Acorn Computers

Acorn, Ltd. was a computer company founded in 1978 by Chris Curry and Herman Hauser in Cambridge, Cambridgeshire.

Between 1978 and 1980 they launched a number of 6502 based computers named System 1 (or System One) through System 5. The System 1 was a very small eurocard based machine with LED displays and hexpads for input, useful for experimentation only. The other machines in the series used similar hardware but included a number of options to make them much more practical, including support for text displays and full keyboards. These were all meant to be mounted in full eurocard racks to make up a complet computer with more memory, floppy disks, and display controllers. The System 5 was similar but included a newer 2MHz version of the 6502.

In 1980 they launched their much more successful Acorn Atom microcomputer, which was an all-in-one machine based around the internals of the System 2.

The success of Atom prompted the British Broadcasting Corporation to include Acorn to the list of computer manufacturers with whom they discussed a contract for a microcomputer suitable to back their TV series The Computer Programme.

Acorn had already started working on an upgrade to the Atom, known as the Proton. The Proton was largely similar to the Atom, but included a 2MHz version of the 6502 (like the System 5), upgraded display output, newer RS423 serial ports, and a "user port" which included much of the backplane's pins in a slot for expansion.

The BBC awarded Acorn the contract after seeing the prototype Proton, and the machine was renamed as the BBC Microcomputer in November 1981. During the next five years, a number of improved versions of the same design was launched, including the Acorn Electron, BBC Model B+ and BBC Master in several variants.

In 1983 Acorn asked Intel for a sample 80286 processor, and Intel refused. As a result of this refusal a team was set up within Acorn, led by Roger Wilson and Steve Furbur, to try and develop a RISC (Reduced Instruction Set Chip) processor. Such was the secrecy surrounding this project that when Olivetti took a controlling share of Acorn in 1985 they were not told about the development team until after the negotiations had been finalised. This effort led to the ARM (Acorn RISC Machine) chip.

The first ARM-based product was the ARM Development System, a second processor for the BBC Master which allowed one to write programs for the new system. It cost around £4,000 to buy, and included the ARM processor and three support chips, 4 Mb of RAM and a set of development tools with an enhanced version of BBC BASIC.

The second ARM-based product was the Acorn Archimedes, released in mid-1987. The Archimedes was popular in England and was considerably more powerful than most offerings of the day, but the market was already stratifying into the PC dominated world and Acorn eventually left the business.