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.

NameFirst public release dateCreatorOwner or maintainer as of 2021[update]License
86-DOS 0.42February 25, 1981Seattle Computer ProductsSupport endedProprietary
86-DOS 1.00April 28, 1981
PC DOS 1.0August 12, 1981Microsoft (for IBM)
PC DOS 1.1May 1982
PC DOS 2.0March 1983
PC DOS 2.1October 1983
PC DOS 3.0August 1984
PC DOS 3.11985
PC DOS 3.21986
PC DOS 3.31987
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 6.31993IBM
PC DOS 7.0 (revision 0)1995
PC DOS 2000 (PC DOS 7.0 revision 1)1998
PC DOS 7.102003Support ended by IBM
MS-DOS 1.25 (first version named "MS-DOS")1982MicrosoftSupport endedOpen source, MIT License
Z-DOS 1.25May 1982OEM Zenith Data SystemsProprietary
MS-DOS 2.0March 1983MicrosoftOpen source, MIT License
MS-DOS 2.11December 1983Proprietary
MS-DOS 3.01984
MS-DOS 3.1
MS-DOS 3.21986
MS-DOS 3.31987
MS-DOS 4.01988Open source, MIT License
MS-DOS 5.01991Proprietary
MS-DOS 6.01993
MS-DOS 6.20
MS-DOS 6.21March 1994
MS-DOS 6.22April 1994
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)2000Support ended by Microsoft
DOS Plus 1.1, 1.2/1.2a1985Digital ResearchSupport ended
DOS Plus 2.11986
DR DOS 3.31-3.351988
DR DOS 3.40-3.411989
DR DOS 5.01990
DR DOS 6.01991
Novell DOS 71993Novell
Caldera OpenDOS 7.011997Caldera, Inc.; Caldera UK, Ltd.Support ended officially; a derivative, Enhanced DR-DOS, was maintained by Udo Kuhnt until 2011Partial, free non-commercial use
Caldera DR-OpenDOS 7.02Support ended
Caldera DR-DOS 7.021998Proprietary
Caldera DR-DOS 7.031999, 1998 prereleasedCaldera Thin Clients, Inc.; Caldera UK, Ltd; Lineo, Inc.DRDOS, Inc.
DR-DOS 8.02004DeviceLogicsSupport ended
DR-DOS 8.12005DRDOS, Inc.
FreeDOS 1.0September 3, 2006Jim Hall, et al.The FreeDOS ProjectOpen source, GPL
FreeDOS 1.1January 2, 2012
FreeDOS 1.2December 25, 2016
FreeDOS 1.3December 14, 2021
PTS-DOS 6.41993PhysTechSoftPhysTechSoftProprietary
PTS-DOS 6.5?
PTS-DOS 6.6
PTS-DOS 2000 (6.7)
PTS-DOS 32 (7.0)
PTS-DOS 6.51ca. 1995Paragon Technology SystemsParagon Technology Systems
Paragon DOS 2000 Pro?
ROM-DOS 6.22DatalightDatalight
ROM-DOS 7.1
Embedded DOSGeneral SoftwareGeneral Software
DIP DOS 2.111989DIP Research, Atari CorporationSupport ended
RxDOS 6.21999Michael PodanoffskySupport endedOpen source, GPL
RxDOS 7.20-7.242018C. MaslochC. Masloch
SISNE plus?Itautec, Scopus TecnologiaSupport endedProprietary

