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Distance along a scale, rotation of a shaft, or a voltage. Numbers could also be represented in the form of digits, automatically manipulated by a mechanism. Although this approach generally required more complex mechanisms, it greatly increased the precision of results. The development of transistor technology and then the integrated circuit chip led to a series of breakthroughs, starting with transistor computers and then integrated circuit computers, causing digital computers to largely replace analog computers.
Metal-oxide-semiconductor MOS large-scale integration LSI then enabled semiconductor memory and the microprocessor, leading to another key breakthrough, the miniaturized personal computer PCin the 1970s. The cost of computers gradually became so low that personal computers by the 1990s, and then mobile computers smartphones and tablets in the 2000s, became ubiquitous. 1 Early devices 1. 1 Ancient and medieval 1. 2 Renaissance calculating tools 1. 3 Mechanical calculators 1. 4 Punched-card data processing 1.
5 Calculators 2 First general-purpose computing device 3 Analog computers 4 Advent of the digital computer 4. 1 Electromechanical computers 4. 2 Digital computation 4. 3 Electronic data processing 4. 4 The electronic programmable computer 5 Stored-program computer 5. 2 Manchester Baby 5. 3 Manchester Mark 1 5. 6 Commercial computers 5. 7 Microprogramming 6 Magnetic memory 7 Early digital computer characteristics 8 Transistor computers 8. Before the 20th century, most calculations were done by humans.
2 Transistor supercomputers 9 Integrated circuit computers 10 Semiconductor memory 11 Microprocessor computers 12 Epilogue 13 See also 14 Notes 15 References 16 Further reading 17 External links. Ancient and medieval Edit. Devices have been used to aid computation for thousands of years, mostly using one-to-one correspondence with fingers.
The earliest counting device was probably a form of tally stick. The Lebombo bone from the mountains between Swaziland and South Africa may be the oldest known mathematical artifact. 2 It dates from 35,000 BCE and consists of 29 distinct notches that were deliberately cut into a baboon s fibula. 3 4 Later record keeping aids throughout the Fertile Crescent included calculi clay spheres, cones, etc. which represented counts of items, probably livestock or grains, sealed in hollow unbaked clay containers.
5 6 7 The use of counting rods is one example. The abacus was early used for arithmetic tasks. What we now call the Roman abacus was used in Babylonia as early as c. 2700 2300 BC. Since then, many other forms of reckoning boards or tables have been invented. In a medieval European counting house, a checkered cloth would be placed on a table, and markers moved around on it according to certain rules, as an aid to calculating sums of money. Several analog computers were constructed in ancient and medieval times to perform astronomical calculations.
1 Transistor peripherals 8. These included the astrolabe and Antikythera mechanism from the Hellenistic world c. 8 In Roman Egypt, Hero of Alexandria c. 10 70 AD made mechanical devices including automata and a programmable cart. 9 Other early mechanical devices used to perform one or another type of calculations include the planisphere and other mechanical computing devices invented by Abu Rayhan al-Biruni c.
AD 1000 ; the equatorium and universal latitude-independent astrolabe by Abū Ishāq Ibrāhīm al-Zarqālī c. AD 1015 ; the astronomical analog computers of other medieval Muslim astronomers and engineers; and the astronomical clock tower of Su Song 1094 during the Song dynasty. The castle clock, a hydropowered mechanical astronomical clock invented by Ismail al-Jazari in 1206, was the first programmable analog computer. 10 11 12 Ramon Llull invented the Lullian Circle a notional machine for calculating answers to philosophical questions in this case, to do with Christianity via logical combinatorics.
This idea was taken up by Leibniz centuries later, and is thus one of the founding elements in computing and information science. Renaissance calculating tools Edit. Scottish mathematician and physicist John Napier discovered that the multiplication and division of numbers could be performed by the addition and subtraction, respectively, of the logarithms of those numbers. While producing the first logarithmic tables, Napier needed to perform many tedious multiplications.
Since real numbers can be represented as distances or intervals on a line, the slide rule was invented in the 1620s, shortly after Napier s work, to allow multiplication and division operations to be carried out significantly faster than was previously possible. It was at this point that he designed his Napier s bonesan abacus-like device that greatly simplified calculations that involved multiplication and division.
14 Edmund Gunter built a calculating device with a single logarithmic scale at the University of Oxford. His device greatly simplified arithmetic calculations, including multiplication and division. William Oughtred greatly improved this in 1630 with his circular slide rule. He followed this up with the modern slide rule in 1632, essentially a combination of two Gunter rules, held together with the hands.
