History of computing

The earliest reference of the term computer comes from the French word of the same in 1631, derived from the Latin word computare meaning "to count, to sum up". The word is formed from the two roots: com- meaning "with", and +putare meaning "to reckon"(originally "to prune").

Early Devices

Before the arrival of mechanical or analogue computing, ancient civilizations required methods to quantify properties of their livelihoods. The earliest counting device, the Slamis Tablet, was discovered on the island of Salamis in 1846, and was used by the Babylonians to track numbers in their society. On this board, physical markers(indicators) were placed on the various rows or columns that represented different values. The indicators were not physically attached to the board.

Development of counting techniques lead to devices like the Roman hand abacus, which is estimated to have been created some time between 300 B.C. and 500 A.D. A notworthy advancement of the hand abacus was the implementation of permanently attached markers, which are adjusted in position to indicate value. This modification might have contributed to the evolution of the suan-pan, or Chinese abacus, in or around 1200 A.D.

The typical modern-day abacus has slidable markers are placed on columns of shafts(typically made from wood or metal) representing powers of ten (.0001, .001, .01, .1, 1, 10, 100 etc), with the top row representing values of "fives" and the bottom representing values of "ones". These markers are permanently attached to the device.

It should be noted that usage of an abacus relies on a concept of "states" and place values; that is--whether or not beads are in the "inclusive" or "not-inclusive" positions. To count items on an abacus, a number of beads are shifted over to the represented position that indicates a counted value, and any that are not moved are not counted.

Mechanical Computing

On 13 February 1967, the "Codex Madrid", written by Leonardo Da Vinci, was discovered in the National Library of Spain in Madrid. Inside the Codex Madrid was a drawing for an elaborate mechanical computational device, found by Dr. Roberto Guatelli, who noted that a similar construct appeared in Da Vinci's "Codex Atlanticus". A prototype of this machine was created in 1968, and was observed that it exhibited traits that of a ratio machine. One revolution of the first shaft(10^1) invoked ten revolutions of the second(10^2), repeating until the last shaft which rotated at a rate of ten to the power of 13.

Whether this was a true computational device was under some debate. Previously been displayed at IBM, the exhibit was removed due to a nonconsensus, and is presumed to be in one of IBM's storage facilities. The earliest recognized mechanical computational device is the Pascaline, created by Blaise Pascal circa 1642. The Pascaline performed simple addition and subtraction. The concept of the pascaline came about from the carrying of places by gear rotation. Functionally, the machine worked by increasing values on a single cog, which ranged from values 0 to 9. Upon the next rotation, a series of cogs would rotate the next gear over one iteration to read 1 while the first cog would reset back to 0.

It would take Charles Babbage, born on December 26, 1791 and inducted as a Fellow of the Royal Society to develop the first real successful automatic calculating machine. In 1821, Babbage developed the Difference Engine No. 1, which was a functional machine designed to compile mathematical tables based on polynomial caculation.. The difference engine's physical algorithm was based on a mathematical technique known as the Method of Differences, which Babbage contributed work on. Unfortunately only a fragment of the machine would ever come to fruitition due to various financial disputes and accusations of fund mismanagement from the British Government. More importantly, the machine was never fully developed due to Babbage's realization of a more improved machine called the Analytical Engine.

Functionally, the Analytical Engine was capable of various algorithmic operations that were broken down into basic algebraic operations. Two cards would be used to program the system: the first would detail what operations were required to be performed, and the second would contain the values to be operated on. In this sense, the Analytical Machine was much like a computer, having an input(the algorithm as described on a card), a processor(the machine), an output(the result), and memory(using a storage method--the cards themselves). Like the pascaline, both the Difference and Analytical Engines relied on series of cogs and gears to compute values.

Herman Hollerith was born on February 29, 1860 in New York. In 1875 Hollerith attended the City College of New York, he graduated from the Columbia School of Mines in 1879 with an engineering degree. After graduating, Hollerith took up work with the United States Census Bureau, and was appointed Chief Special Agent. Hollerith's contribution to computing was inspired by his work at the USCB, especially from Dr. John Shaw Billings who suggested that there should be a way to process the large amount of census data by some mechcanical means.

In 1884, Hollerith worked to develop a way to tabulate census information through the use of punch cards. Eventually, he recognized that cards could be used as storage medium for census data. His experiments lead to a process by where a pin would go through a hole in the card to complete an electrical circuit. His system by which cards could be read and tabulated on a mechanical counter through a circuit completion was called the Hollerith Electric Tabulating System. By 1890, the machines were improved so that a simple keyboard could be used to tabulate data instead of entry by hand.

