National Physical Laboratory



The development of computers in the second half of the twentieth century was revolutionary. The need for a machine that solved problems emerged during the Second World War to carry out code deciphering, the computation of trajectories of missiles and flight simulation.

Britain's first programmable electronic computer, the Pilot ACE machine, was built in 1950 at the National Physical Laboratory (NPL), making it the fourth group in the world to achieve a working general-purpose stored-program computer.

Alan Turing was NPL's pioneer in computing research; rather than needing an operator to repeating remove material from the machines and replacing it at the right moment, the Pilot ACE machine tackled whole problems.

What set Pilot ACE apart from its contemporaries was Turing's system of optimum coding - when the chosen program for the Pilot ACE had been created, the programmers also had to decide how to store each instruction in the memory so that the program could be carried out in the fastest time possible. Other computers at the time simply had the instructions stored at random in the memory.

It gave five years of valiant service and its popularity led to the development of a commercial version, DEUCE, in 1955. The Pilot ACE then retired to the Science Museum.

Find out more about Alan Turing and his time at NPL

NPL played a leading role in the use of computers in communications. In 1966, Donald Davies proposed the idea of 'Packet-Switching', a fast message-switching service, which worked by automatically splitting long messages into chunks and sending them separately. This technique formed the basis of current computer communication systems today.

By the late 1960s, many organisations such as banks, airlines and public utilities were using large central multi-access computers and setting up their own data networks. In 1970, the NPL Network was established, constituting the first local-area network in the world.

See a timeline of key NPL Computing dates

Related Links

NPL IT Open Day 1982, Kenneth Baker Speech 
The Pilot Ace
David Yates talks about 'Scrapbook'
The Story of Packet Switching


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