Category : 8th Class
Introduction to Data Representation
Introduction
Classification of computers are basically divided according to their speed, memory capability, peripheral support etc. Different types of computers are used in different sectors. Microcomputer is the personal computer, whereas mini and super computers are more advanced and used in the sectors where big amount of data is processed. Number system in computing are used for coding characters in numbers. There are four type of number systems in digital system. They are Binary, Octal, Decimal and Hexadecimal. This chapter includes the classification of computer's number system.
Binary Number System
A number system with a base2 is known as binary number system. The whole binary number system depends on two digits, these are 0 and 1 respectively. By using these two digits, the numbers in binary number system are written. Thus the place value of a digit in a number increases in the power of 2 from right to left.
Characteristics
The following example shows how to convert binary number 1010101 into decimal number:
Power of 
6 
5 
4 
3 
2 
1 
0 
Binary number 
1 
0 
1 
0 
1 
0 
1 
Example
Decimal Number System
A system with base = 10 is a decimal number system. Thus, it means that there are ten basic digits on which the decimal number system depends. The digits are 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9. By using these ten digits, all the numbers in decimal number system are .written. Thus, the place value of a digit in a number increases the power from right to left.
Characteristics
The following are the place value of each digit of number 5471:
Example:
Decimal Binary Conversion Table
Decimal 
Binary 
0 
0000 
1 
0001 
2 
0010 
3 
0011 
4 
0100 
5 
0101 
6 
0110 
7 
0111 
8 
1000 
9 
1001 
10 
1010 
11 
1011 
12 
1100 
13 
1101 
14 
1110 
15 
1111 
Steps to convert Decimal to Binary conversion by short division by two with remainder:
Example:
2 
256 
0 
2 
128 
0 
2 
64 
0 
2 
32 
0 
2 
16 
0 
2 
8 
0 
2 
4 
0 
2 
2 
0 

1 

Octal Number System
Octal number system consists of eight digits from 0 to 7 the base of Octal system is 8. Each digit position in this system represents the power of 8. Any digit in this system is always less than 8.
Characteristics
Example:
Hexadecimal Number System
The Hexadecimal number system is based on base 16. Therefore, it means, there are 16 basics digits on which whole hexadecimal number system depends. These digits are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 and 15, whereas the numbers 10, 11, 12, 13, 14, and 15 are also represented as A, B, C, D, E and F. By using these 16 digits all the numbers in Hexadecimal number system are written. Thus the place value in hexadecimal system is increased in the power of 16 from right to left.
Characteristics
Example
Introduction to ASCII
ASCII (American Standard Code for Information Interchange) is a seven bit code which includes 128 characters. Basically it is a method of character encoding. In 128 characters. Basically it is a method of character encoding. In 128 characters, 33 are printable characters and 95 are nonprintable characters. The ASCII code assigns an integer value for each symbol in the character set, such as letters, digits, punctuation marks, special characters and control characters.
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