A UK computer pioneer remembered

NO ONE PERSON invented computing. Charles Babbage had the idea but not the technology back in the nineteenth century. Alan Turing described a computer in abstract in the 1930s. Colossus, used by codebreakers at Bletchley Park in World War II, was tailored for a specific set of tasks. But by the end of the war computing as we know it was bursting to be born.

Among its many midwives was Sir Maurice Wilkes, who has just died at the age of 97. He built Edsac, the world's first operational general-purpose digital computer, which ran its first program on May 6, 1949, at the Cambridge Mathematical Laboratory.

It was a tremendous achievement but when I interviewed him (pdf) in 2003, charming and still sharp as a tack at the age of 89, he was the first to point out that he had built heavily on the work of others.

Wilkes went up to Cambridge University in the same year as Turing, of whom he was a little dismissive. "He didn't know how to get a project going... His record of achievement is really very slight." Wilkes took his doctorate on radio waves in 1934 but joined the Mathematical Lab - now the Computer Laboratory - in 1937 to work on analog computers. After wartime work on radar he returned to Cambridge as head of the lab.

"There was a wonderful feeling of reconstruction in the world," he told me. "Everyone felt this excitement of establishing peacetime values."

Out of the blue he got an invite in 1946 to a series of lectures at Philadelphia's Moore School, given by Presper Eckert and John Mauchly, who had led the team that built the then recently-completed Eniac gunnery computer, which was decimal rather than binary. Wilkes, who had to get to the US by sea, arrived late but by the time he left Philadelphia he reckoned he had learned all he needed to know to build a computer.

Wilkes's Edsac was one of several projects to emerge from that conference. Edvac, the binary computer developed by Eckert and Mauchly, did not go fully operational until 1951. But, as Wilkes pointed out, they had to build one to commercial standards. Edsac was intended only for university use and its designers cut a lot of corners.

Manchester University's Baby, built by Tom Kilburn and Freddie Williams, was up and running earlier in April 1948, and is said to be the world's first stored-program electronic digital computer. But it was a proof of concept rather than a working machine. Edsac was in use for years and was the basis for the Leo, the first dedicated business computer, built by the Lyons teashop chain.

Wilkes headed the Cambridge Computer Laboratory until 1980, when he spent five years with Digital Equipment Corporation in Massachusetts. After a spell at Cambridge's Olivetti lab he rejoined the Computer Lab in 2002 as emeritus professor.

Remarkably, when I asked him what was the most exciting moment of his working life, he cited not Edsac's first successful run but his witnessing of the first data transmission across the Atlantic. "And error correction," he mused. "When I first understood error correction and realised you could send data along lines anywhere. I could see it would change everything." µ