The story
Founded by Andy Hopper, Christopher Curry and Hermann Hauser on Dec 5, 1978.1
Early history
On 25 July 1961, Clive Sinclair founded Sinclair Radionics to develop and sell electronic devices such as calculators. The failure of the Black Watch wristwatch and the calculator market's move from LEDs to LCDs led to financial problems, and Sinclair approached a government body, the National Enterprise Board (NEB), for help. Over time, the NEB took control of the company.
After losing control of the company, Sinclair encouraged Chris Curry to leave Radionics and get Science of Cambridge (SoC—an early name for Sinclair Research) up and running. In June 1978, SoC launched a microcomputer kit, the MK14. Curry wanted to develop it further, but Sinclair could not be persuaded, so Curry resigned. During the development of the MK14, Hermann Hauser, a friend of Curry's, had been visiting SoC's offices and had grown interested in the product.
CPU Ltd. (1978–1983)
Curry and Hauser decided to pursue their joint interest in microcomputers and, on 5 December 1978, they set up Cambridge Processor Unit Ltd. (CPU) as the vehicle with which to do this. CPU soon obtained a consultancy contract to develop a microprocessor-based controller for a fruit machine for Ace Coin Equipment (ACE) of Wales. The ACE project was started at office space obtained at 4a Market Hill in Cambridge. Initially, the ACE controller was based on a National Semiconductor SC/MP microprocessor, but soon the switch to a MOS Technology 6502 was made.
The microcomputer systems
CPU had financed the development of a SC/MP based microcomputer system using the income from its design-and-build consultancy.
This system was launched in January 1979 as the first product of Acorn Computer Ltd., a trading name used by CPU to keep the risks of the two different lines of business separate. Acorn was chosen because the microcomputer system was to be expandable and growth-oriented. It also had the attraction of appearing before "Apple Computer" in a telephone directory.
Around this time, CPU and Andy Hopper set up Orbis Ltd. to commercialise the Cambridge Ring networking system Hopper had worked on for his PhD, but it was soon decided to bring him into CPU as a director because he could promote CPU's interests at the University of Cambridge Computer Laboratory.
CPU purchased Orbis, and Hopper's Orbis shares were exchanged for shares in CPU Ltd. CPU's role gradually changed as its Acorn brand grew, and soon CPU was simply the holding company and Acorn was responsible for development work.
At some point, Curry had a disagreement with Sinclair and formally left Science of Cambridge, but did not join the other Acorn employees at Market Hill until a little while later.
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The Acorn Microcomputer, later renamed the Acorn System 1, was designed by Sophie Wilson. It was a semi-professional system aimed at engineering and laboratory users, but its price was low enough, at around £80 (equivalent to £440 in 2024), to appeal to the more serious enthusiast as well. It was a very small machine built on two cards, one with an LED display, keypad, and cassette interface (the circuitry to the left of the keypad), and the other with the rest of the computer (including the CPU). Almost all CPU signals were accessible via a Eurocard connector.
The System 2 made it easier to expand the system by putting the CPU card from the System 1 in a 19-inch (480 mm) Eurocard rack that allowed a number of optional additions. The System 2 typically shipped with keyboard controller, external keyboard, a text display interface, and a cassette operating system with built-in BASIC interpreter.
The System 3 moved on by adding floppy disk support, and the System 4 by including a larger case with a second drive. The System 5 was largely similar to the System 4, but included a newer 2 MHz version of the 6502.
The Atom
Development of the Sinclair ZX80 started at Science of Cambridge in May 1979. Learning of this probably prompted Curry to conceive the Atom project to target the consumer market. Curry and another designer, Nick Toop, worked from Curry's home in the Fens on the development of this machine. It was at this time that Acorn Computers Ltd. was incorporated and Curry moved to Acorn full-time.
It was Curry who wanted to target the consumer market. Other factions within Acorn, including the engineers, were happy to be out of that market, considering a home computer to be a rather frivolous product for a company operating in the laboratory equipment market.
