Computers – An Introduction
A computer is defined as an electronic device that accepts input, processes it as per the given instructions and produces meaningful output. The term computer is used to describe a device which is combination of electronic and electromechanical devices. It is derived from the word “Compute” which means Calculation. “Charles Babbage” is known as the father of the computer.
Data and Information
Data refers to raw facts that are gathered and fed to the computer. A computer a store retrieves synthesizes data to produce information. A computer organizes data from many sources an turns it into information which can be applied in making decisions and solving problems.
History of Computers
Early civilizations used stones and sticks for calculation. However, as trade and commerce evolved and calculations grew in complexity, human beings felt the need for fast and accurate calculation devices.
Abacus – 500 BC
It is widely believed that China developed the abacus around 500 BC. A rectangular wooden frame with a mid-bar, the Chinese abacus had horizontal wires and specific beads fixed across the mid-bar. The abacus was used for addition and subtraction. The Japanese and Russians soon made their own versions of the abacus.
In 1617, a Scottish mathematician, Sir John Napier, invented the Napier Bones – set of 11 rectangular rods made out of carved bones. This device was used for multiplication and division, besides addition and subtraction.
The first mechanical calculator was invented in 1642 by a French mathematician and philosopher called Blaise Pascal. This device was called Pascal’s Calculator and was used for addition and subtraction only.
A German mathematician, Gottfried Leibniz, modified the Pascal’s Calculator in 1671. His device could add, subtract, multiply and divide numbers.
Analytical and Differential Engine
In 19th Century, Charles Babbage, professor in Cambridge University, invented the first mechanical computer. He invented the analytical engine and differential engine. In 1930, Howard Aiken designed and built a computer with electrical function. However, this machine was bulky. It acquired a proper design in 1948 and was named Mark=1. It remained in use till 1959.
Electronic computers first appeared in 1946. They were gradually upgraded.
Generations of Computers
The first electronic component used in the electronic computer was the diode valve. Other components such as the transistor. IC (integrated Circuit) and microprocessor followed. Computers can be classified into four generations based on the basic components which comprise.
First Generations (1951 -1958)
The first electronic computer was built in Pennsylvania University, USA in 1946. It was called ENIAC. First Generation computers are characterized by
o Huge size, heavy weight and high cost
o The electronic valves used as the main components produced a lot of heat and consumed a lot of power
Second Generation (1959 – 64)
The second generation computers which appeared in 1959 had silicon transistors instead of electronic valves. The main characteristics of the second generation computers were o Reduction in size and weight
o Reduction in cost
o They were portable
o The heat dissipation was negligible
o There was a marked improvement in terms of the reliability and accuracy of the information that they produced
Third Generation (1965- 70)
In 1964, the Integrated Circuit (IC) replaced the transistors and a new generation of computers evolved with improved features. The third generation computer
Fourth Generation (1971- 1985)
Till the fourth generation computers were built, a number of silicon chips were used in discrete circuit. Henceforth, a single microprocessor chip was used to accommodate the entire functional circuit. The Main characteristics of fourth generation computers...
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