operating system

operating system: n.  [techspeak] (Often abbreviated `OS')
   The foundation software of a machine, of course; that which
   schedules tasks, allocates storage, and presents a default
   interface to the user between applications.  The facilities an
   operating system provides and its general design philosophy exert
   an extremely strong influence on programming style and on the
   technical cultures that grow up around its host machines.  Hacker
   folklore has been shaped primarily by the {{UNIX}}, {{ITS}},
   {{TOPS-10}}, {{TOPS-20}}/{{TWENEX}}, {{WAITS}}, {{CP/M}},
   {{MS-DOS}}, and {{Multics}} operating systems (most importantly
   by ITS and UNIX).