Slide rules were used by generations of engineers and other mathematically involved professional workers, until the invention of the pocket calculator. Mechanical calculators Edit. Wilhelm Schickard, a German polymath, designed a calculating machine in 1623 which combined a mechanised form of Napier s rods with the world s first mechanical adding machine built into the base. 16 A fire destroyed at least one of the machines in 1624 and it is believed Schickard was too disheartened to build another.
Because it made use of a single-tooth gear there were circumstances in which its carry mechanism would jam. 18 19 He built twenty of these machines called Pascal s calculator or Pascaline in the following ten years. In 1642, while still a teenager, Blaise Pascal started some pioneering work on calculating machines and after three years of effort and 50 prototypes 17 he invented a mechanical calculator.
20 Nine Pascalines have survived, most of which are on display in European museums. 21 A continuing debate exists over whether Schickard or Pascal should be regarded as the inventor of the mechanical calculator and the range of issues to be considered is discussed elsewhere. He attempted to create a machine that could be used not only for addition and subtraction but would utilise a moveable carriage to enable long multiplication and division.
Leibniz once said It is unworthy of excellent men to lose hours like slaves in the labour of calculation which could safely be relegated to anyone else if machines were used. Gottfried Wilhelm von Leibniz invented the stepped reckoner and his famous stepped drum mechanism around 1672. 23 However, Leibniz did not incorporate a fully successful carry mechanism. Leibniz also described the binary numeral system, 24 a central ingredient of all modern computers.
However, up to the 1940s, many subsequent designs including Charles Babbage s machines of the 1822 and even ENIAC of 1945 were based on the decimal system. Around 1820, Charles Xavier Thomas de Colmar created what would over the rest of the century become the first successful, mass-produced mechanical calculator, the Thomas Arithmometer. It could be used to add and subtract, and with a moveable carriage the operator could also multiply, and divide by a process of long multiplication and long division.
26 It utilised a stepped drum similar in conception to that invented by Leibniz. Punched-card data processing Edit. In 1804, French weaver Joseph Marie Jacquard developed a loom in which the pattern being woven was controlled by a paper tape constructed from punched cards. The paper tape could be changed without changing the mechanical design of the loom.
This was a landmark achievement in programmability. His machine was an improvement over similar weaving looms. Mechanical calculators remained in use until the 1970s. These bands would inspire information recording for automatic pianos and more recently numerical control machine tools. In the late 1880s, the American Herman Hollerith invented data storage on punched cards that could then be read by a machine.
Punched cards were preceded by punch bands, as in the machine proposed by Basile Bouchon. 27 To process these punched cards, he invented the tabulator and the keypunch machine. 28 Hollerith s method was used in the 1890 United States Census. That census was processed two years faster than the prior census had been. 29 Hollerith s company eventually became the core of IBM.
By 1920, electromechanical tabulating machines could add, subtract, and print accumulated totals. 30 Machine functions were directed by inserting dozens of wire jumpers into removable control panels. When the United States instituted Social Security in 1935, IBM punched-card systems were used to process records of 26 million workers. 31 Punched cards became ubiquitous in industry and government for accounting and administration.
Leslie Comrie s articles on punched-card methods and W. Eckert s publication of Punched Card Methods in Scientific Computation in 1940, described punched-card techniques sufficiently advanced to solve some differential equations 32 or perform multiplication and division using floating point representations, all on punched cards and unit record machines. The Astronomical Computing Bureau, Columbia University, performed astronomical calculations representing the state of the art in computing.
Calculators Edit. The word computer was a job title assigned to primarily women who used these calculators to perform mathematical calculations. 35 By the 1920s, British scientist Lewis Fry Richardson s interest in weather prediction led him to propose human computers and numerical analysis to model the weather; to this day, the most powerful computers on Earth are needed to adequately model its weather using the Navier Stokes equations.
Companies like Friden, Marchant Calculator and Monroe made desktop mechanical calculators from the 1930s that could add, subtract, multiply and divide. 37 In 1948, the Curta was introduced by Austrian inventor Curt Herzstark. The world s first all-electronic desktop calculator was the British Bell Punch ANITA, released in 1961.
It was a small, hand-cranked mechanical calculator and as such, a descendant of Gottfried Leibniz s Stepped Reckoner and Thomas s Arithmometer. By the 20th century, earlier mechanical calculators, cash registers, accounting machines, and so on were redesigned to use electric motors, with gear position as the representation for the state of a variable.
