The Staffordshire University Computing Futures Museum Computers Page
The locations of the UK research teams developing computers at the end of the Second World War react on this clickable map.
Hover the mouse over your location of interest and left click to see details of developments at that location.
Ferranti Ltd, founded 1882, manufactured electrical equipment since the days of the founder, Sebastian de Ferranti (1864-1930), and the company was a major UK electrical engineering firm known primarily for defence electronics and power grid systems.
An initial appraisal of the potentials of stored-program computers was undertaken by the company in 1948 and this conveniently prepared the ground for the government-sponsored link with Manchester University. With the impetus of government money and the access to University research, Ferranti Ltd quickly became the largest British stored-program computer manufacturer. When they started selling computers in 1951 there was no real competition.
The first generation valve machines constructed by Ferranti at West Gorton, with collaboration of the Manchester and Cambridge research teams, included:
the Ferranti Mark I (1951), Mark I Star (1953),
and Pegasus 1 (1956).
The Ferranti Mercury (1957) remodelled the Manchester Mark I using transistors. Other machines were Pegasus 2 (1959), and Perseus (1959).
Ferranti manufactured silicon diodes from 1955, the F100-L 16-bit microprocessor in 1977, and uncommitted logic arrays used in the Sinclair ZX81, Sinclair ZX Spectrum, Acorn Electron and BBC Microcomputer in the 1980s. This microelectronics business was sold to Plessey in 1988.
In 1956 Ivan Edelson of Ferranti also originated the Cluff-Foster-Idelson 7-track paper tape code that eventually became ASCII.
In the late 1950s Ferranti Ltd embarked upon two substantial computer projects. The first was the giant ATLAS, a joint venture with Manchester University. This project was full of financial uncertainties: various estimates of the cost of the first production ATLAS ranged from £375,000 in February 1959, to £650,000 in November 1960, and to £930,000 in October 1962. At the same time Ferranti was developing another medium-to-large computer named ORION, which ran into some technical difficulties. These included problems with interconnecting the special circuits which had been designed to economise on the total number of transistors used.
The Atlas appeared in 1962, and a modification,
the Atlas 2 (or Titan), was developed in 1964 for University of Cambridge.
By January 1963 the value of computing equipment installed in the United Kingdom was estimated to be distributed amongst the manufacturers as follows: Ferranti 25%, ICT 25%, English Electric 13%, Elliott 12%, NCR 11%, Leo 7% and other manufacturers 7%.
By 1963 the first deliveries of ATLAS and ORION computers had begun, but sales were slow in coming. With the drain on resources occasioned by these two large computer developments and the growing competition from rival British companies in the mid-range market, some rationalisation of the industry had to take place. Ferranti's main computer interests were therefore sold to ICT in September 1963.
The Ferranti Digital Systems Division at Bracknell also developed a range of mainframe computers for naval applications. The ARGUS series was one of the outcomes of this and from 1963 onwards ARGUS was applied to non-military projects in great numbers. In the early 1960s other Ferranti defence computers such as POSEIDON, HERMES, the F1600 (discrete transistors) and FM1600 (integrated circuits) were built. Derivatives of the F1600 have been applied to several hundred civil as well as military projects world-wide.
Ferranti ceased trading in 1993, from financial and legal difficulties arising from its purchase of International Signal and Control, a USA defence contractor.
The British Tabulating Machine Company (BTM) was a firm which manufactured and sold Hollerith unit record equipment and other data-processing equipment. During World War II, BTM constructed a number of Turing Bombe machines used at Bletchley Park to break the German Enigma machine ciphers.
The company was formed in 1902 as The Tabulator Limited, after Robert Porter obtained the rights to sell Herman Hollerith's patented machines from the US Tabulating Machine Company (TMC, later to become (IBM). BTM contacted TMC with a view to licensing the technology and introducing it to the UK. Hollerith asked for a payment of £20,000, later lowering it to £10,000 for the licence to sell the tabulating machines in the UK and Europe. Porter attempted to raise the required finance from bankers, friends and even families, but could only manage £2,000. Having failed, they returned to TMC and asked whether this sum plus a 25% royalty on all the revenue of BTM would be acceptable. TMC agreed, with the proviso that BTM could only hire out the technology purchased from TMC, and the deal was struck. BTM soon realised that they had come off extremely poorly in the bargain, and for a number of years made very little profit. Most of their money was taken up by buying machines from TMC at dictated prices, and on top of this they had to pay the 25% royalty. The market for the new machines did not take off in Britain as it had in the USA, and it was not long before BTM were defaulting on their royalty payments to TMC.
By 1909 the Tabulator Limited had been renamed the British Tabulating Machine Company Limited. In 1920, the company moved from London to Letchworth, Hertfordshire; it was also at this point that it started manufacturing its own machines, rather than simply reselling Hollerith equipment.
TMC became part of the Computing-Tabulating-Recording Company (C-T-R) in 1911, later renamed as International Business Machines (IBM) in 1924. The new management of IBM discovered that BTM had defaulted payments, and saw them as a company who had failed to capitalise on the technology market opportunities, deserving of contempt, while BTM saw themselves as being bled dry by IBM. This difference of opinion led to IBM holding back spare parts, a ploy which was frequently used by IBM for many years. A request from BTM for the dropping of the 25% royalty was declined by IBM, and the relationship got worse when Thomas J. Watson was appointed — during the 1920s and 1930s he turned IBM into a fantastic success which BTM could never hope to match. This unfortunate hiring and royalty decision was to plague BTM right through their development until the agreement was terminated in 1948. It was ultimately the reason for the extremely hostile relationship which grew between IBM (having taken over the interests of TMC) and ICL (having taken over BTM) until the 1970s.
During World War II BTM were helped enormously by the British Government, who employed them to build the Turing Bombe machines at Bletchley Park to crack the Enigma codes. This left BTM with greatly increased assets after the war, assets which the UK Government had paid for.
The 1953 BTM HEC2 computer
In 1959 BTM merged with former rival company Powers-Samas to become International Computers and Tabulators Limited (ICT). ICT later became part of International Computers Limited (ICL).
Powers-Samas was a British company which sold unit record equipment. The company was in competition with the British Tabulating Machine Company (BTM), with which it eventually merged in 1959 to form International Computers and Tabulators (ICT). Powers-Samas was also known as "Acc and Tab" (Accounting and Tabulating).
