INTRODUCTION

‘Computer’ as the name suggests is meant for computation. So knowledge of computer is not possible without the knowledge of various number systems, number formats and their advantages and drawbacks. That is why mathematicians always played a major role in the advancement of computer science.

From pre-historic age when human beings were formed by evolution, numbers are being used to count, label and measure. Initially tally marks were used for counting. Bones, cave pictures from pre-historic age have been discovered with marks cut into them that are similar to tally marks. It is assumed that these tally marks were used for counting elapsed time, such as numbers of days or to keep count of animals. Tally mark was not a positional number system. From tally mark evolved the Roman number system. All these systems have limitations of representing large numbers. Historically it is said that number system with place value was first used in Mesopotamia, from 3400 BC onwards. In India, Aryans used the word SHUNYA in Sanskrit to represent void. This is used as ZERO in mathematics. Greeks were confused about using zero. But eventually this place holder developed today's mostly used positional number system where the value of the number depends on the position of the digits. For example 349= 3*102 + 4*101 + 9*100 as 9 is at position 0, 4 is at position 1 and 3 is at position 2. And obviously the number 1000000 is larger than the number 999999. In fact the value of a number in a positional number system depends on two things, one position and the other is base of that number system.