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The BBC Microcomputer System was a series of Microcomputer s and associated Peripherals designed and built by Acorn Computers Ltd for the ''BBC Computer Literacy Project'' operated by the British Broadcasting Corporation . While twelve models were eventually produced in the range, the term BBC Micro is often colloquially used to refer to the first four (Model A, B, B+64 and B+128), with the later eight models referred to by the BBC Master and Archimedes names. BACKGROUND In the early 1980s , the BBC started what became known as the ''BBC Computer Literacy Project''. The project was initiated partly in response1 to an extremely influential ITV documentary series ''The Mighty Micro'', in which Dr Christopher Evans from the National Physical Laboratory predicted the coming (micro) Computer revolution and its impact on the economy, industry, and lifestyle of the United Kingdom . The BBC wanted to base its project on a Microcomputer capable of performing various tasks which they could then demonstrate in their 1981 TV series '' The Computer Programme ''. The list of topics included Programming , Graphics , sound and music, Teletext , controlling external hardware, Artificial Intelligence , etc. It decided to badge a micro, then drew up a fairly ambitious (for its time) specification and asked for takers. The BBC discussed the issue with Sir Clive Sinclair , who tried to offer the unsuccessful Grundy NewBrain micro to them, but it was rejected. The BBC made appointments to see several other British computer manufacturers, including Dragon and Acorn . The Acorn team had already been working on an upgrade to their existing '' Atom '' microcomputer. Known as the ''Proton'', it included better graphics and a faster 2 MHz MOS Technology 6502 CPU . The machine was only in prototype form at the time, but the Acorn team, largely made up of students including Roger Wilson and Steve Furber , worked through the night to get a working Proton together to show the BBC. The Acorn Proton not only was the only machine to come up to the BBC's specification, but also exceeded it in nearly every parameter. MARKET IMPACT The machine was released as the BBC Microcomputer in late 1981 and became affectionately known as the ''Beeb''. The machine was popular in the UK, especially in the educational market. As with Sinclair 's ZX Spectrum , also released later in 1982 , demand greatly exceeded supply. For some months, there were long delays before customers received the machines they had ordered. A brief attempt to market the machine in the United States failed, due largely to the predominance of the highly similar Apple II Family . The success of the machine in the UK was largely due to its acceptance as an "educational" computer – the vast majority of UK schools used BBC Micros to teach Computer Literacy and Information Technology skills. Some British Commonwealth countries, like India, started their own Computer Literacy programs and used the BBC Micro.2 Research Machines had, until this time, been one of the leaders in UK educational computer market. One of the main advantages which helped the BBC Micro in the educational market was its durable construction. The machine's casing and keyboard was solidly built compared to that of the ZX Spectrum, being able to cope with all the abuse that schoolchildren could throw at it. The Model A and the '''Model B''' were initially priced at £235 and £335 respectively, but rising almost immediately to £299 and £399 due to increased costs.http://www.stairwaytohell.com/articles/cr-BBCMicro-CToday.html Acorn anticipated the total sales to be around 12,000 units, but eventually more than 1 million BBC Micros were sold. The cost of the BBC Models was high compared to competitors such as the ZX Spectrum and Acorn attempted to counter this by producing a cut down version (although it did have the 32 kB RAM of the Model B rather than the 16 kB of the Model A), intended more for game playing, the Acorn Electron in 1983 ; games written specially for the Electron's more limited hardware could usually also be run on the Model B. DESCRIPTION Hardware features, Models A and B The Model A had 16 KB of user RAM; the Model B had 32 KB of user RAM. A feature of the 6502-based hardware that the Micro shared with other 6502 computers such as the Apple and the early Commodore models was that the RAM was clocked twice as fast as the CPU (4 MHz ), with alternating access given to the CPU and the video display circuits. This gave the BBC Micro a fully unified memory address structure with no speed penalties. Most competing Z80-based micros with memory mapped display incurred CPU speed penalties depending on the actions of the video circuits (e.g. the Amstrad CPC and to a lesser extent the ZX Spectrum ) or kept video memory completely separate from the CPU address pool (e.g. the MSX ). The machine included a number of extra '' (see below) and a CAD package which required a second 6502 CPU and a 5 dimensional joystick called a "Bitstick". The Model A and the Model B were built on the same PCB and a Model A could be upgraded to a Model B without too much difficulty. Users wishing to run Model B software needed only to add the extra RAM and the user/printer 6522 VIA (which many games used for timers etc) and snip a link, a task which could be achieved without soldering. To do a full upgrade with all the external