Disk Operating System - Disk Operating Systems That Were The Main OS

Disk Operating Systems That Were The Main OS

Some disk operating systems were the operating system for the entire computer system.

• The DOS/360 initial/simple operating system for the IBM System/360 family of mainframe computers (it later became DOS/VSE, and was eventually just called VSE).
• The DOS operating system for DEC PDP-11 minicomputers. This OS and the computers it ran on were nearly obsolete by the time PCs became common, with various descendants and other replacements.
• DOS for the IBM PC compatible platform

The best known family of operating systems named "DOS" is that running on IBM PCs type hardware using Intel x86 CPUs or their compatible cousins from other makers. Any DOS in this family is usually just referred to as DOS. The original was 86-DOS, which would later become Microsoft MS-DOS. It was also licensed to IBM by Microsoft, and marketed by them as PC-DOS. Digital Research produced a compatible variant known as DR DOS, which was eventually taken over (after a buyout of Digital Research) by Novell, then by Caldera. This became Novell DOS, then the open source OpenDOS, before being changed back to DR-DOS. There is also a free and open source version named FreeDOS.