EDSAC

Electronic Delay Storage Automatic Calculator (EDSAC)
EDSAC I in June 1948
DeveloperMaurice Wilkes and his team at the University of Cambridge Mathematical Laboratory
ManufacturerUniversity of Cambridge
Generation1
Release date6 May 1949 (1949-05-06)
Lifespan1949–1958
Discontinuedyes
Units shipped1
Operating systemNone
CPUDerated thermionic valves
Memory512 17-bit words, upgraded in 1952 to 1024 17-bit words (temperature-stabilized mercury delay lines)
DisplayTeleprinter
Inputfive-hole punched tape
Power11 kW
Backward
compatibility
None
SuccessorEDSAC 2 and LEO I
RelatedEDVAC

The Electronic Delay Storage Automatic Calculator (EDSAC) was an early British computer. Inspired by John von Neumann's seminal First Draft of a Report on the EDVAC, the machine was constructed by Maurice Wilkes and his team at the University of Cambridge Mathematical Laboratory in England to provide a service to the university. EDSAC was the second electronic digital stored-program computer, after the Manchester Mark 1, to go into regular service.

Later the project was supported by J. Lyons & Co. Ltd., intending to develop a commercially applied computer and resulting in Lyons' development of the LEO I, based on the EDSAC design. Work on EDSAC started during 1947, and it ran its first programs on 6 May 1949, when it calculated a table of square numbers and a list of prime numbers. EDSAC was finally shut down on 11 July 1958, having been superseded by EDSAC 2, which remained in use until 1965.