View source for MS-DOS

{{Short description|Microsoft computer operating system}}
{{About|Microsoft DOS specifically|compatible operating systems|DOS}}
{{Use mdy dates|date=September 2018}}
{{Use American English|date=September 2022}}
{{Infobox OS
| name = MS-DOS
| logo = Msdos-icon.svg
| logo_size = x64px
| screenshot = [[File:StartingMsdos.png|220px]]
| caption = The command-line interface, showing that the current directory is the root of drive C:
| developer = [[Microsoft]]
| family = [[DOS]]
| released = {{start date and age|1981|8|12}}<ref name="Linfo"/>
| discontinued = yes
| influenced_by = [[TOPS-10]], [[CP/M]]
| ui = [[Command-line interface|Command-line]] ([[COMMAND.COM]]), [[text user interface|text]] ([[DOS Shell]])
| license = {{ubl|[[Proprietary software|Proprietary]]|[[MIT License]] (v1.25, v2.0 & v4.00)<ref name="4.0-mit-relicense" />}}
| website = [https://web.archive.org/web/20160309064627/https://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/windows_dos_overview.mspx?mfr=true Internet Archive MS-DOS overview]
| source_model = [[Closed source]]; [[Open-source software|open source]] for versions 1.25, 2.11 and 4.00
| kernel_type = [[Monolithic kernel|Monolithic]]
| preceded by = [[86-DOS]]
| succeeded_by = [[Windows NT]] (since [[Windows XP]])
| supported_platforms = [[x86]]
| latest_release_version = 8.0 ([[Windows Me]])
| latest_release_date = {{start date and age|2000|9|14}}
| programmed_in = [[x86 assembly language|x86 assembly]],<ref>{{cite web |title=An Inside Look at MS-DOS |author-first=Tim |author-last=Paterson |author-link=Tim Paterson |work=[[Seattle Computer Products]] |location=Seattle |date=June 1983 |url=http://www.patersontech.com/dos/byte%E2%80%93inside-look.aspx |url-status=dead |archive-url=https://web.archive.org/web/20170506152047/http://www.patersontech.com/dos/byte%E2%80%93inside-look.aspx |archive-date=May 6, 2017 |access-date=April 16, 2016 }}</ref> later versions also used [[C (programming language)|C]]<!-- http://answers.google.com/answers/threadview?id=197874 -->
| language = [[English language|English]]
| updatemodel = Re-installation
| package_manager = None
| working_state = Preserved pieces exist in 32-bit Windows
| support_status = MS-DOS versions 1.x-7.0 unsupported as of December 31, 2001<ref name="support.microsoft.com">{{cite web |title=Obsolete Products Life-Cycle Policy |date=July 30, 2009 |website=Support |publisher=[[Microsoft]] |url=http://support.microsoft.com/gp/lifeobsoleteproducts |access-date=April 6, 2010 |url-status=dead |archive-url=https://web.archive.org/web/20060706200752/http://support.microsoft.com/gp/lifeobsoleteproducts/ |archive-date=July 6, 2006}}</ref> MS-DOS versions 7.10 and 8.0 unsupported as of July 11, 2006.
}}

'''MS-DOS''' ({{IPAc-en|ˌ|ɛ|m|ˌ|ɛ|s|ˈ|d|ɒ|s}} {{respell|em|es|DOSS}}; acronym for '''Microsoft Disk Operating System''', also known as '''Microsoft DOS''') i<!-- Do NOT change to “was” That would violate [[MOS:TENSE]], which specifies that all articles on operating systems are written in present tense, even if discontinued.
 -->s an [[operating system]] for [[x86]]-based [[personal computer]]s mostly developed by [[Microsoft]]. Collectively, MS-DOS, its rebranding as [[IBM PC&nbsp;DOS]], and a few operating systems attempting to be compatible with MS-DOS, are sometimes referred to as "DOS" (which is also the generic acronym for [[disk operating system]]). MS-DOS was the main operating system for [[IBM PC compatible]]s during the 1980s, from which point it was gradually superseded by operating systems offering a [[graphical user interface]] (GUI), in various generations of the graphical [[Microsoft Windows]] operating system.<ref name="Jerica Jean Lapuz 2023">{{Cite web |first1=Jerica Jean |last1=Lapuz |via=ResearchGate|date=2023 |title=Unveiling the Depths of Ms-Dos: An In-Depth Exploration of ITS Architecture, Commands, and Historical Significance |url=https://rgdoi.net/10.13140/RG.2.2.14329.85608 |language=en |doi=10.13140/RG.2.2.14329.85608}}</ref>

IBM licensed and re-released it in 1981 as [[PC&nbsp;DOS]] 1.0 for use in its PCs. Although MS-DOS and PC&nbsp;DOS were initially developed in parallel by Microsoft and IBM, the two products diverged after twelve years, in 1993, with recognizable differences in compatibility, syntax and capabilities.<ref name="Jerica Jean Lapuz 2023"/> Beginning in 1988 with [[DR-DOS]], [[Comparison of DOS operating systems|several competing products]] were released for the x86 platform.<ref name="roy">{{cite book |author-last=Allan |author-first=Roy A. |url=http://www.retrocomputing.net/info/allan/ |title=A history of the personal computer: the people and the technology |date=2001 |publisher=Allan Pub. |isbn=0-9689108-0-7 |location=[[London, Ontario]] |page=14 |chapter=Microsoft in the 1980s, part III 1980s&nbsp;– The IBM/Macintosh era |access-date=December 5, 2009 |archive-url=https://web.archive.org/web/20060702195053/http://www.retrocomputing.net/info/allan/ |archive-date=July 2, 2006 |url-status=dead}} [http://www.retrocomputing.net/info/allan/eBook12.pdf] {{Webarchive|url=https://web.archive.org/web/20060715184453/http://www.retrocomputing.net/info/allan/eBook12.pdf|date=July 15, 2006}}</ref>

Initially, MS-DOS was targeted at [[Intel 8086]] processors running on computer hardware using [[floppy disk]]s to store and access not only the operating system, but application software and user data as well. Progressive version releases delivered support for other mass storage media in ever greater sizes and formats, along with added feature support for newer processors and rapidly evolving computer architectures. Ultimately, it was the key product in Microsoft's development from a [[programming language]] company to a diverse software development firm, providing the company with essential revenue and marketing resources. It was also the underlying basic operating system on which early versions of Windows ran as a GUI. MS-DOS went through eight versions, until development ceased in 2000; version 6.22 from 1994 was the final standalone version, with versions 7 and 8 serving mostly in the background for loading [[Windows 9x]].<ref name="Historical Essays">{{cite web |title=A Compilation of 8 Historical Essays |url=https://books.google.com/books?id=oyto0YS-bpYC&pg=PT18 |access-date=January 30, 2016}}{{dead link|date=July 2020|bot=medic}}{{cbignore|bot=medic}}</ref>

The command interpreter, [[COMMAND.COM]], runs when no application program is running. When an application exits, the interpreter resumes {{endash}} loaded back into memory by the DOS if it was purged by the application. A command is processed by matching input text with either a [[built-in command]] or an [[executable]] [[computer file|file]] located on the current drive and along the command [[PATH (variable)|path]]. Although command and file name matching is case-insensitive, the interpreter preserves the case of parameters as input. A command with significant program size or used infrequently tended to be a separate file in order to limit the size of the command processor program.

==History==
{{Further|DOS|Timeline of DOS operating systems}}
[[File:Ms-dosdir.png|thumb|MS-DOS command prompt]]
MS-DOS was a renamed form of [[86-DOS]]<ref name="PATERSON">{{cite web |title=Father of DOS Still Having Fun at Microsoft |author-last=Conner |author-first=Doug |website=patersontech.com |publisher=Micronews |url=http://www.patersontech.com/Dos/Micronews/paterson04_10_98.htm |access-date=December 5, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20100209023553/http://www.patersontech.com/Dos/Micronews/paterson04_10_98.htm |archive-date=February 9, 2010}}</ref>{{snd}}owned by [[Seattle Computer Products]], written by [[Tim Paterson]]. Development of 86-DOS took only six weeks, as it was basically a clone of [[Digital Research]]'s [[CP/M]] (for 8080/Z80 processors), ported to run on [[8086]] processors and with two notable differences compared to CP/M: an improved disk sector buffering logic, and the introduction of [[FAT12]] instead of the [[CP/M filesystem]]. This first version was shipped in August 1980.<ref name="Linfo">{{cite web |title=MS-DOS: A Brief Introduction |work=The Linux Information Project |url=http://www.linfo.org/ms-dos.html |access-date=December 14, 2017 |url-status=live |archive-url=https://web.archive.org/web/20171214120951/http://www.linfo.org/ms-dos.html |archive-date=December 14, 2017}}</ref> Microsoft, which needed an operating system for the [[IBM Personal Computer]],<ref name="A history of Windows">{{cite web |title=A history of Windows |website=microsoft.com |publisher=[[Microsoft]] |date=November 2013 |url=http://windows.microsoft.com/en-us/windows/history |access-date=May 10, 2015 |url-status=dead |archive-url=https://web.archive.org/web/20150510042758/http://windows.microsoft.com/en-us/windows/history |archive-date=May 10, 2015}}</ref><ref name="digitalresearch.biz">{{cite web |author-first=Leven |author-last=Antov |date=1996 |title=History of MS-DOS |website=Digital Research |url=http://www.digitalresearch.biz/HISZMSD.HTM |access-date=May 6, 2015 |url-status=live |archive-url=https://web.archive.org/web/20171002211831/http://www.digitalresearch.biz/HISZMSD.HTM |archive-date=October 2, 2017}}</ref> hired Tim Paterson in May 1981 and bought 86-DOS 1.10 for {{currency|amount=25000|code=USD|fmt=commas|linked=yes}} that July.<ref>{{Cite web |title=Microsoft DOS History |url=https://www.computerhope.com/history/dos.htm |access-date=2024-05-23 |website=www.computerhope.com |language=en}}</ref> Microsoft kept the version number, but renamed it MS-DOS.<!-- The first internal version after the name change was therefore MS-DOS 1.10, not MS-DOS 1.0 --> They also licensed MS-DOS 1.10/1.14<!-- sources differ if PC DOS 1.0 was based on either MS-DOS 1.10 or 1.14 --> to IBM, which, in August 1981, offered it as [[IBM PC DOS|PC DOS]] 1.0 as one of three operating systems<ref>{{cite web |title=Personal Computer Announced by IBM |website=ibm.com |publisher=[[IBM]] |url=http://www.ibm.com/ibm/history/documents/pdf/pcpress.pdf |access-date=September 27, 2014 |archive-date=December 12, 2018 |archive-url=https://web.archive.org/web/20181212191615/https://www.ibm.com/ibm/history/documents/pdf/pcpress.pdf |url-status=live }}</ref> for the IBM 5150 or the [[IBM PC]].<ref name="Linfo"/>

Within a year, Microsoft licensed MS-DOS to over 70 other companies.<ref name="freiberger19820823">{{cite news |title=Bill Gates, Microsoft and the IBM Personal Computer |work=[[InfoWorld]] |date=August 23, 1982 |author-last=Freiberger |author-first=Paul |author-link=Paul Freiberger |pages=22 |url=https://books.google.com/books?id=VDAEAAAAMBAJ&pg=PA22 |access-date=January 29, 2015 |archive-date=February 18, 2023 |archive-url=https://web.archive.org/web/20230218183644/https://books.google.com/books?id=VDAEAAAAMBAJ&pg=PA22 |url-status=live }}</ref> It was designed to be an OS that could run on any 8086-family computer. Each computer would have its own distinct hardware and its own version of MS-DOS, similar to the situation that existed for [[CP/M]], and with MS-DOS emulating the [[CP/M BIOS|same solution]] as CP/M to adapt for different hardware platforms. To this end, MS-DOS was designed with a modular structure with internal device drivers (the [[DOS BIOS]]), minimally for primary disk drives and the console, integrated with the kernel and loaded by the boot loader, and installable device drivers for other devices loaded and integrated at boot time. The [[OEM]] would use a development kit provided by Microsoft to build a version of MS-DOS with their basic I/O drivers and a standard Microsoft kernel, which they would typically supply on disk to end users along with the hardware. Thus, there were many different versions of "MS-DOS" for different hardware, and there is a major distinction between an IBM-compatible (or ISA) machine and an MS-DOS [compatible] machine. Some machines, like the [[Tandy 2000]], were MS-DOS compatible but not IBM-compatible, so they could run software written exclusively for MS-DOS without dependence on the peripheral hardware of the IBM PC architecture.