The Powers Accounting Machine Company was formed by James Powers in New York in 1911. Powers had worked as a technical expert for the American Bureau of Census, largely working on the maintenance of Hollerith’s tabulating machinery. Whilst working for the Bureau, Powers made several improvements on Hollerith’s original designs, the most important being the incorporation of an automatic printing mechanism (“tabulator”). The Powers machines also made use of a mechanical hole-sensing mechanism, much more reliable that the Hollerith mercury electrical system which was affected by conductive impurities in the cards. However, many features of the Powers machines were very close to the Hollerith machines, and this resulted in a lawsuit being brought by a German company, acting for C-T-R, on copyright grounds. Although the German company won, they were obliged to grant Powers Germany a licence to use Hollerith’s patents on a royalty basis. Powers continued to develop the machines, adding slide punching machines, removable and easily programmable tabulator boxes, etc. and all this led to increased competition within the industry.
A company formed by the Prudential Building Society, Accounting and Tabulating Company of Great Britain (Acc & Tab) in 1914 added to the competition in Britain, and formed a relationship with Powers in the USA.
1930 Powers-Samas Accounting Machine
This relationship eventually led to Acc & Tab becoming known as Powers (UK). The parent Powers company was taken over in the formation of Remington Rand, becoming known as the “Tabulating Machine Division” of Remington, and this company later became Univac. The relationship between Remington and Powers (UK) then became difficult. After a merger with the Samas company in 1929, the new title Powers-Samas was adopted. The company was then bought out by Vickers and continued to compete with BTM until both became part of ICT.
Metropolitan Vickers (Metrovick) was a British heavy electrical engineering company, formerly known as British Westinghouse, with a very large factory at Trafford Park, Manchester. The name derives from the Metropolitan Carriage, Wagon and Finance Company of Birmingham, and Vickers Limited of Barrow-in-Furness, who in 1919 wrested the company from USA control and renamed it as Metropolitan Vickers. Metrovick was thus founded in the same year as English Electric, and was a significant rival to EE, with a very similar range of products.
In 1928 Metrovick merged with British Thomson-Houston (BTH), and in 1929 this joint company was purchased by Associated Electrical Industries (AEI). The company manufactured Avro Manchester and Lancaster bombers during World War II, and after the war many diesel locomotives.
GEC purchased AEI in 1967.
Tom Kilburn's group at Manchester University built the MU3, a small transistor research computer to gain some experience with the new devices. Two versions of the computer were completed, in November 1953 and April 1955 respectively, both with drum stores.In 1956 Metrovick adapted the prototype's design to form the basis of their MV950 computer, using junction transistors.
International Computers and Tabulators (ICT) was formed in 1959 by a merger of the British Tabulating Machine Company (BTM) and Powers-Samas.
Thorn EMI was a major British company involved in consumer electronics, music, defence and retail. It was created in October 1977 when Thorn Electrical Industries merged with EMI.
The EMIDEC 1100 computer was produced by the Computing Services Division of EMI Laboratories. Because transistors were relatively slow at that time, core memory (a matrix of laced ferrite cores) was used to achieve a processing power comparable with a valve/tube computer. These logic units consisted of a single ferrite ring (toroid) with up to fifteen connections. The main storage capacity was 1,024 words, each of 36 bits - just over 4k bytes.The backup storage was provided by magnetic drums, each of 4,096 registers - about 20k, and one-inch wide magnetic tape drives. Peripherals included punched tape readers, punched card readers, and line printers. This machine was sold as the ICT 1101 when the EMI computer interests merged with ICT in 1962.
The 1955 BTM Hollerith Electronic Computer Mark 4 (HEC4) was part of the range of APEC machines developed by Andrew Booth at Birkbeck College with the support of BTM. The computer used thermionic valve technology and its main memory was drum storage. Input was from 80 column punched cards and output was to 80 column cards and a printer. This machine was sold as the ICT 1201 when BTM became part of ICT in 1962.
The ICT 1301, and its smaller cousin the ICT 1300, used germanium transistors and core memory. Backing store was magnetic drum, and optionally one inch, half inch or quarter inch wide magnetic tape. Input was from 80 column punched cards and optionally 160 column punched cards and punched paper tape. Output was to 80 column punched cards, printer and optionally to punched paper tape. The first customer delivery was in 1962, a 1301 sold to the University of London. One of their main attractions was that they performed British currency calculations (pounds, shillings and pence) in hardware. They also had the advantage of programmers not having to learn binary or octal arithmetic as the instruction set was pure decimal and the arithmetic unit had no binary mode, only decimal or pounds, shillings and pence. Its clock ran at 1 MHz.
The ICT 1302 used similar technology to the 1300/1301 but was a multiprogramming system capable of running three programs in addition to the Executive. It also used the 'Standard Interface' for the connection of peripherals allowing much more flexibility in peripheral configuration. The 'Standard Interface' was originally prototyped on the 1301 and went on to be used on the 1900 series.
The ICT 1500 series was a design bought in from the RCA Corporation, who called it the RCA 301. RCA also sold the design to Siemens in Germany and Compagnie des Machines Bull in France who called it the Gamma 30. It used a 6 bit byte and had core stores of 10,000, 20,000 or 40,000 bytes.
In 1963 the business computer divisions of Ferranti were added.
The ICT 1900 series was devised after the acquisition of Ferranti's assets which brought in the new Ferranti-Packard 6000 machine from Ferranti's Canadian subsidiary, which was considerably more advanced than the existing 130x line. It was decided to adapt this machine to use the 'Standard Interface', and it was put on the market as the ICT 1904, the first in a range of upward-compatible computer systems.
In 1968 ICT merged with English Electric Computers, itself formed from the prior mergers of English Electric Leo Marconi (EELM) and Elliott Automation. The resulting company became International Computers Limited (ICL). The financial arrangements were the original assets of English Electric Computers Ltd (18%) and ICT (53%), together with money from the memory manufacturer Plessey (18%), and an unprecedented Government shareholding (11%). At the time of the merger English Electric Computers was in the process of making a line of large IBM System/360-compatible mainframes based on the RCA Spectra 70, which was sold as the ICL System-4.
Combined sales of ICT machines 1951 - 1968 and ICL machines 1968 - 1971, including early large and medium scientific machines, early small aand medium general application machines, business machines and scientific machines (1951 - 1959 BTM and Powers Samas; 1962 Thorn EMI added; 1963 Ferranti added; 1968 ICL merger)
Both the ICT 1900 series and EE System-4 series were eventually replaced by the ICL 2900 Series which was introduced in 1974, using hardware emulators in order to run software from both systems.
Clive Sinclair founded his first company Sinclair Radionics Ltd in Cambridge on 25.07.1961, manufacturing hifi products, radios, calculators and scientific instruments.
When the National Enterprise Board became involved in financing the company in 1976, Sinclair encouraged Chris Curry, who had been working for Sinclair Radionics since 1966, to leave and to get Sinclair Instrument Ltd up and running. The company's first product was a watch-like Wrist Calculator.
The company went on to produce a range of calculators, including the 1975 Sinclair Scientific Programmable calculator that worked in Reverse Polish Notation.
