Evolution Of Computers

The growth of computer industry started with the need for performing fast calculations.
The manual method of computing was slow and prone to errors. So attempts were
made to develop faster calculating devices. The journey that started from the first
calculating device i.e. Abacus has led us today to extremely high speed calculating
devices. Let us first have a look at some early calculating devices and then we will
explore various generations of computer

ABACUS

Abacus was discovered by the Mesopotamians in around 3000 BC. An abacus consisted
of beads on movable rods divided into two parts. (Fig-1) Addition and multiplication of
numbers was done by using the place value of digits of the numbers and position of

beads in an abacus..

The Chinese further improved on the abacus so that calculations could be done more
easily. Even today abacus is considered as an apt tool for young children to do
calculations. In an abacus, each row is thought of as a ten’s place. From right to left ,
row no-1 represents the one’s column and the second column represents ten’s place.
The third column represents the hundred’s place and so on. The starting position of the
top beads (representing the value of five) is always towards the top wall of the abacus
while the lower beads (representing the value of one) will always be pushed towards
the lower wall as a starting position.



NAPIER’S  LOGS AND BONES


The idea of logarithm was developed by John Napier in 1617. He devised a set of
numbering rods known as Napier’s Bones through which both multiplication and
division could be performed. These were numbered rods which could perform
multiplication of any number by a number in the range of 2-9. There are 10 bones
corresponding to the digits 0-9 and there is also a special eleventh bone that is used to
represent the multiplier. By placing bones corresponding to the multiplier on the left side and the bone corresponding to the digits of the multiplicand on the right, the product of two numbers can be easily obtained.

PASCALINE

Blaise Pascal, a French mathematician invented an adding machine in 1642 that was
made up of gears and was used for adding numbers quickly. This machine was also
called Pascaline and was capable of addition and subtraction along with carry-transfer

capability. It worked on clock work mechanism principle. It consisted of various numbered toothed wheels having unique position values. The addition and subtraction operations was performed by
controlled rotation of these wheels.

LEIBNITZ'S CALCULATOR


In 1673 Gottfried Leibnitz, a German mathematician extended the capabilities of the
adding machine invented by Pascal to perform multiplication and division as well. The
multiplication was done through repeated addition of numbers using a stepped

cylinder each with nine teeth of varying lengths.

JACQUARD'S LOOM

In order to make the cotton weaving process automatic, Joseph Jaquard devised punch
cards and used them to control looms in 1801. The entire operation was under a
program’s control. Through this historic invention, the concept of storing and retrieving

information started.


DIFFERENCE ENGINE AND ANALYTICAL ENGINE

Charles Babbage, an English mathematician developed a machine called Difference
Engine in 1822 which could calculate various mathematical functions, do polynomial

evaluation by finite difference and theoretically could also solve differential equations.

Thereafter in 1833, he designed the Analytical Engine which later on proved to be the
basis of modern computer. This machine could perform all the four arithmetic
operations as well as comparison. It included the concept of central processor, memory
storage and input-output devices. Even the stored information could be modified.
Although the analytical engine was never built that time but Babbage established the
basic principles on which today’s modern computers work.
Both these great inventions earned him the title of ‘Father of Modern Computers’.


MARK 1

In 1944 Prof Howard Aiken in collaboration with IBM constructed an electromechanical
computer named Mark 1 which could multiply two 10 digit numbers in 5 seconds. This
machine was based on the concept of Babbage’s Analytical engine and was the first
operational general purpose computer which could execute preprogrammed

instructions automatically without any human intervention.

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