A computer is a machine that takes some input data and performs a series of calculations and then computes the intended result. A computer automatically performs the instructions given to it in the form of a computer program.
The computer which is programmable had taken a shape in 19th century through the mechanical computer by Charles Babbage. In 20th century electronic computers were initially designed using big electrical components. After the invention of semiconductors and electronic transistor devices, the size of the computer drastically reduced. After microprocessors are invented, the era of personal computers has started.
A computer understands and performs arithmetic and logical calculations in terms of two binary arithmetic system, namely, 0 and 1. A device that stores and changes its state from 0 to 1 or vice-versa is called a switch. This is the fundamental building block of an electronic device including a computer.
A computer has devices of three types, namely, input devices, the processor and the output devices. The input devices (keyboard, mouse) allow the inputting data to the software program. The processor (CPU : central processing unit) performs instructions by reading from main memory and storing results into the main memory. The output devices (monitor, printer) allow access to the processed output.
A computer is now used in every field for automatically furnishing services by application softwares. A computer is used for data storage too. A computer has the advantages that it can work 24/7, performs complex operations and eliminates human errors. It can performs work very quickly in a reusable manner. It eliminates requirement of a lot of stationary and manual records. In this age of information technology and telecom era, computers are a great boon of the inventors to the human kind.