Acorn Computers: Difference between revisions
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In April 1982 Sinclair launched the [[Sinclair Spectrum|Spectrum]]. Curry conceived of the '''[[Acorn Electron|Electron]]''' as Acorn's sub-200 pound competitor. In many ways a cut-down BBC Micro, it used one Acorn-designed [[uncommitted logic array|ULA]]. But supply of these ULAs meant that 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. |
In April 1982 Sinclair launched the [[Sinclair Spectrum|Spectrum]]. Curry conceived of the '''[[Acorn Electron|Electron]]''' as Acorn's sub-200 pound competitor. In many ways a cut-down BBC Micro, it used one Acorn-designed [[uncommitted logic array|ULA]]. But supply of these ULAs meant that 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. |
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===A new RISC architecture=== <!-- the "ARM architecture" article links to this section heading: if you change this heading, please update the article --> |
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Even from the time of the Atom Acorn were considering how to move on from the 6502 - for example, the 16-bit [[Acorn Communicator]] developed in 1982 using the [[Western Design Center 65816|65816]]. |
Even from the time of the Atom Acorn were considering how to move on from the 6502 - for example, the 16-bit [[Acorn Communicator]] developed in 1982 using the [[Western Design Center 65816|65816]]. |
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Revision as of 15:31, 10 April 2005
| File:AcornComputersLtdLogo.jpg | |
| Company type | Formerly public as Acorn Group plc (LSE:GB0000061167), now delisted |
|---|---|
| Founded | Cambridge, England (December, 1978) |
| Headquarters | Cambridge, England |
Key people | Chris Curry Hermann Hauser Andy Hopper Sophie Wilson |
| Products | System 1 System 2 System 3 System 4 System 5 Atom BBC Micro (aka Proton) BBC Master Electron Communicator Acorn Business Computer Archimedes Risc PC Acorn Online Media Set Top Box Acorn Network Computer Phoebe |
Number of employees | Unknown |
| Website | Formerly www.acorn.com |
Acorn Computers Ltd. was a British computer company based in Cambridge, England. Acorn operated in various forms between 1978 and 2000, producing a number of computers that were especially popular in the UK. These included the Acorn Electron, the BBC Micro and the Acorn Archimedes.
Prehistory: Chris Curry and Sinclair Radionics
On 25 July 1961, Clive Sinclair founded a company called Sinclair Radionics to develop and sell electronic devices such as calculators. In 1976, the company sustained losses due to the failure of its Black Watch digital wristwatch and a change in the fashion of the calculator market away from LEDs and towards LCDs. In an attempt to raise extra capital, Sinclair approached the National Enterprise Board (NEB), which bought a 43 per cent stake in the company in August 1976. After losing control to the NEB, Sinclair agreed with Radionics employee Chris Curry that Curry would leave Radionics and establish another company, Science of Cambridge (SoC). In June 1978, SoC launched a microcomputer kit (the MK14) based around the National Semiconductor SC/MP chip. Curry wanted to further develop the MK14 but Sinclair was working on the NewBrain. 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. Science of Cambridge eventually became Sinclair Research Ltd.
CPU Ltd
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. Office space was obtained at 4a Market Hill in Cambridge and the ACE project got underway there. The ACE controller was initially SC/MP based but was soon switched to a 6502. At around this time, Hauser and Andy Hopper set up Orbis Ltd to commercialise the Cambridge Ring networking system Hopper had worked on for his PhD.
CPU had developed a 6502-based system that was launched in January 1979 as the first product of Acorn Computer Ltd, a trading name of CPU. Acorn represented an independent fiscal unit in order to keep separate the risks of the two different lines of business. The name Acorn was chosen because the system was going to be expandable and growth-oriented. It also had the attraction of appearing before "Apple" in a telephone directory. Orbis was purchased by CPU and Hopper's shares were exchanged for shares in CPU Ltd. The role of CPU changed as Acorn grew and soon it was simply the holding company. At some point, Curry had a disagreement with Sinclair and formally left Science of Cambridge, but he did not join the other Acorn employees at Market Hill until a little while later.
Acorn System series
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, to appeal to the more serious enthusiast as well. It was a very small machine built on two cards, one (shown right) 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" Eurocard rack which 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 advanced 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 2MHz version of the 6502.
