History of computing
History of computing 

Hardware 
Software 
Computer science 
Modern concepts 

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Timeline of computing 
Glossary of computer science 
The history of computing is longer than the history of computing hardware and modern computing technology and includes the history of methods intended for pen and paper or for chalk and slate, with or without the aid of tables.
Concrete devices
Digital computing is intimately tied to the representation of numbers.^{[1]} But long before abstractions like the number arose, there were mathematical concepts to serve the purposes of civilization. These concepts are implicit in concrete practices such as :
 onetoone correspondence,^{[2]} a rule to count how many items, say on a tally stick, eventually abstracted into numbers;
 comparison to a standard,^{[3]} a method for assuming reproducibility in a measurement, for example, the number of coins
 the 345 right triangle was a device for assuring a right angle, using ropes with 12 evenly spaced knots, for example.^{[4]}
Numbers
Eventually, the concept of numbers became concrete and familiar enough for counting to arise, at times with singsong mnemonics to teach sequences to others. All known languages have words for at least "one" and "two" (although this is disputed: see Piraha language), and even some animals like the blackbird can distinguish a surprising number of items.^{[5]}
Advances in the numeral system and mathematical notation eventually led to the discovery of mathematical operations such as addition, subtraction, multiplication, division, squaring, square root, and so forth. Eventually the operations were formalized, and concepts about the operations became understood well enough to be stated formally, and even proven. See, for example, Euclid's algorithm for finding the greatest common divisor of two numbers.
By the High Middle Ages, the positional Hindu–Arabic numeral system had reached Europe, which allowed for systematic computation of numbers. During this period, the representation of a calculation on paper actually allowed calculation of mathematical expressions, and the tabulation of mathematical functions such as the square root and the common logarithm (for use in multiplication and division) and the trigonometric functions. By the time of Isaac Newton's research, paper or vellum was an important computing resource, and even in our present time, researchers like Enrico Fermi would cover random scraps of paper with calculation, to satisfy their curiosity about an equation.^{[6]} Even into the period of programmable calculators, Richard Feynman would unhesitatingly compute any steps which overflowed the memory of the calculators, by hand, just to learn the answer.
Early computation
The earliest known tool for use in computation is the Sumerian abacus, and it was thought to have been invented in Babylon c. 2700–2300 BC. Its original style of usage was by lines drawn in sand with pebbles. Abaci, of a more modern design, are still used as calculation tools today. This was the first known computer and most advanced system of calculation known to date  preceding Greek methods by 2,000 years.
In c. 1050–771 BC, the southpointing chariot was invented in ancient China. It was the first known geared mechanism to use a differential gear, which was later used in analog computers. The Chinese also invented a more sophisticated abacus from around the 2nd century BC known as the Chinese abacus.
In the 5th century BC in ancient India, the grammarian Pāṇini formulated the grammar of Sanskrit in 3959 rules known as the Ashtadhyayi which was highly systematized and technical. Panini used metarules, transformations and recursions.^{[7]}
In the 3rd century BC, Archimedes used the mechanical principle of balance (see Archimedes Palimpsest#Mathematical content) to calculate mathematical problems, such as the number of grains of sand in the universe (The sand reckoner), which also required a recursive notation for numbers (e.g., the myriad myriad).
Around 200 BC the development of gears had made it possible to create devices in which the positions of wheels would correspond to positions of astronomical objects. By about 100 AD Hero of Alexandria had described an odometerlike device that could be driven automatically and could effectively count in digital form.^{[8]} But it was not until the 1600s that mechanical devices for digital computation appear to have actually been built.
The Antikythera mechanism is believed to be the earliest known mechanical analog computer.^{[9]} It was designed to calculate astronomical positions. It was discovered in 1901 in the Antikythera wreck off the Greek island of Antikythera, between Kythera and Crete, and has been dated to circa 100 BC.
