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110-527: 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 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

220-514: 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 : 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);

330-869: 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 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

440-478: 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

550-559: 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,

660-601: 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

770-463: 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 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

880-658: 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,

990-598: 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

1100-586: 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

1210-661: A consensus definition of a minicomputer as a machine costing less than US$ 25,000 (equivalent to $ 196,000 in 2023 ), with an input-output device such as a teleprinter and at least four thousand words of memory, that is capable of running programs in a higher level language, such as Fortran or BASIC . The class formed a distinct group with its own software architectures and operating systems. Minis were designed for control, instrumentation, human interaction, and communication switching as distinct from calculation and record keeping. Many were sold indirectly to original equipment manufacturers (OEMs) for final end-use application. During

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1320-400: 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

1430-586: A few proprietary minicomputer architectures survive. The IBM System/38 operating system, which introduced many advanced concepts, lives on with IBM's AS/400 . Great efforts were made by IBM to enable programs originally written for the IBM System/34 and System/36 to be moved to the AS/400. After being rebranded multiple times, the AS/400 platform was replaced by IBM Power Systems running IBM i . In contrast, competing proprietary computing architectures from

1540-441: 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

1650-541: 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 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,

1760-541: 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 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,

1870-511: 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

1980-419: 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

2090-451: 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

2200-470: A result, less expensive. They were used in manufacturing process control, telephone switching and to control laboratory equipment. In the 1970s, they were the hardware that was used to launch the computer-aided design (CAD) industry and other similar industries where a small dedicated system was needed. The boom in worldwide seismic exploration for oil and gas in the early 1970s saw the widespread use of minicomputers in dedicated processing centres close to

2310-486: 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

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2420-512: 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 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

2530-557: 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

2640-542: 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, 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

2750-579: 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

2860-511: 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 , 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

2970-406: 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

3080-806: 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

3190-448: Is seldom used today; the contemporary term for this class of system is " midrange computer ", such as the higher-end SPARC from Oracle , Power ISA from IBM , and Itanium -based systems from Hewlett-Packard . The term "minicomputer" developed in the 1960s to describe the smaller computers that became possible with the use of transistors and core memory technologies, minimal instructions sets and less expensive peripherals such as

3300-406: Is sometimes pointed to as an early example of a minicomputer, as it was small, transistorized and (relatively) inexpensive. However, its basic price of $ 100,000 (equivalent to $ 1,029,921 in 2023) and custom desk-like chassis places it within the "small system" or "midrange computer" category as opposed to the more modern use of the term minicomputer. Nevertheless, it retains a strong contender for

3410-481: 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

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3520-670: 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 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

3630-584: 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 the Literacy Project's call for bids for a computer to accompany the television programmes and literature, Acorn won the contract with

3740-664: 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

3850-592: 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 was a striking exception, bearing a modern design based on a monitor, keyboard, and tape and disk drives). Of

3960-646: The Processor Technology SOL-20 was designed, which consisted of one board which included all 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

4070-625: 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 the UK at the time. Acorn later employed the machine to simulate and develop the ARM architecture . While nine models were eventually produced with

4180-532: The Tube interface "the most innovative feature" of the computer, and concluded that "although some other British microcomputers offer more features for 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

4290-566: The workstation machines opened new markets for graphics-based systems that the terminal-oriented minis could not even address. Minis retained a force for those using existing software products or those who required high-performance multitasking, but the introduction of newer operating systems based on Unix began to become highly practical replacements for these roles as well. For computational science , clusters of commodity PCs largely replaced minicomputers. Mini vendors began to rapidly disappear through this period. Data General responded to

4400-622: 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 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

4510-460: 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

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4620-466: The ASR ;33. Another common difference was that most earlier small machines were not "general purpose", in that they were designed for a specific role like process control or accounting . On these machines, programming was generally carried out in their custom machine language , or even hard-coded into a plugboard , although some used a form of BASIC . DEC wrote, regarding their PDP-5, that it

4730-549: 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

4840-583: 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,

4950-452: 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

5060-433: 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, 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

5170-598: 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

5280-537: 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, 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

5390-528: 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

5500-516: 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

5610-537: 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

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5720-577: 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 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

