**The Mechanical
Era**

**(1623-1945)**

The idea of using machines to solve mathematical problems can be traced at least as far as the early 17th century. Mathematicians who designed and implemented calculators that were capable of addition, subtraction, multiplication, and division included Wilhelm Schickhard, Blaise Pascal, and Gottfried Leibnitz.

The first multipurpose, i.e. programmable, computing device was probably Charles Babbage's Difference Engine, which was begun in 1823 but never completed. A more ambitious machine was the Analytical Engine. It was designed in 1842, but unfortunately it also was only partially completed by Babbage. Babbage was truly a man ahead of his time: many historians think the major reason he was unable to complete these projects was the fact that the technology of the day was not reliable enough. In spite of never building a complete working machine, Babbage and his colleagues, most notably Ada, Countess of Lovelace, recognized several important programming techniques, including conditional branches, iterative loops and index variables.

**Abacus**

A machine inspired by Babbage's design was arguably the first to be used in computational science. George Scheutz read of the difference engine in 1833, and along with his son Edvard Scheutz began work on a smaller version. By 1853 they had constructed a machine that could process 15-digit numbers and calculate fourth-order differences. Their machine won a gold medal at the Exhibition of Paris in 1855, and later they sold it to the Dudley Observatory in Albany, New York, which used it to calculate the orbit of Mars. One of the first commercial uses of mechanical computers was by the US Census Bureau, which used punch-card equipment designed by Herman Hollerith to tabulate data for the 1890 census. In 1911 Hollerith's company merged with a competitor to found the corporation which in 1924 became International Business Machines.

**Early Computing
Machines and Inventors **

The abacus, which emerged about 5,000 years ago in Asia Minor and is still in use today, may be considered the first computer. This device allows users to make computations using a system of sliding beads arranged on a rack. Early merchants used the abacus to keep trading transactions. But as the use of paper and pencil spread, particularly in Europe, the abacus lost its importance. It took nearly 12 centuries, however, for the next significant advance in computing devices to emerge. In 1642, Blaise Pascal (1623-1662), the 18-year-old son of a French tax collector, invented what he called a numerical wheel calculator to help his father with his duties. This brass rectangular box, also called a Pascaline, used eight movable dials to add sums up to eight figures long. Pascal's device used a base of ten to accomplish this. For example, as one dial moved ten notches, or one complete revolution, it moved the next dial - which represented the ten's column - one place. When the ten's dial moved one revolution, the dial representing the hundred's place moved one notch and so on. The drawback to the Pascaline, of course, was its limitation to addition.

In 1694, a German mathematician and philosopher, Gottfried Wilhem von Leibniz (1646-1716), improved the Pascaline by creating a machine that could also multiply. Like its predecessor, Leibniz's mechanical multiplier worked by a system of gears and dials. Partly by studying Pascal's original notes and drawings, Leibniz was able to refine his machine. The centerpiece of the machine was its stepped-drum gear design, which offered an elongated version of the simple flat gear. It wasn't until 1820, however, that mechanical calculators gained widespread use. Charles Xavier Thomas de Colmar, a Frenchman, invented a machine that could perform the four basic arithmetic functions. Colmar's mechanical calculator, the arithometer, presented a more practical approach to computing because it could add, subtract, multiply and divide. With its enhanced versatility, the arithometer was widely used up until the First World War. Although later inventors refined Colmar's calculator, together with fellow inventors Pascal and Leibniz, he helped define the age of mechanical computation.

The real beginnings of computers as we know them today, however, lay with an English mathematics professor, Charles Babbage (1791-1871). Frustrated at the many errors he found while examining calculations for the Royal Astronomical Society, Babbage declared, "I wish to God these calculations had been performed by steam!" With those words, the automation of computers had begun. By 1812, Babbage noticed a natural harmony between machines and mathematics: machines were best at performing tasks repeatedly without mistake; while mathematics, particularly the production of mathematic tables, often required the simple repetition of steps. The problem centered on applying the ability of machines to the needs of mathematics. Babbage's first attempt at solving this problem was in 1822 when he proposed a machine to perform differential equations, called a Difference Engine. Powered by steam and large as a locomotive, the machine would have a stored program and could perform calculations and print the results automatically. After working on the Difference Engine for 10 years, Babbage was suddenly inspired to begin work on the first general-purpose computer, which he called the Analytical Engine. Babbage's assistant, Augusta Ada King, Countess of Lovelace (1815-1842) and daughter of English poet Lord Byron, was instrumental in the machine's design. One of the few people who understood the Engine's design as well as Babbage, she helped revise plans, secure funding from the British government, and communicate the specifics of the Analytical Engine to the public. Also, Lady Lovelace's fine understanding of the machine allowed her to create the instruction routines to be fed into the computer, making her the first female computer programmer. In the 1980's, the U.S. Defense Department named a programming language ADA in her honor.