To keep costs down and not give the doubters reason to object to the Atom, Curry asked industrial designer Allen Boothroyd to design a case that could also function as an external keyboard for the microcomputer systems.
The internals of the System 3 were placed inside the keyboard, creating a quite typical set-up for an inexpensive home computer of the early 1980s: the relatively successful Acorn Atom.
To facilitate software development, a proprietary local area network had been installed at Market Hill. It was decided to include this, the Econet, in the Atom, and at its launch at a computer show in March 1980, eight networked Atoms were demonstrated with functions that allowed files to be shared, screens to be remotely viewed and keyboards to be remotely slaved.
BBC Micro and the Electron
After the Atom had been released into the market, Acorn contemplated building modern 16-bit processors to replace the Atom. After a great deal of discussion, Hauser suggested a compromise—an improved 6502-based machine with far greater expansion capabilities: the Proton. Acorn's technical staff had not wanted to do the Atom and they now saw the Proton as their opportunity to "do it right".
One of the developments proposed for the Proton was the Tube, a proprietary interface allowing a second processor to be added. This compromise would make for an affordable 6502 machine for the mass market which could be expanded with more sophisticated and expensive processors. The Tube enabled processing to be farmed out to the second processor leaving the 6502 to perform data input/output (I/O). The Tube would later be instrumental in the development of Acorn's ARM processor.
In early 1980, the BBC Further Education department conceived the idea of a computer literacy programme, mostly as a follow-up to an ITV documentary, The Mighty Micro, in which Dr Christopher Evans from the UK National Physical Laboratory predicted the coming microcomputer revolution. It was a very influential documentary—so much so that questions were asked in Parliament. As a result of these questions, the Department of Industry (DoI) became interested in the programme, as did BBC Enterprises, which saw an opportunity to sell a machine to go with the series. BBC Engineering was instructed to draw up an objective specification for a computer to accompany the series.
Eventually, under some pressure from the DoI to choose a British system, the BBC chose the NewBrain from Newbury Laboratories. This selection revealed the extent of the pressure brought to bear on the supposedly independent BBC's computer literacy project—Newbury was owned by the National Enterprise Board, a government agency operating in close collaboration with the DoI. The choice was also somewhat ironic given that the NewBrain started life as a Sinclair Radionics project, and it was Sinclair's preference for developing it over Science of Cambridge's MK14 that led to Curry leaving SoC to found CPU with Hauser. The NEB moved the NewBrain to Newbury after Sinclair left Radionics and went to SoC.
In 1980–1982, the British Department of Education and Science (DES) had begun the Microelectronics Education Programme to introduce microprocessing concepts and educational materials. In 1981, through to 1986, the DoI allocated funding to assist UK local education authorities to supply their schools with a range of computers, the BBC Micro being one of the most popular. Schools were offered 50% of the cost of computers, providing they chose one of three models: BBC Micro, ZX Spectrum or Research Machines 380Z. In parallel, the DES continued to fund more materials for the computers, such as software and applied computing projects, plus teacher training.
Although the NewBrain was under heavy development by Newbury, it soon became clear that they were not going to be able to produce it—certainly not in time for the literacy programme nor to the BBC's specification. The BBC's programmes, initially scheduled for autumn 1981, were moved back to spring 1982. After Curry and Sinclair found out about the BBC's plans, the BBC allowed other manufacturers to submit their proposals. Hauser quickly drafted in Steve Furber (who had been working for Acorn on a voluntary basis since the ACE fruit machine project) and Sophie Wilson to help complete a revised version of the Proton which met the BBC's specifications. BBC visited Acorn and were given a demonstration of the Proton. Shortly afterwards, the literacy programme computer contract was awarded to Acorn, and the Proton was launched in December 1981 as the BBC Micro. In April 1984, Acorn won the Queen's Award for Technology for the BBC Micro. The award paid special tribute to the BBC Micro's advanced design, and it commended Acorn "for the development of a microcomputer system with many innovative features".
