### Introduction

• The main function of a computer is to process the input data according to a specific program to produce the desired output.This is the reason why a computer is often viewed as a data processing device.
• Various components of a computer work coherently to perform different operations to process the data according to program instructions.
• Now-a-days computers have something to offer to everyone. Whether it is an engineer, a business tycoon, a graphic designer, an accountant, a statistician, a student or even a farmer; everyone is now making use of computers.
• A computer system consists of two parts – hardware and software.

### Definition

• Computer is an electronic device that performs mathematical/logical as well as non-mathematical/non-logical operations in order to achieve the results.

### Features

• Computer takes the raw data as input and performs several operations on these data in the form of processing in order to produce/achieve the desired output.
• Computer is an electronic device which performs three basic tasks/operations i.e., inputting, processing and outputting. A computer accepts the input through various input devices such as mouse, keyboard etc. After receiving the input data, computer performs different operations required by the user on these input. Finally, computer generates the resultant of the processed data as the output through various output devices such as monitor, printer etc. Hence, a computer is a data processing device.

### Characteristics

The following characteristics of the computers that have made them so powerful and universally accepted machine in the world these days –

• SPEED :
• In general, no human being can compete to solving the complex computation, faster than computer.
• Computers work at an incredible speed.It takes only few seconds for calculations that we take hours to complete.
• A powerful computer is capable of performing about 3-4 million simple instructions per second.
• The processing speed of computer is measured in the range of microsecond (10^6 part of a second) or nanosecond (10^9  part of a second). From this, we can imagine how fast our computer performs work.
• ACCURACY/EFFICIENCY :
• In addition to being fast, computers are also accurate. Since computer is programmed, so what ever input we give it gives result with accuracy.
• The degree of accuracy of computer is very high and every calculation is performed with the same accuracy.
• Errors that may occur can almost always be attributed to human error (inaccurate data, poorly designed system or faulty instructions/programs written by the programmer).They do not create errors itself.
• STORAGE CAPACITY:
• Computer can store mass storage of data in appropriate formats in their in-built memory.
• Today’s computers can store large volumes of data. A piece of information once recorded (or stored) in the computer’s permanent memory, can never be forgotten/lost in normal condition and can be retrieved almost instantaneously.
• Computer stored data can be also taken outside from computer easily and can be carried to other computers.
• DILIGENCE/CONSISTENCY :
• Computer can work for hours without any break and creating errors because a  computer is free from tiredness, lack of concentration, fatigue, etc.
• Unlike human beings, computers are highly consistent. They do not suffer from human traits of boredom and tiredness resulting in lack of concentration. computers, therefore, are better than human beings in performing voluminous and repetitive jobs.
• If millions of calculations are to be performed, a computer will perform every calculation with the same accuracy.
• Due to this capability it overpowers human being in routine type of work.
• Computer is a considered as a consistent machine, i.e. computer never gets tired of working more. We can use computer to perform our task without any error for any number of hours/days/weeks/months continuously without stopping it with similar processing speed as found in most of the huge servers.
• AUTOMATIC –
• Computer does its all processing work automatically  once all of its instructions are accepted i.e. once started on job they carry on until the job is finished without any further human assistance.
• VERSATILITY :
• We can use same computer to perform completely different type of works when we need. We can’t change computer for other works normally.
• This most wonderful feature of computers allow the activities of different types of jobs from simple calculation to the complex scientific operations and computations and is also capable of preparing the examination marks sheets, bills, letters, documents and many more.
• Computers are versatile machines and are capable of performing any task of different sectors such as works of Railway/Air reservation, Banks, Hotels, Weather forecasting and many more.
• RELIABILITY –
• Reliability is a very big characteristic of computer.
• Today, an e-commerce companies, organizations, factories, hospitals, agencies, banks, railways and many more, faithfully rely on the computer’s work.