4355 entries. 93 themes. Last updated March 26, 2015.

Computer & Calculator Design / Architecture Timeline


300 BCE – 30 CE

The Earliest Surviving Analog Computer: the Antikythera Mechanism Circa 150 BCE – 100 BCE

The Antikythera Mechanism discovered off the island of Antikythera, Greece in 1900 or 1901, includes the only specimen preserved from antiquity of a scientifically graduated instrument. It may also be considered the earliest extant mechanical calculator. The device is displayed at the National Archaeological Museum of Athens, accompanied by a reconstruction made and donated to the museum by physicist and historian of science Derek de Solla Price.

"The Antikythera mechanism must therefore be an arithmetical counterpart of the much more familiar geometrical models of the solar system which were known to Plato and Archimedes and evolved into the orrery and the planetarium. The mechanism is like a great astronomical clock without an escapement, or like a modern analogue computer which uses mechanical parts to save tedious calculation . . . . It is certainly very similar to the great astronomical cathedral clocks that were built. . . ." in Europe beginning in the fourteenth century.

Applying high-resolution imaging systems and three-dimensional X-ray tomography, in 2008 experts deciphered inscriptions and reconstructed functions of the bronze gears on the mechanism. The results of this research, revealed details of dials on the instrument’s back side, including the names of all 12 months of an ancient calendar. Scientists found that the device not only predicted solar eclipses but also organized the calendar in the four-year cycles of the Olympiad, forerunner of the modern Olympic Games.

The new findings also suggested that the mechanism’s concept originated in the colonies of Corinth, possibly Syracuse, in Sicily. The scientists said this implied a likely connection with Archimedes, who lived in Syracuse and died in 212 BCE. It is known that Archimedes invented a planetarium which calculated motions of the moon and the known planets. It is also believed that Archimedes wrote a manuscript, which did not survive, on astronomical mechanisms. Some evidence had previously linked the complex device of gears and dials to the island of Rhodes and the astronomer Hipparchos, who had made a study of irregularities in the Moon’s orbital course.

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1200 – 1300

al-Jazari's Clocks: Perhaps the Earliest Programmable Analog Computer 1206

A depiction of the Castle Water Clock from al-Jazari's 'Book of Knowledge of Ingenious Mechanical Devices.' This manuscript is preserved at the Museum of Fine Arts in Boston. (View Larger)

In the al-Jāmiʿ bain al-ʿilm wa al-ʿamal al-nāfiʿ fī ṣināʿat al-ḥiyal (The Book of Knowledge of Ingenious Mechanical Devices) written in 1206, the year of his death, Muslim polymath, engineer and inventor Badi'al-Zaman Abū al-'Izz ibn Ismā'īl ibn al-Razāz al-Jazarī (بديع الزمان أَبُو اَلْعِزِ بْنُ إسْماعِيلِ بْنُ الرِّزاز الجزري‎, Turkish: Ebû’l İz İbni İsmail İbni Rezzaz El Cezerî) from Jazirat ibn Umar (current Cizre,Turkey), described 100 mechanical devices, about 80 of which were trick vessels of various kinds, along with instructions on how to construct them. These included his elephant clock, scribe clock, and castle clock. The castle clock, a most sophisticated water-powered astronomical clock, has been called the earliest programmable analog computer. 

"It was a complex device that was about 11 feet high, and had multiple functions alongside timekeeping. It included a display of the zodiac and the solar and lunar orbits, and a pointer in the shape of the crescent moon which travelled across the top of a gateway, moved by a hidden cart and causing automatic doors to open, each revealing a mannequin, every hour. It was possible to re-program the length of day and night everyday in order to account for the changing lengths of day and night throughout the year, and it also featured five robotic musicians who automatically play[ed] music when moved by levers operated by a hidden camshaft attached to a water wheel. Other components of the castle clock included a main reservoir with a float, a float chamber and flow regulator, plate and valve trough, two pulleys, crescent disc displaying the zodiac, and two falcon automata dropping balls into vases" (Wikipedia article on Al-Jazari, accessed 04-02-2009).

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1600 – 1650

The Japanese Adopt the Abacus, Calling it the Soroban Circa 1600

Japanese soroban abacus 1x5 from Meiji period (1868-1912).

Diagram of Soroban.

About the year 1600 the Japanese adopted the Chinese 1/5 abacus via Korea. In Japanese the abacus is called soroban.

The 1/4 abacus appeared in Japan about 1630.

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John Napier Invents Logarithms, Napier's Bones & the Lightning Calculating Device 1614 – 1617

Preface page from Mirifici logarithmorum canonis descriptio, by John Napier, describing the (then) new mathematical device known as logarithms.



In 1614 Scottish mathematician, physicist, astronomer & astrologer, and also the 8th Laird of Merchistoun John Napier published from Edinburgh his Mirifici logarithmorum canonis descriptio (The Description of the Wonderful Canon of Logarithms), announcing his invention of logarithms,with the goal of increasing calculating speed and reducing drudgery.

Three years later, in 1617, Napier published Rabdologiae, describing two calculating devices: “Napier’s bones,” and the Multiplicationis promptuarium, or the lightning calculator.

"He [Napier] wrote that the multiplication and division of great numbers is troublesome, involving tedious expenditure of time, and subject to "slippery errors." His tables reduced these difficulties to simple addition and subtraction, and won immediate recognition. A set of Napier’s bones are usually made of boxwood or ivory and often contained in a box or case that would fit in a pocket. A set usually contains 10 rods, plus extras representing squares and cubes.  

"Use. Addition is accomplished by reading the appropriate bones along the diagonal. To obtain a product of 224 x 44, the rods 2, 2, and 4 are put alongside each other, and the result is read off by combining the numbers in the fourth row -- 0/8, 0/8, 1/6 -- for the correct answer 896. This is repeated and the two products added together to give 9856. The bones are sometimes associated with an abacus to provide a store in the multiplication process" (Gordon Bell's website, accessed 10-12-2011).

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William Oughtred Invents the Circular Form of Slide Rule 1632

English priest and mathematician William Oughtred invented the circular form of slide rule. He published Circles of Proportion and the Horizontal Instrument in London in 1632 describing slide rules and sundials.

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Blaise Pascal Invents a Calculator: The Pascaline 1642

Mathematician and philosopher Blaise Pascal invented an adding machine, the Pascaline.

"Use. The dials show the French monetary unit, the livre, which was divided into 12 deniers, each subdivided into 20 sols. The essential part of the machine was its decimal carry; each toothed wheel moved forward one unit (one-tenth of a revolution on each wheel except those of deniers and sols) when the previous wheel had completed one revolution. Subtraction was based on complementary numbers that could be revealed by moving the strip at the top of the calculator" (Gordon Bell's website, accessed 10-12-2011).

In 1645 Pascal published an eighteen-page pamphlet describing his calculating machine. It was called Lettre dédicatoire à Monseigneur le Chancelier sur le sujet de la machine nouvellement inventée par le Sieur B. P. pour faire toutes sortes d’opérations d’arithmétique, par un mouvement reglé, sans plume ny jettons avec un advis necessaire à ceux qui auront curiosité de voir ladite machine. . . . The pamphlet does not identify a place of printing or a printer’s name, so we may assume that Pascal paid for its printing. When we published Origins of Cyberspace OCLC cited only two copies of this pamphlet in one French library and no copies in North America.

Pascal's pamphlet was reprinted along with additional material related to the Pascaline in his Oeuvres (1779), vol. 4, 7-30. The additional material consisted of Pascal's 1650 letter describing the machine that he presented to Queen Christina of Sweden; the privilege for its construction and sale issued in 1649, and Denis Diderot's description of the machine published in the Encyclopédie.

Hook & Norman, Origins of Cyberspace (2002) no. 13.

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1650 – 1700

Description of the "Mathematical Organ" 1668

In 1668 Organum Mathematicum  by the German Jesuit scientist Gaspard Schott was posthumously published in Nuremberg. In this book Schott described his “mathematical organ,” and his calculating machine based on Napier’s rods.

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More Affordable and Easier to Use than the Pascaline 1671

Pierre Petit's Arithmetic Cylinder.

Pascal's Pascaline calculator.

In Dissertations academiques. . . avec un discours sur. . . un cylindre arithmetique published in Paris in 1671, Pierre Petit described an arithmetic cylinder, which he said was more affordable and easier to use than Pascal’s Pascaline.

John Napier (1550-1617) invented several mechanical methods to simplify and speed up the arithmetic calculations, especially multiplication.  His most famous invention was his Napier Rods, later known as Napier’s Bones.  Pierre Petit improved on Napier’s Bones by devising an arithmetic cylinder using long bands of paper strips with all of the multiples of John Napier’s rabdology.  The long bands were then attached end to end and mounted on a wooden cylinder the size of a child's drum or a hat. The reckoning principles were identical to Napier's bones.

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The First Book on a Calculating Machine Published in English 1673

Title page of Samuel Morland's The Discription and Use of Two Arithmetick Instruments.

Samuel Morland.

The adding device of Samuel Moreland, made by Humphry Adamson.

Morland's multiplication machine, based on the principle of Napier's bones.

In 1673 English diplomat, mathematician and inventor Samuel Morland published in London The Description and Use of Two Arithmetic Instruments. This was the first monograph on a calculating machine published in English, and after Galileo's Compasso, and Napier's Rabdologiae, the first book a calculator in any language, apart from Pascal's 18-page pamphlet on the Pascaline.

After entering government service in 1653 Morland was chosen to accompany a British diplomatic mission to the court of Sweden's Queen Christina. The Swedish Queen was a noted patron of the sciences, and Blaise Pascal had presented her with one of his Pascaline calculators in 1652. It is likely that Morland had the opportunity to familiarize himself with the Pascaline while in Sweden.  

During the 1660s Morland devised  three calculating machines—one for trigonometry (1663), one for addition and subtraction (1666) and one for multiplication and division (1662). In his book Morland described two calculating devices, which worked "without charging the memory, disturbing the mind, or exposing the operations to any uncertainty." Morland's device is regarded by some as the first multiplying calculator.

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Leibniz Invents the Stepped Drum Gear Calculator 1673 – 1710

In 1673 German mathematician and philosopher Gottfried Wilhelm Leibniz made a drawing of his calculating machine mechanism. Using a stepped drum, the Leibniz Stepped Reckoner, mechanized multiplication as well as addition by performing repetitive additions. The stepped-drum gear, or Leibniz wheel, was the only workable solution to certain calculating machine problems until about 1875. The technology remained in use through the early 1970s in the Curta hand-held calculator.

Leibniz first published a brief illustrated description of his machine in "Brevis descriptio machinae arithmeticae, cum figura. . . ," Miscellanea Berolensia ad incrementum scientiarum (1710) 317-19, figure 73. The lower portion of the frontispiece of the journal volume also shows a a tiny model of Leibniz's calculator. Because Leibniz had only a wooden model and two working metal examples of the machine made, one of which was lost, his invention of the stepped reckoner was primarily known through the 1710 paper and other publications. Nevertheless, the machine became well-enough known to have great influence. 

Leibniz conceived the idea of a calculating machine in the early 1670s with the aim of improving upon Blaise Pascal's calculator, the Pascaline. He concentrated on expanding Pascal's mechanism so it could multiply and divide. The first recorded indirect reference is in a letter from the French mathematician Pierre de Carcavi (Carcavy) dated June 20, 1671 in which Pascal's machine is referred to as "la machine du temps passé." Leibniz demonstrated a wooden model of his calculator at the Royal Society of London on February 1, 1673, though the machine could not yet perform multiplication and division automatically. In a letter of March 26, 1673 to Johann Friedrich, where he mentioned the presentation in London, Leibniz described the purpose of the "arithmetic machine" as making calculations "leicht, geschwind, gewiß" [sic], i.e. easy, fast, and reliable. Leibniz also added that theoretically the numbers calculated might be as large as desired, if the size of the machine was adjusted; quote: "eine zahl von einer ganzen Reihe Ziphern, sie sey so lang sie wolle (nach proportion der größe der Maschine)" ("a number consisting of a series of figures, as long as it may be in proportion to the size of the machine").

On July 14, 1674, Leibniz informed Heinrich (Henry) Oldenburg, secretary of the Royal Society, that a new model had "at last been successfully completed" and was able to "produce a multiplication by making a few turns of a particular wheel, without any effort." The letter also refers to his good fortune in being able to entrust the work to the Parisian craftsman and clockmaker Olivier (or Ollivier: his first name does not seem to be known), ‘a man who preferred fame to fortune’ (quoted in M.R. Antognazzi. Leibniz: an intellectual biography [2009]). Leibniz showed off an improved version of the calculating machine at the Académie royale des sciences in Paris on January 9, 1675, and on his final departure from Paris on October 4, 1676 took a further improved model to show Oldenburg in London.

After Leibniz’s departure, work on the calculating machine continued under the supervision of his Danish friend Friedrich Adolf Hansen (1652-1711), and Leibniz continued to correspond with Olivier. The Leibniz archive includes three letters from Olivier, dated March 24 and July 29, 1677 and  November 15, 1678; indeed Leibniz seems to have had some effort made to have Olivier called to Hanover to continue his work. After about 1678 work on the machine seems to have lapsed until Leibniz began to develop a new prototype in the early 1690s. At some point Leibniz's wooden model and his first metal machine were lost. The second machine, which was built from 1690 to 1720, is preserved in the Niedersächsische Landesbibliothek, Hanover. 

On May 21, 2014 Christie's in London auctioned Leibniz's autograph draft contract between Leibniz's friend Adolf Hansen, acting on Leibniz's behalf and the clockmaker Olivier in Paris, for the construction of Leibniz's calculating machine. The 3.5 page contract written by Leibniz in French consisted of 20 numbered articles with some details of payments left blank. The contract was undated but Christie's assigned to it the date of circa 1677. The manuscript came "from the collection of the French Leibniz scholar Lous-Alexandre Foucher de Careil (1826-1891) -- by descent – private collection."

From Christie's catalogue description I quote:

"‘Le dit sieur Leibniz m’ayant informé partie par écrit, et partie de vive voix et par quelques modelles, d’une machine Arithmetique de son invention; en sorte que je n’y ay trouvé aucune difficulté, je me suis engagé à l’executer de la manière suivante …’

"The contract comprises 20 meticulously detailed clauses, describing in detail the machine and the financial and practical arrangements for its construction: it is to produce numbers up to three figures; it is to be capable of multiplication and division, as well as addition and subtraction, with the mechanism (consisting of a system of fixed and mobile pieces, and equal and unequal cogs) described in detail, first for multiplication and division, then for addition and subtraction, noting that the operations should be effected immediately ‘et non pas comme dans la machine du temps passé après un delay ou intervalle’; the machine is to be perfectly finished, made of iron or steel, and enclosed in ‘une petite boëtte propre, à fin qu’il ne paroisse que ce qu’il faut pour l’opération’; the operation of the machine is then specified. The contract goes on to note that Olivier had previously agreed to construct such a machine in one or two months for a payment of ‘cent écus blancs ou trois cens francs’, part of which has been advanced, but that he had failed (in part because of illness) to give satisfaction; he now engages to complete the work in three months, with his goods as surety; and he is to show the progress of his work to Hansen, and inform Leibniz by letter, each week. 

"‘La machine doit avoir deux pieces aussi longues qu’elle, dont l’une est immobile et sert de base à tout, l’autre est mobile, et glisse dans la première, à fin d’aller de chiffre en chiffre lors qu’on change les multiplicateurs ou les quotiens de la division …

"La piece mobile porterà ce qui sert pour le nombre qui doit estre multiplié et pour le nombre qui doit estre divisé: au lieu que la precedente servoit pour le produit, pour le multipliant, et pour le quotient cellecy portera donc les roues à dens inégales, et ce qui sert à les ajuster, et à les mettre sur un nombre donné, afin que tantost 9, tantost 8, tantost 7 dens inegales rencontrent la roue de la partie immobile qui y repond …’ "

Christie's estimated the contract at £200,000-£300,000; however, the manuscript did not sell in the auction.

(This entry was last revised on 07-26-2014.)

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Leibniz on Binary Arithmetic March 15, 1679 – 1705

A manuscript dated March 15, 1679 by Gottfried Wilhelm Leibniz, preserved in the Gottfried Wilhelm Leibniz, Bibliothek Niedersächsische Landesbibliothek, Hannover, “includes a brief discussion of the possibility of designing a mechanical binary calculator which would use moving balls to represent binary digits.”

Though Leibniz thought of the application of binary arithmetic to computing in 1679, the machine he outlined was never built, and he published nothing on the subject until his Explication de l'arithmétique binaire, qui se sert des seuls caracteres 0 & 1; avec des remarques sur son utilité, & sur ce qu'elle donne le sens des anciens figues Chinoises de Fohy' published in Histoire de l'Académie Royale des Sciences année MDCCIII. Avec les mémoires de mathématiques, which appeared in print in 1705.

"The publication of the Explication was prompted by Leibniz's correspondence with Joachim Bouvet, a member of the Jesuit Mission in China. Leibniz had developed an interest in China, and in April 1697 he edited a collection of letters and essays by members of the Mission, entitled Novissima Sinica. A copy of this came into the hands of Bouvet, who wrote to Leibniz on 18 October 1697 expressing his commendation of the work. Thus began an extended correspondence between the two men which proved to be very important for the dissemination of Leibniz's ideas about binary arithmetic. The crucial exchange began on 15 February 1701, when Leibniz wrote to Bouvet describing for his correspondent the principles of his binary arithmetic, including the analogy of the formation of all the numbers from 0 and 1 with the creation of the world by God out of nothing. Bouvet immediately recognised the relationship between the hexagrams of the I ching and the binary numbers and he communicated his discovery in a letter written in Peking on 4 November 1701. This reached Leibniz, after a detour through England, on 1 April 1703. With this letter, Bouvet enclosed a woodcut of the arrangement of the hexagrams attributed to Fu-Hsi, the mythical founder of Chinese culture, which holds the key to the identification. Within a week of receiving Bouvet's letter, Leibniz had sent to Abbé Bignon for publication in the Mémoires of the Paris Academy his Explication de l'Arithmétique binaire,... & sue ce qu'elle donne le sens des anciens figures Chinoises de Fohy. Ten days later he sent a brief account to Hans Sloane, the Secretary of the Royal Society. Leibniz viewed binary arithmetic less as a computational tool than as a means of discovering mathematical, philosophical and even theological truths. He remarked to Tschirnhaus in 1682 that he anticipated from the use of binary numbers discoveries in number theory that other progressions could not reveal. It was at the same time a candidate for the characteristica generalis, his long sought-for alphabet of human thought. With base 2 numeration Leibniz witnessed a confluence of several intellectual strands in his world view, including theological and mystical ideas of order, harmony and creation. Fontanelle, secretary of the Paris Academy, wrote the unsigned review of Liebniz's paper for the Mémoires section of the volume. He noted that arithmetic could have different bases besides ten; bases such as 12, and two as in the case of Leibniz's binary system. He also noted that although the binary system was not practical for common use Leibniz thought that it would be of advantage in advanced mathematics" (W.P. Watson, antiquarian book description, accessed from ilabdatabase.com on 01-21-2010). 

This manuscript was first published in 1966 to commemorate the 250th anniversary of Leibniz's death as Herrn von Leibniz' Rechnung mit Null und Eins. That book included facsimiles of Leibniz's "Explication de l'arithmétique binaire" (1705), his two letters to Johann Christian Schulenberg on binary arithmetic (March 29 and May 17, 1698), published in the Opera Omnia of 1768, and historical articles and German translations.

(This entry was last revised on 07-26-2014.)

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1750 – 1800

de Prony Produces Mathematical Tables Calculated by Hairdressers Unemployed after the French Revolution 1793 – 1801

French mathematician and engineer Gaspard Clair François Marie Riche de Prony, Engineer-in-Chief of the École Nationale des Ponts et Chaussées, undertook, beginning in 1793, the production of logarithmic and trigonometric tables for the French Cadastre. He was asked to produce the tables by the French National Assembly, which, after the French Revolution, wanted to bring uniformity to the multiple measurements and standards used throughout the nation. The tables and their production were vast, with values calculated to between fourteen and twenty-nine decimal places.

Inspired by Adam Smith's Wealth of Nations, de Prony produced the tables through the systematic division of labor, bragging that he could manufacture logarithms as easily as one could manufacture pins. At the top of the organizational hierarchy were scientists and mathematicians who devised the formulas. Next were workers who created the instructions for doing the calculations. At the bottom were about ninety human computers who were not trained in mathematics, but who followed instructions very carefully. De Prony found that hairdressers unemployed after the French Revolution, who were meticulous by nature, made excellent human computers. In spite of the division of labor it took eight years for the tables to be completed, and because of the inflation during the French Revolution the tables were never published in full. Portions were published for the first time in 1891.    

Though the tables remained unpublished the manuscripts could be examined and consulted. De Prony's method of production of the tables inspired Charles Babbage in the design of his Difference Engine No. 1 in 1822.

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1800 – 1850

Joseph-Marie Jacquard's Loom Uses Punched Cards to Store Patterns 1803 – 1806

In 1803 Joseph-Marie Jacquard of Lyon received a patent for the automatic loom, which he invented in 1801. Jacquard's loom used punched cards to store patterns, and reduced strenuous manual labor.

In 1806 Jacquard's loom was declared public property, and Jacquard received a pension. However, he was forced to flee from Lyon because of the anger of the weavers, who feared they would lose their jobs to the new technology. Jacquard persevered, and by the time of his death there were thirty thousand Jacquard looms installed in Lyon alone.

The Jacquard loom did no computation, and was not a digital device. However, it is considered an important conceptual step in the history of computing because the Jacquard method of storing information in punched cards, and weaving a pattern by following the series of instructions recorded in a train of punched cards, was used by Charles Babbage in his plans for data and program input, and data output and storage in his general purpose programmable computer, the Analytical Engine. Trains of Jacquard cards were programs in the modern sense of computer programs, though the word "program" did not have that meaning until after the development of electronic computers after World War II.

Precursors of Jacquard

In 1725 Basile Bouchon of Lyon, the son of an organ maker, adapted the concept of musical automata controlled by pegged cylinders to the repetitive task of weaving. He invented a loom that was controlled by perforated paper tape.

In order to make the input of instructions to the loom more flexible in 1728 Jean-Baptiste Falcon substituted a chain of punched paper cards for the perforated paper tape employed by his colleague Basile Bouchon.

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The Thomas Arithmometer, the First Commercially Produced Mechanical Calculator 1820

Charles Xavier Thomas' Arithometer.

Charles Xavier Thomas

In 1820 Charles Xavier Thomas of Alsace, an entrepreneur in the insurance industry, invented the arithmometer, the first commercially produced adding machine, presumably to speed up and make more accurate, the enormous amount of daily computation insurance companies required. Remarkably, according to the Wikipedia, Thomas received almost immediate acknowledgement for this invention, as he was made Chevalier of the Legion of Honor only one year later, in 1821.  At this time he changed his name to Charles Xavier Thomas, de Colmar, later abbreviated to Thomas de Colmar.

"Initially Thomas spent all of his time and energy on his insurance business, therefore there is a hiatus of more than thirty years in between the first model of the Arithmometer introduced in 1820 and its true commercialization in 1852. By the time of his death in 1870, his manufacturing facility had built around 1,000 Arithmometers, making it the first mass produced mechanical calculator in the world, and at the time, the only mechanical calculator reliable and dependable enough to be used in places like government agencies, banks, insurance companies and observatories just to name a few. The manufacturing of the Arithmometer went on for another 40 years until around 1914" (Wikipedia article on Charles Xavier Thomas, accessed 10-10-2011).

The success of the Arithmometer, which to a certain extent paralleled Thomas's success in the insurance industry, was, of course, in complete contrast to the problems that Charles Babbage faced with producing and gaining any acceptance for his vastly more sophisticated, complex, ambitious and expensive calculating engines during roughly the same time frame. Thomas, of course, produced an affordable product that succeeded in speeding up basic arithmetical operations essential to the insurance industry while Babbage's scientific and engineering goals initially of making mathematical tables more accurate, and later, of automating mathematical operations in general, did not attempt to meet a recognized industrial demand. 

"The [Arithmometer] mechanism has three parts, concerned with setting, counting, and recording respectively. Any number up to 999,999 may be set by moving the pointers to the numbers 0 to 9 engraved next to the six slots on the fixed cover plate. The movement of any of these pointers slides a small pinion with ten teeth along a square axle, underneath and to the left of which is a Leibniz stepped wheel.  

"The Leibniz wheel, a cylinder having nine teeth of increasing length, is driven from the main shaft by means of a bevel wheel, and the small pinion is thus rotated by as many teeth as the cylinder bears in the plane corresponding to the digit set. This amount of rotation is transferred through one of a pair of bevel wheels, carried on a sleeve on the same axis, to the ‘results’ figure wheel on the back row on the hinged plate. This plate also carried the figure wheel recording the number of turns of the driving crank for each position of the hinged plate. The pair of bevel wheels is placed in proper gear by setting a lever at the top left-hand cover to either "Addition and Multiplication" or "Subtraction and Division." The ‘results’ figure wheel is thereby rotated anti-clockwise or clockwise respectively.  

"Use. Multiplying 2432 by 598 may be performed as follows: Lift the hinged plate, turn and release the two milled knobs to bring all the figure wheels to show zero; lower the hinged plate in its position to the extreme left; set the number 2432 on the four slots on the fixed plate; set the lever on the left to "multiplication" and turn the handle eight times; lift the hinged plate, slide it one step to the right, and lower it into position; turn the handle nine times; step the plate one point to the right again and the turn the handle five times. The product 1,454,336 will then appear on the top row, and the multiplier 598 on the next row of figures" (From Gordon Bell's website, accessed 10-12-2011).

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Babbage Begins Construction of his Difference Engine No. 1 1822

About 1820 mathematician Charles Babbage started building a model of his first Difference Engine, a special-purpose machine that linked adding and subtracting mechanisms to one another to calculate the values of more complex mathematical functions. Frustrated by “the intolerable labour and fatiguing monotony of a continued repetition of similar arithmetical calculations”, came up with the plan of designing a machine capable of performing various mathematical functions. The immediate purpose of the machine was to improve the accuracy of printed mathematical tables—especially the Nautical Almanac— which were the most widely used calculating devices of the time.

By 1822 Babbage had constructed a model of his Difference Engine No. 1, a special-purpose calculating machine far more complex than any that had previously been conceived, designed to compute mathematical tables by the method of finite differences and to print the results. In the design of his machine Babbage was influenced by the division of labor employed in the celebrated manuscript tables of de Prony, which Babbage had seen in 1819. The division of labor, both physical and mental, became central themes of Babbage’s economic thought later developed in his Economy of Machinery and Manufactures.

Babbage was convinced of the “great utility” of his machine, but knew that constructing a larger version would entail “very considerable expense,” and would also leave him no time to pursue his studies in pure mathematics. On July 3, 1822, as a means of testing the waters, Babbage wrote an open letter to Sir Humphry Davy, president of the Royal Society, in which he presented a detailed description of his Difference Engine. He had his letter published as a pamphlet, and sent it to people he deemed influential:

A Letter to Sir Humphry Davy, Bart. . . . on the Application of Machinery to the Purpose of Calculating and Printing Mathematical Tables (London, 1822).

This was Babbage's first public statement of his plans for his calculating engine, and his first publication on his project for developing calculating engines, on which he would devote most of his creative energy for the remainder of his life. A copy of the pamphlet reached the Lords of the Treasury, who referred it back to the Royal Society on April 1, 1823, with a letter requesting the Society’s opinion of Babbage’s machine. One month later, on May 1, the Royal Society responded to the Treasury as follows:

"That it appears to the Committee, that Mr. Babbage has displayed great talents and ingenuity in the construction of his machine for computation, which the Committee think fully adequate to the attainment of the objects proposed by the Inventor, and that they consider Mr. Babbage as highly deserving of public encouragement in the prosecution of his arduous undertaking" (Great Britain. Parliament. House of Commons. Sessional Papers [1823], p. 6).

This favorable report gained Babbage his first national funding of £1000 toward his construction of the Difference Engine. The project tested the limits of precision obtainable by machine tool makers at the time; it also ended up being far more costly than expected, claiming £17,000 of the government’s money over the next decade before foundering in 1833, largely due to contractual disputes between Babbage and Joseph Clement, the engineer hired to construct Babbage’s machine. By this time Babbage had begun to turn his attention to the Analytical Engine, a far more complex and powerful calculating machine whose design would occupy Babbage for most of the rest of his scientific career.

Remarkably the printing feature of Babbage's Difference Engine No. 1 became known to printers through Thomas Hansard's Typographia, an Historical Sketch of the Origin and Progress of the Art of Printing (1825). In January 2015 when I was reading what Hansard had to say about the highly advanced inventions typesetting and printing inventions of William Church, about which Hansard was incredulous, I came across these remarks of Hansard on p. 689-90:

"But surely this [Church's inventions], wonderful as it may seem, is far exceeded by the proposed application of machinery to the work of the head as well as of the hands?—See what follows!


"Charles Babbage, Esq. F.R.S., London and Edinburgh &c. in a letter addressed to sir Humphry Davy, president of the Royal Society of London, has announced to the world, that he has invented various machines, by which some of the most complicated processes of arithmetical calculation may be performed with certainty and dipatch; and in order to avoid the errors which might be produced in copying and printing the numbers in the common way, the ingenious inventor states, that he has contrived means by which the machines shall take, from several boxes containing type, the numbers which they calculate, and place them side by side; thus becoming at once a substitute for the computer [i.e. a human computer] and the compositor.

 "The scheme of Mr. Babbage is, however, much more within the scope of probability than that of Dr. Church. He does not go to the casting-type process— his authorship and composing go no further than the ten figures— and his object is, to effect accuracy where it is of great consequence, so that i may, perhaps be of general benefit."

Hook & Norman, Origins of Cyberspace (2002) No. 29. 

(This entry was last revised on 01-20-2015.)

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Babbage Describes the Logic and Operation of Machinery by Means of Notation 1826

In 1826 mathematician and engineer Charles Babbage published "On a Method of Expressing by Signs the Action of Machinery," Philosophical Transactions 111 (1826) 250-65, 4 plates. This was the first publication of Babbage's exposition of his system of mechanical notation that enabled him to describe the logic and operation of his machines on paper as they would be fabricated in metal. Babbage later stated that "Without the aid of this language I could not have invented the Analytical Engine; nor do I believe that any machinery of equal complexity can ever be contrived without the assistance of that or of some other equivalent language. The Difference Engine No. 2 . . . is entirely described by its aid" (Babbage, Passages from the Life of a Philosopher [1864], 104).  

Babbage considered his mechanical notation system to be one of his finest inventions, and thought it should be widely implemented. It was a source of frustration to him that no other machine designer adopted it (probably because no other engineer during Babbage's time attempted to build machines as logically and mechanically complex as Babbage's). More than one hundred years later, in the 1930s, when developments in logic were applied to switching systems in the earliest efforts to develop electromechanical calculators, Claude Shannon demonstrated that Boolean algebra could be applied to the same types of problems for which Babbage had designed his mechanical notation system.  