The company was renamed Science of Cambridge Ltd in July 1977. In June 1978 a microcomputer based on the National Semiconductor SC/MP microprocessor and some parts of a Sinclair calculator was launched as the MK14 microcomputer kit.
In February 1980 a new microcomputer based on the Zilog Z80 microprocessor was launched as the ZX80, costing £79.95 in kit form and £99.95 ready-built. In November 1980 the company was renamed Sinclair Computers Ltd.
In March 1981 Sinclair Computers Ltd was renamed Sinclair Research Ltd and the Sinclair ZX81 was launched, costing at £49.95 in kit form and £69.95 ready-built.
In January 1983 the ZX Spectrum personal computer was launched.
The Sinclair QL costing £399 was announced on 12.01.1984, shortly before the Apple Macintosh went on sale, but fully-working versions of the QL were not available until late summer 1984.
The ZX Spectrum+, a repackaged ZX Spectrum with a QL-like keyboard, was launched in October 1984 and appeared on W H Smith's shelves the day after release. Retailers stocked the machine in large numbers in expectation of good Christmas sales. However the machine did not sell in the numbers expected.
Sir Clive had long held an interest in electric vehicles and during the early 1980s worked on the design of a single-seater "personal vehicle". A new company Sinclair Vehicles Ltd was formed in March 1983 and its Sinclair C5 electric vehicle was launched on 10.01.1985, costing £399. It was a commercial disaster.
In early 1985 Robert Maxwell announced a takeover of Sinclair Research, through Hollis Brothers, a subsidiary of his Pergamon Press. However the deal was aborted in August 1985. Sinclair Research's future remained uncertain until 07.04.1986, when the entire computer product range and the "Sinclair" brand name (but not the company itself) was sold to Amstrad.
Sinclair Research Ltd still exists today as a one man company, Sir Clive himself, continuing to market his newest inventions.
GEC Computers
The data processing computing assets of Elliott Automation were transferred to ICT in 1961, and non-computing products were passed to English Electric as part of a reorganisation of the parent company forced by the British Government.
Elliott Automation retained the industrial process control Elliott 900 series of computers, and set about designing a new range of computer systems. The rules of the reorganisation prevented Elliott Automation from working on data processing computing products for some years after the split (and similarly, disallowed ICT from working on industrial process control computing products). English Electric was merged with GEC in 1968.
Three new computer ranges were identified, known internally as Alpha, Beta, and Gamma.
Alpha became the GEC 2050 8-bit minicomputer,
and Beta became the GEC 4080 16-bit minicomputer.
Gamma was never developed, so a few of its enhanced features were consequently implemented in the GEC 4080.
GEC 4080 Front Panel
The main company product was the GEC 4000 series minicomputers, which were used by many other GEC and Marconi companies as the basis for real-time control systems in industrial and military applications, and development of many new computers in the series continued through most of the life of the company. Other products manufactured in the earlier years were computer power supplies, and high-resolution military computer displays, as well as the Elliott 900 series for existing 900 series customers. GEC Computers also found that some of the software applications it developed for its own use could be sold to other companies, such as its salary payment services, its multi-layer printed circuit board design software, and its project management software.
In the mid 1970s GEC Computers was working on OS4000, a more advanced operating system for the GEC 4000 series. This opened up the GEC 4000 series computers to more customers, including many in the academic and research communities. A number of collaborative projects ran, some of which resulted in applications which GEC Computers developed further and sold, such as the X.25 packet switching systems, which resulted from a research collaboration with NERC. In the late 1970s the UK General Post Office developed the Prestel teletext system on the GEC 4000 series. This resulted in sales of similar systems all over the world.
By 1980, OS4000 was becoming quite popular in the UK academic and research organisations as a multi-user system, with installations at Rutherford-Appleton Laboratory, Daresbury Laboratory, Harwell Laboratory, NERC, Met Office, CERN, in many university Physics and/or Engineering departments, and as the main central computer services at University College London (Euclid) and Keele University.
Throughout the 1980s, GEC Computers expanded from its Borehamwood offices into 3 large purpose-built factory units in Woodside Estate, Dunstable. The company closed these as the business contracted in the 1990s.
GEC Computers collaboration with Sun Microsystems led to the Sun-2 product range in the early 1980s, which GEC Computers sold under the name of GEC Series 42. These manufactures ceased when GEC was absorbed by Alstom.
Alan Sugar founded the electronic company Alan Michael Sugar TRADing (AMSTRAD) in 1968. Between 1984 and 1990 the company produced several Amstrad CPC (short for Colour Personal Computer) models, including the
CPC464, CPC664 and CPC6128, competing with the Commodore 64, Sinclair ZX Spectrum and Acorn BBC Microcomputer.
In 1986 Amstrad bought the surplus stock and manufacturing rights of Sinclair Research computers, together with the Sinclair brand name, although not the company itself. Two new versions of the Spectrum, the ZX Spectrum +2 and the ZX Spectrum +3 were then produced. Sugar sold Amstrad to BSkyB in 2007.
Having chaired the popular TV series The Apprentice, on 05.06.2009 Alan Sugar became Baron Sugar and the Government's "Enterprise Champion", a political neutral appointment to help business and enterpreneurs.
Lord Sugar is the owner of Viglen Ltd, formed in 1975 and acquired by Amstrad in 1994, an IT services provider to the schools, colleges
and public sectors. The current computers produced are the
Genie range using Intel Core 2 Duo technology.
Research Machines (RM) was founded in 1973 in Oxford by Mike Fischer and Mike O'Regan, graduates of Oxford and Cambridge Universities respectively. Initially it traded under the name Sintel which was a mail-order supplier of electronic components, mainly dealing with the hobbyist market. Fischer and O'Regan chose the educational and scientific market because they judged that their business would not be able to grow fast enough to be successful in the general computer market dominated by existing big players. With the arrival of microcomputer chips in the mid-1970s, the company expanded into the design and manufacturing of microcomputers. The company shipped its first computer in 1977 to a customer in a Local Education Authority and has been involved with educational computing ever since.
The company's early presence in educational computing came at a time when the UK government was encouraging the use of computers in schools through the Microelectronics Education Programme. Throughout the 1980s RM and Cambridge-based rival Acorn Computers provided computers to the majority of schools in the UK. The company was offered, but refused, the chance to design and manufacture the BBC microcomputer (subsequently designed and made by Acorn), on the grounds that to do so would bankrupt the company.
RM was the first significant supplier of LAN computer networks in the UK and, working with Zilog, developed Z-Net, a low-cost network technology that was widely used in UK schools particularly for networks of the RM Nimbus model. Z-Net was subsequently replaced by what later become the industry standard, Ethernet.
