CP-67 was the control program portion of CP/CMS

CP/CMS

CP/CMS was a time-sharing operating system of the late 60s and early 70s, known for its excellent performance and advanced features...

, a virtual machine

Virtual machine

A virtual machine is a "completely isolated guest operating system installation within a normal host operating system". Modern virtual machines are implemented with either software emulation or hardware virtualization or both together.-VM Definitions:A virtual machine is a software...

 operating system developed for the IBM System/360-67 by IBM's Cambridge Scientific Center

Cambridge Scientific Center

The IBM Cambridge Scientific Center, established in February 1964 by Norm Rasmussen, was situated at 545 Technology Square , Cambridge, Massachusetts in the same building as MIT's Project MAC...

. It was a reimplementation of their earlier research system CP-40

IBM CP-40

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

, which ran on a one-off customized S/360-40. CP-67 was later reimplemented (again) as CP-370

CP-370

CP-370 was a re-implementation of CP-67 for the IBM System/370. This was made possible when IBM added virtual memory to the System/370 series, which was announced in 1972 along with IBM's VM/370 system. At release, CP-370 was renamed VM-CP. A successor of this software is found in today's z/VM. See...

, which IBM released as VM/370

VM (operating system)

VM refers to a family of IBM virtual machine operating systems used on IBM mainframes System/370, System/390, zSeries, System z and compatible systems, including the Hercules emulator for personal computers. The first version, released in 1972, was VM/370, or officially Virtual Machine Facility/370...

 in 1972, when virtual memory

Virtual memory

In computing, virtual memory is a memory management technique developed for multitasking kernels. This technique virtualizes a computer architecture's various forms of computer data storage , allowing a program to be designed as though there is only one kind of memory, "virtual" memory, which...

 was added to the System/370

System/370

The IBM System/370 was a model range of IBM mainframes announced on June 30, 1970 as the successors to the System/360 family. The series maintained backward compatibility with the S/360, allowing an easy migration path for customers; this, plus improved performance, were the dominant themes of the...

 series. Details on the development and circumstances of CP-67 can be found in the article History of CP/CMS

History of CP/CMS

This article covers the History of CP/CMS — the historical context in which this important IBM time-sharing virtual machine operating system was built. It provides details to support the main CP/CMS and History of IBM articles, drawing on source material that is not readily available on-line.CP/CMS...

.