This design would have worked well for compatibility, if application programs had used only MS-DOS services to perform device I/O. Indeed, the same design philosophy is embodied in Windows NT (see [[Hardware Abstraction Layer]]). However, in MS-DOS's early days, the greater speed attainable by programs through direct control of hardware was of particular importance, especially for games, which often pushed the limits of their contemporary hardware. Very soon an IBM-compatible architecture became the goal, and before long all 8086-family computers [[Influence of the IBM PC on the personal computer market#Domination of the clones|closely emulated IBM's hardware]], and only a single version of MS-DOS for a fixed hardware platform was needed for the market. This version is the version of MS-DOS that is discussed here, as the dozens of other OEM versions of "MS-DOS" were only relevant to the systems for which they were designed, and in any case were very similar in function and capability to some standard version for the IBM PC—often the same-numbered version, but not always, since some OEMs used their own proprietary version numbering schemes (e.g. labeling later releases of MS-DOS 1.x as 2.0 or vice versa)—with a few notable exceptions.

Microsoft omitted [[multi-user]] support from MS-DOS because Microsoft's [[Unix]]-based operating system, [[Xenix]], was fully multi-user.<ref name="swaine19820823">{{cite news |title=MS-DOS: examining IBM PC's disk-operating system |work=[[InfoWorld]] |date=August 23, 1982 |author-last=Swaine |author-first=Michael |author-link=Michael Swaine (technical author) |pages=24 |url=https://books.google.com/books?id=VDAEAAAAMBAJ&pg=PA24 |access-date=January 29, 2015 |archive-date=February 18, 2023 |archive-url=https://web.archive.org/web/20230218183644/https://books.google.com/books?id=VDAEAAAAMBAJ&pg=PA24 |url-status=live }}</ref> The company planned, over time, to improve MS-DOS so it would be almost indistinguishable from single-user Xenix, or ''XEDOS'', which would also run on the [[Motorola 68000]], [[Zilog Z8000]], and the [[LSI-11]]; they would be [[upward compatible|upwardly compatible]] with Xenix, which ''[[Byte (magazine)|Byte]]'' in 1983 described as "the multi-user MS-DOS of the future".<ref name="morgan198201">{{cite news |title=Of IBM, Operating Systems, and Rosetta Stones |work=[[BYTE]] |author-last=Morgan |author-first=Chris |page=6 |date=January 1982 |url=https://archive.org/stream/byte-magazine-1982-01/1982_01_BYTE_07-01_The_IBM_Personal_Computer#page/n7/mode/2up |access-date=October 19, 2013}}</ref><ref name="fiedler198310">{{cite news |title=The Unix Tutorial / Part 3: Unix in the Microcomputer Marketplace |work=[[BYTE]] |date=October 1983 |author-last=Fiedler |author-first=Ryan |pages=132 |url=https://archive.org/stream/byte-magazine-1983-10/1983_10_BYTE_08-10_UNIX#page/n133/mode/2up |access-date=January 30, 2015}}</ref> Microsoft advertised MS-DOS and Xenix together, listing the shared features of its "single-user OS" and "the multi-user, [[Computer multitasking|multi-tasking]], [[UNIX]]-derived operating system", and promising easy porting between them.<ref name="iw19830627">{{cite news |title=Before you bet your business software on an OS, look who's betting on MS-DOS and XENIX. |work=[[InfoWorld]] |date=June 27, 1983 |pages=44 |type=advertisement |url=https://books.google.com/books?id=yy8EAAAAMBAJ&pg=PA44 |access-date=January 31, 2015 |archive-date=February 18, 2023 |archive-url=https://web.archive.org/web/20230218183645/https://books.google.com/books?id=yy8EAAAAMBAJ&pg=PA44 |url-status=live }}</ref> After the [[breakup of the Bell System]], however, [[AT&T Computer Systems]] started selling [[UNIX System V]]. Believing that it could not compete with AT&T in the Unix market, Microsoft abandoned Xenix, and in 1987 transferred ownership of Xenix to the [[Santa Cruz Operation]] (SCO).

On March 25, 2014, Microsoft made the code to [[SCP MS-DOS 1.25]] and a mixture of [[Altos MS-DOS 2.11]] and [[TeleVideo PC DOS 2.11]] available to the public under the [[Shared Source|Microsoft Research License Agreement]], which makes the code [[source-available]], but not [[open-source software|open source]] as defined by [[Open Source Initiative]] or [[Free Software Foundation]] standards.<ref name="Paterson_2014_MSDOS125">{{cite web |author-first=Tim |author-last=Paterson |author-link=Tim Paterson |title=Microsoft DOS V1.1 and V2.0: /msdos/v11source/MSDOS.ASM |url=http://www.computerhistory.org/atchm/microsoft-research-license-agreement-msdos-v1-1-v2-0/ |publisher=[[Computer History Museum]], [[Microsoft]] |date=December 19, 2013<!-- 2014-03-25 --> |orig-year=1983-05-17 |access-date=March 25, 2014 |archive-date=August 14, 2019 |archive-url=https://web.archive.org/web/20190814021325/https://www.computerhistory.org/atchm/microsoft-research-license-agreement-msdos-v1-1-v2-0/ |url-status=live }} (NB. While the publishers claim this would be MS-DOS 1.1 and 2.0, it actually is [[SCP MS-DOS 1.25]] and a mixture of [[Altos MS-DOS 2.11]] and [[TeleVideo PC DOS 2.11]].)</ref><ref name="Shustek_2014_MS-DOS">{{Cite web |title=Microsoft MS-DOS early source code |series=Software Gems: The Computer History Museum Historical Source Code Series |author-first=Len |author-last=Shustek |date=March 24, 2014 |url=http://www.computerhistory.org/atchm/microsoft-ms-dos-early-source-code/ |access-date=March 29, 2014 |archive-date=August 10, 2019 |archive-url=https://web.archive.org/web/20190810045508/https://www.computerhistory.org/atchm/microsoft-ms-dos-early-source-code/ |url-status=live }} (NB. While the author claims this would be MS-DOS 1.1 and 2.0, it actually is [[SCP MS-DOS 1.25]] and a mixture of [[Altos MS-DOS 2.11]] and [[TeleVideo PC DOS 2.11]].)</ref><ref name="Levin_2014_MS-DOS">{{cite web |title=Microsoft makes source code for MS-DOS and Word for Windows available to public |date=March 25, 2014 |author-first=Roy |author-last=Levin |work=Official Microsoft Blog |url=https://blogs.microsoft.com/blog/2014/03/25/microsoft-makes-source-code-for-ms-dos-and-word-for-windows-available-to-public/ |access-date=March 29, 2014 |archive-date=December 14, 2017 |archive-url=https://web.archive.org/web/20171214123849/https://blogs.microsoft.com/blog/2014/03/25/microsoft-makes-source-code-for-ms-dos-and-word-for-windows-available-to-public/ |url-status=live }} (NB. While the author claims this would be MS-DOS 1.1 and 2.0, it actually is [[SCP MS-DOS 1.25]] and a mixture of [[Altos MS-DOS 2.11]] and [[TeleVideo PC DOS 2.11]].)</ref><ref>{{Cite news |title=Psych! Microsoft didn't really open-source MS-DOS |author-last=Phipps |author-first=Simon |date=March 26, 2014 |work=[[InfoWorld]] |url=http://www.infoworld.com/t/open-source-software/psych-microsoft-didnt-really-open-source-ms-dos-239111 |access-date=March 27, 2014 |archive-date=March 28, 2014 |archive-url=https://web.archive.org/web/20140328073244/http://www.infoworld.com/t/open-source-software/psych-microsoft-didnt-really-open-source-ms-dos-239111 |url-status=live }}</ref> Microsoft would later re-license the code under the [[MIT License]] on September 28, 2018, making these versions [[free software]].<ref name="mit-relicense">{{cite web |last1=Turner |first1=Rich |title=Re-Open-Sourcing MS-DOS 1.25 and 2.0 |url=https://blogs.msdn.microsoft.com/commandline/2018/09/28/re-open-sourcing-ms-dos-1-25-and-2-0/ |website=Windows Command Line Tools For Developers |date=September 28, 2018 |access-date=29 September 2018 |archive-date=September 29, 2018 |archive-url=https://web.archive.org/web/20180929011742/https://blogs.msdn.microsoft.com/commandline/2018/09/28/re-open-sourcing-ms-dos-1-25-and-2-0/ |url-status=live }}</ref> Microsoft later released the code for MS-DOS 4.00 on April 25, 2024, under the same license.<ref name="4.0-mit-relicense">{{cite web |last1=Hanselman |first1=Scott |last2=Wilcox |first2=Jeff |title=Open sourcing MS-DOS 4.0 |url=https://cloudblogs.microsoft.com/opensource/2024/04/25/open-sourcing-ms-dos-4-0/ |website=Microsoft Open Source Blog |date=2024-04-25 |access-date=2024-04-26 |archive-url=https://web.archive.org/web/20240425221026/https://cloudblogs.microsoft.com/opensource/2024/04/25/open-sourcing-ms-dos-4-0/ |archive-date=2024-04-25 |url-status=live |quote=Today, in partnership with IBM and in the spirit of open innovation, we’re releasing the source code to MS-DOS 4.00 under the MIT license.}}</ref><ref name=ars-4.0-release>{{cite news |title=Microsoft open-sources infamously weird, RAM-hungry MS-DOS 4.00 release |first=Andrew |last=Cunningham |date=26 April 2024 |journal=[[Ars Technica]] |url=https://arstechnica.com/gadgets/2024/04/microsoft-and-ibm-release-source-code-for-one-of-the-weirdest-versions-of-ms-dos/ |quote=Microsoft has open-sourced another bit of computing history this week: The company teamed up with IBM to release the source code of 1988's MS-DOS 4.00, a version better known for its unpopularity, bugginess, and convoluted development history than its utility as a computer operating system.}}</ref>

As an [[April Fool's Day]] joke in 2015, [[Microsoft Mobile]] launched a [[Windows Phone]] application called ''MS-DOS Mobile'' which was presented as a new mobile operating system and worked similar to MS-DOS.<ref name="mobile">{{Cite web |title=Microsoft launches MS-DOS Mobile |author-first=Luke |author-last=Peters |date=April 1, 2015 |website=[[Microsoft Lumia]] |url=http://lumiaconversations.microsoft.com/2015/04/01/microsoft-launches-ms-dos-mobile/ |access-date=April 2, 2015 |url-status=dead |archive-url=https://web.archive.org/web/20150402085243/http://lumiaconversations.microsoft.com/2015/04/01/microsoft-launches-ms-dos-mobile/ |archive-date=April 2, 2015 |quote=The MS-DOS Mobile preview is an essential download}}</ref>

<!-- This list of anchors for redirects to specific MS-DOS versions belong to the "Versions" chapter below. They have been moved out of the section header in order to keep the header length within reasonable limits in edit summaries. If this article has specific chapters to these versions, the anchors can be moved to the corresponding section headers. -->
{{anchor|1|1.10|1.11|1.12|1.13|1.14|1.20|1.21|1.22|1.23|1.24}}{{anchor|1.25|1.26|1.27|1.28|1.29|1.30|1.40|1.41|1.50|1.51}}{{anchor|1.52|1.53|1.54|2|2.00|2.01|2.05|2.10|2.11|2.11R|2.12|2.13}}
{{anchor|2.20|2.25|2.50|3|3.00|3.10|3.20|3.21|3.21R|3.22|3.25|3.30}}
{{anchor|3.30A|3.30R|3.31|4|4.01|5|5.00|6|6.00|6.20|6.21|6.22|7|7.00}}
{{anchor|7.10|8|8.00}}

=={{anchor|DCP|WDOS}}Versions==
{{Main|Comparison of DOS operating systems}}
{{For timeline|Timeline of DOS operating systems}}
Microsoft licensed or released versions of MS-DOS under different names like [[Lifeboat Associates]] "Software Bus 86"<ref name="Beley_1986_MS-DOS_Encyclopedia"/><ref name="Duncan_1988_MS-DOS_Encyclopedia"/> a.k.a. [[Software bus|SB-DOS]],<ref name="roy"/> [[Compaq#Introduction of Compaq Portable|COMPAQ-DOS]],<ref name="Beley_1986_MS-DOS_Encyclopedia"/><ref name="Duncan_1988_MS-DOS_Encyclopedia"/> [[NCR Corporation#Small computers|NCR-DOS]] or [[Z-DOS]]<ref name="Beley_1986_MS-DOS_Encyclopedia"/><ref name="roy"/> before it eventually enforced the MS-DOS name for all versions but the IBM one, which was originally called "IBM Personal Computer DOS", later shortened to [[IBM PC&nbsp;DOS]]. (Competitors released compatible DOS systems such as [[DR-DOS]] and [[PTS-DOS]] that could also run MS-DOS applications.)