RM's early microcomputers were the RM 280Z,
RM 380Z and Link 480Z, all based on the Zilog Z80A microprocessor. The Group switched to the Intel 80186 microprocessor with the launch of the Nimbus PC-186 in 1984. While not 100% IBM PC compatible, the Nimbus PC-186 ran the Microsoft MS-DOS operating system and Windows 1. Thus the company was one of the first microcomputer firms to adopt Windows. Since 1986, with the introduction of the Nimbus AX and VX models, all RM computers have been fully IBM compatible.
The company floated on the London Stock Exchange in November 1994 under the name RM plc.
RM cooperated with Microsoft in the production of early networking software. Various generations of RM’s networking products, all of which have been built on standard Microsoft networking software, are currently in use, the most recent version being Community Connect 4, released in June 2008.
In October 2007 RM launched the RM Asus Minibook, a re-branded Asus computer, in the UK.
Acorn Computers was a British computer company established in Cambridge in 1978. After losing control of his computer operations to the National Enterprise Board, Clive Sinclair had encouraged Chris Curry to leave Sinclair Radionics and to set up Science of Cambridge. Hermann Hauser and Curry set up the Cambridge Processor Unit Ltd (CPU) on 05.12.1978, which developed a SC/MP microprocessor-based controller for fruit machines.
Acorn Computers was another trading name used by CPU to separate this product line from the 6502 microcomputer-based Acorn System 1 which was launched in January 1979. The name "Acorn" was chosen so that it would precede "Apple" in the telephone directory. The company produced a number of computers which were especially popular in the UK. These included the Acorn Electron, the
BBC Micro and the Acorn Archimedes. Acorn's BBC Micro computer dominated the UK educational computer market during the 1980s and early 1990s, drawing many comparisons with Apple in the U.S.
Acorn's watershed year was in 1984, when the home computer market collapsed. It was the year in which Apple nearly went bankrupt. After one of Acorn's creditors had issued a winding-up petition, Curry and Hauser signed an agreement with Olivetti on 20.02.1985 whereby Olivetti took a 49.3% holding. Later market fluctuations then enabled Olivetti to obtain a controlling interest of 79% of Acorn's shares.
Though the company was broken up into several independent operations in 1998, its legacy includes the development of RISC personal computers.
Companies are listed in order of date of foundation.
Hollerith punched card machinery had been developed from 1881, when it was first used for the USA Census.
1890 Hollerith census tabulator
1911 Incorporation of the Computing Tabulating Recording Corporation (CTR, a forerunner of IBM): key personnel were Hermann Hollerith and Thomas J. Watson.
Significant achievements of IBM:
1953 IBM 701
Honeywell was founded in 1906.
Honeywell originally entered the computer business in 1955 via a joint venture with Raytheon called Datamatic Corporation, but soon bought out Raytheon's share and the business became a Honeywell division. The Honeywell 800 was produced, later updated to the Honeywell 1800.
In 1963, Honeywell introduced a small business computer, the Honeywell 200 (above), to compete with IBM's 1401. That began a product line that continued until the early 1970s.
Honeywell also purchased minicomputer pioneer Computer Control Company in 1966, renaming it as Honeywell's Computer Control Division. Through most of the 1960s, Honeywell was one of the "Snow White and the Seven Dwarfs" of computing. IBM was "Snow White," while the "dwarfs" were the seven significantly smaller USA computer companies. Later, when their number had been reduced to five, they were known as "The Bunch", after their initials: Burroughs, UNIVAC, NCR, Control Data Corporation, and Honeywell.
In 1970, Honeywell bought General Electric's computer division.
Groupe Bull acquired Honeywell Information Systems in the late 1980s.
Groupe Bull was nationalised in 1982 and was then merged with most of the rest of the French computer industry.
In 1991 the Honeywell Computer Division was sold to Groupe Bull.
In 1994 Groupe Bull was re-privatised.
After a merger with AlliedSignal in 1999 Honeywell changed its name to Honeywell International Inc.
Tandy Corporation began in 1919 as a leather goods company based in Fort Worth, Texas, which is best known for purchasing and giving its name to the Fort Worth, Texas-based RadioShack Corporation. Tandy was founded in 1919 as a leather supply store, and acquired RadioShack in 1963. The Tandy name was dropped in May 2000, when RadioShack Corporation was made the official name, apart from in the United Kingdom where the RadioShack name was already in use.
Tandy was one of the companies (along with Commodore International and Apple) that started the personal computer revolution, with their
TRS-80 (1977) and TRS-80 Color Computer ("CoCo") (1980) line of home computers. Later Tandy adopted the IBM PC architecture. Tandy's IBM PC compatibles, the Tandy 1000 and Tandy 2000, were cheaper than the IBM PC and featured built-in sound and graphics.
In the early 1990s Tandy Corporation sold its computer manufacturing business to AST Computers and all the Tandy computer lines were terminated. When that occurred, Radio Shack stores began selling computers made by other manufacturers, such as Compaq.
From the 1970s Tandy operated a chain of RadioShack-style stores in Britain and Australia. In 1999 the UK stores were sold to Carphone Warehouse, and in 2001 the Australian stores were sold to a subsidiary of Woolworths Limited.
RCA Corporation, founded as Radio Corporation of America, was an electronics company in existence from 1919 to 1986. It was the radio-manufacturing remnant of the Marconi Company of Guglielmo Marconi in the USA, the sole broadcasting rights having been ceded to the NBC by the US Government. RCA was instrumental in passing transistor and integrated circuit expertise and computer designs to English Electric, Kidsgrove in the UK. Compagnie des Machines Bull (CMB) was a close associate of RCA in the early 1960s, before CMB was acquired by General Electric (GE).
RCA abandoned computers in 1971: its computer business was taken over by Univac, and the rest of the company was bought by GE and the French group Thomson in the 1980s.
RCA 501
The RCA 501 (1958) was the first computer designed as a high-end general purpose system. It was sold in the UK by English Electric as the KDP10, and the Kidsgrove-designed KDF9 used the same technology.
RCA 501 magnetic tapes
RCA 501 printed circuit boards
RCA Spectra 70
The 1965 RCA Spectra series computers were the first computers commercially available that made use of integrated circuits designed in the RCA labs. Their User Mode was very similar to that of the IBM S/360. There was also a Supervisor Mode interrupt mechanism. The RCA Spectra 70/45 was sold in the UK by English Electric as the System 4-50, and the Kidsgrove-designed System 4-70 used the same technology. The Spectra series was also manufactured by Siemens, as the Siemens 4004. Siemens developed compatible processors and the BS/1000 operating system.
Hewlett-Packard Company (HP) was founded by William Hewlett and David Packard, who graduated in electrical engineering from Stanford University in 1935. They were mentored by their former university teacher Frederick Ternan, and the company was set up in Packard's garage in 1939, incorporated in 1947, and introduced to the stock market in 1957.
