Note: This API call is for DOS personality only. Use Family API for portability.

2018/09/07 07:04 · prokushev

Int 21H, AH=30H


2 and higher



Family API


      AH = 30h

—DOS 5+ —

      AL = what to return in BH
          00h OEM number (see #01394)
          01h version flag


AL = major version number (00h if DOS 1.x)

      AH = minor version number
      BL:CX = 24-bit user serial number (most versions do not use this)

—if DOS <5 or AL=00h—

      BH = MS-DOS OEM number (see #01394)

—if DOS 5+ and AL=01h—

      BH = version flag
          bit 3: DOS is in ROM
          other: reserved (0)


Notes: the OS/2 v1.x Compatibility Box returns major version 0Ah (10)

      the OS/2 v2.x Compatibility Box returns major version 14h (20)
      OS/2 Warp 3.0 Virtual DOS Machines report v20.30; Warp 4 VDMs report
      the Windows NT DOS box returns version 5.00, subject to SETVER
      DOS 4.01 and 4.02 identify themselves as version 4.00; use
        INT 21/AH=87h to distinguish between the original European MS-DOS 4.0
        and the later PC-DOS 4.0x and MS-DOS 4.0x
      IBM DOS 6.1 reports its version as 6.00; use the OEM number to
        distinguish between MS-DOS 6.00 and IBM DOS 6.1 (there was never an
        IBM DOS 6.0)
      IBM's PC DOS 7 and Y2K updates report themselves as IBM 7.0 to be
        distinguished from the MS-DOS 7.0 portion of Windows 95.
      MS-DOS 6.21 reports its version as 6.20; version 6.22 returns the
        correct value
      Windows95 returns version 7.00 (the underlying MS-DOS), as did the
        "Chicago" beta (reported in _Microsoft_Systems_Journal_,August 1994);
        Windows95 OSR2 and OSR2.5 (OPK3) return MS version 7.10
      DR DOS 5.0 and 6.0 report version 3.31; Novell DOS 7 reports IBM v6.00,
        which some software displays as IBM DOS v6.10 (because of the version
        mismatch in true IBM DOS, as mentioned above).  The Novell DOS 7
        SETVER.EXE has an undocumented option /G x.y which sets the "global"
        DOS version returned by this function for all executables not given
        a specific version number in SETVER to major version x and minor
        version y.
      Heiko Goeman's Advanced WinDOS 2.10/2.11/2.21 returns "IBM" DOS 5.00
        (subject to SETVER) and serial number 0.
      All versions of CCI Multiuser DOS up to "CCI Multiuser DOS 7.22 Gold"
        as of 1997-02-10 report DOS 3.31.
      DR DOS 3.31, 3.32, 3.33, 3.34, 3.35, 3.40, 3.41, 5.0, 6.0 and
        DR PalmDOS/NetWare PalmDOS 1.0 report version 3.31;
        DR DOS "Panther" BETA 1 and "StarTrek" report as 5.0.
        Novell DOS 7, OpenDOS 7.01, DR-OpenDOS 7.02, DR-DOS 7.02, DR-DOS 7.03
        all report themselves as IBM 6.00, which some software displays as
        IBM DOS 6.10 (because of the version mismatch in true IBM DOS,
        as mentioned above). Use INT 21/AX=4452h to distinguish the DR-DOS
        family from PC DOS.
      The Novell DOS 7 and OpenDOS 7.01 SETVER.EXE has an undocumented
        option /G x.y which sets the "global" DOS version returned by this
        function for all executables not given a specific version number in
        SETVER to major version x >= 5 and minor version y = 0..254,
        y = 255 is used to disable the BDOS version check at INT 21/AX=4452h.
      A slightly modified option has been documented for DR-OpenDOS 7.02+:
        in /X mode it now allows for x >= 1, while y >= 100 requires /X mode,
        and y >= 128 is used to control advanced version control means now
        (see below).
      DR-DOS 7.02+ IBMDOS.COM (since 1998-01-10) now recognizes optional
        paths to filenames stored in the SETVER list. Previously such entries
        were never found. This allows for a three staged model for SETVERed
        highest priority = entry with path is matching.
        middle priority = entry without path is matching.
        lowest priority = use global version (SETVER /G).
      The DR-DOS 7.02+ SETVER 1.01+ (1998-01-12) has also been enhanced to
        allow DOS *and* BDOS version faking (see INT 21/AX=4452h): In /X mode,
        setting a sub-version of y = 128..255 will be reported as 0..127 DOS
        sub-version, sub-versions of y = 100..127 will instead be used to
        report this value as BDOS version (64h..7Fh) via INT 21/AX=4452h, and
        the DOS revision stored in PCM_HEADER in the IBMDOS.COM file will
        be used to report the DOS sub-version (usually this holds 0, but it
        can be patched to other values, see INT 21/AX=4452h !!!).
        Note, that DR-DOS SHARE 2.05+ (1998-01-05) has relaxed version
        checking, and will install on any DOS revision 0..127, as long as
        run on a DR-DOS 72h+ kernel (formerly it was bound to a revision
        byte of 0 only).
      Under Novell DOS 7+, the SETVERing also affects the version number
        WORD stored at offset +40h in each program's PSP (see #01378).
        This holds true even for special sub-versions of 100..255
        (see INT 21/AX=4452h).
      generic MS-DOS 3.30, Compaq MS-DOS 3.31, and others identify themselves
        as PC-DOS by returning OEM number 00h
      the version returned under DOS 4.0x may be modified by entries in
        the special program list (see #01662 at AH=52h); the version returned
        under DOS 5+ may be modified by SETVER--use AX=3306h to get the true
        version number

