Introducation to computers

Computer systems

A Computer is an electronic device which performs operations such as accepts data as an input, store the data, manipulate or process the data and produce the result as an output.

Main task performed by a computer

• Accept the data
• Process or manipulate the data
• Display or store the result in the form of human understanding
• Store the data, instructions and results.

Characteristics of Computers

Speed

You will be surprised to know that computer can perform millions (1,000,000) of instructions and even more per second. Therefore, we determine the speed of computer in terms of microsecond (10-6 part of a second) or nano-second (10-9 part of a second). From this you can imagine how fast your computer performs work.

Accuracy

Suppose someone calculates faster but commits a lot of errors in computing. Such result is useless. There is another aspect. Suppose you want to divide 15 by 7. You may work out up to 2 decimal places and say the dividend is 2.14. I may calculate up to 4 decimal places and say that the result is 2.1428. Someone else may go up to 9 decimal places and say the result is 2.142857143. Hence, in addition to speed, the computer should have accuracy or correctness in computing. The degree ofaccuracy of computer is very high and every calculation is performed with the same accuracy. The accuracy level is determined on the basis of design of computer. Theerrors in computer are due to human and inaccurate data.

Diligence

A computer is free from tiredness, lack of concentration, fatigue, etc. It can work for hours without creating any error. If millions of calculations are to be performed, a computer will perform every calculation with the same accuracy. Due to thiscapability it overpowers human being in routine type of work.

Versatility

It means the capacity to perform completely different type of work. You may use your computer to prepare payroll slips. Next moment you may use it for inventory management or to prepare electric bills.