Click Start Learner's Book 6

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Click Start

INTERNATIONAL EDITION

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Learner’s Book 6

Third edition

Digital Access

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University Printing House, Cambridge CB2 8BS, United Kingdom One Liberty Plaza, 20th Floor, New York, NY 10006, USA 477 Williamstown Road, Port Melbourne, VIC 3207, Australia 314–321, 3rd Floor, Plot 3, Splendor Forum, Jasola District Centre, New Delhi – 110025, India 79 Anson Road, #06–04/06, Singapore 079906 Cambridge University Press is part of the University of Cambridge.

It furthers the University’s mission by disseminating knowledge in the pursuit of education, learning and research at the highest international levels of excellence.

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www.cambridge.org Information on this title: w ww.cambridge.org/9781108951906 © Cambridge University Press 2011, 2014, 2020

This publication is in copyright. Subject to statutory exception and to the provisions of relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press.

First published 2011 Second edition 2014 Third edition 2020

20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 ISBN 9781108951906

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Cambridge University Press has no responsibility for the persistence or accuracy of URLs for external or third-party internet websites referred to in this publication, and does not guarantee that any content on such websites is, or will remain, accurate or appropriate. Information regarding prices, travel timetables, and other factual information given in this work is correct at the time of first printing but Cambridge University Press does not guarantee the accuracy of such information thereafter. notice to teachers

The photocopy masters in this publication may be photocopied or distributed [electronically] free of charge for classroom use within the school or institution that purchased the publication. Worksheets and copies of them remain in the copyright of Cambridge University Press, and such copies may not be distributed or used in any way outside the purchasing institution.

Every effort has been made to trace the owners of copyright material included in this book. The publishers would be grateful for any omissions brought to their notice for acknowledgement in future editions of the book.

Introduction

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The international edition of Click Start: Computing for Schools is designed around the latest developments in the field of computer science, information and communication technology. Based on Windows 7 and MS Office 2010, with extensive updates on Windows 10 and MS Office 2016, the series aids the understanding of the essentials of computer science including computer basics, office applications, creative software, programming concepts and programming languages.

Each level of the series has been designed keeping in mind the learning ability of the learners as well as their interests. Efforts have been made to use examples from day-to-day life, which will help the learners to bridge the gap between their knowledge of the subject and the real world. The books are designed to offer a holistic approach and help in the overall development of the learners.

KEY FEATURES

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• Snap Recap: Probing questions to begin a chapter and assess pre-knowledge • Learning Objectives: A list of the learning outcomes of the chapter

• Activity: Interactive exercise after every major topic to reinforce analytical skills and application-based learning

• Exercise: A variety of questions to test understanding • Fact File: Interesting facts to improve concept knowledge • Quick Key and Try This: Shortcuts and useful tips on options available for different operations • Glossary: Chapter-end list of important terms along with their definitions • You Are Here: Quick recap

• Lab Work: Practical exercises to enable application of concepts through learning-by-doing

• Project Work: Situational tasks to test practical application of the concepts learnt • Who Am I?: Biographies to inspire young learners

• Sample Paper: Practice and preparation for exams • Poster: Informative infographics to help students stay safe in a connected digital environment

The aim of this book is to make learning fun and to help the learners achieve expertise in this fast-changing world of computer science.

MS Powe

Overview

1. What is the importance Snap Recap of creating a presentation?

M S Po wHow ercan Poyou 2.

Probing questions to inadd t ,20 mod10 ify and– save a PowerPoint presenta tion? begin a chapter and 3. How can you add grap hics to your presentation? assess pre-knowledge 4. What is slide tran

ng

Formatting Cells

You can also change the pattern and the background colour of the cells in a worksheet. You need to follow the steps given below.

1. Select the cell or range of cells.

2. Right click the mous e and select Format Cells... option from the shortcut menu.

3. The Format Cells dialo g box appears. Click on the Fill tab (Fig. 6.4).

sition?

Activity Interactive exercises • Inventory managemen t, payroll system, Financial a after every major topic to ccounting , Hotel man agement, etc. reinforce analytical skills and • GIMP, Photoshop, Win dows Movie Maker, etc. application-based learning • MS Access, Sybase

s are text editor used for t files, backup utility tha t up of disks, compression mpression of files, disk that attempts to minimise e disk, and anti-virus virus-free environment.

FACT FILE

The open source applica tion software provides the sou rce code along with the .exe file so that users can mak e changes in the code to suit their requirements. The open source substitute of MS Office is OpenOffice.

Fact File Interesting facts to nly used utility softwares. improve concept n source application soft wares. olution of computer knowledge languages. Classify them based on whe

ther

• creatin

In MS PowerPoint 2010, you can create presentati on LEAm RNI photo albu NG pre S dify ma senOBJ tatiECT onsIVE , mo ster slide, add hyperlinks, and reuse slid You will learn about: es.

SNAP RECFill AP tab

Border tab

4. Choose the required pattern Fig. 6.4 Selecting patter n for cells and background colour for the cells from Pattern Colo r:, Pattern Style: and Background Color: sectio ns.

5. Click on OK. The chang es are reflected in the work sheet.

• MS Excel, Lotus 123

You will l • creatin • creatin • photo • applyin

Introduction

1. What is the importanc Learning Objectives e of creating a presentation?

2. How can you add, mod ify and A list of the learning save a PowerPoint presenta tion?

3. How can you add grap hics to outcomes of the your chapter presentation?

n programs which assist a ng housekeeping functio ns scanning/cleaning viruses on. They ensure the smo oth uter.

an interpreter.

Advanced Features

4. In this tab, select the style for lines of the borde r from Style: in the Line You can also choose differ section. ent colours from the Colo r: drop-down list.

5. Select the borders from Presets and Border sectio ns.

6. Click on OK button.

The borders will now appea r formatted.

• creating a presenta

tion using templates Cr eating tinagpres • crea aenta Pre ntation tionse usin g themes

Using a Templa

• photo album In MS PowerPoin • slide master • applying animationst 2010, a template is a design or a p inserting charts and slid es. These templa• tes 4. What is slide transition con ? table s tain layouts, theme colour FACT FILE bac kgrting ounhype d styl • crea es and con ten rlinks • reus t.s ing slide You can also format the cells, text, fonts, patterns, Custom templates can be and cell borders directly options given on the Ribbo from the created, stored and used n. any Introduction share these custom templa tes with other users. Som ef online for use.

In MS PowerPoint 2010, you can create pres

entations using templates photo album presentation or themes, create s, modify master slide, add custom animations, char hyperlinks, and reuse slide ts, tables, s.

