What is a Computer?

A computer is an electronic device that stores, retrieves and performs mathematical calculations and logical operations through the execution of a sequence of programmed instructions. Today's computers have the ability to process very large amounts of data within a short time.

Computers have some advantages over the usual type writers. They can perform millions of instructions per second which increases human interactivity with the machine.Their ability to store large quantities of data makes them unique devices to work with. These days there are large capacity computers which can store and process a good amount of data at high speed without any problem.

Computers are clasified according to their physical size and input. Those classified according to their physical size are:

• Mainframe. These computers have large peripherals, backing storage and faster Central processing Unit. Usually, operation of Mainframe computers involves large number of staff.
• Miniframe. These computers have slower processing power and smaller physical size as compared to Mainframes.
• Microcomputers. They are mainly used in data acquisition. They include desktops, laptops/notebooks etc. Their processing power is based on Microproccessor.

Computers classified according to their input include:

• Analogue. In Analogue computers processing of data is done through a representation of a continuous wave signal. Application of such computers include weather forecasting.
• Digital computers process their data through a represeantation of binaries. The digits (1's or 0's) which represent data in digital form are called bits. Main application is in business.
• Hybrid computers combine the processes of the two above (Analogue and Digital) and are used in specialized applications which include control of space ships.