COMPUTER ORIGIN AND EVOLUTION

The word “computer” is derived from the word compute. Computer literally means a machine which does calculation or computation. But its literal meaning is insufficient to describe the actual meaning of computer. Basically, the computer is a device that stores, processes and retrieves (extracts) information in a very short time. Today, it is used in every sphere of human activity.

History

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About 5000 years ago Greek invented a calculating machine called Abacus. This was regarded as the first digital computer. Later, in 1614; the Logarithm table was invented by John Napier. In 1642, a French scientist, Blade Pascal invented a device for additions. This was improved by Godfrey Libnittis, who was the inventor of the multiplication device in 1673. Both these devices were not foolproof at there performance. Thus later in 1820, another scientist named Mr. Charles Thomas, developed prototype of today’s calculator with improved facilities. In 1822, Charles Babage, a British scientist, who was the professor of mathematics, designed a “difference engine” for the Royal Society, which was meant for addition and multiplication. Since, its performance could not overcome the Charles Babage expectations, he developed a more efficient machine which also had the

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facilities to do addition and multiplication, called “analytical engine”. Charles Babage is considered as the “father of modern computer” for his harsh effort and work which lead to the evolution of computers. By 1920, machines that worked on electricity came into being and it greatly increased the speed and efficiency.

The 1970s could be called as the era of the minicomputer. These were progressively smaller and cheaper machines than the standard mainframe era computers. The standard mainframe of the 1970s shrunk from a room full of cabinets and tape drives to a decorative office machine perhaps 3 to 5 feet long and 3 to 4 feet high.

In 1980, Apple realized the Apple II computer, the first true commercial PC. It was a small desktop machine that runs BASIC. This machine had a major impact on the educational market.

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In 1981, all of this changed. The PC was released by IBM, and Lotus developed 1-2-3 based on the Visi-Calc spreadsheet program. This program became the first of the Killer Applications (killer apps) that industry had to run. The PC became an overnight success.

COMPUTER GENERATIONSBased on the increasing technology of the computers, it can be divided into five generations:

FIRST GENERATION COMPUTER

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Computers of the first generation were based on the vacuum tube technology, as shown in figure (a). In 1822, Charles Babbage, a professor of mathematics at Cambridge University, devised a machine called the “Difference machine” meant to perform simple computations needed for setting up trigonometric and logarithmic tables. Hence, he was known as the “Father of modern day computers”. After the World War II, there was in need of advanced calculator for calculation. By that time, many mechanical desk calculators were introduced. In 1946, the University of Pensylvania introduced the world’s first electronic computer ENIAC (Electronic Numerical Integrator and Calculating Machine). The ENIAC performed 5000 addition per second, consumed 150 kilowatts of power. Although, it had many other limitations as such. It was so huge and generated so much heat that it needed to be water cooled. Its weight was 30

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tonnes (approx.) and there were about 18,000 electronic valves. ENIAC was followed by EDSAC (Electronic Delay Storage Automatic Computer) in 1950 and UNIVAC (Universal Accounting Computer) in 1951.

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Fig (a): Vacuum Tube

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In general, the first computer generation computer faced the following limitations:

1. Low operating speed.2. Restricted computing capacity.3. High power consumption.4. Short life span.5. Large space requirement.6. Generate much heat that needed to be water cooled.

SECOND GENERATION COMPUTERS

In the year 1950-51, the vacuum tubes were replaced by transistors. This decreased the size and increased the efficiency manifold (many & varied). If the computer in first

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generation could perform about 500 tasks per second, then the second generation computers could be able to perform around 5 lakh tasks. The use of computer increased from 1st

generation to 2nd generation.

Fig (b): Transistor

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THIRD GENERATION COMPUTERS

Third generation computers were introduced in the early 60’s. The basic distinguishing characters of the 3rd

generation computers from the other generation computers were the introduction to the IC’s (Integrated circuits). It is an arrangement where micro sized crystals are connected on a surface using tiny metal strings. In IC’s several logical gates are fabricated on a single piece of silicon. Size of the computers was further reduced, computing power increased, cost reduced. In this generation SSI (Small scale integrated) to MSI (Medium scale integrator) then to LSI (Large scale integrator). IC helped in making the computer much & more compact and increased the storage capacity. Using various

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terminals, more than one person was able to work on the same computers simultaneously. IBM360 series and IBM370/168 belonged to the third generation computers.

Fig (c): Integrated Circuit (IC)

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FOURTH GENERATION COMPUTERS

By the end of 1970, 4th generation computers emerged with a lot of revolutionary innovations. VLSI technology of IC’s made it possible to make complete circuit of ALU (Arithmetic and Logic Unit) and CU (Control unit) within a single chip which comprise of the main part of computer called CPU (Central Processing Unit). Silicon chips were introduced as microprocessors in the fourth generation computers. Circuit space got reduced as a result & it could finally be kept on a table top. Compared to the other generation computers, the size and prize were brought down remarkably in the fourth generation. This increased the popularity and

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accessibility of computers among the general public. It came to be increasingly employed for accessing knowledge and entertainment. Apple series one & two, Intel 4004 etc, belong to this generation.

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Fig (d): Basic Block Diagram of a Computer System

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FIFTH GENERATION COMPUTERS

The computers being developed presently belong to the fifth generation. The most significant aspect of this generation of computers is expected to be the “artificial intelligence”. The chips used in these computers are “Very Large Scale Integrated” circuit (VLSI) with high power & efficiency. Besides VLSI there is LSI, ULSI types of chips which are also being used in fifth generation computers.

Japanese and Americans are working on it. The fifth generation computers might well have the ability to recognize voice, read written matter and possibly, think on its own.

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