From the 1940s until well into the 1990s the company concentrated on making electronic test equipment. HP is recognized as the symbolic founder of Silicon Valley, although it did not actively investigate semiconductor devices until 1957. HP spun off a small company, Dynac, to specialize in digital equipment, and experimented with using Digital Equipment Corporation minicomputers with its instruments. But after deciding that it would be easier to build another small design team than deal with DEC, HP entered the computer market in 1966 with the
HP 2100 / HP 1000 series of minicomputers. These had a simple accumulator-based design, with registers arranged somewhat similarly to the Intel x86 architecture still used today. The series was produced for 20 years, in spite of several attempts to replace it, and was a forerunner of the HP 9800 and HP 250 series of desktop and business computers.
It is claimed that the world's first marketed, mass-produced personal computer was the Hewlett-Packard 9100A, introduced in 1968, although HP called it a desktop calculator.
Steve Wozniak, co-founder of Apple in 1976, originally designed the Apple I computer while working at HP and offered it to them under their right of first refusal to his work, but they did not take it up as the company wanted to stay in scientific, business, and industrial markets.
During the 1970s the HP 3000 was an advanced stack-based design for a business computing server, later redesigned with RISC technology.
The 98x5 series of technical desktop computers started in 1975 with the 9815, and the cheaper 80 series, again of technical computers, started in 1979 with the 85. These machines used a version of the BASIC programming language which was available immediately after they were switched on, and used a proprietary magnetic tape for storage. HP computers were similar in capabilities to the much later IBM Personal Computer, although the limitations of available technology forced prices to be high.
In 1984, HP introduced both inkjet and laser printers for the desktop. Along with its scanner product line, these have later been developed into successful multifunction products, the most significant being single-unit printer/scanner/copier/fax machines.
In the 1990s, HP expanded their computer product line, which initially had been targeted at university, research, and business users, to reach home consumers.
HP merged with Compaq in 2002.
John Vincent Atanasoff and Clifford Edward Berry, Iowa State University.
The 1942 Atanasoff-Berry Computer (ABC) can be considered joint first electronic digital computing device in the world, the other contender being the secret Colossus machine at Bletchley Park, UK. The 1941 German Zuse Z3 computer, although predating the ABC, was electromechanical rather than electronic. The ABC was not programmable, being designed only to solve systems of linear equations. The ABC implementation was not widely known, but in 1973 a U.S. District Court invalidated the ENIAC patent, concluding that Eckert and Mauchly had used computing ideas first implemented in the ABC. The details of the joint contender, Colossus, conceived 1942, remained secret until the 1970s. The ABC pioneered binary arithmetic, electronic switching, memory and parallel processing, but it was not Turing Complete because it did not have a stored program.
Howard Aiken, Harvard University
1944 electromechanical Automatic Sequence Controlled Calculator (ASCC), later named the Harvard Mark I, with help from Grace Hopper and funding from IBM. This computer was program-controlled by 24-channel punched paper tape, but had no conditional branch instruction.
1947 Mark II
Mark III (some electronic components, magnetic drum)
Mark IV (all-electronic, magnetic drum, magnetic core memory).
EDVAC
John von Neumann, Moore School of Electrical Engineering, University of Pennsylvania.
The Electronic Discrete Variable Automatic Computer (EDVAC, 1944) was installed at the U.S. Army's Ballistics Research Laboratory at the Aberdeen Proving Ground by the Moore School of Electrical Engineering, University of Pennsylvania.
John von Neumann was the sole author of the 1945 Electronic Discrete Variable Automatic Computer (EDVAC) Report.
ENIAC
Presper Eckert and John Mauchly, Moore School of Electrical Engineering, University of Pennsylvania.
The Electronic Numerical Integrator And Calculator (ENIAC, 1946) was the first Turing Complete stored-program electronic computer in the world. The Universal Turing Machine can perform any program that any other programmable computer is capable of. However, "Turing Completeness" is often ascribed to physical computers that would be "Universal" if they had unlimited (infinite) memory. Charles Babbage's Analytical Engine would have been the first Turing Complete machine if it had been completed at the time it was designed. However, ENIAC was not the first working electronic computer in the world, as was stated at the time. The Official Secrets Act had prevented the revelation that the 1944 Colossus machine at Bletchley Park was the first electronic computer, and ENIAC was program-controlled by patch cables and switches, just like Colossus. In 1948 a primitive read-only stored program mechanism was added to ENIAC using a ROM. Eckert and Mauchly later had their own company, and also worked with Remington Rand.
UNIVAC
Presper Eckert and John Mauchly, UNIVAC
The UNIVersal Automatic Computer (UNIVAC I, 1951) was the first US-produced commercial computer; commercial computers were also being manufactured in the UK by LEO. The UNIVAC I had magnetic tapes for backing memory.
The UNIVAC 1107 had thin film core memory.
The transistor-based UNIVAC 1108 (1964) supported up to three CPUs and had more than 1MB of integrated circuit memory.
Commodore International, founded 1954, was a US electronics company based in West Chester, Pennsylvania that played a role in the development of the home and personal computer industry in the 1980s. The company is also known under the name Commodore Business Machines (CBM).
The Commodore Personal Electronic Transactor (PET) was a home/personal computer produced by Commodore from 1977. It was a top seller in the Canadian, USA, and UK educational markets.
Commodore also developed and marketed the world's best-selling desktop computer, the Commodore 64 (1982). The company declared bankruptcy in 1994.
Seiko Epson Corporation, or Epson, is a Japanese technology company and one of the world's largest manufacturers of computer printers, information and imaging related equipment. Seiko itself specialises in watches.
In 1961 Shinshu Seiki Co. Ltdwas established as a subsidiary of Suwa Seikosha to supply precision parts for Seiko watches. When the Seiko Group was selected to be the official time keeper for the 1964 Summer Olympics in Tokyo, a printing timer was required to time events, and Shinshu Seiki started developing an electronic printer. In September 1968, Shinshu Seiki launched the world's first miniprinter,
the EP-101 (EP stands for Electronic Printer,) which was soon incorporated into many calculators. In June 1975, the name EPSON (SON of Electronic Printer) was coined for the next generation of the EP-101 . In April of the same year Epson America Inc. was established to sell printers for Shinshu Seiki Co.
In June 1978 the TX-80, an 80-column dot-matrix printer was released to the market, and was mainly used as a system printer for the Commodore PET computer. Dot-matrix printers were very practical for the printing of Japanese and Chinese characters. After two years of further development, an improved model,
the MX-80, was launched in October 1980. This was soon the best selling printer in the USA.