Technical specifications

NameHard drive: partition size maxNative support: File systemsNative support: floppy capacities 3.5"Native support: floppy capacities 5.25"Native support: floppy capacities 8.0"Integrated disk compression utilityNative support: long file names
86-DOS 0.42-1.00—N/aFAT12; (CP/M 2 through RDCPM)—N/aNorthStar 87.5 KB; Cromemco 90 KBCromemco/Tarbell 250.25 KB; Tarbell 616 KB; Tarbell 1232 KBNoNo
MS-DOS 1.25—N/aFAT12—N/a160 KB; 320 KB250.25 KBNoNo
MS-DOS 2.0-2.1116 MB (32 MB with third-party FORMAT)FAT12—N/a160 KB; 180 KB; 320 KB; 360 KB250.25 KB; 500.5 KB; 616 KB; 1232 KBNoNo
MS-DOS 3.032 MBFAT12, FAT16—N/a160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB—N/aNoNo
MS-DOS 3.132 MBFAT12, FAT16—N/a160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB—N/aNoNo
MS-DOS 3.232 MBFAT12, FAT16720 KB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB—N/aNoNo
MS-DOS 3.332 MBFAT12, FAT16720 KB; 1.44 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB—N/aNoNo
MS-DOS 3.31512 MBFAT12, FAT16, FAT16B720 KB; 1.44 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB—N/aNoNo
MS-DOS 4.02 GBFAT12, FAT16, FAT16B720 KB; 1.44 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB—N/aNoNo
MS-DOS 5.02 GBFAT12, FAT16, FAT16B720 KB, 1.44 MB, 2.88 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB—N/aNoNo
MS-DOS 6.02 GBFAT12, FAT16, FAT16B720 KB; 1.44 MB, 2.88 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB—N/aDoubleSpaceNo
MS-DOS 6.202 GBFAT12, FAT16, FAT16B720 KB; 1.44 MB, 2.88 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB—N/aDoubleSpaceNo
MS-DOS 6.212 GBFAT12, FAT16, FAT16B720 KB; 1.44 MB, 2.88 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB—N/aNoNo
MS-DOS 6.222 GBFAT12, FAT16, FAT16B720 KB; 1.44 MB, 2.88 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB—N/aDriveSpaceNo
MS-DOS 7.0 (Windows 95A)2 GBFAT12, FAT16, FAT16B720 KB; 1.44 MB, 2.88 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB—N/aDriveSpaceNo
MS-DOS 7.1 (Windows 95B/OSR2, Windows 95C/OSR2.5, Windows 98, and Windows 98SE)124.55 GB with FAT32FAT12, FAT16, FAT16B, FAT32720 KB; 1.44 MB, 2.88 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB—N/aDriveSpace for Windows 95, none for Windows 98No
MS-DOS 8.0 (Windows Me and later Windows versions)124.55 GB with FAT32FAT12, FAT16, FAT16B, FAT32720 KB; 1.44 MB, 2.88 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB—N/aNoNo
PC DOS 1.0—N/aFAT12—N/a160 KB—N/aNoNo
PC DOS 1.1—N/aFAT12—N/a160 KB; 320 KB (double-sided)—N/aNoNo
PC DOS 2.0-2.116 MB (32 MB with third-party FORMAT)FAT12—N/a160 KB; 180 KB; 320 KB; 360 KB—N/aNoNo
PC DOS 3.032 MBFAT12, FAT16—N/a160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB—N/aNoNo
PC DOS 3.132 MBFAT12, FAT16—N/a160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB—N/aNoNo
PC DOS 3.232 MBFAT12, FAT16720 KB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB—N/aNoNo
PC DOS 3.332 MBFAT12, FAT16720 KB; 1.44 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB—N/aNoNo
IBM DOS 4.02 GBFAT12, FAT16, FAT16B720 KB; 1.44 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB—N/aNoNo
IBM DOS 5.02 GBFAT12, FAT16, FAT16B720 KB, 1.44 MB, 2.88 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB—N/aNoNo
PC DOS 6.1 (early version)2 GBFAT12, FAT16, FAT16B720 KB; 1.44 MB, 2.88 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB—N/aNoNo
PC DOS 6.1 with Compression / PC DOS 6.32 GBFAT12, FAT16, FAT16B720 KB; 1.44 MB, 2.88 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB—N/aSuperStorNo
