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94-739: The BBC Microcomputer System , or BBC Micro , is a series of microcomputers designed and built by Acorn Computers Limited in the 1980s for the Computer Literacy Project of the BBC . The machine was the focus of a number of educational BBC TV programmes on computer literacy, starting with The Computer Programme in 1982, followed by Making the Most of the Micro , Computers in Control in 1983, and finally Micro Live in 1985. After

188-578: A microcomputer capable of performing various tasks which they could then demonstrate in the TV series The Computer Programme . The list of topics included programming , graphics , sound and music, teletext , controlling external hardware, and artificial intelligence . It developed an ambitious specification for a BBC computer, and discussed the project with several companies including Acorn Computers , Sinclair Research , Newbury Laboratories, Tangerine Computer Systems , and Dragon Data . The introduction of

282-481: A power supply . The two processors communicate through four pairs of FIFO buffers in the Tube ULA. Console input/output, error messages , data transfers and system calls each have their own pair of buffers, one for each direction. The queue capacity varies between 1 and 24 bytes, depending on the dedicated buffer function. Each buffer has a control register and status register to monitor its state and configure

376-478: A "Bitstik" [1] . The Model A and the Model B were built on the same printed circuit board (PCB), and a Model A can be upgraded to a Model B. Users wishing to operate Model B software need to add the extra RAM and the user/printer MOS Technology 6522 VIA (which many games use for timers) and snip a link, a task that can be achieved without soldering. To do a full upgrade with all the external ports requires soldering

470-557: A "low-cost development" of an existing machine, the Transam Tuscan, which included dual floppy drives and cost £1,700. This proposal was voted down by the ITV companies, citing a possible contravention of the companies' obligations under broadcasting regulations prohibiting sponsorship, along with concerns about a conflict of interest with advertisers of computer products. Despite denials of involvement with ITV from Prism Microproducts,

564-599: A BBC Micro clone called the Dolphin. Unlike the original BBC Micro, the Dolphin featured blue function keys. Production agreements were made with both SCL in India and distributor Harry Mazal in Mexico for the assembly of BBC Micro units from kits of parts, leading to full-scale manufacturing, with SCL also planning to fabricate the 6502 CPU under licence from Rockwell. According to reporting from early 1985, "several thousand Beebs

658-705: A Z80 board and hard disk drive from Torch that allowed the BBC machine to run CP/M programs. Separate pages, each with a codename, are used to control the access to the I/O: The Tube interface allowed Acorn to use BBC Micros with ARM CPUs as software development machines when creating the Acorn Archimedes . This resulted in the ARM development kit for the BBC Micro in 1986, priced at around £4000. From 2006,

752-495: A broadcast quality signal for use within television programming; it was used on episodes of The Computer Programme and Making the Most of the Micro . The computer included several input/output (I/O) interfaces: serial and parallel printer ports, an 8-bit general purpose digital I/O port, a port offering four analogue inputs, a light pen input, and an expansion connector (the "1 MHz bus") which enabled other hardware to be connected. An Econet network interface and

846-595: A computer based on a microprocessor – the Intel 8008 8-bit microprocessor. This Micral-N was marketed in early 1973 as a "Micro-ordinateur" or microcomputer , mainly for scientific and process-control applications. About a hundred Micral-N were installed in the next two years, followed by a new version based on the Intel 8080. Meanwhile, another French team developed the Alvan, a small computer for office automation which found clients in banks and other sectors. The first version

940-463: A computer had to be big in size to be powerful, and thus decided to market them as calculators. Additionally, at that time, people were more likely to buy calculators than computers, and, purchasing agents also preferred the term "calculator" because purchasing a "computer" required additional layers of purchasing authority approvals. The Datapoint 2200 , made by CTC in 1970, was also comparable to microcomputers. While it contains no microprocessor,

1034-585: A computer retailing strategy. A key feature of the BBC Micro's design is the high-performance random-access memory (RAM) it is equipped with. A common design note in 6502 -based computers of the era was to run the RAM at twice the clock rate as the CPU. This allowed a separate video display controller to access memory while the CPU was busy processing the data just read. In this way, the CPU and graphics driver could share access to RAM through careful timing. This technique

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1128-400: A disk drive interface were available as options. All motherboards had space for the electronic components, but Econet was rarely installed. Additionally, an Acorn proprietary interface named the " Tube " allowed a second processor to be added. Three models of second processor were offered by Acorn, based on the 6502 , Z80 and 32016 CPUs. The Tube was used for third-party add-ons, including

