This article details versions of MS-DOS, IBM PC DOS, and at least partially compatible disk operating systems. It does not include the many other operating systems called "DOS" which are unrelated to IBM PC compatibles.

Historical and licensing information

Originally MS-DOS was designed to be an operating system that could run on any computer with a 8086-family microprocessor. It competed with other operating systems written for such computers, such as CP/M-86 and UCSD Pascal. Each computer would have its own distinct hardware and its own version of MS-DOS, a situation similar to the one that existed for CP/M, with MS-DOS emulating the same solution as CP/M to adapt for different hardware platforms. So there were many different original equipment manufacturer (OEM) versions of MS-DOS for different hardware. But the greater speed attainable by direct control of hardware was of particular importance, especially when running computer games. So very soon an IBM-compatible architecture became the goal, and before long all 8086-family computers closely emulated IBM hardware, and only a single version of MS-DOS for a fixed hardware platform was all that was needed for the market. This specific version of MS-DOS is the version that is discussed here, as all other versions of MS-DOS died out with their respective systems. One version of such a generic MS-DOS (Z-DOS) is mentioned here, but there were dozens more. All these were for personal computers that used an 8086-family microprocessor, but which were not fully IBM PC compatible.

Name First public release date Creator Owner or maintainer as of 2021 License
86-DOS 0.42 1981-02-25 Seattle Computer Products Support ended Proprietary
86-DOS 1.00 1981-04-28
PC DOS 1.0 1981-08-12 Microsoft (for IBM)
PC DOS 1.1 1982-05-??
PC DOS 2.0 1983-03-??
PC DOS 2.1 1983-10-??
PC DOS 3.0 1984-08-??
PC DOS 3.1 1985
PC DOS 3.2 1986
PC DOS 3.3 1987
IBM DOS 4.0
(called PC DOS 4.0) 		1988
IBM DOS 5.0
(called PC DOS 5.0) 		1991
PC DOS 6.1, PC DOS 6.3 1993
PC DOS 7.0 (revision 0) 1995
PC DOS 2000
(PC DOS 7.0 revision 1) 		1998
PC DOS 7.10 2003 Support ended by IBM
MS-DOS 1.25[1] (first version named "MS-DOS") 1982 Microsoft Support ended Open source, MIT License
Z-DOS 1.25 1982-05-?? OEM Zenith Data Systems Proprietary
MS-DOS 2.0 1983-03-?? Microsoft Open source, MIT License
MS-DOS 2.11 1983-12-?? Proprietary
MS-DOS 3.0 1984
MS-DOS 3.1
MS-DOS 3.2 1986
MS-DOS 3.3 1987
MS-DOS 4.0 1988
MS-DOS 5.0 1991
MS-DOS 6.0 1993
MS-DOS 6.20
MS-DOS 6.21 March 1994  [2]
MS-DOS 6.22 April 1994  [2]
MS-DOS 7.0 (Windows 95A) 1995
MS-DOS 7.10 (Windows 95 OSRs 2 and 2.5, 98, 98 SE) 1996
MS-DOS 8.0 (Windows ME and later)[3] 2000 Support ended by Microsoft[4]
DOS Plus 1.1, 1.2/1.2a 1985 Digital Research Support ended
DOS Plus 2.1 1986
DR DOS 3.31-3.35 1988
DR DOS 3.40-3.41 1989
DR DOS 5.0 1990
DR DOS 6.0 1991
Novell DOS 7 1993 Novell
Caldera OpenDOS 7.01 1997 Caldera, Inc.;
Caldera UK, Ltd. 		Support ended officially;
a derivative, Enhanced DR-DOS, was
maintained by Udo Kuhnt until 2011 		Partial, free non-commercial use
Caldera DR-OpenDOS 7.02 Support ended
Caldera DR-DOS 7.02 1998 Proprietary
Caldera DR-DOS 7.03 1999, 1998 prereleased Caldera Thin Clients, Inc.;
Caldera UK, Ltd;
Lineo, Inc. 		DRDOS, Inc.
DR-DOS 8.0 2004 DeviceLogics Support ended
DR-DOS 8.1[5] 2005 DRDOS, Inc.
FreeDOS 1.0 2006-09-03 Jim Hall, et al. The FreeDOS Project Open source, GPL
FreeDOS 1.1 2012-01-02
FreeDOS 1.2 2016-12-25
FreeDOS 1.3 2021-12-14
PTS-DOS 6.4 1993 PhysTechSoft[6] PhysTechSoft Proprietary
PTS-DOS 6.5 ?
PTS-DOS 6.6
PTS-DOS 2000 (6.7)
PTS-DOS 32 (7.0)
PTS-DOS 6.51 ca. 1995 Paragon Technology Systems Paragon Technology Systems
Paragon DOS 2000 Pro ?
ROM-DOS 6.22[7] Datalight Datalight
ROM-DOS 7.1[7]
Embedded DOS General Software General Software
DIP DOS 2.11 1989 DIP Research, Atari Corporation Support ended
RxDOS 6.2 1999 Michael Podanoffsky Support ended Open source, GPL
RxDOS 7.20-7.24 2018 C. Masloch C. Masloch
SISNE plus ? Itautec, Scopus Tecnologia Support ended Proprietary

