This is a list of disk operating systems with the acronym DOS as part of the name (e.g., TRSDOS for the TRS-80 line of computers). Many are (or were in the day) called simply DOS within the context of their respective user communities. In the case of MS-DOS, its ubiquitiousness as the operating system for IBM PC compatibles, prior to Windows 95, caused DOS to be widely used as a synonym for MS-DOS.
DOS variants targeted for an IBM PC compatible computer (in chronological order of first release):