In the former [[Eastern bloc]], MS-DOS derivatives named DCP ({{ill|Disk Control Program|de}}) 3.20 and 3.30 (DCP&nbsp;1700, DCP&nbsp;3.3) and WDOS existed in the late 1980s.<ref name="Robotron_1987_1">{{cite book |title=Programmtechnische Beschreibung - Arbeitsplatzcomputer A 7150 Betriebssystem DCP 1700 - Kompendium |id=C3013-0001-1 M3030 Ag&nbsp;706/169/88-5749 |language=de |publisher=[[VEB Robotron-Projekt Dresden]] |version=3.20 |location=Dresden, East-Germany |date=December 1987 |url=http://www.tiffe.de/Robotron/MMS16/Doku/A7150/A_7150__DCP_1700_KOMPENDIUM_Programmtechnische_Beschreibung.pdf |access-date=2021-12-03 |url-status=live |archive-url=https://web.archive.org/web/20170123202425/http://www.tiffe.de/Robotron/MMS16/Doku/A7150/A_7150__DCP_1700_KOMPENDIUM_Programmtechnische_Beschreibung.pdf |archive-date=2017-01-23}}</ref><ref name="Robotron_1987_2">{{cite book |title=Anwenderdokumentation - Anleitung für den Systemprogrammierer - MOS DCP 1700 |id=C3013-0000-0 M3030, Textdiskette DCP1700 T1/2 C3010-9991-2M3020, Disk-Nr.: 5962 /88 ROBOTRON PROJEKT DRESDEN KA2 DD-DS 80*16*256 |language=de |publisher=[[VEB Robotron-Projekt Dresden]] |version=3.20 |location=Dresden, East-Germany |date=1988-01-29 |url=http://www.robotron-net.de/Service/Dokus/DCP20sys.pdf |access-date=2021-12-03 |url-status=live |archive-url=https://web.archive.org/web/20210829191036/http://www.robotron-net.de/Service/Dokus/DCP20sys.pdf |archive-date=2021-08-29}}</ref><ref name="P8000_2020">{{cite web |date=2020-02-10 |title=Computer P8000 compact |url=https://www.robotrontechnik.de/html/computer/p8000compact.htm |url-status=live |archive-url=https://web.archive.org/web/20201026125454/https://www.robotrontechnik.de/index.htm?/html/computer/p8000compact.htm |archive-date=2020-10-26 |access-date=2021-12-03 |website=robotrontechnik.de |language=de}} [https://www.robotrontechnik.de/html/software/os.htm] {{Webarchive|url=https://web.archive.org/web/20211203182254/https://www.robotrontechnik.de/html/software/os.htm|date=December 3, 2021}}</ref> They were produced by the [[East German]] electronics manufacturer [[VEB Robotron]].<ref name="DCP_2016"/>

The following versions of MS-DOS were released to the public:<ref>{{cite web |title=Microsoft DOS Version Features |website=EMS Professional Software and Specialty Services |url=http://www.emsps.com/oldtools/msdosv.htm |access-date=August 29, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170829034033/http://www.emsps.com/oldtools/msdosv.htm |archive-date=August 29, 2017}}</ref><ref>{{cite web |title=DOS history |website=Pcmuseum.tripod.com |url=http://pcmuseum.tripod.com/dos.htm |access-date=August 29, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170829034443/http://pcmuseum.tripod.com/dos.htm |archive-date=August 29, 2017}}</ref>

===MS-DOS 1.x===
[[File:Compaq mddos ver1-12.jpg|thumb|MS-DOS (Compaq-DOS) version 1.12 (based on MS-DOS 1.25) for Compaq Personal Computer]]
<!-- * Versions 1.11, 1.12 and 1.13 (Microsoft internal) -->
<!-- * Versions 1.20, 1.21, 1.22 (Microsoft internal) -->
* Version 1.23 (OEM)<ref>{{cite web|title=Customizing MS-DOS 1.23 and Later|url=https://bitsavers.org/pdf/seattleComputer/Customizing_MS-DOS_1.23_and_Later.pdf|website=bitsavers.org|access-date=December 20, 2024}}</ref>
* Version 1.24 (OEM)&nbsp;– basis for IBM's Personal Computer DOS 1.1
* Version 1.25 (OEM)&nbsp;– basis for non-IBM OEM versions of MS-DOS, including [[SCP MS-DOS 1.25]]
<!-- * Versions 1.26, 1.27, 1.28, 1.29, 1.30, 1.40, 1.41, 1.50, 1.51, 1.52, 1.53 and 1.54 (Microsoft internal) --><!-- or at least the corresponding OEM versions are not known -->
<!-- Note: The following OEM versions of MS-DOS had their own version numbering schemes different from MS-DOS, therefore they must be listed separately unless the corresponding MS-DOS version is known -->
::* Compaq-DOS 1.12, a Compaq OEM version of MS-DOS 1.25; Release date: November 1983<ref>{{Cite web|url=http://16bitos.com/112ms.htm|title=16BitOS - MS-DOS® Version 1.12 - Compaq OEM|accessdate=March 3, 2021|archive-date=October 2, 2020|archive-url=https://web.archive.org/web/20201002042421/http://16bitos.com/112ms.htm|url-status=live}}</ref>
::* TI BOOT V. 1.13, a Texas Instruments OEM version of MS-DOS; Release date: August 1983<ref>{{Cite web|url=http://16bitos.com/113ms.htm|title=16BitOS - MS DOS® Version 1.13 - Texas Instruments OEM|accessdate=March 3, 2021|archive-date=October 1, 2020|archive-url=https://web.archive.org/web/20201001231218/http://16bitos.com/113ms.htm|url-status=dead}}</ref>
::* Zenith Z-DOS 1.19, a Zenith OEM version of MS-DOS 1.25<ref>{{cite web |title=Microsoft MS-DOS Informatie |website=ultrawindows.nl |url=http://www.ultrawindows.nl/tmp/msdos/119 |access-date=September 27, 2012 |url-status=dead |archive-url=https://web.archive.org/web/20110809151845/http://www.ultrawindows.nl/tmp/msdos/119/ |archive-date=August 9, 2011}}</ref>
::* Zenith Z-DOS/MS-DOS release 1.01, version 1.25, a Zenith OEM version of MS-DOS; Release date: May 1983<ref>{{Cite web|url=http://16bitos.com/113ms.htm|title=16BitOS - MS DOS® Version 1.25 - Zenith OEM|accessdate=March 3, 2021|archive-date=October 1, 2020|archive-url=https://web.archive.org/web/20201001231218/http://16bitos.com/113ms.htm|url-status=dead}}</ref>

=== MS-DOS 2.x ===
[[File:Leading Edge Model D Boot Disk for MS-DOS 2.11.png|thumbnail|MS-DOS 2.11 boot disk for the [[Leading Edge Model D]] in its sleeve]]

Popular because of reliability and use of less memory than version 3.<ref name="byte198710">{{cite news | url=https://archive.org/stream/byte-magazine-1987-10-rescan/1987_10_BYTE_12-11_Heuristic_Algorithms#page/n103/mode/2up | title=The Tandy Anniversary Product Explosion | work=BYTE | date=October 1987 | access-date=4 August 2014 |author1=Malloy, Rich |author2=Vose, G. Michael |author3=Stewart, George A. | pages=100}}</ref> Support for IBM's XT 10 MB hard disk drives, support up to 16 MB or 32 MB [[FAT12]]-formatted hard disk drives depending on the formatting tool shipped by OEMs,<ref name="Mueller_1995_Upgrading_and_Repairing_PCs">{{cite book |author-first=Scott |author-last=Mueller |date=1995 |title=Upgrading and Repairing PCs |edition=5th |publisher=[[Que Corporation]] |isbn=0-7897-0321-1 |page=784 |quote=The limit of 16 MB 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 32 MB to be formatted properly.}}</ref> user-installable device drivers, tree-structure filing system,<ref>{{cite web |title=Short History of MS-DOS |url=http://www.skrause.org/computers/dos_history.shtml |access-date=July 8, 2018 |archive-date=July 8, 2018 |archive-url=https://web.archive.org/web/20180708040656/http://www.skrause.org/computers/dos_history.shtml |url-status=live }}</ref> Unix-like<ref>{{cite web |title=DOS 2.0 and 2.1: Hello, UNIX! |website=OS/2 Museum |url=http://www.os2museum.com/wp/dos/dos-2-0-and-2-1/ |access-date=July 29, 2018 |archive-date=June 12, 2018 |archive-url=https://web.archive.org/web/20180612143857/http://www.os2museum.com/wp/dos/dos-2-0-and-2-1/ |url-status=live }}</ref> inheritable redirectable file handles,<ref>{{cite web |title=DOS 2+ - OPEN&nbsp;— Open Existing File |website=[[Ralf Brown's Interrupt List]] |url=http://www.ctyme.com/intr/rb-2779.htm |access-date=July 10, 2018 |archive-date=July 15, 2019 |archive-url=https://web.archive.org/web/20190715050536/http://www.ctyme.com/intr/rb-2779.htm |url-status=live }}</ref><ref>{{cite web |title=DOS 2+ - DUP&nbsp;— Duplicate File Handle |website=[[Ralf Brown's Interrupt List]] |url=http://www.ctyme.com/intr/rb-2931.htm |access-date=June 10, 2018 |archive-date=July 15, 2019 |archive-url=https://web.archive.org/web/20190715050527/http://www.ctyme.com/intr/rb-2931.htm |url-status=live }}</ref> non-multitasking child processes<ref>{{cite web |title=DOS 2+ - EXEC&nbsp;— Load And/Or Execute Program |website=[[Ralf Brown's Interrupt List]] |url=http://www.ctyme.com/intr/rb-2939.htm |access-date=June 10, 2018 |archive-date=November 16, 2017 |archive-url=https://web.archive.org/web/20171116024937/http://www.ctyme.com/intr/rb-2939.htm |url-status=live }}</ref> an improved Terminate and Stay Resident (TSR) API,<ref>{{cite web |title=DOS 2+ - Terminate And Stay Resident |website=[[Ralf Brown's Interrupt List]] |url=http://www.ctyme.com/intr/rb-2723.htm |access-date=June 10, 2018 |archive-date=September 27, 2017 |archive-url=https://web.archive.org/web/20170927152821/http://www.ctyme.com/intr/rb-2723.htm |url-status=live }}</ref> environment variables, device driver support, FOR and GOTO loops in batch files, [[ANSI.SYS]].<ref>{{cite web |title=History of DOS |website=PC DOS Retro |url=https://pcdosretro.github.io/doshist.txt |access-date=July 29, 2018 |archive-date=February 21, 2020 |archive-url=https://web.archive.org/web/20200221141546/https://sites.google.com/site/pcdosretro/doshist |url-status=live }}</ref>