The Atom
In May 1979, the ZX80 project was being developed at Science of Cambridge and it was probably on learning of this that Curry decided to get the Atom project going at Acorn to target the consumer (home) computer 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's desire to target the consumer market. Other factions within Acorn (including the engineers) were happy to be out of the consumer market. They considered the Atom a rather frivolous product for the laboratory equipment market that CPU was targetting. For this reason and to save costs, Acorn 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 setup for an inexpensive home computer of the early 80s era &ndash. This created 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.
The BBC Micro
With the Atom on the market, Acorn began to think about what was needed to replace it. There were new 16-bit processors coming onto the market - should they move in that direction? After a great deal of discussion, Hauser suggested a compromise - an improved 6502-based machine with far greater expansion capabilities. It was to be called the Proton. Acorn's technical staff had not wanted to do the Atom – they saw the Proton as their opportunity to do it "right".1
One of the developments proposed for the Proton was the Tube®: a proprietary interface that would allow the expansion of the Proton with a second processor. In general, the idea was that processing would be farmed out to the second processor leaving the host to perform I/O. In later years the Tube would play an important role in the development of the Acorn RISC Machine processor.
In early 1980, the BBC Further Education department conceived the idea of a computer literacy programme, mostly as a follow-up to a BBC documentary, The Mighty Micro, in which Dr. Christopher Evans from the UK National Physical Laboratory predicted the coming (micro)computer 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, who 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, which was being developed by Newbury Laboratories. This was a rather ironic choice since Acorn had come into existence via Science of Cambridge, which itself came into existence because of the involvement of the National Enterprise Board in Sinclair Radionics. The NewBrain project also started life at Radionics, and had been moved by the NEB to Newbury Labs, which the NEB also owned. 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 spec. 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.
The BBC visited Acorn and were given a demonstration of the Proton. Shortly afterwards, the literacy programme computer contract was was awarded to Acorn and the Proton was launched early in 1982 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".
The Electron
In April 1982 Sinclair launched the Spectrum. Curry conceived of the Electron as Acorn's sub-200 pound competitor. In many ways a cut-down BBC Micro, it used one Acorn-designed ULA. But supply of these ULAs meant that 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.
A new RISC architecture
Even from the time of the Atom Acorn were considering how to move on from the 6502 - for example, the 16-bit Acorn Communicator developed in 1982 using the 65816.
The IBM PC was launched on August 12 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 (and that sector's ability to cope with premium prices) demonstrated that it was a viable market - 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; for example, because of many-cycle uninterruptible instructions, the interrupt response times of the 68000 were too slow to handle the communication protocol that the host 6502-based BBC Micro coped with easily. Development of the National Semiconductor 32016-based model of the ABC range (later sold as the Cambridge Workstation) had shown Sophie Wilson and Steve Furber the value of memory bandwidth. It also showed that an 8MHz 32016 was completely trounced in performance terms by a 4MHz 6502. Furthermore, the Apple Lisa had shown the Acorn engineers that they needed to develop a windowing system - and this was not going to be easy with a 2-4MHz 6502-based system doing the graphics! Acorn would need a new architecture.
Acorn had tested all of the available processors and found them wanting. And when you have excluded the impossible, whatever remains, however improbable, must be the truth! Acorn needed to design its own processor.
Acorn’s engineers came across papers on the Berkeley RISC project. They could now handle the truth - if a class of graduate students could create a competitive 32-bit processor, Acorn would have no problem! A trip to the Western Design Center in Phoenix showed Furber and Wilson that they didn't need massive resources and state-of-the-art R&D 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... but before they could go any further 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. The official Acorn RISC Machine project started in October 1983.
Acorn Computer Group plc
The BBC Micro sold spectacularly well - so much so that Acorn's profits rose from a mere £3000 in 1979 to £8.6m 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 Herman Hauser and Chris Curry leapt instantly into the paper millionaire bracket: Hauser's 53.25 million shares made him worth £64m; Curry's 43 million shares translated into £51m.
Financial problems
1984 was Acorn's watershed year – it had gone public just as the home computer market collapsed. It was the year when Atari was sold, Apple nearly went bust, and Acorn had solved the one problem it had had throughout its history: production volumes.
Supplying the Electron
The Electron had been launched in 1983 but problems with the supply of ULAs 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 illusory: rather than wait, parents bought Commodore 64s or Sinclair Spectrums 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 – supplies of the Electron built up. Acorn was in real trouble: by the end of the year it had 250,000 unsold Electrons on its hands, which had all been paid for and needed to be stored – at additional expense.