5830-439: 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

5940-1292: The base software environment for the NonStop Servers, and has been extended to include support for Java and integration with popular development tools like Visual Studio and Eclipse . Later, Hewlett-Packard would split into HP and Hewlett-Packard Enterprise. The NonStop products and the DEC products would then be sold by HPE. A variety of companies emerged that built turnkey systems around minicomputers with specialized software and, in many cases, custom peripherals that addressed specialized problems such as computer-aided design , computer-aided manufacturing , process control , manufacturing resource planning , and so on. Many if not most minicomputers were sold through these original equipment manufacturers and value-added resellers . Several pioneering computer companies first built minicomputers, such as DEC , Data General , and Hewlett-Packard (HP) (who now refers to its HP3000 minicomputers as "servers" rather than "minicomputers"). And although today's PCs and servers are clearly microcomputers physically, architecturally their CPUs and operating systems have developed largely by integrating features from minicomputers. In

6050-458: The changing market by focusing entirely on the high-performance file server market, embracing a role within large LANs that appeared resilient. This did not last; Novell NetWare rapidly pushed such solutions into niche roles, and later versions of Microsoft Windows did the same to Novell. DEC decided to move into the large-computer space instead, introducing the VAX 9000 mainframe in 1989, but it

6160-501: 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

6270-558: 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

6380-529: 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

6490-498: 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

6600-482: 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

6710-472: The creation of an entire industry of minicomputer companies along Massachusetts Route 128 , including Data General , Wang Laboratories and Prime Computer . Other popular minis from the era were the HP 2100 , Honeywell 316 and TI-990 . Early minis had a variety of word sizes , with DEC's 12 and 18-bit systems being typical examples. The introduction and standardization of the 7-bit ASCII character set led to

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6820-489: The data collection crews. Raytheon Data Systems RDS 704 and later RDS 500 were predominantly the systems of choice for nearly all the geophysical exploration as well as oil companies. At the launch of the MITS Altair 8800 in 1975, Radio Electronics magazine referred to the system as a "minicomputer", although the term microcomputer soon became usual for personal computers based on single-chip microprocessors . At

6930-460: 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 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

7040-519: 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

7150-402: 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

7260-735: 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 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,

7370-485: The early 1980s, such as DEC's VAX , Wang VS , and Hewlett-Packard's HP 3000 have long been discontinued without a compatible upgrade path. OpenVMS was ported to HP Alpha and Intel IA-64 ( Itanium ) CPU architectures, and now runs on x86-64 processors. Tandem Computers , which specialized in reliable large-scale computing, was acquired by Compaq in 1997, and in 2001 the combined entity merged with Hewlett-Packard . The NonStop Kernel-based NonStop product line

7480-493: 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

7590-475: 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

7700-605: 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 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

7810-452: 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

7920-477: The foundation for all current versions of Microsoft Windows , borrowed design ideas liberally from VMS . Many of the first generation of PC programmers were educated on minicomputer systems. BBC Micro 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

8030-693: 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

8140-602: 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,

8250-535: 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

8360-513: 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

8470-649: The later 1970s. Most mini vendors introduced their own single-chip processors based on their own architecture and used these mostly in low-cost offerings while concentrating on their 32-bit systems. Examples include the Intersil 6100 single-chip PDP-8, DEC T-11 PDP-11, microNOVA and Fairchild 9440 Nova, and TMS9900 TI-990. By the early 1980s, the 16-bit market had all but disappeared as newer 32-bit microprocessors began to improve in performance. Those customers who required more performance than these offered had generally already moved to 32-bit systems by this time. But it

8580-652: The machines they had ordered. Efforts were made to market the machine in 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

8690-461: 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

8800-483: 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) 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

8910-498: 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

9020-423: The minicomputer class. Similar models using magnetic delay-line memory followed in the early 1960s. These machines, however, were essentially designed as small mainframes, using a custom chassis and often supporting only peripherals from the same company. In contrast, the machines that became known as minicomputers were often designed to fit into a standard chassis and deliberately designed to use common devices like

9130-533: The modern definition. Its introductory price of $ 18,500 (equivalent to $ 178,866 in 2023) places it in an entirely different market segment than earlier examples like the CDC 160. In contemporary terms, the PDP-8 was a runaway success, ultimately selling 50,000 examples. Follow-on versions using small scale integrated circuits further lowered the cost and size of the system. Its success led to widespread imitation, and

9240-496: The move to 16-bit systems, with the late-1969 Data General Nova being a notable entry in this space. By the early 1970s, most minis were 16-bit, including DEC's PDP-11 . For a time, "minicomputer" was almost synonymous with "16-bit", as the larger mainframe machines almost always used 32-bit or larger word sizes. As integrated circuit design improved, especially with the introduction of the 7400-series integrated circuits , minicomputers became smaller, easier to manufacture, and as

