Wednesday 7 December 2011

EVOLUTION OF COMPUTERS

EVOLUTION OF COMPUTERS 







 

Computer - A Miracle


When men started to count the numbers, they thought of devices that can track of the numbers. The Abacus may be the first such device and it took hundreds of years to develop the Abacus to modern digital computer. The first computer origanated as an ordinary calculator in the 19th century.

ABACUS


The abacus, also called a counting frame, is a calculating tool used primarily in parts of Asia for performing arithmetic processes. Today, abaci are often constructed as a bamboo frame with beads sliding on wires, but originally they were beans or stones moved in grooves in sand or on tablets of wood, stone, or metal. The abacus was in use centuries before the adoption of the written modern numeral system and is still widely used by merchants, traders and clerks in Asia, Africa, and elsewhere. The user of an abacus is called an abacist.
  
 

EVOLUTION



ABACUS NAPIER'S BONES
 

Napier's bones


Napier's bones is an abacus created by John Napier for calculation of products and quotients of numbers that was based on Arab mathematics and lattice multiplication used by Matrakci Nasuh in the Umdet-ul Hisab and Fibonacci writing in the Liber Abaci. Also called Rabdology (from Greek ῥάβδoς [r(h)abdos], "rod" and -λογία [logia], "study"). Napier published his version of rods in a work printed in Edinburgh, Scotland, at the end of 1617 entitled Rabdologiæ. Using the multiplication tables embedded in the rods, multiplication can be reduced to addition operations and division to subtractions. More advanced use of the rods can even extract square roots. Note that Napier's bones are not the same as logarithms, with which Napier's name is also associated.
The abacus consists of a board with a rim; the user places Napier's rods in the rim to conduct multiplication or division. The board's left edge is divided into 9 squares, holding the numbers 1 to 9. The Napier's rods consist of strips of wood, metal or heavy cardboard. Napier's bones are three dimensional, square in cross section, with four different rods engraved on each one. A set of such bones might be enclosed in a convenient carrying case.
A rod's surface comprises 9 squares, and each square, except for the top one, comprises two halves divided by a diagonal line. The first square of each rod holds a single digit, and the other squares hold this number's double, triple, quadruple, quintuple, and so on until the last square contains nine times the number in the top square. The digits of each product are written one to each side of the diagonal; numbers less than 10 occupy the lower triangle, with a zero in the top half.
A set consists of 10 rods corresponding to digits 0 to 9. The rod 0, although it may look unnecessary, is obviously still needed for multipliers or multiplicands having 0 in them
 

Blaise Pascal


Blaise Pascal (French pronunciation:  [blɛz paskal] ; 19 June 1623 – 19 August 1662), was a French mathematician, physicist, inventor, writer and Catholic philosopher. He was a child prodigy who was educated by his father, a tax collector in Rouen. Pascal's earliest work was in the natural and applied sciences where he made important contributions to the study of fluids, and clarified the concepts of pressure and vacuum by generalizing the work of Evangelista Torricelli. Pascal also wrote in defense of the scientific method.
In 1642, while still a teenager, he started some pioneering work on calculating machines, and after three years of effort and 50 prototypes he invented the mechanical calculator. He built twenty of these machines (called the Pascaline) in the following ten years. Pascal was a mathematician of the first order. He helped create two major new areas of research. He wrote a significant treatise on the subject of projective geometry at the age of sixteen, and later corresponded with Pierre de Fermat on probability theory, strongly influencing the development of modern economics and social science. Following Galileo and Torricelli, in 1646 he refuted Aristotle's followers who insisted that nature abhors a vacuum. His results caused many disputes before being accepted.
In 1646, he and his sister Jacqueline identified with the religious movement within Catholicism known by its detractors as Jansenism . His father died in 1651. Following a mystical experience in late 1654, he had his "second conversion", abandoned his scientific work, and devoted himself to philosophy and theology. His two most famous works date from this period: the Lettres provinciales and the Pensées , the former set in the conflict between Jansenists and Jesuits. In this year, he also wrote an important treatise on the arithmetical triangle. Between 1658 and 1659 he wrote on the cycloid and its use in calculating the volume of solids.
Pascal had poor health especially after his eighteenth year and his death came just two months after his 39th birthday.
 