Technical specifications

Name Hard drive: partition size max Native support:
File systems 		Native support:
floppy capacities 3.5" 		Native support:
floppy capacities 5.25" 		Native support:
floppy capacities 8.0" 		Integrated disk compression utility Native support:
long file names
86-DOS 0.42-1.00 — FAT12;
(CP/M 2 through RDCPM) 		— NorthStar 87.5 KB; Cromemco 90 KB Cromemco/Tarbell 250.25 KB; Tarbell 616 KB; Tarbell 1232 KB[8] No No
MS-DOS 1.25 — FAT12 — 160 KB; 320 KB 250.25 KB[9] No No
MS-DOS 2.0-2.11 16 MB (32 MB with third-party FORMAT)[10] FAT12 — 160 KB; 180 KB; 320 KB; 360 KB 250.25 KB;[9][11][12] 500.5 KB;[9][11][12] 616 KB;[11][12] 1232 KB[9][11][12] No No
MS-DOS 3.0 32 MB FAT12, FAT16 — 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB — No No
MS-DOS 3.1 32 MB FAT12, FAT16 — 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB — No No
MS-DOS 3.2 32 MB FAT12, FAT16 720 KB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB — No No
MS-DOS 3.3 32 MB FAT12, FAT16 720 KB; 1.44 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB — No No
MS-DOS 3.31 512 MB FAT12, FAT16, FAT16B 720 KB; 1.44 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB — No No
MS-DOS 4.0 2 GB FAT12, FAT16, FAT16B 720 KB; 1.44 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB — No No
MS-DOS 5.0 2 GB FAT12, FAT16, FAT16B 720 KB, 1.44 MB, 2.88 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB — No No
MS-DOS 6.0 2 GB FAT12, FAT16, FAT16B 720 KB; 1.44 MB, 2.88 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB — DoubleSpace No
MS-DOS 6.20 2 GB FAT12, FAT16, FAT16B 720 KB; 1.44 MB, 2.88 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB — DoubleSpace No
MS-DOS 6.21 2 GB FAT12, FAT16, FAT16B 720 KB; 1.44 MB, 2.88 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB — No No
MS-DOS 6.22 2 GB FAT12, FAT16, FAT16B 720 KB; 1.44 MB, 2.88 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB — DriveSpace No
MS-DOS 7.0 (Windows 95A) 2 GB FAT12, FAT16, FAT16B 720 KB; 1.44 MB, 2.88 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB — DriveSpace No
MS-DOS 7.1 (Windows 95B/OSR2, Windows 95C/OSR2.5, Windows 98, and Windows 98SE) 124.55 GB with FAT32[13] FAT12, FAT16, FAT16B, FAT32 720 KB; 1.44 MB, 2.88 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB — DriveSpace for Windows 95, none for Windows 98 No
MS-DOS 8.0 (Windows Me and later Windows versions)[3] 124.55 GB with FAT32[13] FAT12, FAT16, FAT16B, FAT32 720 KB; 1.44 MB, 2.88 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB — No No
PC DOS 1.0 — FAT12 — 160 KB — No No
PC DOS 1.1 — FAT12 — 160 KB; 320 KB (double-sided) — No No
PC DOS 2.0-2.1 16 MB (32 MB with third-party FORMAT)[10] FAT12 — 160 KB; 180 KB; 320 KB; 360 KB — No No
PC DOS 3.0 32 MB FAT12, FAT16 — 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB — No No
PC DOS 3.1 32 MB FAT12, FAT16 — 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB — No No
PC DOS 3.2 32 MB FAT12, FAT16 720 KB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB — No No
PC DOS 3.3 32 MB FAT12, FAT16 720 KB; 1.44 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB — No No
IBM DOS 4.0 2 GB FAT12, FAT16, FAT16B 720 KB; 1.44 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB — No No
IBM DOS 5.0 2 GB FAT12, FAT16, FAT16B 720 KB, 1.44 MB, 2.88 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB — No No
PC DOS 6.1 (early version) 2 GB FAT12, FAT16, FAT16B 720 KB; 1.44 MB, 2.88 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB — No No
PC DOS 6.1 with Compression / PC DOS 6.3 2 GB FAT12, FAT16, FAT16B 720 KB; 1.44 MB, 2.88 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB — SuperStor No
