Atlas (computer)

Atlas

The University of Manchester Atlas in January 1963
Product family	Manchester computers
Release date	1962
Units sold	3 (+ 3 Atlas 2)

The Atlas was one of the world's first supercomputers, in use from 1962 (when it was claimed to be the most powerful computer in the world) to 1972.^[1] Atlas's capacity promoted the saying that when it went offline, half of the United Kingdom's computer capacity was lost.^[2] It is notable for being the first machine with virtual memory (at that time referred to as "one-level store"^[3]) using paging techniques; this approach quickly spread, and is now ubiquitous.

Atlas was a second-generation computer, using discrete germanium transistors. Atlas was created in a joint development effort among the University of Manchester, Ferranti and Plessey. Two other Atlas machines were built: one for BP and the University of London, and one for the Atlas Computer Laboratory at Chilton near Oxford.

A derivative system was built by Ferranti for the University of Cambridge. Called the Titan, or Atlas 2,^[4] it had a different memory organisation and ran a time-sharing operating system developed by Cambridge University Computer Laboratory. Two further Atlas 2s were delivered: one to the CAD Centre in Cambridge (later called CADCentre, then AVEVA), and the other to the Atomic Weapons Research Establishment (AWRE), Aldermaston.

The University of Manchester's Atlas was decommissioned in 1971.^[5] The final Atlas, the CADCentre machine, was switched off in late 1976.^[6] Parts of the Chilton Atlas are preserved by National Museums Scotland in Edinburgh; the main console itself was rediscovered in July 2014 and is at Rutherford Appleton Laboratory in Chilton, near Oxford.