Blaise Pascal


Pascal's triangle. Each number is the sum of the two directly above it. The triangle demonstrates many mathematical properties in addition to showing binomial coefficients. Blaise Pascal PASCALINE
 

Analog computers

  
An analog computer is a form of computer that uses the continuously-changeable aspects of physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved. In contrast, digital computers represent varying quantities incrementally, as their numerical values change.
Mechanical analog computers were very important in gun fire control in World War II and the Korean War; they were made in significant numbers. In particular, development of transistors made electronic analog computers practical, and before digital computers had developed sufficiently, they were commonly used in science and industry.
Analog computers can have a very wide range of complexity. Slide rules and nomographs are the simplest, while naval gunfire control computers and large hybrid digital/analog computers were among the most complicated.
  

ANALOG COMPUTERS






Dr. Herman Hollerith

 

Dr. Herman Hollerith
 
 

Dr. Herman Hollerith


  • Herman Hollerith Herman Hollerith (February 29, 1860 – November 17, 1929) was an American statistician who developed a mechanical tabulator based on punched cards to rapidly tabulate statistics from millions of pieces of data. He was the founder of one of the companies that later merged and became IBM.
  • Personal life Hollerith was born in Buffalo, New York, where he spent his early childhood. He entered the City College of New York in 1875 and graduated from the Columbia University School of Mines with an "Engineer of Mines" degree in 1879. In 1880 he listed himself as a mining engineer while living in Manhattan, and completed his Ph.D. in 1890 at Columbia University. He eventually moved to Washington, D.C., living in Georgetown, with a home on 29th Street and ultimately a factory for manufacturing his tabulating machines at 31st Street and the C&O Canal, where today there is a commemorative plaque placed by IBM.
  • Electrical tabulation of data At the urging of John Shaw Billings,Hollerith developed a mechanism using electrical connections to trigger a counter,recording information.A key idea was that data could be coded numerically.Hollerith determined that if numbers could be punched in specified locations on a card,in the now-familiar rows and columns,then the cards could be counted or sorted mechanically and the data recorded.A description of this system,An Electric Tabulating System(1889),was submitted by Hollerith to Columbia University as his doctoral thesis,and is reprinted in Randell's book.On January 8,1889,Hollerith was issued U.S.Patent395,782,claim2 of which reads: The herein-described method of compiling statistics,which consists in recording separate statistical items pertaining to the individual by holes or combinations of holes punched in sheets of electrically non-conducting material, bearing a specific relation to each other and to a standard,then counting or tallying such statistical items separately.
  • Inventions and businesses Hollerith had left teaching and begun working for the United States Census Office in the year he filed his first patent application.Titled"Art of Compiling Statistics",it was filed on September 23,1884; U.S.Patent 395,782 was granted on January 8,1889.Patents 395,781 395,782 and 395,783 was published in the Scientific American on January 18,1889. Hollerith built machines under contract for the Census Office,which used them to tabulate the 1890 census in only one year.The 1880 census had taken eight years.Hollerith then started his own business in 1896,founding the Tabulating Machine Company.Most of the major census bureaus around the world leased his equipment and purchased his cards,as did major insurance companies.To make his system work,he invented the first automatic card-feed mechanism and the first key punch(that is,a punch operated by a keyboard);a skilled operator could punch 200–300 cards per hour.He also invented a tabulator.
 

