There were other DOSs, but even by 1989 the use of unqualified "DOS" was usually taken to mean "IBM-compatible PC running MS-DOS" (eg. "Our school has both Appl

There were other DOSs, but even by 1989 the use of unqualified "DOS" was usually taken to mean "IBM-compatible PC running MS-DOS" (eg. "Our school has both Apple and DOS computers in the library").