Editing CP/CMS (section)

{{short description|IBM operating system specializing in virtualization}}
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{{tone|date=April 2016}}
{{Citation style|date=April 2015}}
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{{Infobox OS
| name                   = CP/CMS
| logo                   = IBM logo.svg
| logo size              = 120px
| screenshot             =
| caption                =
| developer              = [[IBM]] [[Cambridge Scientific Center]]
| source_model           = Source code (see text for details)
| kernel_type            =
| supported_platforms    = [[IBM System/360-67]]; also [[System/370]] with virtual memory hardware (not present in original S/370 models); also used on experimental hardware
| ui                     = [[Command-line interface]]
| family                 = [[VM (operating system)|VM]]
| released               = {{Start date and age|1968|05}}
| latest_release_version = 3.2
| latest_release_date    = {{Start date and age|1972}}
| latest_test_version    =
| latest_test_date       =
| marketing_target       =
| programmed_in          = [[IBM Basic Assembly Language and successors#Assembler E and F|Assembler (F)]]
| prog_language          =
| language               = [[English language|English]]
| updatemodel            =
| package_manager        =
| working_state          = Historic
| license                = [[IBM Type-III Library]] (free in source code form at no charge to IBM customers, without support)
| website                =
}}

'''CP/CMS''' ('''Control Program/Cambridge Monitor System''') is a discontinued [[time-sharing]] [[operating system]] of the late 1960s and early 1970s. It is known for its excellent performance and advanced features.<ref>Stuart E. Madnick (1969) {{cite web|url=http://web.mit.edu/smadnick/www/papers/J004.pdf | title=Time-Sharing Systems: Virtual Machine Concept vs. Conventional Approach | access-date=2012-09-13}} Modern Data Systems, Vol. 2, No. 3, pp. 34-36.</ref><ref>Stuart Madnick (1976) {{cite web|url=http://web.mit.edu/smadnick/www/papers/J009.pdf | title=Virtual Machine Advantages in Security, Integrity, and Decision Support Systems | access-date=2012-09-13}} [[IBM]] Systems Journal, Vol. 15, No. 3.</ref> Among its three versions, [[IBM CP-40|CP-40]]/CMS was an important 'one-off' research system that established the CP/CMS [[virtual machine]] architecture. It was followed by [[CP-67]]/CMS, a reimplementation of CP-40/CMS for the [[IBM System/360-67]], and the primary focus of this article. Finally, [[CP-370]]/CMS was a reimplementation of CP-67/CMS for the [[System/370]]. While it was never released as such, it became the foundation of [[IBM]]'s [[VM (operating system)|VM/370]] operating system, announced in 1972.

Each implementation was a substantial redesign of its predecessor and an evolutionary step forward.     CP-67/CMS was the first widely available virtual machine architecture. IBM pioneered this idea with its research systems [[IBM M44/44X|M44/44X]] (which used [[partial virtualization]]) and [[IBM CP-40|CP-40]] (which used [[full virtualization]]).

In addition to its role as the predecessor of the VM family, CP/CMS played an important role in the development of [[operating system]] (OS) theory, the design of [[IBM]]'s System/370, the [[time-sharing]] industry, and the creation of a self-supporting user community that anticipated today's [[free software movement]].