Data Representations

Data Representations

Computer handles data in the form of ‘0’(Zero) and ‘1’ (One). Any kind of data like number, alphabet, special character should be converted to ‘0’ or ‘1’ which can be understood by the Computer. ‘0’ and ‘1’ that the Computer can understand is called Machine language. ‘0’ or ‘1’ are called ‘Binary Digits’(BIT). Therefore, the study of data representation in the computer is important.

·        A bit is the short form of Binary digit which can be ‘0’ or ‘1’. It is the basic unit of data in computers.

·        A nibble is a collection of 4 bits (Binary digits).

·        A collection of 8 bits is called Byte. A byte is considered as the basic unit of measuring the memory size in the computer.

·        Word length refers to the number of bits processed by a Computer’s CPU. For example, a word length can have 8 bits, 16 bits, 32 bits and 64 bits (Present day Computers use 32 bits or 64 bits)

Computer memory (Main Memory and Secondary Storage)is normally represented in terms of KiloByte (KB) or MegaByte (MB). In decimal system, 1 Kilo represents 1000, that is , 10³. In binary system, 1 KiloByte represents 1024 bytes that is 2¹⁰. The following table represents the various memory sizes:

Bytes are used to represent characters in a text. Different types of coding schemes are used to represent the character set and numbers. The most commonly used coding scheme is the American Standard Code for Information Interchange (ASCII). Each binary value between 0 and 127 is used to represent a specific character. The ASCII value for (blank space) is 32 and the ASCII value of numeric 0 is 48. The range of ASCII values for lower case alphabets is from 97 to 122 and the range of ASCII values for the upper case alphabets is 65 to 90.

The speed of a computer depends on the number of bits it can process at once.

For example, a 64- bit computer can process 64-bit numbers in one operation, while a 32-bit computer break 64-bit numbers down into smaller pieces, making it slower