Research and development expenditure
Acorn was also spending a large portion of its reserves on development: the BBC Master was being developed, the ARM project was underway and another project was underway, aimed at satisfying Hauser's long-time ambition of entering the business computer market.
Federal approval for the BBC Micro
Acorn had also attempted to expand into the United States, but just getting Federal approval for the BBC Micro was a drawn-out and expensive process. All of the expansion devices that were intended to be sold with the BBC Micro had to be tested and radiation emissions had to be reduced. Around $20m was sunk into the US operation but the NTSC modified BBC Micros sold barely at all, although they did get an appearance at Supergirl's school!
Acorn Business Computer
The ABC range was announced in 1984. The concept was to use the BBC Micro with a range of second processors operating over the Tube - Z80 for CP/M, 80286 running various versions of DOS, a 32016 running PANOS. Only the 32016-based machine was ever marketed; it sold in small numbers as the Cambridge Workstation while the ABC range quietly died. 1984 was also the year in which the Apple Macintosh was launched. Using what was essentially a BBC micro as the graphics controller was now obviously a blind alley. The only realistic option was to leave behind the existing technologies, leapfrog 16-bit and go straight to 32-bit.
Acorn RISC Machine
The ARM project got underway in 1983 with VLSI Technology, Inc as the silicon partner. VLSI produced the first 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. This system was then used to develop the simulation software to finish work on the support chips (VIDC, IOC, MEMC). 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 (a typical Wilson trait), making ARM BBC Basic an extremely good test for any ARM emulator.
The first commercial use of the ARM architecture was in the ARM Development System, a Tube-linked second processor for the BBC Master which allowed one to write programs for the new system. It sold for around £4,000, and included the ARM processor and three support chips, 4MB of RAM and a set of development tools with an enhanced version of BBC BASIC.
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.
Life as an Olivetti subsidiary
On 20 February 1985, after a short period of negotiations, Curry and Hauser signed an agreement with Olivetti giving the Italian computer company a 49.3% stake in Acorn for £12 million. The money went some way to covering Acorn's £11 million losses in the previous six months.
In September 1985 Olivetti took a controlling share of Acorn with 79% of shares.
BBC Master
The BBC Master was launched in February 1986 and met with great success. From 1986 to 1989, about 200,000 systems were sold, mainly to UK schools and universities. A number of enhanced versions were launched - for example, the Master 512, which had 512 KB of RAM and an internal 80186 processor for MS-DOS compatibility, and the Master Turbo, which had a 65C02 second processor.
Archimedes and Risc PC
The second ARM-based product was the Acorn Archimedes desktop-computer, released in mid-1987. The Archimedes was popular in the United Kingdom, Australasia and Ireland, and was considerably more powerful and advanced than most offerings of the day, but the market was already stratifying into the PC dominated world.
Acorn continued to produce updated models of the Archimedes including a laptop (the A4) and the Risc PC where the top specification included a 200MHz+ StrongARM processor. These were sold mainly into education, specialist and enthusiast markets
ARM Ltd
Acorn's silicon partner, VLSI, had been tasked with finding new applications for the ARM CPU and support chips. Hauser's Active Book company had been developing a handheld device and for this the ARM CPU developers had created a static version of their processor, the ARM2aS.
Apple was developing an entirely new computing platform, the Newton. Various requirements had been set for the processor in terms of power consumption, cost and performance and there was also a need for fully static operation in which the clock could be stopped at any time. Only the Acorn RISC Machine came close to meeting all these demands, but there were still deficiencies - the ARM did not, for example, have an integral memory management unit (this function being provided by the MEMC support chip) and Acorn did not have the resources to develop one.
Apple and Acorn began to collaborate on developing the ARM, and it was decided that this would be best achieved by a separate company. The bulk of the Advanced Research and Development section of Acorn that had developed the ARM CPU formed the basis of ARM Ltd when that company was spun off in November 1990. Acorn Group and Apple Computer Inc each had a 43% shareholding in ARM, while VLSI were an investor and first ARM licensee.
Restructuring
Between 1996 and 1998 Olivetti Telemedia disposed of its interest in Acorn Group through a series of structured transactions, raising £54m.
