Chippewa Operating System

{{Short description|Computer operating system for 1960s-era mainframes}}

{{Infobox OS

| name = Chippewa Operating System (COS)

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| screenshot = CDC 6600 introduced in 1964.jpg

| caption = CDC 6600 with the system console

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| developer = Control Data Corporation

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| working state = Discontinued

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| marketing target = Supercomputers

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| supported platforms = CDC 6600 supercomputer

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| influenced = CDC Kronos, CDC SCOPE

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| license = Proprietary

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| succeeded by = CDC SCOPE

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The Chippewa Operating System (COS) is a discontinued operating system developed by Control Data Corporation in 1964{{cite web |url=https://www.computerhistory.org/collections/catalog/102710088 |title=6600 - CHIPPEWA operating system (Artifact Details) |last= |first= |date=1964 |website=Computer History Museum |access-date=2023-12-23}} for the CDC 6600, generally considered the first supercomputer in the world.{{cite book |title=History of Computing in Education |editor1-first=John |editor1-last=Impagliazzo |editor2-first=John |editor2-last=Lee |series=IFIP Advances in Information and Communication Technology |publisher=Springer |year=2004 |isbn=1-4020-8135-9 |page=172}} The Chippewa was initially developed as an experimental system, but was then also deployed on other CDC 6000 machines.{{cite book |title=Design of a Computer: The Control Data 6600 |first=James E. |last=Thornton |publisher=Scott, Foresman and Company |year=1970 |isbn=0-673-05953-7 |page=163}}

The Chippewa was a rather simple job control oriented system derived from the earlier CDC 3000. Its design influenced the later CDC Kronos and SCOPE operating systems.{{cite book |title=The Computer Revolution in Canada: Building National Technological Competence |first=John N. |last=Vardalas |series=History of Computing |publisher=The MIT Press |year=2001 |isbn=0-262-22064-4 |page=258}} Its name was based on the Chippewa Falls research and development center of CDC in Wisconsin.

It is distinct from and preceded the Cray Operating System (also called "COS") at Cray.