AC TIVITY

Design a spreadsheet for Inter-section ‘Soft board competition list’ with the Topic, Class, Section, Judge columns: 1 marks, Judge 2 marks, Judge 3 marks, Total marks Remarks. Use all the forma and tting features learnt so far and make your spreadshee and presentable. t attractive

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ment System

SNAP RECAP

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age

Adva Fea

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YOU ARE HERE

Creating a Presentati

1. An operating system performs several basic function s.

2. When you switch on a computer, the operatin g system is loaded onto the RAM

automatically in a specific sequence. on Using54 An operating system does 2 pla3. te a Tem the job of a system

manager and performs the following important function In MS PowerPoint 2010, s: process management, device management, memory management, file a template is a design or management and houseke eping.

4. In CUI,athepatt ern slides. These templates cont operatin of g system a slide provide or s an grou environ p theofuser needs to type a ment where ain layouts, theme comma nd to perform a particular action. For example, Disk colo urs, them operating system. background styles and cont 5. In e provide font GUI, the s, operatin them g system e effe cts, s a graphical ent. perform an action by just

environment where the user

a mouse-click. For

can

example, Windows operatin 6. In Windows, after comple g system.

Custom templates can be ting the work, operating system files are sent back disk properly to prevent created, stored and used to the hard damage. This process is shut down of an operatin system.any number of time share these custom templat g s. known Youascan also es with other users. Som e free templates are also online for use. available

EXERCISE A.

54

Exercise A variety of questions to test understanding

State whether true or false.

1. Pressing on the Power button when the compu ter is switched off is called warm boot.

2. An operating system sends output to the display screen.

3. When the system is switche d on, then the BIOS loads onto the RAM. 4. Multi-user operating system is selected when one user needs to do one thing at a time.

5. An operating system is an

B.

application software.

Circle the odd one out from the following.

1. DOS Windows 2. Housekeeping Process management 3. MBR BIOS 4. Switch user Lock

MBR Device management RESTART

Mac Booting POST

4. You can enter the de sired text in the header are 25 a. You can also change the and the position of the he alignment ader.

5. Click on the Footer drop-down list in the In sert tab to insert a footer cursor will blink in the foo . Now, the ter area of the document.

6. Select aQuick style froKey m the Page Number TRY THIS drop-down in the Header & Fo and Try This oter group of the Insert tab to insert Click on Go to Header page numbers in and Go to the docuShortcuts ment. Click and Footer options, respectiv on the Close Header ely, in the & Footeuseful r optiontips Navigation group of the in theon Close group of the De sign Design tab. tab to move between

options available for Footnotedifferent s and Enoperations dnotes

and footer areas.

CUI

Sleep

the header

Footnotes and endnotes in MS Word are used for adding notes, comments, references for text in a do or to provide cument (Fig. 3.3). In ge neral, footnotes are detai and printed at the bottom led comments of a page to give extra inf ormation about something been written on that page that has . On the other hand, the endnotes are for citation and they are displayed at of sources, the end of the document.

•

Sleep: It puts the compu ter in a low-power state and saves the work being that it can be resumed from done so the point where it was left off.

FACT FILE Like Sleep in desktop PCs, Hibernate is a power-saving mode developed for laptops. keeps the active docume It nts and programs running on the hard disk and puts in low-power state so that the computer work can be resumed quickly . This allows the users to work even in case of power restore failure.

AC TIVITY Read more about mobile operating systems. List the various mobile OS availabl market. e in

the

GLOSSARY BIOS A built-in softwar e into a computer’s RAM. Booting It is a process that starts the operating system when the user turns system. on a computer Cold boot It is the process of pressing on the Power button when the comput MBR It is the informa er is shut down. tion that BIOS copies onto the RAM. Multi-user operating system It supports multiple users at the same time and/or different times.

Operating system It is a system software that is an interface between the user and the computer.

POST Power-On Self Test conducted by BIOS to make sure all the compon computer are in a working ents of the condition.

Single-user operating system It is a system where only one user can effectively work on a computer at a time.

Warm boot It is the process of pressing the Restart button while the computer is already on.

Glossary Chapter-end list of important terms along with their definitions

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2. How are computers classified on the basis of their size and speed?

3. Differentiate between the two types of primary memory available in computers.

4. What is the use of plotters? Also, describe the various types of plotters.

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5. Differentiate between a compiler and an interpreter.

LAB WORK

1. An operating system performs several basic function s.

2. When you switch on a computer, the operatin g system is loaded onto RAM automatically in a the specific sequence.

3. An operating system does the job of a system manager and performs the following important function s: process management, device memory management, How are computers classified onfilethe basis of their size and speed? management, manage ment and housekeeping.

4. In CUI, the operating system provides an environm ent where command to the user needs Differentiate between the two types of primary memory available perform a particul to type ain computers. ar action. For example, Disk operating system.

5. In GUI, the operating system provides a graphica Whatperform is theanuse of by plotters?

Also, describel environm the various types ofcan plotters. ent where action the user just a mouse-click. For example , Windows operating system.

6. In Windows, after complet the work, and operatin Differentiate between a ing compiler ang system interpreter. files are sent back to the disk properly to prevent damage. This hard process is known as shut system. down of an operating YOU ARE HERE

2

2.

3.

4.

5.

EXERCISE

when one user needs

one thing at a time. to do 4. What is the use of plotters? Also, describe the various types of plotters.

5.

B.

You Are Here Quick recap

5. An operating system is

an applicat ion softwar Differentiate between a compiler ande.an interpreter.

Circle the odd one out from the following.

1. DOS Windows MBR 2. Housekeeping Mac Process management Make a presentation on ‘Classification of Computers’.

Write about the important Device manage ment Booting 3. MBR BIOSof the computer. Take help of the internet to make the features and use of each type RESTART 4. Switch user POST Lock presentation and insert wherever possible.

Make the alast slide of presentation CUI A. Search more pictures about early calculating devices.

Make presentation describing Sleep

PROJECT WORK

LAB WORK

Search more about early calculating devices. Make a presentation describing technology used in the devices.

Secondary memory is available in the form of storage devices. Find out the important features of a few secondary storage devices available in the market these days and make a report or a presentation. Take help of the Internet, library resources, etc.

Make a presentation on ‘Classification of Computers’. Write about the important features and use of each type of the computer. Take help of the internet to make the presentation and insert pictures wherever possible. Make the last slide of presentation as bibliography or credits and put the URLs of all the sites from where you have collected the information.

Project Work Situational tasks to test practical application of the concepts learnt

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as bibliography or creditsused and in putthethedevices.

URLs of all the sites from where you have collected technology the information.

