Evolution of Computers Difference Engine,Mark-I,Von Neumann,ENIAC,EVAC

Evolution of Computers 

Difference Engine,Mark-I,Von Neumann,ENIAC,EVAC

The computer that we use today is the result of man’s long search for a  device to help in performing computations mechanically. The search dates back to the 17^th century . A series of scientific breakthrough by many scientists have contributed to produce this electronic machine called the computer.

• If we look back at the history of computers. It can be traced back to 3000 B.C. The stone age man used small round stones  (pebbles) for counting cattle.

• Movable beads on a wire-frame constituted the first known calculating device called abacus. The abacus was used by the ancient Greeks and Romans, although significant contributions to its design were made by the Chinese. The Chinese abacus is called Suan Pan, which means counting-board. Beads are stored at one side of the frame, and calculations are performed at the other side by moving beads against that side of the frame. The significant conceptual contribution of the abacus is the use of position to represent value.

•  Mechanical Calculators- In 1642, Blaise Pascal, a French mathematician invented the first mechanical calculator. This machine is also called as Pascaline. Pascal developed a gear driven machine capable of addition, subtraction and multiplication. Manipulations were performed by rotating wheels, and a  mechanism made possible an automatic carry. The automatic carry was the significant contribution from Pascal’s machine.

            In 1671, a German mathematician Gottfried Von Leibnitz improved Pascal’s design and built a machine that multiplied, divided and determined square roots. This calculator  consisted of a cylindrical drum with several teeth along its surface. The teeth varied in length, and when the drum rotated, some of them engaged in sliding gear on the axie. This gear principle was employed in many mechanical calculators until they were replaced by electronic calculators in the 1960’s.

Jacquard's Loom

In 1801, a Frenchman named Joseph Jacquard perfected a loom that was controlled by the holes in a cardboard punched cards. The design  for woven fabric was represented by a series of holes punched in the card. In the loom’s control mechanism, mechanical fingers were activated by the presence or absence of a hole in the card. The movement of the fingers determined what threads  were to appear in the fabric. By sequencing  the cards, the loom could produce a large number of patterns and designs. When the cards for a particular pattern was automatically replaced. Jacquard’s punched were , in effect a program for the loom . There is a similarity between Jacquard’s cards and stored programs in a computer.

Charles Babbage's Difference Engine In 1812, Charles Babbage , an English  mathematician and inventor, found that certain principles from Jacquard’s loom could be used in numerical computation. Babbage called his first machine a Difference Engine and designed it to calculate logarithm tables. A series of levers were used to enter the data, and a device similar to the typewriter was used to print the output.                In 1833, Charles Babbage designed an advance form of Difference Engine called as an Analytical Engine. It was designed to add, subtract, multiply and divide through the use of a stored program . The four major components of Analytical Engine were input and output devices, an arithmetic unit to perform the calculations and a memory to store the intermediate calculations. Modern computers are based on Analytical Engine, Therefore, Charles Babbage is known as the Father of Computer.             A significant contributor to Babbage’s research was Auguta Ada Byron. Ada Byron was an accomplished mathematician who recorded and analyzed many of Babbage’s ideas. Because of her work in developing the mathematician tables, for the Analytical Engine, she is recognized as first programmer. Hollerith Census Tabulator             Herman Hollerith designed a device called the Tabulating machine, which used machine readable punched cards. Initially, Hollerith’s cards had round holes and 45 columns. His machine reduced tabulating time in 1890 census to one-eighth the time required by old methods. Hollerith founded the Tabulating Machine Company in 1896 to manufacture and sell his new inventions. In 1911, the Tabulating Machine Company merged with the International Time Recording Company , the Dayton Seale Company, and the Bundy Manufacturing Corporation to form the Computing Tabulating Recording Company (CTR). CTR was renamed as International Business Machine Corporation (IBM) in 1924.             The ATANASOFF-BERRY Computer (1939-42) – This electronic machine ws developed by Dr. John Atanasoff to solve certain mathematical equations. It was called the Atanasoff-Berry computer, or ABC , after its Inventor’s name and his assistant, Clifford Berry. It used 45 vaccuum tubes for internal logic and capacitors for storage.  Aiken and Mark-I (1937-44) In 1944, Dr. Howard Aiken developed a machine called as Automatic Sequence Controlled Calculator which was later named as Mark-I             Mark-I was complex in design and huge in size. Physically, the machine measured  51 feet in length  and 8 feet in height. It is said to have contained three-quarters of a million parts and more than 5 hundred miles of wire in construction. It was extremely slow by present day standards. The addition of numbers took 0.3 part of a second and multiplication 4.5 seconds. The mark-I  was really an electro-mechanical  machine as its CPU depended on both mechanical and electronic devices for its operation. Von Neumann In1945, a significant contribution was made by John Von Neumann , a Frenchman working for IBM. He designed the basic structure of a computer to include the capacity to: Perform logical functions Perform repetitive functions Store data and instructions ENIAC (1943-46) In 1945, the fully electronic computer named ENIAC was built by Presper Eckert and John W. Mauchly. ENIAC stands for Electronic Numerical Integrator and Calculator.             It uses high speed vacuum tube switching devices. The machine was small in terms of storage capacity and as it was designed for a specific purpose (ballistics), and its use was limited. EDVAC (1946-52) The operation of ENIAC was seriously handicapped by the wiring board. This problem was later overcome by the new concept of “stored program” developed by Dr. John Von Neumann. The basic idea behind the stored program concept is that a sequence of instructions as well as data can be stored in the memory of the computer for the purpose of automatically directing the flow of operations. Von Neumann has also got a share of the credit for introducing the idea of storing both instructions and data in the binary form (a system that uses only two digits -0 and 1 to represent all characters) instead of the decimal numbers or human readable words.