"While making designs for the Difference Engine, Babbage found great difficulty in ascertaining from ordinary drawings-plans and elevations-the state of rest or motion of individual parts as computation proceeded: that is to say in following in detail succeeding stages of a machine's action. This led him to develop a mechanical notation which provided a systematic method for labeling parts of a machine, classifying each part as fixed or moveable; a formal method for indicating the relative motions of the several parts which was easy to follow; and means for relating notations and drawings so that they might illustrate and explain each other. As the calculating engines developed the notation became a powerful but complex formal tool. Although its scope was much wider than logical systems, the mechanical notation was the most powerful formal method for describing switching systems until Boolean algebra was applied to the problem in the middle of the twentieth century. In its mature form the mechanical notation was to comprise three main components: a systematic method for preparing and labeling complex mechanical drawings; timing diagrams; and logic diagrams, which show the general flow of control" (Hyman, Charles Babbage [1982], 58).

Hook & Norman, Origins of Cyberspace (2001) no. 37.

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Babbage's "On the Economy of Machinery and Manufactures" Begins Operations Research 1832 – 1835

In 1832 Charles Babbage published On the Economy of Machinery and Manufactures, the first work on operations research, partially based on data he had accumulated during the previous ten years in order to build his Difference Engine No. 1. Primary themes of the book were the division of labor and the division of mental labor, to which Babbage devoted chapters 19 and 20. The first part of his chapter on the division of mental labor was an analysis of the methods used by de Prony in the production of his celebrated mathematical tables, and the third and fourth editions included in section 249 a small table calculated by the completed portion of the Difference Engine No. 1.  

Babbage had seen de Prony’s manuscript tables in 1819, and around 1820 began planning the Difference Engine No. 1 based on the principles of the division of labor. With this goal, Babbage visited factories throughout England, inspecting every machine and every industrial process. Rather than a study limited to engineering and manufacturing techniques, his book turned out to be an analysis of manufacturing processes within their economic context. Written when manufacturing was undergoing rapid development and radical change, the book represents an original contribution to British economics.

"Adam Smith had never really abandoned the belief, reasonable enough in his day, that agriculture was the principal source of Britain’s wealth; Ricardo’s ideas were focused on corn; Babbage for the first time authoritatively placed the factory in the centre of the stage. The book is at once a hymn to the machine, and analysis of the development of machine-based production in the factory, and a discussion of social relations in industry. . . .

"The Economy of Manufactures established Babbage’s position as a political economist and its influence is well attested, particularly on John Stuart Mill and Karl Marx. Babbage’s pioneering discussion of the effect of technical development on the size of industrial organizations was followed by Mill and the prediction of the continuing increase in the size of factories, often cited as one of Marx’s successful economic predictions, in fact derives from Babbage’s analysis. . . . Babbage wrote with many talents: a natural philosopher and mechanical engineer, his knowledge of factory and workshop practice was encyclopaedic; he was well-versed in relevant business practice; and he was without rival as a mathematician among contemporary British political economists" (Hyman, Charles Babbage, Pioneer of the Computer (1982) 103–4).

On the Economy of Machines and Manufactures was also the first book on operations research, discussing topics like the regulation of power, control of raw materials, division of labor, time studies, the advantage of size in manufacturing, inventory control, and duration and replacement of machinery. Besides regular pagination and chapters Babbage divided his book into numbered sections, which reached No. 467 by the third and fourth edition (1835), though the Table of Contents extended only to section No. 463. The book was indexed to the section numbers rather than to pages. 

In Chapter XI, "Of Copying", Babbage analyzed a surprisingly wide range of methods of duplication, including many different kinds of printing of different products, only a few categories of which were printing on paper. In section 159 he broke down the process of preparing the stereotype plates on which his book was printed into six different stages, and in Chapter XXI, "On the Cost of Each Separate Process in a Manufacture", section 256 he presented an exceptionally detailed accounting of all the costs in the production of the 3000 copies of the first edition of his book, which presumably he paid, followed by analyses of these costs in sections 257-262, the costs not including the extra charges for the small number of large paper copies (222 x 142mm) which Babbage ordered for presentation to his friends. Among the details mentioned in section 256 was that the book was printed on large sheets with 16 pages up, resulting in gatherings of 32 pages. As the book was printed from stereotype plates we may thus assume that the book was also printed by machine rather than by handpress, especially as its publisher Charles Knight was an early exponent of machine printing and its cost efficiencies. Though Babbage does not discuss the gold-stamped cloth bindings in which most of edition appeared, these were very early gold-stamped cloth edition bindings.

The work was Babbage’s most complete and professional piece of writing, and the only one of his books that went through four editions during his lifetime. The work was  translated into French and German, and appeared in an American edition also in 1832. Hook & Norman, Origins of Cyberspace (2002) No. 42.

(This entry was last revised on 03-01-2015.)

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Korsakov is Probably the First to Use Punched Cards for Information Processing and Storage September 1832

While working in the statistics department of the Police Ministry, Semen Nikolaevich Korsakov (Russian: Семён Николаевич Корсаков; Semyon Nikolayevich Korsakov), a Russian government official and inventor, developed several "machines for the comparison of ideas" to "enhance natural intelligence."  In the design of his machines Korsakov appears to have been the earliest to use punched cards for information processing and storage.

Korsakov's machines "included the 'linear homeoscope with movable parts', the 'linear homeoscope without movable parts', the 'flat homeoscope', the 'ideoscope', and the 'simple comparator'. The purpose of the devices was primarily to facilitate the search for information, stored in the form of punched cards or similar media (for example, wooden boards with perforations). Korsakov announced his new method in September 1832, and rather than seeking patents offered the machines for public use.

"The punch card had been introduced in 1805, but until that time had been used solely in the textile industry to control looms. Korsakov was reputedly the first to use the cards for information storage.

"Korsakov presented his ideas to the Imperial Academy of Sciences in St. Petersburg, but their experts rejected his application, failing to see the potential of mechanizing searches through large stores of information. His machines were largely forgotten until after the Second World War, when a revival of historical interest resulted in the publication (in 1961) of several documents from the Academy's archives relating to Korsakov's machines and the uncovering of a book about them written by Korsakov himself" (Wikipedia article on Semen Korsakov, accessed 10-07-2010).

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Coriolis Solves Differential Equations Using a Mechanical Device 1836

In Note sur un moyen de tracer des courbes données par des équations différentielles published in 1836 French mathematician, mechanical engineer and scientist Gaspard-Gustave Coriolis described a mechanical device to integrate differential equations of the first order. This was the beginning of researches on solution of differential equations using mechanical devices.

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The Most Famous Image in the Early History of Computing 1839

Portrait of Jacquard woven in silk on a Jacquard loom.

In 1839 weaver Michel-Marie Carquillat, working for the firm of Didier, Petit et Cie, in Lyon, France wove in fine silk a Portrait of Joseph-Marie Jacquard, The image, including caption and Carquillat’s name, taking credit for the weaving, measures 55 x 34 cm.; the full piece of silk including blank margins measures 85 x 66 cm.

This image, of which only about 10 examples are known, was woven on a Jacquard loom using 24,000 Jacquard cards, each of which had over 1000 hole positions. The process of mis en carte, or converting the image details to punched cards for the Jacquard mechanism, for this exceptionally large and detailed image, would have taken several workers many months, as the woven image convincingly portrays superfine elements such as a translucent curtain over glass window panes.

Once all the “programming” was completed, the process of weaving the image with its 24,000 punched cards would have taken more than eight hours, assuming that the weaver was working at the usual Jacquard loom speed of about forty-eight picks per minute, or about 2800 per hour. More than once this woven image was mistaken for an engraved image. The image was produced only to order, most likely in an exceptionally small number of examples. In 2012 the only recorded examples were those in the Metropolitan Museum of Art, the Science Museum, London, The Art Institute of Chicago, and the Computer History Museum, Mountain View, California. The image was the subject of the book by James Essinger entitled, Jacquard's Web. How a Hand Loom led to the Birth of the Information Age (2004).

To Charles Babbage the incredible sophistication of the information processing involved in the mis en carte — what we call programming— of this exceptionally elaborate and beautiful image confirmed the potential of using punched cards for the input, programming, output and storage of information in his design and conception of the first general-purpose programmable computer—the Analytical Engine. The highly aesthetic result also confirmed to Babbage that machines were capable of amazingly complex and subtle processes—processes which might eventually emulate the subtlety of the human mind.

“In June 1836 Babbage opted for punched cards to control the machine [the Analytical Engine]. The principle was openly borrowed from the Jacquard loom, which used a string of punched cards to automatically control the pattern of a weave. In the loom, rods were linked to wire hooks, each of which could lift one of the longitudinal threads strung between the frame. The rods were gathered in a rectangular bundle, and the cards were pressed one at a time against the rod ends. If a hole coincided with a rod, the rod passed through the card and no action was taken. If no hole was present then the card pressed back the rod to activate a hook which lifted the associated thread, allowing the shuttle which carried the cross-thread to pass underneath. The cards were strung together with wire, ribbon or tape hinges, and fan-folded into large stacks to form long sequences. The looms were often massive and the loom operator sat inside the frame, sequencing through the cards one at a time by means of a foot pedal or hand lever. The arrangement of holes on the cards determined the pattern of the weave.

“As well as patterned textiles for ordinary use, the technique was used to produce elaborate and complex images as exhibition pieces. One well-known piece was a shaded portrait of Jacquard seated at table with a small model of his loom. The portrait was woven in fine silk by a firm in Lyon using a Jacquard punched-card loom. . . . Babbage was much taken with the portrait, which is so fine that it is difficult to tell with the naked eye that it is woven rather than engraved. He hung his own copy of the prized portrait in his drawing room and used it to explain his use of the punched cards in his Engine. The delicate shading, crafted shadows and fine resolution of the Jacquard portrait challenged existing notions that machines were incapable of subtlety. Gradations of shading were surely a matter of artistic taste rather than the province of machinery, and the portrait blurred the clear lines between industrial production and the arts. Just as the completed section of the Difference Engine played its role in reconciling science and religion through Babbage’s theory of miracles, the portrait played its part in inviting acceptance for the products of industry in a culture in which aesthetics was regarded as the rightful domain of manual craft and art” (Swade, The Cogwheel Brain. Charles Babbage and the Quest to Build the First Computer [2000] 107-8).

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Luigi Menabrea Publishes the First Computer Programs, Designed for Babbage's Analytical Engine. Ada Lovelace Translates them Into English 1840 – 1843

In 1842 Italian mathematician and politician Luigi Federico Menabrea published "Notions sur la machine analytique de M. Charles Babbage" in Bibliothèque universelle de Genève, nouvelle série 41 (1842) 352–76. This was the first published account of Charles Babbage’s Analytical Engine and the first account of its logical design, including the first examples of computer programs ever published. As is well known, Babbage’s conception and design of his Analytical Engine—the first general purpose programmable digital computer—were so far ahead of the imagination of his mathematical and scientific colleagues that few expressed much curiosity regarding it. Babbage first conceived the Analytical Engine in 1834. This general-purpose mechanical machine— never completely constructed—embodied in its design most of the features of the general-purpose programmable digital computer. In its conception and design Babbage incorporated ideas and names from the textile industry, including data and program input, output, and storage on punched cards similar to those used in Jacquard looms, a central processing unit called the "mill," and memory called the "store."The only presentation that Babbage made concerning the design and operation of the Analytical Engine was to a group of Italian scientists.

In 1840 Babbage traveled to Torino (Turin) Italy to make a presentation on the Analytical Engine. Babbage’s talk, complete with charts, drawings, models, and mechanical notations, emphasized the Engine’s signal feature: its ability to guide its own operations—what we call conditional branching. In attendance at Babbage’s lecture was the young Italian mathematician Luigi Federico Menabrea (later prime minister of Italy), who prepared from his notes an account of the principles of the Analytical Engine. Reflecting a lack of urgency regarding radical innovation unimaginable to us today, Menabrea did not get around to publishing his paper until two years after Babbage made his presentation, and when he did so he published it in French in a Swiss journal. Shortly after Menabrea’s paper appeared Babbage was refused government funding for construction of the machine.

"In keeping with the more general nature and immaterial status of the Analytical Engine, Menabrea’s account dealt little with mechanical details. Instead he described the functional organization and mathematical operation of this more flexible and powerful invention. To illustrate its capabilities, he presented several charts or tables of the steps through which the machine would be directed to go in performing calculations and finding numerical solutions to algebraic equations. These steps were the instructions the engine’s operator would punch in coded form on cards to be fed into the machine; hence, the charts constituted the first computer programs [emphasis ours]. Menabrea’s charts were taken from those Babbage brought to Torino to illustrate his talks there"(Stein, Ada: A Life and Legacy, 92).

Menabrea’s 23-page paper was translated into English the following year by Lord Byron’s daughter, Augusta Ada King, Countess of Lovelace, daughter of Lord Byron, who, in collaboration with Babbage, added a series of lengthy notes enlarging on the intended design and operation of Babbage’s machine. Menabrea’s paper and Ada Lovelace’s translation represent the only detailed publications on the Analytical Engine before Babbage’s account in his autobiography (1864). Menabrea himself wrote only two other very brief articles about the Analytical Engine in 1855, primarily concerning his gratification that Countess Lovelace had translated his paper.

Hook & Norman, Origins of Cyberspace (2002) No. 60.

"Without being Worked out by Human Head & Hands. . . ."

While she was working on her translation, on July 10, 1843 Ada Lovelace composed a letter to Babbage concerning her notes to Menabrea's paper on programming Babbage's Analytical Engine. This autograph letter, preserved in the British Library (Add. MS 37192 folios 362v-363), includes the following text:

"I want to put in something about Bernouilli's Numbers, in one of my Notes, as an example of how an implicit function may be worked out by the engine, without  having been worked out by human head & hands first. Give me the necessary data and formulae."

The letter is notable for suggesting that Ada's knowledge of mathematics was limited, and that she may have mainly contributed poetic language to her annotations of the English translation of Menabrea's key paper, while incorporating mathematical examples written by Babbage. Because of Ada's fame as Byron's daughter, and her social position as the Countess of Lovelace, Babbage hoped that Ada's translation and annotation of Menabrea's paper would help promote building the Analytical Engine.

In October 1843, Ada Lovelace's "Sketch of the Analytical Engine Invented by Charles Babbage . . . with Notes by the Translator" was published in Scientific Memoirs, Selected from the Transactions of Foreign Academies of Science and Learned Societies 3 (1843): 666-731 plus 1 folding chart. At Babbage’s suggestion, Lady Lovelace added seven explanatory notes to her translation, which run about three times the length of the original. Her annotated translation has been called “” (Bromley, “Introduction” in Babbage, Henry Prevost, , xv). As Babbage never published a detailed description of the Analytical Engine, Ada’s translation of Menabrea’s paper, with its lengthy explanatory notes, represents the most complete contemporary account in English of this much-misunderstood machine.

At Babbage’s suggestion, Lady Lovelace added seven explanatory notes to her translation, which run about three times the length of the original. Her annotated translation has been called “the most important paper in the history of digital computing before modern times” (Bromley, “Introduction” in Babbage, Henry Prevost, Babbage’s Calculating Engines, xv). As Babbage never published a detailed description of the Analytical Engine, Ada’s translation of Menabrea’s paper, with its lengthy explanatory notes, represents the most complete contemporary account in English of this much-misunderstood machine.

"Babbage supplied Ada with algorithms for the solution of various problems, which she illustrated in her notes in the form of charts detailing the stepwise sequence of events as the machine progressed through a string of instructions input from punched cards" (Swade, The Cogwheel Brain, 165). 

These were the first published examples of  computer “programs,” though neither Ada nor Babbage used this term. She also expanded upon Babbage’s general views of the Analytical Engine as a symbol-manipulating device rather than a mere processor of numbers, suggesting that it might act upon other things besides number, were objects found whose mutual fundamental relations could be expressed by those of the abstract science of operations. . . . Supposing, for instance, that the fundamental relations of pitched sounds in the science of harmony and of musical composition were susceptible of such expression and adaptations, the engine might compose elaborate and scientific pieces of music of any degree of complexity or extent (p. 694) . . . Many persons who are not conversant with mathematical studies, imagine that because the business of the engine is to give its results innumerical notation, the nature of its processes must consequently be arithmetical and numerical, rather than algebraical and analytical. This is an error. The engine can arrange and combine its numerical quantities exactly as if they were letters or any other general symbols; and in fact it might bring out its results in algebraical notation, were provisions made accordingly (p. 713).

Much has been written concerning what mathematical abilities Ada may have possessed. Study of the published correspondence between her and Babbage is not especially flattering either to her personality or mathematical talents: it shows that while Ada was personally enamored of her own mathematical prowess, she was in reality no more than a talented novice who at times required Babbage’s coaching. Their genuine friendship aside, Babbage’s motives for encouraging Ada’s involvement in his work are not hard to discern. As Lord Byron’s only legitimate daughter, Ada was an extraordinary celebrity, and as the wife of a prominent aristocrat she was in a position to act as patron to Babbage and his engines, though she never did so.

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The Contributions of the Scheutz Brothers to the Early History of Difference Engines and the Calculating and Printing of Mathematical Tables 1843 – 1857

In 1843 Swedish authors and inventors Georg and Evard Scheutz, inspired by Dionysius Lardner’s account of Babbage’s Difference Engine, working in Stockholm, constructed the first working difference engine based on Babbage's design. One of the reasons the Scheutzs were able to build the engine, while Babbage could not, was that they were willing to machine the parts to lower tolerances than Babbage demanded, with the result that the Scheutz machine was prone to errors.

In 1849 Georg Scheutz published in Stockholm Nytt och enkelt sätt att lösa nummereqvationer af hogre och lägre grader efter Agardhska teorien: För praktiska behov [A new and simple method of solving numerical equations of higher and lower degree with the help of Agardh’s theory: For practical purposes]. and Bihang till skriften: Nytt och enkelt sätt att lösa nummereqvationer af hogre och lägre grader efter Agardhska teorien. Innehällande seriemetodens tillämpning vid bestämmandet af imaginära, lika, och nära hvarandra belägna rötter i en eqvation. Af C[arl] A[dolph] Agardh [1785-1859] . . . Utgifvet af Georg Scheutz [Appendix to the treatise: A new and simple method of solving numerical equations, using Agardh’s theory, containing the serial method used in determining imaginary, exact, and approximate roots of an equation. By C. A. Agardh, . . . edited by G. S.].

The Scheutz machine, of which three examples were built, was based upon Charles Babbage’s design for his famous Difference Engine No. 1, which Babbage worked on intermittently between 1822 and 1834 before abandoning the project uncompleted (only a small working portion, about one-ninth the size of the projected Difference Engine, was ever constructed; the uncompleted machine ended up costing the British Government over £17,000).

Georg Scheutz—described by Lindgren as an “auditor, printer, journalist and editor, political commentator, spokesman for technology, translator and inventor”—first learned of Babbage’s Difference Engine circa 1830. Although his imagination was immediately fired by the possibilities of such a machine, he was unable to begin designing his own version until 1834, when Dionysius Lardner published his detailed review of Babbage’s Difference Engine in the July issue of the Edinburgh Review. Drawing on the information in Lardner’s article, Scheutz and his teenage son Edvard began working on their own design for a difference engine, which was both simpler and cheaper to produce than Babbage’s machine.

The Scheutz difference engine no. 1, a prototype model built by Edvard, was completed in 1843 and certified by members of the Swedish Academy of Sciences. Despite this mark of favor, the Scheutzes were initially unable to stir up any interest or official support for their machine, either at home or abroad. They did no further work on the Scheutz machine until 1850, when, in response to renewed interest in machines for printing tables, they began working on the Scheutz difference engine no. 2.

However, the Scheutz machine no. 1 did not lie entirely fallow during the seven years between 1843 and 1850, for in 1849, Georg Scheutz used it to produce and print a table of a polynomial of the third degree, which he published in Nytt och enkelt sätt att lösa nummereqvationer af hogre och lägre grader efter Agardhska teorien. This little one-column table, found on p. 74 of Scheutz’s pamphlet, is the earliest known automatically produced numerical table.

"In [Scheutz’s Nytt och enkelt sätt att lösa nummereqvationer af hogre och lägre grader efter Agardhska teorien] he gave an exposition of the method of solving equations by the method of differences, which the professor of botany, mathematician and latterly bishop Carl Adolph Agardh had presented in 1809. In an addendum he remarks that while the method is excellent, it is time consuming when used on equations of high degree. He then adds that this disadvantage could be removed if one 'could assign the laborious and time consuming figure work to some assistant, that never tired, never made an error and dealt with the numerical calculations for the higher degrees as swiftly and certainly as those for the first degree.” Georg Scheutz notes that such an assistant does in fact exist and he gives an example of a stereotyped table calculated and printed by the first engine. . . . The table shows that Scheutz still was fascinated by the machine’s capability to solve equations. But more importantly, this table is the only existing illustration [emphasis ours] of what the Scheutz prototype engine could do. It is also the oldest automatically made numerical table in the world, which has been preserved " (Lindgren, Glory and Failure: The Difference Engines of Johann Müller, Charles Babbage and Georg and Edvard Scheutz [1987] 138-39).

Lindgren was the first to note the existence of this numerical table generated by the Scheutz difference engine no. 1. Prior to this, the first examples of tables produced by a Scheutz engine were thought to have been contained in the Scheutz’s Specimens of Tables, Calculated, Stereomoulded and Printed by Machinery (London, 1857), which the Scheutzes produced, probably with Charles Babbage's cooperation, in both English and French editions as a means of showcasing the improved Scheutz difference engine no. 2, which was produced by the brothers in 1853.

The standard histories of computing, including Aspray’s Computing before Computers (1990), contain no reference to the table printed by the Scheutz difference engine no. 1. 

Merzbach, Georg Scheutz and the First Printing Calculator (1977). 


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The First Published Computer Programs, Translated and Augmented by Lord Byron's Daughter October 1843

In October 1843, Augusta Ada King, Countess of Lovelace, daughter of Lord Byron, translated Menabrea’s paper, "Notions sur la machine analytique de M. Charles Babbage" (1842).  Her "Sketch of the Analytical Engine Invented by Charles Babbage . . . with Notes by the Translator" published in Scientific Memoirs, Selected from the Transactions of Foreign Academies of Science and Learned Societies 3 (1843): 666-731 plus 1 folding chart, was the first edition in English of the the first published account of Babbage’s Analytical Engine, and, more significantly, of its logical design.

In 1840 Babbage traveled to Torino to present to a group of Italian scientists an account of the Engine. Babbage’s talk, complete with drawings, models and mechanical notations, emphasized the Engine’s signal feature: its ability to guide its own operations. It also included the first computer programs though Babbage did not use that word. In attendance at Babbage’s lecture was the young Italian mathematician Luigi Federico Menabrea (later Prime Minister of Italy), who prepared from his notes an account of the principles of the Analytical Engine, which he published in French in 1842.

In keeping with the more general nature and immaterial status of the Analytical Engine, Menabrea’s account dealt little with mechanical details. Instead he described the functional organization and mathematical operation of this more flexible and powerful invention. To illustrate its capabilities, he presented several charts or tables of the steps through which the machine would be directed to go in performing calculations and finding numerical solutions to algebraic equations. These steps were the instructions the engine’s operator would punch in coded form on cards to be fed into the machine; hence, the charts constituted the first computer programs. Menabrea’s charts were taken from those Babbage brought to Torino to illustrate his talks there (Stein, Ada: A Life and Legacy, 92).

Menabrea’s paper was translated into English by Babbage’s close friend Ada, Countess of Lovelace, daughter of the poet Byron and a talented mathematician in her own right. At Babbage’s suggestion, Lady Lovelace added seven explanatory notes to her translation, which run about three times the length of the original. Her annotated translation has been called “the most important paper in the history of digital computing before modern times” (Bromley, “Introduction” in Babbage, Henry Prevost, Babbage’s Calculating Engines, xv). As Babbage never published a detailed description of the Analytical Engine, Ada’s translation of Menabrea’s paper, with its lengthy explanatory notes, represents the most complete contemporary account in English of this much-misunderstood machine.

Babbage supplied Ada with algorithms for the solution of various problems, which she illustrated in her notes in the form of charts detailing the stepwise sequence of events as the machine progressed through a string of instructions input from punched cards (Swade, The Cogwheel Brain, 165). This was the first published example of a computer “program,” though neither Ada nor Babbage used this term. She also expanded upon Babbage’s general views of the Analytical Engine as a symbol-manipulating device rather than a mere processor of numbers, suggesting that it might act upon other things besides number, were objects found whose mutual fundamental relations could be expressed by those of the abstract science of operations. . . . Supposing, for instance, that the fundamental relations of pitched sounds in the science of harmony and of musical composition were susceptible of such expression and adaptations, the engine might compose elaborate and scientific pieces of music of any degree of complexity or extent (p. 694) . . . Many persons who are not conversant with mathematical studies, imagine that because the business of the engine is to give its results in numerical notation, the nature of its processes must consequently be arithmetical and numerical, rather than algebraical and analytical. This is an error. The engine can arrange and combine its numerical quantities exactly as if they were letters or any other general symbols; and in fact it might bring out its results in algebraical notation, were provisions made accordingly (p. 713).

Much has been written concerning what mathematical abilities Ada may have possessed. Study of the published correspondence between her and Babbage (see Toole 1992) is not especially flattering either to her personality or mathematical talents: it shows that while Ada was personally enamored of her own mathematical prowess, she was in reality no more than a talented novice who at times required Babbage’s coaching. Their genuine friendship aside, Babbage’s motives for encouraging Ada’s involvement in his work are not hard to discern. As Lord Byron’s only legitimate daughter, Ada was an extraordinary celebrity, and as the wife of a prominent aristocrat she was in a position to act as patron to Babbage and his engines (though she never in fact did so).

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1875 – 1900

Baldwin & Odhner Invent Calculators Using a True Variable-Toothed Gear Circa 1875

Detail of image from Baldwin's Calculating Machine. See larger image and resize image for complete picture.

Frank Stephen Baldwin.

Odhner's arithmometer.

Willgodt Theophil Odhner.

About 1875 engineer Frank S. Baldwin of Philadelphia and Willgot Theophil Odhner, a Swedish engineer and entrepreneur working in St. Petersburg, Russia, independently invented calculators using a true variable-toothed gear. This was the first real advance in mechanical calculating technology since Gottfried Leibniz's stepped drum (1673). These calculators were called "pinwheel calculators."

The greater ease of use of this technology, its general reliability, and the compact size of the equipment incorporating it caused an explosion of sales in the calculator industry.

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The Earliest Exhibition Exclusively of Scientific Instruments 1876

The earliest international exposition exclusively of scientific instruments was held at the South Kensington Museum, London in 1876.  As a record of the exhibition the South Kensington Museum published a Handbook to the Special Loan Collection of Scientific Apparatus 1876 (London 1876). The section on calculating machines on pages 23-34 was written by H. J. S. Smith, and included those of Babbage, Scheutz, Thomas de Colmar, and Grohmann. None were illustrated. James Clerk Maxwell contributed two chapters in this guide, Peter Guthrie Tait wrote one, and Thomas Henry Huxley wrote one.  A French translation of this work was published in Paris also in 1876.

The South Kensington Museum was later merged into the Science Museum in London.

Hook & Norman, Origins of Cyberspace 369.

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Abdank-Abakanowicz Invents the Integraph 1878

In 1878 Bruno Abdank-Abakanowicz, a mathematician, inventor and electrical engineer, invented the integraph, a form of integrator.

"The integraph is an elaboration and extension of the planimeter, an earlier, simpler instrument used to measure area. It is a mechanical instrument capable of deriving the integral curve corresponding to a given curve. Hence, it is capable of solving graphically a simple differential equation.

"Sets of partial differential equations are commonly encountered in mathematical physics. Most branches of physics such as aerodynamics, electricity, acoustics, plasma physics, electron-physics and nuclear energy involve complex flows, motions and rates of change which may be described mathematically by partial differential equations. A well-established example from electromagnetics is the set of partial differential equations known as Maxwell's equations.

"In practice, differential equations can be difficult to integrate, that is to solve. The integraph is capable of solving only simple differential equations. The need to handle sets of more complex non-linear differential equations, led Vannevar Bush to develop the Differential Analyzer at MIT in the early 1930s. In turn, limitations in speed, capacity and accuracy of the Bush Differential Analyzer provided the impetus for the development of the ENIAC during World War II.

"Abdank-Abakanowicz’s instrument could produce solutions to a commonly encountered class of simple differential equations of the form dy/dx = F(x) so that y = ò F(x)dx. The basic approach was to draw a graph of the function F and then use the pointer on the device to trace the contour of the function. The value of the integral could then be read from the dials. The concept of the instrument was taken up and soon put into production by such well known instrument makers as the Swiss firm of Coradi in Zurich" (From Gordon Bell's website, accessed 09-01-2010).

Abdank-Abakanowicz published a monograph entitled Les Intégraphes (Paris, 1886).

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Charles Sanders Pierce Recognizes that Logical Operations Could be Carried Out by Electrical Switching Circuits 1886

In 1886 American American philosopher, logician, mathematician, and scientist Charles Sanders Peirce recognized that logical operations could be carried out by electrical switching circuits. This idea he mentioned in a letter to his former student Allan Marquand

Prior to receiving Peirce's letter, in 1881-82, inspired by William Stanley Jevons' logical piano, Marquand built a mechanical logical machine that is still exant according to the Wikipedia article on Marquand. Marchand first published a description of his mechanical machine in 1885. After receiving Peirce's letter, in 1887 Marquand "outlined a machine to do logic using electric circuits. This necessitated his development of Marquand diagrams" (Wikipedia article on Allan Marchand, accessed 10-08-2013).

In October 2013 history-computer.com reproduced a circuit diagram for the electromagnetic logical machine in Marquand's archive that was made about 1890. Other than diagrams of this kind there is no evidence that Marchand or Peirce ever built an electrical logic machine. 

The Peirce-Marchand communication or collaboration on the use of electrical switching circuits to carry out logical operations is a remarkable precursor of ideas later developed by Claude Shannon in his thesis of 1937.

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Dorr E. Felt Invents the Comptometer 1887

Early comptometer.

Dorr E. Felt.

In 1887 American inventor Dorr E. Felt introduced the Comptometer, a non-printing key-driven calculating machine whose chief advantages were speed, versatility, and ease of use.

"Use. For each digit a push button from 1 to 9 is selected which rotates a Pascal-type wheel with the corresponding number of increments. Numbers are subtracted by adding the complement (shown in smaller numbers). The carrying of tens is accomplished by power generated by the action of the keys and stored in a helical spring, which is automatically released at the proper instant to perform the carry.  