B. Secondary memory is available in the form of storage devices. Find 25 out the important features of a few secondary storage devices available in the market these days and make a report or a presentation. Take help of the Internet, library WHO AMetc.

I? resources, I was born on 1 June, 1956.

I have designed operating system 86-DOS for the Intel 8086 with Seattle Computer Products.

I am also known as ‘The Father of DOS’.

PROJECT WORK I am ..................................................................... .

Make a presentation on ‘Classification of Computers’. Write about the important features and use of each type of the computer. Take help of the internet to make the presentation and insert pictures wherever possible. Make the last slide of presentation as bibliography or credits and put the URLs of all the sites from where you have collected the information.

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B.

PROJECT WORK

LAB WORK A. Search more about early calculating devices. Make a presentation describing A. State whether true or false. technology used in the devices.

1. Pressing on the Power button when the form of storage devices. Find out the B. Secondary er is switched off is called memory warm boot.is available in thecomput important features of a few secondary storage devices available in the market 2. An operating system sends output topresentation. the display screen. these days make a report or aon Internet, library 2.

How areand computers classified the basis ofTake theirhelp size of andthe speed?

3. When etc. the system is switched on, resources, then the BIOS loads onto the RAM. 3. Differentiate 4. Multi-user between the two types of primary memory available in computers. operating system is selected

A.

Lab Work WHO AM I? Practical exercises to enable application of concepts through learning-by-doing

I was born on 1 June, 1956.

I have designed operating system 86-DOS for the Intel 8086 with Seattle Computer Products.

I am also known as ‘The Father of DOS’.

I am ..................................................................... .

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Sample

WHO AM I?

I was born on 1 June, 1956.

I have designed operating system 86-DOS for the Intel 8086 with Seattle Computer Products.

I am also known as ‘The Father of DOS’.

I am ..................................................................... .

Sample Paper Practice and preparation for exams

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Who Am I? Biographies to inspire young learners

Paper

Tick ( ) the correct option.

1. Match the technologies given

in Column-I with their

Column-I A. B.

Transistor Vacuum tube

C.

Microprocessor

D.

Integrated circuit

a. A.-i., B.-ii., C.-iv., D.-iii. c. A.-ii., B.-i., C.-iii., D.-iv.

2. Which of the followi ng

generations in Column -II.

Column-II i. ii.

First generation Second generation

iii. Third generation iv.

Fourth generation b. A.-ii., B.-i., C.-iv., D.-iii. d. A.-ii., B.-iii., C.-iv., D.-i.

is not a system softwar e?

a. MS PowerPoint b. Linux c. Unix d. Windows 7 3. Select the correct sentenc e(s) with reference to booting process in computer. i. Booting is a process that starts the operating system when the user turns on computer system. a ii. Warm boot is pressing the Power button while the computer is already iii. Cold boot is pressing on. the Restart button when the computer is switche a. Only i. d off. b. Only i. and ii. c. Only iii. d. i., ii. and iii.

4. BIOS is a built-in softwar e into a computer’s RAM. What is its full form? a. Basic Input Output Softwar e b. Biased Input Output c. Basic Input Output Standar System d d. Basic Input Output System

159

Don’t pretend to be someone else online.

Tell an adult if you are being cyberbullied.

Never open suspicious emails, links, messages, etc. from unknown people.

© Cambridge University Press

2011, 2014, 2020

Never share your account passwords, even with your friends.

Avoid posting or sharing hurtful or threatening messages on social networking sites.

Report and block cyberbullies who send you hurtful messages.

Save any evidence of the bullying that can be reported.

Don’t share any personal info online or in texts that could humiliate you.

Poster Informative infographics to help students stay safe in a connected digital environment

C ntents 01 Know Your Computer ���������������������������������������������������� 1

07

02 Operating System ��������������������������������������������������������� 19

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°° Booting °° Functions of an operating system °° Types of operating system

°° Operating system interface °° Importance of shut down

03 MS Word 2010 – Advanced Features ������������������������� 29 °° °° °° °° °° °° °°

Headers and footers Footnotes and endnotes Drop Cap Tab Stop Using Show/Hide tool Format Painter Columns

°° °° °° °° °° °°

Changing Changing indentation Thesaurus Borders and Shading Page setup and margins Applying built-in styles

°° Creating the merged document °° Previewing your documents

05 MS PowerPoint 2010 – Advanced Features ��������������� 54 °° Creating a presentation using a Template °° Creating a presentation using Themes °° Photo Album °° Slide Master

°° Applying animations °° Inserting charts and tables °° Creating hyperlinks °° Reusing slides

06 More About MS Excel 2010 ���������������������������������������� 71 °° Formatting numbers °° Modifying data °° Formatting data

°° Changing the Backdrop of the Stage °° How to use the Costumes tab

Introduction to QB64 ������������������������������������������������� 100 °° Components of the QB64 window °° Writing and executing a program

09

10

°° Creating Custom Lists °° Formulas and functions °° Function Library

Character set Constants Variables PRINT statement

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°° LET statement °° INPUT statement °° REM statement

QB64 – Programming Statements ���������������������������� 118 °° Sequential statements

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°° Saving a program °° Opening a program °° Exiting QB64

QB64 – Statements ����������������������������������������������������� 109 °° °° °° °°

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04 MS Word 2010 – Mail Merge �������������������������������������� 46 °° Mail Merge °° Uses of Mail Merge °° Creating the Main Document

°° Types of blocks °° Block categories °° Using Scratch blocks

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°° Early calculating devices °° Functional components of a computer °° Evolution of computers Classification of °° °° Categorisation of software computers

More About Scratch ����������������������������������������������������� 86

°° Conditional statements

Introduction to Macromedia Flash �������������������������� 129 °° °° °° °°

Starting Flash Flash tools panel Gradient effects Key terms

°° Animation in Flash °° Creating an animation of a bouncing ball °° Symbols

Introduction to Email ������������������������������������������������ 145 °° Uniform Resource Locator (URL) °° Email °° Advantages of email °° Disadvantages of email °° Creating and opening an email account

°° °° °° °° °°

Composing an email Replying to an email Forwarding an email Chatting with a contact Signing out from an email account

Sample Paper �������������������������������������������������������������� 160

Know Your

SNAP RECAP

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Computer You will learn about: • early calculating devices • the evolution of computers • classification of computers • functional components of a computer • categorisation of software.

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1. What are the features of a computer that make it more efficient than a human being?