The ANITA sold well since it was the only electronic desktop calculator available, and was silent and quick. The tube technology was superseded in June 1963 by the U. 38 39 It used vacuum tubes, cold-cathode tubes and Dekatrons in its circuits, with 12 cold-cathode Nixie tubes for its display. manufactured Friden EC-130, which had an all-transistor design, a stack of four 13-digit numbers displayed on a 5-inch 13 cm CRT, and introduced reverse Polish notation RPN.
Charles Babbage, an English mechanical engineer and polymath, originated the concept of a programmable computer. Considered the father of the computer40 he conceptualized and invented the first mechanical computer in the early 19th century. After working on his revolutionary difference engine, designed to aid in navigational calculations, in 1833 he realized that a much more general design, an Analytical Engine, was possible.
The input of programs and data was to be provided to the machine via punched cards, a method being used at the time to direct mechanical looms such as the Jacquard loom. For output, the machine would have a printer, a curve plotter and a bell. The machine would also be able to punch numbers onto cards to be read in later. It employed ordinary base-10 fixed-point arithmetic.
The Engine incorporated an arithmetic logic unit, control flow in the form of conditional branching and loops, and integrated memory, making it the first design for a general-purpose computer that could be described in modern terms as Turing-complete. There was to be a store, or memory, capable of holding 1,000 numbers of 40 decimal digits each ca. An arithmetical unit, called the millwould be able to perform all four arithmetic operations, plus comparisons and optionally square roots.
Initially it was conceived as a difference engine curved back upon itself, in a generally circular layout, 43 with the long store exiting off to one side. Later drawings depict a regularized grid layout. Such machines were used during World War II for cryptographic statistical processing, as well as a vast number of administrative uses.
44 Like the central processing unit CPU in a modern computer, the mill would rely on its own internal procedures, roughly equivalent to microcode in modern CPUs, to be stored in the form of pegs inserted into rotating drums called barrelsto carry out some of the more complex instructions the user s program might specify. The programming language to be employed by users was akin to modern day assembly languages.
Loops and conditional branching were possible, and so the language as conceived would have been Turing-complete as later defined by Alan Turing. Three different types of punch cards were used one for arithmetical operations, one for numerical constants, and one for load and store operations, transferring numbers from the store to the arithmetical unit or back.
There were three separate readers for the three types of cards. The machine was about a century ahead of its time. However, the project was slowed by various problems including disputes with the chief machinist building parts for it. All the parts for his machine had to be made by hand this was a major problem for a machine with thousands of parts. Eventually, the project was dissolved with the decision of the British Government to cease funding. Babbage s failure to complete the analytical engine can be chiefly attributed to difficulties not only of politics and financing, but also to his desire to develop an increasingly sophisticated computer and to move ahead faster than anyone else could follow.
Ada Lovelace translated and added notes to the Sketch of the Analytical Engine by Luigi Federico Menabrea. This appears to be the first published description of programming, so Ada Lovelace is widely regarded as the first computer programmer. He independently designed a programmable mechanical computer, which he described in a work that was published in 1909. In the first half of the 20th century, analog computers were considered by many to be the future of computing.
Following Babbage, although unaware of his earlier work, was Percy Ludgate, a clerk to a corn merchant in Dublin, Ireland. These devices used the continuously changeable aspects of physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved, in contrast to digital computers that represented varying quantities symbolically, as their numerical values change.
As an analog computer does not use discrete values, but rather continuous values, processes cannot be reliably repeated with exact equivalence, as they can with Turing machines. The first modern analog computer was a tide-predicting machine, invented by Sir William Thomson, later Lord Kelvin, in 1872. It used a system of pulleys and wires to automatically calculate predicted tide levels for a set period at a particular location and was of great utility to navigation in shallow waters.
His device was the foundation for further developments in analog computing. The differential analyser, a mechanical analog computer designed to solve differential equations by integration using wheel-and-disc mechanisms, was conceptualized in 1876 by James Thomson, the brother of the more famous Lord Kelvin. He explored the possible construction of such calculators, but was stymied by the limited output torque of the ball-and-disk integrators. 51 In a differential analyzer, the output of one integrator drove the input of the next integrator, or a graphing output.
An important advance in analog computing was the development of the first fire-control systems for long range ship gunlaying. When gunnery ranges increased dramatically in the late 19th century it was no longer a simple matter of calculating the proper aim point, given the flight times of the shells. Various spotters on board the ship would relay distance measures and observations to a central plotting station.
