Computer is the most powerful tool the man has ever created. Computers have made a great impact on our everyday life. Their presence is felt at almost every working place, homes, schools, colleges, offices, industries, hospital, banks, retail stores, railways, research and design organizations and so on. Computer, large and small, are used nowadays by all kinds of people for a variety of tasks in a modern and industrialized society.

A computer is basically a programmable computing machine. Earlier, computers were used for complex computation and used by only scientists and engineers. The trend was to design large and powerful computer to handle large data and solve complex problems. They were very costly and hence, only large organizations could afford them. The technological breakthrough in design and fabrication of semiconductor devices has made now possible to manufacture powerful microcomputer which are within the reach of small organizations and even individuals. These computers beings very fast can be used not only for computation but also to store and retrieve information, to control certain process and machine, to measure and display certain physical and electrical quantities and so forth. Development in software allow massive application of computer for non-computational jobs like text preparation, manipulation, storage and retrieval; transmission of texts, graphics and pictures from one place to another; and artificial intelligence and expert systems, for example, robots and so on.

Shortly, we can say that—

Computer is an electronic device which is capable of doing airthmatical calculation and taking logical decision and giving very accurate result. It can also store large volume of data for long time.That called computer.