2. What is meant by the Input-ProcessOutput cycle?

3. How is data stored in computers? What is meant by primary and secondary memory?

4. What are computing devices?

LEARNING OBJECTIVES

Introduction

A computer is an electronic device that accepts data from the user, processes it and gives the desired output. It is a machine capable of performing calculations with the help of a mechanical computing device. The evolution of computers started back in the late 1930s.

Computers at that time used only binary language for their operations.

Early Calculating Devices

A few calculating devices used prior to the development of computers are discussed here.

Abacus The abacus, the first calculating machine, was developed in China.

It was used to count numbers and perform simple calculations such as addition and subtraction.

Abacus

1

Napier’s Bones Napier’s Bones was developed by Sir John Napier and released in 1617. The device was used to perform calculations involving addition, subtraction, multiplication and division. It was named so because the numbers were carved on bones or strips of wood.

Napier’s Bones

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Pascaline

Pascaline, one of the first mechanical calculators, was invented by Blaise Pascal in the year 1642.

Though it could perform only addition and subtraction, it still became very popular.

Pascaline

Difference Engine

The Difference Engine was designed by Charles Babbage in the year 1822. It was an early digital device which could perform mathematical and astronomical calculations.

It was also capable of storing data temporarily and printing the output.

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Analytical Engine

The Analytical Engine was designed by Charles Babbage in the year 1837. It was the first mechanical general purpose computer which followed a typical IPO cycle used in modern computers. The machine took input using a reader as an input device. It was made up of ‘mill’, the calculating unit like the CPU in modern computers.

Evolution of Computers

From everyday tasks to moving satellites in space, computers have revolutionised almost everything in our society. The development of computers has been classified into generations. You will now learn more about these.

First generation computers (1940–1956) – vacuum tube In the evolution of computers, the first generation was characterised by the use of vacuum tubes. The first generation computers were built to solve physics equations

2

using electronic vacuum tubes as switching components. These used machine language. A machine language is a low-level programming language and is written using long strings of 0s and 1s for computing. Machine language varies with the computer used.

FACT FILE

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The first generation computers were expensive and bulky. The vacuum tubes did not support multitasking. Programs written in machine language were complicated and difficult to remember.

Vacuum tubes

The Universal Automatic Computer (UNIVAC) and Electronic Numerical Integrator and Computer (ENIAC) are examples of first generation computing devices. The UNIVAC was the first commercial computer.

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Second generation computers (1956–1963) – transistor In the 1960s, transistor-based computers replaced vacuum tubes which marked the second generation of computers. Transistors made computers smaller and cheaper. They also made computers energyefficient, but the transistors were subject to damage because of the emission of large amounts of heat from the computer.

Computers belonging to this generation used punched cards for input. They used assembly language, which is a low-level programming language. This language is based on the English alphabet. The instructions are written in the form of codes. The assembly language was machine dependent, and had to be written based on the configurations of the computer.

Various transistors

3

Third generation computers (1964–1971) – integrated circuit Integrated circuit computers marked the third generation of computers. Small transistors were placed on silicon chips, called semiconductors, which increased the speed and efficiency of computers.

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The third generation computers were based on high-level languages. A high-level language uses the English alphabet and mathematical symbols. It was easy to use and understand. It was not machine dependent. The programs written in a high-level language are called source programs. Fortran, COBOL, BASIC, C, C++, Java are a few examples of high-level languages.

Integrated circuit chip

Fourth generation computers (1971–2010) – microprocessor

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The introduction of microprocessors was the hallmark of fourth generation computers. They facilitated automation of industrial and office processes.

Around 1970, this technology of placing thousands of integrated circuits onto a single silicon chip, that made up a microprocessor, was made available.

A microprocessor is compact and easy to maintain.

It has a high processing speed. However, it has limitations on the size of data.

Microprocessor

FACT FILE

A microprocessor is a multipurpose, programmable device that takes input and provides output. Intel 4004 was the world’s first commercially available microprocessor. It was the first complete CPU on one chip designed by Intel Corporation.

Fifth generation computers (2010 onwards) – artificial intelligence The development of fifth generation computers is underway. They are based on the principles of artificial intelligence and natural language recognition. This technique will be used to design robots.

Developers are aiming at developing computers capable of organising themselves. So, the evolution of computers still continues.

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Classification of Computers On the basis of their size and speed, computers are generally classified as: 1. Microcomputer 2. Mainframe computer

3. Minicomputer 4. Supercomputer

Microcomputer

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Microcomputer was a commonly used term for personal Fifth generation computers computers. A personal computer assemblage consists of a CPU, computer memory (primary and secondary) and various input and output devices. Only one person can use it at a time. It is much slower and has less storage capacity than a minicomputer or a mainframe computer. It is commonly used in classrooms, homes, banks, universities, etc.

There are various kinds of microcomputers available. These are shown below.

Desktop PC: A microcomputer designed to fit

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comfortably on top of a desk, typically with the monitor in front and the system unit on the side.

Laptop: A portable microcomputer. You can use it on your lap. Laptop computers are often also called notebook computers.

Desktop PC

Laptop

Tablet: A mobile computer. It offers users a touchscreen

environment that may or may not be accompanied by a stylus (a pointing device). They are available in a variety of sizes and have a built-in/virtual keyboard.

Smartphone: A mobile phone built on

Tablet

a mobile operating system. It has enhanced features as compared to an ordinary mobile phone, such as compact digital cameras, GPS, web browsers, Wi-Fi and broadband facility.

Smartphone

5

Mainframe computer

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Mainframe computers are very large, often filling an entire room. They can store an enormous amount of information, and perform many tasks simultaneously. They can communicate with many users at the same time and are very expensive. Mainframe computers usually have several terminals connected to them. These terminals look like small computers but are only used for sending and receiving information from the main computer. Terminals can be located either in the same room with the mainframe computer, or they can be in different rooms, buildings, cities, etc.

Large businesses, government agencies, banks and universities usually use mainframe computers. Big hospitals, airline reservation companies and many other large businesses prefer mainframe computers because of their capability of processing enormous amounts of data.

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Minicomputer

Mainframe computers

A minicomputer is much larger than a microcomputer and much more expensive. It lies between microcomputers and mainframe computers and is often referred to as a midrange computer. It possesses most of the features found on a mainframe computer, but on a limited scale.

It can still have many terminals, but not as many as the mainframe. It can store a large amount of information, but not usually as much as the mainframe computers. It uses an enhanced instruction which can support scientific processing and commercial applications. Medium and small businesses and colleges typically use minicomputers.

Supercomputer

DEC PDP-8 minicomputer

Supercomputers are one of the many types of modern computing machines, which are big, powerful and capable of doing very speedy calculations. It is because of their

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high-speed processing ability that supercomputer systems are used in graphic animation, weather forecasting, nuclear research works, petroleum research, crypt analysis, molecular modelling, etc.

