Computer 8 New

Book 8 Revised by Krishna K. Shrestha Oasis Radiant Computer Science Oasis Publication (P) Ltd. Anamnagar, Kathmandu Phone :0977-01-4313205 Approved by the Government of Nepal, Ministry of Education, Science and Technology, Curriculum Development Centre (CDC), Sanothimi Bhaktapur

Oasis Radiant Computer Science, Book 8 4 Oasis Radiant Computer Science Book 8 Revised by Krishna K. Shrestha Layout Design: Zeeta Computer Service Pvt. Ltd. Ghantagrar, Kathmandu Publisher: Oasis Publication (P) Ltd. Anamnagar, Kathmandu Nepal Tel: 977-01-4313205 www.oasispublication.com.np Printed in Nepal © Publisher First edition : 2017 Second edition : 2018 Third revised edition : 2022 This book belongs to... Name : Mr./Miss .................................................................................. Class : ................ Section. .............. Roll No....... School : ................................................................................................ ..............................................................................................................

5 Oasis Radiant Computer Science, Book 8 Approved by Curriculum Development Centre CONTENTS Chapter Lesson Page No. 1 Fundamentals of Computer 7 2 History of Computer 15 3 Computer Generations 23 4 Types of Computer 31 5 Computer Software 41 6 Operating System 47 7 MS Word 2010 61 8 MS Excel 95 9 MS PowerPoint 126 10 Cyber Crime, Cyber Law and Computer Ethics 146 11 Information and Communication Technology 155 12 Computer Viruses and Security Measures 164 13 Webpage Designing Using HTML 172 14 Computer Network System 191 15 Number System 203 16 Computer Graphics 214 17 Programming Tools and Technique 238 18 Programming in QBASIC 249

Acknowledgement We are in the 21st century. This is the age of Information and Communication Technology (ICT). ICT has become an integral part of our daily life. It facilities the work of business people, academicians, students and professionals in banking and other sectors. Computer education has become a fundamental right of children. Children need the knowledge of computer, from the basic to advanced level, to cope with the changes happening now and unfolding in the future. The Curriculum Development Centre (CDC) of Nepal government has prescribed syllabi and course outlines for computer education in schools from primary to higher secondary level. Students, however, are deprived of quality computer education due to the lack of quality course books and limited access to the computer system in schools. To address this issue, I have developed a complete series of computer books, under the banner of Oasis Radiant Computer Science, from grade I to grade XII. I have devoted a lot of time and effort in the research and development of this book. It provides a comprehensive and balanced coverage of the CDC syllabus. This series was possible due to the comprehensive support of my colleagues, family members, students and teachers. I would like to acknowledge all who have directly or indirectly encouraged me to prepare this book in the series. Specially, my thanks go to the students and teachers of different schools for their regular interactions and inspirations I have had in preparing this book. In the same way, my thanks go to my parents Tek Nath and Chisa Maya Adhikary, family members Lachhima Adhikary, Jagan Adhikary, Sarashwati Adhikary and lovely kids Samridhi, Sampada, Prasamsha, Ballavi, Ragavi, Suyash and Suyasha Adhikary for their valuable contribution to prepare this book. I must also give due thanks to OASIS PUBLICATION family for their innovative help to prepare and publish this book. Finally, all the suggestions and comments are acknowledged. Thanking all, Author

Fundamentals of computer 1 Chapter 8 The concept of computer system 8 Basic terms used in computer 8 Characteristics of computer 8 Working principles of computer

Oasis Radiant Computer Science, Book 8 8 Approved by Curriculum Development Centre A computer is an electronic machine that processes data to generate information. In other words, computer is a data processor: it takes in raw data at one end, stores it until it’s ready to work on it, processes them according to the logic given with the input and gives the results as output at the other end. We can define a computer as an electronic device that accepts data and instructions as input and uses storage to hold and store data for processing then delivers the result to the user using output devices. Working principles of computer Imagine if a computer were a person. Suppose you have a friend who’s really good at math. She is so good that everyone she knows posts their math problems to her. Each morning, she goes to her letterbox and finds a pile of new math problems waiting for her attention. She piles them up on her desk until she gets around to looking at them. Each afternoon, she takes a letter off the top of the pile, studies the problem, works out the solution, and scribbles the answer on the back. She puts this in an envelope addressed to the person who sent her the original problem and sticks it in her out tray, ready to post. Then she moves to the next letter in the pile. You can see that your friend is working just like a computer. Her letterbox is her input; the pile on her desk is her memory; her brain is the processor that works out the solutions to the problems; and the out tray on her desk is her output. The Concept of Computer 1 Chapter

