IBM PC DOS
discontinued computer operating system
IBM PC DOS (an acronym for IBM Personal Computer Disk Operating System), also known as IBM DOS or PC DOS, is a discontinued disk operating system for the IBM Personal Computer, its successors, and IBM PC compatibles. It was sold by IBM from the early 1980s into the 2000s. Developed by Microsoft, it was also sold by that company to the open market as MS-DOS. Both operating systems were identical or almost identical until 1993, when IBM began selling PC DOS 6.1 with its own new features. The collective shorthand for PC DOS and MS-DOS was DOS, which is also the generic term for disk operating system, and is shared with dozens of disk operating systems called DOS.
History
The IBM task force assembled to develop the IBM PC decided that critical components of the machine, including the operating system, would come from outside vendors. This radical break from company tradition of in-house development was one of the key decisions that made the IBM PC an industry standard. Microsoft, founded five years earlier by Bill Gates, was eventually selected for the operating system.
IBM wanted Microsoft to retain ownership of whatever software it developed, and wanted nothing to do with helping Microsoft, other than making suggestions from afar. According to task force member Jack Sams:
The reasons were internal. We had a terrible problem being sued by people claiming we had stolen their stuff. It could be horribly expensive for us to have our programmers look at code that belonged to someone else because they would then come back and say we stole it and made all this money.
This brief starts where responsible research should: with the source description of “IBM PC DOS” as discontinued computer operating system. Everything that follows is an evidence route, not borrowed authority.
Why this record matters
The subject matters to the general reference register because the source frames it as discontinued computer operating system. Its deeper value depends on whether names, dates, institutions and citations support that framing.
Vocabulary and entity names are the principal evidence signals here, because they determine the precision of every later search. The source revision retrieved here is dated Jul 27, 2026. The linked authority identifier is Q863568. VIAF identifies the subject as 183952118. The Library of Congress control number is n91038175. 1 of 4 selected statements include explicit references; 0 carry qualifiers and 0 use preferred rank. The first chronological checks are 1993.
Overview language is designed for orientation and should not be treated as a substitute for the evidence cited beneath it. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.
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This entry incorporates text from “IBM PC DOS” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.