Mechanical analog computer devices appeared again a thousand years later in the medieval Islamic world and were developed by Muslim astronomers, such as the mechanical geared astrolabe by Abū Rayhān alBīrūnī,^{[10]} and the torquetum by Jabir ibn Aflah.^{[11]} According to Simon Singh, Muslim mathematicians also made important advances in cryptography, such as the development of cryptanalysis and frequency analysis by Alkindus.^{[12]}^{[13]} Programmable machines were also invented by Muslim engineers, such as the automatic flute player by the Banū Mūsā brothers,^{[14]} and AlJazari's humanoid robots and castle clock, which is considered to be the first programmable analog computer.^{[15]}
During the Middle Ages, several European philosophers made attempts to produce analog computer devices. Influenced by the Arabs and Scholasticism, Majorcan philosopher Ramon Llull (1232–1315) devoted a great part of his life to defining and designing several logical machines that, by combining simple and undeniable philosophical truths, could produce all possible knowledge. These machines were never actually built, as they were more of a thought experiment to produce new knowledge in systematic ways; although they could make simple logical operations, they still needed a human being for the interpretation of results. Moreover, they lacked a versatile architecture, each machine serving only very concrete purposes. In spite of this, Llull's work had a strong influence on Gottfried Leibniz (early 18th century), who developed his ideas further, and built several calculating tools using them.
Indeed, when John Napier discovered logarithms for computational purposes in the early 17th century, there followed a period of considerable progress by inventors and scientists in making calculating tools. The apex of this early era of formal computing can be seen in the difference engine and its successor the analytical engine (which was never completely constructed but was designed in detail), both by Charles Babbage. The analytical engine combined concepts from his work and that of others to create a device that if constructed as designed would have possessed many properties of a modern electronic computer. These properties include such features as an internal "scratch memory" equivalent to RAM, multiple forms of output including a bell, a graphplotter, and simple printer, and a programmable inputoutput "hard" memory of punch cards which it could modify as well as read. The key advancement which Babbage's devices possessed beyond those created before his was that each component of the device was independent of the rest of the machine, much like the components of a modern electronic computer. This was a fundamental shift in thought; previous computational devices served only a single purpose, but had to be at best disassembled and reconfigured to solve a new problem. Babbage's devices could be reprogramed to solve new problems by the entry of new data, and act upon previous calculations within the same series of instructions. Ada Lovelace took this concept one step further, by creating a program for the analytical engine to calculate Bernoulli numbers, a complex calculation requiring a recursive algorithm. This is considered to be the first example of a true computer program, a series of instructions that act upon data not known in full until the program is run.
Several examples of analog computation survived into recent times. A planimeter is a device which does integrals, using distance as the analog quantity. Until the 1980s, HVAC systems used air both as the analog quantity and the controlling element. Unlike modern digital computers, analog computers are not very flexible, and need to be reconfigured (i.e., reprogrammed) manually to switch them from working on one problem to another. Analog computers had an advantage over early digital computers in that they could be used to solve complex problems using behavioral analogues while the earliest attempts at digital computers were quite limited.
Since computers were rare in this era, the solutions were often hardcoded into paper forms such as nomograms,^{[16]} which could then produce analog solutions to these problems, such as the distribution of pressures and temperatures in a heating system.
Digital electronic computers
The “brain” [computer] may one day come down to our level [of the common people] and help with our incometax and bookkeeping calculations. But this is speculation and there is no sign of it so far.
— British newspaper The Star in a June 1949 news article about the EDSAC computer, long before the era of the personal computers.^{[17]}
None of the early computational devices were really computers in the modern sense, and it took considerable advancement in mathematics and theory before the first modern computers could be designed.
The first recorded idea of using digital electronics for computing was the 1931 paper "The Use of Thyratrons for High Speed Automatic Counting of Physical Phenomena" by C. E. WynnWilliams.^{[18]} From 1934 to 1936, NEC engineer Akira Nakashima published a series of papers introducing switching circuit theory, using digital electronics for Boolean algebraic operations,^{[19]}^{[20]}^{[21]} influencing Claude Shannon's seminal 1938 paper "A Symbolic Analysis of Relay and Switching Circuits".^{[22]}
The 1937 Atanasoff–Berry computer design was the first digital electronic computer (though not programmable), and the Z3 computer from 1941, by German inventor Konrad Zuse was the first working programmable, fully automatic computing machine.
Alan Turing modelled computation in terms of a onedimensional storage tape, leading to the idea of the Turing machine and Turingcomplete programming systems.