1222-422: A disk operating system included in a series of programmable read-only memory chips (PROMs); 8 Kilobytes of RAM; IBM's Basic Assembly Language (BAL); a hard drive; a color display; a printer output; a 150 bit/s serial interface for connecting to a mainframe; and even the world's first microcomputer front panel. In early 1973, Sord Computer Corporation (now Toshiba Personal Computer System Corporation ) completed

1316-506: A dummy byte and then regulated by the relevant buffer semaphore. The general-purpose nature of the Tube connector in principle allows it to be used for any type of high-speed peripheral, although Acorn only uses it for Tube coprocessors. The BBC Micro/Master range provides 5 address lines for the address range &60–&7F but the Tube protocol uses the lowest 3 bits. Only these 3 address lines are connected to internal Tube sockets, as found in

1410-440: A finger on a certain place on the motherboard caused the prototype to work. Acorn put a resistor pack across the data bus, which Furber described as " 'the engineer's finger' and again, we have no idea why it's necessary, and a million and a half machines later it's still working, so nobody asked any questions". The Model A shipped with 16  KB of user RAM, while the Model B had 32 KB. Extra ROMs could be fitted (four on

1504-402: A given price, none of them surpass the BBC ... in terms of versatility and expansion capability". As with Sinclair Research 's ZX Spectrum and Commodore International 's Commodore 64 , both released the next year, in 1982, demand greatly exceeded supply. For some months, there were long delays before customers received the machines they had ordered. Efforts were made to market the machine in

1598-459: A kit with an ARM7TDMI CPU running at 64 MHz, with as much as 64 MB of RAM, was released for the BBC Micro and Master, using the Tube interface to upgrade the 8-bit micros to 32-bit RISC machines. Among the software that operated on the Tube are an enhanced version of the Elite video game and a computer-aided design system that required a second 6502 CPU and a 3-dimensional joystick named

1692-419: A minicomputer or time-sharing service the opportunity to automate business functions, without (usually) hiring a full-time staff to operate the computers. A representative system of this era would have used an S100 bus , an 8-bit processor such as an Intel 8080 or Zilog Z80 , and either CP/M or MP/M operating system. The increasing availability and power of desktop computers for personal use attracted

1786-450: A month" were being produced in India. Meanwhile, the eventual production arrangement in Mexico involved local manufacturer Datum (a company founded by Harry Mazal and others, initially to act as ICL's Mexican distributor), aiming to assemble 2000 units per month by May 1985, with the initial assembly intended to lead to the manufacture of all aspects of the machines apart from Acorn's proprietary ULA components. Such machines were intended for

1880-684: A solid state machine designed with a microprocessor. In the US the earliest models such as the Altair 8800 were often sold as kits to be assembled by the user, and came with as little as 256 bytes of RAM , and no input/output devices other than indicator lights and switches, useful as a proof of concept to demonstrate what such a simple device could do. As microprocessors and semiconductor memory became less expensive, microcomputers grew cheaper and easier to use. All these improvements in cost and usability resulted in an explosion in their popularity during

1974-505: A specific microcomputer to a more general computer literacy initiative was a topic of controversy, however, with criticism aimed at the BBC for promoting a specific commercial product and for going beyond the "traditional BBC pattern" of promoting existing information networks of training and education providers. Accusations were even levelled at the Department of Industry for making the BBC "an arm of Government industrial policy" and using

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2068-484: A stop gap", and others criticising the elevated price of £500 (compared to the £400 of the original Model B) in the face of significantly cheaper competition providing as much or even twice as much memory. The extra RAM in the Model B+ is 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 B+128, introduced towards

2162-557: A time, although they can often be modified with software or hardware to concurrently serve more than one user. Microcomputers fit well on or under desks or tables, so that they are within easy access of users. Bigger computers like minicomputers , mainframes , and supercomputers take up large cabinets or even dedicated rooms. A microcomputer comes equipped with at least one type of data storage, usually RAM . Although some microcomputers (particularly early 8-bit home micros) perform tasks using RAM alone, some form of secondary storage

2256-579: Is also a long-running problem late in the B/B+'s commercial life infamous amongst B+ owners, when Superior Software released Repton Infinity , which did not run on the B+. A series of unsuccessful replacements were issued before one compatible with both was finally released. During 1986, Acorn followed up with the BBC Master , which offers memory sizes from 128 KB and many other refinements which improved upon

