Computersight -

A computer is a machine that executes programs. A program is a set of instructions written in any computer language. Computer processes data to produce information. Modern computers are digital in nature, i.e., all the data and information is expressed in terms of numbers. These numbers are represented using two states:-

On/ off

It is- High voltage/low voltage.

Computer can be classified according to their size and speed as follows.

Microcomputers

Microcomputer is single user computer with their CPU on a single chip called the microprocessor. These are further divided into:-

a)      Personal computer: these are specially designed for the use by one person at a time. They have their own central processing unit, memory operating system and peripherals.

b)      Workstations: these are high performance computer with excellent graphics and fast processors, often a part a network. They are used for CAD/ CAM, DTP and other scientific applications.

c)      Minicomputers: minicomputers are multi-user computers, suitable for use in small companies, government organizations and universities. The keyboards and the monitors are remote from the main processor, connected by links in minicomputer. VAX is a very popular minicomputer.

d)      Mainframes: mainframes are large and fast multi-user computer systems, designed to manage very large amount of data and information. Mainframes are normally used in large corporations, universities and military installations etc.

e)      Supercomputers: supercomputers are the most powerful category of computers. These are very expensive and are used for weather forecasting, complex 3-D modeling etc. Cray T3E-900 GRAPE-4 is two powerful supercomputers.

*Characteristics of Computers

Image via Wikipedia

·        Speed: a computer can executed million of instructions in a second. A computer having high speed is always more efficient. It is the microprocessor that determines the speed of a computer.

·        Storage: computers have their own memory units. A memory unit can store large amount of data and information. Data can be retrieved with in seconds from the memory of the computer. Hard disk, floppy disk CD, DVD etc are few storage devices.

·        Accuracy: computer system is very efficient. It always gives accurate results. Errors occur due to human inefficiency. For example, feeding incorrect data, errors made in program writing etc.

·        Versatile: a computer can perform various activities, from simple calculations to complex 3-D modeling of rockets and missiles etc. computers can even communicate with each other. This has led to the development of computer net workers. Internet is one such global net work.

·        Diligence: a computer does not suffer from human weaknesses, such as, tiredness, boredom, lack of concentration etc. therefore; it can work day and night for hours and hours, provided it has power backup.

·        Automatic: computer is automatic machines. Once they receive the instructions; they perform the whole task flawlessly, provided that the program is error-free.