From the end of the 19th century the word began to take on its more familiar meaning, a machine that carries out computations. [3] Mechanical aids to computing The history of the modern computer begins with two separate technologies, automated calculation and programmability. However no single device can be identified as the earliest computer, partly because of the inconsistent application of that term. 4] A few precursors are worth mentioning though, like some mechanical aids to computing, which were very successful and survived for centuries until the advent of the electronic calculator, like the Sumerian abacus, designed around 2500 BC[5] of which a descendant won a speed competition against a contemporary desk alculating machine in Japan in 1946,[6] the slide rules, invented in the 1620s, which were carried on five Apollo space missions, including to the moon[7] and arguably the astrolabe and the Antikythera mechanism, an ancient astronomical analog computer built by the Greeks around 80 BC. 8] The Greek mathematician Hero of Alexandria (c. 10-70 AD) built a mechanical theater which performed a play lasting 10 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. 9] This is the essence of programmability. Mechanical calculators and programmable looms The Most Famous Image in the Early History of Computing[10] This portrait of Jacquard was woven in silk on a Jacquard loom and required 24,000 punched cards to create (1839).
It was only produced to order. Charles Babbage started exhibiting this portrait in 1840 to explain how his analytical engine would work. [11] Blaise Pascal invented the mechanical calculator in known as Pascal''s calculator, it was the first machine to better human performance of mechanical calculator in the 17th century. 14] Two hundred years later, in 1851, Thomas de Colmar released, after thirty years of development, his simplified arithmometer; it became the first machine to be commercialized because it was strong enough and reliable enough to be used daily in an office environment.
The mechanical calculator was at the root of the development of computers in two separate ways. Initially, it was in trying to develop more powerful and more flexible calculators[1 5] that the computer was first theorized by Charles and then developed. [18] Secondly, development of a low-cost electronic calculator, uccessor to the mechanical calculator, resulted in the development by Intel[19] of the first commercially available microprocessor integrated circuit.
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. First use of punched paper cards in computing
It was the fusion of automatic calculation with programmability that produced the first recognizable computers. In 1837, Charles Babbage, "the actual father of the computer",[20] was the first to conceptualize and design a fully programmable mechanical calculator,[21] his analytical engine. [22] Babbage started in 1834, initially he was to program his analytical engine with drums similar to the ones used in Vaucanson''s automata which by design were limited in size, but soon he replaced them by Jacquard'' s card readers, one for data and one for program. The introduction of punched cards into the new engine was important not only as a more onvenient form of control than the drums, or because programs could now be of unlimited extent, and could be stored and repeated without the danger of introducing errors in setting the machine by hand; it was important also because it served to crystallize Babbage''s feeling that he had invented something really new, something much more than a sophisticated calculating machine. "[23] Now it is obvious that no finite machine can include infinity... t is impossible to construct machinery occupying unlimited space; but it is possible to construct finite machinery, and to use it through unlimited time. It is this substitution of the infinity of time for the infinity of space which I have made use of, to limit the size of the engine and yet to retain its unlimited power. —Charles Babbage, Passages from the Life of a Philosopher, Chapter VIII: On the Analytical Engine[24] programmable) incorporating his new ideas. Allan Bromley came to the science museum of London starting in 1979 to study Babbage''s engines and determined that difference engine No. what the only engine that had a complete enough set of drawings to be built and he convinced the museum to do it. This engine, finished in 991, proved without doubt the validity of Charles Babbage work. [25] Except for a pause between 1848 and 1857, Babbage would spend the rest of his life simplifying each part of his engine: "Gradually he developed plans for Engines of great logical power and elegant simplicity (although the term ''simple'' is used here in a purely relative sense). [26] Ada Lovelace, considered to be the first computer programmer[27] Between 1842 and 1843, Ada Lovelace, an analyst of Charles Babbage''s analytical engine, translated an article by Italian military engineer Luigi Menabrea on the engine, which she upplemented with an elaborate set of notes of her own. These notes contained what is considered the first computer program - that is, an algorithm encoded for processing by a machine. She also stated: "We may say most aptly, that the Analytical Engine weaves algebraical patterns Just as the Jacquard-loom weaves flowers and leaves. ; furthermore she developed a vision on the capability of computers to go beyond mere calculating or number-crunching[28] claiming that: should "... the fundamental relations of pitched sounds in the science of harmony and of musical composition... " be susceptible "... f adaptations to the action of the operating notation and mechanism of the engine... " it "... might compose elaborate and scientific pieces of music of any degree of complexity or extent". [29] In the late 1880s, Herman Hollerith invented the recording of data on a machine- readable medium.
