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61859 Derek Hemy at the blackboard (1952)

Description of Photograph

Digital copy of a photograph of Derek Hemy, one of the first LEO I programmers, after the first successful test of LEO I.

Caption:  'Derek Hemy at the scoreboard of the continuous reliability test. [ms] Jan 1952'.

This image appears in the interactive plan for our Virtual LEO I installation, p70.

Related image: Ernest Lenaerts and Derek Hemy at the blackboard (CMLEO/PB/PH/1/54266).


Research comments: In this photograph Derek Hemy, who was one of LEO's earliest programmers, is writing on a blackboard in the calculator room at Cadby Hall during a 1952 test of the reliability of the computer. Reliability was key if LEO was to be entrusted with the critical office functions (like payroll and teashop supplies) that underpinned the success of Lyons as a business. According to the blackboard, the calculator has been calculating tax tables at this point for 36 hours, suffering 5 breakdowns that lasted 83 minutes and wasted 2.5 hours of work during that time. In total, according to the LEO Chronicle, over the period 10th-12th January 1952 LEO ran for over 59 hours in total, of which over 51 hours was useful work. This gave an operational efficiency of 87%.

At the bottom of the blackboard cricket information can also be seen; the LEO team was full of cricket lovers and they recorded the state of play in the current big match at the same time as recording the state of play with LEO. (LM)


Digital copy made by John Daines, LEO Computers Society, of a photograph in the LEO Computers Collection (formerly part of the National Archive of Historic Computing) at the University of Manchester Library: NAHC/LEO/B1-28

Date: 12th January 1952

Physical Description: 1 digital image (jpeg); black & white; image includes original typed caption

Archives Hub References: CMLEO/LS/PH/1/61859

Other References: DCMLEO20210214023
Related Topics:

Comment on This Photograph

This exhibit has a reference ID of CH61859. Please quote this reference ID in any communication with the Centre for Computing History.

Photograph of 61859  Derek Hemy at the blackboard  (1952)

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