Electrical Computing

In America, the development of an almost totally-autonomous system came about on August 7, 1944, when the IBM Automated Sequence Controlled Calculator(ASCC) was shipped and assembled that year to Harvard University, thereby earning its more popular name, the Harvard Mk I. It was widely accepted that the Harvard Mark I was the first electromechanical automatic digital calculator, until it was discovered that German engineer Konrad Zuse had developed the Z3 in 1941. Unfortunately this fact was discovered shortly after the end of World War II, and the photographs of the system were destroyed by allied raids. Consequently, later in life, Zuse would rebuild all of his machines; the Z1, originally created between 1936 and 1938; the Z2, created sometime between 1936 and 1939; and the Z3, contructed from 1939 to 1941.

The idea for this first automatic digital calcuator was conceived in the 1930s by Howard H. Aiken, then a graduate student from Harvard University with a Ph. D. in theoretical physics. The Mark I had a total of 78 adding machines linked together containing 765,000 parts; 3,300 electrical relays; over 500 miles of wire and more than 175,000 connections. The machine accepted input via punched cards, paper tape or through manually set switches to indicate the values to be processed. The output was generated by an electric typewriter or punched into additional cards. Multiple operations were programmed into the machine with perforated tape. Physically the machine performed calculations through a series of small gears, electro-mechanical counter wheels, and switches. The significant advancement from Hollerith's machine was the automatic feeding of paper encoded values and operations.

The successor to the Mark I, the Mark II, still used relays, but featured an electrical memory and a system of 'constant' values that were referenced during run-time.

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A necessary precursor to the first electronic computers was the invention of the switching vacuum tube, credited to Lee de Forest in 1906. The ability of vacuum tubes to act as switches (on/off devices that stop or start an electric current) would later be important in the building of the first electronic computers.

During World War II, the first electronic computers were developed by the British and U. S. governments as a result of secret military projects.

Konrad Zuse (1910-1995) is an under-credited but highly fruitful German computer designer. Working in relative isolation in pre-war Germany, Zuse built three prototype electronic computers which computed using the binary number system and other advanced design concepts. His third model, the Z3, was completed well before any of the computers shown below. However, Zuse was in a chaotic German wartime environment and lacked official support, and all three of the working models were destroyed during World War II. Despite being drafted into the German army, Zuse survived the war, built another computer in Switzerland, and later was the first designer to propose pipelining the computations of a computer processor. In 1949, Zuse formed Zuse KG, where he worked until 1966. Zuse KG grew into a leading manufacturer of small scientific computers, employing a thousand people.

Dr. John V. Atanasoff and graduate student Clifford Berry, of Iowa State University, worked on a prototype electronic computer between 1937 and 1942 . Their work introduced key design ideas which may have been communicated from Atanasoff to Mauchly, who later may have incorporated them into the design of the better-known ENIAC computer. Some people give Atanasoff credit for creating the very first working electronic computer, although most historic attention has focused on the ENIAC as being the first.

The highly secret, military Colossus project produced a series of about ten electronic computers used by British codebreakers to read encrypted German messages during World War II. The Colossus computers used the binary number system for computation. The Colossus prototype was initially completed by engineer Tommy Flowers in 1943 at the Post Office Research Station, Dollis Hill, with input from mathematician Max Newman and a few others. The project moved to Bletchley Park by 1944 and lasted until the end of the war.

John Mauchly and J. Presper Eckert of the University of Pennsylvania proposed the ENIAC (Electrical Numerical Integrator And Computer) to the U.S. Army Ordnance Department's Ballistics Research Laboratory in 1943, and then served as its main designers until construction was finished in 1946. It was a military project justified by a need to compute ballistic trajectories, and was one of the earliest general-purpose, programmable electronic computers.

ENIAC performed its computations using the decimal number system, instead of the binary number system used by most subsequent digital computers. Also, ENIAC was not yet able to store its own program in memory. It had to be programmed by setting switches on function tables and by changing the wiring; considerable human effort was required to reprogram it.

The designers of ENIAC jointly formed the Eckert-Mauchly Computer Corporation in 1946, which was bought by Remington Rand in 1950. In 1951, this company delivered the first U. S. commercial computer, called the UNIVAC, to the United States Census Bureau. It was a stored-program computer, like its non-commercial sister the EDVAC. Competing fiercely with IBM, the company eventually built 46 of the earliest commercial computer systems.

The EDVAC ((Electronic Discrete Variable Automatic Computer) was a successor to ENIAC, intended to resolve some design difficulties. It was the first internally stored program computer to be built, a major improvement over the ENIAC. The U.S. Army Ballistics Research Laboratory funded the development of EDVAC, and it was built at the Aberdeen Proving Ground by the University of Pennsylvania, including ENIAC designers Eckert & Mauchly. They were joined on the EDVAC design by John von Neumann and some others.

The EDVAC realized the stored-program concept first published in von Neumann's 1945 report First Draft of a Report on the EDVAC.

Although its design predates the UNIVAC, the EDVAC did not become fully operational until 1952.

Famous people in history of computing

For now, see this list of people who made conceptual breakthroughs in computer science.

Famous concepts in history of computing

For now, see this list of seminal concepts in computer science.

External links

• The Computer History Museum
• Charles Babbage Institute: Center for History of Information Technology at the University of Minnesota