* Version 2.0 (OEM), First version to support double-sided 360 KB 5.25-inch floppy disks;<ref name="Microsoft">{{Cite web |title=Standard Floppy Disk Formats Supported by MS-DOS |website=Microsoft Support |publisher=[[Microsoft]] |url=https://jeffpar.github.io/kbarchive/kb/075/Q75131/ |access-date=June 11, 2018 |url-status=live |archive-url=https://web.archive.org/web/20160304062122/https://support.microsoft.com/en-us/kb/75131 |archive-date=March 4, 2016}}</ref><ref>{{cite magazine |title=DOS Marches On |magazine=PC: The Independent Guide to IBM Personal Computers |author-first=David |author-last=Rose |volume=1 |issue=12 |pages=108–125 |url=https://archive.org/stream/PC-Mag-1983-04#page/n109/mode/1up |access-date=July 8, 2018}}</ref> Release date: October 1983<ref>{{Cite web|url=http://16bitos.com/200ms.htm|title=16BitOS - MS DOS® Version 2.00 - NCR OEM|accessdate=March 3, 2021|archive-date=October 8, 2020|archive-url=https://web.archive.org/web/20201008143507/http://16bitos.com/200ms.htm|url-status=live}}</ref>
* Version 2.02 (OEM, Compaq); Release date: November 1983<ref>{{Cite web|url=http://16bitos.com/202ms.htm|title=16BitOS - MS DOS® Version 2.02 - Compaq OEM|accessdate=March 3, 2021|archive-date=October 2, 2020|archive-url=https://web.archive.org/web/20201002031013/http://16bitos.com/202ms.htm|url-status=live}}</ref>
* Version 2.05 (OEM, international support);<ref name="Beley_1986_MS-DOS_Encyclopedia"/> Release date: October 1983<ref>{{Cite web|url=http://16bitos.com/205ms.htm|title=16BitOS - MS DOS® Version 2.05 - Digital OEM|accessdate=March 3, 2021|archive-date=October 1, 2020|archive-url=https://web.archive.org/web/20201001201135/http://16bitos.com/205ms.htm|url-status=dead}}</ref>
* Version 2.1 (OEM, IBM only)<ref name="Beley_1986_MS-DOS_Encyclopedia"/>
* Version 2.11 (OEM)<ref name="Beley_1986_MS-DOS_Encyclopedia"/>
** [[Altos Computer Systems|Altos]] MS-DOS 2.11, an Altos OEM version of MS-DOS 2.11 for the ACT-86C
** [[ITT Corporation]] ITT-DOS 2.11 Version 2 (MS-DOS 2.11 for the ITT XTRA Personal Computer); Release date: July 1985<ref>{{Cite web|url=http://16bitos.com/211ms.htm|title=16BitOS - MS DOS® Version 2.11 - ITT OEM|accessdate=March 3, 2021|archive-date=February 15, 2020|archive-url=https://web.archive.org/web/20200215202531/http://16bitos.com/211ms.htm|url-status=live}}</ref>
** [[Olivetti M19]] came with MS-DOS 2.11<ref>{{cite web |url=https://www.sba.unipi.it/sites/default/files/10.pdf |title=Personal Computer M19 |publisher=Olivetti |language=it |access-date=December 29, 2021 |url-status=live |archive-date=October 27, 2021 |archive-url=https://web.archive.org/web/20211027011518/https://www.sba.unipi.it/sites/default/files/10.pdf }}</ref>
** [[Tandy 1000#Tandy 1000 EX and HX|Tandy 1000 HX]] has MS-DOS 2.11 in ROM{{r|byte198710}}
** [[TeleVideo]] PC DOS 2.11<!-- yes, PC DOS, not MS-DOS -->, a TeleVideo OEM version of MS-DOS 2.11
** [[Toshiba]] MS-DOS 2.11 in ROM drive for the model [[Toshiba T1000|T1000]] laptop
* Version 2.13 (OEM, Zenith); Release date: July 1984<ref>{{Cite web|url=http://16bitos.com/213ms.htm|title=16BitOS - MS DOS® Version 2.13 - Zenith OEM|accessdate=March 3, 2021|archive-date=October 8, 2020|archive-url=https://web.archive.org/web/20201008120818/http://16bitos.com/213ms.htm|url-status=live}}</ref>
* Version 2.2 (OEM, with Hangeul support)<ref name="Beley_1986_MS-DOS_Encyclopedia"/>
* Version 2.25 (OEM, with Hangeul and Kanji support)<ref name="Beley_1986_MS-DOS_Encyclopedia"/>
* Version 2.3 (used on the [[Toshiba Pasopia 16]])<ref>{{cite web |url=https://www.old-computers.com/museum/computer.asp?st=1&c=414 |title=Toshiba Pasopia 16/T300/PAP |website=old-computers.com |access-date=December 29, 2021 |url-status=dead |archive-date=December 9, 2021 |archive-url=https://web.archive.org/web/20211209014836/https://www.old-computers.com/MUSEUM/computer.asp?st=1&c=414 }}</ref>

=== MS-DOS 3.x ===
[[File:NEC MS-DOS 3.3C.jpg|thumb|MS-DOS 3.3C for the [[PC-9800 series]]]]
* Version 3.0 (OEM)&nbsp;– First version to support 5.25-inch 1.2 MB floppy drives and diskettes, [[FAT16]] partitions up to 32 MB;<ref name="DOS3_OS2MUSEUM">{{cite web |url=http://www.os2museum.com/wp/dos/dos-3-0-3-2/ |title=DOS 3.0, 3.1, and 3.2: The Networked PC/AT |website=OS/2 Museum |access-date=June 10, 2018 |archive-date=June 12, 2018 |archive-url=https://web.archive.org/web/20180612143813/http://www.os2museum.com/wp/dos/dos-3-0-3-2/ |url-status=live }}</ref><ref>{{cite magazine |author-first=Paul |author-last=Somerson |title=DOS 3.0 Is Bigger, but Only Manual is Better |url=https://archive.org/stream/PC-Mag-1984-10-16#page/n41/mode/1up |magazine=PC: The Independent Guide to the IBM Personal Computer |date=October 16, 1984 |page=40 |volume=3 |issue=20}}</ref> Release date: April 1985<ref>{{Cite web|url=http://16bitos.com/300ms.htm|title=16BitOS - MS DOS® Version 3.00 - Compaq OEM|accessdate=March 3, 2021|archive-date=October 1, 2020|archive-url=https://web.archive.org/web/20201001231218/http://16bitos.com/300ms.htm|url-status=dead}}</ref>
* Version 3.1 (OEM)&nbsp;– Support for Microsoft Networks through an [[Installable File System|IFS]] layer,<ref name="DOS3_OS2MUSEUM"/> remote file and printer API<ref>{{cite web |title=DOS 3.1+ - IOCTL&nbsp;— Check If Handle Is Remote |website=[[Ralf Brown's Interrupt List]] |url=http://www.ctyme.com/intr/rb-2892.htm |access-date=June 10, 2018 |archive-date=July 15, 2019 |archive-url=https://web.archive.org/web/20190715050522/http://www.ctyme.com/intr/rb-2892.htm |url-status=live }}</ref><ref>{{cite web |title=DOS 3.1+ network&nbsp;— Get Network Printer Setup String |website=[[Ralf Brown's Interrupt List]] |url=http://www.ctyme.com/intr/rb-3034.htm |access-date=June 10, 2018 |archive-date=July 15, 2019 |archive-url=https://web.archive.org/web/20190715050437/http://www.ctyme.com/intr/rb-3034.htm |url-status=live }}</ref>
* Version 3.2 (OEM)&nbsp;– First version to support 3.5-inch 720 KB floppy drives and diskettes and [[XCOPY]].<ref name="Microsoft"/>
* Version 3.10 (OEM, [[Multitech]]); Release date: May 1986<ref>{{Cite web|url=http://16bitos.com/310ms.htm|title=16BitOS - MS DOS® Version 3.10 - Multitech OEM|accessdate=March 3, 2021|archive-date=October 1, 2020|archive-url=https://web.archive.org/web/20201001230019/http://16bitos.com/310ms.htm|url-status=live}}</ref>
* Version 3.20 – First retail release (non-OEM); Release date: July 1986<ref>{{Cite web|url=http://16bitos.com/320ms.htm|title=16BitOS - MS-DOS® Version 3.20|accessdate=March 3, 2021|archive-date=October 2, 2020|archive-url=https://web.archive.org/web/20201002010321/http://16bitos.com/320ms.htm|url-status=live}}</ref>
* Version 3.21 (OEM / non-OEM); Release date: May 1987<ref>{{Cite web|url=http://16bitos.com/321ms.htm|title=16BitOS - MS DOS® Version 3.21|accessdate=March 3, 2021|archive-date=October 1, 2020|archive-url=https://web.archive.org/web/20201001231218/http://16bitos.com/321ms.htm|url-status=dead}}</ref>
* Version 3.22 (OEM)&nbsp;– ([[HP 95LX]])
* Version 3.3 (OEM)&nbsp;– First version to support 3.5-inch 1.44 MB floppy drives and diskettes, extended and logical partitions, directory tree copying with XCOPY, improved support for internationalization (COUNTRY.SYS),<ref>{{cite web |title=DOS 3.3: The Mature DOS |website=OS/2 Museum |url=http://www.os2museum.com/wp/dos/dos-3-3/ |access-date=June 10, 2018 |archive-date=June 17, 2017 |archive-url=https://web.archive.org/web/20170617164908/http://www.os2museum.com/wp/dos/dos-3-3/ |url-status=live }}</ref> networked file flush operations<ref>{{cite web |title=DOS 3.3+ - FFLUSH&nbsp;— Commit File |website=[[Ralf Brown's Interrupt List]] |url=http://www.ctyme.com/intr/rb-3170.htm |access-date=June 10, 2018 |archive-date=July 15, 2019 |archive-url=https://web.archive.org/web/20190715050604/http://www.ctyme.com/intr/rb-3170.htm |url-status=live }}</ref>
* Version 3.3a (OEM)
* Version 3.30; Release date: February 1988<ref>{{Cite web|url=http://16bitos.com/330ms.htm|title=16BitOS - MS-DOS® Version 3.30|accessdate=March 3, 2021|archive-date=October 1, 2020|archive-url=https://web.archive.org/web/20201001211101/http://16bitos.com/330ms.htm|url-status=live}}</ref>
* Version 3.30A (OEM, [[DTK Corporation|DTK]]); Release date: July 1987<ref>{{Cite web|url=http://16bitos.com/330ams.htm|title=16BitOS - MS-DOS® Version 3.30A DTK OEM|accessdate=March 3, 2021|archive-date=October 2, 2020|archive-url=https://web.archive.org/web/20201002003734/http://16bitos.com/330ams.htm|url-status=live}}</ref>
* Version 3.30T (OEM, [[Tandy Corporation|Tandy]]); Release date: July 1990<ref>{{Cite web|url=http://16bitos.com/330tms.htm|title=16BitOS - MS-DOS® Version 3.30T - Tandy OEM|accessdate=March 3, 2021|archive-date=October 7, 2020|archive-url=https://web.archive.org/web/20201007121735/http://16bitos.com/330tms.htm|url-status=live}}</ref>
* Version 3.31 (Compaq, Emerson and Vendex HeadStart Explorer OEM only)<ref group="nb">Confirmed that there was Compaq Personal Computer DOS 3.31 aside from MS-DOS 3.31.</ref>&nbsp;– supports [[FAT16B]] with partitions larger than 32 MiB;<ref group="nb">Up to 512 MB only.</ref> Release date: November 1987

=== MS-DOS 4.0 / MS-DOS 4.x ===
* [[MS-DOS 4.0 (multitasking)]] and MS-DOS 4.1{{snd}}A separate branch of development with additional multitasking features, released between 3.2 and 3.3, and later abandoned. It is unrelated to any later versions, including versions 4.00 and 4.01 listed below
* MS-DOS 4.x (IBM-developed)&nbsp;– Includes a graphical/mouse interface. It had many bugs and compatibility issues that plagued all versions of MS-DOS 4.x.<ref>{{cite web |title=Dinosaur Sightings: Installing MS-DOS 4 |author-last=Shultz |author-first=Greg |date=November 6, 2006 |website=[[TechRepublic]] |publisher=[[CBS Interactive]] |url=https://www.techrepublic.com/pictures/dinosaur-sightings-installing-ms-dos-4/?mobileView=fullonce |access-date=August 29, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170829202303/https://www.techrepublic.com/pictures/dinosaur-sightings-installing-ms-dos-4/?mobileView=fullonce |archive-date=August 29, 2017}}</ref><ref name=ars-4.0-release />
** Version 4.00 (OEM)&nbsp;– First version with built-in IBM/Microsoft support for hard disk partitions larger than 32 MB and up to a maximum size of 2 GB,<ref name="MS-DOS Partitioning Summary">{{cite web |title=MS-DOS Partitioning Summary |website=Support |publisher=[[Microsoft]] |url=http://c-bit.org/kb/69912/EN-US/ |access-date=June 11, 2018 |archive-date=June 12, 2018 |archive-url=https://web.archive.org/web/20180612143554/http://c-bit.org/kb/69912/EN-US/ |url-status=dead }}</ref> [[FASTOPEN]]/FASTSEEK, [[DOSSHELL]], could use [[Expanded memory|EMS]] for the disk buffers and provided EMS drivers and emulation for [[i386|386]]-compatible processors;<ref name="DOS4_OS2MUSEUM">{{cite web |title=DOS 4.0: the apparent cul-de-sac |website=OS/2 Museum |url=http://www.os2museum.com/wp/dos/dos-4-0/ |access-date=June 10, 2018 |archive-date=June 12, 2018 |archive-url=https://web.archive.org/web/20180612140733/http://www.os2museum.com/wp/dos/dos-4-0/ |url-status=live }}</ref> Release date: October 1988<ref>{{Cite web|url=http://16bitos.com/400ms.htm|title=16BitOS - MS-DOS® Version 4.00|accessdate=March 3, 2021|archive-date=October 2, 2020|archive-url=https://web.archive.org/web/20201002052027/http://16bitos.com/400ms.htm|url-status=live}}</ref>
** Version 4.01 (OEM)&nbsp;– Microsoft-rewritten Version 4.00 released under MS-DOS label but not IBM PC DOS. First version to introduce volume serial number when formatting hard disks and floppy disks (Disk duplication also<ref group="nb">Only if boot record of source floppy disk contains volume serial number also.</ref> and when using [[SYS (DOS command)|SYS]] to make a floppy disk or a hard drive partition bootable);<ref>{{cite web |title=DOS 4.0: About volume serial number |website=Faqs.org |url=http://www.faqs.org/faqs/assembly-language/x86/general/part3/ |access-date=September 27, 2012 |archive-date=October 10, 2012 |archive-url=https://web.archive.org/web/20121010132518/http://www.faqs.org/faqs/assembly-language/x86/general/part3/ |url-status=live }}</ref> Release date: April 1989<ref>{{Cite web|url=http://16bitos.com/401ms.htm|title=16BitOS - MS-DOS® Version 4.01|accessdate=March 3, 2021|archive-date=October 7, 2020|archive-url=https://web.archive.org/web/20201007172924/http://16bitos.com/401ms.htm|url-status=live}}</ref>
** Version 4.01a (OEM)

