Article by hi joiney
(7483, ‘History of computing Main article History of computing hardware The Jacquard loom on display at the Museum of Science and Industry in Manchester England was one of the first programmable devices The first use of the word computer was recorded in 1613 referring to a person who carried out calculations or computations and the word continued to be used in that sense until the middle of the 20th century From the end of the 19th century onwards though the word began to take on its more familiar meaning describing a machine that carries out computations The history of the modern computer begins with two separate technologiesutomated calculation and programmabilityut no single device can be identified as the earliest computer partly because of the inconsistent application of that term Examples of early mechanical calculating devices include the abacus the slide rule and arguably the astrolabe and the Antikythera mechanism which dates from about 150100 BC Hero of Alexandria c 1070 AD built a mechanical theater which performed a play lasting 10 160 minutes and was operated by a complex system of ropes and drums that might be considered to be a means of deciding which parts of the mechanism performed which actions and when This is the essence of programmability The castle clock an astronomical clock invented by Al Jazari in 1206 is considered to be the earliest programmable analog computer It displayed the zodiac the solar and lunar orbits a crescent moon shaped pointer travelling across a gateway causing automatic doors to open every hour and five robotic musicians who played music when struck by levers operated by a camshaft attached to a water wheel The length of day and night could be re programmed to compensate for the changing lengths of day and night throughout the year The Renaissance saw a re invigoration of European mathematics and engineering Wilhelm Schickard s 1623 device was the first of a number of mechanical calculators constructed by European engineers but none fit the modern definition of a computer because they could not be programmed In 1801 Joseph Marie Jacquard made an improvement to the textile loom by introducing a series of punched paper cards as a template which allowed his loom to weave intricate patterns automatically The resulting Jacquard loom was an important step in the development of computers because the use of punched cards to define woven patterns can be viewed as an early albeit limited form of programmability It was the fusion of automatic calculation with programmability that produced the first recognizable computers In 1837 Charles Babbage was the first to conceptualize and design a fully programmable mechanical computer his analytical engine Limited finances and Babbage s inability to resist tinkering with the design meant that the device was never completed In the late 1880s Herman Hollerith invented the recording of data on a machine readable medium Prior uses of machine readable media above had been for control not data After some initial trials with paper tape he settled on punched cards 160 To process these punched cards he invented the tabulator and the keypunch machines These three inventions were the foundation of the modern information processing industry Large scale automated data processing of punched cards was performed for the 1890 United States Census by Hollerith s company which later became the core of IBM By the end of the 19th century a number of technologies that would later prove useful in the realization of practical computers had begun to appear the punched card Boolean algebra the vacuum tube thermionic valve and the teleprinter During the first half of the 20th century many scientific computing needs were met by increasingly sophisticated analog computers which used a direct mechanical or electrical model of the problem as a basis for computation However these were not programmable and generally lacked the versatility and accuracy of modern digital computers Alan Turing is widely regarded to be the father of modern computer science In 1936 Turing provided an influential formalisation of the concept of the algorithm and computation with the Turing machine Of his role in the modern computer Time magazine in naming Turing one of the 100 most influential people of the 20th century states The fact remains that everyone who taps at a keyboard opening a spreadsheet or a word processing program is working on an incarnation of a Turing machine The inventor of the program controlled computer was Konrad Zuse who built the first working computer in 1941 and later in 1955 the first computer based on magnetic storage George Stibitz is internationally recognized as a father of the modern digital computer While working at Bell Labs in November 1937 Stibitz invented and built a relay based calculator he dubbed the Model K for kitchen table on which he had assembled it which was the first to use binary circuits to perform an arithmetic operation Later models added greater sophistication including complex arithmetic and programmability Defining characteristics of some early digital computers of the 1940s In the history of computing hardware Name First operational Numeral system Computing mechanism Programming Turing complete Zuse Z3 Germany May 1941 Binary Electro mechanical Program controlled by punched film stock but no conditional branch Yes 1998 Atanasofferry Computer US 1942 Binary Electronic Not programmableingle purpose No Colossus Mark 1 UK February 1944 Binary Electronic Program controlled by patch cables and switches No Harvard Mark I IBM ASCC US May 1944 Decimal Electro mechanical Program controlled by 24 channel punched paper tape but no conditional branch No Colossus Mark 2 UK June 1944 Binary Electronic Program controlled by patch cables and switches No ENIAC US July 1946 Decimal Electronic Program controlled by patch cables and switches Yes Manchester Small Scale Experimental Machine Baby UK June 1948 Binary Electronic Stored program in Williams cathode ray tube memory Yes Modified ENIAC US September 1948 Decimal Electronic Program controlled by patch cables and switches plus a primitive read only stored programming mechanism using the Function Tables as program ROM Yes EDSAC UK May 1949 Binary Electronic Stored program in mercury delay line memory Yes Manchester Mark 1 UK October 1949 Binary Electronic Stored program in Williams cathode ray tube memory and magnetic drum memory Yes CSIRAC Australia November 1949 Binary Electronic Stored program in mercury delay line memory Yes A succession of steadily more powerful and flexible computing devices were constructed in the 1930s and 1940s gradually adding the key features that are seen in modern computers The use of digital electronics largely invented by Claude Shannon in 1937 and more flexible programmability were vitally important steps but defining one point along this road as the first digital electronic computer is difficult Shannon 1940 Notable achievements include EDSAC was one of the first computers to implement the stored program von Neumann architecture Die of an Intel 80486DX2 microprocessor actual size 126 75 160 mm in its packaging Konrad Zuse s electromechanical Z machines The Z3 1941 was the first working machine featuring binary arithmetic including floating point arithmetic and a measure of programmability In 1998 the Z3 was proved to be Turing complete therefore being the world s first operational computer The non programmable Atanasofferry Computer 1941 which used vacuum tube based computation binary numbers and regenerative capacitor memory The use of regenerative memory allowed it to be much more compact then its peers being approximately the size of a large desk or workbench