During World War II, ballistics computing was done by women, who were hired as "computers." The term computer remained one that referred to mostly women (now seen as "operator") until 1945, after which it took on the modern definition of machinery it presently holds.^{[23]}
The ENIAC (Electronic Numerical Integrator And Computer) was the first electronic generalpurpose computer, announced to the public in 1946. It was Turingcomplete, digital, and capable of being reprogrammed to solve a full range of computing problems. Women implemented the programming for machines like the ENIAC, and men created the hardware.^{[23]}
The Manchester Baby was the first electronic storedprogram 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.^{[24]} The first storedprogram transistor computer was the ETL Mark III, developed by Japan's Electrotechnical Laboratory^{[25]}^{[26]}^{[27]} from 1954^{[28]} to 1956.^{[26]}
The microprocessor was introduced with the Intel 4004. It began with the "Busicom Project"^{[29]} as Masatoshi Shima's threechip CPU design in 1968,^{[30]}^{[29]} before Sharp's Tadashi Sasaki conceived of a singlechip CPU design, which he discussed with Busicom and Intel in 1968.^{[31]} The Intel 4004 was then developed as a singlechip microprocessor from 1969 to 1970, led by Intel's Marcian Hoff and Federico Faggin and Busicom's Masatoshi Shima.^{[29]} The microprocessor led to the development of microcomputers, and the microcomputer revolution.
The 1980s brought about significant advances with microprocessor that greatly impacted the fields of engineering and other sciences. The Motorola 68000 microprocessor had a processing speed that was far superior to the other microprocessors being used at the time. Because of this, having a newer, faster microprocessor allowed for the newer microcomputers that came along after to be more efficient in the amount of computing they were able to do. This was evident in the 1983 release of the Apple computer Lisa. Lisa was the first personal computer with graphical user interface (GUI) that was sold commercially, she ran on the Motorola 68000, dual floppy disk drives, a 5 MB hard drive and had 1MB of RAM .^{[32]} After successfully launching Lisa, a year later Apple released its first Macintosh computer still running on the Motorola 68000 microprocessor. Another advancement because of microprocessors came from Texas Instruments. Texas Instruments first introduced their TMS9900 processor in June 1976.^{[33]} They then used their microprocessor in their TI 99/4 computer.
Late 1980s and beginning in the early 1990s we see more advances with actual computers to aid with actual computing. In 1990, Apple released the Macintosh Portable, it was heavy weighing 7.3 kg (16 lb) and extremely expensive. It was not met with great success and was discontinued only two years later. That same year Intel introduced the Touchstone Delta supercomputer, which had 512 microprocessors. This technological advancement was very significant as it was used as a model for some of the fastest multiprocessors systems in the world. It was even used a prototype for Caltech researchers who used the model for projects like real time processing of satellite images and simulating molecular models for various fields of research.
Navigation and astronomy
Starting with known special cases, the calculation of logarithms and trigonometric functions can be performed by looking up numbers in a mathematical table, and interpolating between known cases. For small enough differences, this linear operation was accurate enough for use in navigation and astronomy in the Age of Exploration. The uses of interpolation have thrived in the past 500 years: by the twentieth century Leslie Comrie and W.J. Eckert systematized the use of interpolation in tables of numbers for punch card calculation.
Weather prediction
The numerical solution of differential equations, notably the NavierStokes equations was an important stimulus to computing, with Lewis Fry Richardson's numerical approach to solving differential equations. The first computerised weather forecast was performed in 1950 by a team composed of American meteorologists Jule Charney, Philip Thompson, Larry Gates, and Norwegian meteorologist Ragnar Fjørtoft, applied mathematician John von Neumann, and ENIAC programmer Klara Dan von Neumann.^{[34]}^{[35]}^{[36]} To this day, some of the most powerful computer systems on Earth are used for weather forecasts.
Symbolic computations
By the late 1960s, computer systems could perform symbolic algebraic manipulations well enough to pass collegelevel calculus courses.
See also
 Algorithm
 Charles Babbage Institute  research center for history of computing at University of Minnesota
 Computing timelines category
 History of software
 IT History Society
 List of mathematicians
 List of pioneers in computer science
 Timeline of quantum computing
References
 ↑ "Digital Computing  Dictionary definition of Digital Computing  Encyclopedia.com: FREE online dictionary". www.encyclopedia.com. Retrieved 20170911.
 ↑ OnetoOne Correspondence: Foundation Level
 ↑ Ifrah, Georges (2000), The Universal History of Numbers: From prehistory to the invention of the computer., John Wiley and Sons, p. 48, ISBN 0471393401
 ↑ W., Weisstein, Eric. "3, 4, 5 Triangle". mathworld.wolfram.com. Retrieved 20170911.
