager and DOS LAN Requester return BH=0.  This permits
      differentiation between those two groups by setting BH to a nonzero
      value before the call and checking its value on return.
SeeAlso: AX=4E53h,AX=B809h
----------2FB803-----------------------------
INT 2F - network - GET NETWORK EVENT POST HANDLER
    AX = B803h
Return: ES:BX -> event post handler (see AX=B804h)
SeeAlso: AX=B804h,AX=B903h
----------2FB804-----------------------------
INT 2F - network - SET NETWORK EVENT POST HANDLER
    AX = B804h
    ES:BX -> new event post handler
Notes:    used in conjunction with AX=B803h to hook into the network event post
      routine
    The specified handler is called on any network event.  Two events are
      defined: message received and critical network error.
SeeAlso: AX=B803h,AX=B904h

Values post routine is called with:
    AX = 0000h single block message
        DS:SI -> ASCIZ originator name
        DS:DI -> ASCIZ destination name
        ES:BX -> text header (see below)
    AX = 0001h start multiple message block
        CX = block group ID
        DS:SI -> ASCIZ originator name
        DS:DI -> ASCIZ destination name
    AX = 0002h multiple block text
        CX = block group ID
        ES:BX -> text header (see below)
    AX = 0003h end multiple block message
        CX = block group ID
    AX = 0004h message aborted due to error
        CX = block group ID
    AX = 0101h server received badly formatted network request
        Return: AX = FFFFh (PC LAN will process error)
    AX = 0102h unexpected network error
        ES:BX -> NCB (see INT 5C)
    AX = 0103h server received INT 24 error
        other registers as for INT 24, except AH is in BH
        Return: as below, but only 0000h and FFFFh allowed
Return:    AX = response code
        0000h user post routine processed message
        0001h PC LAN will process message, but message window not displayed
        FFFFh PC LAN will process message

Format of text header:
Offset    Size    Description
 00h    WORD    length of text (maximum 512 bytes)
 02h  N BYTEs    text of message
Note:    all CRLF sequences in message text are replaced by 14h
----------2FB807-----------------------------
INT 2F - Network - GET NetBIOS NAME NUMBER OF MACHINE NAME
    AX = B807h
Return: CH = NetBIOS name number of the machine name
SeeAlso: INT 21/AX=5E00h
----------2FB808-----------------------------
INT 2F U - Network - RELINK KEYBOARD HANDLER
    AX = B808h
    ES:BX -> INT 09 handler network should call after it finishes INT 09
Notes:    this call replaces the address to which the network software chains on
      an INT 09 without preserving the original value.  This allows a prior
      handler to unlink, but does not allow a new handler to be added
      such that the network gets the INT 09 first unless the new handler
      completely takes over INT 09 and never chains.
    called by DOS 3.2 KEYBxx.COM
SeeAlso: AX=B908h
----------2FB809-----------------------------
INT 2F - LANtastic Network, NetWare Lite - VERSION CHECK
    AX = B809h
Return: AH = major version
    AL = minor version (decimal)
Note:    this function is also supported by SilverNET
SeeAlso: AX=4E53h,AX=B800h,AX=B809h"LAN Manager"
----------2FB809-----------------------------
INT 2F - PC LAN Program, LAN Manager, DOS LAN Requester - VERSION CHECK
    AX = B809h
Return: AH = minor version (decimal)
    AL = major version
SeeAlso: AX=4E53h,AX=B800h,AX=B809h"LANtastic"
----------2FB80F-----------------------------
INT 2F - DOS LAN Requester - GET START PARAMETERS
    AX = B80Fh
    CX = size of return data buffer
    ES:DI -> return data buffer
Return: AX = status
         00h     network started
         nonzero network not started
    CX = number of bytes returned in buffer
    ES:DI buffer filled

