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2130

Category: DOS kernel

INT 21 - DOS 2+ - GET DOS VERSION

	AH = 30h
---DOS 5+ ---
	AL = what to return in BH
	    00h OEM number (see #01394)
	    01h version flag
Return: 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
	  v20.40.
	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
	  versions:
	  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
SeeAlso: AX=3000h/BX=3000h,AX=3306h,AX=4452h,AH=87h,INT 15/AX=4900h
SeeAlso: AH=20h"S/DOS",INT 2F/AX=122Fh,INT 2F/AX=4010h,INT 2F/AX=4A33h
SeeAlso: INT 2F/AX=E002h


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