(Table 01394) Values for DOS OEM number: 00h * IBM

  1. (Novell DOS, Caldera OpenDOS, DR-OpenDOS, and DR-DOS 7.02+ report IBM

as their OEM) 01h * Compaq 02h * MS Packaged Product 04h * AT&T 05h * ZDS (Zenith Electronics, Zenith Electronics)

      Note:   Zenith DOS 3.30 supports >32MB hard disks; this OEM ID can be
                used to detect that support

06h * Hewlett-Packard 07h * Zenith Data Systems (ZDS, Groupe Bull), for DOS 5.0+ 08h * Tandon 09h * AST (AST Europe Ltd.) 0Ah * Asem 0Bh * Hantarex 0Ch * SystemsLine 0Dh * Packard-Bell 0Eh * Intercomp 0Fh * Unibit 10h * Unidata 16h * DEC 17h * Olivetti DOS 23h * Olivetti (may have been a typo, since 23 = 17h) 28h * Texas Instruments 29h * Toshiba 33h - Novell (Windows/386 device IDs only) 34h * MS Multimedia Systems (Windows/386 device IDs only) 35h * MS Multimedia Systems (Windows/386 device IDs only) 4Dh * Hewlett-Packard (HP) 5Eh - RxDOS (Api Software & Mike Podanoffsky) http://www.freedos.org/ 66h - PhysTechSoft (PTS-DOS) http://www.phystechsoft.com/

      probably Paragon Technology Systems Corporation PTS-DOS as well

99h - General Software's Embedded DOS CDh - Paragon Technology Systems Corporation (“Source DOS” S/DOS 1.0+)

      (see also INT 21/AH=20h"S/DOS")

EDh - reserved for future OpenDOS/DR-DOS based projects http://www.drdos.org EEh DR DOS EFh Novell DOS

      Note:   released versions of Novell DOS 7 use OEM ID 00h instead

FDh FreeDOS http://www.freedos.org/ FFh * Microsoft, Phoenix (listed as “undefined” by Microsoft) Notes: '*' indicates an OEM release of MS-DOS, while '-' indicates an OEM

        number used by a non-Microsoft DOS
      known OEM releases of MS-DOS:
          AT&T DOS 3.10 (uses DOS 2.x cluster sizes and FAT structures)
          Commodore DOS 3
          Compaq DOS 3.31 (>32MB partitions similar to MS-DOS 4+)
          Computerland DOS 3.10 (mix of DOS 2.x and 3.x disk mechanisms)
          Eagle MS-DOS 1.25 (DOS 1.x with some hard disk support and built-in
                ANSI.SYS functionality)
          Epson Equity III DOS 3.10 (different clustering)
          Leading Edge
          NEC DOS 3.3
          Olivetti DOS 2.11
          Phoenix DOS 3.3, 4.01
          Sanyo DOS 3.2
          Toshiba DOS
          Wyse MS-DOS 3
          Zenith DOS 2.x (uses Zenith disk mechanism, extra drives at G:)
          Zenith DOS 3.x (can be configured for Zenith or MS-DOS mechanism)
          Zenith DOS 3.3 PLUS (>32MB partitions similar to MS-DOS 4+)

See also

AX=3000h/BX=3000h,AX=3306h,AX=4452h,AH=87h,INT 15/AX=4900h AH=20h“S/DOS”,INT 2F/AX=122Fh,INT 2F/AX=4010h,INT 2F/AX=4A33h INT 2F/AX=E002h


Process manager INT 20H, INT 21H: 00H, 25H, 26H, 31H, 34H, 35H, 4CH, INT 22H, INT 27H, INT 28H
File manager INT 25H, INT 26H, INT 21H: 0DH, 0EH, 0FH, 10H, 11H, 12H, 13H, 14H, 15H, 16H, 17H, 19H, 1AH, 1BH, 1CH, 21H, 22H, 23H, 24H, 27H, 28H, 29H, 2EH, 2FH, 32H, 3305H, 36H, 39H, 3AH, 3BH
Character Device I/O INT 29H, INT 21H: 01H, 02H, 03H, 04H, 05H, 06H, 07H, 08H, 09H, 0AH, 0BH, 0AH, 0CH
Signals INT 23H, INT 24H, INT 21H: 3300H, 3301H, 3302H
Memory manager
Date and Time INT 21H: 2AH, 2BH, 2CH, 2DH
Misc INT 21H: 30H, 3306H, 3700H, 3701H, 3702H, 3703H
NLS INT 21H: 3303H, 3304H, 3800H, 3801H
2018/09/04 19:23 · prokushev

en/docs/dos/api/int21/30.txt · Last modified: 2020/12/09 05:17 by prokushev