There the fire direction teams fed in the location, speed and direction of the ship and its target, as well as various adjustments for Coriolis effect, weather effects on the air, and other adjustments; the computer would then output a firing solution, which would be fed to the turrets for laying. In 1912, British engineer Arthur Pollen developed the first electrically powered mechanical analogue computer called at the time the Argo Clock. His machines used electromechanical relays and counters.
citation needed It was used by the Imperial Russian Navy in World War I. citation needed The alternative Dreyer Table fire control system was fitted to British capital ships by mid-1916. Mechanical devices were also used to aid the accuracy of aerial bombing. Drift Sight was the first such aid, developed by Harry Wimperis in 1916 for the Royal Naval Air Service; it measured the wind speed from the air, and used that measurement to calculate the wind s effects on the trajectory of the bombs.
The system was later improved with the Course Setting Bomb Sight, and reached a climax with World War II bomb sights, Mark XIV bomb sight RAF Bomber Command and the Norden 52 United States Army Air Forces. The art of mechanical analog computing reached its zenith with the differential analyzer, 53 built by H. Hazen and Vannevar Bush at MIT starting in 1927, which built on the mechanical integrators of James Thomson and the torque amplifiers invented by H. A dozen of these devices were built before their obsolescence became obvious; the most powerful was constructed at the University of Pennsylvania s Moore School of Electrical Engineering, where the ENIAC was built.
A fully electronic analog computer was built by Helmut Hölzer in 1942 at Peenemünde Army Research Center. By the 1950s the success of digital electronic computers had spelled the end for most analog computing machines, but hybrid analog computers, controlled by digital electronics, remained in substantial use into the 1950s and 1960s, and later in some specialized applications.
The principle of the modern computer was first described by computer scientist Alan Turing, who set out the idea in his seminal 1936 paper, 57 On Computable Numbers. Turing reformulated Kurt Gödel s 1931 results on the limits of proof and computation, replacing Gödel s universal arithmetic-based formal language with the formal and simple hypothetical devices that became known as Turing machines. He proved that some such machine would be capable of performing any conceivable mathematical computation if it were representable as an algorithm.
He went on to prove that there was no solution to the Entscheidungsproblem by first showing that the halting problem for Turing machines is undecidable in general, it is not possible to decide algorithmically whether a given Turing machine will ever halt. He also introduced the notion of a universal machine now known as a universal Turing machinewith the idea that such a machine could perform the tasks of any other machine, or in other words, it is provably capable of computing anything that is computable by executing a program stored on tape, allowing the machine to be programmable.
Von Neumann acknowledged that the central concept of the modern computer was due to this paper. 58 Turing machines are to this day a central object of study in theory of computation. Except for the limitations imposed by their finite memory stores, modern computers are said to be Turing-complete, which is to say, they have algorithm execution capability equivalent to a universal Turing machine. Electromechanical computers Edit. The era of modern computing began with a flurry of development before and during World War II.
These devices had a low operating speed and were eventually superseded by much faster all-electric computers, originally using vacuum tubes. Most digital computers built in this period were electromechanical electric switches drove mechanical relays to perform the calculation. The Z2 was one of the earliest examples of an electromechanical relay computer, and was created by German engineer Konrad Zuse in 1940.
It was an improvement on his earlier Z1; although it used the same mechanical memory, it replaced the arithmetic and control logic with electrical relay circuits. In the same year, electro-mechanical devices called bombes were built by British cryptologists to help decipher German Enigma-machine-encrypted secret messages during World War II. The bombe s initial design was created in 1939 at the UK Government Code and Cypher School GC CS at Bletchley Park by Alan Turing, 60 with an important refinement devised in 1940 by Gordon Welchman.
61 The engineering design and construction was the work of Harold Keen of the British Tabulating Machine Company. It was a substantial development from a device that had been designed in 1938 by Polish Cipher Bureau cryptologist Marian Rejewski, and known as the cryptologic bomb Polish bomba kryptologiczna. 63 The Z3 was built with 2000 relays, implementing a 22-bit word length that operated at a clock frequency of about 5 10 Hz.
In 1941, Zuse followed his earlier machine up with the Z3, 62 the world s first working electromechanical programmable, fully automatic digital computer. 64 Program code and data were stored on punched film. It was quite similar to modern machines in some respects, pioneering numerous advances such as floating point numbers.
Replacement of the hard-to-implement decimal system used in Charles Babbage s earlier design by the simpler binary system meant that Zuse s machines were easier to build and potentially more reliable, given the technologies available at that time. 65 The Z3 was probably a Turing-complete machine. In two 1936 patent applications, Zuse also anticipated that machine instructions could be stored in the same storage used for data the key insight of what became known as the von Neumann architecture, first implemented in 1948 in America in the electromechanical IBM SSEC and in Britain in the fully electronic Manchester Baby.