Earlier uses of machine-readable media had been for control, not data. "After some initial trials with paper tape, he settled on punched cards... "[30] 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 18M.
By the end of the 19th century a number of ideas and technologies, that would later prove useful in the realization of practical computers, had begun to appear: Boolean algebra, the vacuum tube (thermionic valve), punched cards and tape, and the teleprinter. Babbage dream comes true In 1888, Henry Babbage, Charles Babbage''s son, completed a simplified version of the analytical engine''s computing unit (the mill) . He gave a successful demonstration of 9 decimal places. 31] This machine was given to the Science museum in South Kensington in 1910. He also gave a demonstration piece of one of his father''s engine to Harvard University which convinced Howard Aiken, 50 years later, to incorporate the architecture of the analytical engine in what will become the ASCC/Mark I built by IBM. [32] Leonardo Torres y Quevedo built two analytical machines to prove that all of the functions of Babbage''s analytical engine could be replaced with electromechanical devices.
The first one, built in 1914, had a little electromechanical memory and the econd one, built in 1920 to celebrate the one hundredth anniversary of the invention of the arithmometer, received its commands and printed its results on a typewriter. [33] Torres y Quevedo published functional schematics of all of these functions: addition, multiplication, division and even a decimal comparator, in his "Essais sur l''automatique" in 1915. Some inventors like Percy Ludgate, Vannevar Bush[33] and Louis Couffgnal[34] tried to improve on the analytical engine but didn''t succeed at building a machine.
Howard Aiken wanted to build a giant calculator and was looking for a sponsor to uild it. He first presented his design to the Monroe Calculator Company and then to Harvard University both without success. Carmello Lanza, a technician in Harvard''s physics laboratory who had heard Aiken''s presentation "... couldn''t see why in the world I (Howard Aiken) wanted to do anything like this in the Physics laboratory, because we already had such a machine and nobody used it...
Lanza led him up into the attic... There, sure enough... were the wheels that Aiken later put on display in the lobby of the Computer Laboratory. With them was a letter from Henry Prevost Babbage describing these wheels as part of his father''s proposed calculating engine. This was the first time Aiken ever heard of Babbage he said, and it was this experience that led him to look up Babbage in the library and to come across his autobiography"[32] which gave a description of his analytical engine. 24] Aiken first contacted IBM in November 1937,[35] presenting a machine which, by then, had an architecture based on Babbage''s analytical engine. This was the first developement of a programmable calculator that would succeed and that would end up being used for many years to come: the ASCC/Mark 1. 32] Zuse first heard of Aiken and IBM''s work from the German Secret Service. [36] He considered his Z3 to be a Babbage type machine. [37] First general-purpose computers automatic computing machine.
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 as the father of modern computer science. In 1936, Turing provided an influential formalization of the concept of the algorithm and computation with the Turing machine, providing a blueprint for the electronic digital computer. 38] Of his role in the creation of 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. "[38] The ENIAC, which became operational in 1946, is considered to be the first general- purpose electronic computer.