ports did however require soldering the connectors to the motherboard. An apparent oversight in the manufacturing process resulted in a significant number of Model Bs producing a constant buzzing noise from the built-in speaker. This fault could be partly rectified by a Soldering -capable person, by soldering a resistor across two pads.http://www.sprow.co.uk/bbc/doctor.htm#bzzzt Hardware features: B+64 and B+128 Acorn introduced the Model B+ in mid 1985, increasing the total RAM to 64 KB and including floppy disk support as standard, but this had modest market impact. The extra RAM in the Model B+ BBC Micro was assigned as two blocks, a block of 20 KB dedicated solely for screen display (so-called " Shadow " RAM) and a block of 12 KB of 'special' Sideways RAM. The much-needed memory increase provided by this new 1985 'Beeb' was a welcome development, but was seen as an eighteen months or so too late to challenge the increased specifications of new rival microcomputer systems. The B+128 came with an additional 64 KB ( 4 × 16 KB "Sideways" RAM banks) to give a total RAM of 128 KB. The new B+ was incapable of running some original BBC B programs and games, such as, for example, the very popular ''Castle Quest''. A particular problem was the replacement of the Intel 8271 Floppy Disk controller with the Western Digital 1770 — many game software programmers in particular had used Copy Protection techniques which involved direct access to the controller, and simply wouldn't run on the new system. There was also a long-running problem late on in the B/B+'s life infamous amongst B+ owners, when Superior Software released ''Repton Infinity'', which refused to run on the B+. A string of unsuccessful replacements were issued before one compatible with both was finally released. Software and expandability ''.]] Large numbers of games were written for the Beeb, including the original version of the classic '' Elite ''. A range of hardware add-ons and expansions was available, and the machine had provisions for Floppy Disk drives and Econet networking hardware. There were also sockets for the addition of extra ROM chips. The built-in ROM-resident BBC BASIC programming language Interpreter was by far the most sophisticated of its time, and wholly supported the machine's educational focus. Advanced programs could be written without having to wade into the jungle of Assembly Language programming (necessary with many competing computers). Should one want, or need, to do some assembly programming, BBC BASIC featured a built-in assembler. When the BBC Micro was released competing PCs used Microsoft BASIC, or variants typically designed to resemble Microsoft BASIC. BBC Basic had the following advantages:
Although appropriate content was little-supported by television broadcasters, Telesoftware could be downloaded via the optional Teletext Adapter and the other alternative teletext adaptors that emerged. As the early BBC Micros had ample I/O allowing machines to be interconnected, and as many schools and universities employed the machines in Econet networks, numerous networked multiplayer games were created. With the exception of a Nethack game and a tank game ( Bolo , for example), few rose to popularity; in no small measure due to the limited number of machines aggregated in one place. It has been suggested, but not verified, that the world's first networked multiplayer game was written for the BBC computer, a strategy wargame of some kind. A relatively late but well documented example can be found in a dissertation based on a ringed RS-423 interconnect.http://bishop.mc.duke.edu/bolo/guides/dissertation/ SUCCESSOR MACHINES AND THE RETRO SCENE In 1986 , Acorn followed up with the BBC Master series, which offered memory sizes from 128 KB and many other refinements which improved on the 1981 original. It attracted more interest than the B+ upgrades, although at heart it was essentially the same 6502-based BBC architecture, with many of the upgrades that the original design had intentionally made possible (extra ROM software, extra paged RAM, second processors) now included on the circuit board. However, Acorn had produced their own 32-bit RISC CPU in 1985 and were working on building a personal computer around it. This was released in 1987 as four models in the Archimedes series, with the lower-specified two models (with 512 KB and 1 MiB respectively) released as BBC Microcomputers. The last model, the BBC A3000, was released in 1989 as essentially a 1 MiB Archimedes back in a single case Form Factor . The BBC closed the Computer Literacy Project two years later. As Of 2005 , thanks to its ready expandability and I/O functions, there are still numbers of BBCs in use, and a Retrocomputing community of dedicated users finding new things to do with the old hardware. A BBC B+ was observed running the communications link in an unattended water pumping station in Oxhey in 1995. They still survive in a few interactive displays in museums across the country (often with no maintenance since they were first built). There are also a number of BBC Micro Emulator s for many OSes, so that even the original hardware is no longer necessary. SPECIFICATIONS (MODEL A TO MODEL B+128) The case was designed by industrial designer Allen Boothroyd of Cambridge Product Design Ltd. Display modes
Optional extras
TRIVIA
SEE ALSO NOTES EXTERNAL LINKS
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