Englishman Charles Babbage conceived the basic idea of a computer about 150 years ago, as a machine that would eliminate error and relieve humans of the tedium of calculation. But it was not until the Second World War that the race to build the first computer began. In 1946, the Americans unveiled the ENIAC - it filled a large room, cost the equivalent of $3 million to build and had less power than a modern pocket calculator.

Interviews:

Paul Ceruzzi (computer historian), Doron Swade (London Science Museum), Konrad Zuse (inventor of the first functional computer and high-level programming language, d.1995), Kay Mauchly Antonelli (human computer in WWII and ENIAC programmer, d.2006), Herman Goldstine (ENIAC developer, d.2004), J. Presper Eckert (co-inventor of ENIAC, d.1995), Maurice Wilkes (inventor of EDSAC), Donald Michie (Codebreaker at Bletchley Park)