EDSAC runs its first program

6th May 1949
EDSAC runs its first program

The Electronic Delay Storage Automatic Calculator (EDSAC) was the first practical stored-program computer to operate a regular computing service.

EDSAC was built by Maurice Wilkes at the University of Cambridge Mathematical Laboratory.

On 6th May 1949, EDSAC performed its first calculation, running a program written by Beatrice Worsley to calculate the squares of numbers.

J. Lyons & Co. Ltd., a British firm, helped fund the EDSAC project with a grant of £3000. In return, Lyons were given permission to build a copy once EDSAC was complete. The Lyons machine based on the EDSAC design, LEO I, was the first commercial computer.

EDSAC used the following components:

  • 5-hole punched paper tape for input
  • A teleprinter for output
  • Mercury delay lines for memory
  • Vacuum tubes for logic

Related information:


  • Maurice Wilkes and Bill Renwick in front of the completed EDSAC
    Credit: Copyright Department of Computer Science and Technology, University of Cambridge. Reproduced by permission.

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EDSAC runs its first program

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