**Babbage's Difference Engine **

Babbage's steam-powered Engine, although ultimately never constructed, may seem primitive by today's standards. However, it outlined the basic elements of a modern general purpose computer and was a breakthrough concept. Consisting of over 50,000 components, the basic design of the Analytical Engine included input devices in the form of perforated cards containing operating instructions and a "store" for memory of 1,000 numbers of up to 50 decimal digits long. It also contained a "mill" with a control unit that allowed processing instructions in any sequence, and output devices to produce printed results. Babbage borrowed the idea of punch cards to encode the machine's instructions from the Jacquard loom. The loom, produced in 1820 and named after its inventor, Joseph-Marie Jacquard, used punched boards that controlled the patterns to be woven.

In 1889, an American inventor, Herman Hollerith (1860-1929), also applied the Jacquard loom concept to computing. His first task was to find a faster way to compute the U.S. census. The previous census in 1880 had taken nearly seven years to count and with an expanding population, the bureau feared it would take 10 years to count the latest census. Unlike Babbage's idea of using perforated cards to instruct the machine, Hollerith's method used cards to store data information which he fed into a machine that compiled the results mechanically. Each punch on a card represented one number, and combinations of two punches represented one letter. As many as 80 variables could be stored on a single card. Instead of ten years, census takers compiled their results in just six weeks with Hollerith's machine. In addition to their speed, the punch cards served as a storage method for data and they helped reduce computational errors. Hollerith brought his punch card reader into the business world, founding Tabulating Machine Company in 1896, later to become International Business Machines (IBM) in 1924 after a series of mergers. Other companies such as Remington Rand and Burroghs also manufactured punch readers for business use. Both business and government used punch cards for data processing until the 1960's.

In the ensuing years, several engineers made other significant advances. Vannevar Bush (1890-1974) developed a calculator for solving differential equations in 1931. The machine could solve complex differential equations that had long left scientists and mathematicians baffled. The machine was cumbersome because hundreds of gears and shafts were required to represent numbers and their various relationships to each other. To eliminate this bulkiness, John V. Atanasoff (b. 1903), a professor at Iowa State College (now called Iowa State University) and his graduate student, Clifford Berry, envisioned an all-electronic computer that applied Boolean algebra to computer circuitry. This approach was based on the mid-19th century work of George Boole (1815-1864) who clarified the binary system of algebra, which stated that any mathematical equations could be stated simply as either true or false. By extending this concept to electronic circuits in the form of on or off, Atanasoff and Berry had developed the first all-electronic computer by 1940. Their project, however, lost its funding and their work was overshadowed by similar developments by other scientists.

**Year wise summery of development
**

1623:Wilhelm Schickard,invented First automatic
adding machine, Sized gears with 10 sprockets. When you turned the gear 10 times
it would force the next gear to turn.

1624: Wilhelm Schickard builds first four-function calculator-clock at the University of Heidelberg.

1642: Blaise Pascal builds the first numerical calculating machine calles the "Pascalene,"in Paris,very similar to Schickard's machine

1666 : In England, Samuel Morland produces a mechanical calculator that can add and subtract

1673: Gottfried Leibniz builds a mechanical calculating machine that multiplies, divides, adds and subtracts, Used the binary number system.

1674:Gottfried Leibnitz builds the "Stepped Reckoner," a calculator using a stepped cylindrical gear.

1774: Philipp-Matthaus Hahn builds and sells a small number of calculating machines precise to 12 digits.

1775: Charles Earl Stanhope makes a multiplying
calculator similar to Leibniz's.

1777 : The third Earl of Stanhope invents a multiplying calculator.

1786: J. H. Mueller conceives the idea of what
came to be called a "difference engine".

1780: American Benjamin Franklin discovers electricity.

1801: A linked sequence of punched
cards controls the weaving of patterns in Joseph-Marie Jacquard's loom.

1805: Joseph-Marie Jacquard invents perforated
card for use on his loom. Loom controlled with punch cards

A series of punch cards controlled the action of a loom. For a new pattern,
a new set of cards.

1811: Luddites destroy machinery that threatens
to eliminate jobs.

