COMPUTER HISTORY

EVOLUTION OF COMPUTERS

Ancient people used stones for counting or made scratches on wall or tied knots in a rope to record information. But all these were manual computing techniques. Attempts had been going on for developing faster computing devices and the first achievement was abacus, the pioneer computing device used by man.

ABACUS

Around 3000 B.C, the Mesopotamians quite unknowingly laid the foundation of  computer era.

They discovered an earliest form of a bead-and-wire counting machine, which subsequently came to be known as abacus. The Chinese improved upon the abacus so that they could calculate and count faster

NAPIER’S ‘LOGS’ AND ‘BONES

John napier (1550-1617) developed the idea of logarithm. He used logs to transform multiplication problem to addition problem. Napier’s logs and bones later became basis for a well known invention known –the computing machine known as “slide rule” (invented in 1662). Napier also advised a set of numbering rods known as Napier's bones. He could perform both multiplication and division with these ‘bones’.

PASCAL’S ADDING MACHINE

The idea of logarithm, developed in 1614, notably reduced the tedium of repetitive calculations.

Blasé Pascal, a French mathematician, invented a machine in 1642 made up of gears which was used for adding numbers quickly. This machine was known as adding machine (also known as Pascaline) and was capable of addition and subtraction.

PASCALINE

It worked on clock work mechanism principle. The adding machine consisted of numbered toothed wheels having unique position values. The rotation of wheels controlled the addition and subtraction operations. The machine was capable of carry-transfer automatically.

LEIBNITZ’S CALCULATOR

Gottfried Leibnitz, a german mathematician, improved an adding machine and constructed a new machine in 1617 that was capable to perform multiplication and division as well. This machine performed multiplication through repeated addition of numbers. Leibnitz’s machine used stepped cylinder each with nine teeth of varying lengths instead of wheels as was used by Pascal.

JACQUARD’S LOOM

Joseph jacquard manufactured punched cards at the end of American revolution and used them to control looms in 1801. Thus the entire control of weaving process was automatic. The entire operation was under control of a program . with the historic invention of punched cards, the era of  storing and retrieving information started that greatly influenced the later inventions and advancements.

BABBAGE’S DIFFERENCE ENGINE

Charles Babbage, a professor of mathematics, developed a machine called DIFFERENCE ENGINE in the year 1822.this machine was expected to calculate logarithmic table to a high degree of precision. The difference engine was to calculate various mathematical functions. The machine was capable of polynomial valuation by finite difference and it’s operation was automatic Multi-stop operation.

BABBAGE’S ANALYTICAL ENGINE

In 1833, Charles Babbage started designing an analytical engine which was to become real ancestor of modern day computer. With the methodical design of his analytical engine, Babbage meticulously established the basic principles on which today’s computers work.

The first innovation enabled the machine to compare quantities and then decide which of the instruction sequences to follow. The second permitted the results of a calculation to change numbers and instructions already stored in the machine.

His great inventions of difference engine and analytical engine earned Charles Babbage the title “FATHER OF MODERN COMPUTERS”.

MARK-1

Prof. Howard  Aiken (1900-1973) in USA constructed in 1943 an electromechanical computer called mark-1 which could multiply two ten digit numbers in 5 seconds- a record back then.MARK-1 was the first computer which could perform automatically without any manual intervention according to preprogrammed codes.    

   COMPUTER GENERATION
Generation in computer terminology is a change in technology a computer is/was being used. Initially, the generation term was used to distinguish between varying hardware technologies. But nowadays, generation includes both hardware and software, which together make up an entire computer system. There are totally five computer generations known till date. Each generation has been discussed in detail along with their time period and characteristics. Here approximate dates against each generations have been mentioned which are normally accepted. Following are the main five generations of computers1. First GenerationThe period of first generation: 1946-1959. Vacuum tube based.

2. Second GenerationThe period of second generation: 1959-1965. Transistor based.

3. Third GenerationThe period of third generation: 1965-1971. Integrated Circuit based.

4. Fourth GenerationThe period of fourth generation: 1971-1980. VLSI microprocessor based.

5. Fifth GenerationThe period of fifth generation: 1980-onward. ULSI microprocessor based







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