The dictionary meaning of the 'Software' is the instructions which control what a computer does. The software enables the hardware to operate. Without software,a computer cannot do anything and become only a deal machine. Software is necessary for a computer system to work at the optimum level. Software consists of series instructions and decision rule that instruct the computer in executing a given task. Software is also called a computer program. It is written by using a programming language which the computer can understand. Soft can be divided into two major categories. 1)System Software 2)Application Software System software The system software which is designed to operae, control and manage the actual operation of the computer hardware is called system software. Being an artificial machine, a computer does not know how to do even a small task.