=== MS-DOS 5.x ===
[[File:Disquetes instalacion MSDOS 50.jpg|thumb|MS-DOS version 5.0]]
* Version 5.0 (Retail)&nbsp;– includes a [[MS-DOS Editor|full-screen text editor]]. Many of the bugs and compatibility issues from MS-DOS 4.x are resolved. First version to support 3.5-inch 2.88 MB floppy drives and diskettes. The [[Share (command)|SHARE]] command was not needed anymore for old DOS&nbsp;1.x style [[File Control Block|FCB]] file [[API]] to partitions over 32 MB.<ref name="DOS4_OS2MUSEUM"/><ref name="MS-DOS Partitioning Summary"/> First version to get the [[HIMEM.SYS]] driver and load portions of the operating system into the [[upper memory area]] and [[high memory area]]. Supports up to four DOS [[primary partition]]s, however [[FDISK]] cannot create more than one primary partition. Third-party tools allowed for the creation of up to four primary partitions.
** AST Premium Exec DOS 5.0 (OEM){{snd}}a version for the [[AST Premium Exec]] series of notebooks with various extensions, including improved load-high and extended [[codepage]] support<ref name="RBIL">{{Cite web |title=The x86 Interrupt List |author-last=Brown |author-first=Ralf D. |author-link=Ralf D. Brown |via=Carnegie Mellon University |date=December 29, 2002 |url=https://www.cs.cmu.edu/~ralf/files.html |access-date=October 14, 2011 |archive-date=August 22, 2017 |archive-url=https://web.archive.org/web/20170822194456/https://www.cs.cmu.edu/~ralf/files.html |url-status=live }}</ref><ref name="Paul_1997_NWDOSTIP">{{cite book |author-last=Paul |author-first=Matthias R. |url=http://www.antonis.de/dos/dos-tuts/mpdostip/html/nwdostip.htm |title=NWDOS-TIPs&nbsp;– Tips & Tricks rund um Novell DOS 7, mit Blick auf undokumentierte Details, Bugs und Workarounds |date=1997-07-30 |edition=3 |version=Release 157 |language=de |trans-title=NWDOSTIPs&nbsp;– Tips & tricks for Novell DOS 7, with special focus on undocumented details, bugs and workarounds |chapter=II.16.iv. Landessprachliche Unterstützung&nbsp;– Codeseiten |trans-chapter=II.16.iv. National language support&nbsp;– Codepages |access-date=2016-06-06 |orig-year=1994-05-01 |archive-url=https://web.archive.org/web/20160606185230/http://www.antonis.de/dos/dos-tuts/mpdostip/html/nwdostip.htm |archive-date=2016-06-06 |url-status=live}}<!-- The provided link points to a HTML-converted older version of the NWDOSTIP.TXT file.--> [https://web.archive.org/web/20190601152204/https://www.sac.sk/download/text/mpdostip.zip]</ref>
* Version 5.0a (Retail)&nbsp;– With this release, IBM and Microsoft versions diverge.
* [[MS-DOS 5.50|Version 5.50]] (Windows [[NTVDM]])&nbsp;– All Windows NT [[32-bit]] versions ship with files from DOS 5.0

=== {{anchor|6.0|6.2|6.21|6.22}} MS-DOS 6.x ===
[[File:MS-DOS 6.2 Update Install Floppy Discs (German).jpg|thumb|German MS-DOS 6.2 Update]]
[[File:MS-DOS 6.22 floppy disks 20110326.jpg|thumb|MS-DOS version 6.22]]
* Version 6.0 (Retail)&nbsp;– Online help through [[QBasic]]. Disk compression, upper memory optimization and antivirus included.
* Version 6.2&nbsp;– [[SCANDISK]] as replacement for [[CHKDSK]]. Fix serious bugs in [[DBLSPACE]].
* Version 6.21 (Retail)&nbsp;– Stacker-infringing DBLSPACE removed.
* Version 6.22 (Retail)&nbsp;– New [[DRVSPACE]] compression.<ref>{{cite web |title=MS-DOS 6 Technical Reference |url=https://technet.microsoft.com/en-us/library/cc743186.aspx |archive-url=https://web.archive.org/web/20140127150747/https://technet.microsoft.com/en-us/library/cc743186.aspx |archive-date=January 27, 2014 |access-date=February 13, 2014 |website=[[Microsoft TechNet|TechNet]] |publisher=[[Microsoft]]}}</ref> Last version of MS-DOS to be sold as an independent product.

=== MS-DOS 7/8 (as part of Windows 9x) ===
{{Main|MS-DOS 7|Windows 9x}}
* MS-DOS 7.0 was included in [[Windows 95]]'s first retail release. It contains support for [[VFAT]] long file names when run in a Windows [[Virtual 8086 mode|Virtual 8086]] box or with an [[Long filename#VFAT LFN drivers|LFN driver]] such as DOSLFN. JO.SYS is an alternative filename of the [[IO.SYS]] kernel file and used as such for "special purposes". JO.SYS allows booting from either CD-ROM drive or hard disk. Last version to recognize only the first 8.4&nbsp;GB of a hard disk. The [[VER (DOS command)|VER]] internal command reports the Windows version 4.00.950, applications through the [[MS-DOS API]] would be reported a version number of 7.00.
* MS-DOS 7.1 was included in [[Windows 95]]'s OEM Service Release 2 through [[Windows 98]] Second Edition. It added support for the [[FAT32]] file system and [[logical block addressing]] (LBA), and was the last version that could boot to the command line from a hard disk. The VER internal command reports the Windows version 4.00.1111, 4.10.1998, or 4.10.2222 depending on the version of Windows, while applications through the API would report version 7.10.
* MS-DOS 8.0 was included in [[Windows Me]], the last version based on MS-DOS. DOS mode was significantly altered in this release. Booting from the hard disk to a command line only was no longer permitted, AUTOEXEC.BAT and CONFIG.SYS files were no longer loaded or parsed before loading the Windows GUI; booting from floppy disk was still permitted to allow for emergency recovery. This version was included (in modified form) in [[Windows XP]] up to [[Windows 8.1]] for creating MS-DOS startup disks. The VER internal command reports the Windows version 4.90.3000 or 5.1 when created from newer versions of Windows. Applications requesting the version through the API would report version 8.00.

Microsoft DOS was released through the OEM channel, until Digital Research released [[DR DOS 5.0|DR-DOS 5.0]] as a retail upgrade. With [[IBM PC DOS|PC&nbsp;DOS]] 5.00.1, the IBM–Microsoft agreement started to end, and IBM entered the retail DOS market with IBM DOS 5.00.1, 5.02, 6.00 and PC&nbsp;DOS 6.1, 6.3, 7, 2000 and 7.1.

==={{anchor|ADOS|HDOS}}Localized versions===
[[File:MS-DOS 6.2V floppy disks.jpg|thumb|Japanese MS-DOS 6.2/V]]
Localized versions of MS-DOS existed for different markets.<ref name="country">{{Cite web |url=https://technet.microsoft.com/en-us/library/cc722862.aspx#XSLTsection136121120120 |title=Country |website=MS-DOS 6 Technical Reference |publisher=[[Microsoft]] |at=ANSI.SYS |access-date=April 1, 2014 |via=[[Microsoft TechNet|TechNet]] |archive-date=February 16, 2014 |archive-url=https://web.archive.org/web/20140216013029/http://technet.microsoft.com/en-us/library/cc722862.aspx#XSLTsection136121120120 |url-status=live }}</ref> While Western issues of MS-DOS evolved around the same set of tools and drivers just with localized message languages and differing sets of supported codepages and keyboard layouts, some language versions were considerably different from Western issues and were adapted to run on localized PC hardware with additional BIOS services not available in Western PCs, support multiple hardware codepages for displays and printers, support DBCS, alternative input methods and graphics output. Affected issues include Japanese ([[DOS/V]]), Korean, Arabic (ADOS 3.3/5.0), Hebrew (HDOS 3.3/5.0), Russian ([[Russian MS-DOS 4.01|RDOS 4.01]]/[[Russian MS-DOS 5.0|5.0]]) as well as some other Eastern European versions of DOS.

==Competition==
{{more citations needed section|date=April 2010}}
[[Image:Msdosad.jpg|left|thumb|The original MS-DOS advertisement in 1981]]

On microcomputers based on the [[Intel 8086]] and [[Intel 8088|8088]] processors, including the IBM PC and clones, the initial competition to the PC DOS/MS-DOS line came from [[Digital Research]], whose [[CP/M]] operating system had inspired MS-DOS. In fact, there remains controversy as to whether QDOS was more or less plagiarized from early versions of CP/M code. Digital Research released [[CP/M-86]] a few months after MS-DOS, and it was offered as an alternative to MS-DOS and Microsoft's licensing requirements, but at a higher price. [[Executable]] programs for CP/M-86 and MS-DOS were not interchangeable with each other; many [[application software|applications]] were sold in both MS-DOS and CP/M-86 versions until MS-DOS became preponderant (later Digital Research operating systems could run both MS-DOS and CP/M-86 software). MS-DOS originally supported the simple [[COM file|.COM]], which was modeled after a similar but binary-incompatible format known from [[CP/M-80]]. CP/M-86 instead supported a [[Relocation (computing)|relocatable]] format using the [[filename extension]] [[CMD file (CP/M)|.CMD]] to avoid name conflicts with CP/M-80 and MS-DOS .COM files. MS-DOS version 1.0 added a more advanced relocatable .[[EXE]] executable file format.

Most of the machines in the early days of MS-DOS had differing system architectures and there was a certain degree of incompatibility, and subsequently [[vendor lock-in]]. Users who began using MS-DOS with their machines were compelled to continue using the version customized for their hardware, or face trying to get all of their proprietary hardware and software to work with the new system.

In the business world, the 808x-based machines that MS-DOS was tied to faced competition from the [[Unix]] operating system; the latter ran on many different hardware architectures. Microsoft itself sold a version of Unix for the PC called [[Xenix]].

In the emerging world of home users, a variety of other computers based on various other processors were in serious competition with the IBM PC: the [[Apple II]], [[Mac (computer)|Mac]], [[Commodore 64]] and others did not use the 808x processor; many 808x machines of different architectures used custom versions of MS-DOS. At first all these machines were in competition. In time the IBM PC hardware configuration became dominant in the 808x market as software written to communicate directly with the PC hardware without using standard operating system calls ran much faster, but on true PC-compatibles only. Non-PC-compatible 808x machines were too small a market to have fast software written for them alone, and the market remained open only for IBM PCs and machines that closely imitated their architecture, all running either a single version of MS-DOS compatible only with PCs, or the equivalent IBM PC DOS. Most clones cost much less than IBM-branded machines of similar performance, and became widely used by home users, while IBM PCs had a large share of the business computer market.

Microsoft and IBM together began what was intended as the follow-on to MS-DOS/PC DOS, called [[OS/2]]. When OS/2 was released in 1987, Microsoft began an advertising campaign announcing that "DOS is Dead" and stating that version 4 was the last full release. OS/2 was designed for efficient multi-tasking and offered a number of advanced features that had been designed together with similar [[look and feel]]; it was seen as the legitimate heir to the "kludgy" DOS platform.

MS-DOS had grown in spurts, with many significant features being taken or duplicated from Microsoft's other products and operating systems. MS-DOS also grew by incorporating, by direct licensing or feature duplicating, the functionality of tools and utilities developed by independent companies, such as [[Norton Utilities]], [[PC Tools (software)|PC Tools]] ([[MSAV|Microsoft Anti-Virus]]), [[QEMM]] expanded memory manager, [[Lempel–Ziv–Stac|Stacker]] [[disk compression]], and others.

During the period when Digital Research was competing in the operating system market some computers, like the [[Amstrad PC1512]], were sold with floppy disks for two operating systems (only one of which could be used at a time), MS-DOS and CP/M-86 or a derivative of it. Digital Research produced [[DOS Plus]], which was compatible with MS-DOS 2.11, supported CP/M-86 programs, had additional features including multi-tasking, and could read and write disks in CP/M and MS-DOS format.

While OS/2 was under protracted development, Digital Research released the MS-DOS compatible [[DR-DOS]] 5.0, which included features only available as third-party add-ons for MS-DOS. Unwilling to lose any portion of the market, Microsoft responded by announcing the "pending" release of MS-DOS 5.0 in May 1990. This effectively killed most DR DOS sales until the actual release of MS-DOS 5.0 in June 1991. Digital Research brought out DR DOS 6.0, which sold well until the "pre-announcement" of MS-DOS 6.0 again stifled the sales of DR DOS.

