Comparison of DOS operating systems

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.

COMPAQ-DOS

While developing the Compaq Portable in early 1982, engineers discovered that MS-DOS and PC DOS are not identical, causing some compatibility issues. Microsoft's Bill Gates explained to Compaq's Rod Canion that the former's license agreement with IBM required Microsoft to use separate teams of developers, causing the code bases to diverge. While Microsoft could not sell PC DOS to Compaq, it could disclose to the latter the last version of DOS before the two operating systems diverged. Compaq licensed that version and used it to develop COMPAQ-DOS, slightly more compatible with PC DOS than MS-DOS. After customers began buying COMPAQ-DOS for use with other clones, Compaq stopped standalone sales and secretly licensed the operating system back to Microsoft. Microsoft discontinued its own development of MS-DOS and resold Compaq's software. By having Microsoft resell new versions of COMPAQ-DOS as MS-DOS a few months after Compaq released them, Compaq remained always slightly more compatible with the IBM PC than other clone makers.^[1]

Name	First public release date	Creator	Owner or maintainer as of 2021[update]	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[2] (first version named "MS-DOS")	1982	Microsoft	Support ended	Open source, MIT License[3]
Z-DOS 1.25	1982-05-??	OEM Zenith Data Systems		Proprietary
MS-DOS 2.0	1983-03-??	Microsoft		Open source, MIT License[3]
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			Open source, MIT License[3]
MS-DOS 5.0	1991			Proprietary
MS-DOS 6.0	1993
MS-DOS 6.20
MS-DOS 6.21	March 1994[4]
MS-DOS 6.22	April 1994[4]
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)[5]	2000		Support ended by Microsoft[6]
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[7]	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[8]	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[9]		Datalight	Datalight
ROM-DOS 7.1[9]
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[10]	No	No
MS-DOS 1.25	—	FAT12	—	160 KB; 320 KB	250.25 KB[11]	No	No
MS-DOS 2.0-2.11	16 MB (32 MB with third-party FORMAT)[12]	FAT12	—	160 KB; 180 KB; 320 KB; 360 KB	250.25 KB;[11][13][14] 500.5 KB;[11][13][14] 616 KB;[13][14] 1232 KB[11][13][14]	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[15]	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)[5]	124.55 GB with FAT32[15]	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)[12]	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;[16] (720 KB[17])	160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB; Acorn 640 KB; Acorn 800 KB;[18] 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[19])	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[19])	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[19])	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[19])	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[19])	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[19])	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[19])	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[19])	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[19])	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[19])	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[19])	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[19])	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

• Timeline of DOS operating systems
• OS/2
• List of operating systems
• Comparison of Linux distributions
• Comparison of operating systems