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CP/CMS (''Control Program/Cambridge Monitor System'') was a time-sharing operating system of the late 60s and early 70s, known for its excellent performance and advanced features.〔Stuart E. Madnick (1969) (【引用サイトリンク】 title=Time-Sharing Systems: Virtual Machine Concept vs. Conventional Approach ) Modern Data Systems, Vol. 2, No. 3, pp. 34-36.〕〔Stuart Madnick (1976) (【引用サイトリンク】 title=Virtual Machine Advantages in Security, Integrity, and Decision Support Systems ) IBM Systems Journal, Vol. 15, No. 3.〕 It had three distinct versions: * CP-40/CMS, an important "one-off" research system that established the CP/CMS virtual machine architecture * CP-67/CMS, a reimplementation of CP-40/CMS for the IBM System/360-67, and the primary focus of this article * CP-370/CMS, a reimplementation of CP-67/CMS for the System/370 – never released as such, but became the foundation of IBM's 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 M44/44X (which used partial virtualization) and 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. == Overview == CP/CMS was built by IBM's Cambridge Scientific Center (CSC), a research and development lab with ties to MIT, under the leadership of Robert Creasy. The system's goals, development process, release, and legacy of breakthrough technology, set this system apart from other OSes of its day and from other large IBM projects. It was an open-source system, made available in source code form to all IBM customers at no charge – as part of the unsupported IBM Type-III Library. CP/CMS users supported themselves and each other. Unusual circumstances, described in the History section below, led to this situation. CP/CMS consisted of two main components: * CP, the ''Control Program'', created the virtual machine environment. The widely used version was CP-67, ran on the S/360-67. (The research system CP-40 established the architecture. A third version, CP-370, became VM/370.) Instead of explicitly dividing up memory and other resources among users, which had been the traditional approach, CP provided each user with a simulated stand-alone System/360 computer. Each system able to run any S/360 software that ran on the bare machine and in effect gave each user a private computer system. * CMS, the ''Cambridge Monitor System'' (and also ''Console Monitor System''〔Creasy, ''op. cit., p.'' 488 – "Console Monitor System"〕 – but renamed Conversational Monitor System in VM) was a lightweight single-user operating system, for interactive time-sharing use. By running many copies of CMS in CP's virtual machines – instead of multiple copies of large, traditional multi-tasking OS – the overhead per user was less. This allowed a great number of simultaneous users to share a single S/360. The CP/CMS virtual machine concept was an important step forward in operating system design. * By isolating users from each other, CP/CMS greatly improved system reliability and security. * By simulating a full, stand-alone computer for each user, CP/CMS could run ''any'' S/360 software in a time-sharing environment, not just applications specifically designed for time-sharing. * By using lightweight CMS as the primary user interface, CP/CMS achieved unprecedented time-sharing performance. In addition, the simplicity of CMS made it easier to implement user interface enhancements than in traditional OS. IBM reimplemented CP/CMS as its VM/370 product line, released in 1972 when virtual memory was added to the S/370 series. VM/370's successors (such as z/VM) remain in wide use today. (It is important to note that IBM ''reimplemented'' CP-67, as it had CP-40, and did not simply rename and repackage it. VM coexisted with CP/CMS and its successors for many years. It is thus appropriate to view CP/CMS as an independent OS, distinct from the VM family.) CP/CMS was viewed as "IBM's ''other'' operating system", a poor cousin to IBM's recommended batch-oriented offerings. Until recently, VM retained this role. But CP/CMS rose above limited resources and company politics, to create an enduring and important technical legacy, a fiercely loyal user base, major derivative systems in the time-sharing industry, and, ultimately, a heritage as the grandparent of major 21st century products from IBM. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「CP/CMS」の詳細全文を読む スポンサード リンク
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