thumb|Titan computer, 1965
Titan was the prototype of the Atlas 2 computer developed by Ferranti and the University of Cambridge Mathematical Laboratory in Cambridge, England. It was designed starting in 1963, and in operation from 1964 to 1973.
History
In 1961, the University of Cambridge found itself unable to fund a suitably powerful computer for its needs at the time, so the university purchased from Ferranti the main Atlas processing units and then jointly designed the memory and peripheral equipment.
The Atlas hardware arrived in Cambridge in 1963, although software design was already underway.
Although intended to be more affordable than the Atlas, its price was still over £1 million.
A second Atlas 2 was built in Manchester, and was installed at the Computer-Aided Design Centre (CADCentre) on Madingley Road together with the Cambridge Titan supervisor. This machine, the last Atlas, was finally switched off on 21 December 1976.
A third Atlas 2 was ordered by the UK's Atomic Weapons Research Establishment (AWRE) at Aldermaston. It replaced the faster and much more expensive IBM 7030 Stretch which had been leased from IBM.
Hardware
Titan differed from the original Manchester Atlas by having a real, but cached, main memory, rather than the paged (or virtual) memory used in the Manchester machine. It initially had 28K of memory, but this was expanded first to 64K and later to 128K.
Uses
Titan was the computer on which a team from Ferranti based in Bracknell working with David Barron, David Hartley, Roger Needham and Barry Landy of Cambridge University Maths Lab developed the early multi-user time-sharing operating system called Titan Supervisor. This was arguably the world's first commercially sold time-sharing operating system.