1820: The Thomas Arithmometer, based on Leibniz' stepped-drum principle, is
demonstrated to the French Academy of Science. It becomes the first mass-produced
calculator and sells for many years.

1822: In England Charles Babbage designs a Difference Engine to calculate logarithms, but the machine is never built. Concepts that Babbage never brought to fruition, the difference engine and the improved analytical engine were to be driven by a program on punched cards.

1829: William Austin Burt patents an awkward but workable typewriter, the first writing machine in America.

1832: Babbage and Joseph Clement produce a portion(produce
a prototype segment) of the Difference Engine.

1833: Charles Babbage designs the Analytical Machine that follows instructions from punched-cards. It is the first general purpose computer.

1834:George Scheutz, of Stockholm, produces a
small difference engine in wood.Babbage conceives, and begins to design, his
"Analytical Engine".

1838: In January Samuel Morse and Alfred Vail demonstrate elements of the telegraph system.

1842: Lady Ada Byron, Countess of Lovelace and daughter of Lord Byron, the poet, documents Babbage's work and writes programs for Babbage. Babbage's difference engine project is officially canceled.

1843: Scheutz and his son produce a 3rd-order difference engine with printer.

1844: Samuel Morse sends a telegraph message
from Washington to Baltimore.

1847 - 49: Babbage completes 21 drawings for the second version of the Difference
Engine but does not complete construction.

1850:George Boole,Creates Boolean logic

1850: Ada Byron, daughter of the poet Lord Byron,
created programs for Babbage's engine. Invented the subroutine.Got tired of
using repetitive stacks of cards, and invented the subroutine. Often considered
the mother of programming.

1853:The Scheutzes complete the first full-scale
difference engine.

1854: George Scheutz,Completes the difference engine

1854: Irishman George Boole publishes The Mathematical
Analysis of Logic using the binary system now known as Boolean algebra"An
Investigation of the Laws of Thought," describing a system for symbolic
and logical reasoning that will become the basis for computer design.

1855: George and Edvard Scheutz of Stockholm build the first practical mechanical computer based on Babbages work.

1858 : A telegraph cable spans the Atlantic Ocean
for the first time and provides service for a few days.

1861: A transcontinental telegraph line connects the Atlantic and Pacific coast.

1871: Babbage produces a prototype section of
the Analytical Engine's mill and printer.Charles Babbage dies.

1876: Alexander Graham Bell invents and patents the telephone.

1878: Ramon Verea invents a calculator with an internal multiplication table.

1879: A committee concludes that the Analytical Engine is impossible.

1882 : William S. Burroughs leaves his bank clerk's job determined to invent an adding machine.

1884: Institute of Electrical Engineers (IEE)
is founded. Herman Hollerith applies for patents for automatic punch-card tabulating
machine.

1885: A multiplying calculator enters mass production.

1886: Dorr E. Felt (1862-1930), of Chicago, makes
his "Comptometer". William Burroughs develops the first commercially
successful mechanical adding machine.

1888:Thomas Edison invented The Electric Chair.

1889: Felt invents the first printing desk. Patent
is issued for Hollerith tabulating machine. Herman Hollerith's Electric Tabulating
System outperforms the competitionand and in the fall is selected for use in
the 1890 census.

1890: Dr. Herman Hollerith constructs an electromechanical machine using perforated cards for use in the U.S. census.

1892: William S. Burroughs (1857-1898) starts
the office calculator industry.

1893 : The first four-function calculator is
invented.

1895 : Guglielmo Marconi transmitts a radio signal.

1896: Hollerith founds the Tabulating Machine Co. and constructs a sorting machine.

1901: The keypunch appears and changes very little over the next half century.

1903: Nikola Tesla, a Yugoslavian who worked for Thomas Edison, patents electrical logic circuits called gates or switches.

1904: John A.Fleming patents the diode vacuum
tube, setting the stage for better radio communication.

1906: Henry Babbage completes the mill of his father's Analytical Engine. :Lee de Forest adds a third valve to control current flow to Fleming's diode to create the three-electrode vacuum tube.

1907: Gramophone music constitutes the first regular radio broadcasts from New York.

1908: British scientist Campbell Swinton describes an electronic scanning method and foreshadows use of the cathode-ray tube for television.

1911: Hollerith's Tabulating Machines Co. ans two other companies combine to form C-T-R-Calculating, and Recording Co. Dutch physicist Kamerlingh Onnes at Leiden University discovers superconductivity

1912 : The Institute of Radio Engineers, which
will eventually merge with other organizations to form the IEEE, is established.