"Through effective marketing and training of skilled operators versed in complement arithmetic at Comptometer Schools, these machines became the workhorse of the accounting profession in the first part of the [20th] century. They never successfully advanced into the electro-mechanical era, but remained purely mechanical, two-function adding and subtracting machines" (Gordon Bell's website, accessed 10-12-2011).

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The Most Complete Work on Babbage's Computers 1889

Charles Babbage’s son Henry Prevost Babbage completed and published his father’s unfinished edition of writings on the Difference Engine No. 1 and the Analytical Engine, together with a listing of his father’s unpublished plans and notebooks. These appear under the title of Babbage’s Calculating Engines.

This work was the principal source of information for the technical operation of Babbage’s Difference and Analytical engines. Toward the end of his life, Babbage began assembling his own and other’s previously published writings on his Difference and Analytical Engines with the intent of publishing a history of his work designing the machines, and descriptions of the way that the machines would operate. However, Babbage died before he could accomplish this task. He had the first 294 pages of this work typeset and printed on slightly varying qualities of paper during his lifetime. The differences in the paper used for portions of the work would suggest that sections were printed intermittently rather than all at one time. It would appear that Babbage’s purpose in producing this work was to collect the most significant published writings on his calculating engines, most of which had appeared as obscure pamphlets or in little-read journals, together with a listing of what remained unpublished, including all of Babbage’s notebooks and engineering drawings (listed on pp. 271-294), in the hope that his unfinished projects might be completed at some future date.

Almost twenty years after Babbage’s death, his youngest son, Major-General Henry Prevost Babbage, to whom Babbage had bequeathed his parts for his calculating engines, and everything else pertaining to them, completed the book, incorporating the printed sheets that Babbage had produced along with concluding material, reflecting his own frustrated efforts to effect realization of Babbage’s engines. Were it not for this volume, and for the bibliography of Babbage’s works published both here (on the last three printed pages of the book) and in Babbage’s autobiography, Babbage’s achievements might have been forgotten. Henry Babbage also completed six small demonstration pieces of the Difference Engine No. 1, and in 1910 at the age of 86, Henry Babbage also completed an experimental four-function calculator for the Mill for the Analytical Engine.  This was the only portion of the Analytical Engine that was ever produced in metal.

As it turned out Babbage’s designs were not implemented until the 20th century because in the era of human computers there was no pressing need for the machines that Babbage envisioned and designed. Yet because of these published works, Babbage’s ambitions and his ideas remained alive in the minds of people working in mechanical computation long after his technology had fallen into obsolescence. When Vannevar Bush suggested in 1936 that electromechanical technology might be the way to realize “Babbage’s large conception” of the Analytical Engine, he cited this volume among his references; and in building the electromechanical Harvard Mark I, Howard Aiken saw himself fulfilling Babbage’s ambition. However, some experts have inferred that Aiken’s knowledge of Babbage’s work may have been limited to what he read in Babbage’s autobiography, Passages from the Life of a Philosopher, as Aiken did not include conditional branching in the design of the Mark I—a key idea that Babbage designed into the Analytical Engine.

Hyman, Charles Babbage, Pioneer of the Computer, 254. Van Sinderen, Alfred W. "The Printed Papers of Charles Babbage" Annals of the History of Computing, 2 (April 1980) :169-185 mentions in item CB80, that Babbage listed a History of the Analytical Engine as being “in the press” in 1864.

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The Burroughs Dependable Key-Driven Printing Adding Machine 1892

In 1892 American inventor William Seward Burroughs of St. Louis, Missouri, founder of the American Arithmometer Company (1886; (Burroughs Adding Machine Company 1904) began commercial production of his dependable key-driven printing adding machine.

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The Millionaire Calculator 1893

Millionaire mechanical calculator.

In 1893 the "Millionaire" mechanical calculator, about the size of a small desk top, was introduced in Switzerland. The "Millionaire" was the first commercially successful calculator that could perform multiplication directly, rather than by repeated addition. It was designed by Otto Steiger, a Swiss engineer and was first patented in Germany in 1892. Patents were issued in France, Switzerland, Canada and the USA in 1893. Production by Hans W. Egli of Zurich started in 1893, and continued to 1935. Most models were driven by hand-crank but some were electrified.

Roughly 4000-5000 Millionaires were sold. 

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d'Ocagne Publishes the First Systematic Classification of Calculating Machines 1894

In 1894 Philbert Maurice d'Ocagne published Le Calcul simplifiée par procèdes mécaniques et graphiques. This contained the first systematic classification of calculating machines.

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1900 – 1910

A New Version of Babbage's Analytical Engine, Lost 1908 – 1914

IN 1908 Irish accountant Percy Ludgate, working in Dublin, designed a general purpose programable computer about which he published "On a proposed analytical engine," Scientific Proceedings of the Royal Dublin Society, n.s., 12 (1909-10) 77-91. This described "the result of about six years' work, undertaken . . . with the object of designing machinery capable of performing calculations, however, intricate or laborious, without the immediate guidance of the human intellect" (p. 77).

Ludgate's efforts followed about eighty years after Babbage began designing his Analytical Engine, and although Ludgate knew nothing of Babbage's work until after he had completed the first design of his own machine, he was "greatly assisted in the more advanced stages of the problem by, and [received] valuable suggestions from, the writings of that accomplished scholar" (p. 78).

Ludgate was the only person to attempt to build a general purpose programable computer between Babbage and Howard Aiken, whose Harvard Mark I became operational in the early 1940s. Ludgate's machine, as designed, was much smaller than Babbage's, handling 192 variables of 20 figures each compared to Babbage's 1000 variables of 50 figures each, and using "shuttles" to store the variables instead of Babbage's bulkier columns of wheels.  Ludgate was never able to obtain funding to build his machine and he died at the early age of 39. His drawings of his machine were lost; the only records are in his 1909-10 paper, and in a very brief account embedded in Ludgate's report on automatic calculating machines published in the 1914 Handbook of the Napier Tercentenary Celebration (also issued as Modern Instruments and Methods of Calculation). Randell, Origins of Digital Computers (3d ed.) 73-87 reprints the text. Norman, From Gutenberg to the Internet (2005) Reading 6.3 reprints Ludgate's 1914 article.

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1910 – 1920

Summarizing the State of the Computer / Calculator Industry Prior to World War I July 24 – July 27, 1914

The Napier Tercentenary Celebration  marking the three hundredth anniversary of the publication of Napier's Mirifici logarithmorum canonis descriptio (1614), was held at the Royal Society of Edinburgh from July 24 to July 27, 1914 — just five days before the start of World War I. Participants in the exhibition included individuals and companies from Scotland, England, France, and Germany. The meeting was intended to include a colloquium on the mathematics of computation, but that was canceled because war was considered imminent.

A celebration of Napier's pivotal role in the history of calculation, the exhibition featured displays of many different types of calculating machines, as well as exhibits of other aids to calculation such as mathematical tables, the abacus and slide rules, planimeters and other integrating devices, and ruled papers and nomograms. These were described in the Napier Tercentenary Celebration. Handbook to the Exhibition, which contained separate sections, with chapters by various contributors, devoted to each type of calculating device. Among the notable chapters is Percy E. Ludgate's "Automatic Calculating Machines" (pp. 124-27): apart from Ludgate's "On a proposed analytical machine" (Scientific Proceedings of the Royal Dublin Society 12 [1909]: 77-91), this chapter contains the only discussion of his improvements to Babbage's Analytical Engine (none of which was ever realized). Also of note is W. G. Smith's "Notes on the Special Development of Calculating Ability" (pp. 60-68), discussing human "lightning calculators" and mathematically gifted "idiot savants," such as were employed by Gauss. Prior to the advent of electronic digital computers, these human computers were often faster than their mechanical counterparts.

The most widely used tools for calculation at the time of the Napier tercentenary were mathematical tables, which are thoroughly surveyed, explained, and described in the Handbook (bibliographical descriptions of the rare mathematical tables exhibited were published the following year in the Napier Tercentenary Memorial Volume. The Handbook also contains a large illustrated section on calculating machines, which were divided into four types: (1) stepped-gear machines based on the Leibniz wheel, such as those of Charles Xavier Thomas de Colmar; (2) machines with variable-toothed gears, such as the Brunsviga; (3) key-set machines like those made by Burroughs; and (4) key-driven machines such as those made by Felt and Tarrant.

The Handbook was published in two forms: a softcover version presented to those who registered for the exhibition; and a hardcover version issued for sale under the title Modern Instruments and Methods of Calculation. Relatively few copies of the softcover version seem to have been distributed at the exhibition, partly because the exhibition took place in Edinburgh, but mainly because war broke out just after it began. Most copies were bound in cloth and sold in London.

"The events of the First World War caused no less upheaval in the world of computing than in the rest of society. A great many technical changes, such as the ever-increasing use of punched-card accounting machines, were to cause computing to assume a different character in the time between the two World Wars. Thus the Handbook should be viewed as a report on the state of the art just before these changes were to begin taking place" (Williams 1982, [x]).  

Hook & Norman, Origins of Cyberspace (2001) no. 322.

(This entry was last revised on April 28, 2014.)

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Eccles & Jordan Invent the Flip-Flop Circuit, the Basis for Electronic Memory June 21, 1918

On June 21, 1918 British physicists and professors of engineering at London's City and Guilds Technical College William Henry Eccles and Frank Wilfred Jordan filed a patent for "Improvements in Ionic Relays." The patent specification 148,582 was published in 1920. It was initially called the Eccles–Jordan trigger circuit and consisted of two active elements (vacuum tubes).  

Early flip-flops were known variously as trigger circuits or multivibrators. Prior to the invention of electronic computing Eccles and Jordan viewed their invention as a "method of relaying or magnifying in electrical ciruits for use in telegraphy and telephony." However, a flip-flop circuit has two stable states and, as Claude Shannon pointed out in his Mathematical Theory of Communication (1948), a flip-flop can be used to store one bit of information. Flip-flop circuits operate using Boolean algebra (AND, OR, NOT). Thus, with the invention of electronic computing using vacuum tubes as switches, flip-flops became the basic storage element in sequential logic used in digital circuitry, and the basis for electronic memory.

In September 1919 Eccles and Jordan described the flip-flop in a brief one-page paper, "A trigger relay utilizing three-electrode thermionic vacuum tubes," The Electrician, vol. 83, (September 19, 1919) p. 298. However, the patent, filed the previous year, and consisting of 5 pages, remains the first description of this invention.

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1930 – 1940

Key Contributions of Konrad Zuse to the History of Computer Design and Software 1934 – 1958

Konrad Zuse made numerous original contributions to computer design and software that predated American and English developments, but because Zuse worked in Nazi Germany his ideas were unknown outside of Germany until well after World War II, and thus had no influence on the development of the computer industry in America and England. While completing his engineering degree at the Technische Universität Berlin in 1934, Zuse,realized that an automatic calculator would need only a control, a memory, and an arithmetic unit. On April 11, 1936 Zuse applied for a patent on his electromagnetic, program-controlled calculator, called the Z1, which he built in the living room of his parents’ apartment in Berlin. Zuse completed the ZI, which had 30,000 parts, in 1938. Independently of Claude Shannon, Zuse developed a form of symbolic logic to assist in the design of the binary circuits

The Z1 was the first freely programmable, binary-based calculating machine ever built, but it did not function reliably, and it was destroyed in World War II. Zuse's patent application is the only surviving documentation of Zuse's prewar work on computers. Between 1986 and 1989 Zuse and three associates created a replica of the Z1, which is preserved in the Deutsche Technikmuseum, Berlin.

With his associate Helmut Schreyer, Zuse began work on his Z2 shortly after completing the Z1. In 1939 the men completed the Z2 machine in Berlin. It used the same kind of mechanical memory as the Z1, but used 800 relays in the arithmetic and control units. On October 15, 1939 Helmut Schreyer wrote a memorandum concerning the Z2, Rechnische Rechenmachine (unpublished at the time), in which he stated that it would be possible to build a computer with vacuum tubes that would process “10,000 operations per second.” This memorandum and the rest of Zuse's and Schreyer's ideas only became known in the west after World War II.

In 1940 the German government began funding Zuse's work through the Aerodynamische Versuchsanstalt (AVA, Aerodynamic Research Institute, forerunner of the Deutsches Zentrum für Luft- und Raumfahrt e.V, DLR). At this time Zuse built the S1 and S2 computers —special purpose machines for computing aerodynamic corrections to the wings of radio-controlled flying bombs.

"The S2 featured an integrated analog-to-digital converter under program control, making it the first process-controlled computer. These machines contributed to the Henschel Werke Hs 293 and Hs 294 guided missiles developed by the German military between 1941 and 1945, which were the precursors to the modern cruise missile. The circuit design of the S1 was the predecessor of Zuse's Z11. Zuse believed that these machines had been captured by occupying Soviet troops in 1945" (Wikipedia article on Konrad Zuse, accessed 03-03-2012).

Continuing to work in Berlin, with the assistance of Helmut Shreyer, Zuse completed his Z3 machine on May 12, 1941. This was the world’s first fully functional Turing-complete electromechanical digital computer—with twenty-four hundred relays. The Z3 ran programs punched into rolls of discarded movie film. In 1944 it was destroyed in bombing raids. Also in 1941 Schreyer received his doctorate in telecommunications engineering from the Technische Universität Berlin with a dissertation on the use of vacuum-tube relays in switching circuits. Schreyer converted Zuse’s logical designs into electronic circuits, building a simple prototype of an electronic computer with 100 vacuum tubes, which achieved a switching frequency of 10,000 Hz. Because no one outside of Germany had any knowledge of the Z3, Zuse's design had no influence on the development of computing in the the United States or England during or after World War II. In 2012 there was a replica of the Z3 on display in the Deutsches Museum, Munich.

In 1942 Zuse started work on the Z4 electromechanical computer in Berlin, completing the work shortly before V-E Day in 1945. Built by his company, Zuse Apparatebau, the Z4 was the world's first commercial digital computer. To safeguard it against bombing, the machine was dismantled and shipped from Berlin to a village in the Bavarian Alps. In 1950 it was refurbished, modified, and installed at ETH in Zurich. For several years it was the only working electronic digital computer in continental Europe, and it remained operational in Zurich until 1955. It is preserved in the Deutsches Museum in Munich.

"The Z4 was very similar to the Z3 in its design but was significantly enhanced in a number of respects. The memory consisted of 32-bit rather than 22-bit floating point words. A special unit called the Planfertigungsteil (program construction unit), which punched the program tapes made programming and correcting programs for the machine much easier by the use of symbolic operations and memory cells. Numbers were entered and output as decimal floating point even though the internal working was in binary. The machine had a large repertoire of instructions including square root, MAX, MIN and sign. Conditional tests included tests for infinity. When delivered to ETH Zurich the machine had a conditional branch facility added and could print on a Mercedes typewriter. There were two program tapes where the second could be used to hold a subroutine (originally six were planned).

"In 1944 Zuse was working on the Z4 with around two dozen people, including several women. Some engineers who worked at the telecommunications facility of the OKW also worked for Zuse as a secondary occupation. To prevent it from falling into the hands of the Soviets, the Z4 was evacuated from Berlin in February 1945 and transported to Göttingen. The Z4 was completed in Göttingen in a facility of the Aerodynamische Versuchsanstalt (AVA, Aerodynamic Research Institute), which was headed by Albert Betz. But when it was presented to scientists of the AVA the roar of the approaching front could already be heard, so the computer was transported with a truck of the Wehrmacht to Hinterstein in Bad Hindelang, where Konrad Zuse met Wernher von Braun" (Wikipedia article on Z4, accessed 01-01-2015).

For the Z4 Zuse developed Plankalkül, the first "high-level" non-von Neumann programming language. Some of his earliest notes on the topic date to 1941. The language was well-developed by 1945. Because of war time secrecy, and Zuse's efforts to commercialize the Z3 computer and its sucessors, Zuse did not publish anything on Plankalkühl at the time he developed it. Zuse wrote a book on the subject in 1946 but this remained unpublished until it was edited many years later for Internet publication. In 1948 he published a summary paper,  "Über den Allgemeinen Plankalkül als Mittel zur Formulierung schematisch-kombinativer Aufgaben", Archiv der Mathematik I (1948) 441-449. However, this did not attract much attention.

" . . . for a long time to come programming a computer would only be thought of as programming with machine code. The Plankalkül was eventually more comprehensively published in 1972 and the first compiler for it was implemented in 1998. Another independent implementation followed in the year 2000 by the Free University of Berlin" (Wikipedia article on Plankalkühl, accessed 12-04-2011).

Because of his Nazi affiliation Zuse was not allowed to get back into the computer industry until the 1950s. In 1958 he produced the Z22, the first commercial electronic digital computer produced in Germany. The Z22 used vacuum tubes—a relatively late date for that technology, as most American computer companies switched to solid state by 1957. Zuse's company, Zuse KG, became the first independent German electronic computer company. It was eventually purchased by Siemens.

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IBM's German Subsidiary, Deutsche Hollerith Maschinen, Introduces the First Automatic Sequence-Controlled Calculator September 1935

In September 1935 IBM’s German subsidiary, Deutsche Hollerith Maschinen (Dehomag) introduced the Dehomag D11 tabulator, the first automatic sequence-controlled calculator, incorporating internal instructions programmed with a plug board.

Kistermann, "The way to the first automatic sequence-controlled calculator: The 1935 DEHOMAG D 11 tabulator," IEEE Annals of the History of Computing XVII (1995): 33-49.

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Alan Turing Publishes "On Computable Numbers," Describing What Came to be Called the "Turing Machine" November 30, 1936

In issues dated November 30 and December 23, 1936 of the Proceedings of the London Mathematical Society English mathematician Alan Turing published "On Computable Numbers", a mathematical description of what he called a universal machine— an astraction that could, in principle, solve any mathematical problem that could be presented to it in symbolic form. Turing modeled the universal machine processes after the functional processes of a human carrying out mathematical computation. In the following issue of the same journal Turing published a two page correction to his paper.

Undoubtedly the most famous theoretical paper in the history of computing, "On Computable Numbers" is a mathematical description an imaginary computing device designed to replicate the mathematical "states of mind" and symbol-manipulating abilities of a human computer. Turing conceived of the universal machine as a means of answering the last of the three questions about mathematics posed by David Hilbert in 1928: (1) is mathematics complete; (2) is mathematics consistent; and (3) is mathematics decidable.

Hilbert's final question, known as the Entscheidungsproblem, concerns whether there exists a defiinite method—or, in the suggestive words of Turing's teacher Max Newman, a "mechanical process"—that can be applied to any mathematical assertion, and which is guaranteed to produce a correct decision as to whether that assertion is true. The Czech logician Kurt Gödel had already shown that arithmetic (and by extension mathematics) was both inconsistent and incomplete. Turing showed, by means of his universal machine, that mathematics was also undecidable.

To demonstrate this, Turing came up with the concept of "computable numbers," which are numbers defined by some definite rule, and thus calculable on the universal machine. These computable numbers, "would include every number that could be arrived at through arithmetical operations, finding roots of equations, and using mathematical functions like sines and logarithms—every number that could possibly arise in computational mathematics" (Hodges, Alan Turing: The Enigma [1983] 100). Turing then showed that these computable numbers could give rise to uncomputable ones—ones that could not be calculated using a definite rule—and that therefore there could be no "mechanical process" for solving all mathematical questions, since an uncomputable number was an example of an unsolvable problem.

From 1936 to 1938 Mathematician Alan Turing spent more than a year at Princeton University studying mathematical logic with Alonzo Church, who was pursuing research in recursion theory. In August 1936 Church gave Turing's idea of a "universal machine" the name "Turing machine." Church coined the term in his relatively brief review of "On Computable Numbers." With regard to Turing's proof of the unsolvability of Hilbert's Entscheidungsproblem, Church acknowledged that "computability by a Turing machine. . . has the advantage of making the identification with effectiveness in the ordinary (not explicitly defined) sense evident immediately—i.e. without the necessity of proving elementary theorems." Church working independently of Turing, had arrived at his own answer to the Entscheidungsproblem a few months earlier. Norman, From Gutenberg to the Internet, Reading 7.2.  

Independently of Alan Turing, mathematician and logician Emil Post of the City College of New York developed, and published in October 1936, a mathematical model of computation that was essentially equivalent to the Turing machine. Intending this as the first of a series of models of equivalent power but increasing complexity, he titled his paper Formulation 1. This model is sometime's called "Post's machine" or a Post-Turing machine.

In 1937 Turing and John von Neumann had their first discussions about computing and what would later be called “artificial intelligence” (AI). Always interested in practical applications of computing as well as theory, also while at Princeton, in 1937, believing that war with Germany was inevitable, Turing built in an experimental electromechanical cryptanalysis machine capable of binary multiplication in a university machine shop. After returning to England, on September 4, 1939, the day after Britain and France declared war on Germany, Turing reported to the Government Code and Cypher SchoolBletchley Park, in the town of Bletchley, England.

♦ In June 2013 it was my pleasure to purchase the famous copy of the offprint of "On Computable Numbers" along with the offprint of "On Computable Numbers . . . A Correction" that Turing presented to the English philosopher R. B. Braithwaite. One of very few copies in existence of the offprint, and possibly the only copy in private hands, the offprint sold for £205,000.  It was a price record for any offprint on a scientific or medical subject, for any publication in the history of computing, and probably the highest price paid for any scientific publication issued in the twentieth century.

Norman, From Gutenberg to the Internet, Reading 7.1. Hook & Norman, Origins of Cyberspace (2002) No. 394. 

(This entry was last revised on 12-31-2014.)

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George Stibitz Builds the First Electromechanical Computers in America November 1937 – October 1941

In November 1937 George Stibitz, a research mathematician at Bell Telephone Labs in New York City, built a binary adder out of a few light bulbs, batteries, relays and metal strips cut from tin cans on his kitchen table. This device was similar to a theoretical design described a few months earlier by Claude Shannon in his master's thesis. Stibitz's "Model K" (for “Kitchen”) was the first electromechanical computer built in America.

In 1939 Stibitz and Samuel Williams of Bell Labs in New York City began construction of the Complex Number Calculator (later known as the Bell Labs Model I). This machine was called “the first electromechanical computer for routine use.” It used telephone relays and coded decimal numbers as groups of four binary digits (bits) each.

On January 8, 1940 the Complex Number Calculator was operational. On September 11 the machine, located in New York, was demonstrated via a remote teletype terminal at the American Mathematical Association Meeting in Dartmouth College, New Hampshire. This was the first demonstration of remote computing. At the demonstration mathematician Norbert Wiener, and physicist John Mauchly spent a lot of time experimenting with the system. 

Inspired by the demonstration of remote computing using Wiener sent a letter to Vannevar Bush enclosing a “Memorandum on the Mechanical Solution of Partial Differential Equations.” This outlined a machine that had all the features of an electronic digital computer except for a stored program. The memorandum was not published until it appeared in Wiener’s Collected Works issued from 1976 to 1984.

On October 8, 1941 mathematician and computing pioneer Edmund C. Berkeley, an actuary at the Prudential Insurance Company in Boston, wrote a report on the possible application of Stibitz’s Complex Number Calculator for insurance-company calculations. This was one of the earliest reports on the application of an electromechnical computer in industry.

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Key Aspects of the Development of the Harvard Mark 1 and its Software November 1937 – 1946

American computing pioneer Howard H. Aiken first conceived of building a powerful, large-scale calculating machine in 1935 while pursuing graduate studies in physics at Harvard University. In 1937, after Aiken had become a professor of applied mathematics at Harvard's Graduate School of Engineering, he proposed his idea to a number of calculating-machine manufacturers, drafting a proposal for an automatic calculating machine, and receiving several rejections before finally convincing IBM to undertake the project. The project, known initially as Automatic Sequence Controlled Calculator (ASCC), and later called the Harvard Mark I, was partly funded by money from the United Statses Navy; the remainder came from IBM, whose president, Thomas J. Watson, viewed the undertaking as good publicity and as a showcase for IBM's talents. 

Aiken's machine began construction in May 1939 at IBM's North Street Laboratory in Endicott, New York. The chief engineers on the project were Clair D. Lake, James W. Bryce, Francis E. Hamilton, and Benjamin Durfee; these men were responsible for translating Aiken's design ideas into workable machinery, and Aiken never hesitated to acknowledge them as co-inventors of the Mark I. To give the machine a beautiful appearance, Watson commissioned the avant-garde industrial designer Norman Bel Geddes to design a metal cabinet for the machine. Geddes's work gave the machine a very modernistic look. By January 1943  the machine was operational at IBM Endicott Labs under wartime security. The completed electromechanical calculating machine weighed five tons.

Construction of the Mark I was completed in early 1943, and a year later the machine was dismantled and shipped to Harvard, where it became operational in May 1944. he electromechanical machine solved addition problems in less than a second, multiplication in six seconds, and division in 12 seconds. Grace Hopper wrote some of its first programs, which ran on punched tape.The machine was officially presented to Harvard by IBM at a dedication ceremony held on August 7. Unfortunately, the press release announcing the event slighted IBM by describing Aiken as the machine's sole inventor, ignoring the crucial role IBM had played in its creation. This regrettable faux pas infuriated Watson, who was in attendance at the ceremony, and put an end to any hopes of a continuing partnership between IBM and Harvard. 

In 1945, probably in October, Aiken published Tables of the Modified Hankel Functions of Order One-Third and of their Derivatives. These tables, calculated by the Harvard Mark I were the first published mathematical tables calculated by a programmed automatic computer, finally fulfilling the dream of Charles Babbagefirst expressed in 1822. Calculating these tables required the equivalent of forty-five days of computer processing time on the Mark I. Prior to the Mark I, calculating the tables would have required years of human computation.

In 1946 Aiken and Grace Hopper published Manual of Operation for the Automatic Sequence Controlled Calculator. The instruction sequences scattered throughout this volume on the Harvard Mark I were among the earliest published examples of digital computer programs. Aiken saw himself as Babbage's intellectual successor, and in an excellent historical introduction to this technical manual he and Hopper placed the Harvard Mark I in its historical context.  The introduction began with the following quotation from Babbage's autobiography (1864):

"If, unwarned by my example, any man shall undertake and shall succeed in really constructing an engine embodying in itself the whole of the executive department of mathematical analysis upon different principles or by simpler mechanical means, I have no fear of leaving my reputation in his charge, for he alone will be fully able to appreciate the nature of my efforts and the value of their results."  

I. B. Cohen, in his biography of Aiken, Portrait of a Computer Pioneer (2000) pointed out that Aiken was not well informed about the actual design of Babbage's Analytical Engine when he was designing the Mark I; otherwise Aiken would have included conditional branch facilities in its original design. Before designing the machine Aiken seems to have read Babbage's autobiography rather than the posthumous Babbage's Calculating Engines, in which more details of the design of the Analytical Engine were given. An imposing thick quarto with large photographs of the very modernistic looking Mark I, this technical volume full of computer programs must have been perceived as radically new when it was published. The computer historian Paul Ceruzzi implies as much in the following description:

"[The Harvard Mark I] manual was a milepost that marked the state of the art of machine computation at one of its critical places: where, for the first time, machines could automatically evaluate arbitrary sequences of arithmetic operations. Most of this volume (pp. 98-337, 406-557) consists of descriptions of the Mark I's components, its architecture, and operational codes for directing it to solve typical problems. . . . The Manual is one of the first places where sequences of arithmetic operations for the solution of numeric problems by machine were explicitly spelled out. It is furthermore the first extended analysis of what is now known as computer programming since Charles Babbage's and Lady Lovelace's writings a century earlier. The instruction sequences, which one finds scattered throughout this volume, are thus among the earliest examples anywhere of digital computer programs" (Ceruzzi 1985, xv-xvii).

The Mark I was an electromechanical machine, based largely on existing IBM punched-card technology. Paul Ceruzzi, in his introduction to the 1985 reprint of the Mark I's manual, described it as follows:

"The architecture of the Mark I was unlike that of any modern computer. Its basic units were a set of seventy-two accumulators that could both store and add 23-digit signed decimal numbers. There was no clear separation of the storage and arithmetic functions. Besides the accumulators there were sixty constant registers whose contents could be read but not altered during a program run, a multiply-divide unit, and paper tape readers for reading numbers and sequences of operations. . . ."  

"The basic computing element of the Mark I was a multipole rotary switch, connected by a clutch to a drive shaft, by which decimal units, carry, and timing information were stored. Banks of twenty-four switches (holding twenty-three decimal digits and the sign of a number), made up one accumulator. The drive shaft rotated continuously; electrically activated clutches engaged the wheels of an accumulator whenever a number was to be transferred. The clutches were in turn driven by double-throw relays. The Mark I was an electromechanical calculator: it held numbers in mechanical elements (the rotary switches), which were electrically controlled (by the clutch relays). Electrical pulses traveling along a common bus conveyed numbers to and from the accumulators. . . . Getting the Mark I to execute a desired sequence of operations involved a combination of two processes: preparing a sequence tape fed into the Sequence Control Unit (coding) and plugging cables into plugboards located at several places on the machine (setup). . . . The Sequence Tape reader had no provision for backing up the tape or for skipping steps. This meant that the Mark I executed only simple, linear sequences of instructions. Sequence (and Value) tapes could be cemented into endless loops, however, and this was frequently done. After 1947 a Subsidiary Sequence mechanism was attached to the Calculator that allowed such endless loops of tape to supply sub-sequences to the main sequence control (Ceruzzi 1985, xxi-xxvi).

After the Mark I was set up at Harvard in 1944 it was immediately commandeered for war work by the United States Navy. Aiken, a commander in the United States Naval Reserve (USNR), was put in charge of the navy's computation project, and he later joked that he was first naval officer ever to command a computer. Most of Aiken's staff at the Computation Laboratory also held commissions in the USNR. One of these was Lieutenant (later Admiral) Grace M. Hopper, a mathematician who, in her own words, had "never met a digit" until joining the Computation Laboratory (quoted in Ceruzzi 1985, xviii); she would go on to become one of the most famous of the postwar computer pioneers, making fundamental contributions to the development of the first compilers.  

The operating manual for the Mark I calculator - published as Volume 1 of the Annals of the Computation Laboratory of Harvard University - was written largely by Hopper, who was the chief author of chapters 1-3 and the eight appendices following chapter 6. Chapters 4 and 5 were written by Aiken and Robert Campbell, and chapter 6, containing directions for solving sample problems on the machine, was primarily the work of Brooks J. Lockhart.

Hook & Norman, Origins of Cyberspace, no. 411 and other entries.

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Highlights of Alan Turing and Colleagues' Cryptanalysis Work at Bletchley Park Circa September 1939 – 1945

On September 1, 1939 Germany invaded Poland, beginning World War II. Two days later, on September 3, Britain and France declared war on Germany. The following day Alan Turing appeared for work at the Code Code and Cypher School at Bletchley, England, with the goal of deciphering military communications encoded by means of Enigma machines.

As early as December 1932 the Biuro Szyfrów ("Cipher Bureau") in Warsaw, the Polish interwaragency charged with both cryptography  and cryptanalysis, had broken the German Enigma machine cipher.Over the next nearly seven years before World War II, the Polish "Cipher Bureau" overcame the growing structural and operating complexities of the plugboard-equipped Enigma, the main German cipher device during the Second World War.

