Timeline of DOS operating systems

Also presented is a timeline of events in the history of the 8-bit 8080-based and 16-bit x86-based CP/M operating systems from 1974 to 2014, as well as the hardware and software developments from 1973 to 1995 which formed the foundation for the initial version and subsequent enhanced versions of these operating systems.

DOS releases have been in the forms of:

• OEM adaptation kits (OAKs) – all Microsoft releases before version 3.2 were OAKs only
• Shrink wrap packaged product for smaller OEMs (system builders) – starting with MS-DOS 3.2 in 1986,
  Microsoft offered these in addition to OAKs
• End-user retail – all versions of IBM PC DOS (and other OEM-adapted versions) were sold to end users.
  DR-DOS began selling to end users with version 5.0 in July 1990, followed by MS-DOS 5.0 in June 1991
• Free download – starting with OpenDOS 7.01 in 1997, followed by FreeDOS alpha 0.05 in 1998
  (FreeDOS project was announced in 1994)

DOS era version overview (1980–1995)