Comparison of DOS operating systems explained

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	License
	86-DOS 0.42	1981-02-25	Seattle Computer Products	rowspan="16"
	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
	MS-DOS 1.25^[1] (first version named "MS-DOS")	1982	Microsoft	, MIT License^[2]
	Z-DOS 1.25	1982-05-??	OEM Zenith Data Systems
	MS-DOS 2.0	1983-03-??	Microsoft		, MIT License
	MS-DOS 2.11	1983-12-??			rowspan="5"
	MS-DOS 3.0	1984
	MS-DOS 3.1
	MS-DOS 3.2	1986
	MS-DOS 3.3	1987
	MS-DOS 4.0	1988			, MIT License
	MS-DOS 5.0	1991			rowspan="15"
	MS-DOS 6.0	1993
	MS-DOS 6.20
	MS-DOS 6.21	March 1994
	MS-DOS 6.22	April 1994
	MS-DOS 7.0 (Windows 95A)	1995
	MS-DOS 7.10 (Windows, 98,)	1996
	MS-DOS 8.0 (Windows ME and later)^[3]	2000		^[4]
	DOS Plus 1.1, 1.2/1.2a	1985	Digital Research	rowspan="7"
	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.	officially; a derivative, Enhanced DR-DOS, was maintained by Udo Kuhnt until 2011	rowspan="2", free non-commercial use
	Caldera DR-OpenDOS 7.02			rowspan="2"
	Caldera DR-DOS 7.02	1998		rowspan="4"
	Caldera DR-DOS 7.03	1999, 1998 prereleased	Caldera Thin Clients, Inc.; Caldera UK, Ltd; Lineo, Inc.
	DR-DOS 8.0	2004	DeviceLogics	rowspan="2"
	DR-DOS 8.1^[5]	2005	DRDOS, Inc.
	FreeDOS 1.0	2006-09-03	Jim Hall, et al.	rowspan="4", 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]	rowspan="11"
	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	rowspan="2"
	Paragon DOS 2000 Pro	?
	ROM-DOS 6.22^[7]		Datalight	rowspan="2"
	ROM-DOS 7.1
	Embedded DOS		General Software
	DIP DOS 2.11	1989	DIP Research, Atari Corporation
	RxDOS 6.2	1999	Michael Podanoffsky		rowspan="2", GPL
	RxDOS 7.20-7.24	2018	C. Masloch
	SISNE plus	?	Itautec, Scopus Tecnologia

