Mary Coombs, teashops and Leo the computer

by Jo Brodie, Queen Mary University of London

Image by Pexels from Pixabay

Tea shops played a surprisingly big role in the history of computing. It was all down to J. Lyons & Co., a forward thinking company that bought one of the first computers to use for things like payroll. Except they had a problem. Computers need programs, but no such programs existed, and neither did the job of programmer. How then to find people to program their new-fangled computer? One person they quickly found, Mary Coombs, suited the job to a T, becoming the first female commercial programmer.

J Lyons and Company, a catering company with a chain of over 200 tea shops in London, wanted to increase its sales and efficiency. With amazing foresight, they realised computers, then being used only for scientific research in a few universities, would help. They bought the technology from Cambridge University, built their own and called it LEO (the Lyons Electronic Office). They hoped it would do calculations much more quickly than the 1950s clerks could, using calculating machines. But it could only happen if Lyons could find people to program it. At the time there were only a handful of people in the world who were ‘good at computers’ (programmer didn’t exist as a job yet) so instead they had to find people who could be good with computers and train them for the job. Lyons created a Computer Appreciation Course which involved a series of lectures and some homework, all designed to find staff within the company who could think logically and would learn how to write programs for LEO.

One of those was Mary Coombs. Born in 1929, she studied at Queen Mary University of London in the late 1940s. You might think, given that this is about a computer, that she studied computer science, but she actually studied French and History. She couldn’t study computer science: what we’d call a computer science course didn’t exist. There wasn’t one anywhere until 1953, when the University of Cambridge opened a Diploma in Computer Science.

By then, Mary was already working at Lyons. She’d had a holiday job there in 1951, as a clerk (in the Ice Cream Sales department) as she finished her degree. A year later she returned to the company where her career changed direction. In addition to her language skills, she was good at maths so transferred to Lyon’s Statistical Office. That’s where she heard about LEO and the need for programmers to learn about it and help test it as it was being built and refined. Intrigued, she signed up for the company’s first computer appreciation course, did well, and was one of only two people on the course then offered a job on the project. As a result she became the first woman to work on the LEO team as a programmer and the first female commercial programmer in the world.

LEO was an enormous computer, built from several thousand valves, and took up an entire room, though it could only store a few kilobytes of memory. It was also a little temperamental. It needed to be very reliable if it was going to be of any use, so it underwent months of testing and improvement, with Mary’s help, before it was put to work on solving real problems, again with Mary and others on the team writing the programs for everything it did.

One of its first tasks was to make sure everyone got paid! LEO was able to calculate forty people’s payslips in one minute (one every 1.5 seconds) where previously it would have taken one clerk six minutes to do one: a huge improvement in efficiency for Lyons.

LEO was both pioneering and a big success, but the real pioneers were the programmers like Mary. They turned computers, intended to help scientists win Nobel prizes, into ones that helped businesses run efficiently, ensuring people got paid. Obvious now, but remarkable in the 1950s.

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This article was funded by UKRI, through Professor Ursula Martin’s grant EP/K040251/2 and grant EP/W033615/1.

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