Zuse suffered setbacks during World War II when some of his machines were destroyed in the course of Allied bombing campaigns. Apparently his work remained largely unknown to engineers in the UK and US until much later, although at least IBM was aware of it as it financed his post-war startup company in 1946 in return for an option on Zuse s patents. In 1944, the Harvard Mark I was constructed at IBM s Endicott laboratories; 67 it was a similar general purpose electro-mechanical computer to the Z3, but was not quite Turing-complete.
Digital computation Edit. The term digital was first suggested by George Robert Stibitz and refers to where a signal, such as a voltage, is not used to directly represent a value as it would be in an analog computerbut to encode it. In November 1937, George Stibitz, then working at Bell Labs 1930 194168 completed a relay-based calculator he later dubbed the Model K for k itchen tableon which he had assembled itwhich became the first binary adder.
69 Typically signals have two states low usually representing 0 and high usually representing 1but sometimes three-valued logic is used, especially in high-density memory. Modern computers generally use binary logic, but many early machines were decimal computers. In these machines, the basic unit of data was the decimal digit, encoded in one of several schemes, including binary-coded decimal or BCD, bi-quinary, excess-3, and two-out-of-five code.
The mathematical basis of digital computing is Boolean algebra, developed by the British mathematician George Boole in his work The Laws of Thoughtpublished in 1854. His Boolean algebra was further refined in the 1860s by William Jevons and Charles Sanders Peirce, and was first presented systematically by Ernst Schröder and A. 70 In 1879 Gottlob Frege develops the formal approach to logic and proposes the first logic language for logical equations.
In the 1930s and working independently, American electronic engineer Claude Shannon and Soviet logician Victor Shestakov both showed a one-to-one correspondence between the concepts of Boolean logic and certain electrical circuits, now o iq option logic gates, which are now ubiquitous in digital computers. 72 They showed 73 that electronic relays and switches can realize the expressions of Boolean algebra.
This thesis essentially founded practical digital circuit design. Electronic data processing Edit. Purely electronic circuit elements soon replaced their mechanical and electromechanical equivalents, at the same time that digital calculation replaced analog. Machines such as the Z3, the Atanasoff Berry Computer, the Colossus computers, and the ENIAC were built by hand, using circuits containing relays or valves vacuum tubesand often used punched cards or punched paper tape for input and as the main non-volatile storage medium.
The engineer Tommy Flowers joined the telecommunications branch of the General Post Office in 1926. While working at the research station in Dollis Hill in the 1930s, he began to explore the possible use of electronics for the telephone exchange. Experimental equipment that he built in 1934 went into operation 5 years later, converting a portion of the telephone exchange network into an electronic data processing system, using thousands of vacuum tubes.
75 This calculating device was fully electronic control, calculations and output the first electronic display. In the US, in 1940 Arthur Dickinson IBM invented the first digital electronic computer. 76 John Vincent Atanasoff and Clifford E. Berry of Iowa State University developed the Atanasoff Berry Computer ABC in 1942, 77 the first binary electronic digital calculating device. 78 This design was semi-electronic electro-mechanical control and electronic calculationsand used about 300 vacuum tubes, with capacitors fixed in a mechanically rotating drum for memory.
However, its paper card writer reader was unreliable and the regenerative drum contact system was mechanical. The machine s special-purpose nature and lack of changeable, stored program distinguish it from modern computers. Computers whose logic was primarily built using vacuum tubes are now known as first generation computers. The electronic programmable computer Edit. During World War II, British codebreakers at Bletchley Park, 40 miles 64 km north of London, achieved a number of successes at breaking encrypted enemy military communications.
The German encryption machine, Enigma, was first attacked with the help of the electro-mechanical bombes. 80 Women often operated these bombe machines. 81 82 They ruled out possible Enigma settings by performing chains of logical deductions implemented electrically. Most possibilities led to a contradiction, and the few remaining could be tested by hand.
The Germans also developed a series of teleprinter encryption systems, quite different from Enigma. The Lorenz SZ 40 42 machine was o iq option for high-level Army communications, code-named Tunny by the British. The first intercepts of Lorenz messages began in 1941. As part of an attack on Tunny, Max Newman and his colleagues developed the Heath Robinson, a fixed-function machine to aid in code breaking.