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<	-- DD/1S (WD1791) -->; Tarbell 1232 KB^[8]	-- date stamp of files -->) to 1.00 (1981-07-21)
	MS-DOS 1.25		FAT12		160 KB; 320 KB	250.25 KB^[9]
	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; 500.5 KB; 616 KB; 1232 KB^[11]
	MS-DOS 3.0	32 MB	FAT12, FAT16		160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB
	MS-DOS 3.1	32 MB	FAT12, FAT16		160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB
	MS-DOS 3.2	32 MB	FAT12, FAT16	720 KB	160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB
	MS-DOS 3.3	32 MB	FAT12, FAT16	720 KB; 1.44 MB	160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB
	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
	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
	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
	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
	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
	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
	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
	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
	MS-DOS 7.1 (Windows 95B/OSR2, Windows 95C/OSR2.5, Windows 98, and Windows 98SE)	124.55 GB with FAT32^[12]	FAT12, FAT16, FAT16B, FAT32	720 KB; 1.44 MB, 2.88 MB	160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB
	MS-DOS 8.0 (Windows Me and later Windows versions)	124.55 GB with FAT32	FAT12, FAT16, FAT16B, FAT32	720 KB; 1.44 MB, 2.88 MB	160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB
	PC DOS 1.0		FAT12		160 KB
	PC DOS 1.1		FAT12		160 KB; 320 KB (double-sided)
	PC DOS 2.0-2.1	16 MB (32 MB with third-party FORMAT)	FAT12		160 KB; 180 KB; 320 KB; 360 KB
	PC DOS 3.0	32 MB	FAT12, FAT16		160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB
	PC DOS 3.1	32 MB	FAT12, FAT16		160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB
	PC DOS 3.2	32 MB	FAT12, FAT16	720 KB	160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB
	PC DOS 3.3	32 MB	FAT12, FAT16	720 KB; 1.44 MB	160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB
	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
	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
	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
	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
	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)
	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)
	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
	DOS Plus 1.2-2.1	32 MB	FAT12, FAT16, CP/M-86	Apricot 315 KB;^[13] (720 KB^[14])	160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB; Acorn 640 KB; Acorn 800 KB;^[15] CP/M 320 KB
	DR DOS 3.31-3.35	2 GB	FAT12, FAT16, FAT16B	720 KB; 1.44 MB	160 KB; 180 KB; 320 KB; 360 KB; 1.2 MB
	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^[16])
	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)
	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)
	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)
	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)
	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)
	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)
	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)		, 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)		, 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)		, 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)		, 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)		, COMMAND.COM only
	DR-DOS 8.1		FAT12, FAT16, FAT16B, FAT32	720 KB; 1.44 MB, 2.88 MB	360 KB; 1.2 MB
	FreeDOS 1.0	2 TB	FAT12, FAT16, FAT16B, FAT32	720 KB; 1.44 MB, 2.88 MB	360 KB; 1.2 MB
	FreeDOS 1.1-1.3	2 TB	FAT12, FAT16, FAT16B, FAT32	720 KB; 1.44 MB, 2.88 MB	360 KB; 1.2 MB
	PTS-DOS 32		FAT12, FAT16, FAT16B, FAT32	720 KB; 1.44 MB, 2.88 MB	360 KB; 1.2 MB
	PTS-DOS 2000		FAT12, FAT16, FAT16B, FAT32	720 KB; 1.44 MB, 2.88 MB	360 KB; 1.2 MB
	PTS-DOS 2000 PRO		FAT12, FAT16, FAT16B, FAT32	720 KB; 1.44 MB, 2.88 MB	360 KB; 1.2 MB
	Datalight ROM-DOS		FAT12, FAT16, FAT16B, FAT32	720 KB; 1.44 MB, 2.88 MB	360 KB; 1.2 MB
	DIP DOS		FAT12

See also

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

External links

• Detailed timeline of DOS variants
• DR-DOS version dates

Notes and References

1. Web site: Father of DOS Still Having Fun at Microsoft . Conner . Doug . . dead . https://web.archive.org/web/20100209023553/http://www.patersontech.com/Dos/Micronews/paterson04_10_98.htm . 9 February 2010 . dmy-all .
2. Web site: Open sourcing MS-DOS 4.0. 2024-04-25. Microsoft Open Source Blog.
3. 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 byte by byte, or substituted by (now freeware) 4DOS http://www.jpsoft.com/download.htm
4. While Windows ME support ended, a version of its underlying DOS is included with . 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]
6. Web site: Phystechsoft . 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. . 2016-09-19.
7. Web site: ROM-DOS Single User Version . 6.22 and 7.1 kernels . 2016-09-19.
8. http://www.86dos.org/downloads/86DOS_FILES.ZIP, A ZIP file containing most of the files from 86-DOS 0.75 (1981-04-18<
9. Web site: Standard Floppy Disk Formats Supported by MS-DOS . Microsoft Help and Support . 2003-05-12 . 2012-09-11 . 2.0.
10. Scott Mueller (1995). Upgrading and Repairing PCs, 5th Edition. Que Corporation. . 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. Xerox (1983-11). Xerox 16/8 Professional Computer - MS-DOS OS Handbook for 8" Floppy Disks. 1983-11, MS-DOS 2.0 (http://bitsavers.trailing-edge.com/pdf/xerox/820-II/610P72377_MS-DOS_OS_Handbook_for_8_Inch_Floppy_Disks_Nov83.pdf)
12. 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.
13. 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.
14. 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.
15. DOS Plus for the BBC Master 512 supports two non-standard FAT12 formats with 640 KB and 800 KB.
16. 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.