IBM CP-40

CP-40CP-40/CMS
CP-40 was a research precursor to CP-67, which in turn was part of IBM's then-revolutionary [[CP/CMS|CP[-67]/CMS]] – a virtual machine/virtual memory time-sharing operating system for the IBM System/360 Model 67, and the parent of IBM's VM family.wikipedia
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CP/CMS

CP-40 CP[-67]/CMSCMS
CP-40 was a research precursor to CP-67, which in turn was part of IBM's then-revolutionary [[CP/CMS|CP[-67]/CMS]] – a virtual machine/virtual memory time-sharing operating system for the IBM System/360 Model 67, and the parent of IBM's VM family.
IBM pioneered this idea with its research systems M44/44X (which used partial virtualization) and CP-40 (which used full virtualization).

CP-67

CP-40 was a research precursor to CP-67, which in turn was part of IBM's then-revolutionary [[CP/CMS|CP[-67]/CMS]] – a virtual machine/virtual memory time-sharing operating system for the IBM System/360 Model 67, and the parent of IBM's VM family.
It was a reimplementation of their earlier research system CP-40, which ran on a one-off customized S/360-40.

Conversational Monitor System

CMSVM/CMSCambridge Monitor System
CP-40 ran multiple instances of client operating systems – particularly CMS, the Cambridge Monitor System, built as part of the same effort.
Through all its distinct versions and releases, the CMS platform remained still quite recognizable as a close descendant of the original CMS version running under CP-40.

Virtual machine

virtual machinesVMvirtual server
CP-40 was a research precursor to CP-67, which in turn was part of IBM's then-revolutionary [[CP/CMS|CP[-67]/CMS]] – a virtual machine/virtual memory time-sharing operating system for the IBM System/360 Model 67, and the parent of IBM's VM family.
This evolved into virtual machines, notably via IBM's research systems: the M44/44X, which used partial virtualization, and the CP-40 and SIMMON, which used full virtualization, and were early examples of hypervisors.

VM (operating system)

VM/CMSVMVM/370
CP-40 was a research precursor to CP-67, which in turn was part of IBM's then-revolutionary [[CP/CMS|CP[-67]/CMS]] – a virtual machine/virtual memory time-sharing operating system for the IBM System/360 Model 67, and the parent of IBM's VM family.
VM-CP began life as CP-370, a reimplementation of CP-67, itself a reimplementation of CP-40.

Time-sharing

timesharingtime sharingtime-sharing system
CP-40 was a research precursor to CP-67, which in turn was part of IBM's then-revolutionary [[CP/CMS|CP[-67]/CMS]] – a virtual machine/virtual memory time-sharing operating system for the IBM System/360 Model 67, and the parent of IBM's VM family.

Full virtualization

virtualization
These changes gave the unit the technology needed for full virtualization of the System/360 hardware.
It was first demonstrated with IBM's CP-40 research system in 1967, then distributed via open source in CP/CMS in 1967–1972, and re-implemented in IBM's VM family from 1972 to the present.

History of CP/CMS

time-sharing operating systems
Also see History of CP/CMS for additional context.
Robert Creasy left Project MAC to lead the CSC team, which promptly began work on what was to become CP-40, the first successful virtual machine operating system based on fully virtualized hardware.

IBM M44/44X

M44/44X
The term virtual machine probably originated with the M44/44X project, from which it was later appropriated by the CP-40 team to replace their earlier term pseudo machine.

Virtual memory

virtual storagememoryswap
CP-40 was a research precursor to CP-67, which in turn was part of IBM's then-revolutionary [[CP/CMS|CP[-67]/CMS]] – a virtual machine/virtual memory time-sharing operating system for the IBM System/360 Model 67, and the parent of IBM's VM family.

Operating system

operating systemsOScomputer operating system
CP-40 was a research precursor to CP-67, which in turn was part of IBM's then-revolutionary [[CP/CMS|CP[-67]/CMS]] – a virtual machine/virtual memory time-sharing operating system for the IBM System/360 Model 67, and the parent of IBM's VM family.

IBM System/360 Model 67

IBM System/360-67System/360 Model 67Model 67
CP-40 was a research precursor to CP-67, which in turn was part of IBM's then-revolutionary [[CP/CMS|CP[-67]/CMS]] – a virtual machine/virtual memory time-sharing operating system for the IBM System/360 Model 67, and the parent of IBM's VM family.

Cambridge Scientific Center

IBM's Cambridge Scientific CenterIBM Cambridge Scientific Center
Like CP-67, CP-40 and the first version of CMS were developed by IBM's Cambridge Scientific Center (CSC) staff, working closely with MIT researchers at Project MAC and Lincoln Laboratory.

MIT Computer Science and Artificial Intelligence Laboratory

Project MACMIT Artificial Intelligence LaboratoryComputer Science and Artificial Intelligence Laboratory
Like CP-67, CP-40 and the first version of CMS were developed by IBM's Cambridge Scientific Center (CSC) staff, working closely with MIT researchers at Project MAC and Lincoln Laboratory.

MIT Lincoln Laboratory

Lincoln LaboratoryLincoln Laboratory's Experimental Test SiteLincoln Lab's ETS
Like CP-67, CP-40 and the first version of CMS were developed by IBM's Cambridge Scientific Center (CSC) staff, working closely with MIT researchers at Project MAC and Lincoln Laboratory.

IBM System/360 Model 40

Model 40360/4040
CP-40 ran on a unique, specially modified IBM System/360 Model 40.

Multics

Multics operating systemMultics project
However, the project became embroiled in an internal IBM political war over time-sharing versus batch processing; and it failed to win the hearts and minds of the academic computer science community, which ultimately turned away from IBM to systems like Multics, UNIX, TENEX, and various DEC operating systems.

Unix

UNIX operating systemAT&T UnixUnix-like
However, the project became embroiled in an internal IBM political war over time-sharing versus batch processing; and it failed to win the hearts and minds of the academic computer science community, which ultimately turned away from IBM to systems like Multics, UNIX, TENEX, and various DEC operating systems.

TENEX (operating system)

TENEXTENEX operating system
However, the project became embroiled in an internal IBM political war over time-sharing versus batch processing; and it failed to win the hearts and minds of the academic computer science community, which ultimately turned away from IBM to systems like Multics, UNIX, TENEX, and various DEC operating systems.

Digital Equipment Corporation

DECDigitalDigital Equipment
However, the project became embroiled in an internal IBM political war over time-sharing versus batch processing; and it failed to win the hearts and minds of the academic computer science community, which ultimately turned away from IBM to systems like Multics, UNIX, TENEX, and various DEC operating systems.

Page fault

invalid page faultpage faultsmemory exception
Similarly, references to virtual memory locations not present in main memory cause page faults, which again were handled by control program rather than reflected to the virtual machine.

Bell Labs

Bell LaboratoriesBell Telephone LaboratoriesAT&T Bell Laboratories
This modified Model 40 influenced the design of the forthcoming Model 67, which was intended to meet the needs of the same community of time-sharing users (notably MIT's Project MAC and Bell Laboratories – though both of these sites became notable IBM sales failures).