First electronic computer (1943) :the building of Colossus
By designing a huge machine now generally regarded as the world's first programmable electronic computer,the then Post Office Research Branch played a crucial but secret role in helping to win the Second World War.The purpose of Colossus was to decipher messages that came in on a German cipher machine,called the Lorenz SZ.
The original Colossus used a vast array of telephone exchange parts together with 1,500 electronic valves and was the size of a small room,weighing around a ton.This 'string and sealing wax affair' could process 5,000 characters a second to run through the many millions of possible settings for the code wheels on the Lorenz system in hours - rather than weeks.
Both machines were designed and constructed by a Post Office Research team headed by Tommy Flowers at Dollis Hill and transported to the secret code-breaking centre at Bletchley Park,near Milton Keynes,where it was demonstrated on December 8,1943.We have to fast forward nearly thirty years to 1972 for the arrival of the first desktop all-in-one computer,which are more familar to us today.That honour falls to the HP9830.But unfortunately few people got to hear about it because Hewlett Packard marketed it primarily to scientists and engineers - by nature very quiet people!