The Raspberry Pi is a credit card-sized motherboard, sold without a case, which can be connected to a TV, monitor, mouse or keyboard.
The stripped-down computer is part of an effort to boost British children's programming skills and revive the 1980s era, when hundreds of thousands of schoolchildren learned to code on ZX Spectrums and Commodore 64 computers at home. Much of the UK's successful computer games industry was created by boys who started developing games on these types of devices in their bedrooms.
The launch comes as Michael Gove, education secretary, attempts to overhaul the IT curriculum in UK schools to include more hands-on programming. IT leaders, such as Google's Eric Schmidt, have criticised the UK's IT education as inadequate. "Initiatives like the Raspberry Pi scheme will give children the opportunity to learn the fundamentals of programming," Mr Gove said in a speech last summer outlining the changes.
The UK scientific community has welcomed the project.
"This is a fantastic concept â€“ reuniting children's creativity with computing technology. It brings the aspirations of the 1980s BBC Micro and Computer Literacy Project to a new generation," said Tilly Blyth, curator of computing and information at the Science Museum.
"It also comes at an opportune time â€“ with changes in the school ICT curriculum and the desire to get people programming again, it's an excellent opportunity to get young people into engineering, and programming â€“ who knows it might inspire the next Alan Turing or Steve Jobs out there."
The device has been developed by a charitable foundation, backed by the University of Cambridge Computer Laboratory and Broadcom, the semiconductor company.
The units are being manufactured in China and distributed by UK companies Premier Farnell and RS Components. Demand was so high that the website of the Raspberry Pi foundation crashed on Wednesday. Premier Farnell reported half a million hits in 15 minutes, and RS Components said it was the greatest level of demand it had ever received for a product at one time.
The distributors have limited orders to one per customer in the beginning but say larger orders will be taken in a month's time. A cheaper £16 version of the computer will go on sale later in the year.
Britain's pioneering role
Starting with Charles Babbage, the 19th-century mathematician and engineer who originated the concept of a programmable computer, and Alan Turing, who helped create the Enigma machine that deciphered Nazi codes during the second world war, the UK has often played a pioneering role in the history of computing.
The golden era, however, is often seen as the early 1980s, when the BBC Computer Literacy Project released a series of modestly priced microcomputers for schools. At the same time, entrepreneur Clive Sinclair produced the first mass-market home computer for less than £100, the Sinclair ZX80.
An army of youngsters learning programming on cheap home computers from Sinclair, Commodore and Amstrad in the 1980s went on to found highly successful computer games companies in the 1990s. At that time, the UK was the third largest computer games producer in the world, the creator of titles such as Lara Croft: Tomb Raider and Grand Theft Auto.
Acorn Computers, which had developed the BBC Micro, was broken up but one of its subsidiaries became Arm Holdings, the semiconductor designer whose technology powers nearly all of the world's mobile phones today.
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