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LEO I filled a large room and used 5,936 valves, with another 300-400 in auxiliary equipment, according to the LSE. LEO used 64 mercury tubes — each over five feet in length — for storage, each tube weighing half a ton. The components were assembled in racks to minimise the impact of equipment failure — engineers had to replace up to 50 valves per week during times of heavy failure rates.
This picture shows the LEO I built at Cadby Hall in Hammersmith.
Photo: LEO Computers Society