Prior to the beginning of World War II, in October 1938 Polish Cipher Bureau mathematician and cryptologist Marian Rejewski designed the bomba, or bomba kryptologiczna  ("bomb" or "cryptologic bomb,") a special-purpose machine for breaking German Enigma machine  ciphers. On July 25, 1939 the Biuro Szyfrów revealed Poland's Enigma-decryption techniques and equipment, which it had achieved using the bomba device, to the French and British. Poland thereby made possible the western Allies' vitally important decryption of Nazi German   secret communications (Ultra) during World War II.

"Up to July 25, 1939, the Poles had been breaking Enigma messages for over six and a half years without telling their  French  and British allies. On December 15, 1938, two new rotors, IV and V, were introduced (three of the now five rotors being selected for use in the machine at a time). As Rejewski wrote in a 1979 critique of appendix 1, volume 1 (1979), of the official history of British Intelligence in the Second World War, 'we quickly found the [wirings] within the [new rotors], but [their] introduction [...] raised the number of possible sequences of drums from 6 to 60 [...] and hence also raised tenfold the work of finding the keys. Thus the change was not qualitative but quantitative. We would have had to markedly increase the personnel to operate the bombs, to produce the perforated sheets (60 series of 26 sheets each were now needed, whereas up to the meeting on July 25, 1939, we had only two such series ready) and to manipulate the sheets.'

"Harry Hinsley suggested in British Intelligence . . . that the Poles decided to share their Enigma-breaking techniques and equipment with the French and British in July 1939 because they had encountered insuperable technical difficulties. Rejewski refuted this: 'No, it was not [cryptologic] difficulties [. . .] that prompted us to work with the British and French, but only the deteriorating political situation. If we had had no difficulties at all we would still, or even the more so, have shared our achievements with our allies as our contribution to the struggle against Germany' ' (Wikipedia article on Bomba (cryptography), accessed 12-21-2008).

In the first few months after arriving at Bletchley Turing made a key deduction that led to his development of Banburismus, a cryptanalytic process used by Turing and his co-workers at Bletchley's Hut 8 to help break German Kriegsmarine (Naval) messages enciphered by Enigma.

"The process used sequential conditional probability to infer information about the likely settings of the Enigma machine. It gave rise to Turing's invention of the ban as a measure of the weight of evidence in favour of a hypothesis. This concept was later applied in Turingery and all the other methods used for breaking the Lorenz cipher.

"The aim of Banburismus was to reduce the time required of the electromechanical Bombe machines by identifying the most likely right-hand and middle wheels of the Enigma. Hut 8 performed the procedure continuously for two years, stopping only in 1943 when sufficient bombe time became readily available. Banburismus was a development of the "clock method" invented by the Polish cryptanalyst Jerzy Różyck

To develop Banburismus Turing

"deduced that the message-settings of Kriegsmarine Enigma signals were enciphered on a common G rundstellung (starting position of the rotors), and were then super-enciphered with a bigram and a trigram lookup table. These trigram tables were in a book called the Kenngruppenbuch (K book). However, without the bigram tables, Hut 8 were unable to start attacking the traffic. A breakthrough was achieved after the Narvik pinch in which the disguised armed trawler Polares, which was on its way to Narvik in Norway, was seized by HMS Griffin in the North Sea on 26 April 1940. The Germans did not have time to destroy all their cryptographic documents, and the captured material revealed the precise form of the indicating system, supplied the plugboard connections and Grundstellung for April 23 and 24 and the operators' log, which gave a long stretch of paired plaintext and enciphered message for the 25th and 26th.

"The bigram tables themselves were not part of the capture, but Hut 8 were able to use the settings-lists to read retrospectively, all the Kriegsmarine traffic that had been intercepted from 22 to 27 April. This allowed them do a partial reconstruction of the bigram tables and start the first attempt to use Banburismus to attack Kriegsmarine traffic, from 30 April onwards. Eligible days were those where at least 200 messages were received and for which the partial bigram-tables deciphered the indicators. The first day to be broken was 8 May 1940, thereafter celebrated as "Foss's Day" in honour of Hugh Foss, the cryptanalyst who achieved the feat.

"This task took until November that year, by which time the intelligence was very out of date, but it did show that Banburismus could work. It also allowed much more of the bigram tables to be reconstructed, which in turn allowed April 14 and June 26 to be broken. However, the Kriegsmarine had changed the bigram tables on 1 July. By the end of 1940, much of the theory of the Banburismus scoring system had been worked out.

"The First Lofoten pinch from the trawler Krebs on 3 March 1941 provided the complete keys for February - but no bigram tables or K book. The consequent decrypts allowed the statistical scoring system to be refined so that Banburismus could become the standard procedure against Kriegsmarine Enigma until mid-1943" (This and the earlier quotation are from the Wikipedia article on Banburismus, accessed 01-04-2015.)

About December 1940 Alan Turing and Gordon Welchman at Bletchley Park designed an improved Bombe cryptanalysis machine for deciphering Enigma messages.

Between 1940 and 1941 Max Newman and his team at Bletchley, including Turing, created the top-secret Heath Robinson cryptographic computer named after the cartoonist-designer of fantastic machines. This special-purpose relay computer successfully decoded messages encrypted by Enigma, the Nazis' first-generation enciphering machine.

In July 1942 Turing developed  the hand codebreaking method known as Turingery or Turing's Method (playfully dubbed Turingismus by Peter Ericsson, Peter Hilton and Donald Michie)  for use in cryptanalysis of the Lorenz cipher produced by the SZ40 and SZ42 teleprinter rotor stream cipher machines, one of the GermansGeheimschreiber (secret writer) machines. The British codenamed non-Morse traffic "Fish", and that from this machine "Tunny".

"Reading a Tunny message required firstly that the logical structure of the system was known, secondly that the periodically changed pattern of active cams on the wheels was derived, and thirdly that the starting positions of the scrambler wheels for this message—the message key—was established.The logical structure of Tunny had been worked out by William Tutte and colleagues over several months ending in January 1942. Deriving the message key was called "setting" at Bletchley Park, but it was the derivation of the cam patterns—which was known as "wheel breaking"—that was the target of Turingery.

"German operator errors in transmitting more than one message with the same key, producing a "depth", allowed the derivation of that key. Turingery was applied to such a key stream to derive the cam settings" (Wikipedia article on Turingery, accessed 01-04-2015).

In 1943 Alan Turing traveled to New York to consult with Claude Shannon and Harry Nyquist at Bell Labs concerning the encryption of speech signals between Roosevelt and Churchill.

In January 1944 the top-secret Colossus programmable cryptanalysis machine designed by Tommy Flowers and his team at the Post Office Research Station, Dollis Hill, in North West London, was installed at Bletchley Park to crack the higher level encryption of the Nazi Lorenz SZ40 machine. Colossus employed vacuum tubes and was between one hundred and one thousand times faster than Heath Robinson. "It exceeded all expectations and was able to derive many of the Lorenz settings for each message within a few hours, compared to weeks previously" (http://googleblog.blogspot.com/2012/03/remembering-colossus-worlds-first.html, accessed 03-0-2012). The Colossus machines have been called the first operational programmable electronic digital computers.

On June 1, 1944 the first improved Colossus Mark 2 with 2400 vacuum tubes was operational at Bletchley Park just in time for the Normandy Landings. By the end of the war there were ten Colossus computers operating. They enabled the decryption of 63,000,000 characters of high-grade German messages. Even though these machines incorporated features of special purpose electronic digital computers, and had incalculable influence on the outcome of WWII, they had little influence in the conventional sense on the development of computing technology because they remained top secret until about 1970.

"The Colossus computers were used to help decipher teleprinter  messages which had been encrypted using the Lorenz SZ40/42 machine — British codebreakers referred to encrypted German teleprinter traffic as "Fish" and called the SZ40/42 machine and its traffic as 'Tunny'. Colossus compared two data streams, counting each match based on a programmable Boolean function. The encrypted message was read at high speed from a paper tape. The other stream was generated internally, and was an electronic simulation of the Lorenz machine at various trial settings. If the match count for a setting was above a certain threshold, it would be sent as output to an electric typewriter" (Wikipedia article on Colossus computer, accessed 11-23-2008).

In March 2012 the Colossus Rebuild Project at the National Museum of Computing at Bletchley Park had completed an operating reconstruction of a Colossus II, after 10 years and over 6,000 man-days of volunteer effort. The Rebuild stands in its historically correct place, the room in H Block, in Bletchley Park, where Colossus No. 9 stood in WW II.

(This entry was last revised on 01-17-2015.)

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1940 – 1950

NIMATRON: An Early Electromechanical Machine to Play the Game of Nim 1940

For the Westinghouse Pavilion at the New York World's Fair in 1940 nuclear physicist Edward Condon, then associate director of research at the Westinghouse Electric Company in Pittsburgh, designed and patented an electromechanical machine called the Nimatron to play the ancient mathematical strategy game of Nim. Condon and associates applied for a patent on this early special purpose electromechanical computer in April 1940, after which the machine was displayed at the World's Fair. They received U.S. patent 2,215,544 for "Machine to Play Game of Nim" on September 24, 1940. The first two images of the machine reproduced with the patent presumably show the machine as it was built. Other drawings in the machine are logic diagrams. The machine played 100,000 games at the fair, winning about 90,000. Most of its defeats were apparently administered by attendants to demonstrate that possibility. When the machine did lose it would "present its opponent with a token coin stamped with the words 'Nim Champ' "

In 1939 Westinghouse produced a 55 minute promotional film illustrating "the contribution of free enterprise, technology, and Westinghouse products to the American way of life." Entitled The Middleton Family at the New York World's Fair, it may be viewed here: 

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The Design and Principles of John Atanasoff's ABC Machine, and What John Mauchly Knew About It August – December 1940

In August 1940 American physicist and inventor John Atanasoff at Iowa State University in Ames, Iowa, wrote a thirty-five-page memorandum describing the design and principles of the what came to be known as the Atanasoff-Berry Computer or ABC machine. This may be the earliest extant document describing the principles of an electronic digital computer. It remained unpublished until 1973.

In December 1940 John Mauchly met Atanasoff at the Philadelphia meeting of the American Association of the Advancement of Science. After corresponding with Atanasoff about electronic calculating, Mauchly visited Atanasoff in Ames, and read the 35-page memorandum on the ABC machine that Atanasoff had written in August. Mauchly would later incorporate some of Atanasoff's ideas into his design for the ENIAC.

Because of World War II, in 1942 Atanasoff abandoned work on his special purpose ABC machine when it was nearly operational. The machine was largely forgotten until interest in it was revived for the lawsuit over the ENIAC patent. As a reference on Atanasoff and the ENIAC patent case I recommend the Iowa State University Department of Computer Science website on Atanasoff. In December 2014 it was available at this link.

(This entry was last revised on 12-31-2014.)

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Key Events in the Development of the First General Purpose Electronic Digital Computer, the ENIAC June 1941 – October 2, 1955

In June 1941 J. Presper Eckert and John Mauchly met at the Moore School of Electrical Engineering, now part of the University of Pennsylvania School of Engineering and Applied Science, and began discussions on electronic computing. In August 1942 Mauchly wrote a privately circulated confidential memorandum on “The Use of High Speed Vacuum Tube Devices for Calculating.” This was after he had visited John Atanasoff in Iowa.

With the goal of speeding up the calculation of artillery firing tables, on April 8, 1943  Eckert and Mauchly submitted a proposal to the Ballistic Research Laboratory at Aberdeen Proving Ground, near Aberdeen, Maryland. Their proposal was entitled Report on an Electronic Difference Analyzer. By calling their proposed device an electronic difference analyzer Eckert and Mauchly tried to make the distinction between the electromechanical analog differential analyzer that the United States Army was using and the new electronic digital machine that would be developed. The proposal was submitted to army ordnance in May.

When the first contracts were signed between the U. S. Army and the Moore School, the name of the machine was changed to Electronic Numerical Integrator. Because Mauchly stressed that the machine could be used for more general problems, the device was called an “Electronic Numerical Integrator and Computer (ENIAC).” Eckert was appointed laboratory supervisor and chief engineer on the project. Mauchly, along with Eckert, was put in charge of engineering and testing. On May 31, 1943 construction of the ENIAC started at the Moore School. The actual contract between the Moore School and the army did not go into effect until July 1. For security reasons, the understandable rumor that the project was a “white elephant” was promoted rather than denied.

In July 1944 Eckert had two accumulators of the ENIAC operational.

About May 1945 the ENIAC was completed and tested at the Moore School. With eighteen thousand vacuum tubes and weighing thirty tons, the ENIAC was about one thousand times faster than the Harvard Mark I, and 10,000 times the speed of a human computer doing a calculation. Programming the ENIAC was accomplished by time-consuming plugging of patch cords from buses to panels for each individual problem.

On November 30, 1945 Eckert, Mauchly, John Brainerd, and Herman Goldstine issued the first confidential published report on the completed ENIAC, discussing how it operated and the methods by which it was programmed: Description of the ENIAC and Comments on Electronic Digital Computing Machines.The report was published under the auspices of theApplied Mathematics Panel, National Defense Research Committee. In the spring of 1945 the National Defense Research Committee (NDRC) was becoming very interested in electronic computers, and mathematician Warren Weaver, head of the NDRC’s Applied Mathematics Panel, asked John von Neumann to write a report on the Moore School’s ENIAC and EDVAC projects. Von Neumann was unable to fulfill Weaver’s request, so Weaver assigned the task to John Grist Brainerd, director of the ENIAC project. Brainerd was eager to have the report appear under his name, but Eckert and Mauchly objected, since Brainerd was largely unfamiliar with the scientific aspects of the project. After some internal dispute, it was agreed that the report’s authors should be listed on the title as Eckert, Mauchly, Goldstine, and Brainerd. The report was issued with a “Restricted” classification and 91 copies were distributed to military, Office of Scientific Research and Development and NDRC personnel, as indicated by the distribution list on the inside front cover.

Although confidential progress reports on ENIAC had been issued in 1944, this report of November 30, 1945, was the first account of the completed machine. As stated in the title, the report contained a detailed description of ENIAC, the world’s first large-scale electronic general-purpose digital computer, as well as chapters on the need for high-speed computing machines, the advantages of electronic digital machines, design principles for high-speed computing machines, and reliability and checking. At the end are three appendices discussing ENIAC’s arithmetic operations, programming methods, and general construction data. This may have been the earliest published report on how the first electronic digital computer was programmed. Even though the ENIAC was not a stored-program computer its design and mode of operation involved numerous programming firsts The report also provided information on the planned stored-program EDVAC, which was then in an early design stage. For the three years between May 1945 and June 1948, ENIAC remained the only functioning electronic, general purpose digital computer in the world until the short-lived Manchester “Baby” prototype became operational in 1948.

 On February 14, 1946 the ENIAC was publicly unveiled in Philadelphia.

On July 15, 1946 Eckert lectured at the Moore School on “A preview of a digital computing machine.” He proposed replacing the three different kinds of memory used in the ENIAC (flip-flops in accumulators, function tables [read-only memory] and interconnecting cables with switches) with a single erasable high-speed memory—the mercury delay-line memory that he invented for this purpose. This was a key step in the development of a stored-program computer. In 1947 the ENIAC was converted into an elementary stored-program computer by the use of function tables. 

At 11:45 p.m. on October 2, 1955, after roughly ten years of continuous service, power to the ENIAC was disconnected for the last time at the Aberdeen Proving Ground, and the machine was retired. It was estimated that this single machine did more computation during the ten years of its operation than the entire human race had done up till the time of its invention.

Hook & Norman, Origins of Cyberspace (2002) No. 1107 and other entries.

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IBM's Vacuum Tube Multiplier, the First Complete Machine to Perform Arithmetic Electronically 1943

In 1943 IBM at Endicott, New York developed the Vacuum Tube Multiplier. This was first complete machine to perform arithmetic electronically. By substituting vacuum tubes for electro-mechanical relays it could process information thousands of times faster than electro-mechanical calculators.

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Key Developments in Jay W. Forrester's Project Whirlwind 1943

In 1943 Project Whirlwind began as an analog flight simulator project at MIT. About November 1945 the project switched from analog to digital electronics. Formal design of the machine began in 1947.

By 1950 Project Whirlwind was in limited operation at MIT as a general purpose computer. It was the first computer that operated in real time, with the first video display for output, and it was the first computer that was not just an electronic replacement of older mechanical systems. On April 20, 1951 Whirlwind offically began operation at MIT. Whirlwind I included the first primitive graphical display on its vectorscope screen.

In 1952 three-dimensional magnetic-core memory replaced electrostatic memory on the Whirlwind I, leading to increased performance and reliability. 

In 1954 programmers J. H. Laning and Neil Zierler developed an algebraic compiler for theWhirlwind I—the first high-level algebraic language for a computer.

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MTAC: The First Computing Journal 1943 – 1960

In 1943 Mathematical Tables and Other Aids to Computation (MTAC), the world’s first computing journal, began publication in Washington, D.C. At this time mathematical tables prepared by human computers were the primary calculating aid. The journal reported new mathematical tables, and on the new electromechanical and electronic “aids to computation” as they were developed.

By 1960, reflecting the obsolescence of mathematical tables as a result of the development of electronic computing, MTAC changed its name to Mathematics of Computation.

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The Bell Labs Relay Interpolator, Possibly the First Electromechanical Computer to Run Programs in the U.S. September 1943

In September 1943 the Bell Labs Relay Interpolator (later called the Model II) was operational for the first time. Using programs from punched tape, the Relay Interpolator, which used 440 relays, was possibly the first electromechanical computer to run programs in the United States. 

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Key Developments Concerning the ENIAC Patent, the Patent on the General Purpose Electronic Digital Computer January 29, 1944 – October 19, 1973

On January 29, 1944, while Pres Eckert and John Mauchly were working on making the ENIAC operational at the Moore School at the University of Pennsylvania, Eckert wrote a three-page typewritten document entitled Disclosure of Magnetic Calculating Machine. This confidential document, which was not formally published until decades after it was written, very briefly and generally described a theoretical electronic computer that would store its program and data in an electronic memory— a type of magnetic disc or drum. Years later the document was unearthed in the trial over the ENIAC patent, to show that Eckert had conceived elements of the stored program concept before John von Neumann wrote down and distributed a complete theoretical description of a stored-program computer in his First Draft of a Report on the EDVAC

Mostly likely von Neumann and Eckert and Mauchly developed the stored-program computer concept jointly— Eckert from the engineering side and von Neumann from the theoretical side. Because von Neumann first described the design of the stored-program computer, its architecture has come to be known as the von Neumann architecture. In October 2013 I viewed the copy of Eckert's disclosure posted on the website of the Computer History Museum. This copy included an informative cover letter sent by John Mauchly to Donald Knuth on June 22, 1978.

About eight months after Eckert's "Disclosure," on September 27, 1944 Eckert and Mauchly declared that their conception of the ENIAC was complete. Eckert wrote a letter to other members of the project asking them to state written claims to inventions on the project. None was received. Also in September 1944, faced with mathematical computations regarding the Atomic bomb that were impossible for human computers, mathematician and physicist John von Neumann visited the ENIAC two-accumulator system for the first time, well before the computer was operational, and became deeply interested in the project. This visit represented the beginning of von Neumann's interest in electronic computing. As a result of his research, on June 30, 1945 von Neumann privately circulated copies of his First Draft on a Report on the EDVAC to twenty-four people connected with the EDVAC project. This document, written between February and June 1945, provided the first theoretical description of the basic details of a stored-program computer.

On April 8, 1947 Eckert and Mauchly learned from a patent lawyer that John von Neumann’s First Draft of a Report on the EDVAC was a publication barring their patenting the ENIAC because von Neumann's report, which described the theoretical principles of the machine, was issued more than a year before they planned to apply for a patent. Nevertheless, that knowledge did not, however, deter Eckert and Mauchly from applying for the patent. On June 26, 1947 Eckert and Mauchly applied for the broad ENIAC patent, essentially a patent on the stored-program electronic digital computer. They based their description of the machine to a large extent on the government report they issued on November 30, 1945.

While the ENIAC patent was being applied for, on August 21, 1956 Sperry Rand, to whom Eckert and Mauchly had transferred their patent rights, agreed to cross-license patents with IBM, thereby turning over strategic technology. On February 4, 1964 Eckert and Mauchly finally received U.S. patent no. 3,120,606 for the ENIAC—a general patent on the stored-program electronic computer, roughly 18 years after their application. Sperry Rand Univac, owner of the patent, charged a 1.5 percent royalty for all electronic computers sold by all companies except IBM, with which it had previously cross-licensed patents. Since IBM manufactured the majority of computers produced at this time, the royalties on the patent were not as large as they could have been.

On October 19, 1973 Eckert and Mauchly’s ENIAC patent was ruled invalid in the case of Honeywell Inc. v. Sperry Rand Corporation et al, largely because of John von Neumann's prior theoretical description of the machine that was circulated in his First Draft of a Report on the EDVAC. and evidence that John Mauchly obtained some of his key ideas for the design of the ENIAC from John Atanasoff's report of 1940.

Norman, From Gutenberg to the Internet, 

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Von Neumann Privately Circulates the First Theoretical Description of a Stored-Program Computer June 30, 1945

On June 30, 1945 mathematician and physicist John von Neumann of Princeton privately circulated copies of his First Draft on a Report on the EDVAC to twenty-four people connected with the EDVAC project. This document, written between February and June 1945, provided the first theoretical description of the basic details of a stored-program computer—what later became known as the Von Neumann architecture.

To avoid the government's security classification, and to avoid engineering problems that might detract from the logical considerations under discussion, von Neumann avoided mentioning specific hardware. Influenced by Alan Turing and by Warren McCulloch and Walter Pitts, von Neumann patterned the machine to some degree after human thought processes.

In November 2013 the text of von Neumann's report was available at this link

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The First Engineering Report on the EDVAC September 30, 1945

On September 30, 1945 J. Presber Eckert and John Mauchly published Automatic High-Speed Computing. A Progress Report on the EDVAC.  Parts 5,6, and 7 of the report were written by Harry Huskey. This report, written from the engineering point of view, was the first detailed report on the EDVAC published after John von Neumann's theoretical First Draft of the Report on the EDVAC, which had been published on June 30, 1945. 

In their Acknowledgments to the report published by the Moore School at the University of Pennsylvania Eckert & Mauchly credited Arthur Burks, Herman Goldstine and "especially Dr. John von Neumann" for their participation in "discussions of EDVAC plans." Eckert and Mauchly's confidential report was issued in only 50 copies.

Notably in the "Historical Comments" beginning the report Eckert and Mauchly referred to Eckert's unpublished 1944 memorandum, Disclosure of Magnetic Calculating Machine, and indicated that they planned to use the delay line memory that Eckert had recently invented instead of any type of magnetic disk or drum to which the 1944 "disclosure" alluded. When Eckert and Mauchly left the Moore School to start their own business, the Electronic Control Company, to commercialize electronic computers, they used Eckert's delay line memories on their first products, the BINAC and the UNIVAC.

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Turing's Main Hardware Design After World War II, the Automatic Computing Engine (ACE) Circa October 1945 – February 20, 1947

About October 1945 Alan Turing arrived at the National Physical Laboratory,Teddington, England, to work on the Automatic Computing Engine (ACE). There Turing prepared a typed proposal, “Proposed electronic calculator,” outlining the development of the ACE. In February 2012 Turing's report could be read at the Turing Digital Archive, at this link: http://www.turingarchive.org/browse.php/C/32.

In a lecture on February 20, 1947 to the London Mathematical Society that remained unpublished until 1986 Turing stated that “digital computing machines such as the ACE. . . are in fact practical versions of the universal machine,” i.e. the Turing machine.

(This entry was last revised on 12-31-2014.)

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Key Developments in von Neumann's IAS Electronic Computer Project March 1946 – 1947

In March 1946 John von Neumann attempted to set up an electronic stored-program computer project at the Institute for Advanced Study (IAS) at Princeton. He tried to hire Pres Eckert, but Eckert refused the job, preferring to go into the computer business with John Mauchly as the Electronic Control Company.

In June 1946 engineer Julian Bigelow, who previously had collaborated with Norbert Wiener at MIT, joined von Neumann and Herman Goldstine at the Princeton IAS Electronic Computer Project. He was to a large extent responsible for implementing von Neumann's stored-program concepts.

At Princeton in June 1946 Arthur W. Burks, von Neumann, and Goldstine issued their Preliminary Discussion of the Logical Design of an Electronic Computing Instrument, discussing ideas to be incorporated into the stored-program computer at the IAS.

Around June 1947 Julian Bigelow and his team at Princeton redesigned the IAS machine to include error checking and parallel processing, essential features of what became known as the von Neumann architecture.

(This entry was last revised on 01-01-2015.)

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The Moore School Lectures Take Place July 8 – 1946

From July 8 to August 30, 1946 the Moore School lectures on “The theory and techniques for design of electronic digital computers” occurred at the University of Pennsylvania. This series of lectures, attended by twenty-eight highly qualified experts, led to widespread adoption of the EDVAC-type design—including stored programs—for nearly all subsequent computer development. 

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A Soroban Beats an Electric Calculator November 12, 1946

On November 12, 1946  contest was held in Tokyo between the Japanese soroban, used by Kiyoshi Matsuzaki, a champion operator in the Savings Bureau of the Japanese postal administration, and an electric calculator, operated by US Army Private Thomas Nathan Wood of the 240th Finance Distributing Section of General MacArthur's headquarters. Wood was the most experienced calculator operator in Japan at the time. The bases for scoring in the contest were speed and accuracy of results in all four basic arithmetic operations, and a problem which combined all four. The soroban won 4 to 1, with the electric calculator prevailing in multiplication.

"About the event, the Nippon Times newspaper reported that "Civilization ... tottered" that day, while the Stars and Stripes newspaper described the soroban's "decisive" victory as an event in which "the machine age took a step backward. . . ."

"The breakdown of results is as follows:

"* Five additions problems for each heat, each problem consisting of 50 three- to six-digit numbers. The soroban won in two successive heats.

"* Five subtraction problems for each heat, each problem having six- to eight-digit minuends and subtrahends. The soroban won in the first and third heats; the second heat was a no contest.

"* Five multiplication problems, each problem having five- to 12-digit factors. The calculator won in the first and third heats; the soroban won on the second.

"* Five division problems, each problem having five- to 12-digit dividends and divisors. The soroban won in the first and third heats; the calculator won on the second.

"* A composite problem which the soroban answered correctly and won on this round. It consisted of:

"o An addition problem involving 30 six-digit numbers

"o Three subtraction problems, each with two six-digit numbers o Three multiplication problems, each with two figures containing a total of five to twelve digits

"o Three division problems, each with two figures containing a total of five to twelve digits" (Wikipedia article on Soroban, accessed 04-15-2009). 

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Couffignal Decides against Building a Stored-Program Computer in France 1947

In 1947 French mathematician Louis Couffignal and French-American physicist Leon Brillouin held a small conference on “large computers” in Paris, at which Couffignal discussed French work, and Brillouin summarized American accomplishments in electronic digital computing.

Having researched computing theory as early as 1942, when he delivered a lecture to the Comité National de l'Organisation Française on the future of computingCouffignal decided against building a stored-program computer. This mistake caused France to fall behind England and America in computing technology. The government agency where Couffignal worked, Centre National de la Recherche Scientifique (CNRS), did not obtain a stored-program computer (a British model) until 1955. Only in 1956 was the first stored-program computer manufactured in France.

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Kurt Herzstark Invents the Curta, the Most Advanced Small Mechanical Calculator 1947

In 1947 Contina Ltd of Vaduz, Liechtenstein began production of the Curta Model 1 pocket mechanical calculator. The most advanced small mechanical calculator ever built, the Curta was designed by Curt Hertzstark, a calculating machine manufacturer, while he was a prisoner in Buchenwald concentration camp from 1943 to 1945. The Nazis operating the concentration camp encouraged Hertzstark to complete the design while he was in Buchenwald, and produced a prototype by the end of the war. The Curta calculator was manufactured until 1973.

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Key Events in the Development of the UNIVAC, the First Electronic Computer Widely Sold in the United States April 24, 1947 – November 4, 1952

On April 24, 1947 the Electronic Control Company (Pres Eckert and John Mauchly) in Philadelphia developed the tentative instruction code C-1 for what they called  “a Statistical EDVAC.” This was the earliest document on the programming of an electronic digital computer intended for commercial use. On May 24, 1947 they renamed the planned “Statistical EDVAC” the UNIVAC. About November 1947 Electronic Control Company  issued the first brochure advertising the UNIVAC —the first sales brochure ever issued for an electronic digital computer. A special characteristic of the brochure was that it did not show the product, since at this time the product was not yet fully conceptualized either in design or external appearance. 

On October 31, 1947 Eckert and Mauchly applied for a U.S. patent on the mercury acoustic delay-line electronic memory system. This was the "first device to gain widespread acceptance as a reliable computer memory system." (Hook & Norman, Origins of Cyberspace [2002]1191).  The patent 2,629,827 was granted in 1953.

In 1948 a contract was drawn up between the renamed company, Eckert-Mauchly Computer Corporation, and the United States Census Bureau for the production of the UNIVAC. On October 31, 1947 Pres Eckert and John Mauchly of Philadelphia applied for a U.S. patent on the mercury acoustic delay-line electronic memory system. This was the "first device to gain widespread acceptance as a reliable computer memory system." (Hook & Norman, Origins of Cyberspace [2002]1191). The patent 2,629,827 was granted in 1953.

As the first UNIVAC was being developed, in 1949 Betty Holbertson  developed the UNIVAC Instructions Code C-10. C-10 was the first software to allow a computer to be operated by keyboarded commands rather than dials and switches. It was also the first mnemonic code. Also in 1949, Grace Hopper left the Harvard Computation Laboratory to join Eckert-Mauchly Computer Corporation as a senior mathematician/programmer. In June 1949 John Mauchly conceived the Short Code—the first high-level programming language for an electronic computer—to be used with the BINAC. It was also the first interpreted language and the first assembly language. The Short Code first ran on UNIVAC I, serial 1, in 1950. [In 2005 no copies of the Short Code existed with dates earlier than 1952.]

UNIVAC I, serial 1, was signed over to the United States Census Bureau on March 31, 1951. The official dedication of the machine at the government offices occurred on June 14, 1951. Excluding the unique BINAC, the UNIVAC I was the first electronic computer to be commercially manufactured in the United States. Its development preceded the British Ferranti Mark 1; however, the British machine was actually delivered to its first customer one month earlier than the UNIVAC I.

Though the United States Census Bureau owned UNIVAC I, serial 1, the Eckert-Mauchly division of Remington Rand retained it in Philadelphia for sales demonstration purposes, and did not actually install it at government offices until twenty-one months later.

In 1951 magnetic tape was used to record computer data on the  UNIVAC I with its UNISERVO tape drive. The UNISERVO was the first the tape drive for a commercially sold computer.