Microsoft had been accused of carefully orchestrating leaks about future versions of MS-DOS in an attempt to create what in the industry is called FUD ([[fear, uncertainty, and doubt]]) regarding DR DOS. For example, in October 1990, shortly after the release of DR DOS 5.0, and long before the eventual June 1991 release of MS-DOS 5.0, stories on feature enhancements in MS-DOS started to appear in ''InfoWorld'' and ''PC Week''. [[Brad Silverberg]], then Vice President of Systems Software at Microsoft and general manager of its Windows and MS-DOS Business Unit, wrote a forceful letter to ''PC Week'' (November 5, 1990), denying that Microsoft was engaged in FUD tactics ("to serve our customers better, we decided to be more forthcoming about version 5.0") and denying that Microsoft copied features from DR DOS:

<blockquote>"The feature enhancements of MS-DOS version 5.0 were decided and development was begun long before we heard about DR DOS 5.0. There will be some similar features. With 50 million MS-DOS users, it shouldn't be surprising that DRI has heard some of the same requests from customers that we have."&nbsp;– (Schulman et al. 1994).<ref name="undocumenteddos">{{cite book |author-last1=Schulman |author-first1=Andrew |url=https://archive.org/details/undocumenteddosp00andr_0 |title=Undocumented DOS: A programmer's guide to reserved MS-DOS functions and data structures&nbsp;— expanded to include MS-DOS 6, Novell DOS and Windows 3.1 |author-last2=Brown |author-first2=Ralf D. |author-link2=Ralf D. Brown |author-last3=Maxey |author-first3=David |author-last4=Michels |author-first4=Raymond J. |author-last5=Kyle |author-first5=Jim |date=1994 |publisher=[[Addison Wesley]] |isbn=0-201-63287-X |edition=2 |location=Reading, Massachusetts |orig-year=November 1993<!-- first printing --> |url-access=registration}} (xviii+856+vi pages, 3.5"-floppy) Errata: [https://web.archive.org/web/20190417215556/https://www.cs.cmu.edu/afs/cs/user/ralf/pub/books/UndocumentedDOS/errata.ud2] [https://web.archive.org/web/20190417212906/https://www.pcjs.org/pubs/pc/programming/Undocumented_DOS/#errata-2nd-edition]</ref></blockquote>

The pact between Microsoft and IBM to promote OS/2 began to fall apart in 1990 when [[Windows 3.0]] became a marketplace success. Many of Microsoft's further contributions to OS/2 also went into creating a third [[GUI]] replacement for DOS, [[Windows NT]].

IBM, which had already been developing the next version of OS/2, carried on development of the platform without Microsoft and sold it as the alternative to DOS and Windows.

==Legal issues==
As a response to [[Digital Research]]'s [[DR DOS 6.0]], which bundled SuperStor disk compression, Microsoft opened negotiations with [[Stac Electronics]], vendor of the most popular DOS disk compression tool, Stacker. In the [[due diligence]] process, Stac engineers had shown Microsoft part of the Stacker source code. Stac was unwilling to meet Microsoft's terms for licensing Stacker and withdrew from the negotiations. Microsoft chose to license Vertisoft's DoubleDisk, using it as the core for its DoubleSpace disk compression.<ref>{{Cite news |url=http://www.byte.com/art/9402/sec6/art1.htm |title=How Safe is Disk Compression? |date=February 1994 |work=[[BYTE Magazine]] |archive-url=https://web.archive.org/web/20080619060529/http://www.byte.com/art/9402/sec6/art1.htm |archive-date=June 19, 2008}}</ref>

MS-DOS 6.0 and 6.20 were released in 1993, both including the Microsoft DoubleSpace disk compression utility program. Stac successfully sued Microsoft for patent infringement regarding the compression algorithm used in DoubleSpace. This resulted in the 1994 release of MS-DOS 6.21, which had disk compression removed. Shortly afterwards came version 6.22, with a new version of the disk compression system, DriveSpace, which had a different compression algorithm to avoid the infringing code.

Prior to 1995, Microsoft licensed MS-DOS (and Windows) to computer manufacturers under three types of agreement: per-processor (a fee for each system the company sold), per-system (a fee for each system of a particular model), or per-copy (a fee for each copy of MS-DOS installed). The largest manufacturers used the per-processor arrangement, which had the lowest fee. This arrangement made it expensive for the large manufacturers to migrate to any other operating system, such as DR DOS. In 1991, the U.S. government [[Federal Trade Commission]] began investigating Microsoft's licensing procedures, resulting in a 1994 settlement agreement limiting Microsoft to per-copy licensing. Digital Research did not gain by this settlement, and years later its successor in interest, [[Caldera, Inc.|Caldera]], sued Microsoft for damages in the ''[[Caldera v. Microsoft]]'' lawsuit. It was believed that the settlement ran in the order of {{US$|long=no|150 million}}, but was revealed in November 2009 with the release of the Settlement Agreement to be {{US$|long=no|280 million}}.<ref name="Groklaw_2009_NovellWP">{{Cite web |url=http://www.groklaw.net/article.php?story=20091120165256836 |title=Exhibits to Microsoft's Cross Motion for Summary Judgment in Novell WordPerfect Case |date=November 23, 2009 |website=[[Groklaw]] |access-date=October 22, 2011 |archive-date=August 21, 2013 |archive-url=https://archive.today/20130821080038/http://www.groklaw.net/article.php?story=20091120165256836 |url-status=live }}</ref>

==Use of undocumented APIs==
Microsoft also used a variety of tactics in MS-DOS and several of their applications and development tools that, while operating perfectly when running on genuine MS-DOS (and PC DOS), would break when run on another vendor's implementation of DOS. Notable examples of this practice included:
* [[Microsoft Pascal|Microsoft's QuickPascal]] (released in early 1989) was the first MS product that checked for MS-DOS by modifying the program's [[Program Segment Prefix]] using undocumented DOS functions, and then checked whether or not the associated value changed in a fixed position within the DOS data segment (also undocumented). This check also made it into later MS products, including Microsoft [[QuickC]] v2.5, Programmer's Workbench and Microsoft C v6.0.<ref name="undocumenteddos"/>
* The [[AARD code]], a block of code in the Windows launcher (WIN.COM) and a few other system files of Windows 3.1. It was XOR encrypted, [[Self-modifying code|self-modifying]], and deliberately obfuscated, using various undocumented DOS structures and functions to determine whether or not Windows really was running on MS-DOS.<ref name="undocumenteddos"/> In the beta versions, it displayed an "error" message if the test for genuine MS-DOS failed, prompting the user to abort or continue, with abort the default. In the final release version, the code still ran, but the message and prompt were disabled by an added flag byte, rendering it (probably) ineffectual.
** Windows 3.0 beta release only gave a warning that Windows would not operate properly on a "foreign" OS and actually ran well on DR DOS 6.0.
* Interrupt routines called by Windows to inform MS-DOS that Windows is starting/exiting, information that MS-DOS retained in an IN_WINDOWS flag, in spite of the fact that MS-DOS and Windows were supposed to be two separate products.<ref name="undocumenteddos"/>

==Windows command-line interface==
{{Unreferenced section|date=February 2022}}
[[File:Microsoft Windows 95 Version 4.00.1111 command.com MS-DOS Prompt 492x259.png|thumb|250px|MS-DOS Prompt in [[Windows 95]]]]
[[File:Command Prompt on Windows 10 RTM.png|thumb|250px|Command Prompt in [[Windows 10]]]]
All versions of [[Microsoft Windows]] have had an MS-DOS or MS-DOS-like [[command-line interface]] called [[MS-DOS Prompt]] which redirected input to MS-DOS and output from MS-DOS to the MS-DOS Prompt, or, in later versions, [[Command Prompt]]. This could run many DOS and variously Win32, OS/2 1.x and [[POSIX]] command-line utilities in the same command-line session, allowing piping between commands. The user interface, and the icon up to Windows 2000, followed the native MS-DOS interface. The Command Prompt introduced with Windows NT is not actually MS-DOS, but shares some commands with MS-DOS.

=== Earlier versions of Windows ===
The [[16-bit]] versions of Windows (up to 3.11) ran as a graphical user interface (GUI) on top of MS-DOS. With [[Windows 95]], [[Windows 98|98]], and [[Windows Me|Me]], the role of MS-DOS was reduced to a boot loader according to Microsoft, with MS-DOS programs running in a virtual DOS machine within 32-bit Windows, with ability to boot directly into MS-DOS retained as a backward compatibility option for applications that required real mode access to the hardware, which was generally not possible within Windows.<ref>{{Cite web|date=2007-12-24|title=What was the role of MS-DOS in Windows 95?|url=https://devblogs.microsoft.com/oldnewthing/20071224-00/?p=24063|access-date=2021-06-30|website=The Old New Thing|language=en-US|archive-date=January 28, 2011|archive-url=https://web.archive.org/web/20110128011858/http://blogs.msdn.com/b/oldnewthing/archive/2007/12/24/6849530.aspx|url-status=live}}</ref> The command line accessed the DOS command line (usually <code style="font-family: "Perfect DOS VGA 437,Perfect DOS VGA\ 437,monospace;">COMMAND.COM</code>) through a Windows module (WINOLDAP.MOD).{{clarify|date= August 2015}}

=== Windows NT ===
Windows NT-based operating systems boot to a kernel whose purpose is to load Windows and run the system. One cannot run Win32 applications in the loader system in the manner that OS/2, UNIX or consumer versions of Windows can launch character-mode sessions.

The command session permits running various supported command-line utilities from Win32, MS-DOS, OS/2 1.x and POSIX. The emulators for MS-DOS, OS/2 and POSIX use the host's window in the same way that Win16 applications use the Win32 explorer. Using the host's window allows one to pipe output between emulations.

The MS-DOS emulation takes place through the [[NTVDM]] (NT Virtual DOS Machine). This is a modified [[SoftPC]] (a former product similar to [[VirtualPC]]), running a modified MS-DOS 5 (NTIO.SYS and NTDOS.SYS). The output is handled by the console DLLs, so that the program at the prompt (<code style="font-family: "Perfect DOS VGA 437,Perfect DOS VGA\ 437,monospace;">CMD.EXE</code>, <code style="font-family: "Perfect DOS VGA 437,Perfect DOS VGA\ 437,monospace;">4NT.EXE</code>, <code style="font-family: "Perfect DOS VGA 437,Perfect DOS VGA\ 437,monospace;">TCC.EXE</code>), can see the output. 64-bit Windows has neither the DOS emulation, nor the DOS commands EDIT, [[DEBUG (DOS command)|DEBUG]] and [[EDLIN]] that come with 32-bit Windows.

The DOS version returns 5.00 or 5.50, depending on which API function is used to determine it. Utilities from MS-DOS 5.00 run in this emulation without modification. The very early beta programs of NT show MS-DOS 30.00, but programs running in MS-DOS 30.00 would assume that OS/2 was in control.

The OS/2 emulation is handled through OS2SS.EXE and OS2.EXE, and DOSCALLS.DLL. OS2.EXE is a version of the OS/2 shell (CMD.EXE), which passes commands down to the OS2SS.EXE, and input-output to the Windows NT shell. Windows 2000 was the last version of NT to support OS/2. The emulation is OS/2 1.30.

POSIX is emulated through the POSIX shell, but no emulated shell; the commands are handled directly in CMD.EXE.

The Command Prompt is often called the MS-DOS Prompt. In part, this was the official name for it in Windows 9x and early versions of Windows NT (NT 3.5 and earlier), and in part because the SoftPC emulation of DOS redirects output into it. Actually only <code style="font-family: "Perfect DOS VGA 437,Perfect DOS VGA\ 437,monospace;">COMMAND.COM</code> and other 16-bit commands run in an NTVDM with <code style="font-family: "Perfect DOS VGA 437,Perfect DOS VGA\ 437,monospace;">AUTOEXEC.NT</code> and <code style="font-family: "Perfect DOS VGA 437,Perfect DOS VGA\ 437,monospace;">CONFIG.NT</code> initialization determined by <code style="font-family: "Perfect DOS VGA 437,Perfect DOS VGA\ 437,monospace;">[[Program information file|_DEFAULT.PIF]]</code>, optionally permitting the use of [[Win32 console]] applications and internal commands with an <code style="font-family: "Perfect DOS VGA 437,Perfect DOS VGA\ 437,monospace;">NTCMDPROMPT</code> directive.

[[Win32 console]] applications use <code style="font-family: "Perfect DOS VGA 437,Perfect DOS VGA\ 437,monospace;">CMD.EXE</code> as their command prompt shell. This confusion does not exist under OS/2 because there are separate DOS and OS/2 prompts, and running a DOS program under OS/2 will launch a separate DOS window to run the application.

All versions of Windows for [[Itanium]] (no longer sold by Microsoft) and [[x86-64]] architectures no longer include the NTVDM and can therefore no longer natively run DOS or 16-bit Windows applications. There are alternatives such as [[virtual machine]] emulators such as Microsoft's own [[Virtual PC]], as well as [[VMware]], [[DOSBox]] etc., unofficial compatibility layers such as NTVDMx64, OTVDM (WineVDM), Win3mu and others.