Y AC TIVIT

Supercomputer

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The difference between the mainframes and supercomputers is that while mainframe machines are primarily used for a number of purposes, supercomputers are designed to serve a single purpose.

A. Search for more information about application areas of minicomputers, supercomputers and mainframe computers. Document your findings using MS Word.

Ensure that you have included at least five applications for each type of computer.

B. Make a chart of early calculating devices along with their inventors and their uses.

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Functional Components of a Computer

The functional components of a computer are shown in the diagram below.

Input Unit

Central Processing Unit (CPU)

Output Unit

Functional components of a computer

The input and output units attached to a computer are called computer peripherals.

Input unit

Data is accepted by a computer through the input unit connected to it. The standard input device is a keyboard. Examples of other input devices are joysticks, mice, web cameras, Magnetic Ink Character Recognition Readers (MICR), Optical Mark Recognition Readers (OMR), Optical Character Readers (OCR), touchscreens, smart card readers, digital readers, etc.

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You have already read about some of the commonly used input devices in earlier books.

Some other input devices are described below.

Bar code reader: This is used by a computer to scan and

FACT FILE

Bar code reader

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identify the product or item codes in supermarkets, book stores, and many other places. The code for each item, such as the price code, item code, etc., is a unique combination of vertical bars and can be identified by a bar code reader.

Quick Response (QR) codes are special barcodes that can be read using QR reading devices, mainly installed as an application on smartphones. These codes link the user directly to text, emails or websites.

Magnetic Ink Character Recognition (MICR) Reader: This reads the special characters printed using

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a special magnetic ink. Cheque number, bank code and branch code are printed on cheques using magnetic ink, making them difficult to forge. The MICRs scan this information and are therefore capable of sorting cheques.

Magnetic Ink Character Reader

Optical Mark Recognition (OMR) reader: Used

for recognising a pre-specified space on a paper that is marked by a pencil or pen. It is commonly used for marking the answers on examination sheets.

An OMR sheet

Central Processing Unit

The Central Processing Unit (CPU) is the control centre of a computer. It guides, directs and governs its performance. It is known as the brain of the computer. The CPU has three components which are responsible for different functions. These are discussed here.

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Arithmetic Logic Unit (ALU): The ALU performs all arithmetic and logical operations within a computer. This part provides the arithmetic and decision-making capability to a computer.

Control Unit (CU): The CU controls and guides the interpretation, flow and manipulation of all data and information. The CU sends control signals until the required operations are completed by the ALU and the memory.

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Another important function of the CU is program execution, that is, carrying out all the instructions stored in the program. The control unit even controls the flow of data from the input devices to memory and from memory to the output devices.

Memory Unit (MU): The MU is that part of the computer where the data is stored

and is accessible to the CPU. The various measurement units of computer memory are given here.

1.

Bit: A bit means a binary digit, that is, there are only two possibilities for each digit, either 0 or 1. A bit is an elementary unit of computer memory.

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A number of bits when combined together in different ways are used for storing data in a computer.

2. Byte: A group of 8 bits is called a byte. One byte is the smallest unit which can represent a meaningful data item or character in a computer. Memory is generally measured in terms of bytes.

3. Nibble: A group of 4 bits is called a nibble.

The computer memory can also be expressed in other units and their interrelationship is given below:  

1 Byte

1024 Bytes

= 8 Bits

1024 Terabyte (TB) = 1 Petabyte (PB)

= 1 Kilobyte (KB)

1024 Petabyte (PB) = 1 Exabyte (EB)

1024 Kilobyte (KB) = 1 Megabyte (MB)

1024 Exabyte (EB) = 1 Zettabyte (ZB)

1024 Megabyte (MB) = 1 Gigabyte (GB)

1024 Zettabyte (ZB) = 1 Yottabyte (YB)

1024 Gigabyte (GB) = 1 Terabyte (TB)

FACT FILE

1 kilobyte is equal to 1024 bytes and not 1000 bytes as it is 2 raised to the power 10.

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The computer memory is classified as shown in the diagram below.

Memory Primary Memory RAM

ROM

Secondary Memory Compact Disc

Hard Disk

Flash Drive

Primary memory

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The Memory Unit

Primary memory is the basic requirement of a computer. It determines the size and number of software applications that a computer can store. Primary memory stores two types of programs: system software and application software. You will learn more about them later in this chapter.

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Primary memory limits the amount of data that a computer can process. The CPU can use this memory directly while processing information. On the basis of volatility of storage of data, primary memory is classified into volatile memory (RAM) and nonvolatile memory (ROM) as shown in the table below.

Differences between RAM and ROM

Random Access Memory (RAM)

Read Only Memory (ROM)

1. Temporary memory.

1. Permanent memory.

2. Volatile in nature, that is, the information stored in RAM is designed to clear when the computer is turned off.

2. Non-volatile memory, that is, the information stored in ROM is retained even when the computer is turned off.

3. The main internal storage area that a computer uses to run programs and store data. It is also called read/write memory.

3. Built-in computer memory that can be read by a computer but cannot be modified. It is a memory unit that can only be read.

Secondary memory Secondary memory is also known as auxiliary memory. It is used for storing data or programs on a temporary or permanent basis. The secondary memory is available in the

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form of storage devices. For example, hard disks, compact discs (CDs), flash drives, etc.

FACT FILE

Storage devices

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The CPU cannot access secondary memory directly while processing information. The data is transferred to the primary memory when required. The computer uses its input and output devices to access data stored in the secondary memory.

Cache memory can be used for increasing the capacity of the primary memory and to make the processing faster.

Output unit

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The Output Unit is for getting information from a computer. For example, the Visual Display Unit (VDU) or the monitor is an output device that displays the information on the screen. The information shown on a display unit is called a soft copy. Speakers are the output devices which produce output in the form of audio. You can also obtain information from a computer on a physical medium, such as paper, with the help of a printer. Printed information is called a hard copy.

Other output devices are described below.

Liquid Crystal Display (LCD) projector: Output from a computer can also

be viewed on a large screen or flat surfaces other than the monitor using an LCD projector.

It is usually used for showing PowerPoint presentations in schools and businesses.

LCD projector

Plotters: These are the output devices used for making high-quality graphics, charts, diagrams, maps, etc. Plotters use an ink jet or ink pens to create the required output on paper.

There are different types of plotter available. The three basic types of plotter are:

Inkjet plotter: This sprays small droplets of ink onto a piece of paper and creates 1. an image.