GEORGE BOOLE


GEORGE BOOLE
 

George Boole


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THE FIRST PROGRAMMER


ADA AUGUSTA KING
 

THE FIRST PROGRAMMER


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THE DIFFERENCE ENGINE


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PUNCHED CARDS


PUNCHED CARDS JACQUARD
  

PUNCHED CARDS


A punched card, punch card, IBM card, or Hollerith card is a piece of stiff paper that contains digital information represented by the presence or absence of holes in predefined positions. Now an obsolete recording medium, punched cards were widely used throughout the 19th century for controlling textile looms and in the late 19th and early 20th century for operating fairground organs and related instruments. They were used through the 20th century in unit record machines for input, processing, and data storage. Early digital computers used punched cards, often prepared using keypunch machines, as the primary medium for input of both computer programs and data. Some voting machines use punched cards.
Punched cards were first used around 1725 by Basile Bouchon and Jean-Baptiste Falcon as a more robust form of the perforated paper rolls then in use for controlling textile looms in France. This technique was greatly improved by Joseph Marie Jacquard in his Jacquard loom in 1801.
Semen Korsakov was reputedly the first to use the punched cards in informatics for information store and search. Korsakov announced his new method and machines in September 1832, and rather than seeking patents offered the machines for public use.

Charles Babbage proposed the use of "Number Cards", "pierced with certain holes and stand opposite levers connected with a set of figure wheels ... advanced they push in those levers opposite to which there are no holes on the card and thus transfer that number" in his description of the Calculating Engine's Store.
Herman Hollerith invented the recording of data on a medium that could then be read by a machine. Prior uses of machine readable media, such as those above (other than Korsakov), had been for control, not data. "After some initial trials with paper tape, he settled on punched cards...", developing punched card data processing technology for the 1890 US census. He founded the Tabulating Machine Company (1896) which was one of four companies that merged to form Computing Tabulating Recording Corporation (CTR), later renamed IBM. IBM manufactured and marketed a variety of unit record machines for creating, sorting, and tabulating punched cards, even after expanding into electronic computers in the late 1950s. IBM developed punched card technology into a powerful tool for business data-processing and produced an extensive line of general purpose unit record machines. By 1950, the IBM card and IBM unit record machines had become ubiquitous in industry and government. "Do not fold, spindle or mutilate," a generalized version of the warning that appeared on some punched cards (generally on those distributed as paper documents to be later returned for further machine processing, checks for example), became a motto for the post-World War II era (even though many people had no idea what spindle meant).
From the 1900s, into the 1950s, punched cards were the primary medium for data entry, data storage, and processing in institutional computing. According to the IBM Archives: "By 1937... IBM had 32 presses at work in Endicott, N.Y., printing, cutting and stacking five to 10 million punched cards every day." Punched cards were even used as legal documents, such as U.S. Government checks and savings bonds. During the 1960s, the punched card was gradually replaced as the primary means for data storage by magnetic tape, as better, more capable computers became available. Punched cards were still commonly used for data entry and programming until the mid-1970s when the combination of lower cost magnetic disk storage, and affordable interactive terminals on less expensive minicomputers made punched cards obsolete for this role as well. However, their influence lives on through many standard conventions and file formats. The terminals that replaced the punched cards, the IBM 3270 for example, displayed 80 columns of text in text mode, for compatibility with existing software. Some programs still operate on the convention of 80 text columns, although fewer and fewer do as newer systems employ graphical user interfaces with variable-width type fonts.
Today punched cards are mostly obsolete and replaced with other storage methods, except for a few legacy systems and specialized applications.

DIGITAL ERA

CIRCUITS
CHIP

 

COMPUTER TRANSISTOR



DIGITAL ERA

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Transistors

A transistor is a semiconductor device used to amplify and switch electronic signals and power. It is composed of a semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current flowing through another pair of terminals. Because the controlled (output) power can be much more than the controlling (input) power, a transistor can amplify a signal. Today, some transistors are packaged individually, but many more are found embedded in integrated circuits.
The transistor is the fundamental building block of modern electronic devices, and is ubiquitous in modern electronic systems. Following its release in the early 1950s the transistor revolutionized the field of electronics, and paved the way for smaller and cheaper radios, calculators, and computers, among other things.