==End-of-life==
[[File:US Navy 110129-N-7676W-152 Culinary Specialist 3rd Class John Smith uses the existing DOS-based food service management system aboard the aircraft.jpg|thumb|{{As of|2011}}, MS-DOS was still used in some enterprises to run [[legacy applications]], such as this [[United States Navy|US Navy]] food service management system.]]
The introduction of [[Windows 3.0]] in 1990, with an easy-to-use [[graphical user interface]], marked the beginning of the end for the command-line driven MS-DOS. With the release of [[Windows 95]] (and continuing in the [[Windows 9x]] product line through to [[Windows Me]]), an integrated version of MS-DOS was used for [[bootstrapping (computing)|bootstrapping]], troubleshooting, and backwards-compatibility with old DOS software, particularly games, and no longer released as a standalone product.<ref name="Goldstein 2017">{{cite news |author-last=Goldstein |author-first=Phil |title=MS-DOS Became Synonymous with PC Operating Systems in the 1980s |url=https://biztechmagazine.com/article/2017/10/ms-dos-became-synonymous-pc-operating-systems-1980s |access-date=January 26, 2018 |publisher=BizTech Magazine |date=October 27, 2017 |archive-url=https://web.archive.org/web/20180126161504/https://biztechmagazine.com/article/2017/10/ms-dos-became-synonymous-pc-operating-systems-1980s |archive-date=January 26, 2018}}</ref> In Windows 95, the DOS, called MS-DOS 7, can be booted separately, without the Windows GUI; this capability was retained through Windows 98 Second Edition. Windows Me removed the capability to boot its underlying MS-DOS 8.0 alone from a hard disk, but retained the ability to make a DOS boot floppy disk (called an "Emergency Boot Disk") and can be hacked to restore full access to the underlying DOS. On December 31, 2001, Microsoft declared all versions of MS-DOS 6.22 and older obsolete and stopped providing support and updates for the system.<ref name="support.microsoft.com">{{cite web |title=Obsolete Products Life-Cycle Policy |date=July 30, 2009 |website=Support |publisher=[[Microsoft]] |url=http://support.microsoft.com/gp/lifeobsoleteproducts |access-date=April 6, 2010 |url-status=dead |archive-url=https://web.archive.org/web/20060706200752/http://support.microsoft.com/gp/lifeobsoleteproducts/ |archive-date=July 6, 2006}}</ref> As MS-DOS 7.0 was a part of Windows 95, support for it also ended when Windows 95 extended support ended on December 31, 2001.<ref name=Lifecycle>{{cite web |title=Microsoft Support Lifecycle |url=http://support.microsoft.com/lifecycle/?p1=7864 |publisher=Microsoft |access-date=February 7, 2015 |archive-date=November 22, 2012 |archive-url=https://web.archive.org/web/20121122121129/http://support.microsoft.com/lifecycle/?p1=7864 |url-status=live }}</ref> As MS-DOS 7.10 and MS-DOS 8.0 were part of Windows 98 and Windows ME, respectively, support ended when Windows 98 and ME extended support ended on July 11, 2006, thus ending support and updates of MS-DOS from Microsoft.<ref name="endofsupport">{{cite web |last1=Montalbano |first1=Elizabeth |title=Microsoft support for Windows 98, ME to end in July |url=https://www.computerworld.com/article/2561853/microsoft-support-for-windows-98--me-to-end-in-july.html |website=Computerworld |access-date=16 February 2021 |language=en |date=13 April 2006 |archive-date=March 29, 2021 |archive-url=https://web.archive.org/web/20210329130119/https://www.computerworld.com/article/2561853/microsoft-support-for-windows-98--me-to-end-in-july.html |url-status=live }}</ref>

In contrast to the Windows 9x series, the [[Windows NT]]-derived 32-bit operating systems ([[Windows NT]], [[Windows 2000|2000]], [[Windows XP|XP]] and newer), developed alongside the 9x series, do not contain MS-DOS compatibility as a core component of the operating system nor do they rely on it for bootstrapping, as NT was not with the level of support for legacy MS-DOS and Win16 apps that Windows 9x was,<ref name="Goldstein 2017"/> but does provide limited DOS emulation called [[Virtual DOS machine#Windows NTVDM|NTVDM]] (NT Virtual DOS Machine) to run DOS applications and provide DOS-like command prompt windows. [[64-bit computing|64-bit]] versions of Windows NT prior to [[Windows 11]] (and [[Windows Server 2008 R2]] by extension) do not provide DOS emulation and cannot run DOS applications natively.<ref>{{Cite web |url=https://support.microsoft.com/en-us/kb/282423 |title=List of limitations in 64-Bit Windows |date=October 11, 2007 |website=Support |publisher=[[Microsoft]] |access-date=May 26, 2016 |archive-date=July 23, 2016 |archive-url=https://web.archive.org/web/20160723055532/https://support.microsoft.com/en-us/kb/282423 |url-status=live }}</ref> [[Windows XP]] onwards contains a copy of the [[Windows Me]] boot disk, stripped down to bootstrap only. This is accessible only by formatting a floppy as an "MS-DOS startup disk". Files like the driver for the CD-ROM support were deleted from the Windows Me bootdisk and the startup files ([[AUTOEXEC.BAT]] and [[CONFIG.SYS]]) no longer had content. This modified disk was the base for creating the MS-DOS image for Windows XP. Some of the deleted files can be recovered with an undelete tool.<ref>{{cite web |author-first=Daniel B. |author-last=Sedory |url=http://thestarman.pcministry.com/winxp/winxpsd.htm |title=Windows XP MS-DOS Startup Disk |work=The Starman's Realm |date=March 9, 2018 |access-date=March 9, 2018 |archive-date=March 9, 2018 |archive-url=https://web.archive.org/web/20180309183210/http://thestarman.pcministry.com/winxp/winxpsd.htm |url-status=live }}</ref> When booting up an MS-DOS startup disk made with the format tool from Windows XP onwards, the version number and the VER internal command reports as "Windows Millennium" and "5.1", respectively, and not as "MS-DOS 8.0" (which was used as the base for Windows Me but never released as a stand-alone product), though the API still says Version 8.0.

The creation of the MS-DOS startup disk was then carried over to later versions of Windows, with the majority of its contents remaining unchanged from its introduction in Windows XP. When creating a DOS startup disk on [[Windows Vista]], the files on the startup disk are dated April 18, 2005, but are otherwise unchanged from XP, including the string "MS-DOS Version 8 Copyright 1981–1999 Microsoft Corp" inside <code>[[COMMAND.COM]]</code>. Windows 7, 8, and 8.1 can also create a MS-DOS startup disk, which are otherwise unchanged from XP and Vista. Starting with [[Windows 10]], the ability to create a MS-DOS startup disk has been removed, and so either a [[virtual machine]] running MS-DOS or an older version (in a virtual machine or dual boot) must be used to format a floppy disk, or an image must be obtained from an external source. Other solutions include using DOS compatible alternatives, such as [[FreeDOS]] or even copying the required files and boot sector themselves. The last remaining components related to MS-DOS was the NTVDM component, which was removed entirely in Windows starting with [[Windows 11]] as the operating system dropped support for 32-bit processors in favor of being solely offered in 64-bit versions only. This effectively ended any association of MS-DOS within Microsoft Windows after 36 years.

MS-DOS 6.22 was the last standalone version produced by Microsoft for [[Intel 8088]], [[Intel 8086]], and [[Intel 80286]] processors, which remains available for download via their [[MSDN]],<ref>{{cite web |title=Supplemental Disk&nbsp;— MS-DOS 6 Technical Reference |date=February 20, 2014 |url=https://msdn.microsoft.com/en-us/library/cc749839.aspx |publisher=Microsoft Developer Network |access-date=January 26, 2018 |archive-url=https://web.archive.org/web/20170902225102/https://msdn.microsoft.com/en-us/library/cc749839.aspx |archive-date=September 2, 2017}}</ref> volume license, and OEM license partner websites, for customers with valid login credentials. MS-DOS is still used in embedded x86 systems due to its simple architecture and minimal memory and processor requirements, though some current products have switched to the still-maintained open-source alternative [[FreeDOS#Commercial uses|FreeDOS]].

In 2018, Microsoft released the [https://github.com/Microsoft/MS-DOS source code for MS-DOS 1.25 and 2.0] on [[GitHub]], with the source code for MS-DOS 4.00 being released in the same repository six years later.<ref name="4.0-mit-relicense"/><ref name=ars-4.0-release/> The purpose of this, according to Microsoft, is mainly for education and experimentation with historic operating systems and for new programmers to gain an understanding of how low-level software works, both historic and current. According to program manager Rich Turner, the other versions could not be open-sourced due to third-party licensing restrictions.<ref>{{Cite web|url=https://github.com/microsoft/MS-DOS/issues/424|title=Where is source code of 3.30 and 5.0 versions? · Issue #424 · microsoft/MS-DOS|website=GitHub|accessdate=March 3, 2021|archive-date=December 19, 2020|archive-url=https://web.archive.org/web/20201219075238/https://github.com/microsoft/MS-DOS/issues/424|url-status=dead}}</ref>

Due to the historical nature of the software, Microsoft will not accept any [[pull request]]s to the code. Users, however, are allowed and fully encouraged to [[Fork (software development)|fork]] the repository containing the MS-DOS source code and make their own modifications, and do whatever they like with it.

==Legacy compatibility==
From 1983 onwards, various companies worked on [[graphical user interface]]s (GUIs) capable of running on PC hardware.<ref>{{Cite web |title=Magic Desk I for Commodore 64 |url=http://toastytech.com/guis/magdesk.html |access-date=2025-06-13 |website=toastytech.com}}</ref> However, this required duplicated effort and did not provide much consistency in interface design (even between products from the same company).{{Cn|date=June 2025}}

Later, in 1985, [[Microsoft Windows 1.0]] was released as Microsoft's first attempt at providing a consistent user interface (for applications). The early versions of Windows ran on top of MS-DOS.<ref>{{Cite book |title=MCSA/MCSE managing and maintaining a Windows server 2003 environment : exam 70-290 study guide and DVD training {{!}} WorldCat.org |oclc=55664320 |language=en}}</ref><ref>{{Cite news |last=Gibbs |first=Samuel |date=2014-10-02 |title=From Windows 1 to Windows 10: 29 years of Windows evolution |url=https://www.theguardian.com/technology/2014/oct/02/from-windows-1-to-windows-10-29-years-of-windows-evolution |access-date=2025-06-13 |work=The Guardian |language=en-GB |issn=0261-3077}}</ref> At first Windows met with little success, but this was also true for most other companies' efforts as well, for example [[Graphics Environment Manager|GEM]]. After version 3.0, Windows gained market acceptance.<ref>{{Cite web |last=Lendino |first=Jamie |date=2015-11-20 |title=Microsoft Windows turns 30: A brief retrospective |url=https://www.extremetech.com/computing/218336-microsoft-windows-turns-30-a-brief-retrospective |access-date=2025-06-13 |website=ExtremeTech |language=en}}</ref>

[[Windows 9x]] used MS-DOS to boot the Windows kernel in protected mode. Basic features related to the file system, such as long file names, were only available to DOS applications when running through Windows.<ref>{{Cite web |last=Chen |first=Raymond |date=2007-12-24 |title=What was the role of MS-DOS in Windows 95? |url=https://devblogs.microsoft.com/oldnewthing/20071224-00/?p=24063 |access-date=2025-06-13 |website=The Old New Thing |language=en-US}}</ref> [[Windows NT]] runs independently of DOS but includes [[NTVDM]], a component for simulating a DOS environment for [[legacy applications]].<ref>{{Cite book |last=Schulman |first=Andrew |url=http://archive.org/details/undocumenteddosp00andr_0 |title=Undocumented DOS : a programmer's guide to reserved MS-DOS functions and data structures |date=1994 |publisher=Reading, Mass. : Addison-Wesley Pub. Co. |others=Internet Archive |isbn=978-0-201-63287-3}}</ref> It was not included with [[Windows 11]] as the operating system is exclusively offered in 64-bit architectures such as x86-64.<ref>{{Cite web |last=Microsoft |title=Windows 11 Specs and System Requirements {{!}} Microsoft Windows |url=https://www.microsoft.com/en-us/windows/windows-11-specifications |access-date=2025-06-13 |website=Windows |language=en-us}}</ref>

==Related systems==
{{main|DOS}}
MS-DOS compatible systems include:
* [[IBM PC DOS]]
* [[DR-DOS]], [[Novell DOS]], [[OpenDOS]]
* [[FreeDOS]]
* [[PTS-DOS]]
* [[ROM-DOS]]

Microsoft made [[IBM PC DOS]] for IBM. It and MS-DOS were identical products that eventually diverged starting with MS-DOS version 6.0. [[Digital Research]] did not follow Microsoft's version numbering scheme. For example, MS-DOS 4, released in July 1988, was followed by DR DOS 5.0 in May 1990. MS-DOS 5.0 came in April 1991, and DR DOS 6.0 was released the following June.<ref>{{Cite web |url=http://oldfiles.org.uk/powerload/timeline.htm |title=DOS Timeline ~ Part One ~ 1980 to 1993 |author-last=Comerford |author-first=M. |website=PowerLoad |archive-url=https://web.archive.org/web/20060224030922/http://oldfiles.org.uk/powerload/timeline.htm |archive-date=February 24, 2006 |access-date=June 18, 2015}}</ref>

These products are collectively referred to as "DOS", even though "Disk Operating System" is a generic term used on other systems unrelated to the x86 and IBM PC. "MS-DOS" can also be a generic reference to DOS on IBM PC compatible computers.