It's "recording medium was a thin metal strip of ½″ wide(12.7 mm) nickel-plated phosphor bronze. Recording density was 128 characters per inch (198 micrometre/character) on eight tracks at a linear speed of 100 in/s (2.54 m/s), yielding a data rate of 12,800 characters per second. Of the eight tracks, six were data, one was a parity track, and one was a clock, or timing track. Making allowance for the empty space between tape blocks, the actual transfer rate was around 7,200 characters per second. A small reel of mylar tape provided separation from the metal tape and the read/write head" (Wikipedia article on Univac I, accessed 04-26-2009).

In 1952 Grace Hopper wrote the first compiler (A-0) for UNIVAC, and on October 24, 1952 he UNIVAC Short Code II was developed. This was the earliest extant version of a high-level programming language actually intended to be used on an electronic digital computer.

On November 4, 1952 UNIVAC I, serial 5, used by the CBS television network in New York City, successfully predicted the election of Dwight D. Eisenhower as president of the United States. This was the first time that millions of people (including me, then aged 7) saw and heard about an electronic computer. The computer, far too large and delicate to be moved, was actually in Eckert-Mauchly's corporate office in Philadelphia. What was televised by Walter Cronkite from CBS studios in New York was a dummy terminal connected by teletype to the machine in Philadelphia.

Univac 1, serial 5 was later installed at Lawrence Livermore Laboratories in Livermore, California.

♦ In 2010 journalist Ira Chinoy completed a dissertation on journalists' early encounters with computers as tools for news reporting, focusing on election-night forecasting in 1952. The dissertation, which also explored methods journalists used to cover elections in the age of print, was entitled Battle of the Brains: Election-Night Forecasting at the Dawn of the Computer Age.

In 1954 UNIVAC I, serial 8, was installed at General Electric Appliance Park, Louisville, Kentucky. Serial 8 was the first stored-program electronic computer sold to a nongovernmental customer in the United States. It ran the "first successful industrial payroll application."

This humorous promotional film for the Remington Rand UNIVAC computer features J. Presper Eckert and John Mauchly in leading roles. Produced in 1960, the film outlines the earlier history of computing leading to the development and application of the UNIVAC.

(This entry was last revised on 12-31-2014.)
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Innovative Aspects of the BINAC, the First Electronic Computer Ever Sold October 1947 – September 1950

In October 1947 Northrop Aircraft, Inc. of Hawthorne, California, ordered the BINAC (BINary Automatic Computer) from Pres Eckert and John Mauchly’s Electronic Control Company in Philadelphia. The BINAC consisted of two identical serial computers operating in parallel, with mercury delay-line memories, and magnetic tape as secondary memories and auxiliary input devices.

On September 9, 1948 the second module of the BINAC was completed in Philadelphia. Among its numerous innovations were germanium diodes in the logic processing hardware—probably the first application of semiconductors in computers. Until its delivery to Northrop Aircraft in September 1949, the BINAC remained in Philadelphia for use in numerous sales demonstrations.

In February 1949 Albert A. Auerbach, one of the designers of the BINAC CPU at Pres Eckert and John Mauchly's Electronic Control Company, ran a small test routine for filling memory from the A register. This was the first program run on the first stored-program electronic computer produced in the United States. 

On August 22, 1949 Eckert-Mauchly Computer Corporation of Philadelphia issued a press release describing the sale of the BINAC. This was the first press release ever issued for the sale of an electronic computer.

In 2014 it was my privilege and pleasure to handle the only known copy of the first manual ever written for a functioning electronic computer: the Operating and Maintenance Manual for the BINAC Binary Automatic Computer Built for Northrop Aircraft CorporationThis 37-page document, reproduced from typescript by Eckert-Mauchly Computer Corp. in Philadelphia in 1949, was the model for countless numbers of operating manuals for computers that were written in the following decades. As only one BINAC was ever built it is likely that only a handful of copies of the manual were ever produced.

Eckert and Mauchly’s BINAC was the first stored-program computer ever fully operational, since the Moore School’s EDVAC, which was designed to be the first stored-program computer, did not become operational until 1952. The BINAC was also the first stored-program computer that was ever sold.

The BINAC was extremely advanced from a design standpoint: It was a binary computer with two serial CPUs, each with its own 512-word acoustic delay line memory. The CPUs were designed to continuously compare results to check for errors caused by hardware failures. It used approximately 1500 vacuum tubes, making it virtually a mini-computer compared to its predecessor, the large-room-sized ENIAC, which used approximately 18,000 vacuum tubes. The two 512-word acoustic mercury delay line memories were divided into 16 channels each holding 32 words of 31bits, with an additional 11-bit space between words to allow for circuit delays in switching. The clock rate was 4.25 MHz (1 MHz according to one source) which yielded a word time of about 10 microseconds. The addition time was 800 microseconds and the multiplication time was 1200 microseconds. New programs or data had to be entered manually in octal using an eight-key keypad. BINAC was significant for being able to perform high-speed arithmetic on binary numbers, although it had no provisions for storing characters or decimal digits.

In 1946, after developing and building the ENIAC (the first general-purpose electronic computer) for the U. S. Army during World War II, J. Presper Eckert and John Mauchly founded their own company for the purpose of designing and manufacturing electronic stored-program computers on a commercial basis. In October 1947, needing money to keep their business afloat while working on their UNIVAC machine for the U.S. Census Bureau, Eckert and Mauchly entered into a contract with Northrop Aircraft to build the Binary Automatic Computer (BINAC). Northrop, based in Hawthorne, California, was then engaged in a project to build a long-range guided missile for the U.S. Air Force, and had the idea of using electronic computers for airborne navigation; the BINAC, while not designed to work in flight, would perhaps be an initial step toward that eventual goal. Airborne computers did not become feasible until the 1960s, when miniaturized solid-state transistorized components became available.

The BINAC was completed in August, 1949, $178,000 over budget; Eckert and Mauchly absorbed the loss themselves. Built with two serial processors, the BINAC functioned more like two computers than one, with the goal of providing a safety back-up for airplanes. Each part of the device was built as a pair of systems that would check each step. All instructions were carried out once by each unit, and then the result would be compared between the units. If they matched, the next instruction would be carried out; but if there was a discrepancy between the two parts of the machine, it stopped. The processors were only five feet tall, four feet long and a foot wide, tiny for those days. The machine could only do 3,500 additions per second compared to 5,000 on the ENIAC, but it could do 1,000 multiplications per second, compared to only 333 on the ENIAC.

Many histories of computing state that the BINAC never operated successfully; however, Northrop’s “Description of Northrop Computing Center,” an internal company document dated September 16, 1950, which I also handled in 2014, listed the BINAC as one of its three main pieces of computing equipment, and even though the machine was currently “being revised and improved for more reliable operation,” it was still functioning at least somewhat satisfactorily a year after its delivery.

"This machine has solved in seven minutes a problem on the effect of a certain wind pressure on a rubber diaphragm that would have occupied a mathematician for a year. It has solved Poisson’s Equation and obtained a network of 26 solutions in only two hours. For each of these solutions, the BINAC performed 500,000 additions, 200,000 multiplications, and 300,000 transfers of control, all in the space of five minutes. . . . This machine, which is a general purpose computer calculating in the binary system but receiving and emitting its instructions in the octal system, will be demonstrated today on a short test problem (“Description of Northrop Computing Center,” p. 2).

The task of writing the BINAC’s operating manual was assigned to Joseph D. Chapline, an EMCC employee who had helped Eckert and Mauchly on the ENIAC project at the Moore School. Realizing that the BINAC’s users at Northrop would not be electronic computer specialists, Chapline decided to model his BINAC guide on the owner’s manuals issued by automobile companies, rather than on the technical reports written for the Moore School’s ENIAC and EDVAC, which were intended for highly trained engineers and scientists already familiar with the respective machines. Chapline’s Operating and Maintenance Manual provided the BINAC user with a full overview of the machine’s construction, operations and maintenance in a step-by-step, readable manner, with clear diagrams illustrating the BINAC’s various components. Chapline’s instructional, user-oriented approach set the pattern for the millions of computer manuals that would follow it.

Chapline, who also wrote the documentation for the ENIAC, was a pioneer in the field of modern technical writing, which “translate[s] complex technical concepts and instructions into a series of comprehensible steps that enable users to perform a specific task in a specific way” (Wikipedia). Chapline taught over 200 classes in technical writing at the Moore School before leaving the computer profession in 1953 to become the organist and choirmaster at the Unitarian Church of Germantown in Philadelphia. Brockman, From Millwrights to Shipwrights to the Twenty-First Century, ch.7.

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First Assemblage of Digital Electronics Replaceable as a Unit 1948

In 1948 IBM produced the 604 Card-Programmed Electronic Calculator (CPC). Based on vacuum-tube technology, and programmed by making wired connections on a plugboard, the mass-produced CPC 604 featured the industry’s first assemblage of digital electronics replaceable as a unit.

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Andrew D. Booth Invents the First Magnetic Drum Memory 1948

In 1948 British electrical engineer, physicist and computer scientist Andrew D. Booth of Birkbeck College, London, created a magnetic drum memory, two inches long and two inches wide, and capable of holding 10 bits per square inch.

Booth offered his magnetic memory units for sale in 1952.

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IBM's SSEC, the First Computer that Can Modify a Stored Program January 1948

In January 1948 IBM announced its first large-scale digital calculating machine, the Selective Sequence Electronic Calculator (SSEC). The SSEC was the first computer that could modify a stored program. It featured 12,000 vacuum tubes and 21,000 electromechanical relays.

“IBM's Selective Sequence Electronic Calculator (SSEC), built at IBM's Endicott facility under the direction of Columbia Professor Wallace Eckert and his Watson Scientific Computing Laboratory staff in 1946-47, . . . was moved to the new IBM Headquarters Building at 590 Madison Avenue in Manhattan, where it occupied the periphery of a room 60 feet long and 30 feet wide. . . . [Estimates of the] dimensions of its "U" shape [were] at 60 + 40 + 80 feet, 180 feet in all, (about half a football field!)”

 "Designed, built, and placed in operation in only two years, the SSEC contained 21,400 relays and 12,500 vacuum tubes. It could operate indefinitely under control of its modifiable program. On the average, it performed 14-by-14 decimal multiplication in one-fiftieth of a second, division in one-thirtieth of a second, and addition or subtraction on nineteen-digit numbers in one-thirty-five-hundredth of second... For more than four years, the SSEC fulfilled the wish Watson had expressed at its dedication: that it would serve humanity by solving important problems of science. It enabled Wallace Eckert to publish a lunar ephemeris ... of greater accuracy than previously available... the source of data used in man's first landing on the moon". "For each position of the moon, the operations required for calculating and checking results totaled 11,000 additions and subtractions, 9,000 multiplications, and 2,000 table look-ups. Each equation to be solved required the evaluation of about 1,600 terms — altogether an impressive amount of arithmetic which the SSEC could polish off in seven minutes for the benefit of the spectators" (http://www.columbia.edu/acis/history/ssec.html#sources, accessed 03-24-2010).

The SSEC remained sufficiently influential in the popular view of mainframes that it was the subject of a cartoon by Charles Addams published on the cover of The New Yorker magazine in February 11, 1961, in which the massive machine produced a Valentine's Day card for its elderly woman operator!

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The Williams Tube and the "Manchester Baby," the First Operational Stored-Program Computer Runs its First Program June 21, 1948

In July 1946 mathematician Max Newman founded the computer laboratory at Manchester University via a grant from the Royal Society. Early on engineers in the department recognized that building an electronic memory would be the most difficult task in building a stored-program computer. In June 1946, English engineer F.C. (Freddie) Williams had begun research on the storage of both analog and digital information on a cathode ray tube at the Telecommunications Research Establishment. By November 1946 he was able to store a single bit (with the "anticipation" method), based around a standard radar CRT, and filed a provisional patent for the mechanism in December 1946.

"In December 1946 Freddie Williams was appointed to a chair at the University of Manchester, and left TRE. However both he and TRE wanted the research to continue, so Tom Kilburn, who was in his group at TRE, was seconded to the University of Manchester to continue the work with Freddie Williams on digital CRT storage. A Scientific Officer from TRE was also seconded full time to help him, initially Arthur Marsh, who left after a few months, and was replaced in the summer of 1947 by Geoff Tootill.

"By March 1947 Tom Kilburn had discovered a different and better method of storing information, more suited to storing a large number of bits on the same tube. By November 1947 they had succeeded in storing 2048 bits for a period of hours, having investigated a number of variations on storing a set of bits (dot-dash, dash-dot, defocus-focus, focus-defocus)" (http://www.computer50.org/mark1/new.baby.html#tootill, accessed 10-09-2011).

"The Williams tube tended to become unreliable with age, and most working installations had to be "tuned" by hand. By contrast, mercury delay line memory was slower and also needed hand tuning, but it did not age as badly and enjoyed some success in early digital electronic computing despite its data rate, weight, cost, thermal and toxicity problems. However, the Manchester Mark 1 was successfully commercialised as the Ferranti Mark 1. Some early computers in the USA also used the Williams tube, including the IAS machine, originally designed for Selectron tube memory, the UNIVAC 1103, IBM 701, IBM 702 and the Standards Western Automatic Computer (SWAC). Williams tubes were also used in the Soviet computer, Strela-1" (Wikipedia article on Williams Tube, accessed 10-09-2011).

After two years of research and development, on June 21, 1948 the Manchester Small Scale Experimental Machine,or  Manchester "Baby" prototype computer (Manchester Baby), ran its first program, written by Tom Kilburn. This small pilot version of a larger computer was the first stored-program electronic digital computer. It operated for only a short time.  The machine was built at the Victoria University of Manchester in England by Frederic C. Williams, Tom Kilburn and Geoff Tootill to test the Williams-Kilburn cathode ray tube (CRT) memory (Williams tube).

"The machine was not intended to be a practical computer but was instead designed as a testbed for the Williams tube, an early form of computer memory. Although considered 'small and primitive' by the standards of its time, it was the first working machine to contain all of the elements essential to a modern electronic computer. As soon as the SSEM 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 SSEM 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 218 (262,144), a calculation it was known would take a long time to run—and so prove the computer's reliability—by testing every integer from 218 − 1 downwards, as divisions had to be implemented by repeated subtractions of the divisor. The program consisted of 17 instructions and ran for 52 minutes before reaching the correct answer of 131,072, after the SSEM had performed 3.5 million operations (for an effective CPU speed of 1.1 kIPS)" (Wikipedia article Manchester Small Scale Experimental Machine, accessed 10-09-2011).

You can watch a streaming video of a 1948 BBC newsreel about the Manchester "Baby" at this link. [You will need to scroll down the web page.]

None of the original Manchester Baby exists; however, a working replica 5.2 meters long and 1 ton in weight is on display at the Manchester Museum of Science and Industry (MOSI). In June 2013 its operation was demonstrated every Tuesday, Wednesday and Thursday from 11AM to 3PM.

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Edmund Berkeley's "Giant Brains," the First Popular Book on Electronic Computers 1949

In 1949 mathematician and actuary Edmund Berkeley issued Giant Brains or Machines that Think, the first popular book on electronic computers, published years before the public heard much about the machines. The work was published by John Wiley & Sons who were enjoying surprising commercial success with Norbert Wiener's much more technical book, Cybernetics.

Among many interesting details, Giant Brains contained a discussion about a machine called Simon, which has been called the first personal computer. 

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Foundation of MIT's Lincoln Laboratory and SAGE 1949 – 1951

In August 1949, the Soviet Union exploded an atomic bomb. When Truman administration broke the news a month later the disclosure provoked a wave of fear and confusion — a reaction that intensified with the equally frightful revelation that the Soviets had developed long-range bombers capable of crossing the North Pole and attacking the United States.

To develop an automated detection and interception system to protect the entire U.S. from incoming bombers, in 1949, under the name Project Charles, the Air Force funded a project proposed by George Valley and Jay Forrester of MIT to develop a military grade version of the Whirlwind computer. The Final Report of the Air Defense Systems Engineering Committee (1950) concluded that the United States was unprepared for the threat of an air attack, and, as a result, in 1951 MIT's Lincoln Laboratory was founded in Lexington, Massachusetts, as a federally funded research and development center, initially focused on improving the nation's air defense system through advanced electronics. 

Because of MIT's management of the Radiation Laboratory  during World War II, and the experience of some of its staff on the Air Defense Systems Engineering Committee, and MIT's proven competence in electronics, the U.S. Air Force recommended that MIT could provide the research needed to develop an air defense that could detect, identify, and ultimately intercept air threats. However, it was soon determined that technology based on the Whirlwind computer, which Valley and Forrester had originally recommended for the purpose, was clearly inadequate. Instead, the project evolved into the huge Semi-Automatic Ground Environment or SAGE system, development of which occurred from 1954 to 1963.

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The EDSAC, the First Easily Used Fully Functional Stored-Program Computer, Runs its First Program May 6, 1949

On May 6, 1949 Maurice V. Wilkes’s EDSAC, fully operational at the University of Cambridge Computer Laboratory, ran a program written by Wilkes for calculating a table of squares. It also ran a program written by David Wheeler for calculating a sequence of prime numbers. The EDSAC was the first easily used, fully functional stored-program computer to run a program.

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The First Stored-Program Computer in Australia November 1949

At the University of Melbourne in November 1949 the first test program was run on Trevor Pearcey's and Maston Beard’s CSIR (Council for Scientific and Industrial Research) Mk1, the first stored-program computer in Australia. In 1956 the machine was renamed CSIRAC.

Excluding the BINAC, which only operated for a short time, the CSIR Mk1 was one of only three stored-program computers operating in the world at this time.  CSIRAC, preserved at the Melbourne Museum, is one of only a very few first generation electronic computers that have survived, including the Zuse Z4, and one or two Ferranti Pegasus computers.

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1950 – 1960

"High-Speed Computing Devices," the First Textbook on How to Build an Electronic Computer 1950

In 1950 Engineering Research Associates of St. Paul, Minnesota, published High-Speed Computing Devices, the first textbook on how to build an electronic digital computer. Written in the form of a “cookbook,” the book described available computer components and how they worked. It included extensive bibliographies of the American computing literature and some of the English. 

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The IBM NORC, the First Supercomputer 1950 – 1954

Between 1950 and 1954 IBM developed and built at Columbia University's Watson Scientific Computing Laboratory, 612 West 115th Street location, the Naval Ordnance Research Computer (NORC)—for the U.S. Navy Bureau of Ordnance. The NORC was the "first supercomputer," and "the most powerful computer on earth from 1954 to about 1963." The NORC’s multiplication unit remains the fastest ever built with vacuum tube technology.

IBM introduced the input-output channel as a feature on the NORC. This innovation synchronized the flow of data into and out of the computer while computation was in progress, relieving the central processor of that task.

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Simon, the First Personal Computer May – November 1950

Edmund Berkeley's "Simon," which has been called the first personal computer, developed out of his book, Giant Brains, or Machines That Think, published in November 1949, in which he wrote,

 “We shall now consider how we can design a very simple machine that will think.. Let us call it Simon, because of its predecessor, Simple Simon... Simon is so simple and so small in fact that it could be built to fill up less space than a grocery-store box; about four cubic feet. . . . It may seem that a simple model of a mechanical brain like Simon is of no great practical use. On the contrary, Simon has the same use in instruction as a set of simple chemical experiments has: to stimulate thinking and understanding, and to produce training and skill. A training course on mechanical brains could very well include the construction of a simple model mechanical brain, as an exercise."

One year later in an article published in Scientific American about “Simon,” in November 1950 Berkeley predicted that “some day we may even have small computers in our homes, drawing energy from electric power lines like refrigerators or radios.”

"Who built "Simon"? The machine represents the combined efforts of a skilled mechanic, William A. Porter, of West Medford, Mass., and two Columbia University graduate students of electrical engineering, Robert A. Jensen . . . and Andrew Vall . . . . Porter did the basic construction, while Jensen and Vall took the machine when it was still not in working order and engineered it so that it functioned. Specifically, they designed a switching system that made possible the follow-through of a given problem; set up an automatic synchronizing system; installed a system for indicated errors due to loss of synchronization; re-designed completely the power supply of themachine" (Fact Sheet on "Simon." Public Information Office, Columbia University, May 18, 1950).

"The Simon's architecture was based on relays. The programs were run from a standard paper tape with five rows of holes for data. The registers and ALU could store only 2 bit. The data entry was made through the punched paper or by five keys on the front panel of the machine. The output was provided by five lamps. The punched tape served not only for data entry, but also as a memory for the machine. The instructions were carried out in sequence, as they were read from the tape. The machine was able to perform four operations: addition, negation, greater than, and selection" (Wikipedia article on Simon (computer) accessed 10-10-2011).

In his 1956 article, "Small Robots-Report," Berkeley stated that he had spent $4000 developing Simon. The single machine that was constructed is preserved at the Computer History Museum, Mountain View, California. Berkeley also marketed engineering plans for Simon, of which 400 copies were sold.

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MESM, the First Russian Stored-Program Computer November 6, 1950 – 1951

In 1951 Russian mathematician and computer scientist Sergei Lebedev had MESM, the first Russian stored-program computer, operational in Feofaniya (Ukrainian: Феофанія), Theophania, a suburb of Kiev.

"Work on MESM got going properly at the end of 1948 and, considering the challenges, the rate of progress was remarkable. Ukraine was still struggling to recover from the devastation of its occupation during WWII, and many of Kyiv’s buildings lay in ruins. The monastery in Feofania was among the buildings destroyed during the war, so the MESM team had to build their working quarters from scratch—the laboratory, metalworking shop, even the power station that would provide electricity. Although small—just 20 people—the team was extraordinarily committed. They worked in shifts 24 hours a day, and many lived in rooms above the laboratory. (You can listen to a lively account of this time in programme 3 of the BBC’s ”Electronic brains” series.) 

"MESM ran its first program on November 6, 1950, and went into full-time operation in 1951. In 1952, MESM was used for top-secret calculations relating to rocketry and nuclear bombs, and continued to aid the Institute’s research right up to 1957. By then, Lebedev had moved to Moscow to lead the construction of the next generation of Soviet supercomputers, cementing his place as a giant of European computing. As for MESM, it met a more prosaic fate—broken into parts and studied by engineering students in the labs at Kyiv’s Polytechnic Institute" (http://googleblog.blogspot.com/2011/12/remembering-remarkable-soviet-computing.html, accessed 12-25-2011)

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IBM's First Electronic Computer, the 701, is Designed 1951

In 1951 IBM decided to produce their first electronic computer, the 701. It was a machine for scientific applications based on the Princeton IAS design.

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The Paris symposium, "Les Machines á calculer et la pensée humaine," Occurs January 8 – January 13, 1951

From January 8-13, 1951 the Paris symposium, Les Machines á calculer et la pensée humaine (Calculating Machines and Human Thought) took place at l'Institut Blaise Pascal. Unlike the other early computer conferences, no demonstration of a stored-program electronic computer occurred. Louis Couffignal demonstrated the prototype of his non-stored-program machine.

Hook & Norman, Origins of Cyberspace (2002) no. 526.

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The First Ferranti Mark I is Delivered February 1951

In February 1951 the first Ferranti Mark I version of the Manchester University machine was delivered to the University of Manchester in England.

With the exception of the unique BINAC delivered to Northrop Aircraft in the United States, the Ferranti Mark I was the first commercially produced electronic digital computer delivered to a customer.

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NIMROD: The First Special Purpose Digital Computer Designed to Play a Game May 5, 1951

For the Festival of Britain Exhibition of Science in South Kensington, London, which opened on May 5, 1951 in commemoration of the hundredth anniversary of the Great Exhibition of 1851, Ferranti built a special purpose computer called NIMROD that played the ancient game of Nim, a mathematical game of strategy. 

NIMROD was the first digital computer designed specifically to play a game, though its actual purpose was to illustrate the principles of the digital computer to the public when almost no one had seen or interacted with a computer. Because of the number of vacuum tubes involved, the machine was 12 feet wide, 5 feet tall and 9 feet deep. When the Festival of Britain ended, in October 1951, the computer was displayed at the Berlin Industrial Show. According to the Wikipedia article on Nimrod (computing), so significant was the computer considered when it was exhibited in there that "famous German politicians were present including Konrad Adenauer, the Federal Chancellor of the Federal Republic of Germany (FRG) and Ludwig Erhard, the Federal Minister for Economic Affairs." 

In Berlin, the NIMROD

"was so popular that people ignored the free beer (in Berlin!!!...though the beer was English beer, I suppose). The beer was at the other end of the same room but people instead watched the 'electronic brain' beat its human competitors. In part the excitement was caused because on the first day Nimrod had beaten Ludwig Erhard, the German Federal Minister for Economic Affairs, three times in a row. The age of computers outwitting humans had started" (http://www.cs4fn.org/binary/nim/nim.php, accessed 02-01-2014).

To help explain the NIMROD computer to the British public Ferranti published a pamphlet priced 1s 6d entitled Faster than Thought. The Ferranti Nimrod Digital Computer. Discovery magazine published an artist's watercolor impression of the NIMROD in their March 1951 issue. NIMROD was further discussed in Bertram Bowden's book, Faster than Thought (1953), chapter 25. 

NIMROD was conceived by Ferranti employee John M. Bennett, who received his PhD in computing at Cambridge under Maurice Wilkes, and later became the first professor computer science in Australia. Bennett got the idea of a Nim-playing computer from the Nimatron, an electro-mechanical machine exhibited at the 1939-1940 World’s Fair in New York City.

In 1994 Bennett reminisced:

"Ferranti had undertaken to display a computer at the 1951 Festival of Britain, and late in 1950 it became evident that this promise could not be fulfilled. I suggested that a machine to play the game of NIM against all comers should be constructed with a versatile display to illustrate the algorithm and programming principles involved. The design was implemented by a Ferranti engineer, Raymond Stuart-Williams, who later joined RCA.

"In its simplest form, two players with several piles of, say, matches play the game of Nim. The players move alternately, each removing one or more of the matches from any one pile. Whoever removes the last match wins.

" The machine was a great success but not quite in the way intended, as I discovered during my time as spruiker on the Festival stand. Most of the public were quite happy to gawk at the flashing lights and be impressed. A few took an interest in the algorithm and even persisted to the point of beating the machine at the game. Only occasionally did we receive any evidence that our real message about the basics of programming had been understood" (http://www.goodeveca.net/nimrod/bennett.html, accessed 02-01-2014).

In February 2014 a 55 second sound recording of radio columnist Paul Jennings giving his impressions of the NIMROD in 1951 was available at this link

A reduced size replica of Nimrod was later built for the Computerspielemuseum Berlin.

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Maurice Wilkes Introduces Microprogamming July 9 – July 12, 1951

From July 9-12, 1951 the second English electronic computer conference was held at the University of Manchester to inaugurate the first Ferranti Mark 1. There Maurice Wilkes introduced the term microprogramming, referring to the design of control circuits. The idea was not widely accepted until the following decade. (See Reading 8.8.)

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Once Finally Operational, the EDVAC is Obsolete 1952

In 1952 the EDVAC binary stored-program computer, planning for which had started in 1944, with development starting in 1947-48, was finally operational at the Moore School in Philadelphia. By this time it was essentially obsolete.

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Vaccuum Tubes Especially Designed for Digital Circuits 1952

In 1952 manufacturers began producing vacuum tubes especially designed for use in digital circuits.

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The First Electronic Computer Produced in France: Not a Stored-Program Computer 1952

In 1952 Compagnie des Machines Bull, the first French electronic computer manufacturer, produced its Gamma 3 electronic calculator. It was not a stored-program computer.

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The First Trackball 1952 – 1953

In 1952 British electrical engineer Kenyon Taylor and team, working on the Royal Canadian Navy's DATAR project (a pioneering computerized battlefield information system) invented the first trackball, a precursor of the computer mouse. It used a standard Canadian five-pin bowling ball. The DATAR system was first successfully tested on Lake Ontario in autumn 1953.

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The IAS Machine is Fully Operational June 10, 1952

The IAS computer was fully operational at Princeton on June 10, 1952.

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The First Electronic Computer in Germany September 1952

In September 1952 Heinz Billing's G1 was in full operation at the Max Planck Institute in Göttingen, directed by Werner Heisenberg. This was the first electronic computer in Germany. It used drum memory, but it was not a stored-program machine.

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IBM Produces an "Electronic Data Processing Machine" December 1952

In December 1952 IBM introduced the 701, their first stored-program electronic computer for commercial production. Designed by Nathaniel Rochester, and based on the IAS machine at Princeton, the IBM 701 was intended for scientific use. Feeling that the word "computer" was too closely associated with UNIVAC, IBM called the 701 an “electronic data processing machine.” IBM eventually sold nineteen of these machines. (See Reading 8.9.)

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The IBM 650: The First Mass-Produced Computer 1953

In 1953 IBM Endicott, New York, announced the IBM 650 Magnetic Drum Data Processing Machine. This was the first mass-produced computer. Between 1953 and 1962 almost 2000 systems were produced.

"the IBM 650 Magnetic Drum Data Processing Machine brought a new level of reliability to the young field of electronic computing. For example, whenever a random processing error occurred, the 650 could automatically repeat portions of the processing by restarting the program at one of a number of breaking points and then go on to complete the processing if the error did not reoccur. That was a big improvement over the previous procedure requiring the user to direct the machine to repeat the process.

"At the time the 650 was announced, IBM said it would be "a vital factor in familiarizing business and industry with the stored program principles." And it certainly did just that.

"The original market forecast for the 650 envisioned that a mere 50 machines would be sold or installed. But by mid-1955, there already were more than 75 installed and operating, and the company expected to deliver "more than 700" additional 650s in the next few years. Just one year later, there were 300 machines installed -- many more times than all of the IBM 700 series large-scale computers combined -- and new 650s were coming off the production line at the rate of one every day. In all, nearly 2,000 were produced before manufacturing was completed in 1962. No other electronic computer had been produced in such quantity.

"In net terms, the development requirement underlying the 650 was for a small, reliable machine offering the versatility of a stored-program computer that could operate within the traditional punched card environment. IBM -- and the industry -- wanted a machine capable of performing arithmetic, storing data, processing instructions and providing suitable read-write speeds at reasonable cost. The magnetic drum concept was seen as the answer to the speed and storage problems.

"Data and instructions were stored in the form of magnetized spots on the surface of a drum four inches in diameter and 16 inches long, which rotated 12,500 times a minute. The drum memory could hold 20,000 digits at 2,000 separate "addresses" (http://www-03.ibm.com/ibm/history/exhibits/650/650_intro2.html, accessed 10-22-2013).

On September 14, 1956 IBM announced the 355 disk memory unit for the IBM 650.  Systems incorporating the 355 were known as the 650 RAMAC.

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IBM Installs its First Stored Program Electronic Computer, the 701, but They Don't Call it a Computer March 27, 1953

"The 701 has at least 25 times the over-all speed but is less than one-quarter the size of IBM's Selective Sequence Electronic Calculator, which was dismantled to make room for its speedier successor."