In April 1982, Sinclair launched the ZX Spectrum. Curry conceived of the Electron as Acorn's sub-£200 competitor. In many ways a cut-down BBC Micro, it used one Acorn-designed uncommitted logic array (ULA) to reproduce most of the functionality. But problems in producing the ULAs led to short supply, and the Electron, although launched in August 1983, was not on the market in sufficient numbers to capitalise on the 1983 Christmas sales period. Acorn resolved to avoid this problem in 1984 and negotiated new production contracts. Acorn became more known for its BBC Micro model B than for its other products.
In 2008, the Computer Conservation Society organised an event at London's Science Museum to mark the legacy of the BBC Micro. A number of the BBC Micro's principal creators were present, and Sophie Wilson recounted to the BBC how Hermann Hauser tricked her and Steve Furber to agree to create the physical prototype in less than five days. Also in 2008 a number of former staff organised a reunion event to mark the 30th anniversary of the company's formation.
1983–1985: Acorn Computer Group
The BBC Micro sold well—so much so that Acorn's profits rose from £3000 in 1979 to £8.6 million in July 1983. In September 1983, CPU shares were liquidated and Acorn was floated on the Unlisted Securities Market as Acorn Computer Group plc, with Acorn Computers Ltd. as the microcomputer division. With a minimum tender price of 120p, the group came into existence with a market capitalisation of about £135 million. CPU founders Hermann Hauser and Chris Curry's stakes in the new company were worth £64m and £51m, respectively. Ten per cent of the equity was placed on the market, with the money raised from the flotation "mainly" directed towards establishing US and German subsidiaries (the flotation raising around £13.4 million), although some was directed towards research and product development.
By the end of 1984, Acorn Computer Group was organised into several subsidiary companies. Acorn Computers Limited was responsible for the management of the microcomputer business, research and development, and UK sales and marketing, whereas Acorn Computer Corporation and Acorn Computers International Limited dealt with sales to the US and to other international markets respectively. Acorn Computers (Far East) Limited focused on component procurement and manufacturing with some distribution responsibilities in local markets. Acornsoft Limited was responsible for development, production and marketing of software for Acorn's computer range. Vector Marketing Limited was established to handle distribution-related logistics and the increasing customer support burden. As part of Acorn's office automation aspirations, conducting "advanced software research and development", Acorn Research Center Incorporated was established in Palo Alto, California. Acorn Leasing Limited rounded out the portfolio.
New RISC architecture
Even from the time of Acorn's earliest systems, the company was considering how to move on from the 6502 processor, introducing a Motorola 6809 processor card for its System 3 and System 4 models. Several years later in 1985, the Acorn Communicator employed the 16-bit 65816 processor as a step up from the 6502.
The IBM PC was launched on 12 August 1981. Although a version of that machine was aimed at the enthusiast market much like the BBC Micro, its real area of success was business. The successor to the PC, the XT (eXtended Technology) was introduced in early 1983. The success of these machines and the variety of Z80-based CP/M machines in the business sector demonstrated that it was a viable market, especially given that sector's ability to cope with premium prices. The development of a business machine looked like a good idea to Acorn. A development programme was started to create a business computer using Acorn's existing technology: the BBC Micro mainboard, the Tube and second processors to give CP/M, MS-DOS and Unix (Xenix) workstations.
This Acorn Business Computer (ABC) plan required a number of second processors to be made to work with the BBC Micro platform. In developing these, Acorn had to implement the Tube protocols on each processor chosen, in the process finding out, during 1983, that there were no obvious candidates to replace the 6502. Because of many-cycle uninterruptible instructions, for example, the interrupt response times of the Motorola 68000 were too slow to handle the communication protocol that the host 6502-based BBC Micro coped with easily. The National Semiconductor 32016-based model of the ABC range, was developed and later sold in 1985 as the Cambridge Workstation (using the Panos operating system). Advertising for this machine in 1986 included an illustration of an office worker using the workstation. The advert claimed mainframe power at a price of £3,480 (excluding VAT). The main text of the advertisement referred to available mainframe languages, communication capabilities and the alternative option of upgrading a BBC Micro using a coprocessor. The machine had shown Sophie Wilson and Steve Furber the value of memory bandwidth. It also showed that an 8 MHz 32016 was completely trounced in performance terms by a 4 MHz 6502. Furthermore, the Apple Lisa had shown the Acorn engineers that they needed to develop a windowing system; this was not going to be easy with a 2–4 MHz 6502-based system doing the graphics. Acorn would need a new architecture.