PC DOS 7.0 / PC DOS 2000 2 GB FAT12, FAT16, FAT16B 720 KB; 1.44 MB, 1.86 MB (XDF), 2.88 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB, 1.54 MB (XDF) — Stacker No
PC DOS 7.10 ? FAT12, FAT16, FAT16B, FAT32 720 KB; 1.44 MB, 1.86 MB (XDF), 2.88 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB, 1.54 MB (XDF) — Stacker, not on FAT32 No
DOS Plus 1.1 32 MB FAT12, FAT16, CP/M-86 315 KB; 720 KB; CP/M 315 KB; CP/M 720 KB; MSX-DOS 360 KB; MSX-DOS 720 KB 160 KB; 180 KB; 320 KB; 360 KB; 800 KB; 1.2 MB; CP/M 160 KB; CP/M 320 KB — No No
DOS Plus 1.2-2.1 32 MB FAT12, FAT16, CP/M-86 Apricot 315 KB;[14] (720 KB[15]) 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB; Acorn 640 KB; Acorn 800 KB;[16] CP/M 320 KB — No No
DR DOS 3.31-3.35 2 GB[citation needed] FAT12, FAT16, FAT16B 720 KB; 1.44 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB — No No
DR DOS 3.40-3.41 2 GB FAT12, FAT16, FAT16B 720 KB; 1.44 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB (250.25 KB[17]) No No
DR DOS 5.0 2 GB FAT12, FAT16, FAT16B 720 KB; 1.44 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB (250.25 KB[17]) No No
DR DOS 6.0 2 GB FAT12, FAT16, FAT16B 720 KB; 1.44 MB, 2.88 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB (250.25 KB[17]) SuperStor No
PalmDOS 1.0 2 GB FAT12, FAT16, FAT16B 720 KB; 1.44 MB, 2.88 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB (250.25 KB[17]) SuperStor No
Novell DOS 7 2 GB FAT12, FAT16, FAT16B 720 KB; 1.44 MB, 2.88 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB (250.25 KB[17]) Stacker No
OpenDOS 7.01 2 GB FAT12, FAT16, FAT16B 720 KB; 1.44 MB, 2.88 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB (250.25 KB[17]) Stacker No
DR-OpenDOS 7.02 2 GB FAT12, FAT16, FAT16B 720 KB; 1.44 MB, 2.88 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB (250.25 KB[17]) Stacker No
DR-DOS 7.02 2 GB FAT12, FAT16, FAT16B, (FAT32 in FDISK only) 720 KB; 1.44 MB, 2.88 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB (250.25 KB[17]) Stacker Partial, COMMAND.COM and LONGNAME only
DR-DOS 7.03 2 GB FAT12, FAT16, FAT16B, (FAT32 in FDISK only) 720 KB; 1.44 MB, 2.88 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB (250.25 KB[17]) Stacker Partial, COMMAND.COM and LONGNAME only
DR-DOS 7.04-7.05 ? FAT12, FAT16, FAT16B, FAT32 (non-bootable) 720 KB; 1.44 MB, 2.88 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB (250.25 KB[17]) Stacker, not on FAT32 Partial, COMMAND.COM and LONGNAME only
DR-DOS 7.06-7.07 ? FAT12, FAT16, FAT16B, FAT32 (bootable) 720 KB; 1.44 MB, 2.88 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB (250.25 KB[17]) Stacker, not on FAT32 Partial, COMMAND.COM and LONGNAME only
DR-DOS 8.0 ? FAT12, FAT16, FAT16B, FAT32 720 KB; 1.44 MB, 2.88 MB 160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB (250.25 KB[17]) Supported, not on FAT32 Partial, COMMAND.COM only
DR-DOS 8.1 ? FAT12, FAT16, FAT16B, FAT32 720 KB; 1.44 MB, 2.88 MB 360 KB; 1.2 MB — No No
FreeDOS 1.0 2 TB[citation needed] FAT12, FAT16, FAT16B, FAT32 720 KB; 1.44 MB, 2.88 MB 360 KB; 1.2 MB — ? No
FreeDOS 1.1-1.3 2 TB[citation needed] FAT12, FAT16, FAT16B, FAT32 720 KB; 1.44 MB, 2.88 MB 360 KB; 1.2 MB — No Yes
PTS-DOS 32 ? FAT12, FAT16, FAT16B, FAT32 720 KB; 1.44 MB, 2.88 MB 360 KB; 1.2 MB — No No
PTS-DOS 2000 ? FAT12, FAT16, FAT16B, FAT32 720 KB; 1.44 MB, 2.88 MB 360 KB; 1.2 MB — No No
PTS-DOS 2000 PRO ? FAT12, FAT16, FAT16B, FAT32 720 KB; 1.44 MB, 2.88 MB 360 KB; 1.2 MB — No No
Datalight ROM-DOS ? FAT12, FAT16, FAT16B, FAT32 720 KB; 1.44 MB, 2.88 MB 360 KB; 1.2 MB — No Yes
DIP DOS — FAT12 — — — No No

