The world's first supercomputer, built at the University of Manchester by a group led by Tom Kilburn in collaboration with Ferranti, was formally switched on on December 7, 1962.
Scientists and engineers who worked on the UK’s pioneering Atlas computer together with many of its end users gathered in Manchester this week to celebrate its 50th anniversary.
Sir John Cockcroft switches on Atlas at Manchester University on December 7th, 1962. Sebastian de Ferranti (left) and
Tom Kilburn (right) look on.
The first production Atlas was inaugurated at Manchester University on 7th December 1962 by Sir John Cockcroft, the Nobel prize-winning physicist who was Director of the UK’s Atomic Energy Authority. At the time the Atlas was the world’s most powerful computing device and according to computer historians when it was switched on the UK's scientific computing capacity instantly doubled.
In the period after World War II, Manchester was one of foremost centers of computing expertise. Tom Kilburn's group had completed the Small-Scale Experimental Machine (SSEM) better known as "Baby“ in 1948 and followed on with the wold's first stored program computer, Manchester Mark I in 1949. Its next machine, the Mark II or MEG, standing for MEGacycle, was converted into a commercial machine by Ferranti with the support of the NRDC (National Research and Development Council) which in 1951 agreed to order four machines.
Despite this early lead, by the mid 1950's there was a dearth of computing power available. Professor Simon Lavington, who started using Atlas as a research student in 1962, and who has produced an illustrated pdf, The Atlas Story, tells us that by 1955 there were fewer than 16 production digital computers in use in the UK and they were all single-user systems with practically no systems software; each had primary memories of 4K bytes or less and could obey about 1,000 instructions per second.
Tom Kilburn's impetus to build a more ambitious machine stemmed, according to Lavington, to two factors:
the urgent need of the UK’s nuclear physicists for more powerful computers, and the knowledge that the Americans were planning new machines such as the IBM STRETCH that could probably satisfy the physicists’ needs. In short, the early lead in computers that the UK had achieved in the period 1948 – 51 had slipped away.
Kilburn's project, which started under the macron MUSE aimed was to use new technologies and new concepts to build a multi-user computer having a primary memory of at least 500Kbytes and a speed of about one million instructions per second.
It was when Ferranti officially came on board in 1959 that name Atlas was adopted. And it was once NRDC, which had already been attempting to organise a project to build a British Supercomputer (a term first mentioned an NRDC meeting of January 1957), agreed to support the venture with a loan of £300,000 towards the cost of development that the first Pilot Version of Atlas was built.
The pilot Atlas in the Department of Electrical Engineering, University of Manchester, in 1960
Three production versions of the Atlas I were produced with the University of Manchester being the first. The second was delivered to a joint BP/London University consortium in 1963 and the third and largest went to the Science Research Council’s laboratory at Chilton, near Harwell in 1964.
Ferranti later sold two production models of the Atlas 2, a less complex and thus cheaper version of the Altas.
Despite being a commercial failure Atlas was highly successful in other respects. It was used to teach programming at Machester until 1971 and the Chilton Atlas greatly increased the throughput of the Science Research Council. In 1966 its Director, Jack Howlett wrote in his annual Report:
“In a typical week we run 2,500 jobs, input 800,000 cards and 30 miles of paper tape, print 1.8 million lines of output, punch 50,000 cards, handle 1,200 reels of magnetic tape. We have 250 projects on our books from university users and are usually doing work on 100 of these"
Atlas was also the machine that the idea for virtual memory, known at the time as a "single-level store" was first worked out and this is an innovation that is still as important today.