83 Tommy Flowers, a senior engineer at the Post Office Research Station 84 was recommended to Max Newman by Alan Turing 85 and spent eleven months from early February 1943 designing and building the more flexible Colossus computer which superseded the Heath Robinson. 86 87 After a functional test in December 1943, Colossus was shipped to Bletchley Park, where it was delivered on 18 January 1944 88 and attacked its first message on 5 February.
Colossus was the world s first electronic digital programmable computer. 50 It used a large number of valves vacuum tubes. Data input to Colossus was by photoelectric reading of a paper tape transcription of the enciphered intercepted message. It had paper-tape input and was capable of being configured to perform a variety of boolean logical operations on its data, 90 but it was not Turing-complete. This was arranged in a continuous loop so that it could be read and re-read multiple times there being no internal store for the data.
The reading mechanism ran at 5,000 characters per second with the paper tape moving at 40 ft s 12. Colossus Mark 1 contained 1500 thermionic valves tubesbut Mark 2 with 2400 valves and five processors in parallel, was both 5 times faster and simpler to operate than Mark 1, greatly speeding the decoding process. Mark 2 was designed while Mark 1 was being constructed. Allen Coombs took over leadership of the Colossus Mark 2 project when Tommy Flowers moved on to other projects.
91 The first Mark 2 Colossus became operational on 1 June 1944, just in time for the Allied Invasion of Normandy on D-Day. Most of the use of Colossus was in determining the start positions of the Tunny rotors for a message, which was called wheel setting. Colossus included the first-ever use of shift registers and systolic arrays, enabling five simultaneous tests, each involving up to 100 Boolean calculations.
This enabled five different possible start positions to be examined for one transit of the paper tape. 92 As well as wheel setting some later Colossi included mechanisms intended to help determine pin patterns known as wheel breaking. Both models were programmable using switches and plug panels in a way their predecessors had not been. Ten Mk 2 Colossi were operational by the end of the war. Without the use of these machines, the Allies would have been deprived of the very valuable intelligence that was obtained from reading the vast quantity of enciphered high-level telegraphic messages between the German High Command OKW and their army commands throughout occupied Europe.
Details of their existence, design, and use were kept secret well into the 1970s. Winston Churchill personally issued an order for their destruction into pieces no larger than a man s hand, to keep secret that the British were capable of cracking Lorenz SZ cyphers from German rotor stream cipher machines during the oncoming Cold War. Two of the machines were transferred to the newly formed GCHQ and the others were destroyed.
As a result, the machines were not included in many histories of computing. 94 A reconstructed working copy of one of the Colossus machines is now on display at Bletchley Park. The US-built ENIAC Electronic Numerical Integrator and Computer was the first electronic programmable computer built in the US. Although the ENIAC was similar to the Colossus it was much faster and more flexible. It was unambiguously a Turing-complete device and could compute any problem that would fit into its memory.
Like the Colossus, a program on the ENIAC was defined by the states of its patch cables and switches, a far cry from the stored program electronic machines that came later. Once a program was written, it had to be mechanically set into the machine with manual resetting of plugs and switches. The programmers of the ENIAC were women who had been trained as mathematicians.
It combined the high speed of electronics with the ability to be programmed for many complex problems. It could add or subtract 5000 times a second, a thousand times faster than any other machine. It also had modules to multiply, divide, and square root. Built under the direction of John Mauchly and J. Presper Eckert at the University of Pennsylvania, ENIAC s development and construction lasted from 1943 to full operation at the end of 1945. The machine was huge, weighing 30 tons, using 200 kilowatts of electric power and contained over 18,000 vacuum tubes, 1,500 relays, and hundreds of thousands of resistors, capacitors, and inductors.
96 One of its major engineering feats was to minimize the effects of tube burnout, which was a common problem in machine reliability at that time. The machine was in almost constant use for the next ten years. Early computing machines were programmable in the sense that they could follow the sequence of steps they had been set up to execute, but the programor steps that the machine was to execute, were set up usually by changing how the wires were plugged into a patch panel or plugboard.
Reprogrammingwhen it was possible at all, was a laborious process, starting with engineers working out flowcharts, designing the new set up, and then the often-exacting process of physically re-wiring patch panels. 97 Stored-program computers, by contrast, were designed to store a set of instructions a programin memory typically the same memory as stored data.
Theory Edit. The theoretical basis for the stored-program computer had been proposed by Alan Turing in his 1936 paper. In 1945 Turing joined the National Physical Laboratory and began his work on developing an electronic stored-program digital computer. His 1945 report Proposed Electronic Calculator was the first specification for such a device. Meanwhile, John von Neumann at the Moore School of Electrical Engineering, University of Pennsylvania, circulated his First Draft of a Report on the EDVAC in 1945.