In November 1981 Epson introduced the world's first portable laptop (1.7 Kg),
the Epson HC-20 which featured a full-size keyboard, two Hitachi 6301 0.614 MHz CPUs, a 120 x 32 dot-matrix LCD screen (20 x 4 characters), dot-matrix printer, a microcassette storage device, RS232 Serial Port, 16KB RAM (32KB max), and built-in rechargeable batteries. Microsoft BASIC was installed in the ROM unit.
In July 1982 Shinshu Seiki was renamed as the Epson Corporation. In November 1985 Suwa Seikosha Co., Ltd. and Epson Corporation merged to form Seiko Epson Corporation.
The company developed Micro Piezo inkjet technology,
which used a piezoelectric crystal in each nozzle, rather than a heater to heat the ink at the print head while spraying the ink onto the page, and released the Epson MJ-500 inkjet printer (Epson Stylus 800 cartridge) in March 1993. In 1994 Epson released the first high resolution color inkjet printer (720 x 720 dpi was then considered as a high resolution),
the Epson Stylus Color printer, utilizing the Micro Piezo head technology. There have been many newer models of the Stylus series, employing Epson’s special DURABrite ink.
In June 2003 the company became public following their listing on the Tokyo Stock Exchange.
Digital Equipment Corporation (DEC) introduced in 1964 the first mass-produced minicomputer, the PDP-8. It was developed at the DEC plant in Reading, UK. The machine had a 12-bit word and programs were written using a one-to-one interpreter. Program and data areas of the memory were not isolated, so a common programming trick was to overwrite instructions while a program was running.
The DEC PDP-8
The DEC PDP-8 console with its bit switches and lamps. Note the 12-bit word (4 groups of 3 bits). Numbers were written in octal (base 8).
The DEC PDP-8 interior
Subsequent machines developed were the 16-bit PDP-11 and 32-bit VAX ranges. Virtual Address eXtension (VAX) was an instruction set architecture (ISA) developed in the mid-1970s. The VAX name was also used by DEC for a family of computer systems based on this processor architecture. The first VAX model sold was the VAX-11/780, which was introduced on 25.10.1977. Many different models with different prices, performance levels, and capacities were subsequently created, with VAX superminis being very popular in the early 1980s.
1977 VAX-11/780
The VAX architecture was eventually superseded by RISC technology. In 1989 DEC introduced a range of DECstation and DECsystem workstations and servers that ran Ultrix. In 1992 DEC introduced their own RISC instruction set architecture, the Alpha AXP (later renamed Alpha), and their own Alpha-based microprocessor, the DECchip 21064, a high performance 64-bit design capable of running OpenVMS. In August 2000 Compaq announced that the remaining VAX models would be discontinued, and by 2005 all manufacturing of VAX computers had ceased, but old systems remained in widespread use.
Cray Inc. is a supercomputer manufacturer based in Seattle, Washington. The company's predecessor, Cray Research Inc. (CRI), was founded in 1972 by computer designer Seymour Cray.
Seymour Cray began working in the computing field in 1950 when he joined Engineering Research Associates (ERA) in Saint Paul, Minnesota, later part of UNIVAC. He left ERA in 1960 and joined Control Data Corporation (CDC). Cray had a string of successes at CDC, including the CDC 6600 and CDC 7600. However the company ran into financial difficulties in the late 1960s. When he was told in 1972 that further developments would have to be put on hold, Cray left to form his own company, Cray Research Inc., with research and development facilities in Chippewa Falls and the business headquarters in Minneapolis.
The 1976 Cray-1 was a major success when it was released. Cray soon left the CEO position of Cray Research Inc. to become an independent contractor, and in 1979 started a new laboratory for the
Cray-2 in Boulder, Colorado, Cray Laboratories. This was closed in 1982, and in 1989 Cray headed Cray Computer Corporation (CCC) in Colorado Springs, working on the Cray-3 project. However, there was little support for such a supercomputer at the end of the Cold War, and company filed for bankruptcy in 1995.
Cray Research merged with Silicon Graphics (SGI) in February 1996. SGI immediately sold off the Superservers business to Sun, and used Cray technologies in their attempt to move from the graphics workstation market into supercomputing. SGI later set up a separate Cray Research Business Unit and then sold it to Tera Computer Company in 2000, which was renamed Cray Inc.. This company has gone on to produce a number of supercomputers.
Microsoft Corporation is a multinational computer technology corporation that develops, manufactures, licenses, and supports a wide range of software products for computing devices. Headquartered in Redmond, Washington, USA, its most profitable products are the Microsoft Windows operating system and the Microsoft Office suite of productivity software.
Microsoft was founded on 04.04.1975 by Bill Gates and Paul Allen in Albuquerque, to develop and sell BASIC interpreters for the
Altair 8800.
Starting in 1980 Microsoft formed an important partnership with IBM that allowed them to bundle Microsoft's operating system with computers that they sold, paying Microsoft a royalty for every sale.
Disk Operating System (DOS) was the operating system that brought the company its real success. On 12.08.1981 IBM awarded a contract to Microsoft to provide a version of the CP/M operating system, which was to be used in the IBM Personal Computer (PC). For this work Microsoft purchased 86-DOS from Tim Paterson, which IBM renamed to PC-DOS.
In 1985 IBM requested that Microsoft write a new operating system for their computers called OS/2; Microsoft wrote the operating system, but also continued to sell their own alternative, which proved to be in direct competition with OS/2.
On 20.11.1985 Microsoft released its first retail version of
Microsoft Windows, originally a graphical extension for its MS-DOS operating system to provide some of the features of the Apple GUI.
In 1989 Microsoft introduced its flagship office suite,
Microsoft Office. The software bundled several office productivity applications, such as Microsoft Word and Microsoft Excel. Microsoft Word became notable for its concept of "What You See Is What You Get" (WYSIWYG).
On 22.05.1990 Microsoft launched Windows 3.0. The new version of Microsoft's operating system boasted such new features as streamlined user interface graphics and improved protected mode capability for the Intel 386 processor. Windows began to generate more revenue for Microsoft than OS/2, and the company then decided to move more resources from OS/2 to Windows. When Microsoft launched several versions of Microsoft Windows in the 1990s, they captured over 90% software market share of the world's personal computers. In the ensuing years, the popularity of OS/2 declined, and Windows quickly became the favoured PC platform.
In 1993 Microsoft released Windows NT 3.1, a business operating system with the Windows 3.1 user interface but an entirely different kernel.
In 1995 Microsoft released Windows 95, a new version of the company's flagship operating system which featured a completely new user interface, including a novel Start Button. The company also released its
web browser Internet Explorer in August 1995.
In 1997 Internet Explorer 4.0 was released for both Mac OS and Windows, marking the beginning of the takeover of the browser market from rival Netscape.