Acorn Online Media: set-top boxes
The Acorn Online Media division was set up in 1994 to exploit the projected Video-On-Demand (VOD) boom. Their product, the Acorn Online Media Set Top Box, was to be an affordable consumer appliance for what it was thought the VOD market would need and formed the basis for the forthcoming Network Computer developments.
Acorn Network Computing: Oracle and the network computer
In February 1996 Acorn set up the Network Computing division to develop network computing products. They were a development of the previous VOD set-top boxes.
In August 1996 it launched the Acorn Network Computer, a diskless device which implemented Oracle's Network Computer Reference Profile. The operating system was strongly based on Risc OS. These machines were Larry Ellison's view of the future of computing through the internet.
Phoebe: the last acorn falls
Acorn finally abandoned producing desktop-computers in late 1998 in favour of set-top boxes when it closed its Workstation Division. The last machine (codenamed "Phoebe" or Risc PC 2) was nearly fully developed at the time of the project's abandonment, and therefore was never produced in volume nor sold to the public (notably, numbers of its distinctive yellow case were produced and sold off cheaply).
In July 1999 Acorn Group plc incorporated Element 14 to concentrate on the digital signal processing (DSP) market. Its engineering centres were in Cambridge and Bristol, UK, and Mechelen, Belgium. The company had £8.25 ($13) million in first round funding led by Bessemer Venture Partners, Atlas Ventures and Hauser's Amadeus Capital Partners.
The end
ARM had gone from strength to strength. In 1998, the Company re-registered as a public company under the name ARM Holdings plc when it completed its initial public offering of shares and listed its shares for trading on the London Stock Exchange and for quotation on the Nasdaq National Market. Morgan Stanley Dean Witter acted as global co-ordinator and bookrunner for the Offering as well as sponsor and broker for the listing on the London exchange.
By 1999 ARM's share value had increased to a point where the capital value of Acorn Group plc was worth less than the value of its 24% holding in ARM. This situation led shareholders to press Acorn to sell its stake in ARM to provide a return on their investment. The situation also led ARM to consider taking action itself since a financially weak shareholder such as Acorn was putting ARM in a vulnerable position.
Acorn Computers Group plc was purchased on 1 June 1999 by Morgan Stanley Dean Witter Investments Limited. The transaction involved the de-listing of Acorn Group plc, as a result of which its shareholding in ARM was distributed to Acorn's shareholders.
On 26 July 1999, MSDW sold Acorn’s DSP business, Element 14, to an Acorn management team led by Stan Boland for £1.5 million – its net asset value. The set-top box division was acquired by Pace for £200,000. Pace thereby acquired control of RISC OS.
Element 14 continued to develop its DSP products until it was purchased by Broadcom in November 2000 for £366 ($594) million.
RISC OS
The operating system developed for Phoebe (RISC OS 4, codename Ursula) was made available to Risc PC users by RISCOS Ltd, which licensed the operating system, and continues to develop, support and sell RISC OS today.
However, the market is still competitive with two strands of the OS currently being developed, the 26bit RISC OS 4 which is currently sold for the Microdigital Omega, and the 32bit RISC OS 5 for the Castle Iyonix. This competition recently caused a crisis in the community, one that threatened the platform's existence.
See also
Footnotes
- "do it right" - quotation from an email from Sophie Wilson.
References
- Personal Computer World review of the BBC Micro (including details of BBC contract), December 1981 Personal Computer World
- "ARM's Way" (LISA influence, Berkeley RISC, Fabrication date), April 1988, Electronics Weekly
- "The history of the ARM CPU", taken from 'The ARM RISC Chip: A Programmers' Guide' by Carol Atack and Alex van Someren, published 1993 by Addison-Wesley.
- "From Atom to ARC - The ups and downs of the development of Acorn", from October, November and December 1988 editions of Acorn User.
- "ARM’s Race to Embedded World Domination" (Motorola 68000 was considered as a replacement to 6502), Paul DeMone, 2000
- "Sophie Wilson's most admired CPU" (32016 chip as example of "how to completely make a mess of things), Sophie Wilson
- Flotation of Acorn on Unlisted Securities Market, Electronics Times, 6 October 1983
External links
- The Acorn Atom pre-history
- RISC OS and Acorn pages
- Atom Review documentation of the Atom and lots of extensions made by Dutch Atom clubs
- About Acorn computers and ARM processors