Acorn had investigated all of the readily available processors and found them wanting or unavailable to them. After testing all of the available processors and finding them lacking, Acorn decided that it needed a new architecture. Inspired by white papers on the Berkeley RISC project, Acorn seriously considered designing its own processor. A visit to the Western Design Center in the US, where the 6502 was being updated by what was effectively a single-person company, showed Acorn engineers Steve Furber and Sophie Wilson they did not need massive resources and state-of-the-art research and development facilities.
Sophie Wilson set about developing the instruction set, writing a simulation of the processor in BBC BASIC that ran on a BBC Micro with a 6502 second processor. It convinced the Acorn engineers that they were on the right track. Before they could go any further, however, they would need more resources. It was time for Wilson to approach Hauser and explain what was afoot. Once the go-ahead had been given, a small team was put together to implement Wilson's model in hardware.
Acorn initiated its RISC research project in October 1983, and by 1987 had spent £5 million. VLSI Technology, Inc were chosen as silicon partner, since they already supplied Acorn with ROMs and some custom chips. VLSI produced the first ARM silicon on 26 April 1985; it worked first time and came to be known as ARM1. Its first practical application was as a second processor to the BBC Micro, where it was used to develop the simulation software to finish work on the support chips (VIDC, IOC, MEMC) and to speed up the operation of the CAD software used in developing ARM2. The ARM evaluation system was promoted as a means for developers to try the system for themselves. This system was used with a BBC Micro and a PC compatible version was also planned. Advertising was aimed at those with technical expertise, rather than consumers and the education market, with a number of technical specifications listed in the main text of the adverts. Wilson subsequently coded BBC BASIC in ARM assembly language, and the in-depth knowledge obtained from designing the instruction set allowed the code to be very dense, making ARM BBC BASIC an extremely good test for any ARM emulator.
Such was the secrecy surrounding the ARM CPU project that when Olivetti were negotiating to take a controlling share of Acorn in 1985, they were not told about the development team until after the negotiations had been finalised. In 1992, Acorn once more won the Queen's Award for Technology for the ARM. Acorn's development of their RISC OS operating system required around 200 OS development staff at its peak. Acorn C/C++ was released commercially by Acorn, for developers to use to compile their own applications.
Financial problems
Having become a publicly traded company in 1983 during the home computer boom, Acorn's commercial performance in 1984 proved to be consequential. Many home computer manufacturers struggled to maintain customer enthusiasm, some offering unconvincing follow-up products that failed to appeal to buyers. The more successful manufacturers, like Amstrad, emphasised the bundling of computers with essential peripherals such as monitors and cassette recorders along with value for money. The collapse of the market from the manufacturers' perspective, it was argued, was due to the "neglect of the market by the manufacturers". Market adversity had led to Atari being sold, and Apple nearly went bankrupt.
The Electron had been launched in 1983, but problems with the supply of its ULA meant that Acorn was not able to capitalise on the 1983 Christmas selling period. A successful advertising campaign, including TV advertisements, had led to 300,000 orders, but the Malaysian suppliers were only able to supply 30,000 machines. The apparently strong demand for Electrons proved to be ephemeral: rather than wait, parents bought Commodore 64 or ZX Spectrum for their children's presents. Ferranti solved the production problem and in 1984, production reached its anticipated volumes, but the contracts Acorn had negotiated with its suppliers were not flexible enough to allow volumes to be reduced quickly in this unanticipated situation, and supplies of the Electron built up. At the time of the eventual financial rescue of Acorn in early 1985, it still had 100,000 unsold Electrons plus an inventory of components which had all been paid for and needed to be stored at additional expense. 40,000 BBC Micros also remained unsold.
From Wikipedia’s article on Acorn Computers, shared under CC BY-SA 4.0.3