In 1998 Microsoft released Windows 98, an update to Windows 95 that incorporated a number of Internet-focused features and support for new types of devices.
In 2001 Microsoft released Windows XP, the first version that encompassed the features of both its business and home product lines.
Windows Vista and Microsoft Office 2007 were released in January 2007.
On 27.06.2008 Bill Gates retired from day-to day activities in the company, following a two year transition period from his role as Chief Software Architect, but remained the company's Chairman, and Head of the Board of Directors, continuing to act as an adviser on key projects.
On 22.10.2009 Windows 7 was officially released to the public. Microsoft preferred to refine Vista with ease of use features and performance enhancements, rather than to undertake a large reworking of Windows.
The company also markets both computer hardware products such as the
Microsoft mouse and the
Microsoft Natural keyboard, and home entertainment products such as
the Xbox,
Xbox 360, and
MSN TV.
Apple Inc. is a USA multinational corporation that designs and manufactures consumer electronics, computer software, and personal computers. The company's best-known hardware products include Macintosh computers, the iPod, the iPhone and the iPad. Apple software include the Apple Mac operating system OS X and iTunes.
Apple was founded in Cupertino, California on 01.04.1976 by Steve Jobs and Steve Wozniak and incorporated January 3, 03.01.1977, as Apple Computer Inc.. The word "Computer" was dropped from the name on 09.01.2007 to reflect the company's ongoing expansion into the consumer electronics market in addition to its traditional focus on personal computers.
The first machine announced was the Apple I personal computer kit (1976), hand-built by Wozniak. It was sold as a motherboard with CPU, RAM, and basic textual-video chips.
Apple II was introduced on 16.04.1977. It differed from its major rivals, the Tandy TRS-80 and Commodore PET, because it had colour graphics and an open architecture. Early models of the Apple II used audio cassette tapes as storage devices, but later they were superseded by the introduction of a 5 1/4 inch floppy disk drive and interface. The Apple II was chosen to be the desktop platform for the first VisiCalc spreadsheet application.
The company introduced the Apple III in May 1980 in an attempt to compete with IBM and Microsoft in the business and corporate computing market, but this was unsuccessful.
The Apple Lisa (1983) was the first personal computer sold to the public with a Graphical User Interface (GUI), but was a commercial failure due to its high price tag and limited software titles.
The first Apple Macintosh was released in 1984. It sold well initially, but follow-up sales were not strong because of the high price tag, as well as limited software titles. The machine's fortunes changed with the introduction of the LaserWriter, the first PostScript laser printer to be offered at a reasonable price point, and PageMaker, an early desktop publishing package. The Mac was particularly powerful in this market due to its advanced graphics capabilities, which were already necessarily built-in to create the intuitive Macintosh GUI. It has been suggested that the combination of these three products was responsible for the creation of the desktop publishing market.
In 1985 Jobs was removed from his managerial duties.He resigned from Apple and founded NeXT Inc. the same year, which produced
the NeXT Computer.
The bulky Macintosh Portable (1989) was not a success, but then Apple introduced the PowerBook (1991), which established the modern form and ergonomic layout of the laptop computer.
Microsoft continued to gain market share with its Windows OS, focusing on delivering software to cheap commodity personal computers, but Apple continued to produce richly engineered, but expensive, computers and consequently lost market share. Apple sued Microsoft for using a graphical user interface similar to the Apple Lisa in Apple Computer, Inc. v. Microsoft Corporation. The lawsuit dragged on for years before it was thrown out of court.
In 1994, Apple allied with IBM and Motorola in the AIM alliance. The goal was to create a new computing platform (the PowerPC Reference Platform), which would use IBM and Motorola hardware coupled with Apple's software. The AIM alliance hoped that PReP's performance and Apple's software would leave the PC far behind, thus countering Microsoft. The same year, Apple introduced the Power Macintosh, the first of many Apple computers to use IBM's PowerPC processor.
In 1996 the Apple management chose to purchase NeXT and its NeXTSTEP operating system, bringing Steve Jobs back to Apple as an advisor. In 1997 Jobs became the interim CEO and began restructuring the company's product line. Steve Jobs announced that Apple would join Microsoft to release new versions of Microsoft Office for the Macintosh. In 2005 Steve Jobs announced that Apple would begin producing Intel-based Mac computers in 2006, and the new MacBook Pro and
iMac became the first Apple computers to use Intel's Core Duo CPU.
Although Apple's market share in computers has grown, it remains far behind competitor Microsoft, with only about 8 percent of desktops and laptops in the USA. In 2007 Jobs announced that Apple Computer Inc. would from that point on be known as Apple Inc. because computers were just one part of the company now. This change reflects the company's focus from personal computersto mobile electronic devices, such as the iPhone, Apple TV, iTunes, iPhone and iPod.
Compaq Computer Corporation was a USA personal computer company founded in 1982 by three senior managers from semiconductor manufacturer Texas Instruments. The name "COMPAQ" was derived from "COMPatibility And Quality", and Compaq produced some of the first IBM PC compatible microcomputers.
In March 1983 Compaq produced their first product, the Compaq Portable, one of the precursors of the laptop; some people called it a "suitcase computer" from its size and the look of its case.
In June 1984 the Compaq Deskpro appeared, a 16-bit desktop computer using an Intel 8086 microprocessor running at 7.14 MHz. It was considerably faster than an IBM PC and was, like the Compaq Portable, also capable of running IBM software. This was the first of the Compaq Deskpro line of computers.
The 1986 Compaq Deskpro 386 was the first PC based on Intel's new 80386 microprocessor, and this began a period of increasing performance leadership over IBM, who were not yet using this processor. An IBM machine eventually reached the market seven months later, but by then Compaq was the 386 supplier of choice and IBM had lost its image of technical leadership.
In late 1989 this was followed by the Compaq Systempro Server.
In the early 1990s Compaq entered the retail computer market with the Compaq Presario.
In 1998 Compaq bought Digital Equipment Corporation, the leading company in the previous generation of minicomputers during the 1970s and early 1980s. This acquisition made Compaq the second largest computer maker in the world in terms of revenue. Unfortunately the company still struggled against lower-cost competitors such as Dell.
In 2001 Compaq merged with Hewlett-Packard (HPQ). By 2005, HPQ had retrieved the number one sales position from Dell. Most Compaq products have been re-branded with the HP nameplate.
Sun Microsystems Inc. , founded 1982 by Stanford graduate students, is a wholly owned subsidiary of the Oracle Corporation, selling computers, computer components, computer software, and information technology services. The SUN name is derived from the initials of the Stanford University Network. The headquarters are in Santa Clara, California, part of Silicon Valley.
Sun products include computer servers and workstations based on its own SPARC microprocessors and other chip sets, storage systems, the Solaris operating system, developer tools, web infrastructure software, and the Java platform.