2350-403: Is fundamentally incompatible, and the 8271 emulators that existed were necessarily imperfect for all but basic operation. Software that use copy protection techniques involving direct access to the controller do not operate on the new system. Acorn attempted to alleviate this, starting with version 2.20 of the 1770 DFS, via an 8271-backward- compatible Ctrl + Z + Break option. There

2444-469: Is limited). The Tube was also used during the initial development of the ARM processor. An evaluation board was developed that again uses the BBC Micro as a host system for I/O operations. Before shipping Tube add-ons, Acorn had strongly discouraged BBC Micro programmers from directly accessing system memory and hardware, favouring official API calls. This was to ensure applications can be seamlessly moved to

2538-806: Is normally desirable. In the early days of home micros, this was often a data cassette deck (in many cases as an external unit). Later, secondary storage (particularly in the form of floppy disk and hard disk drives) were built into the microcomputer case. Although they did not contain any microprocessors, but were built around transistor-transistor logic (TTL), Hewlett-Packard calculators as far back as 1968 had various levels of programmability comparable to microcomputers. The HP 9100B (1968) had rudimentary conditional (if) statements, statement line numbers, jump statements ( go to ), registers that could be used as variables, and primitive subroutines. The programming language resembled assembly language in many ways. Later models incrementally added more features, including

2632-534: Is sometimes called the first generation of microcomputers. Many companies such as DEC , National Semiconductor , Texas Instruments offered their microcomputers for use in terminal control, peripheral device interface control and industrial machine control. There were also machines for engineering development and hobbyist personal use. In 1975, the Processor Technology SOL-20 was designed, which consisted of one board which included all

2726-653: The 32016 Second Processor featured a National Semiconductor 32016 processor running Panos . These coprocessors formed the basis of the Acorn Business Computer series, the higher end machines being repackaged BBC Micros with a coprocessor attached via the Tube. The Master Series supports two Tube connections, allowing for a coprocessor fitted inside the case and another connected externally, but only one can be used in any powered session. An internal 6502 processor can be fitted, or an Intel 80186 based system for DOS compatibility (although in practice this

2820-406: The Acorn Business Computer (ABC)/Acorn Cambridge Workstation range of machines was announced, based primarily on BBC hardware. In mid-1985, Acorn introduced the Model B+ which increased the total RAM to 64 KB. This had a modest market impact and received a rather unsympathetic reception, with one reviewer's assessment being that the machine was "18 months too late" and that it "must be seen as

2914-450: The BASIC programming language (HP 9830A in 1971). Some models had tape storage and small printers. However, displays were limited to one line at a time. The HP 9100A was referred to as a personal computer in an advertisement in a 1968 Science magazine, but that advertisement was quickly dropped. HP was reluctant to sell them as "computers" because the perception at that time was that

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3008-664: The ITV network to introduce their own initiative and rival computing system, with a CP/M-based system proposed by Transam Computers under consideration for such an initiative by the Independent Television Companies Association at a late 1983 meeting. The proposed machine would have been priced at £399, matching that of the BBC Model B, and was reported as offering 64 KB of RAM, a disc interface, and serial and parallel interfaces, itself being

3102-488: The Tube interface was incorporated into the design, enabling a Z80 second processor to be added. A new contract between Acorn and BBC Enterprises was agreed in 1984 for another four-year term, with other manufacturers having tendered for the deal. An Acorn representative admitted that the BBC Model B would not be competitive throughout the term of the renewed contract, and that a successor would emerge. The OS ROM v1.0 contains

3196-566: The instruction set of its custom TTL processor was the basis of the instruction set for the Intel 8008 , and for practical purposes the system behaves approximately as if it contains an 8008. This is because Intel was the contractor in charge of developing the Datapoint's CPU, but ultimately CTC rejected the 8008 design because it needed 20 support chips. Another early system, the Kenbak-1 ,

3290-460: The 1981 original. It has essentially the same 6502-based BBC architecture, with many of the upgrades that the original design intentionally makes possible (extra ROM software, extra paged RAM, second processors) now included on the circuit board as internal plug-in modules. The BBC Micro platform amassed a large software base of both games and educational programs for its two main uses as a home and educational computer. Notable examples of each include

