2009's major milestone for computing pioneers

2009's major milestone for computing pioneers

Summary: Two historic British computers, the Manchester Mark 1 and Edsac, went live 60 years ago next year. Both systems were the immediate forerunners of the first commercial systems

TOPICS: Tech Industry

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  • From the control panel, pictured above, Leo 1's operators eventually ran applications on the 500kHz system that extended from weekly payroll calculations to accounts and management reports. The Edsac-based Leo — or Lyons Electronic Office — started out with punched card and paper tape readers, but later versions switched to magnetic tape.

    Despite initial teething problems, the Leo 1 system became efficient enough for Lyons to offer computing services to other companies, including Ford UK, in what can be seen as a pioneering outsourcing service. Lyons also ended up building Leo machines for external organisations.

    Photograph © 2008 Leo Computers Society

  • Based on the Manchester Mark 1, the Ferranti Mark 1, whose console is pictured above, is hailed today as the first commercially available business computer, but its 1952 sales brochure says much about the importance of commercial applications in that era.

    In the Ferranti 1 brochure's section on applications, after a lengthy discussion of determinants and matrices, ordinary and partial differentials, problems of logical structure, tables of Laguerre polynomials and Laguerre functions, it casually mentions that the machine can be also be used for "commercial and industrial subjects".

    According to Manchester University, early programming on the Ferranti Mark 1 was "horrific by modern standards". It required programmers to work in base 32 — a five-bit group — which meant remembering the 32-letter-shift keyboard characters of a teleprinter and their five-hole equivalents. However, some who have worked that close to the machinery say it gives a unique insight into the way the computer works, and encourages efficiencies unthinkable today.

    Photograph © The University of Manchester 1998, 1999

  • Both groups of scientists behind the Manchester Mark 1 and Edsac computers employed memory technology that had its origins in World War II radar, but their approaches contrasted significantly.

    Edsac's Cambridge designers opted for mercury delay line storage, pictured above with one the system's architects, computing pioneer Sir Maurice Wilkes.

    Delay-line memory works by sending audio pulses corresponding to an information pattern through a medium that creates a delay, in this case a tube of mercury. Then the path is looped back on itself through amplifying and timing circuits, forming a closed loop that refreshes the information. Transducers at the end of the line convert between acoustic energy and electrical signals; for these to work effectively, however, the mercury had to be heated to 40° celsius, making the storage compartment a particularly unpleasant place to work.

    Photograph © 2008 University of Cambridge Computer Laboratory. Reproduced by permission

Topic: Tech Industry

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