The initial design for the Sun-1, a Unix-based workstation appeared in 1982. Early networks used high-end Sun servers and ORACLE software.
SPARC (from Scalable Processor ARChitecture) is a RISC architecture based on the SPARC microprocessor developed by Sun Microsystems and introduced in 1986.
1986 Sun SPARC workstation
However, in the difficult trading conditions following the technology bubble crash many companies, including Google, built web applications based on large numbers of the less expensive PC-class x86-architecture servers running Linux, rather than a smaller number of high-end Sun servers (benefits include lower acquisition and maintenance expenses and the use of open-source software). Sun responded to this in several ways, including its own line of x86-based servers, development of Solaris on the x86 platform, and release of the open-source OpenSolaris.
In 2004/2005 Sun concentrated on microprocessors optimized for multi-threading and multiprocessing, such as the "Niagara" UltraSPARC T1 microprocessor and a collaboration with Fujitsu to use Japanese microprocessor chips in the M-Series, part of the SPARC Enterprise series.
In February 2005, Sun announced the Sun Grid, using thousands of servers for utility processing and storage under the name Software as a Service product. This was one of the first manifestations of Cloud Computing.
Dell Inc. is a multinational information technology corporation that develops, sells and supports computers and related products and services. The company was founded in 1984 by Michael Dell while he was still a student at the University of Texas at Austin. Michael Dell started trading in the belief that by selling personal computer systems directly to customers the company could better understand customers' needs and provide the most effective computing solutions to meet those needs.
In 1985 the company produced the Turbo PC, the first computer of its own design.
The company changed its name to Dell Computer Corporation in 1988.
In 1996 Dell began selling computers via its web site.
In 2003, at the annual company meeting, the stockholders approved changing the company name to Dell Inc. to recognize the company's expansion beyond computers.
2005 Dell Dimension desk top
2007 Dell Inspiron desk top
2010 Dell Inspiron laptop
Companies are listed in order of date of foundation.
An Enigma machine is any of a family of related electromechanical rotor machines used for the encryption and decryption of secret messages.
The 1918 Scherbius patent
The first Enigma was invented by German engineer Arthur Scherbius at the end of World War I. This model and its variants were used commercially from the early 1920s, e.g. for the encryption of bank financial transactions, and then adopted by the military and government services of several countries, most notably by Nazi Germany during the Spanish Civil War and World War II. The traffic was not just naval, army and air force messages, but government, security, border and even railway messages. A range of Enigma models were produced, but the
German military model, the Wehrmacht Enigma (3 rotors), is the version most commonly discussed.
Enigma Kriegsmarine naval model (4 rotors)
The typical Enigma circuitry, involving (from the top) rotors, lamps, keyboard, and plugboard
Box of spare rotors
Plugboard for interchanging pairs of letters
The Enigma machines have become well-known because, during World War II, British and American crytographers were able, following pioneering Polish work, to read a vast number of messages which had been enciphered using the Enigma. The intelligence gleaned from this source, codenamed ULTRA by the British, was a substantial aid to the Allied war effort. It is stated that the decryption of German ciphers hastened the end of the European war by two years.
Though the Enigma cipher had cryptographic weaknesses (chiefly that a letter could never be encrypted into itself), in practice it was only in combination with other factors (procedural flaws, operator mistakes and habits, occasionally captured hardware and key tables, etc.) that those weaknesses allowed Allied cryptographers to decrypt so many messages. The setting up of the Enigma machines was changed daily. However, the Germans did not often change the system of encipherment, partly because they were convinced that the number of possible encryptions (3 x 10^20) was so large that decryption was impossible within a time which would render the information useful to an enemy. Alan Turing designed the Turing Bombe to help find the daily key settings.
The British Typex Machine was designed to use the daily Enigma settings to decrypt transmissions received by the Y stations (encrypted five-letter groups) into plain language German, and included features derived from the original Enigma patents.
Very much more complicated encryption machines were introduced in the later phases of World War II, including the
Lorenz machine which had 12 rotors, and employed a symmetrical Baudot code to encrypt very high security messages from the High Command. The Colossus machine, designed by Alan Turing and Tommy Flowers was constructed at Bletchley Park to decrypt these messages.
Konrad Zuse,working in his parents' apartment in 1936, constructed the Z1, a binary electromechanical calculator with limited programmability, reading instructions from a punched paper tape. In 1937 Zuse submitted two patents that anticipated a von Neumann architecture. He finished the Z1 in 1938, but it never worked well, due to the lack of sufficiently precise mechanical parts (cf. Charles Babbage's problems). The Z1 and its original blueprints were destroyed during World War II.
In 1939 Zuse was called for military service, where he was given the resources to ultimately build the Z2, a secret project of the German government, a revised version of the Z1, from telephone relays. The same year, he started a company, Zuse Apparatebau (Zuse Apparatus Engineering), to manufacture his machines. Special electromechanical computers, the S1 and S2, were mandated by the Henschel aircraft company in 1942/43. These were specialised machines for calculating profiles of the wings of aircraft. The S1 employed approximately 600 relays and had hard-wired programs. The S2 was the successor of the S1, and consisted of approximately 800 relays and about 100 output dials giving values for profile points on the wings. The S2 can be regarded as the first process-controlled computer in the world, and one of the first analog-to-digital converters. It was used to help develop the Henschel Werke HS-293 and HS-294 winged flying bombs, predecessors to modern cruise missiles.
Zuse in front of his Z3 machine
Z3 input/output display
Improving on the basic Z2 machine, Zuse built the Z3 in 1941, partially financed by German government-supported DVL (Deutsche Versuchsanstalt für Luftfahrt, German Experimentation-Institution for Aviation), which wanted their extensive calculations automated. The Z3 is considered his greatest achievement, a contender for the world's first functional program-controlled Turing-complete computer. It was a binary 22-bit floating point calculator featuring memory, a programmability function with loops but without conditional jumps, and a calculation unit using switching relays. The program was stored on punched film stock, but had no conditional branch instruction. Plans for an electronic successor to the Z3 using thermionic vacuum tubes as switching elements were stated by the German Government to be "strategically unimportant" which of course was a mistake. Zuse's company (with the Z3) was destroyed in 1945 by an Allied attack. A rebuild in 1998 with a conditional branch instruction demonstrated that the Z3 could have been a truly Turing complete computer.
In addition to his technical work, Zuse founded one of the earliest computer businesses in 1946. Fortunately, the partially finished, relay-based Z4, which Zuse had began constructing in 1942, had been moved to a safe place before the aerial attack. The company then built a commercial version of the Z4 (1950). It had 64 32-bit registers (0.5K of memory), and an addition took 0.4s.
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Version: 02 01 June 2010 updated by Dr John Wilcock