2009's major milestone for computing pioneers

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    Next year marks the 60th anniversaries of two landmark UK contributions to business computing history. The Manchester Mark 1, pictured above, and Edsac computers both became fully operational in 1949.

    Scientists working at the British universities of Manchester and Cambridge developed the machines, which are remarkable for notching up several computing firsts.

    The Manchester Mark 1, for example, was to become the first machine to use a type of index register, improving program and memory efficiency. It was also the system on which Autocode, one of the first high-level languages, was later developed.

    Photograph © The University of Manchester 1998, 1999

    Caption by: Toby Wolpe

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    Cambridge University's Edsac, or Electronic Delay Storage Automatic Calculator, pictured above, is considered the first practical example of a machine holding program instructions in memory.

    However, the significance of Edsac and the Manchester Mark 1 does not stop there. Both machines went on to form the basis of two milestone commercial systems: Edsac spawned Leo 1, while the Manchester computer was the immediate forerunner of the Ferranti Mark 1.

    Leo 1 was the world's first business computer. From September 1951, it ran an application called Bakeries Valuations, organising logistics for catering company Lyons's famous tea shops and London Corner Houses.

    The Ferranti Mark 1 became the world's first commercially available computer in February 1951, beating America's Univac 1 to market by as little as one month, according to some estimates.

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

    Caption by: Toby Wolpe

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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

    Caption by: Toby Wolpe

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    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

    Caption by: Toby Wolpe

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    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

    Caption by: Toby Wolpe

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    Manchester's computer scientists based their Mark 1 system on Williams tube memory — also known as the Williams-Kilburn tube — which uses residual charges on cathode ray tubes to store information. An electron gun scanned across the phosphor created a field of bright dots and dark spaces corresponding to ones and zeros, and if the image was rescanned before it faded then the current through the electron gun changed according to the pattern laid down before.

    The tubes were invented by Tom Kilburn and Sir Frederic Williams, pictured above at the Manchester Mark 1 console.

    These tubes could hold up to 2,048 bits of data and were faster than mercury delay-line storage, but wore out more quickly.

    Among the scientists working on the Manchester Mark 1 project was mathematician Mary Lee Woods who later married fellow team member Conway Berners-Lee. Their son is web pioneer Sir Tim Berners-Lee.

    Photograph © The University of Manchester 1998, 1999

    Caption by: Toby Wolpe

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Manchester's computer scientists based their Mark 1 system on Williams tube memory — also known as the Williams-Kilburn tube — which uses residual charges on cathode ray tubes to store information. An electron gun scanned across the phosphor created a field of bright dots and dark spaces corresponding to ones and zeros, and if the image was rescanned before it faded then the current through the electron gun changed according to the pattern laid down before.

The tubes were invented by Tom Kilburn and Sir Frederic Williams, pictured above at the Manchester Mark 1 console.

These tubes could hold up to 2,048 bits of data and were faster than mercury delay-line storage, but wore out more quickly.

Among the scientists working on the Manchester Mark 1 project was mathematician Mary Lee Woods who later married fellow team member Conway Berners-Lee. Their son is web pioneer Sir Tim Berners-Lee.

Photograph © The University of Manchester 1998, 1999

Caption by: Toby Wolpe

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