Editing Cray Operating System (section)

{{Short description|System software for supercomputers}}
{{Refimprove|date=December 2009}}
{{Infobox OS
| logo                   =
| screenshot             =
| caption                =
| developer              = [[Cray Research]]<ref name=cosmanual1981>[https://bitsavers.trailing-edge.com/pdf/cray/COS/T-0103C-CRAY_1_Computer_System-Operating_System_COS_Workbook-Training-September_1981.OCR.pdf T-0103C-CRAY_1_Computer_System-Operating_System_COS_Workbook-Training-15th September_1981]</ref>
| family                 =
| source_model           =
| working_state          = Discontinued
| released               = {{Start date and age|1975}}<ref name=cosmanual1981 />
| latest_release_version = 1.17.2
| latest_release_date    = {{Start date and age|1990|07}}
| marketing_target       = [[Supercomputer]]s
| language               = [[English language|English]]
| supported_platforms    = [[Cray-1]], [[Cray X-MP]] line
| kernel_type            =
| influenced_by          = [[CDC SCOPE]]
| license                = [[Proprietary software|Proprietary]]
| preceded by            = [[Chippewa Operating System]]
| succeeded by           = [[UNICOS]]
| website                =
}}
The '''Cray Operating System''' ('''COS''') is a [[Cray Research]] [[operating system]] for its now-discontinued [[Cray-1]] (1976) and [[Cray X-MP]] [[supercomputer]]s. It succeeded the [[Chippewa Operating System]] (shipped with earlier [[Control Data Corporation]] CDC [[CDC 6000 series|6000 series]] and [[CDC 7600|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 (programming language)|Pascal]].