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2. Flatbed plotter: The pen or the inkjet moves in horizontal and vertical directions over a fixed horizontal flat surface on which paper is mounted.

Inkjet plotter

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3. Drum plotter: This uses a drum revolver or roller to move the paper and the pen or the jets of the ink during the printing process. The paper is placed over the drum which is then rotated. The pen is moved along the horizontal or vertical direction to print the output.

Flatbed plotter

Drum plotter

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A. Make a list of the latest input, output and storage devices available.

B. What are flash drives used for? Find out the range of their storage capacities.

C. Using the internet, find out the various storage capacities of RAM available.

Categorisation of Software

Software is a set of programs that runs a computer system. Computer software is stored and executed (run) with the help of computer hardware. Major categories of software that form part of a computer system are discussed here.

System software

FACT FILE Computers work on the theory of GIGO (Garbage In Garbage Out). It means that wrong input will give the wrong output.

System software is a program that manages and supports the resources and operations of a computer system while it executes various tasks such as the processing of data

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and information, controlling the hardware components and allowing users to use the application software. In other words, system software is a bridge between the computer system hardware and the application software. An Operating System (OS) is an example of system software.

System software controls the internal computer operations. It can be further classified into two categories.

Operating System (OS): An operating system is software which acts as an

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interface between the user and the computer (that is, all computer resources). It is an important component that controls all other components of the computer system.

Without an operating system, a computer will not work. Some of the most commonly used operating systems are Windows, DOS, UNIX, etc.

Language translators: These are used to translate programming languages. There are three types of language translators.

Compiler: Translates the high-level language program into machine language. It converts the entire program in one go and reports all the program errors along with their line numbers. For example, C language uses a compiler. The translated program is called the object program or the object code.

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Interpreter: Translates a program written in high-level language into machine language by converting and executing it line by line. If there is an error in any line, the interpreter reports it immediately and the program cannot continue until it is fixed. However, it is a smaller program than a compiler. For example, BASIC uses an interpreter as the translator.

Assembler: A language translator that converts a program written in assembly language into machine language.

Application software

Application software is a set of programs necessary to carry out operations for a specified application. These are the programs written by programmers to enable computers to perform a specific task. Various application software and their examples are given below.

Application Software

• Word processors

• MS Word

• Presentation tool

• MS PowerPoint

Example(s)

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• MS Excel, Lotus 123

• Database management system

• MS Access, Sybase

• Business software

• Inventory management, payroll system, financial accounting, hotel management, etc.

• Image/video editing

• GIMP, Photoshop, Windows Movie Maker, etc.

Utility software

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• Spreadsheet package

Utilities are application programs which assist a computer by performing housekeeping functions like backing up disks, or scanning/cleaning viruses or arranging information. They ensure the smooth functioning of a computer.

Some important utilities are:

FACT FILE

The open source application software provides the source code along with the .exe file so that users can make changes in the code to suit their requirements. The open source substitute of MS Office is OpenOffice.

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• the text editor used for creating and editing text files • backup utility that facilitates the backing-up of disks • compression utility that facilitates compression of files • disk defragmentation utility that attempts to minimise the fragmentation on the disk • and anti-virus software that ensures a virus-free environment.

Y AC TIVIT

A. Make a list of commonly used utility softwares.

B. Read more about open source application softwares.

C. Make a chart on the evolution of computer languages. Classify them based on whether they use a compiler or an interpreter.

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GLOSSARY

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Abacus The first calculating machine that performed simple arithmetic calculations.

Analytical engine The first mechanical general purpose computer which follows the typical IPO cycle used in modern day computers.

Application software A set of programs necessary to carry out operations for a specified application.

Assembler Converts a program written in assembly language into machine language.

Assembly language A low-level programming language which uses English words.

Bit A binary digit.

Byte A group of eight bits.

Compiler A language translator that translates high-level language programs into machine language.

Desktop A computer designed to fit comfortably on the top of a desk.

Difference engine An early digital device which was designed to perform mathematical and astronomical calculations.

High-level language A language that uses the english alphabet and mathematical symbols and on which the third generation of computers are based.

Interpreter A language processor which converts high-level language programs into machine language by converting and executing it line by line.

Laptop A portable computer that can be placed on your lap.

Machine language A language written using long strings of 0s and 1s for computing.

Mainframe computer A very large computer, often filling an entire room.

A commonly used term for personal computers.

Microcomputer Minicomputer A much larger than a microcomputer, and is also much more expensive.

Napier’s Bones An early device used for performing simple arithmetic calculations.

Nibble A group of 4 bits.

Operating system A software that acts as an interface between the user and the computer.

Pascaline One of the first mechanical calculators to be developed.

Primary memory Determines the size and number of software that a computer can store.

Secondary memory The memory used for storing data or programs on a temporary or on a permanent basis.

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Smartphone A mobile phone built on a mobile OS with enhanced features compared to an ordinary mobile phone.

Source program A program written in a high-level language.

Supercomputer A modern computing machine that is capable of giving speedy calculations.

System software The software that controls the internal computer operations.

Tablet A mobile computer with a touchscreen and a built in virtual keyboard.

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Utility software A set of application programs that assist the computer by performing housekeeping functions.

1. Some of the early calculating devices are the abacus, Napier’s Bones, Pascaline, Difference Engine and Analytical Engine.

2. First generation computers were characterised by the use of vacuum tubes.

They used machine language.

3. Second generation computers were characterised by the replacement of vacuum tubes with transistors. They used assembly language.

4. Third generation computers were characterised by the use of integrated circuits. They were based on high-level languages.

5. The introduction of microprocessors characterised fourth generation computers.

6. Fifth generation computers are still being developed. They will be based on the principles of artificial intelligence and natural language recognition.

7. Computers are commonly classified on the basis of their size and speed as microcomputers, minicomputers, mainframe computers and supercomputers.

8. The functional components of a computer are input unit, Central Processing Unit and output unit.

9. The CPU has three components which are responsible for different functions: ALU, CU and MU. YOU ARE HERE

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1

EXERCISE

A.

True or false?

1. The first generation of computers was based on integrated circuits.

2. Secondary memory is also known as auxiliary memory.

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3. Business software are those application programs that assist the computer by performing housekeeping functions.

4. In an inkjet plotter, the pen moves in horizontal and vertical directions.

5. Pascaline was one of the first mechanical calculators to be developed.

B. Match the following.

2. Microcomputer 3. Hardware

a. C omputers used in classrooms, homes, banks, universities, etc.

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1. Fifth generation computer

b. Based on the principle of artificial intelligence. c. Hallmark of fourth generation computers.