1914: Thomas J. Watson becomes President of Computing-Tabulating-Recording Company.

1915: Use of microchips is foreshadowed as physicist Manson Benedicks discovers that the germanium crystal can be used to convert alternating current to direct current.

1919: First flip-flop circuit design. .Eccles and Jordan, US physicists, invent the flip-flop electronic switching circuit critical to high-speed electronic counting systems.

1921: Czech word robot is used to describe mechanical workers in the play R.U.R. by Karel Capek.

1924: Computing-Tabulating-Recording Company
changes its name to International Business Machines, and popularizes the "Think"
slogan he coined at National Cash Register.

1925: Vannevar Bush, builds a large scale analog calculator, the differential analyzer, at MIT.

1927: First public demonstration of television. Radio-telephone becomes operational between London and New York. Powers Accounting Machine Company becomes the Tabulating Machines Division of Remington-Rand Corp. Herbert Hoover's face is seen on screen during the first demonstration of television in the US. Accompanying voice transmitting uses telephone wires.

1928: A Russian immigrant, Vladimir Zworykin, invents the cathode ray tube (CRT). The quartz crystal clock makes possible unprecedented time-keeping accuracy.

1929: Color television signals are successfully transmitted.

1930 : The Differential Analyzer, devised by
Vannnevar Bush and colleagues at MIT, solves various differential equations.

1931: First calculator, the Z1, is built in Germany by Konrad Zuse. Reynold B. Johnson a high school teacher in Michigan, devises a way to score mutiple-choice tests by sensing conductive pencil marks an answer sheets. IBM later buys the technology.

1933: First electronic talking machine, the Voder, is built by Dudley, who follows in 1939 with the Vocoder (Voice coder).

1934: In Germany, Konrad Zuse seeks to build
a better calculating machine than those currently available.

1935: International Business Machines introduces the "IBM 601" punch card machine.

1936: Englishman Alan M. Turing while at Princeton University formalizes the notion of calculableness and adapts the notion of algorithm to the computation of functions. Turing's machine is defined to be capable of computing any calculable function.

1937: George Stibitz builds the first binary calculator at Bell Telephone Laboratories.

1938: Hewlett-Packard Co. is founded to make
electronic equipment. Shannon publishes a paper on the implementation of symbolic
logic using relays.Zuse completes a prototype mechanical binary programmable
calculator, the Z1.

1939: First Radio Shack catalog is published. John J. Atanasoff designs a prototype for the ABC (Atanasoff-Berry Computer) with the help of graduate student Clifford Berry at Iowa State College. In 1973 a judge ruled it the first automatic digital computer. : Zuse and Schreyer begin work on the "V2" (later " Z2").John V. Atanasoff and Clifford Berry complete a prototype 16-bit adder.

1940: At Bell Labs, George Stibitz demonstrates the Complex Number Calculator, which may be the first digital computer. First color TV broadcast. Remote processing experiments, conducted by Bell Laboratories, create the first terminal.

1941: Colossus computer is designed by Alan M. Turing and built by M.H.A. Neuman at the University of Manchester, England. Konrad Zuse builds the Z3 computer in Germany, the first calculating machine with automatic control of its operations.

1943: On May 31, 1943, construction begins on the ENIAC at the Moore School of Electrical Engineering in Philadelphia.In December, Colossus, a British vacuum tube computer, becomes operational at Bletchley Park trough the combined efforts of Alan Turing, Tommy Flowers, and M.H.A Newman. It is considered the first all-electronic calculating device.

Howard H. Aiken and his team complete the "ASCC Mark I".Max Newman, Wynn-Williams, and their team complete the "Heath Robinson".Williams and Stibitz complete the "Relay Interpolator".Tommy Flowers and his team at Bletchley Park complete the first "Colossus".

1944: The Harvard Mark I (a.k.a. IBM Automatic Sequence controlled Calculator [ASCC]), produced by Howard Aiken, is dedicated at Harvard University on August 7, 1944. Colossus Mark II is built in England. 1944: Grace Murray Hopper starts a distinguished career in the computer industry by being the first programmer for the Mark I.

1945: By spring of the year, ENIAC is up and running. John von Neumann introduces the concept of a stored program in a June 30 draft report on the EDVAC design. Zuse's Z4 survives World War II and helps launch postwar development of scientific computers in Germany. Working on a prototype of the Mark II, in the summer Grace Murray Hopper finds the first computer "bug", a moth that had caused a relay failure. In July, Vannevar Bush's As We May Think is published in the Atlantic Monthly.

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