Format of return data buffer:
Offset    Size    Description
 00h    BYTE    major version
 01h    BYTE    minor version
 02h    WORD    configuration flags given when the network was started
        bit 0  /NVS != 0
        bit 1  /NMS != 0
        bit 2  /API
        bit 3  /HIM
        bit 4  /LIM
        bit 5  /ENC
        bit 6  /POP
        bit 7  /EMS
        bit 8  /RPL
        bits 9-12 Reserved
        bit 13    RDR started
        bit 14    RCV started
        bit 15    User is currently logged on
 04h 15 BYTEs    NET START machine name (space padded)
 13h    BYTE    00h
 14h 9    BYTEs    NET START domain name (NULL padded)
 1Dh    BYTE    00h
 1Eh 32 BYTEs    /WRK heuristics string (space padded, not terminated)
 3Eh    WORD    /SRV value
 40h    WORD    /ASG value
 42h    WORD    /NBC value
 44h    WORD    /NBS value
 46h    WORD    /BBC value
 48h    WORD    /BBS value
 4Ah    WORD    /PBC value
 4Ch    WORD    /PBS value
 4Eh    WORD    /PFS value
 50h    WORD    /PFT value
 52h    WORD    /PWT value
 54h    WORD    /KUC value
 56h    WORD    /KST value
 58h    WORD    /NVS value
 5Ah    WORD    /NMS value
 5Ch    WORD    /NDB value
 5Eh    WORD    /MBI value
 60h    BYTE    NetBIOS name number for machine name
 61h    BYTE    NetBIOS name number for domain name
 62h    WORD    NetBIOS sessions required for configuration
 64h    WORD    NetBIOS commands required for configuration
 66h    WORD    NetBIOS names required for configuration
 68h 128 BYTEs    NET START path (LANROOT)
 E8h    BYTE    00h
----------2FB900-----------------------------
INT 2F - PC Network RECEIVER.COM - INSTALLATION CHECK
    AX = B900h
Return: AL = 00h if not installed
         FFh if installed
----------2FB901-----------------------------
INT 2F - PC Network RECEIVER.COM - GET RECEIVER.COM INT 2F HANDLER ADDRESS
    AX = B901h
Return: AL = ???
    ES:BX -> RECEIVER.COM INT 2F handler
Note:    allows more efficient execution by letting the caller bypass any other
      INT 2F handlers which have been added since RECEIVER.COM was
      installed
----------2FB903-----------------------------
INT 2F - PC Network RECEIVER.COM - GET RECEIVER.COM POST ADDRESS
    AX = B903h
Return: ES:BX -> POST handler
SeeAlso: AX=B803h,AX=B904h
----------2FB904-----------------------------
INT 2F - PC Network RECEIVER.COM - SET RECEIVER.COM POST ADDRESS
    AX = B904h
    ES:BX -> new POST handler
SeeAlso: AX=B804h,AX=B903h
----------2FB905-----------------------------
INT 2F - PC Network RECEIVER.COM - GET FILENAME
    AX = B905h
    DS:BX -> 128-byte buffer for filename 1
    DS:DX -> 128-byte buffer for filename 2
Return: buffers filled from RECEIVER.COM internal buffers
Note:    use of filenames is unknown, but one appears to be for storing messages
SeeAlso: AX=B906h
----------2FB906-----------------------------
INT 2F - PC Network RECEIVER.COM - SET FILENAME
    AX = B906h
    DS:BX -> 128-byte buffer for filename 1
    DS:DX -> 128-byte buffer for filename 2
Return: RECEIVER.COM internal buffers filled from user buffers
Note:    use of filenames is unknown, but one appears to be for storing messages
SeeAlso: AX=B905h
----------2FB908-----------------------------
INT 2F - PC Network RECEIVER.COM - UNLINK KEYBOARD HANDLER
    AX = B908h
    ES:BX -> INT 09 handler RECEIVER should call after it finishes INT 09
Note:    this call replaces the address to which RECEIVER.COM chains on an
      INT 09 without preserving the original value.     This allows a prior
      handler to unlink, but does not allow a new handler to be added
      such that RECEIVER gets the INT 09 first.
SeeAlso: AX=B808h
----------2FBC00-----------------------------
INT 2F - Windows 3.0, DOS 5.0 EGA.SYS - INSTALLATION CHECK
    AX = BC00h
Return: AL = 00h not installed, OK to install
       = 01h not installed, not OK to install
       = FFh installed
        BX = 5456h ("TV")
Note:    AH=BCh is the default value, which may be changed by a command line
      parameter to any value between 80h and FFh
SeeAlso: AX=BC06h,INT 10/AH=FAh"EGA"
----------2FBC06-----------------------------
INT 2F U - MS Windows 3.0, DOS 5.0 EGA.SYS - GET VERSION INFO
    AX = BC06h
Return: BX = 5456h ("TV")
    CH = major version
    CL = minor version
    DL = revision
SeeAlso: AX=BC00h,INT 10/AH=FAh"EGA"
----------2FBE00-----------------------------
INT 2F - REDVIEW - INSTALLATION CHECK
    AX = BE00h
Return: AL = FFh if installed
Note:    REDVIEW is a public-domain TSR by Alexandr Novy and Petr Horak which
      copies data sent to standard output to standard error when the
      former has been redirected to a file, thus allowing the data to
      be seen on the screen at the same time it is captured in a file
----------2FBF00-----------------------------
INT 2F - PC LAN PROGRAM REDIRIFS.EXE internal - INSTALLATION CHECK
    AX = BF00h
Return: AL = FFh if installed
----------2FBF01-----------------------------
INT 2F U - PC LAN PROGRAM REDIRIFS.EXE internal - ???
    AX = BF01h
    ???
Return: ???
----------2FBF80-----------------------------
INT 2F - PC LAN PROG REDIR.SYS internal - SET REDIRIFS ENTRY POINT
    AX = BF80h
    ES:DI -> FAR entry point to IFS handler in REDIRIFS
Return: AL = FFh if installed
        ES:DI -> internal workspace
Note:    all future IFS calls to REDIR.SYS are passed to the ES:DI entry point
---------------------------------------------