3384-546: The 6502 can translate the request for the local machine or send it across the Tube interface, as direct access is impossible from the coprocessor. Published programs largely conform to the API except for games, which routinely engage with the hardware for greater speed, and require a particular Acorn model. Microcomputer The abbreviation "micro" was common during the 1970s and 1980s, but has since fallen out of common usage. The term microcomputer came into popular use after

3478-549: The Altair itself was only a mild commercial success, it helped spark a huge industry. By 1977, the introduction of the second microcomputer generation as consumer goods , known as home computers , made them considerably easier to use than their predecessors because their predecessors' operation often demanded thorough familiarity with practical electronics. The ability to connect to a monitor (screen) or TV set allowed visual manipulation of text and numbers. The BASIC language, which

3572-579: The BASIC III ROM chip, modified to accept the American spelling of COLOR , but the height of the graphics display was reduced to 200 scan lines to suit NTSC TVs, severely affecting applications written for British computers. After the failed US marketing campaign, the unwanted machines were remanufactured for the British market and sold, resulting in a third export variant. In October 1984,

3666-512: The BBC Master or Universal Second Processor Unit. Numerous coprocessors were developed for the Tube. Most commonly seen was the 6502 Second Processor , featuring a MOS Technology 6502 processor, which allowed unmodified BBC Micro programs to run faster and with more memory, as long as they use the API for all I/O. The Z80 Second Processor featured a Zilog Z80 processor running CP/M , and

3760-401: The BBC Micro system" for which 200 educational titles were being offered. In October 1984, while preparing a major expansion of its US dealer network, Acorn claimed sales of 85 per cent of the computers in British schools, and delivery of 40,000 machines per month. That December, Acorn stated its intention to become the market leader in US educational computing. The New York Times considered

3854-597: The BBC Models was high compared to competitors such as the ZX Spectrum and the Commodore 64, and from 1983 on, Acorn attempted to counter this by producing a simplified but largely compatible version intended for home use, complementing the use of the BBC Micro in schools: the 32K Acorn Electron . The involvement of the BBC in microcomputing also initiated tentative plans by the independent television companies of

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3948-602: The BBC started what became known as the BBC Computer Literacy Project . The project was initiated partly in response to an ITV documentary series The Mighty Micro , in which Christopher Evans of the UK's National Physical Laboratory predicted the coming microcomputer revolution and its effect on the economy, industry, and lifestyle of the United Kingdom. The BBC wanted to base its project on

4042-563: The Computer Literacy Project as a way of "funding industry through the back door", obscuring public financial support on behalf of a government that was ostensibly opposed to subsidising industry. The Acorn team had already been working on a successor to their existing Atom microcomputer. Known as the Proton , it included better graphics and a faster 2 MHz MOS Technology 6502 central processing unit . The machine

4136-623: The IBM PC itself was widely imitated, as well as the term. The component parts were commonly available to producers and the BIOS was reverse engineered through cleanroom design techniques. IBM PC compatible "clones" became commonplace, and the terms "personal computer", and especially "PC", stuck with the general public, often specifically for a computer compatible with DOS (or nowadays Windows). Monitors, keyboards and other devices for input and output may be integrated or separate. Computer memory in

4230-520: The Literacy Project's call for bids for a computer to accompany the television programmes and literature, Acorn won the contract with the Proton , a successor of its Atom computer prototyped at short notice. Renamed the BBC Micro, the system was adopted by most schools in the United Kingdom , changing Acorn's fortunes. It was also successful as a home computer in the UK, despite its high price compared to some other home computers sold in

4324-526: The Mexican and South American markets, potentially also appealing to those south-western states of the US having large Spanish-speaking populations. Ultimately, upon Acorn's withdrawal from the US in 1986, Datum would continue manufacturing at a level of 7000 to 8000 Spanish-language machines per year for the North and South American markets. The initial strategy for the BBC's computer literacy endeavour involved

4418-516: The PCB or sixteen with expansion hardware) and accessed via paged memory . The machines included three video ports, one with an RF modulator sending out a signal in the UHF band, another sending composite video suitable for connection to computer monitors , and a separate RGB video port. The separate RGB video out socket was an engineering requirement from the BBC to allow the machine to directly output

4512-474: The Proton was the only machine to match the BBC's specification; it also exceeded the specification in nearly every parameter. Based on the Proton prototype, the BBC signed a contract with Acorn as early as February 1981; by June the BBC Micro's specifications and pricing were decided. As a concession to the BBC's expectation of "industry standard" compatibility with CP/M, apparently under the direction of John Coll,