9350-547: The new RISC approach promised performance levels well beyond the fastest minis, and even high-end mainframes. All that really separated micros from the mini market was storage and memory capacity. Both of these began to be addressed through the later 1980s; 1 MB of RAM became typical by around 1987, desktop hard drives rapidly pushed past the 100 MB range by 1990, and the introduction of inexpensive and easily deployable local area network (LAN) systems provided solutions for those looking for multi-user systems. The introduction of

9460-584: 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

9570-544: 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

9680-598: 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

9790-449: The same time, minis began to move upward in size. Although several 24 and 32-bit minis had entered the market earlier, it was DEC's 1977 VAX , which they referred to as a superminicomputer , or supermini, that caused the mini market to move en-masse to 32-bit architectures. This provided ample headroom even as single-chip 16-bit microprocessors like the TMS 9900 and Zilog Z8000 appeared in

9900-569: 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

10010-471: The software context, the relatively simple OSs for early microcomputers were usually inspired by minicomputer OSs (such as CP/M 's similarity to Digital's single user OS/8 and RT-11 and multi-user RSTS time-sharing system). Also, the multiuser OSs of today are often either inspired by, or directly descended from, minicomputer OSs. UNIX was originally a minicomputer OS, while the Windows NT kernel ,

10120-474: 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,

10230-734: 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

10340-493: The term personal computer became generally used for microcomputers compatible with the IBM PC architecture ( IBM PC–compatible ). Minicomputer A minicomputer , or colloquially mini , is a type of smaller general-purpose computer developed in the mid-1960s and sold at a much lower price than mainframe and mid-size computers from IBM and its direct competitors . In a 1970 survey, The New York Times suggested

10450-468: 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, the IBM PC itself

10560-441: 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, 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

10670-543: The term "first minicomputer". Most computing histories point to the 1964 introduction of Digital Equipment Corporation 's (DEC) 12-bit PDP-8 as the first minicomputer. Some of this is no doubt due to DEC's widespread use of the term starting in the mid-1960s. Smaller systems, including those from DEC like the PDP-5 and LINC , had existed prior to this point, but it was the PDP-8 combination of small size, general purpose orientation and low price that puts it firmly within

10780-664: 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 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

10890-403: The time, microcomputers were 8-bit single-user, relatively simple machines running simple program-launcher operating systems like CP/M or MS-DOS , while minis were much more powerful systems that ran full multi-user, multitasking operating systems, such as VMS and Unix . The Tandem Computers NonStop product line shipped its first fully fault-tolerant cluster computer in 1976. Around

11000-417: The two-decade lifetime of the minicomputer class (1965–1985), almost 100 companies formed and only a half dozen remained. When single-chip CPU microprocessors appeared, beginning with the Intel 4004 in 1971, the term "minicomputer" came to mean a machine that lies in the middle range of the computing spectrum, in between the smallest mainframe computers and the microcomputers . The term "minicomputer"

11110-505: The ubiquitous Teletype Model 33 ASR. They usually took up one or a few 19-inch rack cabinets, compared with the large mainframes that could fill a room. In terms of relative computing power compared to contemporary mainframes, small systems that were similar to minicomputers had been available from the 1950s. In particular, there was an entire class of drum machines , like the UNIVAC 1101 and LGP-30 , that share some features of

11220-510: 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

11330-471: Was "the world’s first commercially produced minicomputer". It meets most definitions of "mini" in terms of power and size, but was designed and built to be used as an instrumentation system in labs, not as a general-purpose computer. Many similar examples of small special-purpose machines exist from the early 1960s, including the UK Ferranti Argus and Soviet UM-1NKh. The CDC 160 , circa 1960,

11440-490: Was a flop in the market and disappeared after almost no sales. The company then attempted to enter the workstation and server markets with the DEC Alpha , but was too late to save the company and they eventually sold their remains to Compaq in 1998. By the end of the decade all of the classic vendors were gone; Data General , Prime , Computervision , Honeywell , and Wang , failed, merged, or were bought out. Today, only

11550-474: 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 ,

11660-454: 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 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

11770-541: Was not long before this market also began to come under threat; the Motorola 68000 offered a significant percentage of the performance of a typical mini in a desktop platform. True 32-bit processors like the National Semiconductor NS32016 , Motorola 68020 and Intel 80386 soon followed. By the mid-1980s, high-end microcomputers offered CPU performance equal to low-end and mid-range minis, and

11880-417: Was re-ported from MIPS processors to Itanium-based processors branded as ' HP Integrity NonStop Servers'. As in the earlier migration from stack machines to MIPS microprocessors, all customer software was carried forward without source changes. Integrity NonStop continues to be HP's answer for the extreme scaling needs of its very largest customers. The NSK operating system, now termed NonStop OS , continues as

11990-467: 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

12100-551: 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

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