Evolution of computer.

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History of computer starts from that time when there were not any number systems discovered and there were no device for calculation. When men faced problems, newer and newer devices were developed, which are described as followings: 

1. Age of Mechanical Calculators :

a) Abacus : 

It was the earliest counting device. As show in the figure, it had two parts called heaven and earth. It could only add and subtract. It is believed to be discovered in China, Russia or Egypt.

b) John Napier and his rods :

Scottish mathematician John Napier invented a principle of calculation called logarithm in 1614 AD and based on the same principle he invented some bone rods engraved with numbers in 1617 AD, which was called Napier's Bone. With the help of this device, people could do multiplication very faster.

c) William Aughterd and his Slide Rule :

English mathematician William Augtherd discovered a device with two rulers fro calculation, which was based on Jhon Napier's principle but used only two rulers engraved with number in 1620 AD, which was called Slide Rule which we can see on figure. This device could perform multiplication and division and was the first analog device.

d) Blaise Pascal and his calculator :

France mathematician Blaise Pascal developed the first mechanical calculator in 1642 AD, which was called Pascal's Calculator. It had some cogs and gears rotating in complement to each other. It had a simple monitor to see the result. Calculation including addition and subtraction was possible up to 8 digits, which was a great achievement at that time. So, his work was honoured by Niklaus Writh by making a programming language called 'Pascal'.

e) G.V. Leibniz and his Stepped Reckoner :

 German mathematician Baron Gottfried Wilhelm Von Leibniz (in short we can say G.V. Leibniz) modified the pascal's machine and used the same principal to invent his new machine called Stepped Reckoner in 1671 AD. It could perform addition, subtraction, multiplication and division and could find out square root also for the fires time. It was used for calculation till 1960s before electronic or electromechanical devices came into existence.

f) Jacquard's Loom and punch cards :

One of the textile manufacturers called Joseph Marie Jacquard discovered a mechanism for automated weaving of clothes in 1802 AD. It was based on a principle of present and absence of some holes, in which principle punch-card were developed afterwards. So he is called father of punch-card concept.

g) Charles Babbage and his analytical machine :

Charles Babbage was a great mathematician at Cambridge University. He developed tow electromechanical calculators called Difference Engine (1822 AD) and Analytical Engine (1833 AD). The were very big achievements in the history of computers and calculators. Not only those calculators, he invented the working principle of computers. 

h) Lady Augusta Ada Lovelace :

She was a very great follower of Charles Babbage and was first to suggest Babbage to use binary system in his machine. Not only this, she made the first program to used in Babbage's machine. So, she is called 'the first programmer'. To honor her work, a programming language called 'Ada' was made and used in US defense department for a long time.

i) George Boole :

One of the greatest achievements of 19th century was the discovery of mathematical logical called 'Boolean Algebra'. He studied and presented the symbolic logics which are the foundation of modern computers. His logics provided basic idea of presenting the electric circuits with binary input (0 or 1) and its output.

j) Dr. Herman Hollerith :

He was census statistician in US bureau of statistics. He is remembered in the history of computers for the following contributions:

• He invented a machine called Tabulation Machine (TM) in 1886 AD which could process on the punch cards and perform census calculating faster than ever before.
• He was the first person to use punch cards practically.

2. Age of Electromechanical Computers :

a) Mark-I : 

In 1937 prof. Howard Aiken developed an electromechanical computer (which is also called the first computer) called Mark-I. It was also called Automatic Sequence Controlled Calculator (ASCC). It was based on Charles Babbage's principle after 100 years of his death. Although, it was very huge (with dimension 51x8x3 cubic feet), technically very complicated, consumed a lot of electricity, generated a lot of heat, it was the milestone in history of computer. It used 18000 vacuum tube (valves) as main memory device. In 1944 AD, Howard Aiken modified Mark-I and invented Mark-II which used 19000 valves.

 

b) Atanasoff Berry Computer (ABC) :

 It is also called the first electronic digital computer. It was invented by J.V. Atanasoff and Clifford Berry in 1939-1942 AD. It used 18000 valves and other 45 valves for internal logic and capacitor for storage of electrical charges. It used punch cards as secondary storage.

3. Age of Electronic Computer :

a) Electronic Numerical integrator And Calculator (ENIAC) :

ENIAC was the product of the work of two men: John W. Mauchly and J. Presper Eckert. They received funds while working at the Moore School of the University of Pennsylvania. At the time of completion in 1946, ENIAC was the largest single electronic apparatus in the world. It was a large-scale, general purpose digital electronic computer built from 17,468 vacuum tubes.

b) John Von Neumann : 

He was a mathematician and in 1945 Ad he discovered a principle of stored program. So, he is called the 'father of stored program'. Before his principle, programs required for the computers were integrated and written permanently in chips, so modification of program was not possible. but after Neumann, such programs were stored inside computer in some storage media, so modification was easy and flexible.

c) Electronic Delay Storage Automatic Computer (EDSAC) :

It was invented by Maurice Wilkes in 1949. It also used vacuum tubes. Although started after EDVAC, It was completed before EDVAC. So, it became the first stored program computer.

d) Electronic Discreate Variable Automatic Computer (EDVAC) :

It was developed by J.P. Eckert and J. Mauchly in 1952. Although started before, it was completed after EDSAC. The construction of EDVAC was supervised by John Von Neumann. So, some people say it as the first storage program computer. It also used vacuum tubes and some internal storage.

e) Universal Automatic Computer (UNIVAC) :

It was the first computer manufactured for commercial used and general purpose digital computer. Before this, all the computers were used either for defense or census. It was also developed by J.P. Eckert and J. Mauchly in 1961.

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