4606-536: The RAM had to allow four million access cycles per second. Hitachi was the only company considering a DRAM which ran at that speed, the HM4816. To equip the prototype machine, the only four 4816s in the country were hand-carried by the Hitachi representative to Acorn. The National Semiconductor 81LS95 multiplexer was needed for the high memory speed. Furber recalled that competitors came to Acorn offering to replace

4700-702: The SMP80/08, which used the Intel 8008 microprocessor. The SMP80/08, however, did not have a commercial release. After the first general-purpose microprocessor, the Intel 8080 , was announced in April 1974, Sord announced the SMP80/x, the first microcomputer to use the 8080, in May 1974. Virtually all early microcomputers were essentially boxes with lights and switches; one had to read and understand binary numbers and machine language to program and use them (the Datapoint 2200

4794-487: The Tube 6502 coprocessor, since direct access from there is impossible. When a program calls one of the MOS entry points, a replacement subroutine in the coprocessor's ROM passes a corresponding message to the host which carries out the operation and passes back the result. In this way an application can run identically on the host or the coprocessor. Other CPU models use a custom API, which is typically an orthogonal translation of

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4888-402: The UK at the time. Acorn later employed the machine to simulate and develop the ARM architecture . While nine models were eventually produced with the BBC brand, the phrase "BBC Micro" is usually used colloquially to refer to the first six (Model A, B, B+64, B+128, Master 128, and Master Compact); subsequent BBC models are considered part of Acorn's Archimedes series. During the early 1980s,

4982-575: The United States and West Germany. Acorn's strategy in the US focused on the education market, worth a reported $ 700 million , by offering the BBC Micro in an upgraded form of the Model B with an expanded ROM, speech synthesis hardware, and built-in Econet interface for a price of $ 995, complementing this with the provision of software and materials designed to support teaching and to encourage adoption by teachers "fearful" of computers or skeptical of

5076-522: The attached device. Inside the coprocessor unit a proprietary chip (the Tube ULA , manufactured initially by Ferranti ) interfaces and logically isolates the host and coprocessor buses . This allows the Tube to work with a completely different bus architecture in the coprocessor unit. The other active components needed are a microprocessor , some RAM , a small ROM containing processor specific client code, glue logic such as an address decoder and

5170-439: The attention of more software developers. As the industry matured, the market for personal computers standardized around IBM PC compatibles running DOS , and later Windows . Modern desktop computers, video game consoles , laptops , tablet PCs , and many types of handheld devices , including mobile phones , pocket calculators , and industrial embedded systems , may all be considered examples of microcomputers according to

5264-501: The command line. The MOS recognises certain built-in commands, and polls the paged ROMs in descending order for service otherwise; if none of them claims the command, then the OS returns a Bad command error. Suitable ROM (or EPROM) images could be written and provide functions without requiring RAM for the code itself. Not all ROMs offer star commands (ROMs containing data files, for instance), but any ROM can " hook " into vectors to enhance

5358-556: The company had already been pursuing a joint venture with Transam on a product rumoured to be under consideration by the broadcasting group. This product, a business system subsequently known as the Wren, had reportedly been positioned as such an "ITV Micro" towards the end of 1983, also to be offered in a home variant with ORACLE teletext reception capabilities. However, not all ITV franchise holders were equally enthusiastic about scheduling programmes related to microcomputing or about pursuing

5452-527: The competition from IBM, Apple , and Commodore. Another deployment in Phoenix, Arizona valued at $ 174,697 saw 175 BBC Micros installed, with the local Acorn dealer predicting sales worth $ 2 million in the next two years, of which around 85 to 90 percent would be made into education, the remainder going to the small business market. In early 1984, Acorn claimed a US network of more than 1,000 dealers, also reporting "over $ 50 million worth of education orders for

5546-498: The component with their own, but "none of them worked. And we never knew why. Which of course, means we didn't know why the National Semiconductor one did work correctly. And a million and a half BBC Micros later, it was still working, and I still didn't know why". Another mystery was the 6502's data bus . The prototype BBC Micro exceeded the CPU's specifications, causing it to fail. The designers found that putting

5640-482: The connectors to the motherboard. The original machines shipped with "OS 0.1", with later updates advertised in magazines, supplied as a clip-in integrated circuit, with the last official version being "OS 1.2". Variations in the Acorn OS exist as a result of home-made projects and modified machines can still be bought on Internet auction sites such as eBay as of 2011. The BBC Model A was phased out of production with

