CP/CMS

CP/CMS
DeveloperIBM Cambridge Scientific Center
Written inAssembler (F)
OS familyVM
Working stateHistoric
Source modelSource code (see text for details)
Initial releaseMay 1968; 56 years ago (1968-05)
Latest release3.2 / 1972; 52 years ago (1972)
Available inEnglish
PlatformsIBM System/360-67; also System/370 with virtual memory hardware (not present in original S/370 models); also used on experimental hardware
Default
user interface
Command-line interface
LicenseIBM Type-III Library (free in source code form at no charge to IBM customers, without support)

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.[1][2] Among its three versions, 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/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.

  1. ^ Stuart E. Madnick (1969) "Time-Sharing Systems: Virtual Machine Concept vs. Conventional Approach" (PDF). Retrieved 2012-09-13. Modern Data Systems, Vol. 2, No. 3, pp. 34-36.
  2. ^ Stuart Madnick (1976) "Virtual Machine Advantages in Security, Integrity, and Decision Support Systems" (PDF). Retrieved 2012-09-13. IBM Systems Journal, Vol. 15, No. 3.