See also

References

  1. ^ Conner, Doug. "Father of DOS Still Having Fun at Microsoft". Micronews. Archived from the original on 9 February 2010.
  2. ^ a b "Microsoft DOS history". ComputerHope.
  3. ^ a b MS-DOS 8.0 has most of the functionality of prior versions, but with significant losses of usability, e.g., the loss of FORMAT /S command, that can be substituted by formatting HDD/FDD and then copying IO.SYS from CD-ROM boot A: image, as first ever file onto drive; loss of SYS A: (or SYS B:) command for floppies, that can be substituted too in the same way as FORMAT /S; inability to boot to a command prompt without substitution/modification of IO.SYS (other than CD-ROM boot version) and COMMAND.COM. For purpose of booting from C: drive, an unmodified IO.SYS from simulated A: boot diskette image, that is placed on Windows Me OEM CD-ROM, from which that CD boots, can be used, and English COMMAND.COM can be modified by replacing in this file at hex offset 00006510h byte 75h by byte EBh, or substituted by (now freeware) 4DOS http://www.jpsoft.com/download.htm Archived 2006-09-01 at the Wayback Machine
  4. ^ While Windows ME support ended, a version of its underlying DOS is included with Windows XP. When one formats a floppy in Windows XP and selects "Create an MS-DOS startup disk", the floppy is formatted with a DOS version that identifies itself as "Windows Millennium Version 4.90.3000".
  5. ^ DR-DOS 8.1 was pulled from the market after it was discovered that 8.1 code had been copied from FreeDOS in violation of the GPL license.
  6. ^ "Phystechsoft". Retrieved 2016-09-19. PTS-DOS 32 [..] Memory Manager himem.sys, included in PTS-DOS 32, supports up to 4 GB of RAM.
    PTS-DOS 2000 [..] PTS-DOS is a powerful and fast 16-bit disk operating system, fully compatible with MS-DOS and all its applications.
  7. ^ a b "ROM-DOS Single User Version". Retrieved 2016-09-19. 6.22 and 7.1 kernels
  8. ^ http://www.86dos.org/downloads/86DOS_FILES.ZIP Archived 24 July 2011 at the Wayback Machine, A ZIP file containing most of the files from 86-DOS 0.75 (1981-04-18) to 1.00 (1981-07-21)
  9. ^ a b c d "Standard Floppy Disk Formats Supported by MS-DOS". 2.0. Microsoft Help and Support. 2003-05-12. Retrieved 2012-09-11.
  10. ^ a b Scott Mueller (1995). Upgrading and Repairing PCs, 5th Edition. Que Corporation. ISBN 0-7897-0321-1. p784: "The limit of 16MB did not come from the FAT, but from the high-level DOS FORMAT command... Most vendors supplied modified high-level format programs that permitted partitions of up to 32MB to be formatted properly."
