Function of a Computer

Functioning of a computer is similar to the life of a human. For example, let us understand with the following illustration.
• Consider that your mathematics teacher has given you home work to perform addition of two numbers, and to submit it on the next day.
• The diagram below performs three actions:
• Getting the data
• Performing an action
• Publishing the result

• The above metrics is maintained in the computer system also.
• Here we call the processes as
• Input
• Processing
• Output
• These procedures are in turn named as Input-Process-Output Cycle (I-O-P Cycle).
 Note: Data are viewed as a lowest level of abstraction from which knowledge and information are derived.

Basic Functional Components of a Computer

The various functional units of a computer system together constitute the organization of the computer. Basically a computer consists of three major units namely:
• Input Unit
• Central Processing Unit (CPU)
• Output Unit

Basic Structure of a Computer

Let us learn each section of the computer in detail

Input Unit
• It comprises of various input devices, which help to input program, data, information and various operating commands into the computer.
• The main function of input unit is to read the information contained in the program and to transfer that information to the CPU.
• The information received is converted into binary digits and stored in the computer memory
• Input devices are used to give input.
• Various input devices are
• Keyboard
• Mouse
• Joystick
• scanners
• Magnetic Ink Character Reader (MICR)
 Note: Input device is that any machine that feeds data into a computer.

Central Processing Unit

• Central Processing Unit (CPU) forms the heart of a computer system.
• CPU is the control centre for a computer.
• Memory unit, Arithmetic Logic Unit (ALU) and control unit together constitutes CPU.
• As soon as the program is fed into the input unit, the control unit gives necessary signals to the memory unit. Then the relevant data is sent to Arithmetic Unit.
• The various units are discussed below
• Arithmetic Logic Unit: Performs all types of operations such as addition, subtraction, multiplication and division as well as logical comparison.
• Memory Unit: It is the main part of the computer where the program, data, instruction, certain software and results were stored. They can be retrieved at any time whenever required.
• Control Unit: The control unit controls the operation of all the other units of a computer. It has a direct control over the input and output units.
 Note: Memory Unit is otherwise called as storage unit, primary memory.

Output Unit

• The results of computations from the memory unit were taken to the output unit and the results were shown in a human understandable language.
• Output device helps to give results to the outside user of the computer system.
• Output devices such as
• Monitor
• Printer
• Card Punch
• Plotter
• Speech synthesizer
• Projectors
 Note: Computer is aware of only two data such as 0 and 1 called Binary Digits

Four main components of a computer

Systems to be executed properly, then the following components are essential. They are
• Hardware
• Software
• Operating System
• User

Basic components of a computer

Hardware

• Hardware is the physical parts of a computer.
• As it is distinguished from the data it contains or operates on, and the software that provides instructions for the hardware to use it.
• It can be touched and seen.
• All the input and output devices compromises a hardware
• Example - Monitor, Keyboard, mouse, printer and other peripherals.

Software

• Set of instruction used to execute or to operate a computer.
• Instructions are given in the form of bits and bytes.
• Software is divided into 3 major categories.
• They are
• System Software - It helps in running the computer hardware and computer system. It includes
• Device driver
• Server
• Utilities
• Windows System.
• Application Software - It allows the end user to accomplish one or more specific task. It includes
• Air ticket booking
• Net Banking
• Online shopping
• Computer Games
• Programming Software / Language Processors - It is used to assist the programmer in writing computer programs and software using different programming languages. It includes
• Complier
• Debugger
• Interpreters

Operating System

• An operating system is a program which acts as an interface between a user and the hardware.
• It controls all the components of the computer system.
• Various operating systems are
• Windows 95/98/2000
• Windows XP
• Unix
• Linux
• Windows Vista

User

• Person who uses a computer or an internet service.
• Users are of two types, namely
• Single user
• Multi user