PC DOS 7.0 / PC DOS 20002 GBFAT12, FAT16, FAT16B720 KB; 1.44 MB, 1.86 MB (XDF), 2.88 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB, 1.54 MB (XDF)—N/aStackerNo
PC DOS 7.10?FAT12, FAT16, FAT16B, FAT32720 KB; 1.44 MB, 1.86 MB (XDF), 2.88 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB, 1.54 MB (XDF)—N/aStacker, not on FAT32No
DOS Plus 1.132 MBFAT12, FAT16, CP/M-86315 KB; 720 KB; CP/M 315 KB; CP/M 720 KB; MSX-DOS 360 KB; MSX-DOS 720 KB160 KB; 180 KB; 320 KB; 360 KB; 800 KB; 1.2 MB; CP/M 160 KB; CP/M 320 KB—N/aNoNo
DOS Plus 1.2-2.132 MBFAT12, FAT16, CP/M-86Apricot 315 KB; (720 KB)160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB; Acorn 640 KB; Acorn 800 KB; CP/M 320 KB—N/aNoNo
DR DOS 3.31-3.352 GB[citation needed]FAT12, FAT16, FAT16B720 KB; 1.44 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB—N/aNoNo
DR DOS 3.40-3.412 GBFAT12, FAT16, FAT16B720 KB; 1.44 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB(250.25 KB)NoNo
DR DOS 5.02 GBFAT12, FAT16, FAT16B720 KB; 1.44 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB(250.25 KB)NoNo
DR DOS 6.02 GBFAT12, FAT16, FAT16B720 KB; 1.44 MB, 2.88 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB(250.25 KB)SuperStorNo
PalmDOS 1.02 GBFAT12, FAT16, FAT16B720 KB; 1.44 MB, 2.88 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB(250.25 KB)SuperStorNo
Novell DOS 72 GBFAT12, FAT16, FAT16B720 KB; 1.44 MB, 2.88 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB(250.25 KB)StackerNo
OpenDOS 7.012 GBFAT12, FAT16, FAT16B720 KB; 1.44 MB, 2.88 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB(250.25 KB)StackerNo
DR-OpenDOS 7.022 GBFAT12, FAT16, FAT16B720 KB; 1.44 MB, 2.88 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB(250.25 KB)StackerNo
DR-DOS 7.022 GBFAT12, FAT16, FAT16B, (FAT32 in FDISK only)720 KB; 1.44 MB, 2.88 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB(250.25 KB)StackerPartial, COMMAND.COM and LONGNAME only
DR-DOS 7.032 GBFAT12, FAT16, FAT16B, (FAT32 in FDISK only)720 KB; 1.44 MB, 2.88 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB(250.25 KB)StackerPartial, COMMAND.COM and LONGNAME only
DR-DOS 7.04-7.05?FAT12, FAT16, FAT16B, FAT32 (non-bootable)720 KB; 1.44 MB, 2.88 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB(250.25 KB)Stacker, not on FAT32Partial, COMMAND.COM and LONGNAME only
DR-DOS 7.06-7.07?FAT12, FAT16, FAT16B, FAT32 (bootable)720 KB; 1.44 MB, 2.88 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB(250.25 KB)Stacker, not on FAT32Partial, COMMAND.COM and LONGNAME only
DR-DOS 8.0?FAT12, FAT16, FAT16B, FAT32720 KB; 1.44 MB, 2.88 MB160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB(250.25 KB)Supported, not on FAT32Partial, COMMAND.COM only
DR-DOS 8.1?FAT12, FAT16, FAT16B, FAT32720 KB; 1.44 MB, 2.88 MB360 KB; 1.2 MB—N/aNoNo
FreeDOS 1.02 TB [citation needed]FAT12, FAT16, FAT16B, FAT32720 KB; 1.44 MB, 2.88 MB360 KB; 1.2 MB—N/a?No
FreeDOS 1.1-1.32 TB [citation needed]FAT12, FAT16, FAT16B, FAT32720 KB; 1.44 MB, 2.88 MB360 KB; 1.2 MB—N/aNoYes
PTS-DOS 32?FAT12, FAT16, FAT16B, FAT32720 KB; 1.44 MB, 2.88 MB360 KB; 1.2 MB—N/aNoNo
PTS-DOS 2000?FAT12, FAT16, FAT16B, FAT32720 KB; 1.44 MB, 2.88 MB360 KB; 1.2 MB—N/aNoNo
PTS-DOS 2000 PRO?FAT12, FAT16, FAT16B, FAT32720 KB; 1.44 MB, 2.88 MB360 KB; 1.2 MB—N/aNoNo
Datalight ROM-DOS?FAT12, FAT16, FAT16B, FAT32720 KB; 1.44 MB, 2.88 MB360 KB; 1.2 MB—N/aNoYes
DIP DOS—N/aFAT12—N/a—N/a—N/aNoNo

See also

External links