Computer

Definition of a computer:

A computer is an electronic device capable of executing instructions, developed based on algorithms stored in it memory, to process data fed to it and produced the required results faster than human beings.

Main concepts:

In order to solve a problem using a computer, it is necessary to find and write an algorithm for it. An algorithm  is a finite sequence of instructions. Each instruction should be precise, unambiguous, and capable of being carried out by a machine in a finite time.

An algorithm can be expressed in a graphical form known as a flowchart.  A programming language is a precise notation used to express algorithms. An algorithm expressed in a programming language is called a  computer program. The program written by a programmer is called the “source program”. The translated program in machine code is called “ object program”.

Parts of a computer:

Basically a  computer has three main  parts. They are given below.

• Input unit
• CPU
• Output unit

1. Input unit:

 Input unit is used to feed the data and instructions into the computer. The        input unit consists some input devices.  Keyboard, mouse, joystick, scanner are some examples for input devices.

2.CPU:

CPU means Central Processing Unit.  This part executes the instructions in the

Program one by one. It has three major parts. They are,

• MU
• ALU
• CU

MU:

It means Memory Unit. It is used to store the programs and data.

ALU:

It means Arithmetic and Logic Unit. All the arithmetic and logical operations are      

Being carried out in this unit.

CU:

It controls and directs various units of a computer.

3.Output unit:

It is used to display the results. This unit has some output devices. Monitor,   

Printer are output devices.

Human being – computer :

A computer can be compared to a human being. A human being reads data using eyes, hears the data using ears, gathers some data using feelings, tastes some data  using tongue and smell some data, using nose. So the parts like eye, ear, nose are used to get input and hence these parts are comparable  to the input units (or) input devices of a computer. The output of information can be given orally using mouth and in writing using hands and sometimes using actions, facial expressions and body postures. These parts such as mouth, hands etc., are used for giving out the information and are comparable to the output devices of a computer. The logical and arithmetic operations are done using the brain. The data are also kept in the memory .  So, the brain is considered as the memory as well as the processing unit.