1.2 ORIGIN OF COMPUTERS
Origin of computer could be rigorous efforts of men to count large numbers. This process
of counting of large numbers generated various systems of numeration like Babylonian
system of numeration, Greek system of numeration, Roman system of numeration and
Indian system of numeration. Out of these the Indian system of numeration has been
accepted universally. It is the basis of modern decimal system of numeration 0-9.
1.2.1 Abacus
Nearly 5,000 years ago, the “abacus” was developed in China in 3000 B.C. The word
abacus means calculating board. The “abacus” may be considered the first computer and
it has been used since ancient times by a number of civilizations for basic arithmetical
calculations. A modern form of abacus is given in Figure 1.1.
The abacus is also called a counting frame, which is a calculating tool for performing
arithmetic operations. The Chinese abacus has a frame holding vertical wires, with seven
beads on each wire. A horizontal divider separates the top two beads from the bottom
five, sometimes referred to as the heaven and the earth beads. The arithmetic calculations
are performed by manipulating the beads by using the principle of positional weight of
beads on a rack. Abacus is used even today to teach small children how to count. A
skilled abacus operation can be as fast as a hand held calculator.
1.2.2 Napier’s Bones
John Napier was a mathematician who became famous for his invention of logarithms.
The used of "logs" enabled him to reduce any multiplication problem. John Napier built a
mechanical device for the purpose of multiplication in 1617 A.D. The device was known
as Napier‟s bones. His "bones" are set of eleven rods side by side products and quotients
of large numbers can be obtained. The sticks were called "bones" because they were
made of bone of ivory.
1.2.3 Slide Rule
English mathematician E. Gunter developed the slide rule. This machine could perform
operations like addition, subtraction, multiplication, and division. Although the slide rule
appeared in various forms during the seventeenth century, it consists of two movable
rulers placed side by side. Each ruler is marked off in such a way that the actual distances
from the beginning of the ruler are proportional to the logarithms of the numbers printed
on the ruler. By sliding the rulers, one can quickly multiply and divide
1.2.4 Pascal's Calculator
Blaise Pascal was a French mathematician and one of the first modern scientists to
developed and build calculator. He developed a machine at the age of 19 that was capable
of adding and subtracting numbers. The machine was operated by dialing a series of
wheels, gears and cylinders.
1.2.5 Leibniz’s Multiplication and Dividing Machine
Like Pascal, Gottfried Leibniz was a seventeenth century scientist who recognized the
value of building machines and built around 1673 a mechanical device that could do
mathematical calculations and save labor too.
1.2.6 Difference Engine
Babbage outlined the basic elements of a modern general purpose computer which was
based on the method of finite differences. It uses only arithmetical addition and removes
the need for multiplication and division which are more difficult to implement
mechanically. Charles Babbage is called the father of the computer.
1.2.7 The Analytical Engine
The Analytical Engine marks the progression from the arithmetic calculation to generalpurpose computation. It was also developed by Charles Babbage. This machine was
based on the principle that, for certain formulas, the difference between certain values is
constant. The Analytical Engine has many essential features found in the modern digital
computer.
The Engine had a 'Store' (memory) where numbers and intermediate results could be
held, and a separate 'Mill' (processor) where the arithmetic processing was performed. It
had an internal stock of the four arithmetical functions and could perform direct
multiplication and division. It was also capable of functions like: conditional branching,
looping (iteration), microprogramming, parallel processing, latching, and polling etc. The
logical structure of the Analytical Engine was essentially the same as that which has
dominated computer design in the electronic era.
1.2.8 Mechanical and Electrical Calculator
In the beginning of 19th century, the mechanical calculator was developed to perform all
sorts of mathematical calculations. Up to the 1960s, it was widely used. Later the rotating
part of mechanical calculator was replaced by electric motor. So it was called the
electrical calculator.
1.2.9 Modern Electronic Calculator
The electronic calculator used in 1960s was run with electron tubes, which was quite
bulky. Later it was replaced with transistors and as a result the size of calculators became fairly small. The modern electronic calculator can compute all kinds of mathematical
computations and mathematical functions. It can also be used to store some data
permanently. Some calculators have in-built programs to perform some complicated
calculations. Modern electronic calculators contain a keyboard with buttons for digits and
arithmetical operations. These calculators can perform sophisticated arithmetic and
financial computations such as converting from polar to rectangular coordinates, taking
square roots, computing logarithms and trigonometric relationships.
