Electronic Delay Storage Automatic Calculator ( EDSAC ) was an early British computer.

Later the project was supported by J. Lyons & Co. Ltd., a British firm, who were rewarded with the first commercially applied computer, LEO I, based on the EDSAC design.

As soon as EDSAC was completed, it began serving the University's research needs.

* In the 1960s, EDSAC was used to gather numerical evidence about solutions to elliptic curves, which led to the Birch and Swinnerton-Dyer conjecture.

EDSAC's successor, EDSAC 2, was commissioned in 1958.

In 1961, an EDSAC 2 version of Autocode, an ALGOL-like high-level programming language for scientists and engineers, was developed by David Hartley.

In the mid-1960s, a successor to the EDSAC 2 was planned, but the move was instead made to the Titan, a prototype Atlas 2 — the latter having been developed from the Atlas Computer of the University of Manchester, Ferranti, and Plessey.

Wheeler was a research student at the University Mathematical Laboratory at Cambridge from 1948 – 51, and a pioneer programmer on the EDSAC project.

Hartree and Wilkes estimated that EDSAC was twelve to eighteen months from completion, but said that this timeline could be shortened if additional funding were available.

EDSAC was completed and ran its first program in May 1949.

Its ultrasonic delay line memory based on tanks of mercury, with 2K ( 2048 ) 35-bit words ( i. e., 8¾ K bytes ), was four times as large as that of EDSAC.

It was developed on the EDSAC computer, which uses a cathode ray tube as a visual display to display memory contents.

** LEO I ' Lyons Electronic Office ' was the commercial development of EDSAC computing platform, supported by British firm J. Lyons and Co.

The long-tailed pair was very successfully used in early British computing, most notably the Pilot ACE Model and descendants, Wilkes ' EDSAC, and probably others designed by people who worked with Blumlein or his peers.

In the early 1960s Peter Swinnerton-Dyer used the EDSAC computer at the University of Cambridge Computer Laboratory to calculate the number of points modulo p ( denoted by N < sub > p </ sub >) for a large number of primes p on elliptic curves whose rank was known.

Since his laboratory had its own funding, he was immediately able to start work on a small practical machine, the EDSAC, once back at Cambridge.

This concept was implemented for the first time in EDSAC 2, which also used multiple identical " bit slices " to simplify design.

It was on one of my journeys between the EDSAC room and the punching equipment that ' hesitating at the angles of stairs ' the realization came over me with full force that a good part of the remainder of my life was going to be spent finding errors in my own

At about the same time, EDVAC was under development at the University of Pennsylvania's Moore School of Electrical Engineering, and the University of Cambridge Mathematical Laboratory was working on EDSAC.

It was replaced by EDSAC 2, the first microcoded and bitsliced computer, in 1958.

Titan became fully operational in 1964 and EDSAC 2 was retired the following year.

On May 6, 1949 the EDSAC in Cambridge ran its first program, and due to this event, it is considered " the first complete and fully operational regular electronic digital stored-program computer ".

The Computer Laboratory built and operated the world ’ s first fully operational practical stored program computer ( EDSAC, 1949 ) and offered the world ’ s first taught course in computer science in 1953.

In October 1946, work began under Maurice Wilkes on EDSAC ( Electronic Delay Storage Automatic Calculator ), which subsequently became the world ’ s first fully operational and practical stored program computer when it ran its first program on 6 May 1949.

It was on the boat home that Wilkes planned the original design of EDSAC, which was to become operational in May 1949.

ENIAC administrator and security officer Herman Goldstine distributed copies of this First Draft to a number of government and educational institutions, spurring widespread interest in the construction of a new generation of electronic computing machines, including EDSAC at Cambridge England and SEAC at the U. S. Bureau of Standards.

* EDSAC – world ’ s first practical stored program electronic computer ( 1949 – 1958 )

* May 6 – EDSAC, the first practicable stored-program computer, runs its first program at Cambridge University.

The first configuration interaction calculations were carried out in Cambridge on the EDSAC computer in the 1950s using Gaussian orbitals by Boys and coworkers.

They also learned from Goldstine that, back in the UK, Douglas Hartree and Maurice Wilkes were actually building another such machine, the pioneering EDSAC computer, at the University of Cambridge.

He started his computing career programming the pioneering EDSAC computer, designed and built at Cambridge University.

In 1952, OXO ( or Noughts and Crosses ) for the EDSAC computer became one of the first known video games.

Wilkes received the Turing Award in 1967, with the following citation: " Professor Wilkes is best known as the builder and designer of the EDSAC, the first computer with an internally stored program.

* EDSAC computer, 1949

OXO was a computer game written for the EDSAC computer in 1952, an implementation of the game known as Noughts and Crosses in the UK, or tic-tac-toe in the United States.

OXO did not have widespread popularity because the EDSAC was a computer unique to Cambridge.

This lead to the development of a commercial version of EDSAC developed by Lyons, called LEO, the first computer used for commercial business applications.

* Leslie Treloar, rheologist and expert on rubber, and Maurice Wilkes, creator of the EDSAC computer and inventor of microprogramming, worked at TRE briefly during World War II.

EDSAC ran its first programs on 6 May 1949, when it calculated a table of squares and a list of prime numbers.

In 1953, David Wheeler, returning from a stay at the University of Illinois, designed an index register as an extension to the original EDSAC hardware.

Internally, the EDSAC used two's complement, binary numbers.

There is a simulation of EDSAC available and a full description of the initial orders and first programs.

The machine operators, who were present during the day, selected the next tape from the line and loaded it into EDSAC.

* In 1950, Dr. M. V. Wilkes and Wheeler used EDSAC to solve a differential equation relating to gene frequencies in a paper by Ronald Fisher.

* In 1952, A. S. Douglas developed OXO, a version of noughts and crosses ( tic-tac-toe ) for the EDSAC, with graphical output to a cathode ray tube.

On the 13 January 2011, the Computer Conservation Society announced that it had commissioned a working replica of EDSAC, to be built at The National Museum of Computing ( TNMoC ) in Bletchley Park.

* An EDSAC simulator — Developed by Martin Campbell-Kelly, Department of Computer Science, University of Warwick, England.