5734-520: The definition given above. By the early 2000s, everyday use of the expression "microcomputer" (and in particular "micro") declined significantly from its peak in the mid-1980s. The term is most commonly associated with the most popular 8-bit home computers (such as the Apple II , ZX Spectrum , Commodore 64 , BBC Micro , and TRS-80 ) and small-business CP/M -based microcomputers. In colloquial usage, "microcomputer" has been largely supplanted by

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5828-402: The details of the technical changes. Per Watford Electronics comments in their '32K Ram Board Manual': Early issue BBCs (Issue 3 circuit boards and before) are notorious for out of specification timings. If problems occur with this sort of machine, the problem can generally be cured by the use of either a Rockwell 6502A CPU chip, or by replacing IC14 (a 74LS245) with either another 74LS245 or

5922-490: The end of 1985, comes with an additional 64 KB (4 × 16 KB sideways RAM banks) to give a total RAM of 128 KB. The B+ is incapable of operating some original BBC B programs and games, such as the very popular Castle Quest . A particular problem is the replacement of the Intel 8271 floppy-disk controller with the Western Digital 1770 : not only was the new controller mapped to different addresses, it

6016-470: The faster 74ALS245. Two export models were developed: one for the US, with Econet and speech hardware as standard; the other for West Germany . Despite concerns of unsuitability for the Australian market, with the design failing at temperatures above 35 °C (95 °F), the machine was still "widely used in Australian schools". Export models were fitted with radio frequency shielding as required by

6110-595: The following ASCII credits string (code here ): Additionally, the last bytes of the BASIC read-only memory (ROM; v2 and v4) include the word "Roger", which is a reference to Sophie Wilson whose name at the time was Roger Wilson. The machine was released as the BBC Microcomputer on 1 December 1981, although production problems pushed delivery of the majority of the initial run into 1982. Nicknamed "the Beeb", it

6204-452: The form of RAM , and at least one other less volatile, memory storage device are usually combined with the CPU on a system bus in one unit. Other devices that make up a complete microcomputer system include batteries, a power supply unit, a keyboard and various input/output devices used to convey information to and from a human operator ( printers , monitors , human interface devices ). Microcomputers are designed to serve only one user at

6298-687: The inclusion of local area networking to be of prime importance to teachers. The operation resulted in advertisements by at least one dealer in Interface Age magazine, but ultimately the attempt failed. The success of the machine in the UK was due largely to its acceptance as an "educational" computer – UK schools used BBC Micros to teach computer literacy , information technology skills. Acorn became more known for its BBC Model B computer than for its other products. Some Commonwealth countries, including India , started their own computer literacy programmes around 1984. Intending to avoid "re-inventing

6392-653: The inherent performance hit, as was the case for the Amstrad CPC , Atari 8-bit computers , and to a lesser extent the ZX Spectrum . Others, like the MSX systems, used entirely separate pools of memory for the CPU and video, slowing access between the two. Furber believed that the Acorn design should have a flat memory model and allow the CPU and video system to access the bus without interfering with each other. To do so,

6486-533: The introduction of the Acorn Electron , with chairman Chris Curry stating at the time that Acorn "would no longer promote it" (the Model A). Early BBC Micros used linear power supplies at the insistence of the BBC, which, as a broadcaster, was cautious about electromagnetic interference . The supplies were unreliable, and after a few months the BBC allowed switched-mode units. An apparent oversight in

6580-629: The introduction of the minicomputer , although Isaac Asimov used the term in his short story " The Dying Night " as early as 1956 (published in The Magazine of Fantasy and Science Fiction in July that year). Most notably, the microcomputer replaced the many separate components that made up the minicomputer's CPU with one integrated microprocessor chip . In 1973, the French Institut National de la Recherche Agronomique (INRA)

6674-513: The keyboard, with the leftmost socket hard-wired for the OS. The intended purpose for the perforated panel on the left of the keyboard was for a Serial ROM or Speech ROM. The paged ROM system is essentially modular. A language-independent system of star commands , prefixed with an asterisk, provides the ability to select a language (for example *BASIC , *PASCAL ), a filing system ( *TAPE , *DISC ), change settings ( *FX , *OPT ), or carry out ROM-supplied tasks ( *COPY , *BACKUP ) from