Although substantially similar to Turing s design and containing comparatively little engineering detail, the computer architecture it outlined became known as the von Neumann architecture. Turing presented a more detailed paper to the National Physical Laboratory NPL Executive Committee in 1946, giving the first reasonably complete design of a stored-program computer, a device he called the Automatic Computing Engine ACE. However, the better-known EDVAC design of John von Neumann, who knew of Turing s theoretical work, received more publicity, despite its incomplete nature and questionable lack of attribution of the sources of some of the ideas.
Turing thought that the speed and the size of computer memory were crucial elements, so he proposed a high-speed memory of what would today be called 25 KB, accessed at a speed of 1 MHz. The ACE implemented subroutine calls, whereas the EDVAC did not, and the ACE also used Abbreviated Computer Instructions, an early form of programming language. Manchester Baby Edit. The Manchester Baby was the world s first electronic stored-program computer.
It was built at the Victoria University of Manchester by Frederic C. Williams, Tom Kilburn and Geoff Tootill, and ran its first program on 21 June 1948. The machine was not intended to be a practical computer but was instead designed as a testbed for the Williams tube, the first random-access digital storage device. 99 Invented by Freddie Williams and Tom Kilburn 100 101 at the University of Manchester in 1946 and 1947, it was a cathode ray tube that used an effect called secondary emission to temporarily store electronic binary data, and was used successfully in several early computers.
Although the computer was small and primitive by the standards of the 1990s, it was the first working machine to contain all of the elements essential to a modern electronic computer. 102 As soon as the Baby had demonstrated the feasibility of its design, a project was initiated at the university to develop it into a more usable computer, the Manchester Mark 1.
The Mark 1 in turn quickly became the prototype for the Ferranti Mark 1, the world s first commercially available general-purpose computer. The Baby had a 32-bit word length and a memory of 32 words. As it was designed to be the simplest possible stored-program computer, the only arithmetic operations implemented in hardware were subtraction and negation; other arithmetic operations were implemented in software. The first of three programs written for the machine found the highest proper divisor of 2 18 262,144a calculation that was known would take a long time to run and so prove the computer s reliability by testing every integer from 2 18 1 downwards, as division was implemented by repeated subtraction of the divisor.
The program consisted of 17 instructions and ran for 52 minutes before reaching the correct answer of 131,072, after the Baby had performed 3. 5 million operations for an effective CPU speed of 1. Manchester Mark 1 Edit. The Experimental machine led on to the development of the Manchester Mark 1 at the University of Manchester.
104 Work began in August 1948, and the first version was operational by April 1949; a program written to search for Mersenne primes ran error-free for nine hours on the night of 16 17 June 1949. The machine s successful operation was widely reported in the British press, which used the phrase electronic brain in describing it to their readers. The computer is especially historically significant because of its pioneering inclusion of index registers, an innovation which made it easier for a program to read sequentially through an array of words in memory.
Thirty-four patents resulted from the machine s development, and many of the ideas behind its design were incorporated in subsequent commercial products such as the IBM 701 and 702 as well as the Ferranti Mark 1. The chief designers, Frederic C. Williams and Tom Kilburn, concluded from their experiences with the Mark 1 that computers would be used more in scientific roles than in pure mathematics.
In 1951 they started development work on Meg, the Mark 1 s successor, o iq option would include a floating point unit. The other contender for being the first recognizably modern digital stored-program computer 105 was the EDSAC, 106 designed and constructed by Maurice Wilkes and his team at the University of Cambridge Mathematical Laboratory in England at the University of Cambridge in 1949.
The machine was inspired by John von Neumann s seminal First Draft of a Report on the EDVAC and was one of the first usefully operational electronic digital stored-program computer. High-speed memory was limited to 20 words equivalent to about 80 bytes. EDSAC ran its first programs on 6 May 1949, when it calculated a table of squares 108 and a list of prime numbers.
The EDSAC also served as the basis for the first commercially applied computer, the LEO I, used by food manufacturing company J. EDSAC 1 and was finally shut down on 11 July 1958, having been superseded by EDSAC 2 which stayed in use until 1965. The brain computer may one day come down to our level of the common people and help with our income-tax and book-keeping calculations. But this is speculation and there is no sign of it so far. ENIAC inventors John Mauchly and J. Presper Eckert proposed the EDVAC s construction in August 1944, and design work for the EDVAC commenced at the University of Pennsylvania s Moore School of Electrical Engineering, before the ENIAC was fully operational.