Programmers Betty Jean Jennings (left) and Fran Bilas (right) are depicted here operating the ENIAC''s main control panel. EDSAC was one of the first computers to implement the stored-program (von Neumann) architecture. The first really functional computer was the Zl , originally created by Germany''s Konrad Zuse in his parents'' living room in 1936 to 1938, and it is considered to be the first electro-mechanical binary programmable (modern) computer. [39] 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 elay-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. [40] The Atanasoff-Berry Computer (ABC) was the world''s first electronic digital computer, albeit not programmable. [41] Atanasoff is considered to be one of the fathers of the computer. 42] Conceived in 1937 by Iowa State College physics professor John Atanasoff, and built with the assistance of graduate student Clifford Berry,[43] the achine was not programmable, being designed only to solve systems of linear patent dispute found that the patent for the 1946 ENIAC computer derived from the Atanasoff-Berry Computer. The first program-controlled computer was invented by Konrad Zuse, who built the Z3, an electromechanical computing machine, in 1941. [44] The first programmable electronic computer was the Colossus, built in 1943 by Tommy Flowers.
Key steps towards modern computers 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: 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. [45] Thus, Zuse is often regarded as the nventor of the computer. [46][47][48][49] The non-programmable Atanasoff-Berry Computer (commenced in 1937, completed in 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 than 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),[50] which had limited programmability but demonstrated that a device using thousands of tubes could be reasonably reliable nd electronically re-programmable. It was used for breaking German wartime codes. The Harvard Mark I (1944), a large-scale electromechanical computer with limited programmability. 51] 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 architecture which required rewiring a plugboard to change its programming. Stored-program architecture Question book-new. svg This section does not cite any references or sources. Please help improve this section by adding citations to reliable sources.
Unsourced material may be challenged and removed. Ouly 2012) Several developers of ENIAC, recognizing its flaws, came up with a far more flexible 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 which was completed in 1948 at the University of Manchester in England, the Manchester Small-Scale Experimental Machine (SSEM or "Baby'').
The Electronic Delay Storage Automatic Calculator (EDSAC), completed a year after the SSEM at Cambridge University, was the first practical, non- experimental implementation of the stored-program design and was put to use immediately for research work at the university. Shortly thereafter, the machine originally described by von Neumann''s paper—EDVAC—was 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. Die of an Intel 80486DX2 microprocessor (actual size: 12x6. 75 mm) in its packaging Beginning in the 1950s, Soviet scientists Sergei Sobolev and Nikolay Brusentsov conducted research on ternary computers, devices that operated on a base three numbering system of-I, O, and 1 rather than the conventional binary numbering system upon which most computers are based.
They designed the Setun, a functional ternary computer, at Moscow State University. The device was put into limited production in the Soviet Union, but supplanted by the more common binary Semiconductors and microprocessors Computers using vacuum tubes as their electronic elements were in use throughout the 1950s, but by the 1960s they had been largely replaced by transistor-based machines, which were smaller, faster, cheaper to produce, required less power, and were more reliable. The first transistorized computer was demonstrated at the University of Manchester in 1953. 52] In the 1970s, integrated circuit technology and the subsequent creation of microprocessors, such as the Intel 4004, further ecreased 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 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] Programs Alan Turing was an influential computer scientist. The defining feature of modern computers which distinguishes them from all other machines is that they can be programmed. That is to say that some type of instructions (the program) can be given to the computer, and it will process them. Modern computers based on the von Neumann architecture often have machine code in the form of an imperative programming language.
In practical terms, a computer program may be Just a few instructions or extend to many millions of instructions, as do the programs for word processors and web rowsers for example. A typical modern computer can execute billions of instructions per second (gigaflops) and rarely makes 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.
Stored program architecture Main articles: Computer program and Computer programming Replica of the Small-Scale Experimental Machine (SSEM), the world''s first stored- program computer, at the Museum of Science and Industry in Manchester, England This section applies to most common RAM machine-based computers. 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 instructions (or branches). Furthermore, Jump instructions may be made to happen conditionally so that different sequences of instructions may be used depending on he 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 nd 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 time, with 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:
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