4. Microprocessor 5. Operating system

d. A bridge between computer system hardware and application software. e. T he physical components of the computer which you can touch and feel.

C. Give full forms of the following.

............................................................................................................................................

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1. ALU 2. OCR

............................................................................................................................................

3. MICR

............................................................................................................................................

4. LCD

............................................................................................................................................

5. VDU

............................................................................................................................................

D. Fill in the blanks.

1. ..................................................... were introduced in second generation computers.

2. ..................................................... invented Analytical Engines.

3. Third generation computers were based on ..................................................... languages.

4. Our laptops are ..................................................... computers.

5. ..................................................... is a language translator which converts assembly language to machine language.

E. Answer the following questions.

1. Name the different generations of computers.

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2. How are computers classified on the basis of their size and speed?

3. Explain the difference between the two types of primary memory available in computers.

4. What are plotters used for? Describe the various types of plotters.

LAB WORK

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5. Explain the difference between a compiler and an interpreter.

A. Search for more information about early calculating devices. Make a presentation using presentation software you have learned about in previous books, describing the technology used in the devices.

B. Secondary memory is available in the form of storage devices. Find out the important features of some of the secondary storage devices available and make a report or a presentation. Make use of the internet, library resources, etc.

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PROJECT WORK

Make a presentation on ‘Classification of Computers’. Write about the important features and use of each type of computer. Use the internet to make the presentation and insert pictures wherever possible. Use the last slide for a bibliography or credits and list the URLs of all the sites you have collected the information from.

WHO AM I?

I was born on 1 June 1956.

I designed operating system 86-DOS for the Intel 8086 with Seattle Computer Products.

I am also known as ‘The Father of DOS’.

I am ..................................................................... .

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Operating

SNAP RECAP

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System You will learn about: • booting • functions of an OS • types of OS

• operating system interface • the importance of shutting down

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1. What is an operating system?

2. Which are the most common operating systems?

3. Why do you need an operating system?

LEARNING OBJECTIVES

Introduction

Computers cannot function on their own. They require programming instructions to work and manage the system. This job is done by an operating system. An operating system is a system software. It is the interface between the user and the computer. It performs the basic tasks of a computer. These are given below.

1. It recognises input from the keyboard.

2. It sends output to the display screen.

3. It keeps track of files and directories on the disk.

4. It controls the peripheral (input and output) devices such as printers.

5. It acts as an interface between the hardware of a computer and the user.

Some of the commonly used operating systems are Disk Operating System (DOS), MS Windows, Linux, Windows NT and Mac OS.

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Booting Booting is a process that starts the operating system when the user turns on a computer. It is a self-starting process.

Types of booting

The technology that is different from its previous type is called a version. The various versions of Windows are Windows 95, Windows 98, Windows 2000, Windows ME, Windows NT, Windows XP, Windows Vista, Windows 7, Windows 8 and Windows 10.

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There are two types of booting: Warm Boot: Pressing the Restart button while the computer is already on.

Cold Boot: Pressing the Power button when the computer is switched off.

FACT FILE

The booting process

When you switch on a computer, the operating system is loaded into RAM automatically.

It follows the sequence given below. These steps are part of the booting process.

s soon as the computer is turned on, the Basic Input/Output System (BIOS) is run.

1. A This software is built into a computer’s ROM.

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BIOS starts the operating system and supports the transfer of information between hardware devices.

2. B IOS first conducts a Power-On Self Test (POST) to make sure all the components of the computer are working with a proper power supply.

he BIOS then looks for the special boot programs that will load the operating T system from the hard disk.

3. A computer may have several disks or drives. The operating system is loaded in one of the disks. BIOS first looks for a floppy disk on drive A. If there is no system disk in it (where the operating system is loaded), BIOS then looks for the system files at a specific place on your hard disk.

IOS next looks at the first sector of the hard disk, and copies the information from 4. B there to specific locations in RAM. This information is known as the Boot Record or Master Boot Record (MBR).

5. The MBR program now loads the system files of the operating system into the RAM. Once the system files are loaded, the OS is ready to take control of the system. OS remains in the computer’s memory until the power is on.

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Let us now observe the booting process as shown in the flowchart below.

Computer is switched on

BIOS checks drives for system disk

BIOS conducts POST

BIOS loads MBR

MBR program loads operating system files

Flowchart showing the process of booting

Functions of an Operating System

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An operating system does the job of a system manager. It performs various important functions as shown in the diagram below.

Functions of an operating system

Process Management

Device Management

Memory Management

File Management

Housekeeping

Various functions of an operating system

Process management

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An operating system controls and schedules the processes for execution by the CPU. It is responsible for allocating the CPU’s time to each process. For example, when you are working on an MS Word document it may cause several other background processes to begin, such as virus checks, memory management, etc.

After a job is done or a process is completed, the CPU becomes idle. After that, if there are other processes in queue, then the time is allocated to each process of the CPU. This whole system is managed to ensure maximum output from the system.

Process III

Process II

Process I

CPU

CPU process queue

Device management

Device management is an important function of an operating system. It coordinates and controls the various input and output devices attached to the system. When the system is ready to take input, the input device is made available to the user, and when the processing job is over, the output is redirected to the output device.

FACT FILE The operating system needs a software, called a device driver.

This recognises the input and the output devices attached to the computer.

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Memory management Whenever you start any application software, it gets loaded onto the system memory.

When you open any file, a copy of that file is loaded onto the memory from the disk.

This is done by an operating system. It allocates certain memory area to itself with the help of the booting process and sets aside the remaining memory for other application programs.

File management

Housekeeping

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A lot of data is stored on the hard disk. The hard disk is formed of millions of tracks and sectors. At the time of storing data on the disk, it is not compulsory that it occupies the sectors in a sequence. It is the job of an operating system to read the data from different tracks and sectors when required, and to store it in the available space.

Housekeeping includes all the services necessary to ensure the smooth operation of the computer system, like security, protection, resource accounting, back up, etc.

Types of Operating System

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Single-user operating system

As the name implies, a single-user operating system is designed so that only one user can work on a computer at a time. This is the type of operating system most people use on their desktops and laptops today. Windows, DOS and Mac OS are a few examples of a single-user operating system.

Multi-user operating system

A multi-user operating system supports multiple users at the same time and/or different times. The operating system must make sure that the requirements of the different users are balanced. It must also ensure that each of the programs they are using has sufficient and separate resources so that a problem with one user does not affect the entire community of users. For example, Linux, Unix Windows NT and Novell Netware can support hundreds and thousands of networked users.

Operating System Interface

The operating system provides a platform on which the application program runs. It provides an interface which can be classified further.