The design implemented a number of important architectural and logical improvements conceived during the ENIAC s construction, and a high-speed serial-access memory. 111 However, Eckert and Mauchly left the project and its construction floundered. Army s Ballistics Research Laboratory at the Aberdeen Proving Ground in August 1949, but due to a number of problems, the computer only began operation in 1951, and then only on a limited basis.
It was finally delivered to the U. Commercial computers Edit. The first commercial computer was the Ferranti Mark 1, built by Ferranti and delivered to the University of Manchester in February 1951. It was based on the Manchester Mark 1. The main improvements over the Manchester Mark 1 were in the size of the primary storage using random access Williams tubessecondary storage using a magnetic druma faster multiplier, and additional instructions. The basic cycle time was 1.
2 milliseconds, and a multiplication could be completed in about 2. 16 milliseconds. The multiplier used almost a quarter of the machine s 4,050 vacuum tubes valves. 112 A second machine was purchased by the University of Toronto, before the design was revised into the Mark 1 Star. At least seven of these later machines were delivered between 1953 and 1957, one of them to Shell labs in Amsterdam. In October 1947, the directors of J. Lyons Company, a British catering company famous for its teashops but with strong interests in new office management techniques, decided to take an active role in promoting the commercial development of computers.
The LEO I computer became operational in April 1951 114 and ran the world s first regular routine office computer job. On 17 November 1951, the J. Lyons company began weekly operation of a bakery valuations job on the LEO Lyons Electronic Office. This was the first business application to go live on a stored program computer. In June 1951, the UNIVAC I Universal Automatic Computer was delivered to the U. Remington Rand eventually sold 46 machines at more than US 1 million each 9.
85 million as of 2020. 116 UNIVAC was the first mass produced computer. It used 5,200 vacuum tubes and consumed 125 kW of power. Its primary storage was serial-access mercury delay lines capable of storing 1,000 words of 11 decimal digits plus sign 72-bit words. IBM introduced a smaller, more affordable computer in 1954 that proved very popular. 117 The IBM 650 weighed over 900 kg, the attached power supply weighed around 1350 kg and both were held in separate cabinets of roughly 1.
5 meters by 0. 9 meters by 1. It cost US 500,000 118 4. 76 million as of 2020 or could be leased for US 3,500 a month 30 o iq option as of 2020. 116 Its drum memory was originally 2,000 ten-digit words, later expanded to 4,000 words. Memory limitations such as this were to dominate programming for decades afterward. The program instructions were fetched from the spinning drum as the code ran. Efficient execution using drum memory was provided by a combination of hardware architecture the instruction format included the address of the next instruction; and software the Symbolic Optimal Assembly Program, SOAP, 119 assigned instructions to the optimal addresses to the extent possible by static analysis of the source program.
Thus many instructions were, when needed, located in the next row of the drum to be read and additional wait time for drum rotation was not required. Microprogramming Edit. In 1951, British scientist Maurice Wilkes developed the concept of microprogramming from the realisation that the central processing unit of a computer could be controlled by a miniature, highly specialised computer program in high-speed ROM.
120 This concept greatly simplified CPU development. Microprogramming allows the base instruction set to be defined or extended by built-in programs now called firmware or microcode. He first described this at the University of Manchester Computer Inaugural Conference in 1951, then published in expanded form in IEEE Spectrum in 1955. It was widely used in the CPUs and floating-point units of mainframe and other computers; it was implemented for the first time in EDSAC 2, 121 which also used multiple identical bit slices to simplify design.
Interchangeable, replaceable tube assemblies were used for each bit of the processor. Magnetic drum memories were developed for the US Navy during WW II with the work continuing at Engineering Research Associates ERA in 1946 and 1947. ERA, then a part of Univac included a drum memory o iq option its 1103, announced in February 1953. The first mass-produced computer, the IBM 650, also announced in 1953 had about 8. Magnetic core memory patented in 1949 123 with its first usage demonstrated for the Whirlwind computer in August 1953.
5 kilobytes of drum memory. 124 Commercialization followed quickly. Magnetic core was used in peripherals of the IBM 702 delivered in July 1955, and later in the 702 itself. The IBM 704 1955 and the Ferranti Mercury 1957 used magnetic-core memory. It went on to dominate the field into the 1970s, when it was replaced with semiconductor memory. Magnetic core peaked in volume about 1975 and declined in usage and market share thereafter.
As late as 1980, PDP-11 45 machines using magnetic-core main memory and drums for swapping were still in use at many of the original UNIX sites.
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