since intermediate results could be stored and then fed back into the same set of computation elements The secret British Colossus computers 1943 which had limited programmability but demonstrated that a device using thousands of tubes could be reasonably reliable and electronically reprogrammable It was used for breaking German wartime codes The Harvard Mark I 1944 a large scale electromechanical computer with limited programmability The U S Army s Ballistic Research Laboratory ENIAC 1946 which used decimal arithmetic and is sometimes called the first general purpose electronic computer since Konrad Zuse s Z3 of 1941 used electromagnets instead of electronics Initially however ENIAC had an inflexible architecture which essentially required rewiring to change its programming Several developers of ENIAC recognizing its flaws came up with a far more flexible and elegant design which came to be known as the stored program architecture or von Neumann architecture This design was first formally described by John von Neumann in the paper First Draft of a Report on the EDVAC distributed in 1945 A number of projects to develop computers based on the stored program architecture commenced around this time the first of these being completed in Great Britain The first to be demonstrated working was the Manchester Small Scale Experimental Machine SSEM or Baby while the EDSAC completed a year after SSEM was the first practical implementation of the stored program design Shortly thereafter the machine originally described by von Neumann s paperDVACas completed but did not see full time use for an additional two years Nearly all modern computers implement some form of the stored program architecture making it the single trait by which the word computer is now defined While the technologies used in computers have changed dramatically since the first electronic general purpose computers of the 1940s most still use the von Neumann architecture Computers using vacuum tubes as their electronic elements were in use throughout the 1950s but by the 1960s had been largely replaced by transistor based machines which were smaller faster cheaper to produce required less power and were more reliable The first transistorised computer was demonstrated at the University of Manchester in 1953 In the 1970s integrated circuit technology and the subsequent creation of microprocessors such as the Intel 4004 further decreased size and cost and further increased speed and reliability of computers By the late 1970s many products such as video recorders contained dedicated computers called microcontrollers and they started to appear as a replacement to mechanical controls in domestic appliances such as washing machines The 1980s witnessed home computers and the now ubiquitous personal computer With the evolution of the Internet personal computers are becoming as common as the television and the telephone in the household citation needed Modern smartphones are fully programmable computers in their own right and as of 2009 may well be the most common form of such computers in existence citation needed Stored program architecture Main articles Computer program and Computer programming The defining feature of modern computers which distinguishes them from all other machines is that they can be programmed That is to say that a list of instructions the program can be given to the computer and it will store them and carry them out at some time in the future In most cases computer instructions are simple add one number to another move some data from one location to another send a message to some external device etc These instructions are read from the computer s memory and are generally carried out executed in the order they were given However there are usually specialized instructions to tell the computer to jump ahead or backwards to some other place in the program and to carry on executing from there These are called jump instructions or branches Furthermore jump instructions may be made to happen conditionally so that different sequences of instructions may be used depending on the result of some previous calculation or some external event Many computers directly support subroutines by providing a type of jump that remembers the location it jumped from and another instruction to return to the instruction following that jump instruction Program execution might be likened to reading a book While a person will normally read each word and line in sequence they may at times jump back to an earlier place in the text or skip sections that are not of interest Similarly a computer may sometimes go back and repeat the instructions in some section of the program over and over again until some internal condition is met This is called the flow of control within the program and it is what allows the computer to perform tasks repeatedly without human intervention Comparatively a person using a pocket calculator can perform a basic arithmetic operation such as adding two numbers with just a few button presses But to add together all of the numbers from 1 to 1 000 would take thousands of button presses and a lot of timeith a near certainty of making a mistake On the other hand a computer may be programmed to do this with just a few simple instructions For example mov 0 sum set sum to 0 mov 1 num set num to 1 loop add num sum add num to sum add 1 num add 1 to num cmp num 1000 compare num to 1000 ble loop if num lt 1000 go back to loop halt end of program stop running Once told to run this program the computer will perform the repetitive addition task without further human intervention It will almost never make a mistake and a modern PC can complete the task in about a millionth of a second However computers cannot think for themselves in the sense that they only solve problems in exactly the way they are programmed to An intelligent human faced with the above addition task might soon realize that instead of actually adding up all the numbers one can simply use the equation and arrive at the correct answer 500 500 with little work In other words a computer programmed to add up the numbers one by one as in the example above would do exactly that without regard to efficiency or alternative solutions Programs A 1970s punched card containing one line from a FORTRAN program The card reads Z 1 Y W 1 and is labelled PROJ039 for identification purposes In practical terms a computer program may run from just a few instructions to many millions of instructions as in a program for a word processor or a web browser A typical modern computer can execute billions of instructions per second gigahertz or GHz and rarely make a mistake over many years of operation Large computer programs consisting of several million instructions may take teams of programmers years to write and due to the complexity of the task almost certainly contain errors Errors in computer programs are called bugs Bugs may be benign and not affect the usefulness of the program’)
The film Man & Computer, made in 1965 by IBM’s UK branch, provides a basic understanding of computer operations. A large portion of the film shows the ways in which a computer can be simulated by five people using the standard office equipment of the day. The film employs a number of different techniques, including animations, and features a few brief scenes of an IBM System/360 in use—just months after the first machines were delivered. Starting in the 1940s, IBM became a major producer of films used for sales, training, documenting business processes, entertaining at company functions, and educating the public. Several IBM films were made by respected filmmakers and sometimes featured well-known actors.
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