Concept of System
It is stated that systems do exist if people perceive them. But, what constitutes a system? As an answer to this question let us try to understand the concept. It may bestated that "a system is a group of things or parts working together." In other words,system is a set of entities: man, machine and materials integrated and bound by a functional relationship: They are so integrated that a change in the functioning of onentity affects the effectiveness of others, and thereby the overall functioning of the set as a whole. Thus, in short, a system is an organisation that can be reduced or divided to its component' parts on the basis of their functions. Each functional part constitutes a subsystem which can be further reduced to its own component parts. The division is undertaken with a definite purpose in view, and is not attempted arbitrarily for the sake of division. Every system undergoes certain phases of development which are known as system life cycle. It involves analysis, design, implementation, operating evolution, decay and replacement. The enclosed diagram indicates clearly some of these aspects.