Introduction to Computer (Hardware and Software)


The term computer is derived from word ‘compute’ which means to calculate.

Computer is basically a group of electronic devices that can accept data, conduct a series of arithmetic and logical operations on it and give result of these operations as information that is useful to people.

It is a machine that performs pre-defined or programmed computations or control operations that are expressible in numerical and logical form at a high speed and with great accuracy.

In other words, Computer is an electronic device capable of performing commands and these commands are basically input, output, storage, arithmetic and logical operations.

A computer is a programmable electronic device that accepts raw data and instruction from input device, process data and provides output as information in output device.

All the modern computers are digital and represents information in binary digits. They represent data using two distinct values.

In binary system we have only two digits (bits) – 0 and 1 to represent data. Since the bit is a very small unit, virtually, it cannot convey much information while used single.

Combination of eight bits is called a byte. A byte is the fundamental unit of data representation in computer. A byte can represent one character of data. Modern computers are capable of processing more than one byte at a time.

Computer System

A computer system consists of two major components, namely, hardware and software.

All physical components that forms computer system are known as computer hardware.

Software is basically collection of different programs that tells computer’s hardware what to do.

Computer System
Figure: Computer System


All physical components that make up a computer is known as computer hardware.

It includes all components that we can see and touch i.e. processor, input devices like keyboard, mouse, output devices like visual display unit (VDU), printer, speaker, connecting wires, casing, storage devices etc. Block diagram depicting major components of computer is shown below:

Computer Block Diagram
Figure: Computer Block Diagram

Computer hardware consists of different functional units: input unit, central processing unit (CPU) which consists arithmetic logic unit (ALU) and control unit (CU), memory unit and output unit.

Computer accepts digital data from user with the help of input devices like mouse, keyboard, microphone etc. Received data from user is either stored in the memory for later use or immediately processed by the arithmetic and logic unit to carry out the desired operations. After processing, processed output known as information is either stored in memory for later use or sent to user with the help of output devices like monitor, printer, speaker etc. All the above mentioned activities are controlled and coordinated by the control unit.


Set of instructions that tells the computer hardware what to do is known as computer program. This program or collection of such programs is known as computer software. Concept of software is illustrated in following figure:

Illustration of Software
Figure: Illustration of Software

Software guides and tells computer hardware how to accomplish a task. Computer software can be categorized into two broad categories as system software and application software which we will be discussing in the next articles.