 ↑ Konrad Lorenz (1961). King Solomon's Ring. Translated by Marjorie Kerr Wilson. London: Methuen. ISBN 0416538606.
 ↑ "DIY: Enrico Fermi's Back of the Envelope Calculations".
 ↑ Sinha, A. C. (1978). "On the status of recursive rules in transformational grammar". Lingua. 44 (2–3): 169. doi:10.1016/00243841(78)900761.
 ↑ Wolfram, Stephen (2002). A New Kind of Science. Wolfram Media, Inc. p. 1107. ISBN 1579550088.
 ↑ The Antikythera Mechanism Research Project, The Antikythera Mechanism Research Project. Retrieved 20070701
 ↑ "Islam, Knowledge, and Science". University of Southern California. Archived from the original on 20080119. Retrieved 20080122.
 ↑ Lorch, R. P. (1976), "The Astronomical Instruments of Jabir ibn Aflah and the Torquetum", Centaurus, 20 (1): 11–34, Bibcode:1976Cent...20...11L, doi:10.1111/j.16000498.1976.tb00214.x
 ↑ Simon Singh, The Code Book, pp. 1420
 ↑ "AlKindi, Cryptgraphy, Codebreaking and Ciphers". Retrieved 20070112.
 ↑ Koetsier, Teun (2001), "On the prehistory of programmable machines: musical automata, looms, calculators", Mechanism and Machine Theory, Elsevier, 36 (5): 589–603, doi:10.1016/S0094114X(01)000052. .
 ↑ Ancient Discoveries, Episode 11: Ancient Robots, History Channel, archived from the original on March 1, 2014, retrieved 20080906
 ↑ Steinhaus, H. (1999). Mathematical Snapshots (3rd ed.). New York: Dover. pp. 92–95, p. 301.
 ↑
 ↑ WynnWilliams, C. E. (July 2, 1931), "The Use of Thyratrons for High Speed Automatic Counting of Physical Phenomena", Proceedings of the Royal Society A, 132 (819): 295–310, Bibcode:1931RSPSA.132..295W, doi:10.1098/rspa.1931.0102
 ↑ History of Research on Switching Theory in Japan, IEEJ Transactions on Fundamentals and Materials, Vol. 124 (2004) No. 8, pp. 720726, Institute of Electrical Engineers of Japan
 ↑ Switching Theory/Relay Circuit Network Theory/Theory of Logical Mathematics, IPSJ Computer Museum, Information Processing Society of Japan
 ↑ Radomir S. Stanković, Jaakko Astola (2008), Reprints from the Early Days of Information Sciences: TICSP Series On the Contributions of Akira Nakashima to Switching Theory, TICSP Series #40, Tampere International Center for Signal Processing, Tampere University of Technology
 ↑ Radomir S. Stanković (University of Niš), Jaakko T. Astola (Tampere University of Technology), Mark G. Karpovsky (Boston University), Some Historical Remarks on Switching Theory, 2007, DOI 10.1.1.66.1248
 1 2 Light, Jennifer S. (July 1999). "When Computers Were Women". Technology and Culture. 40: 455–483.
 ↑ Enticknap, Nicholas (Summer 1998), "Computing's Golden Jubilee", Resurrection, The Computer Conservation Society (20), ISSN 09587403, retrieved 19 April 2008
 ↑ Early Computers, Information Processing Society of Japan
 1 2 【Electrotechnical Laboratory】 ETL Mark III TransistorBased Computer, Information Processing Society of Japan
 ↑ Early Computers: Brief History, Information Processing Society of Japan
 ↑ Martin Fransman (1993), The Market and Beyond: Cooperation and Competition in Information Technology, page 19, Cambridge University Press
 1 2 3 Federico Faggin, The Making of the First Microprocessor, IEEE SolidState Circuits Magazine, Winter 2009, IEEE Xplore
 ↑ Nigel Tout. "The Busicom 141PF calculator and the Intel 4004 microprocessor". Retrieved November 15, 2009.
 ↑ Aspray, William (19940525). "OralHistory: Tadashi Sasaki". Interview #211 for the Center for the History of Electrical Engineering. The Institute of Electrical and Electronics Engineers, Inc. Retrieved 20130102.