6768-581: The late 1970s and early 1980s. A large number of computer makers packaged microcomputers for use in small business applications. By 1979, many companies such as Cromemco , Processor Technology , IMSAI , North Star Computers , Southwest Technical Products Corporation , Ohio Scientific , Altos Computer Systems , Morrow Designs and others produced systems designed for resourceful end users or consulting firms to deliver business systems such as accounting, database management and word processing to small businesses. This allowed businesses unable to afford leasing of

6862-460: The manufacturing process resulted in many Model Bs producing a constant buzzing noise from the built-in speaker. This fault can be rectified partly by soldering a resistor across two pads. There are five developments of the main BBC Micro circuit board that addressed various issues through the model's production, from 'Issue 1' through to 'Issue 7' with variants 5 and 6 not being released. The 1985 'BBC Microcomputer Service Manual' from Acorn documents

6956-492: The marketing of the "Acorn Proton-based BBC microcomputer for less than £200". The Model A and the Model B were initially priced at £235 and £335 respectively, but increased almost immediately to £299 and £399 due to higher costs. The Model B price of nearly £400 was roughly £1200 (€1393) in 2011 prices – thirty years after its launch – or around £1900 today. Acorn anticipated total sales to be around 12,000 units, but eventually more than 1.5 million BBC Micros were sold. The cost of

7050-583: The original release of Elite and Granny's Garden . Programming languages and some applications were supplied on ROM chips to be installed on the motherboard. These load instantly and leave the RAM free for programs or documents. Although appropriate content was little-supported by television broadcasters, telesoftware could be downloaded via the optional Teletext Adapter and the third-party teletext adaptors that emerged. The built-in operating system, Acorn MOS , provides an extensive API to interface with all standard peripherals, ROM-based software, and

7144-468: The parts of the computer system. The SOL-20 had built-in EPROM software which eliminated the need for rows of switches and lights. The MITS Altair just mentioned played an instrumental role in sparking significant hobbyist interest, which itself eventually led to the founding and success of many well-known personal computer hardware and software companies, such as Microsoft and Apple Computer . Although

7238-405: The raising of interrupts . The protocol for the use of these buffers was rigorously specified by Acorn Computers and amounted to interprocess communication by message passing . Most interaction is asynchronous but fast block transfers are synchronous and consist of the host blindly running a simple fetch-store loop, which defines the transfer rate. The coprocessor is synchronised by passing

7332-542: The respective countries. From June 1983 the name was always spelled out completely – "British Broadcasting Corporation Microcomputer System" – to avoid confusion with Brown, Boveri & Cie in international markets, after warnings from the Swiss multinational not to market the computer with the BBC label in West Germany, thus forcing Acorn to relabel "hundreds of machines" to comply with these demands. US models include

7426-596: The role of computers in the curriculum. By October 1983, the US operation reported that American schools had placed orders with it totalling $ 21 million . In one deployment in Lowell, Massachusetts valued at $ 177,000, 138 BBC Micros were installed in eight of the 27 schools in the city, with the computer's networking capabilities, educational credentials, and the availability of software with "high education quality" accompanied by "useful lesson plans and workbooks" all given as reasons for selecting Acorn's machine in preference to

7520-568: The screen. Features specific to some versions of BASIC, like vector graphics , keyboard macros , cursor-based editing, sound queues, and envelopes , are in the MOS ROM and made available to any application. BBC BASIC itself, being in a separate ROM, can be replaced with another language. BASIC, other languages, and utility ROM chips reside in any of four 16 KB paged ROM sockets, with OS support for sixteen sockets via expansion hardware. The five (total) sockets are located partly obscured under

7614-472: The system variables and hardware, favouring official system calls . This was ostensibly to make sure programs keep working when migrated to coprocessors that utilise the Tube interface, but it also makes BBC Micro software more portable across the Acorn range. Whereas untrappable PEEKs and POKEs are used by other computers to reach the system elements, programs in either machine code or BBC BASIC instead pass parameters to an operating system routine. In this way,

7708-733: The system's functionality. Often the ROM is a device driver for mass storage combined with a filing system, starting with Acorn's 1982 Disc Filing System (DFS) which API became the de facto standard for floppy-disc access. The Acorn Graphics Extension ROM (GXR) expands the VDU routines to draw geometric shapes, flood fills, and sprites. During 1985, Micro Power designed and marketed a Basic Extension ROM, introducing statements such as WHILE , ENDWHILE , CASE , WHEN , OTHERWISE , ENDCASE , and direct mode commands including VERIFY . Acorn strongly discouraged programmers from directly accessing

