Note: This timeline is missing data for important historical systems, including: Atlas Computer (Manchester), GE 645, Burroughs B5000.
In the mid-1960s, IBM's Cambridge Scientific Center develops CP-40, the first version of CP/CMS.
Experience on the CP-40 project provides input to the development of the IBM System/360 Model 67, announced in 1965.
In 1972, IBM announces that virtual memory would be made available on all S/370 models, and also announces several virtual storage operating systems, including VM/370.
By the mid-1970s, CP/CMS, VM, and VP/CSS are running on numerous large IBM mainframes.