 ↑ "Computers  Timeline of Computer History  Computer History Museum". www.computerhistory.org. Retrieved 20170905.
 ↑ Conner, Stuart. "Stuart's TM 990 Series 16bit Microcomputer Modules". www.stuartconner.me.uk. Retrieved 20170905.
 ↑ Charney, Fjörtoft and von Neumann, 1950, Numerical Integration of the Barotropic Vorticity Equation Tellus, 2, 237254
 ↑ Witman, Sarah (16 June 2017). "Meet the Computer Scientist You Should Thank For Your Smartphone's Weather App". Smithsonian. Retrieved 22 July 2017.
 ↑ Edwards, Paul N. (2010). A Vast Machine: Computer Models, Climate Data, and the Politics of Global Warming. The MIT Press. ISBN 9780262013925.
Important women and their contributions
 Ada Lovelace wrote the addendum to Babbage's Analytical Machine. Detailing, in poetic style, the first computer algorithm; a description of exactly how The Analytical Machine should have worked based on its design.
 Grace Murray Hopper is a pioneer of computing. She worked alongside Howard H. Aiken on the IBM's Mark I. Hopper also came up with the term "debugging."
 Hedy Lamarr invented a "frequency hopping" technology that was used by the Navy during World War II to control torpedoes via radio signals. This same technology is also used today in creating Bluetooth and Wifi signals.
 Frances Elizabeth "Betty" Holberton invented "breakpoints" which are mini pauses put into lines of computer code to help programmers easily detect, troubleshoot, and solve problems.
 Frances Elizabeth ("Fran") Allen
 Karen Spärck Jones was responsible for "inverse document frequency"  a concept that is most commonly used by search engines.
 Margaret Hamilton was the director of the Software Engineering Division at MIT which developed onboard flight software for the Apollo's Missions to Space.
 Barbara Liskov developed the "Liskov Substitution Principle."
 Radia Perlman invented the "Spanning Tree Protocol," a key network protocol used in Ethernet networks.
External links
 The History of Computing by J.A.N. Lee
 "Things that Count: the rise and fall of calculators"
 The History of Computing Project
 SIG on Computers, Information and Society of the Society for the History of Technology
 The Modern History of Computing
 Cringely's "Triumph of the Nerds"
 Top 25 Days in Computing History
 A Chronology of Digital Computing Machines (to 1952) by Mark Brader
 Bitsavers, an effort to capture, salvage, and archive historical computer software and manuals from minicomputers and mainframes of the 1950s, 60s, 70s, and 80s
 Cyberhistory (2002) by Keith Falloon. UWA digital thesis repository.
 Arithmometre.org, The reference about Thomas de Colmar's arithmometers
 Yahoo Computers and History
 "AllMagnetic Logic Computer". Timeline of Innovations. SRI International. Developed at SRI International in 1961
 Famous Names in the History of Computing. Free source for history of computing biographies.
 Stephen White's excellent computer history site (the above article is a modified version of his work, used with Permission)
 Soviet Digital Electronics Museum  a big collection of Soviet calculators, computers, computer mice and other devices
 Logarithmic timeline of greatest breakthroughs since start of computing era in 1623 by Jürgen Schmidhuber, from "The New AI: General & Sound & Relevant for Physics, In B. Goertzel and C. Pennachin, eds.: Artificial General Intelligence, p. 175198, 2006."
 IEEE computer history timeline
 Konrad Zuse, inventor of first working programmable digital computer by Jürgen Schmidhuber
 The Moore School Lectures and the British Lead in Stored Program Computer Development (1946–1953), article from Virtual Travelog
 Technology— andSociety/STS035Spring2004/CourseHome/index.htm MIT STS.035 — History of Computing from MIT OpenCourseWare for undergraduate level
 Key Resources in the History of Computing
 Italian computer database of brands
 Computer History  a collection of articles by Bob Bemer
 YouTube video comparing 1980s home computers to 2010s technology
 A visual timeline of the development of computers since COLOSSUS' inception in 1943
 History of Computing Visualization
 Computer Histories  An introductory course on the history of computing
British history links
 Resurrection Bulletin of the Computer Conservation Society (UK) 1990–2006
 The story of the Manchester Mark I, 50th Anniversary website at the University of Manchester
 Richmond Arabian History of Computing Group Linking the Gulf and Europe