7802-494: The term personal computer became generally used for microcomputers compatible with the IBM PC architecture ( IBM PC–compatible ). Tube (BBC Micro) In the BBC Microcomputer System , the Tube is the expansion interface and architecture which allows the BBC Micro to communicate with a second processor , or coprocessor . Under the Tube architecture, the coprocessor runs the application software for

7896-452: The term " personal computer " or "PC", which specifies a computer that has been designed to be used by one individual at a time, a term first coined in 1959. IBM first promoted the term "personal computer" to differentiate the IBM PC from CP/M -based microcomputers likewise targeted at the small-business market, and also IBM's own mainframes and minicomputers. However, following its release,

7990-551: The user, whilst the Micro (acting as a host ) provides all I/O functions, such as screen display, keyboard and storage devices management. A coprocessor unit can be coldplugged into any BBC Micro with a disk interface (whose ROM contained the necessary host software) and used immediately. The 40-pin IDC "Tube" connector is a simple slave connection to the host processor's main bus, with 8 data lines, 7 address lines, and an interrupt input. The Tube protocols are implemented by hardware in

8084-505: The wheel", such efforts adopted the BBC Micro in order to take immediate advantage of the extensive range of software already developed under the United Kingdom's own literacy initiative, proposing that software tailored for local requirements would ultimately also be developed. A clone of the BBC Micro was produced by Semiconductor Complex Limited and named the SCL Unicorn. Another Indian computer manufacturer, Hope Computers Pvt Ltd, made

8178-493: Was a striking exception, bearing a modern design based on a monitor, keyboard, and tape and disk drives). Of the early "box of switches"-type microcomputers, the MITS Altair 8800 (1975) was arguably the most famous. Most of these simple, early microcomputers were sold as electronic kits —bags full of loose components which the buyer had to solder together before the system could be used. The period from about 1971 to 1976

8272-535: Was based on LSI chips with an Intel 8008 as peripheral controller (keyboard, monitor and printer), before adopting the Zilog Z80 as main processor. In late 1972, a Sacramento State University team led by Bill Pentz built the Sac State 8008 computer, able to handle thousands of patients' medical records. The Sac State 8008 was designed with the Intel 8008. It had a full set of hardware and software components :

8366-474: Was easier to learn and use than raw machine language, became a standard feature. These features were already common in minicomputers , with which many hobbyists and early produces were familiar. In 1979, the launch of the VisiCalc spreadsheet (initially for the Apple II ) first turned the microcomputer from a hobby for computer enthusiasts into a business tool. After the 1981 release by IBM of its IBM PC ,

8460-479: Was looking for a computer able to measure agricultural hygrometry . To answer this request, a team of French engineers of the computer technology company R2E, led by its Head of Development, François Gernelle , created the first available microprocessor-based microcomputer, the Micral N. The same year the company filed their patents with the term "Micro-ordinateur", a literal equivalent of "Microcomputer", to designate

8554-473: Was only at the design stage at the time, and the Acorn team, including Steve Furber and Sophie Wilson , had one week to build a working prototype from the sketched designs. The team worked through the night to get a working Proton together to show the BBC. Although the BBC expected a computer with the Zilog Z80 CPU and CP/M operating system, not the Proton's 6502 CPU and proprietary operating system,

8648-478: Was popular in the UK, especially in the educational market; about 80% of British schools had a BBC microcomputer. Byte called the BBC Micro Model B "a no-compromise computer that has many uses beyond self-instruction in computer technology". It called the Tube interface "the most innovative feature" of the computer, and concluded that "although some other British microcomputers offer more features for

8742-429: Was released in 1971. Like the Datapoint 2200, it used small-scale integrated transistor–transistor logic instead of a microprocessor. It was marketed as an educational and hobbyist tool, but it was not a commercial success; production ceased shortly after introduction. In late 1972, a French team headed by François Gernelle within a small company, Réalisations & Etudes Electroniques (R2E), developed and patented

8836-464: Was used, for example, on the Apple II Plus and the early Commodore models. The BBC machine, however, was designed to run at the faster CPU speed, 2  MHz , double that of these earlier machines. In this case, bus contention is normally an issue, as there is not enough time for the CPU to access the memory during the period when the video hardware is idle. Some machines of the era accept

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