"During its five-year reign as one of the world's best-known "electronic brains," the SSEC solved a wide variety of scientific and engineering problems, some involving many millions of sequential calculations. Such other projects as computing the positions of the moon for several hundred years and plotting the courses of the five outer planets -- with resulting corrections in astronomical tables which had been considered standard for many years -- won such popular acclaim for the SSEC that it stimulated the imaginations of pseudo-scientific fiction writers and served as an authentic setting for such motion pictures as "Walk East on Beacon," a spy-thriller with an FBI background.

"Though the 701 occupies the same quarters as the SSEC, which it rendered obsolete, it is not "built in" to the room as was its predecessor. Instead, it is smartly housed between serrated walls of soft-finished aluminum. A balconied conference room, overlooking the calculator and, separated from it by sloping plate glass, provides a vantage point for observing operations and discussing computations. Ample space is provided for writing the complex and abstract equations that are the stock in trade of engineers and scientists in an age of atomic energy and supersonic flight.

"The 701 uses all three of the most advanced electronic storage, or "memory" devices -- cathode ray tubes, magnetic drums and magnetic tapes. The computing unit uses small versions of the familiar electronic tubes, which are able to count at millions of pulses a second. In addition, several thousand germanium diodes are used in place of vacuum tubes, with resultant savings in space and power requirements.

"The 701 was designed for scientific and research purposes, and similar components are adaptable to the requirements of accounting and record-keeping. Research on commercial, data processing machines is under way.

"The 701 is capable of performing more than 16,000 addition or subtraction operations a second, and more than 2,000 multiplication or division operations a second. In solving a typical problem, the 701 performs an average of 14,000 mathematical operations a second."

(quotations from IBM's original May 27, 1953 press release from the IBM Archives website).

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The First Transistor Computer November 1953

In November 1953 the University of Manchester's experimental Transistor Computer became operational for the first time. This appears to be the first stored-program computer to use mainly transistors as switches rather than vacuum tubes. The transition from vacuum tubes to transistors in computer design was generally delayed because of reliablility problems in early transistor manufacturing.

"There were two versions of the Transistor Computer, the prototype, operational in 1953, and the full-size version, commissioned in April 1955. The 1953 machine had 92 point-contact transistors and 550 diodes, manufactured by STC. It had a 48-bit machine word. The 1955 machine had a total of 200 point-contact transistors and 1300 point diodes, which resulted in a power consumption of 150 watts. There were considerable reliability problems with the early batches of transistors and the average error free run in 1955 was only 1.5 hours. The Computer also used a small number of tubes in its clock generator, so it was not the first fully transistorized machine" (Wikipedia article on Transistor Computer, accessed 09-19-2013).

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The Deuce Computer (After the Pilot ACE, of Course) 1954

In 1954 English Electric constructed a commercial version of Alan Turing’s Pilot ACE called DEUCE.

Thirty-three of the DEUCE machines were sold, the last in 1962.

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First Computer to Incorporate Indexing & Floating Point Arithmetic 1954

In 1954 IBM announced the 704. It was the first commercially available computer to incorporate indexing and floating point arithmetic as standard features. The 704 also featured a magnetic core memory, far more reliable than its predecessors’ cathode ray tube memories. A commercial success, IBM produced one hundred twenty-three 704s between 1955 and 1960.

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The First Light Pen 1954 – 1963

In 1954 development began for NORAD on the SAGE Air Defense System, using a computer built by IBM after a design based on the Whirlwind. The system included the first light pen.

The full SAGE (Semi-Automatic Ground Environment) automated control system for tracking and intercepting enemy bomber aircraft was completed by 1963.

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Texas Instruments Manufactures the First Silicon Transistor May 10, 1954

In 1954 Texas Instruments manufactured the first silicon transistor, the 900-905 series.

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Magnetic Core Storage Units 1955

In 1955 IBM developed magnetic core storage units, a dramatic improvement over cathode ray tube memory technology. By successfully adapting pill-making machines for production, IBM greatly improved the manufacture of these tiny, “doughnut” shaped, iron oxide cores, making the cores reliable and cost effective enough to serve as the basic technology behind every computer’s main memory until the early 1970s.

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"The Design of Machines to Simulate the Behavior of the Human Brain" March 1955 – December 1956

At the 1955 Institute of Radio Engineers (IRE) Convention held in New York in March the Professional Group on Electronic Computers (PGEC) sponsored a symposium on "The Design of Machines to Simulate the Behavior of the Human Brain." The four panel members were Warren McCulloch of MIT, Anthony G. Oettinger of Harvard, Otto H. Schmitt of the University of Minnesota, and Nathaniel Rochester of IBM. The moderator was Howard E. Tompkins, then of Burroughs Corporation.

After the panel members read prepared statements, and a brief discussion, a group of invited questioners cross-examined the panel members. The invited questioners were Marvin Minsky, then of Harvard, Morris Rubinoff of the University of Pennsylvania, Elliot L. Gruenberg of the W. L. Maxson Corporation, John Mauchly, of what was then Remington Rand, M. E. Maron of IBM, and Walter Pitts of MIT. The transcript of the symposium was edited by the speakers with the help of Howard Tompkins, and published in the IRE Transactions on Electronic Computers, December 1956, 240-255.

From the transcript of the symposium, which was available online when I wrote this entry in April 2014, we see that many of the issues of current interest in 2014 were being discussed in 1955-56. McCulloch began the symposium with the following very quotable statement:

"Since nature has given us the working model, we need not ask, theoretically, whether machines can be built to do what brains can do with information. But it will be a long time before we can match this three-pint, three-pound, twenty-five-watt computer, with its memory storing 10¹³ or 10 [to the 15th power] bits with a mean half-life of half a day and successful regeneration of 5 per cent of its traces for sixty years, operating continuously wih its 10 [to the 10th power] dynamically stable and unreplaceable relays to preserve itself by governing its own activity and stabilizing the state of the whole body and its relation to its world by reflexive and appetitive negative feedback."

As I read through this discussion, I concluded that it was perhaps the best summary of ideas on the computer and the human brain in 1955-1956. As quoting it in its entirety would have been totally impractical, I instead listed the section headings and refer those interested to the original text:

McCulloch: "Brain," A Computer With Negative Feedback

Oettinger: Contrasts and Similarities

Rochester: Simulation of Brain Action on Computers

Schmitt: The Brain as a Different Computer


Chemical Action, Too

Cell Assemblies

Why Build a Machine "Brain"?

Is Systematicness Undesirable?

Growth as a Type of Learning

What Does Simultation Prove?

The Semantics of Reproduction

Where is the Memory?

"Distributed Memories"

"Memory Half-Life"

Analog vs. Digital

Speed vs. Equipment

The Neurophysiologists' Contribution

Pattern Recognition

Creative Thinking by Machines?

What Model Do We Want?

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The First Solid State Computer April 1955 – December 1957

In April 1955 IBM announced the development of the IBM 608 calculator, the first all solid-state (fully transistorized) computer commercially marketed. The machine was first shipped to customers in December 1957. Development of the 608 was preceded by prototyping an experimental all-transistor version of the 604. This was built and demonstrated in October 1954, but was not commercialized.

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The First Full-Scale Programmable Japanese Computer October 1955

ETL-Mark-2, the first full-scale programmable computer in Japan, was produced by the Electrotechnical Laboratory in Roppongi, Tokyo. It was built from 21,000 relays, and did not store a program.

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The First Step Toward Automation of Logic Minimalization 1956

A primary goal in electronic circuit design is obtaining the smallest logic circuit (Boolean formula) that represents a given Boolean function or truth table. In his Ph.D. thesis in electrical engineering at MIT entitled Algebraic Minimization and the Design of Two-Terminal Contact Networks, Edward J. McCluskey developed the first algorithm for designing combinational circuits — the Quine-McCluskey logic minimization procedure. This was the first step toward automation of logic minimization that could be implemented on a computer.

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The First Japanese Stored-Program Computer March 1956

In March 1956 FUJIC, the first Japanese stored-program electronic computer was operational. It was designed and built by essentially one person—Dr. Okazaki Bunji—for the Fuji Photo Film Company in Odawara, western Kanagawa Prefecture, Japan. The project began in 1949.

"Originally designed to perform calculations for lens design by Fuji, the ultimate goal of FUJIC's construction was to achieve a speed 1,000 times that of human calculation for the same purpose – amazingly, the actual performance achieved was double that number.

"Employing approximately 1,700 vacuum tubes, the computer's word length was 33 bits. It had an ultrasonic mercury delay line memory of 255 words, with an average access time of 500 microseconds. An addition or subtraction was clocked at 100 microseconds, multiplication at 1,600 microseconds, and division at 2,100 microseconds."

FUJIC is preserved in The National Museum Of Nature and Science in Tokyo.

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The First Commercial Computer Designed to Use a Moving Head Hard Drive for Secondary Storage September 4 – September 13, 1956

On September 4, 1956 IBM announced the IBM 350 disk storage unit or 350 RAMAC for the IBM 305 RAMAC, which they introduced on September 13, 1956. The IBM 305 RAMAC was the first commercial computer that used a moving head hard disk drive (magnetic disk storage) for secondary storage. One day later, on September 14, 1956, IBM announced the 650 RAMAC system, which paired an IBM 650 computer with the IBM 355 RAMAC disk storage unit.  However, the 650 RAMAC was a modification of the best-selling IBM 650 system rather than a new system designed specifically to use the RAMAC hard drives. 

"The 305 was one of the last vacuum tube computers that IBM built. It weighed over a ton. The IBM 350 disk system stored 5 million 7-bit (6 data bits plus 1 parity bit) alphanumeric characters (5 MB). It had fifty 24-inch-diameter (610 mm) disks. Two independent access arms moved up and down to select a disk, and in and out to select a recording track, all under servo control. Average time to locate a single record was 600 milliseconds. Several improved models were added in the 1950s. The IBM RAMAC 305 system with 350 disk storage leased for $3,200 per month in 1957 dollars, equivalent to a purchase price of about $160,000. More than 1,000 systems were built. Production ended in 1961; the RAMAC computer became obsolete in 1962 when the IBM 1405 Disk Storage Unit for the IBM 1401 was introduced, and the 305 was withdrawn in 1969.

"The original 305 RAMAC computer system could be housed in a room of about 9 m (30 ft) by 15 m (50 ft); the 350 disk storage unit measured around 1.5 square metres (16 sq ft). The first hard disk unit was shipped September 13, 1956. The additional components of the computer were a card punch, a central processing unit, a power supply unit, an operator's console/card reader unit, and a printer. There was also a manual inquiry station that allowed direct access to stored records. IBM touted the system as being able to store the equivalent of 64,000 punched cards.

"Programming the 305 involved not only writing machine language instructions to be stored on the drum memory, but also almost every unit in the system (including the computer itself) could be programmed by inserting wire jumpers into a plugboard control panel. . . .

"Currie Munce, research vice president for Hitachi Global Storage Technologies (which has acquired IBM's hard disk drive business), stated in a Wall Street Journal interview that the RAMAC unit weighed over a ton, had to be moved around with forklifts, and was delivered via large cargo airplanes. According to Munce, the storage capacity of the drive could have been increased beyond five megabytes, but IBM's marketing department at that time was against a larger capacity drive, because they didn't know how to sell a product with more storage" (Wikipedia article on IBM 305 RAMAC, accessed 10-22-2013).

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The First Computer with a Hard Drive: $10,000 per Megabyte September 14, 1956

On September  14, 1956, at IBM's Glendale Laboratory in Endicott, New York, IBM demonstrated the 650 RAMAC (Random Access Method of Accounting and Control) Magnetic Drum Data Processing Machine. The machine used a series of IBM 355 disk memory units. Also in September 1956 the machine was demonstrated at the U.S. Atomic Energy Commission exhibit at the Atoms for Peace Conference in Geneva.

"The addition of disk storage to the IBM 650 Magnetic Drum Data Processing Machine made possible 'single step processing.' Instead of accumulating data to be processed in stages, transactions could now be processed randomly as they occurred and every record affected by the transaction could be automatically adjusted in the same processing step. Each IBM 355 held 50 disks subdivided on each side into tracks for the storage of almost all active accounting records. Up to four IBM 355 units could be connected to the 650 system" (http://www-03.ibm.com/ibm/history/exhibits/storage/storage_355.html, accessed 10-21-2013).

The 355 disk memory unit was the first hard drive. It permitted random access to any of the million characters distributed over both sides of 50 two-foot-diameter disks. It stored about 2,000 bits of data per square inch and had a purchase price of about $10,000 per megabyte. (By 1997 the cost of storing a megabyte on a hard drive dropped to around ten cents.)

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First Japanese Conference on Electronic Computers November 1956

I November 1956 the first Japanese conference on electronic computers was held at Waseda University, Shinjuku, Tokyo.  

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IBM Phases Out Vacuum Tubes 1957

In 1957 IBM phased out vacuum tubes in computer design:

“It shall be the policy of IBM to use solid-state circuitry in all machine developments. Furthermore, no new commercial machines or devices shall be announced which make primary use of tube circuitry.”

By this time IBM was satisfied with the reliability of transistors and convinced of the advantages of solid state over vacuum tube technology.  

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Control Unit Based on Microprogramming 1957

In 1957 EDSAC 2, the first large-scale computer with a control unit based on microprogramming, became operational at the University of Cambridge.

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SAGE: Physically the Largest Computers Ever Built 1957

In 1957 the first SAGE (Semi-Automatic Ground Environment)  AN/FSQ-7 (DC-01) computer was operational on a limited basis for the SAGE Air Defense System at McGuire Air Force Base in Burlington County, New Jersey.  Twenty AN/FSQ-7s would eventually be built. The AN/FSQ-7 computer contained 55,000 vacuum tubes, occupied 0.5 acres (2,000 m2) of of floor space, weighed 275 tons, and used up to three megawatts of power. Performance was about 75,000 instructions per second. From the standpoint of physical dimensions, the fifty-two AN/FSQ-7s remain the largest computers ever built.  

"Although the machines used a large number of vacuum tubes, the failure rate of an individual tube was low due to efforts in quality control and a novel quality assurance system called marginal checking that discovered tubes that were growing weak, before they failed. Each SAGE site included two computers for redundancy, with one processor on "hot standby" at all times. In spite of the poor reliability of the tubes, this dual-processor design made for remarkably high overall system uptime. 99% availability was not unusual."

The system allowed online access, in graphical form, to data transmitted to and processed by its computers. Fully deployed by 1963, the IBM-built early warning system remained operational until 1984. With 23 direction centers situated on the northern, eastern, and western boundaries of the United States, SAGE pioneered the use of computer control over large, geographically distributed systems.

"Both MIT and IBM supported the project as contractors. IBM's role in SAGE (the design and manufacture of the AN/FSQ-7 computer, a vacuum tube computer with ferrite core memory based on the never-built Whirlwind II) was an important factor leading to IBM's domination of the computer industry, accounting for more than a half billion dollars in revenue, nearly 10% of IBM's income in the late 1950s" (Wikipedia article on Semi-Automatic Ground Environment, accessed 03-03-2012).

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So-Called Second Generation of Computers 1957

In 1957 commercial transistorized computers, including the UNIVAC Solid State 80 and the Philco TRANSAC S-2000, were introduced. These solid-state machines inaugurated the so-called second generation of electronic computers.

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The First Significant Computer Music Composition 1957

In 1957 Lejaren Hiller and Leonard Isaacson of the University of Illinois at Urbana-Champaign collaborated on the first significant computer music composition, the Illiac Suite, composed on the University of Illinois ILLIAC I computer.

The ILLIAC I was the first von Neumann architecture computer built and owned by an American university.

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The Premature Death of John von Neumann February 8, 1957

On February 8, 1957 mathematician and physicist John von Neumann died of cancer at the age of fifty-four. Like the death of Alan Turing at the age of 42, von Neumann's premature death was an enormous loss for computer science, as well as for mathematics and physics.

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The First Transistorized Supercomputer 1958

In 1958 Seymour Cray of Control Data Corporation, Minneapolis, Minnesota, built the first transistorized supercomputer, the CDC 1604.

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The IBM 1401, a Relatively Inexpensive Computer 1958

In 1958 IBM announced their 1401, a relatively inexpensive computer that proved very popular with businesses, and began to compete seriously with existing punched-card tabulating equipment.

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The Burroughs Atlas Guidance Computer July 19, 1958

On July 19, 1958 the BurroughsAtlas Guidance” computer was used at Cape Canaveral to control the launch of the Atlas missile. It was one of the first computers to use transistors rather than vacuum tubes.

". . .the first machine was installed at the Cape Canaveral missile range in June 1957. Although Atlas missile launches started in September 1957, test patterns were transmitted to the missile in place of actual guidance commands for the first four flights. The first computer-controlled launch was on July 19, 1958. The computer had separate memory areas for instructions (2048 18-bit words) and data (256 24-bit words). The instruction area was increased to 2816 words, beginning with the Model III version, which was first delivered in December 1958. The Atlas guidance computer had no facilities for developing programs, so they were written on the UDEC II, the Datatron, and the 220, using simulator software. Burroughs was still doing Atlas programming on the 220 in 1964. In all, 18 Atlas guidance computers were built at a total project cost of $37 million. The computer was very reliable, and no Atlas launch was ever aborted due to computer failure." 

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The TX-2 Computer for the Study of Human-Computer Interaction 1959

In 1959 Wesley A. Clark designed and built the TX-2 computer at MIT’s Lincoln Laboratory in Lexington, Massachusetts. It had 320 kilobytes of fast memory, about twice the capacity of the biggest commercial machines. Other features were magnetic tape storage, an online typewriter, the first Xerox printer, paper tape for program input, and a nine inch CRT screen. Among its applications were development of interactive graphics and research on human-computer interaction.

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1960 – 1970

The First Commercially Available General Purpose Computer with Transistor Logic 1960

In 1960 IBM introduced a transistorized version of its vacuum-tube-logic 709 computer, the 7090. The 7090 was the first commercially available general purpose computer with transistor logic. It became the most popular large computer of the early 1960s.

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George Forsythe Coins the Term "Computer Science" 1961

In 1961 mathematician and founder of Stanford University's Computer Science department George E. Forsythe coined the term "computer science" in his paper "Engineering Students Must Learn both Computing and Mathematics", J. Eng. Educ. 52 (1961) 177-188, quotation from p. 177.

Of this Donald Knuth wrote, "In 1961 we find him using the term 'computer science' for the first time in his writing:

[Computers] are developing so rapidly that even computer scientists cannot keep up with them. It must be bewildering to most mathematicians and engineers...In spite of the diversity of the applications, the methods of attacking the difficult problems with computers show a great unity, and the name of Computer Sciences is being attached to the discipline as it emerges. It must be understood, however, that this is still a young field whose structure is still nebulous. The student will find a great many more problems than answers. 

"He [Forsythe] identified the "computer sciences" as the theory of programming, numerical analysis, data processing, and the design of computer systems, and observed that the latter three were better understood than the theory of programming, and more available in courses" (Knuth, "George Forsythe and the Development of Computer Science," Communications of the ACM, 15 (1972) 722).

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Wesley Clark Builds the LINC, Perhaps the First Mini-Computer May 1961 – 1962

In May 1961 Wesley A. Clark, a computer scientist at MIT's Lincoln Laboratory, started building the LINC (Laboratory INstrument Computer). This machine, which some later called both the first mini-computer and a forerunner of  the personal computer, was first used in 1962. It was small table-top size, “low cost” ($43,000), had keyboard and display, file system and an interactive operating system. It's design was placed in the public domain. Eventually fifty of the machines were sold by Digital Equipment Corporation.

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Texas Instruments Delivers the First Integrated Circuit Computer: An Achievement in Miniaturization October 19, 1961

On October 19, 1961 Texas Instruments delivered the first integrated circuit computer to the U.S. Air Force.

“The advanced experimental equipment has a total volume of only 6.3 cubic inches and weighs only 10 ounces. It provides the identical electrical functions of a computer using conventional components which is 150 times its size and 48 times its weight and which also was demonstrated for purposes of comparison. It uses 587 digital circuits (Solid Circuit™ semiconductor net works) each formed within a minute bar of silicon material. The larger computer uses 8500 conventional components and has a volume of 1000 cubic inches and weight of 480 ounces.”

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Origins of the IBM System/360 December 28, 1961

On December 28, 1961 John W. Haanstra, Chairman, Bob O. Evans, Vice Chairman, and others at IBM issued as a confidential internal document Processor Products—Final Report of SPREAD Task Group.

In the period from 1952 through 1962, IBM produced seven families of systems—the 140, 1620, 7030 (Stretch), 7040, 7070, 7080, and 7090 groups. They were incompatible with one another, and both users and IBM staff recognized problems caused by this incompatibility. The SPREAD report, as adopted by IBM, led to the development of the IBM System/360 family of compatible computers and peripherals, and essentially reformed the company.

"IBM's public commitment to the SPREAD plan was embodied in the System/360, announced in Poughkeepsie on April 7, 1964. Six machines were announced: the 360 Model 30, 40, 50, 60, 62 and 70. Over the next few years, a number of additional systems were added to the 360 family.

"The SPREAD plan eventually allowed IBM to direct substantial resources toward the development of the full system—peripherals, programming, communications, and new applications. The success of System/360 is perhaps best measured by IBM's financial performance. In the six years from January 1, 1966 to December 31, 1971, IBM's gross income increased 2.3 times, from $3.6 billion to $8.3 billion, and net earnings after taxes increrased 2.3 times, from $477 million to $1.1 billion. In 1982 direct descendants of System/360 accounted for more than half of IBM's gross income and earnings.

"Perhaps most important, the SPREAD Report permitted IBM to focus on an excellence not possible with multiple architectures. It resulted in powerful new peripherals, programming, terminals, high-volume applications, and complementary diversifications whose future can only be imagined" (Bob O. Evans, "Introduction to SPREAD Report," Annals of the History of Computing 5 [1983] 5).  The text of the report was reprinted in the same journal issue on pp. 6-26.

Nearly all copies of this confidential report were destroyed. An original copy, donated by one of the authors, Jerome Svigals, is preserved in the Computer History Museum, Mountain View, California.

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The First Commercial Computers to Use Integrated Circuits 1964

In 1964 RCA announced the Spectra series of computers, which could run the same software as IBM’s 360 machines. The Spectra computers were also the first commercial computers to use integrated circuits.

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The IBM System/360 Family is Introduced April 7, 1964

On April 7, 1964 IBM announced the System/360 family of compatible machines.  All IBM System/360 products ran the same operating system—OS/360. Previously products developed by different divisions of IBM were incompatible.

IBM System/360 products were the first IBM computers capable of both commercial and scientific applications that were offered at what was then considered a “reasonable price.” Their architecture incorporated microprogramming.

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The Rand Tablet: One of the Earliest Tablet Computers and the First Reference to Electronic Ink August 1964

In August 1964 M. R. Davis and T. O. Ellis of The Rand Corporation, Santa Monica, California, published The RAND Tablet: A Machine Graphical Communication DeviceThey indicated that the device had been in use since 1963.

"The RAND table is believed to be the first such graphic device that is digital, is relatively low-cost, possesses excellent linearity, and is able to uniquely describe 10 [to the 6th power] locations in the 10" x 10" active table area. . . . the tablet has great potential no only in such applications as digitizing map information, but also as a working tool in the study of more esoteric applications of graphical languages for man-machine interaction. . . . " (p.iv)

"The RAND tablet device generates 10-bit x and 10-bit y stylus position information. It is connected to an input channel of a general-purpose computer and also to an oscilloscope display. The display control multiplexes the stylus position information with computer-generated information in such a way that the oscilloscope display contains a composite of the current pen position (represented as a dot) and the computer output. In addition, the computer may regenerate meaningful track history on the CRT, so that while the user is writing, it appears that the pen has "ink." This displayed "ink" is visualized from the oscilloscope display while hand-directing the stylus position on the tablet. users normally adjust within a few minutes to the conceptual superposition of the displayed ink and the actual off-screen pen movement. There is no apparent loss of ease or speed in writing, printing, constructing arbitrary figures, or even in penning one's signature" (pp. 2-3).

J. W. Ward, History of Pen Computing: Annotated Bibliography in On-line Character Recognition and Pen Computing: http://rwservices.no-ip.info:81/pens/biblio70.html#DavisMR64 , accessed 12-30-2009).

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Honeywell Produces an Early Home Computer? 1965

In 1965 Honeywell attempted to open the home computer market with its Kitchen Computer. The H316 was the first under-$10,000 16-bit machine from a major computer manufacturer. It was the smallest addition to the Honeywell "Series 16" line, and was available in three versions: table-top, rack-mountable, and self-standing pedestal. The pedestal version, complete with cutting board, was marketed by Neiman Marcus as "The Kitchen Computer.” It came with some built-in recipes, two weeks' worth of programming, a cook book, and an apron.

There is no evidence that any examples were sold.

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Carver Mead Builds the First Schottky-Barrier Gate Field Effect Transistor 1965 – 1966

In 1965 American electrical engineer and computer scientist Carver Mead of Caltech built the first working Schottky-barrier gate field-effect transistor: GaAs (gallium arsenide) MESFET (metal-semiconductor field effect transistor). This key amplifying device became a mainstay of high-frequency wireless electronics, used in microwave communication systems from radio telescopes to home satellite dishes and cellular phones. Using band-gap-engineered materials, the device evolved into the HEMT (High-electron-mobility transistor).

Mead, "Schottky Barrier Gate Field Effect Transistor," Proceedings of IEEE 54 (1966) 307−308.

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Jack Kilby and Texas Instruments Invent the First Hand-Held Electronic Calculator 1967 – June 25, 1974

In 1967 Texas Instruments filed the patent for the first hand-held electronic calculator, invented by Jack S. Kilby, Jerry Merryman, and Jim Van Tassel. The patent (Number 3,819,921) was awarded on June 25, 1974. This miniature calculator employed a large-scale integrated semiconductor array containing the equivalent of thousands of discrete semiconductor devices.

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Douglas Engelbart Invents the Computer Mouse June 27, 1967 – November 17, 1970

On June 27, 1967 electrical engineer and inventor Douglas C. Engelbart of the Augmentation Research Center at SRI filed a patent for an X-Y Position Indicator for a Display System. The device was covered on patent 3,541,541 granted on November 17, 1970. It eventually became known as the Mouse.

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Federico Faggin and Colleagues Invent Silicon Gate Technology at Fairchild Semiconductor February 1968

Silicon Gate Technology, invented in 1968 by Federico Faggin and colleagues at Fairchild Semiconductor in Palo Alto, California, was the first process technology used to fabricate commercial MOS (Metal Oxide Semiconductor) integrated circuits that was later widely adopted by the entire industry. Faggin also designed the first integrated circuit using a silicon gate, the Fairchild 3708. From the founding of Intel in July 1968 Robert Noyce and Gordon Moore adopted silicon gate technology, and within a few years it became the core technology for the fabrication of MOS integrated circuits worldwide. 

"In February 1968, Federico Faggin joined Les Vadasz’s group and was put in charge of the development of a low-threshold-voltage, self-aligned gate MOS process technology. Federico Faggin's first task was to develop the precision etching solution for the amorphous silicon gate, and then he created the process architecture and the detailed processing steps to fabricate MOS ICs with silicon gate. He also invented the ‘buried contacts,’ a method to make direct contact between amorphous silicon and silicon junctions, without the use of metal, a technique that allowed a much higher circuit density, particularly for random logic circuits.

"After validating and characterizing the process using a test pattern he designed, Federico Faggin made the first working MOS silicon gate transistors and test structures by April 1968. He then designed the first integrated circuit using silicon gate, the Fairchild 3708, an 8-bit analog multiplexer with decoding logic, that had the same functionality of the Fairchild 3705, a metal-gate production IC that Fairchild Semiconductor had difficulty making on account of its rather stringent specifications.... (Wikipedia article on Self-Aligned gate, accessed 12-02-2013).

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Landmark Products from the Early Years of Intel Corporation July 18, 1968 – 1985

On July 18, 1968 Robert Noyce, Gordon Moore and Andrew Grove from Fairchild Semiconductor founded NM Electronics, later known as Intel. The company's first property was purchased in Santa Clara, California.

1970: The Intel 1103

In 1970 Intel announced the Intel 1103, the world's first commercially available Dynamic Random Access Memory (DRAM) chip (1K bit pMOS dynamic RAM ICs).

1971: The Intel 4004

In November 1971 announced the first microprocessor: the  Intel 4004  four-bit central processor logic chip (U.S. Patent #3,821,715). Invented by Intel engineers Federico FagginMarcian Edward "Ted" HoffStanley Mazor and Masatosi Shima, this was the first microprocessor. The size of "a little fingernail," the 4004 contained 2400 transistors and delivered more computing power than the ENIAC, which occupied a large room.

Quoting from:

"The Crucial Role Of Silicon Design In The Invention Of The Microprocessor (A Testimonial from Federico Faggin, designer of the 4004 and developer of its enabling technology)

"Every time there is a new and important invention, there are many people who claim to be their inventor. This is also the case for the microprocessor. What are then the criteria to determine what the invention is and who invented it? What is exactly the microprocessor and what is novel about it? 

"The microprocessor is the central processing unit (CPU) of a general-purpose electronic computer implemented in a single integrated circuit. The Intel 4004 was unquestionably the world’s first commercial microprocessor. No one had commercialized a single-chip CPU prior to Intel. There are people, however, who claim to have built CPUs in more than one chip before the 4004, although they were never commercialized as chip-sets but were used only in proprietary equipment. For example, Raymond Holt claims to have built with his team a three-chip microprocessor in 1969 for the US Navy’s F-14A; Lee Boysel of Four Phase Systems Inc., claims that he and his team created the first microprocessor, which was incorporated as part of a system, in 1969. Although their contributions were remarkable, their CPU implementation, not being a single chip, was not a microprocessor. 

"Why is one chip so much different or better than two or three chips? If we accept to call a microprocessor a three-chip implementation of a CPU, then why shouldn’t a four or five-chip implementation be also called a microprocessor? Pretty soon it would be impossible to distinguish a microprocessor from a CPU board built with conventional components! A single chip is important not only because of its simplicity and elegance, but because a one-chip CPU is the irreducible minimum for a CPU, thus optimizing all the critical requirements of size, speed, cost and energy consumption. The microprocessor changed the world of computing exactly because it reduced to an absolute minimum the size, cost and energy consumption of a CPU while maximizing its speed. 

"The existence of multiple-chip CPU realizations predating the 4004 indicates that the critical contribution of the 4004 in the industry was its implementation in a single chip rather than in multiple chips. This fact places much emphasis on the fundamental role played by the chip design that enabled the integration of the 4004 in a single chip, more than on its architecture. Simple CPU architectures requiring two to three thousand transistors – the same number of transistors used in the 4004 -- were generally known in 1968-1969, however it was not possible to integrate all those transistors in a single chip with the MOS technology available at that time.