Microsoft's control of the Windows platform, and their programming practices which intentionally made Windows appear as if it ran poorly on competing versions of DOS, crippled the ability of other DOS makers to continue to compete with MS-DOS.<ref name="undocumenteddos"/> Digital Research had to release interim releases to circumvent Windows limitations inserted artificially,<ref name="undocumenteddos"/> designed specifically to provide Microsoft with a competitive advantage.<ref name="undocumenteddos"/>
<!--
==Physical RAM limit==
The maximum physical RAM that MS-DOS 6.22 supports is 64 MB.

==Physical hard disk drive limit==
The maximum capacity of hard disk drive that MS-DOS 6.22 supports is 8.4 GB or 7.84 GiB (8,422,686,720 bytes or 1,024 cylinders x 255 heads per cylinder x 63 sectors per head x 512 bytes per sector).
-->

==See also==
{{portal|Computer programming}}
* {{Annotated link|4DOS}}
* {{Annotated link|Bad command or file name}}
* {{Annotated link|DOSBox}}
* {{Annotated link|DOS memory management}}
* {{Annotated link|History of Microsoft Windows}}
* {{Annotated link|Index of DOS games}}
* {{Annotated link|List of DOS commands}}
* {{Annotated link|OS/2}}
* {{Annotated link|Tao ExDOS}}
* Towns OS – an MS-DOS adaptation for [[FM Towns]]
* {{Annotated link|Win32 console}}

==Notes==
{{reflist|group="nb"}}

==References==
{{reflist|refs=
<ref name="DCP_2016">{{cite web |title=Betriebssystem DCP |author-first1=Rüdiger |author-last1=Kurth |author-first2=Martin |author-last2=Groß |author-first3=Henry |author-last3=Hunger |date=2016-11-29 |orig-year=2007 |language=de |website=www.robotrontechnik.de |url=http://www.robotrontechnik.de/html/software/dcp.htm |access-date=2019-04-28 |url-status=live |archive-url=https://web.archive.org/web/20190403061152/http://www.robotrontechnik.de/html/software/dcp.htm |archive-date=2019-04-03}}</ref>
<ref name="Beley_1986_MS-DOS_Encyclopedia">{{cite book |editor-first1=Jim |editor-last1=Beley |editor-first2=Barry |editor-last2=Preppernau |editor-first3=Pam |editor-last3=Beason |editor-first4=Andrea |editor-last4=Lewis |editor-first5=David |editor-last5=Rygmyr |author-first1=Howard |author-last1=Bornstein |author-first2=Lawrence |author-last2=Bredehoeft |author-first3=Ray |author-last3=Duncan |author-first4=Carol |author-last4=Morris |author-first5=David |author-last5=Rose <!-- |author-link5=David Rose --> |author-first6=John |author-last6=Socha |author-link6=John Socha |author-first7=Jim |author-last7=Tomlin |author-first8=Kathleen |author-last8=Vian |author-first9=Van |author-last9=Wolverton |title=MS-DOS (Versions 1.0-3.2) Technical Reference Encyclopedia |contribution=Technical advisors |contributor-first1=Paul |contributor-last1=Allen |contributor-link1=Paul Allen |contributor-first2=Bill |contributor-last2=Gates |contributor-link2=Bill Gates |contributor-first3=Adrian |contributor-last3=King |contributor-first4=Chris |contributor-last4=Larson |contributor-first5=Gordon |contributor-last5=Letwin |contributor-link5=Gordon Letwin |contributor-first6=Bob |contributor-last6=O'Rear |contributor-link6=Bob O'Rear |contributor-first7=Tim |contributor-last7=Paterson |contributor-link7=Tim Paterson |contributor-first8=Chris |contributor-last8=Peters |contributor-first9=Bruce |contributor-last9=Phillips |contributor-first10=Aaron |contributor-last10=Reynolds |contributor-link10=Aaron R. Reynolds |contributor-first11=Betty |contributor-last11=Stillmaker |contributor-first12=Mark |contributor-last12=Zbikowski |contributor-link12=Mark Zbikowski |date=1986 |edition=Original withdrawn |publisher=[[Microsoft Press]] |series=Microsoft Reference Library |volume=1 |location=Redmond, Washington, USA |isbn=0-914845-69-1 |lccn=86-8640 |oclc=635600205}} (xvii+1053 pages; 29&nbsp;cm) (NB. This original edition contains flowcharts of the internal workings of the system. It was withdrawn by Microsoft before mass-distribution in 1986 because it contained many factual errors as well as some classified information which should not have been published. Few printed copies survived. It was replaced by a completely reworked edition in 1988. [https://blogs.msdn.microsoft.com/larryosterman/2004/06/14/does-anyone-remember-the-original-ms-dos-encyclopedia/] {{Webarchive|url=https://web.archive.org/web/20190715050434/https://blogs.msdn.microsoft.com/larryosterman/2004/06/14/does-anyone-remember-the-original-ms-dos-encyclopedia/ |date=July 15, 2019 }})</ref>
<ref name="Duncan_1988_MS-DOS_Encyclopedia">{{cite book |title=The MS-DOS Encyclopedia: versions 1.0 through 3.2 |author-first1=Ray |author-last1=Duncan |author-first2=Steve |author-last2=Bostwick |author-first3=Keith |author-last3=Burgoyne |author-first4=Robert A. |author-last4=Byers |author-first5=Thom |author-last5=Hogan |author-first6=Jim |author-last6=Kyle |author-first7=Gordon |author-last7=Letwin |author-link7=Gordon Letwin |author-first8=Charles |author-last8=Petzold |author-link8=Charles Petzold |author-first9=Chip |author-last9=Rabinowitz |author-first10=Jim |author-last10=Tomlin |author-first11=Richard |author-last11=Wilton |author-first12=Van |author-last12=Wolverton |author-first13=William |author-last13=Wong |author-first14=JoAnne |author-last14=Woodcock |contribution=Technical advisors |contributor-first1=Mark |contributor-last1=Zbikowski |contributor-link1=Mark Zbikowski |contributor-first2=Paul |contributor-last2=Allen |contributor-link2=Paul Allen |contributor-first3=Steve |contributor-last3=Ballmer |contributor-link3=Steve Ballmer |contributor-first4=Reuben |contributor-last4=Borman |contributor-first5=Rob |contributor-last5=Borman |contributor-first6=John |contributor-last6=Butler |contributor-first7=Chuck |contributor-last7=Carroll |contributor-first8=Mark |contributor-last8=Chamberlain |contributor-first9=David |contributor-last9=Chell |contributor-first10=Mike |contributor-last10=Colee |contributor-first11=Mike |contributor-last11=Courtney |contributor-first12=Mike |contributor-last12=Dryfoos |contributor-first13=Rachel |contributor-last13=Duncan |contributor-first14=Kurt |contributor-last14=Eckhardt |contributor-first15=Eric |contributor-last15=Evans |contributor-first16=Rick |contributor-last16=Farmer |contributor-first17=Bill |contributor-last17=Gates |contributor-link17=Bill Gates |contributor-first18=Michael |contributor-last18=Geary |contributor-first19=Bob |contributor-last19=Griffin |contributor-first20=Doug |contributor-last20=Hogarth |contributor-first21=James W. |contributor-last21=Johnson |contributor-first22=Kaamel |contributor-last22=Kermaani |contributor-first23=Adrian |contributor-last23=King |contributor-first24=Reed |contributor-last24=Koch |contributor-first25=James |contributor-last25=Landowski |contributor-first26=Chris |contributor-last26=Larson |contributor-first27=Thomas |contributor-last27=Lennon |contributor-first28=Dan |contributor-last28=Lipkie |contributor-first29=Marc |contributor-last29=McDonald |contributor-link29=Marc McDonald |contributor-first30=Bruce |contributor-last30=McKinney |contributor-first31=Pascal |contributor-last31=Martin |contributor-first32=Estelle |contributor-last32=Mathers |contributor-first33=Bob |contributor-last33=Matthews <!-- |contributor-link33=Robert Matthews (scientist)??? --> |contributor-first34=David |contributor-last34=Melin |contributor-first35=Charles |contributor-last35=Mergentime |contributor-first36=Randy |contributor-last36=Nevin |contributor-first37=Dan |contributor-last37=Newell |contributor-first38=Tani |contributor-last38=Newell |contributor-first39=David |contributor-last39=Norris |contributor-first40=Mike |contributor-last40=O'Leary |contributor-first41=Bob |contributor-last41=O'Rear |contributor-link41=Bob O'Rear |contributor-first42=Mike |contributor-last42=Olsson |contributor-first43=Larry |contributor-last43=Osterman |contributor-first44=Ridge |contributor-last44=Ostling |contributor-first45=Sunil |contributor-last45=Pai |contributor-first46=Tim |contributor-last46=Paterson |contributor-link46=Tim Paterson |contributor-first47=Gary |contributor-last47=Perez |contributor-first48=Chris |contributor-last48=Peters |contributor-first49=Charles |contributor-last49=Petzold |contributor-link49=Charles Petzold |contributor-first50=John |contributor-last50=Pollock |contributor-first51=Aaron |contributor-last51=Reynolds |contributor-link51=Aaron R. Reynolds |contributor-first52=Darryl |contributor-last52=Rubin |contributor-first53=Ralph |contributor-last53=Ryan |contributor-first54=Karl |contributor-last54=Schulmeisters |contributor-first55=Rajen |contributor-last55=Shah |contributor-first56=Barry |contributor-last56=Shaw |contributor-first57=Anthony |contributor-last57=Short |contributor-first58=Ben |contributor-last58=Slivka |contributor-first59=Jon |contributor-last59=Smirl |contributor-first60=Betty |contributor-last60=Stillmaker |contributor-first61=John |contributor-last61=Stoddard |contributor-first62=Dennis |contributor-last62=Tillman |contributor-first63=Greg |contributor-last63=Whitten |contributor-first64=Natalie |contributor-last64=Yount |contributor-first65=Steve |contributor-last65=Zeck |date=1988 |edition=Completely reworked |publisher=[[Microsoft Press]] |location=Redmond, Washington, USA |isbn=1-55615-049-0 |lccn=87-21452 |oclc=16581341}} (xix+1570 pages; 26&nbsp;cm) (NB. This edition was published in 1988 after extensive rework of the withdrawn 1986 first edition by a different team of authors. [https://www.pcjs.org/pubs/pc/reference/microsoft/mspl13/msdos/encyclopedia/] {{Webarchive|url=https://web.archive.org/web/20181014053041/https://www.pcjs.org/pubs/pc/reference/microsoft/mspl13/msdos/encyclopedia/ |date=October 14, 2018 }})</ref>
}}

==External links==
{{Commons category|MS-DOS}}
* [https://github.com/microsoft/ms-dos MS-DOS Source]{{snd}} MS-DOS 1.25, 2.0, and 4.0 Source Code on GitHub
* [https://web.archive.org/web/20121024151449/http://support.microsoft.com/kb/79747 Current License Agreement Policies for MS-DOS and Windows]
* [http://dosbox.sourceforge.net/news.php?show_news=1 DOSBox, a multiplatform DOS emulator] {{Webarchive|url=https://web.archive.org/web/20071024124942/http://dosbox.sourceforge.net/news.php?show_news=1 |date=October 24, 2007 }}
* [https://archive.org/details/ThesharewareDosCollection Archive MS-DOS Collection]
* [http://www.kompx.com/en/network-setup-in-dos-microsoft-network-client.htm Network setup in MS-DOS - Microsoft Network Client 3.0]

{{Microsoft operating systems}}
{{Disk operating systems}}
{{Microsoft FOSS}}
{{Authority control}}

[[Category:1981 software]]
[[Category:Assembly language software]]
[[Category:Discontinued Microsoft operating systems]]
[[Category:Disk operating systems]]
[[Category:DOS variants]]
[[Category:Floppy disk-based operating systems]]
[[Category:Formerly proprietary software]]
[[Category:Free software operating systems]]
[[Category:Microcomputer software]]
[[Category:Microsoft free software]]
[[Category:Proprietary operating systems]]
[[Category:Software using the MIT license]]
[[Category:Products introduced in 1981]]