<Tr> <Th_colspan="2"> Support status </Th> </Tr> <Tr> <Td_colspan="2"> Unsupported as of December 31, 2001 </Td> </Tr> <P> MS - DOS (/ ˌɛmˌɛsˈdɒs / em - ess - DOSS; acronym for Microsoft Disk Operating System) is an operating system for x86 - based personal computers mostly developed by Microsoft . Collectively, MS - DOS, its rebranding as IBM PC DOS, and some 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 personal computers during the 1980s and the early 1990s, when it was gradually superseded by operating systems offering a graphical user interface (GUI), in various generations of the graphical Microsoft Windows operating system . </P> <P> MS - DOS resulted from a request in 1981 by IBM for an operating system to use in its IBM PC range of personal computers . Microsoft quickly bought the rights to 86 - DOS from Seattle Computer Products, and began work on modifying it to meet IBM's specification . IBM licensed and released it on August 12, 1981 as PC DOS 1.0 for use in their PCs . Although MS - DOS and PC 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 . </P>

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