  11. ^ a b c d Zbikowski, Mark; Allen, Paul; Ballmer, Steve; Borman, Reuben; Borman, Rob; Butler, John; Carroll, Chuck; Chamberlain, Mark; Chell, David; Colee, Mike; Courtney, Mike; Dryfoos, Mike; Duncan, Rachel; Eckhardt, Kurt; Evans, Eric; Farmer, Rick; Gates, Bill; Geary, Michael; Griffin, Bob; Hogarth, Doug; Johnson, James W.; Kermaani, Kaamel; King, Adrian; Koch, Reed; Landowski, James; Larson, Chris; Lennon, Thomas; Lipkie, Dan; McDonald, Marc; McKinney, Bruce; Martin, Pascal; Mathers, Estelle; Matthews, Bob; Melin, David; Mergentime, Charles; Nevin, Randy; Newell, Dan; Newell, Tani; Norris, David; O'Leary, Mike; O'Rear, Bob; Olsson, Mike; Osterman, Larry; Ostling, Ridge; Pai, Sunil; Paterson, Tim; Perez, Gary; Peters, Chris; Petzold, Charles; Pollock, John; Reynolds, Aaron; Rubin, Darryl; Ryan, Ralph; Schulmeisters, Karl; Shah, Rajen; Shaw, Barry; Short, Anthony; Slivka, Ben; Smirl, Jon; Stillmaker, Betty; Stoddard, John; Tillman, Dennis; Whitten, Greg; Yount, Natalie; Zeck, Steve (1988). "Technical advisors". The MS-DOS Encyclopedia: versions 1.0 through 3.2. By Duncan, Ray; Bostwick, Steve; Burgoyne, Keith; Byers, Robert A.; Hogan, Thom; Kyle, Jim; Letwin, Gordon; Petzold, Charles; Rabinowitz, Chip; Tomlin, Jim; Wilton, Richard; Wolverton, Van; Wong, William; Woodcock, JoAnne (Completely reworked ed.). Redmond, Washington, USA: Microsoft Press. ISBN 1-55615-049-0. LCCN 87-21452. OCLC 16581341. (xix+1570 pages; 26 cm) (NB. This edition was published in 1988 after extensive rework of the withdrawn 1986 first edition by a different team of authors. [1])
  12. ^ a b c d Xerox (1983-11). Xerox 16/8 Professional Computer - MS-DOS OS Handbook for 8" Floppy Disks. 1983-11, MS-DOS 2.0 ([2])
  13. ^ a b As stated at http://support.microsoft.com/default.aspx?scid=KB;EN-US;Q184006& Microsoft's KB article 184006, the limit of 124.55 GB for FAT32 partition size is a mainly a limit of Windows 95/98's 16-bit SCANDISK utility. Other DOS versions supporting FAT32 may allow a larger partition size closer to the theoretical 2 TB/16 TB maximum suggested by FAT32's specifications. Windows 2000 and XP can mount and use a FAT32 partition larger than 32 GB, but they cannot natively create one, which according to Microsoft is by design.
  14. ^ DOS Plus 2.1e/g versions for the Apricot ACT series and for the Jasmin Turbo from the French company T.R.A.N. S.A. support a non-standard single-sided 315 KB FAT12 format.
  15. ^ DOS Plus DISK.CMD versions for the Amstrad PC1512, the T.R.A.N. Jasmin Turbo and the BBC Master 512 support variants of 720 KB FAT12 formats including the original MS-DOS, and PC DOS format, however known versions of DOS Plus itself don't make use of them.
  16. ^ DOS Plus for the BBC Master 512 supports two non-standard FAT12 formats with 640 KB and 800 KB.
  17. ^ a b c d e f g h i j k l The DR DOS 3.41-8.0 BIOS (DRBIOS.SYS aka IBMBIO.COM) has a profile for an undocumented 250.25 KB (aka "243 KB") logical format with a non-standard media descriptor of E5h. DR DOS 3.31 does not support this format. The format is similar, but not identical to the two 250.25 KB formats with FAT IDs FDh and FEh supported by MS-DOS 1.25/2.x.

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