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Character User Interface (CUI) In CUI, the operating system provides an environment where the user needs to type a command to perform a particular action. For example, Disk Operating System (DOS).

Graphical User Interface (GUI)

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In GUI, the operating system provides a graphical environment where the mouse acts as a pointing device. The user can perform an action just by a mouse-click. For example, Windows operating system.

Importance of Shut Down

Windows remains in the computer memory until the power is on. When the computer is closed down, these operating system files are sent back to the hard disk so that no damage is caused to these files. This process is known as shut down of an operating system.

If you switch off the computer without giving a proper shut down command then there is a high risk of losing the data, and it may also damage the Windows operating system.

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Shut down option.

To shut down a computer properly click on the Start For other options, click on the arrow on the right of the Shut down option. It generally shows the following options: • Switch user: Switches the user without closing the programs currently in use.

• Log off: Closes all programs running on the computer. However, the computer still runs.

Using the Start menu to shut down • Lock: Locks the computer.

Work on any programs running can be resumed on unlocking the computer.

• Restart: If due to some error the computer needs to be shut down, then it can be restarted by using the Restart option. This option shuts down Windows completely and then starts it again immediately.

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•

leep: Puts the computer in a low-power state and saves any work being done so S that it can be resumed from the point where it was left off.

FACT FILE

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Like ‘Sleep’ in desktop PCs, ‘Hibernate’ is a power-saving mode developed for laptops.

It keeps the active documents and programs running on the hard disk and puts the computer in a low-power state so that work can be resumed quickly. This allows the users to restore work even in the case of a power failure.

Find out more about mobile operating systems. List the various mobile operating systems available.

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GLOSSARY

BIOS A built-in software into a computer’s RAM. Booting The process that starts the operating system when the user turns on a computer system.

Cold boot The process of pressing the Power button when the computer is shut down.

MBR The information that BIOS copies onto the RAM. Multi-user operating system An operating system that supports multiple users at the same time and/or different times.

Operating system System software that is an interface between the user and the computer.

POST Power-On Self Test conducted by BIOS to make sure all the components of the computer are in a working condition.

Single-user operating system An operating system where only one user can effectively work on a computer at a time.

Warm boot The process of pressing the Restart button while the computer is already on.

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YOU ARE HERE

2

1. An operating system performs several basic functions.

2. When you switch on a computer, the operating system is loaded onto the RAM automatically in a specific sequence.

3. An operating system does the job of a system manager and performs the following important functions: process management, device management, memory management, file management and housekeeping.

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EXERCISE

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4. In CUI, the operating system provides an environment where the user needs to type a command to perform a particular action. For example, disk operating system.

5. In GUI, the operating system provides a graphical environment where the user can perform an action by just a mouse-click. For example, Windows operating system.

6. In Windows, when the computer is given the command to close down, operating system files are sent back to the hard disk to prevent damage. This process is known as shut down of an operating system.

A. True or false?

1. Pressing on the Power button when the computer is switched off is called a warm boot.

2. An operating system sends output to the display screen.

3. When the system is switched on, the BIOS loads onto the RAM. 4. A multi-user operating system is selected when one user needs to do one thing at a time.

5. An operating system is an application software.

B. Circle the odd one out from the following.

1. DOS

Windows

MBR

Mac

2. Housekeeping

Process management

Device management

Booting

3. MBR

BIOS

RESTART

POST

4. Switch user

Lock

CUI

Sleep

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C. Give one word for the following.

1. Pressing the Restart button while the computer is already on.

2. An interface between the user and the computer.

3. A graphical environment where a mouse acts as a pointing device.

4. The process of pressing on the Power button when the computer is switched off.

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5. A process that starts the operating system when the user turns on a computer system.

D. Answer the following questions.

1. What is an operating system? What basic tasks does it perform?

2. List the steps in the booting process.

3. Explain the difference between the two operating system interfaces.

4. Why is it important to properly shut down your computer?

5. Discuss the various types of operating systems.

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LAB WORK

A. Find out the differences between the terms multi-user, multitasking and multi-processing operating systems and write the differences in a word document.

Support your answer using suitable examples.

B. Start the computer in your lab and observe the booting process. Show the booting process with the help of a flowchart.

PROJECT WORK

Make a presentation on the functions of an operating system. Try to find more information about each function mentioned in the chapter. Use the internet and insert pictures wherever possible. Use the last slide for a bibliography or credits and put the URL of all the sites you have collected the information from.

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Linux is a Unix-like operating system designed by Linus Torvalds. It was released on 5 October 1991, when Torvalds was still a student at the University of Helsinki, Finland.

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Some popular Linux distributions are Fedora by Red Hat Enterprise, Mandriva, open SUSE, Arch Linux and Ubuntu from Canonical. More than 90 percent of the world’s 500 fastest supercomputers, including the top ten fastest supercomputers, run on some variant of Linux.

Some key features of Linux are:

• Free and open source – Linux is an open source operating system software, that is, it is free to use, modify and distribute both commercially and non-commercially. Anyone with licenses such as the GNU General Public License can modify and improve the program as per their own requirement.

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• Multitasking and multi-user – Linux is also a multitasking and multi-user operating system. Therefore, many people can run many different applications on one computer at the same time using their unique Login ID and Password.

• Multi-platform – Linux operating system can run on many different computer platforms.

• Secure – Linux is one of the most secure operating systems. File access permission systems prevent access by unwanted visitors or viruses. Every user needs their own user ID and password.

• Portable – A Linux kernel and application program can be installed on any kind of hardware platform.

• Hierarchical file system – Linux provides a standard file structure in which files are arranged.

• Shell – Linux provides a special interpreter program which is used to execute commands of the operating system.

Components of Linux

Major components of Linux are:

1. Hardware: Consisting of all peripheral devices like RAM, CPU, etc.

2. Kernel: The main part of an operating system. It performs the task of creating and maintaining the Linux environment. It acts as an interface between the hardware

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User 1

Application n

a nd the shell. It also controls the hardware, CPU, memory, hard disk, network card, etc. attached to the computer.

ica tio

Com

piler

s

Shell

a.out

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Ap

pl

Kernel User n 3. Shell: A program that acts as a command Hardware interpreter, which is an rs pile vi editor interface between the user Com User 2 and the operating system.

It interprets the commands cd grep entered by the user and passes them to the kernel.

User 3 There are a number of different shells available like Bourne shell (sh), Korn shell (ksh), C shell (csh). Each provides a slightly different interface between the user and the Linux operating system.

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4. Utilities and Application Programs: These are the programs like word processors, spreadsheets and database management systems that are supported by Linux environment.

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