"The primary reason for the appearance of the microprocessor in 1971, rather than a few years later and possibly by other companies, was the existence of the MOS Silicon Gate Technology (SGT). With the silicon gate technology, twice as many transistors could be integrated in the same chip size than with conventional metal gate MOS technology, using the same amount of energy, and with a speed advantage of about 4:1. This technology, originally developed by Federico Faggin at Fairchild Semiconductor in 1968, had also been adopted by Intel. In 1970, only Fairchild and Intel had been able to master the SGT. The 4004 could be integrated and made to function in a single chip not only because of Faggin’s intimate understanding of the silicon gate technology and his skills as a chip designer, but also because of all the additional technological and circuit innovations he created to make it possible (new methodology for random logic using silicon gatebootstrap loadburied contact, power-resettable flip-flop - US patent 3.753.011-, new flip-flop design used in a novel static MOS shift register). 

"There is a very specific and quite striking example showing that the chip design, more than its architecture, was the key to the creation of the microprocessor -- it is the CPU used in the Datapoint 2200 terminal. Conceived in 1969 by Computer Terminal Corporation (CTC), Texas Instruments attempted to integrate this CPU in a single chip in 1971, as a custom project commissioned by CTC. Described in the press in mid-1971, only a few months after the 4004 completion, this chip never functioned and it was never commercialized. In early 1972, exactly the same CPU that Texas Instruments failed to make viable, was integrated at Intel (assigned to Hal Feeney, under Faggin’s supervision) using the silicon gate technology and the CPU design methodology created by Federico Faggin. This CPU became the Intel 8008 microprocessor, and was first commercialized in April 1972. The 8008 chip size was about half the size of Texas Instrument’s chip and it worked perfectly" (http://www.intel4004.com/hyatt.htm, accessed 12-02-2013). 

1972:  The Intel 8008

In April 1972 Intel introduced the 8008 microprocessor, the first 8-bit microprocessor. With an external 14-bit address bus that could address 16KB of memory, it became the CPU for the first commercial, non-calculator personal computers: the US SCELBI kit and the pre-built French Micral N and Canadian MCM/70, and the Datapoint 2200.

"Originally known as the 1201, the chip was commissioned by Computer Terminal Corporation (CTC) to implement an instruction set of their design for their Datapoint 2200 programmable terminal. As the chip was delayed and did not meet CTC's performance goals, the 2200 ended up using CTC's own TTL based CPU instead. An agreement permitted Intel to market the chip to other customers after Seiko expressed an interest in using it for a calculator" (Wikipedia article on Intel 8008, accessed 12-02-2013). 

1974:  The Intel 8080

In April 1974 Intel released the 8080 eight-bit microprocessor, considered by many to be the first general-purpose microprocessor. It featured 4,500 transistors and about ten times the performance of its predecessors. Within a year the 8080 was designed into hundreds of different products, including the MITS Altair 8800 designed by H. Edward Roberts. 

"The 8080 also changed how computers were created. When the 8080 was introduced, computer systems were usually created by computer manufacturers such as Digital Equipment CorporationHewlett Packard, or IBM. A manufacturer would produce the entire computer, including processor, terminals, and system software such as compilers and operating system. The 8080 was actually designed for just about any application except a complete computer system. Hewlett Packard developed the HP 2640series of smart terminals around the 8080. The HP 2647 was a terminal which ran BASIC on the 8080. Microsoft would market as its founding product the first popular programming language for the 8080, and would later acquire DOS for the IBM-PC" (Wikipedia article on Intel 8080, accessed 12-02-2013).

1978:  The Intel 8086

In 1978 Intel introduced the 8086 sixteen-bit microprocessor. The 8086 gave rise to the x86 architecture which eventually turned out as Intel's most successful line of processors.

1979: The Intel 8088

On July 1, 1979 Intel introduced the 8088 microprocessor, a low-cost version of the 8086 using an eight-bit external bus instead of the 16-bit bus of the 8086, allowing the use of cheaper and fewer supporting logic chips. It was the processor used in the original IBM PC.

1985:  The Intel 386

In 1985 Intel introduced the 32-bit 386 microprocessor. It featured 275,000 transistors— more than 100 times as many as the first Intel microprocessor, the 4004, developed in 1971.

(This entry was last revised on 01-18-2015.)

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Douglas Engelbart Demonstrates Hypertext, Text Editing, Windows, Email and a Mouse: "The Mother of All Demos" December 9, 1968

On December 8, 1968 Douglas Engelbart of the Stanford Research Institute, Menlo Park, California, presented a 100 minute demonstration  at the San Francisco Convention Center of an “oNLine System” (NLS), the features of which included hypertext, text editing, screen windowing, and email. To make this system operate, Engelbart used the mouse which he had invented the previous year.

In December 2013 numerous still images, a complete video stream of the demo, and 35 brief flash streaming video clips of different segments, were available from the Engelbart Collection at Stanford University at this link

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The Datapoint 2200: Precursor of the Personal Computer and the Microprocessor 1969 – 1971

In 1971 Phil Ray and Gus Roche of Computer Terminal Corporation of San Antonio, Texas, later known as Datapoint Corporation, began shipping the Datapoint 2200, a mass-produced programmable terminal, which could be used as a simple stand-alone personal computer.

"It was intended by its designers simply to be a versatile, cost-efficient terminal for connecting to a wide variety of mainframes by loading various terminal emulations from tape rather than being hardwired as most terminals were. However, enterprising users in the business sector (including Pillsbury Foods) realized that this so-called 'programmable terminal' was equipped to perform any task a simple computer could, and exploited this fact by using their 2200s as standalone computer systems. Equally significant is the fact that the terminal's multi-chip CPU (processor) became the embryo of the x86 architecture upon which the original IBM PC and its descendants are based.

"Aside from being one of the first personal computers, the Datapoint 2200 has another connection to computer history. Its original design called for a single-chip 8-bit microprocessor for the CPU, rather than a conventional processor built from discrete TTL modules. In 1969, CTC contracted two companies, Intel and Texas Instruments, to make the chip. TI was unable to make a reliable part and dropped out. Intel was unable to make CTC's deadline. Intel and CTC renegotiated their contract, ending up with CTC keeping its money and Intel keeping the eventually completed processor.

"CTC released the Datapoint 2200 using about 100 discrete TTL components (SSI/MSI chips) instead of a microprocessor, while Intel's single-chip design, eventually designated the Intel 8008, was finally released in April 1972. The 8008's seminal importance lies in its becoming the ancestor of Intel's other 8-bit CPUs, which were followed by their assembly language compatible 16-bit CPU's—the first members of the x86-family, as the instruction set was later to be known. Thus, CTC's engineers may be said to have fathered the world's most commonly used and emulated instruction set architecture from the mid-1980s to date" (Wikipedia article on Datapoint 2200, accessed 09-12-2012).

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1970 – 1980

Xerox PARC is Founded 1970

In 1970 Xerox opened the Palo Alto Research Center (PARC). PARC became the incubator of the Graphical User Interface (GUI), the mouse, the WYSIWYG text editor, the laser printer, the desktop computer, the Smalltalk programming language and integrated development environment, Interpress (a resolution-independent graphical page description language and the precursor to PostScript), and Ethernet.

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The Kenback-1, the First Stored-Program "Personal Computer" 1970 – 1971

In 1970 John Blankenbaker of Kenback Corporation, Northridge, California, designed and produced the Kenbak-1.  The machines, of which only forty were ever built, were designed as educational tools and offered for sale in Scientific American and Computerworld for $750 in 1971.  The company folded in 1973.

Unlike many earlier machines and calculating engines, the Kenbak-1 was a true stored-program computer that offered 256 bytes of memory, a wide variety of operations and a speed equivalent to nearly 1MHz. It was thus the first stored-program personal computer.

"Since the Kenbak-1 was invented before the first microprocessor, the machine didn't have a one-chip CPU but instead was based purely on discrete TTL chips. The 8-bit machine offered 256 bytes of memory (=1/4096 megabyte). The instruction cycle time was 1 microsecond (equivalent to an instruction clock speed of 1 MHz), but actual execution speed averaged below 1000 instructions per second due to architectural constraints such as slow access to serial memory.

"To use the machine, one had to program it with a series of buttons and switches, using pure machine code. Output consisted of a series of lights" (Wikipedia article on Kenbak-1, accessed 09-19-2013).

In 2013 John Blankenbaker's detailed account of the design, production, and operation of the Kenbak-1 was available from his website, www.kenbak.-1.net.

Also in 2013, "Official Kenbak-1 Reproduction Kits" were available from www.kenbakkit.com.

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The IBM System/370 Uses Semiconductor Memory June 30, 1970

On June 30, 1970 IBM announced the System/370, an upgrade for the 360, using semiconductor memory in place of magnetic cores.

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Gilbert Hyatt Files the First General Patent on the Microprocessor, Later Invalidated December 1970

In December 1970 Gilbert Hyatt filed a patent application entitled Single Chip Integrated Circuit Computer Architecture based on work begun in 1968. This was the first patent application for a microprocessor. The patent was granted in 1990 but later invalidated.

"A patent on the microcontroller [microprocessor], predating the only two Intel patents related to the MCS-4, was granted to Gilbert Hyatt in 1990. This patent described the architecture and logic design of a microcontroller, claiming that it could be integrated into a single chip. This patent was later invalidated in a patent interference case brought forth by Texas Instruments, on account that the device it described was never implemented and was not implementable with the technology available at the time of the invention" (http://www.intel4004.com/hyatt.htm, accessed 12-02-2013). 

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Bell & Newell Publish "Computer Structures" 1971

While teaching computer science at Carnegie Mellon University C. Gordon Bell and Allen Newell of the Rand Corporation in Pittsburgh published Computer Structures: Readings and Examples, a systematized presentation of the principles governing the design of computer systems.

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The HP-35, the First Handheld Scientific Calculator 1972

In 1972 Hewlett-Packard, Palo Alto, California, introduced the HP-35, their first pocket calculator, and the first pocket scientific calculator with trigonometric and exponential functions. The unit, which fit in a shirt pocket, was priced $395.

"Before the HP-35, the only practical portable devices for performing trigonometric and exponential functions were slide rules. Existing pocket calculators at the time were only four-function, i.e., they could only do addition, subtraction, multiplication, and division. It had been originally known simply as 'The Calculator', but Hewlett suggested that it be called the HP-35 because it had 35 keys" (Wikipedia article on HP-35, accessed 03-10-2012).

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Introduction of the MCM/70, the First Truly Portable Computer & the First Truly Usable Microcomputer System 1973

In December 1973 Microcomputer Computer Machines, Inc. ("MCM"), introduced the MCM/70 (MCM 70). MCM was started in 1971-1972 by Mers Kutt and associates in Kingston, Ontario, Canada, with the objective of designing, building, and marketing a state-of-the-art powerful, but portable, general-purpose microcomputer. One of the very first microcomputers, the MCM.70 was the first truly portable computer and arguably the first truly usable microcomputer system.

The MCM/70 included one or two digital tape drives in the single physical unit including the integral keyboard and display, with a total weight of about 20 pounds. To emphasize the MCM70's portability, MCM made an optional carrying case available so that the whole computer would fit under an airline seat. The MCM/70 and MCM/800, a more powerful model introduced in 1976, could be connected to any Diablo 630 compatible printer daisy wheel printer for printed output, but also for digitizing analog input. The MCM 800 was a desktop unit, with ribbon cables connecting the physically separate units. These could include a Diablo 630 compatible printer, a CRT display, additional digital cassette tape drives, a single or dual floppy disk unit, a 30 cps modem, and an 80-column card reader, as off-the-shelf units.

The MCM/70 used IBM-developed APL as its user language and was the first commercially available computer to make APL its primary or only user language. MCM continued APL as the user language on the MCM/700 and the later 800, but downplayed it in the MCM/1200, emphasizing instead the use of software packages writtin in APL. The MCM/70 provided the user with virtual storage as an automatic standard feature, as long as the computer was equipped with at least one tape drive or one disk drive. The MCM/70 was the first commercially available computer to do this. It gave the user the ability to do large data manipulation tasks, of the kind that would normally have required a mainframe, but,of course, more slowly on a very small and relatively in expensive computer. MCM continued providing automatic virtual storage to cover all of the computers in its line.

The MCM/70 was the first microcomputer that came bundled with its own operating system software: AVS. AVS managed the virtual storage transparently for the user, and provided the interface between APL and the hardware.The user accessed operating system facilities through APL, especially the enhanced "quad" functions. However, MCM provided an editor in AVS for use with APL which improved on the editor familiar to users of IBM'sAPL/360 implementations. MCM carried all of these features forward to the MCM700, 800, and 1200 models.

The MCM 70 provided a new level of comprehensiveness of hardware-software integration. It was the first clear instance of what is termed "co-design" where the computer software and hardware are designed at the same time, by people working together and deliberately seeking a common set of goals for the performance of the hardware when directed by the software. While the MCM700 preserved nearly all of this tight integration, the MCM/800 lost some in adding additional peripheral equipment, and the MCM/1200 lost more. For the MCM/70, more of the integration appears in the AVS operating system than in MCM's APL implementation, because of MCM's deliberate policy of keeping a very close compatibility withI BM's APL/360.

As advanced and sophisticated as were all of ACM’s hardware and software innovations, and as useful as the machines were to business customers before the PC revolution, MCM machines never achieved sufficiently high volume to allow lower unit cost, and their tightly integrated designs incorporated rigid hardware and software constraints. When the Apple II was introduced in April 1977, at a much lower price, and without the same constraints, it became an immediate success, taking sales away from MCM. Also, the Apple II's ability to run VisiCalc, the first electronic spreadsheet, was so compelling that many people bought the Apple II for that purpose alone. The Apple II, and, of course, the open architecture IBM PC, introduced in 1981, and its clones, captured the market that MCM targeted. By 1981, as the PC revolution began, the company was in trouble, and by 1985 MCM folded.

Stachniak, Zbigniew, Inventing the PC. The MCM/70 Story (2011).

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The Xerox Alto: Conceptually, the First Personal Computer System 1973

In 1973 the Alto computer system was operational at Xerox PARC. Conceptually the first personal computer system, the Alto eventually featured the first WYSYWG (What You See is What You Get) editor, a graphic user interface (GUI), networking through Ethernet, and a mouse. The system was priced $32,000.

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The Earliest Commercial, Non-Kit Personal Computer Based on a Microprocessor February 1973

In February 1973 the French company Réalisation d'Études Électroniques (R2E), founded by Paul Magneron and André Truong Trong Thi, offered the Micral N personal computer for sale. The Micral N was the earliest commercial, non-kit personal computer or microcomputer based on a microprocessor, specifically the Intel 8008.

"The software was developed by Benchetrit, with Alain Lacombe and Jean-Claude Beckmann working on the electrical and mechanical aspects. [François] Gernelle invented the Micral N, which was much smaller than existing minicomputers. The January 1974 Users Manual called it "the first of a new generation of mini-computer whose principal feature is its very low cost'....

"The computer was to be delivered in December 1972, and Gernelle, Lacombe, Benchetrit and Beckmann had to work in a cellar in Châtenay-Malabry for 18 hours a day in order to deliver the computer in time. The software, the ROM-based MIC 01 monitor and the ASMIC 01 assembler, was written on an Intertechnique Multi-8 minicomputer using a cross assembler. The computer was based on an Intel 8008 microprocessor clocked at 500 kHz. It had a backplane bus, called the Pluribus with 74-pin connector. 14 boards could be plugged in a Pluribus. With two Pluribus, the Micral N could support up to 24 boards. The computer used MOS memory instead of core memory. The Micral N could support parallel and serial input/output. It had 8 levels of interrupt and a stack. The computer was programmed with punched tape, and used a teleprinter or modem for I/O. The front panel console was optional, offering customers the option of designing their own console to match a particular application. It was delivered to the INRA in January 1973, and commercialized in February 1973 for FF 8,500 (about $1,750) making it a cost-effective replacement for minicomputers which augured the era of the PC" (Wikipedia article on Micral N, accessed 12-02-2013). 

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The First Computer Employing RISC 1974

In 1974 IBM built the first prototype computer employing RISC (Reduced Instruction Set Computer) architecture. Based on an invention by IBM researcher John Cocke, the RISC concept simplified the instructions given to run computers, making them faster and more powerful. It was implemented in the experimental IBM 801 minicomputer. The goal of the 801 was to execute one instruction per cycle.

In 1987 John Cocke received the A. M. Turing Award for significant contributions in the design and theory of compilers, the architecture of large systems and the development of reduced instruction set computers (RISC); for discovering and systematizing many fundamental transformations now used in optimizing compilers including reduction of operator strength, elimination of common subexpressions, register allocation, constant propagation, and dead code elimination.

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Virtual Machines 1974

In 1974 American computer scientist Gerald J. Popek of UCLA and Robert P. Goldberg published Formal Requirements for Virtualizable Third Generation Architectures, a set of conditions sufficient to support system virtualization efficiently in computer architecure. 

"Even though the requirements are derived under simplifying assumptions, they still represent a convenient way of determining whether a computer architecture supports efficient virtualization and provide guidelines for the design of virtualized computer architectures."

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The First Magnetic Card-Programmable Handheld Calculator 1974

In 1974 Hewlett-Packard, Palo Alto, California, introduced the HP-65, the  first magnetic card-programmable handheld calculator, featuring nine storage registers and room for 100 keystroke instructions. It also included a magnetic card reader/writer to save and load programs. The price was $795.

"Bill Hewlett's design requirement was that the calculator should fit in his shirt pocket. That is one reason for the tapered depth of the calculator. The magnetic program cards fed in at the thick end of the calculator under the LED display. The documentation for the programs in the calculator is very complete, including algorithms for hundreds of applications, including the solutions of differential equations, stock price estimation, statistics, and so forth" (Wikipedia article on HP-65, accessed 03-10-2012).

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Probably the First Advertised Personal Computer Sold in Kit Form March 1974

In March 1974 Computer Consulting of Milford, Connecticut advertised the SCELBI-8H (SCientific ELectronic BIological, pronounced "sell-bee") personal computer. Based on the first 8-bit microprocessor from Intel, the 8008, the 8H came with 1K of random-access memory and was available either fully assembled or in a kit (consisting of circuit boardspower supply, etc. that the purchaser assembled). The company placed ads in QSTRadio-Electronics and later in BYTE magazine. Though the 8H was preceded by the Micral N produced in France, some have called it the first personal computer advertised in kit form.

"No high-level programming language was available for the 8H in the beginning. Wadsworth wrote a book, Machine Language Programming for the 8008 and Similar Microcomputers, that taught the assembly language and machine language programming techniques needed to use the 8H. The book included a listing of a floating point package, making it one of the first examples of non-trivial personal-computer software distribution in the spirit of what would much later become known as open source. Because of the similarities between the 8008 and the 8080, this book was purchased by many owners of non-SCELBI hardware" (Wikipedia article on SCELBI, accessed 12-02-2013).

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The MITS Altair, the First Personal Computer to Get "Wide Notice" Among Enthusiasts January 1975 – 1976

In January 1975 H. Edward Roberts, working in Albuquerque, New Mexico, announced the MITS (Micro Instrumentation Telemetry Systems) Altair personal computer kit in an article in Popular Electronics magazine. The MITS Altair was first personal computer based on the Intel 8080 general-purpose microprocessor, and the first personal computer to get "wide notice" among enthusiasts. It also had an open architecture. The basic Altair 8800 sold for $397.

In March 1976 the first (and only) World Altair Computer Convention, took place in Albuquerque, New Mexico. Organized by David Bunnell of MITS, it was the world's first personal computer conference, and was an overwhelming success, with 700 people from 46 states and seven countries attending.

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The Apple I is Released July 1976

The first Apple Computer, designed and hand-built by Steve Wozniak, and known retrospectively as the Apple I (Apple 1) was demonstrated at the Homebrew Computer Club in Menlo Park, California in July 1976. Wozniak's friend Steve Jobs had the idea of manufacturing the computer for sale. Together they founded the Apple Computer Company, and to finance the production of their first product Jobs sold his only means of transportation, a VW van, and Wozniak sold his HP-65 calculator for $500. They built the Apple I in the garage of Jobs's parents' house in Palo Alto.  

"The Apple I went on sale in July 1976 at a price of US$666.66, because Wozniak liked the repeating digits and because they originally sold it to a local shop for $500 for the one-third markup. About 200 units were produced. Unlike other hobbyist computers of its day, which were sold as kits, the Apple I was a fully assembled circuit board containing about 60+ chips. However, to make a working computer, users still had to add a case, power supply transformers, power switch, ASCII keyboard, and composite video display. An optional board providing a cassette interface for storage was later released at a cost of $75" (Wikipedia article on Apple I, accessed 11-26-2011).

♦ Of the approximately 200 Apple 1s built, 43 were thought to survive in 2012.  Of those six were then thought to be in working order. For sales of original examples beginning in 2010 see the related database entry.

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The First Personal Computer Sold as a Fully Assembled Product 1977

In 1977 Apple Computer introduced the Apple II, the first personal computer sold as a fully assembled product, and the first with color graphics. When the first spreadsheet program, Visicalc, was introduced for the Apple II in 1979 it greatly stimulated sales of the computer as people bought the Apple II just to run Visicalc.

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Inaugurating the Concept of Office Automation 1977

In 1977 Wang Laboratories, Lowell, Massachusetts, introduced its VS minicomputer system, which became, for a time, one of the most popular office systems, "inaugurating the concept of office automation."

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Introduction of the LINPACK Benchmarks for the Measurement of Floating Point Computing Power 1979

In 1979 American computer scientist Jack Dongarra (University of Tennesse, Knoxville and Oak Ridge National Laboratory, Oak Ridge, TN) together Jim Bunch, Cleve Moler and Pete Stewart developed the LINPACK Benchmark, a measure of a system's floating point computing power. The LINPACK benchmark measures how fast a computer solves a dense n by n system of linear equations Ax = b, which is a common task in engineering. It is the benchmark used in the twice-annual ranking of the world's supercomputers by Top500.org.

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The "Mead & Conway Revolution" in VLSI Integrated Circuit Education 1979

In 1979 professor of electrical engineering, computer science and applied physics at Caltech Carver Mead, and electrical engineer and computer scientist Lynn Conway, Manager of LSI systems at Xerox PARC, published Introduction to VLSI Systems. This textbook, intended for all electrical engineering and computer science students, was the first VLSI design textbook for non-technologists. It was responsible for what was called the "Mead & Conway revolution" in VLSI integrated circuit education. In January 2014 documentary information on the Xerox PARC-Caltech collaboration culminating in the textbook was available at this link.

"Until recently the design of integrated circuitry has been the province of circuit and logic designers working within semiconductor firms. Computer architects have traditionally composed systems from standard integrated circuits designed and manufactured by these firms but have seldom participated in the specification and design of these circuits. Electrical Engineering and Computer Science (EE/CS) curricula reflect this tradition, with courses in device physics and integrated circuit design aimed at a different group of students than those interested in digital system architecture and computer science.

"This text is written to fill a current gap in the literature and to introduce all EE/CS students to integrated system architecture and design. Combined with individual study in related research areas and participation in large system design projects, this text provides the basis for a graduate course-sequence in integrated courses on the subject. The material can also be used to augement courses on computer architecture. We assume the reader's background contains the equivalent of introductory courses in computer science, electronic circuits, and digital design" (Preface v-vi).

"An important milestone that followed was the Multi Project Chip (MPC) service for fabricating the students' design exercise chips and the researcher's prototype chips at a reasonable cost. The first successful run of it was demonstrated at Lynn Conway's 1978 VLSI design course at MIT. A few weeks after completion of their design the students had the fabricated prototype in their hands, available for testing. Lynn Conway's improved new Xerox PARC MPC VLSI implementation system and service was operated successfully for a dozen universities by in late 1979. Lynn Conway's MPC technology was transferred to USC-ISI, becoming the foundation for the MOSIS System, which was used and evolved since 1981 as a national infrastructure for fast-turnaround prototyping of VLSI chip designs by universities and researchers.

"In 1980 DARPA began the DoD's new VLSI research program to support extensions of this work, resulting in many university and industry researchers being involved in following up the Mead-Conway innovations. The Mead & Conway revolution rapidly spread around the world and many national Mead & Conway scenes were organized, like the German multi-university E.I.S. project " (Wikipedia article on Mead & Conway revolution, accessed 12-29-2013).

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The First Silicon Compiler January 1979

In January 1979 the first Caltech Conference On Very Large Scale Integration (VLSI) took place at Caltech in Pasadena. At this meeting
David L. Johannsen, a graduate student of Carver Mead, presented a paper entitled "Bristle Blocks: A Silicon Compiler," describing his research on silicon compilation. This was the first use of the term to describe a software system that takes a user's specifications and automatically generates an integrated circuit (IC), translating the electronic design of a chip into the layout of the logic gates, including the actual masking from one transistor to another. The process is sometimes referred to as hardware compilation. Silicon compilation eventually created a new business model for the semiconductor industry, called fabless manufacturing.

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1980 – 1990

The Xerox Star: The "Office of the Future" 1981

In 1981 Xerox introduced the 8010 Star Information System, the first commercial system to incorporate a bitmapped display, a windows-based graphical user interface, icons, folders, mouse, Ethernet networking, file servers, printer servers and e-mail.

Xerox's 8010 Star was developed at Xerox's Systems Development Department (SDD) in El Segundo, California. A section of SDD ("SDD North") was located in Palo Alto, California, and included some people borrowed from Xerox's PARC. SDD's mission was to design the "Office of the Future"—a system, easy to use, that would incorporate the best features of the Xerox Alto, and could automate many office tasks.

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The Osborne 1: The First Commercially Successful "Portable" Computer April 1981

In April 1981 writer and computer entrepreneur Adam Osborne and Osborne Computer Corporation, Hayward, California, produced the first commercially successful "portable" computer, the Osborne 1. It weighed twenty-three pounds, ran the CP/M operating system, and sold for $1795, with $2000 worth of software included. Its main deficiencies were a tiny 5 inch (13 cm) display screen and use of single sided, single density floppy disk drives which could not contain sufficient data for practical business applications. Its 23 pound weight meant that the computer was more "luggable" than portable.

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IBM Introduces the IBM 5150- The IBM PC August 12, 1981

On August 12, 1981 IBM introduced their open architecture personal computer (PC) based on the Intel 8088 processor. The IBM PC  ran PC-DOS, the IBM-branded version of the 16-bit operating system, MS-DOS, provided by Microsoft. The machine was originally designated as the IBM 5150, putting it in the "5100" series, though its architecture was not directly descended from the IBM 5100.

On August 1, 1981 a review of the IBM PC appeared on USENET (accessed 10-16-2009).

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The First "Clamshell" Laptop? 1982

The GRiD Compass 1100, introduced by Grid Systems Corporation in 1982, was probably the first commercial computer created in a "clamshell" laptop format, and one of the first truly portable machines.

The 1100 included a magnesium clamshell case with a screen that folded flat over the keyboard, a switching power supply, electro-luminescent display, non-volatile bubble memory, and a built-in modem.

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Sun Microsystems Announces its First Workstation February 24, 1982

In May 1982 SUN Microsystems announced its first UNIX workstation, the Sun 1. The company had been founded in Santa Clara, California only three months earlier, on February 24, 1982, by Vinod Khosla, Andy Bechtolsheim, Bill Joy, and Scott McNealy—students at Stanford who worked on the Stanford University Network

"The initial design for what became Sun's first Unix workstation,  was conceived by Andy Bechtolsheim when he was a graduate student at Stanford University in Palo Alto, California. He originally designed the SUN workstation for the Stanford University Network communications project as a personal CAD workstation. It was designed as a 3M computer: 1 MIPS, 1 Megabyte and 1 Megapixel. It was designed around the Motorola 68000 processor with an advanced Memory management unit (MMU) to support the Unix operating system with virtual memory support. He built the first ones from spare parts obtained from Stanford's Department of Computer Science and Silicon Valley supply houses" (Wikipedia article on Sun Microsystems, accessed 06-12-2009).

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The First IBM PC Compatible Computer June 1982

In June 1982 Columbia Data Products (CDP) of Columbia, Maryland, introduced the MPC 1600 "Multi Personal Computer," an exact functional copy of the IBM PC model 5150 except for the BIOS, which was developed by a "clean room" reverse engineering process, thus avoiding copyright infringement. IBM had published the bus and BIOS specifications, wrongly assuming that this would be enough to encourage the add-on market, and prevent unlicensed copying of the design.

"As the first IBM PC clone, the MPC was actually superior to the IBM original. It came with 128 KiB RAM standard, compared to the IBM's 64 KiB maximum. The MPC had eight PC expansion slots, with one filled by its video card. Its floppy disk drive interface was built into the motherboard. The IBM PC, in contrast, had only five expansion slots, with the video card and floppy disk controller taking two of them. The MPC also included two floppy disk drives, one parallel and two serial ports, which were all optional on the original IBM PC. The MPC was followed up with a portable PC, the 32 pound (15 kg) "luggable" Columbia VP in 1983" (Wikipedia article on Columbia Data Products, accessed 01-01-2013).

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The First Cheap Home Computer, and the Best-Selling Computer of its Time August 1982

In August 1982 Commodore International, West Chester, Pennsylvania, issued the Commodore 64—"the first cheap home computer" at the price of $595. The Commodore 64 looked like a bulky keyboard, but included color graphics, and excelled at playing early video games. Between 1982 and 1984 30,000,000 units were sold, making it the best-selling personal computer model of this era. Roughly 10,000 commercial programs were produced for this computer.

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The First Scanner? November 1982

In November 1982 IBM introduced the Scanmaster 1, a mainframe computer terminal designed to scan, transmit and store images of documents electronically.

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The "Trash" 80: The First Notebook Computer? 1983

In 1983 the TRS-80, Model 100, made by Kyocera, Kyoto, Japan, and marketed in the U.S. in Radio Shack stores owned by Tandy Corporation of Fort Worth, Texas, introduced the concept of a "notebook" computer. More than 6,000,000 TRS-80s were sold; the introductory price was $1099.00.

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The First Commercially Available IBM PC Compatible ROM Bios 1983 – May 1984

During 1983 and the first part of 1984 Phoenix Technologies, then in Boston, Massachusetts, created the first commercially available IBM PC compatible ROM Bios. Licensability of this firmware interface, which would allow a computer to run the same operating system and the same applications as the IBM PC, enabled the rapid expansion of the IBM PC compatible computer industry. 

To defend against the inevitable copyright infringement suits expected to be brought by IBM, Phoenix engineers reverse-engineered the Bios using clean-room design, in which the software engineers had never read IBM's reference manuals: 

"Phoenix developed a 'clean room' technique that isolated the engineers who had been contaminated by reading the IBM source listings in the IBM Technical Reference Manuals. The contaminated engineers wrote specifications for the BIOS APIs and provided the specifications to 'clean' engineers who had not been exposed to IBM BIOS source code. Those 'clean' engineers developed code from scratch to mimic the BIOS APIs. This technique provided Phoenix with a defensibly non-infringing IBM PC-compatible ROM BIOS. Because the programmers who wrote the Phoenix code had never read IBM's reference manuals, nothing they wrote could have been copied from IBM's code, no matter how closely the two matched" (Wikipedia article on Phoenix Technologies, accessed 01-01-2013).

