Cray Operating System

Cray Operating System
DeveloperCray Research[1]
Working stateDiscontinued
Initial release1975; 49 years ago (1975)[1]
Latest release1.17.2 / July 1990; 34 years ago (1990-07)
Marketing targetSupercomputers
Available inEnglish
PlatformsCray-1, Cray X-MP line
Influenced byCDC SCOPE
LicenseProprietary
Preceded byChippewa Operating System
Succeeded byUNICOS

The Cray Operating System (COS) is a Cray Research operating system for its now-discontinued Cray-1 (1976) and Cray X-MP supercomputers. It succeeded the Chippewa Operating System (shipped with earlier Control Data Corporation CDC 6000 series and 7600 computer systems), and was the Cray main OS until replaced by UNICOS in the late 1980s. COS was delivered with Cray Assembly Language (CAL), Cray FORTRAN (CFT), and Pascal.