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One of the First Commercially Available Touchscreen Computers November 1983

In 1983 Hewlett-Packard, Palo Alto, California, introduced the HP-150, one of the earliest commercially available touchscreen computers. 

"The screen is not a touch screen in the strict sense, but a 9" Sony CRT surrounded by infrared emitters and detectors which detect the position of any non-transparent object on the screen. In the original HP-150, these emitters & detectors were placed within small holes located in the inside of the monitor's bezel (which resulted in the bottom series of holes sometimes filling with dust and causing the touch screen to fail; until the dust was vacuumed from the holes)" (Wikipedia article on HP-150, accessed 12-30-2009).

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The Greatest PC Keyboard of All Time? 1984 – 2008

In 1984 IBM introduced the model M keyboard, considered by PC World in July 2008 to be the "greatest keyboard of all time." The PC World article contained a remarkable series of images showing how the keyboard was engineered with captions describing its many virtues.

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Steve Jobs Introduces the "Mac" January 24, 1984

On January 24, 1984 Apple Computer introduced the Macintosh (Mac), with a graphical user interface (GUI) based on the Xerox Star system.

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The First Hand-Held Graphing Calculator October 1985

The Casio FX-7000G, the first hand-held graphing calculator, was introduced by Casio, Tokyo, Japan in October 1985. The calculator offered 82 scientific functions, which could be graphed, and was capable of manual computation for basic arithmetic problems.

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The First Commercially Available Tablet Computer September 1989

In 1989 GRiD Systems, a subsidiary of Tandy Corporation, Fort Worth, Texas, introduced the first commercially available tablet computer: the GRiDPad, which used an operating system based on MS-DOS.

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1990 – 2000

The First Tablet Computer with Wireless Connectivity April 1993 – July 1994

In April 1993 AT&T introduced the AT&T EO Personal Communicator, the first tablet computer with wireless connectivity via a cellular phone. The device, which provided wireless voice, email, and fax communications, was developed by GO/Eo, a subsidiary of GO Corporation, both of which were acquired by AT&T in 1993. As advanced as it was, the AT&T Personal Communicator was probably far ahead of the market. EO Inc., 52% owned by AT&T, failed to meet its revenue targets and shut down on July, 1994.

"Two models, the Communicator 440 and 880 were produced and measured about the size of a small clipboard. Both were powered by the AT&T Hobbit chip, created by AT&T specifically for running code from the C programming language. They also contained a host of I/O ports - modem, parallel, serial, VGA out and SCSI. The device came with a wireless cellular network modem, a built-in microphone with speaker and a free subscription to AT&T EasyLink Mail for both fax and e-mail messages.

"Perhaps the most interesting part was the operating system, PenPoint OS, created by GO Corporation. Widely praised for its simplicity and ease of use, the OS never gained widespread use. Also equally compelling was the tightly integrated applications suite, Perspective, licensed to EO by Pensoft" (Wikipedia article on EO Personal Communicator, accessed 02-03-2010).

Ken Maki, The AT&T EO Travel Guide. (1993).

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The "TOP500" Ranking of Supercomputers June 1993

In June 1993 Hans Meuer of the University of Mannheim,Germany, Jack Dongarra of the University of Tennessee, Knoxville, and Erich Strohmaier and Horst Simon of NERSC / Lawrence Berkeley National Laboratory began the compilation of the TOP500 project, ranking the 500 most powerful (non-distributedcomputer systems. The project  published an updated list of the supercomputers twice a year. The first of these updates always coincided with the International Supercomputing Conference in June, and the second one was presented in November at the ACM/IEEE Supercomputing Conference.

The project aimed to provide a reliable basis for tracking and detecting trends in high-performance computing and bases rankings on HPL, a portable implementation of the high-performance LINPACK benchmark, written in Fortran for distributed-memory computers.

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Supercomputer ASCI Blue-Pacific SST October 28, 1998

On October 28, 12998 supercomputer ASCI Blue-Pacific SST, jointly developed by the U.S. Energy Department’s Lawrence Livermore National Laboratory and IBM, could perform 3.9 trillion calculations per second (15,000 times faster than the average desktop computer) and had over 2.6 trillion bytes of memory (80,000 times more than the average PC).

IBM commented that it would take a person using a calculator 63,000 years to perform as many calculations as this computer could perform in a single second.

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IBM's Blue Gene Project Begins December 1999

In December 1999 IBM announced the start of a five-year effort to build a massively parallel computer, Blue Gene, the study of bio-molecular phenomena such as protein folding. When the project began Blue Gene was 500 times more powerful than the world’s fastest computers. 

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2000 – 2005

The ASCI White Supercomputer Becomes Operational June 29, 2000

A technician monitors IBM's ASCI White Supercomputer in 2000

The exterior patio of the National Ignition Facility at the Lawrence Livermore National Laboratory 

A sign outside the Lawrence Livermore National Laboratory

The ASCI White supercomputer at the Lawrence Livermore National Laboratory in California became operational on June 29, 2000. An IBM system, it covered a space the size of two basketball courts and weighed 106 tons. It contained six trillion bytes (TB) of memory— almost 50,000 times greater than the average personal computer at the time—and had more than 160 TB of Serial Disk System storage capacity—enough to hold six times the information stored in the 29 million books in the Library of Congress.

♦ In December 2013 I decided that the ASCI White would be the last supercomputer documented in From Cave Paintings to the Internet. The merits of supercomputers are mainly appreciated for their abilities to perform the most complex of calculations, and without the time and space and the ability to explain such calculations, descriptions of the ever-advancing magnitudes of supercomputers seemed beyond the scope of this project. Readers can follow the development of supercomputers through the Wikipedia article on supercomputer and through other websites, such as the TOP500 twice-annual ranking of the world's supercomputers. To review progress to 2000 and a bit afterward, I quote the section on Applications of Supercomputers from the Wikipedia article as it read in December 2013:

"Applications of supercomputers

"The stages of supercomputer application may be summarized in the following table:

DecadeUses and computer involved
1970s Weather forecasting, aerodynamic research (Cray-1).
1980s Probabilistic analysis, radiation shielding modeling (CDC Cyber).
1990s Brute force code breaking (EFF DES cracker),
2000s 3D nuclear test simulations as a substitute for legal conduct Nuclear Non-Proliferation Treaty (ASCI Q).
2010s Molecular Dynamics Simulation (Tianhe-1A)

"The IBM Blue Gene/P computer has been used to simulate a number of artificial neurons equivalent to approximately one percent of a human cerebral cortex, containing 1.6 billion neurons with approximately 9 trillion connections. The same research group also succeeded in using a supercomputer to simulate a number of artificial neurons equivalent to the entirety of a rat's brain.

"Modern-day weather forecasting also relies on supercomputers. The National Oceanic and Atmospheric Administration uses supercomputers to crunch hundreds of millions of observations to help make weather forecasts more accurate."

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Babbage's Difference Engine No. 2 and its Printer are Finally Constructed 2002

Charles Babbage

The Babbage Difference Engine No. 2

The Science Museum, London

In 2002 Charles Babbage’s Difference Engine No. 2, designed between 1847 and 1849, but never previously built, was completed and fully operational at the Science Museum, London. Babbage's purpose in designing the machine was to produce mathematical tables more accurate than any available in his day. To this end he designed a machine that could not only compute the tables but could also print them out and prepare stereotype printing plates so that the tables could be printed without the insertion of errors by human typesetters.

Built from Babbage’s engineering drawings roughly 150 years after it was originally designed, the calculating section of the machine weighs 2.6 tons and consists of 4000 machined parts. The automatic printing and stereotyping apparatus weighs an equal amount, with about the same number of parts. The machine is operated by turning hand-cranks.

The calculating section of the machine was completed in November 1991.  After the Science Museum successfully built the computing section Nathan Myhrvold funded the construction of the output section, which performs both printing and stereotyping of calculated results. He also commissioned the construction of a second complete Difference Engine #2 for himself, which has been on display at the Computer History Museum in Mountain View, California, since May 10, 2008.

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2005 – 2010

Publishing Patent Filings on the Web September 26, 2006

The IBM logo

IBM, the largest patent holder in the U.S., announced on September 26, 2006 that it would publish its patent filings on the Web for public review, as part of a new policy that the company hoped would be a model for others.

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Steve Jobs Introduces the iPhone June 29, 2007

The iPhone 3G

On June 29, 2007 Apple introduced the iPhone, an internet-connected multimedia smartphone with a virtual keypad and a virtual keyboard.

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The SyNAPSE Neuromorphic Machine Technology Project Begins 2008

Traditional stored-program von Neumann computers are constrained by physical limits, and require humans to program how computers interact with their environments. In contrast the human brain processes information autonomously, and learns from its environment. Neuromorphic electronic machines— computers that function more like a brain— may enable autonomous computational solutions for real-world problems with many complex variables. In 2008 DARPA awarded the first funding to HRL Laboratories, Hewlett-Packard and IBM Research for SyNAPSE (Systems of Neuromorphic Adaptive Plastic Scalable Electronics)—an attempt to build a new kind of cognitive computer with form, function and architecture similar to the mammalian brain. The program sought to create electronic systems inspired by the human brain that could understand, adapt and respond to information in ways fundamentally different from traditional computers.

"The initial phase of the SyNAPSE program developed nanometer scale electronic synaptic components capable of adapting the connection strength between two neurons in a manner analogous to that seen in biological systems (Hebbian learning), and simulated the utility of these synaptic components in core microcircuits that support the overall system architecture" (Wikipedia article on SyNAPSE, accessed 10-20-2013).

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2010 – 2012

Steve Jobs Introduces the iPad, the First Widely Sold Tablet Computer January 27, 2010

On January 27, 2010 Steve Jobs of Apple introduced the iPad, the first widely sold tablet computer. The first iPad was one-half inch thick, with a 9.7 inch, high resolution color touchscreen (multi-touch) diagonal display, powered by a 1-gigahertz Apple A4 chip and 16 to 64 gigabytes of flash storage, weighing 1.5 pounds and capable of running all iPhone applications, except presumably, the phone. The battery life was supposed to be 10 hours, and the device was supposed to hold a charge for 1 month in standby. The price started at $499.00.

"The new device will have to be far better than the laptop and smartphone at doing important things: browsing the Web, doing e-mail, enjoying and sharing photographs, watching videos, enjoying your music collection, playing games, reading e-books. Otherwise, 'it has no reason for being.'" (http://bits.blogs.nytimes.com/2010/01/27/live-blogging-the-apple-product-announcement/?hp, accessed 01-27-2010).

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Apple 1 Computers Sell for $210,000 in 2010, for $671,400 in 2013, for $905,000 and $365,000 in 2014 November 23, 2010 – October 22, 2014

An original Apple 1 personal computer in excellent condition but with a few later modifications, sold for 110,000 pounds or $174,000 hammer at a Christie's book and manuscript auction in London. (Christie's sale 7882, lot 65).

Associated Press reported that the purchaser was businessman and collector Marco Boglione of Torino, Italy, who bid by phone. His total cost came to 133,250 pounds or about $210,000 after the buyer's premium. Prior to the auction, Christie's estimated the computer would sell for between $160,000-$240,000. When it was released in 1976, the Apple I sold for $666.66.

Only about 200 Apple 1's were built, of which perhaps "30 to 50" remain in existence. The auctioned example came in its original box with a signed letter from Apple cofounder Steve Jobs.

Apple cofounder Steve Wozniak, who hand-built each of the Apple 1's, attended the auction, and offered to autograph the computer.  

See also: http://www.mercurynews.com/news/ci_16695428?source=rss&nclick_check=1, accessed 11-23-2010.

At Sotheby's in 2012 another Apple 1 sold for $374,500. In November 2012 still another Apple 1 sold for $640,000 at Auction Team Breker in Cologne, Germany.

On May 25, 2013 Uwe Breker auctioned another Apple 1 for $671,400.

On October 22, 2014 Bonhams in New York sold another Apple 1 for $905,000. The buyer was the Henry Ford Museum in Deerborn Michigan. "In addition to the beautifully intact motherboard, this Apple-1 comes with a vintage keyboard with pre-7400 series military spec chips, a vintage Sanyo monitor, a custom vintage power supply in wooden box, as well as two vintage tape-decks. The lot additionally includes ephemera from the Cincinnati AppleSiders such as their first newsletter "Poke-Apple" from February of 1979 and a video recording of Steve Wozniak's keynote speech at the 1980 'Applevention.' "

On December 11 Christie's in New York offered The Ricketts’ Apple-1 Personal Computer in an online auctionNamed after its first owner Charles Ricketts, this example was the only known surviving Apple-1 documented to have been sold directly by Steve Jobs to an individual from his parents’ garage.

"23 years after Ricketts bought the Apple-1 from Jobs in Los Altos, it was acquired by Bruce Waldack, a freshly minted entrepreneur who’d just sold his company DigitalNation.  The Ricketts Apple-1 was auctioned at a sheriff’s sale of Waldack’s property at a self-storage facility in Virginia in 2004, and won by the present consigner, the American collector, Bob Luther.

  • The Ricketts Apple-1 is fully operational, having been serviced and started by Apple-1 expert Corey Cohen in October 2014. Mr. Cohen ran the standard original software program, Microsoft BASIC, and also an original Apple-1 Star Trek game in order to test the machine.
  • The computer will be sold with the cancelled check from the original garage purchase on July 27, 1976 made out to Apple Computer by Charles Ricketts for $600, which Ricketts later labeled as “Purchased July 1976 from Steve Jobs in his parents’ garage in Los Altos”. 
  • A second cancelled check for $193 from August 5, 1976 is labeled “Software NA Programmed by Steve Jobs August 1976”. Although Jobs is not usually thought of as undertaking much of the programming himself, many accounts of the period place him in the middle of the action, soldering circuits and clearly making crucial adjustments for close customers, as in this case.
  • These checks were later used as part of the evidence for the City of Los Altos to designate the Jobs family home at 2066 Crist Drive as a Historic Resource, eligible for listing on the National Register of Historic Places, and copies can be found in the Apple Computer archives at Stanford University Libraries."

The price realized was $365,000, which was, of course, diaappointing compared to the much higher price realized on Bonhams only two months earlier.

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The Smartphone Becomes the CPU of the Laptop January 2011

Motorola Mobility, headquartered in Libertyville, Illinois, introduced the Atrix 4G smartphone powered by Nvidia's Tegra 2 dual-core  processor and Android 2.2, with a 4-inch display, 1 GB of RAM, 16 GB of on-board storage, front- and rear-facing cameras, a 1930 mAh battery and a fingerprint reader. Motorola announced that it would also sell laptop and desktop docks that run a full version of Firefox, powered entirely by the phone.

What was significant about this smartphone was that the phone could do the information processing for the laptop or even the desktop interfaces.

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Koomey’s Law of Electrical Efficiency in Computing March 2011

Energy and environmental scientist Jonathan Koomey of Stanford University, and Stephen Berard, Maria Sanchez, and Henry Wong published “Implications of Historical Trends in the Electrical Efficiency of Computing” Annals of the History of Computing, 33, no. 3, 46-54. This historical paper was highly unusual for its enunciation of a predictive trend in computing technology labeled by the press as “Koomey’s Law.”

“Koomey’s law describes a long-term trend in the history of computing hardware. The number of computations per joule of energy dissipated has been doubling approximately every 1.57 years. This trend has been remarkably stable since the 1950s (R2 of over 98%) and has actually been somewhat faster than Moore’s law. Jon Koomey articulated the trend as follows: ‘at a fixed computing load, the amount of battery you need will fall by a factor of two every year and a half.’

Because of Koomey’s law, the amount of battery needed for a fixed computing load will fall by factor of 100 every decade. As computing devices become smaller and more mobile, this trend may be even more important than improvements in raw processing power for many applications. Furthermore, energy costs are becoming an increasingly important determinant of the economics of data centers, further increasing the importance of Koomey’s law” (Wikipedia article on Koomey's Law accessed 11-19-2011).

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The First Neurosynaptic Chips August 2011

In August 2011, as part of the SyNAPSE (Systems of Neuromorphic Adaptive Plastic Scalable Electronics) project, IBM researchers led by Dharmendra S. Modha, manager and lead researcher of the Cognitive Computing Group at IBM Almaden Research Center, demonstrated two neurosynaptic cores that moved beyond von Neumann architecture and programming to ultra-low, super-dense brain-inspired cognitive computing chips. These new silicon, neurosynaptic chips would be the building blocks for computing systems that emulate the brain's computing efficiency, size and power usage.

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Toward Cognitive Computing Systems August 18, 2011

On August 18, 2011 "IBM researchers unveiled a new generation of experimental computer chips designed to emulate the brain’s abilities for perception, action and cognition. The technology could yield many orders of magnitude less power consumption and space than used in today’s computers. 

"In a sharp departure from traditional concepts in designing and building computers, IBM’s first neurosynaptic computing chips recreate the phenomena between spiking neurons and synapses in biological systems, such as the brain, through advanced algorithms and silicon circuitry. Its first two prototype chips have already been fabricated and are currently undergoing testing.  

"Called cognitive computers, systems built with these chips won’t be programmed the same way traditional computers are today. Rather, cognitive computers are expected to learn through experiences, find correlations, create hypotheses, and remember – and learn from – the outcomes, mimicking the brains structural and synaptic plasticity.  

"To do this, IBM is combining principles from nanoscience, neuroscience and supercomputing as part of a multi-year cognitive computing initiative. The company and its university collaborators also announced they have been awarded approximately $21 million in new funding from the Defense Advanced Research Projects Agency (DARPA) for Phase 2 of the Systems of Neuromorphic Adaptive Plastic Scalable Electronics (SyNAPSE) project.

"The goal of SyNAPSE is to create a system that not only analyzes complex information from multiple sensory modalities at once, but also dynamically rewires itself as it interacts with its environment – all while rivaling the brain’s compact size and low power usage. The IBM team has already successfully completed Phases 0 and 1.  

" 'This is a major initiative to move beyond the von Neumann paradigm that has been ruling computer architecture for more than half a century,' said Dharmendra Modha, project leader for IBM Research. 'Future applications of computing will increasingly demand functionality that is not efficiently delivered by the traditional architecture. These chips are another significant step in the evolution of computers from calculators to learning systems, signaling the beginning of a new generation of computers and their applications in business, science and government.' " (http://www-03.ibm.com/press/us/en/pressrelease/35251.wss, accessed 08-21-2011).

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Steve Jobs Dies October 5, 2011

Steve Jobs, one of the most influential and daring innovators in the history of media, and arguably the most innovative and influential figure in the computer industry since the development of the personal computer, died at the age of 55 after a well-publicized battle with pancreatic cancer. Responsible, as inspirational leader, for building the first commercially successful personal computer (Apple II), for developing and popularizing the graphical user interface (Macintosh) which made personal computers user friendly, for developing desktop publishing, for making music truly portable (iPod, iTunes), for bringing all the elements of the personal computer to cell phones (iPhone), for causing the widespread acceptance of tablet computers (iPad), Jobs not only rescued Apple Computer from near failure and made it for a time the most valuable company in the S&P 500, but also achieved great success through his ownership of Pixar Animation Studios, which he eventually sold to The Walt Disney Company. Characteristics of Jobs' style were exceptional boldness in the conception of products, high quality and ease of use, and elegance of industrial design.

"Mr. Jobs even failed well. NeXT, a computer company he founded during his years in exile from Apple, was never a commercial success. But it was a technology pioneer. The World Wide Web was created on a NeXT computer, and NeXT software is the core of Apple’s operating systems today" (http://www.nytimes.com/2011/10/09/business/steve-jobs-and-the-power-of-taking-the-big-chance.html?hp).

An article published in The New York Times on October 8, 2011 compared and contrasted the lives and achievements of Steve Jobs with that earlier great American inventor and innovator, Thomas Alva Edison.

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2012 – 2015

Windows 8, With Touch Screen Features, is Released October 26, 2012

On October 26, 2012 Microsoft released the Windows 8 operating system to the general public. Development of Windows 8 started in 2009 before the release of its predecessor, Windows 7, the last iteration of Windows designed primarily for desktop computers. Windows 8 introduced very significant changes primarily focused toward mobile devices, tablets and cell phones which use touch screens, and:

"to rival other mobile operating systems like Android and iOS, taking advantage of new or emerging technologies like USB 3.0, UEFI firmware, near field communications, cloud computing and the low-power ARM architecture, new security features such as malware filtering, built-in antivirus capabilities, a new installation process optimized for digital distribution, and support for secure boot (a UEFI feature which allows operating systems to be digitally signed to prevent malware from altering the boot process), the ability to synchronize certain apps and settings between multiple devices, along with other changes and performance improvements. Windows 8 also introduces a new shell and user interface based on Microsoft's "Metro" design language, featuring a new Start screen with a grid of dynamically updating tiles to represent applications, a new app platform with an emphasis on touchscreen input, and the new Windows Store to obtain and/or purchase applications to run on the operating system" (Wikipedia article on Windows 8, accessed 12-14-2012).

On December 13, 2012 MIT's technologyreview.com published an interview with Julie Larson-Green, head of product development at Microsoft, in which Larson-Green explained why Microsoft decided it was necessary to rethink and redesign in a relatively radical manner the operating system used by 1.2 billion people:

Why was it necessary to make such broad changes in Windows 8?

"When Windows was first created 25 years ago, the assumptions about the world and what computing could do and how people were going to use it were completely different. It was at a desk, with a monitor. Before Windows 8 the goal was to launch into a window, and then you put that window away and you got another one. But with Windows 8, all the different things that you might want to do are there at a glance with the Live Tiles. Instead of having to find many little rocks to look underneath, you see a kind of dashboard of everything that’s going on and everything you care about all at once. It puts you closer to what you’re trying to get done. 

Windows 8 is clearly designed with touch in mind, and many new Windows 8 PCs have touch screens. Why is touch so important? 

"It’s a very natural way to interact. If you get a laptop with a touch screen, your brain clicks in and you just start touching what makes it faster for you. You’ll use the mouse and keyboard, but even on the regular desktop you’ll find yourself reaching up doing the things that are faster than moving the mouse and moving the mouse around. It’s not like using the mouse, which is more like puppeteering than direct manipulation. 

In the future, are all PCs going to have touch screens? 

"For cost considerations there might always be some computers without touch, but I believe that the vast majority will. We’re seeing that the computers with touch are the fastest-selling right now. I can’t imagine a computer without touch anymore. Once you’ve experienced it, it’s really hard to go back.

Did you take that approach in Windows 8 as a response to the popularity of mobile devices running iOS and Android? 

"We started planning Windows 8 in June of 2009, before we shipped Windows 7, and the iPad was only a rumor at that point. I only saw the iPad after we had this design ready to go. We were excited. A lot of things they were doing about mobile and touch were similar to what we’d been thinking. We [also] had differences. We wanted not just static icons on the desktop but Live Tiles to be a dashboard for your life; we wanted you to be able to do things in context and share across apps; we believed that multitasking is important and that people can do two things at one time. 

Can touch coexist with a keyboard and mouse interface? Some people have said it doesn’t feel right to have both the newer, touch-centric elements and the old-style desktop in Windows 8. /

"It was a very definite choice to have both environments. A finger’s never going to replace the precision of a mouse. It’s always going to be easier to type on a keyboard than it is on glass. We didn’t want you to have to make a choice. Some people have said that it’s jarring, but over time we don’t hear that. It’s just getting used to something that’s different. Nothing was homogenous to start with, when you were in the browser it looked different than when you were in Excel."

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Memcomputing Outlined November 19, 2012

On November 19, 2012 physicists Massimiliano Di Ventra at the University of California, San Diego and Yuriy Pershin at the University of South Carolina, Columbia, outlined an emerging form of computation called memcomputing based on the discovery of nanoscale electronic components that simultaneously store and process information, much like the human brain.

At the heart of this new form of computing are nanodevices called the memristor, memcapacitor and meminductor, fundamental electronic components that store information while respectively operating as resistors, capacitors and inductors. These devices were predicted theoretically in the 1970s but first manufactured in 2008. Because these devices consume very little energy computers using them could approach the energy efficiency of natural systems such as the human brain for the first time.  

"In present day technology, storing and processing of information occur on physically distinct regions of space. Not only does this result in space limitations; it also translates into unwanted delays in retrieving and processing of relevant information. There is, however, a class of two-terminal passive circuit elements with memory, memristive, memcapacitive and meminductive systems – collectively called memelements – that perform both information processing and storing of the initial, intermediate and final computational data on the same physical platform. Importantly, the states of these memelements adjust to input signals and provide analog capabilities unavailable in standard circuit elements, resulting in adaptive circuitry, and providing analog massively-parallel computation. All these features are tantalizingly similar to those encountered in the biological realm, thus offering new opportunities for biologically-inspired computation. Of particular importance is the fact that these memelements emerge naturally in nanoscale systems, and are therefore a consequence and a natural by-product of the continued miniaturization of electronic devices. . . ." (Di Ventra & Pershin, "Memcomputing: a computing paradigm to store and process information on the same physical platform," http://arxiv.org/pdf/1211.4487v1.pdf, accessed 11-22-2012). 

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Crossbar Memory can Store a Terabyte on a Postage-Stamp Sized Chip August 2013

In August 2013 Technologyreview.com announced that a new type of memory chip developed by Wei Lu of the University of Michigan, and under development at Crossbar Inc. in Santa Clara, California, can store a terabyte of information on a postage-stamp sized CMOS compatible chip. Crossbar memory allows data storage at about 40 times the density of flash memory, and it is faster and more energy efficient.

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A New Software Ecosystem to Program SyNAPSE Chips August 8, 2013

August 8, 2013 Dharmendra S. Modha, senior manager and principal investigator at the Cognitive Computing Group at IBM Almaden Research Center, unveiled a new software ecosystem to program SyNAPSE chips, which "have an architecture inspired by the function, low power, and comptact volume of the brain." 

“ 'We are working to create a FORTRAN for synaptic computing chips. While complementing today’s computers, this will bring forth a fundamentally new technological capability in terms of programming and applying emerging learning systems.'

"To advance and enable this new ecosystem, IBM researchers developed the following breakthroughs that support all aspects of the programming cycle from design through development, debugging, and deployment: 

"-         Simulator: A multi-threaded, massively parallel and highly scalable functional software simulator of a cognitive computing architecture comprising a network of neurosynaptic cores.  

"-         Neuron Model: A simple, digital, highly parameterized spiking neuron model that forms a fundamental information processing unit of brain-like computation and supports a wide range of deterministic and stochastic neural computations, codes, and behaviors. A network of such neurons can sense, remember, and act upon a variety of spatio-temporal, multi-modal environmental stimuli. 

"-         Programming Model: A high-level description of a “program” that is based on composable, reusable building blocks called “corelets.” Each corelet represents a complete blueprint of a network of neurosynaptic cores that specifies a based-level function. Inner workings of a corelet are hidden so that only its external inputs and outputs are exposed to other programmers, who can concentrate on what the corelet does rather than how it does it. Corelets can be combined to produce new corelets that are larger, more complex, or have added functionality. 

"-         Library: A cognitive system store containing designs and implementations of consistent, parameterized, large-scale algorithms and applications that link massively parallel, multi-modal, spatio-temporal sensors and actuators together in real-time. In less than a year, the IBM researchers have designed and stored over 150 corelets in the program library.  

"-         Laboratory: A novel teaching curriculum that spans the architecture, neuron specification, chip simulator, programming language, application library and prototype design models. It also includes an end-to-end software environment that can be used to create corelets, access the library, experiment with a variety of programs on the simulator, connect the simulator inputs/outputs to sensors/actuators, build systems, and visualize/debug the results" (http://www-03.ibm.com/press/us/en/pressrelease/41710.wss, accessed 10-20-2013).

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The First Production-Scale Neuromorphic Computing Chip August 8, 2014

On August 8, 2014 scientists from IBM and Cornell University, including Paul A. MerollaJohn V. Arthur, Rodrigo Alvarez-Icaza, Andrew S. Cassidy, Jun Sawada, Filipp Akopyan, Bryan L. Jackson, and Dharmendra S. Modha, reported in the journal Science the first production-scale neuromorphic computing chip—a significant landmark in the development of cognitive computing. The chip, named TrueNorth, attempted to mimic the way brains recognize patterns, relying on densely interconnected webs of transistors similar to neural networks in the brain. It employed an efficient, scalable, and flexible non–von Neumann architecture. Von Neumann architecture, in which memory and processing were separated, and information flowed back and forth between the two components, remained the standard computer architecture from the design of the earliest electronic computers to 2014, so the new neuromorphic chip design represented a radical departure. 

"The chip contains 5.4 billion transistors, yet draws just 70 milliwatts of power. By contrast, modern Intel processors in today’s personal computers and data centers may have 1.4 billion transistors and consume far more power — 35 to 140 watts.

"Today’s conventional microprocessors and graphics processors are capable of performing billions of mathematical operations a second, yet the new chip system clock makes its calculations barely a thousand times a second. But because of the vast number of circuits working in parallel, it is still capable of performing 46 billion operations a second per watt of energy consumed, according to IBM researchers.

"The TrueNorth has one million 'neurons,' about as complex as the brain of a bee.

“ 'It is a remarkable achievement in terms of scalability and low power consumption,' said Horst Simon, deputy director of the Lawrence Berkeley National Laboratory.

"He compared the new design to the advent of parallel supercomputers in the 1980s, which he recalled was like moving from a two-lane road to a superhighway.

"The new approach to design, referred to variously as neuromorphic or cognitive computing, is still in its infancy, and the IBM chips are not yet commercially available. Yet the design has touched off a vigorous debate over the best approach to speeding up the neural networks increasingly used in computing.

"The idea that neural networks might be useful in processing information occurred to engineers in the 1940s, before the invention of modern computers. Only recently, as computing has grown enormously in memory capacity and processing speed, have they proved to be powerful computing tools" (John Markoff, "IBM Designs a New Chip that Functions Like A Brain," The New York Times, August 7, 2014).

Merolla et al, "A million spiking-neuron integrated circuit with a scalable communication network and interface," Science 345 no. 6197 (August 8, 2014) 668-673.

"Inspired by the brain’s structure, we have developed an efficient, scalable, and flexible non–von Neumann architecture that leverages contemporary silicon technology. To demonstrate, we built a 5.4-billion-transistor chip with 4096 neurosynaptic cores interconnected via an intrachip network that integrates 1 million programmable spiking neurons and 256 million configurable synapses. Chips can be tiled in two dimensions via an interchip communication interface, seamlessly scaling the architecture to a cortexlike sheet of arbitrary size. The architecture is well suited to many applications that use complex neural networks in real time, for example, multiobject detection and classification. With 400-pixel-by-240-pixel video input at 30 frames per second, the chip consumes 63 milliwatts" (Abstract).

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