Approved by Curriculum Development Centre 9 Oasis Radiant Computer Science, Book 8 Once you understand that computers are about input, memory, processing, and output, all the junk on your desk makes a lot more sense: A computer works by combining input, storage, processing, and output. All the main parts of a computer system are involved in one of these four processes. ● Input: Data and instructions are the input of the computer. The input unit helps to provide data and instructions into the computer that it can process. Some popular input devices like mouse, keyboard, and scanners are used to capture the input from the user. ● Memory/storage: It is the main storage part of the computer. Computer holds the processing data and stores them according to the user’s requirements. Different types of memories are: hard disk, floppy disk, Compact Disk, Digital Versatile Disk, Random Access Memory and Read Only Memory, etc. All the inputs are held to process and store on the memory unit of the computer, ● Processing: Central Processing Unit is a main component of the computer system that processes data according to the instructions given to the computer. After accepting the data and instructions CPU processes them arithmetically and logically. It has a very high speed of data processing. ● Output: Output from the computer is the result after the processing. Basically a computer gives hard and soft outputs to the user. Visual outputs from the visual display unit are soft outputs. Hard outputs are the printed forms of the result using printers and plotters. Characteristics of computer Speed: We know computer can work very fast. It takes only a few seconds for calculations that we take hours to complete. You will be surprised to know that a 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 to the power -6 part of a second) or nanosecond (10 to the power -9 part of a second). From this you can imagine how fast your computer performs work. Accuracy: The degree of accuracy of computer is very high and every calculation is performed with the same accuracy. It is determined on the basis of design of computer. The errors in computer are due to human and inaccurate data.

Oasis Radiant Computer Science, Book 8 10 Approved by Curriculum Development Centre 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 this capability it overpowers human beings in routine type of work. Versatility: It means the capacity to perform completely different types of work. You may use your computer to prepare payroll slips. The next moment you may use it for inventory management or to prepare electric bills. Power of Remembering: Computer has the power of storing a large amount of information or data. Any information can be stored and recalled as long as you require it, for any numbers of years. It depends entirely upon you how much data you want to store in a computer and when to lose or retrieve these data. No IQ: Computer is a dumb machine and it cannot do any work without instruction from the user. It performs as per instructions at tremendous speed and with accuracy. It is you to decide what you want to do and in what sequence. So a computer cannot take its own decision as you can. No Feeling: It does not have feelings or emotion, taste, knowledge and experience. Thus it does not get tired even after long hours of work. It does not distinguish between users. Storage: The computer has an in-built memory where it can store a large amount of data. You can also store data in secondary storage devices such as floppies, which can be kept outside your computer and can be carried to other computers. Terms and terminologies Computer System Different interrelated components working together to perform a specific task is called a system. A computer system is the combination of different parts of the computer for data processing. It accepts the data, processes them and gives the result to the user. A computer system has four basic components: hardware, software, firmware and the human ware. These components are working together to form the computer system.

Approved by Curriculum Development Centre 11 Oasis Radiant Computer Science, Book 8 Hardware Physical parts of the computer which we can touch and feel are the hardware components of computer. We have different types of hardware: input hardware, processing and storage hardware and output hardware. Software Collections of programmes to perform certain tasks are called software. We have different types of software: system software, application software and utility software. Software gives life to the hardware structure of the computer. Firmware The micro programmes stored in the Read Only Memory (ROM) is called firmware. Firmware helps to control the overall structure of the computer and configure the setup of the computer system. Humanware The relationship of the computer with the human or user is called the humanware. A computer system will be a complete system only with the interventions of the user. Without the involvement of the human or user, a computer system is incomplete. Netware Derived from the two words NETwork and softWARE. NetWare is a network operating system. A Local-Area Network (LAN) operating system was developed by Novell Corporation. NetWare is a software product that runs on a variety of different types of LANs. Data Raw facts which have individual meaning are called data. They are quantities, characters and symbols. Data are the small units of information. A computer accepts different types of data for further processing to generate the information. Instructions All the commands given to the computer to perform a specified task are called instructions. A user should communicate with the computer system by using the

Oasis Radiant Computer Science, Book 8 12 Approved by Curriculum Development Centre commands. According to the instructions given to the computer, a computer system does the functions. Data processing It is the process that accepts data and instructions as input and processes them to generate some specified output. Data processing system accepts data as input and processes them logically and arithmetically to generate output. A computer system is the data processing system that accepts different types of input like number, alphabets and picture data and processes them to generate different outputs like reports. Information Programme Collections of the commands and statements to perform certain tasks are called programme. Computer programmers develop different types of software by collecting similar types of programmes. They use suitable programming for developing the software. Programming languages A communication medium is also called the language. Computer programming language is used to develop the software. Some languages are based on the user’s language and some are only meant for the machines. We can classify the programming languages into different generations. Programmers People who develop the computer programmes and software are called computer programmers. Programmers develop the programme according to the requirement of the users. Programmers use different types of programming languages to develop the programmes.

Approved by Curriculum Development Centre 13 Oasis Radiant Computer Science, Book 8 Key Points ● Computer is an electronic device that accepts data and instructions as input and uses storage to hold and store data for processing and delivers the result to the user using output devices. ● A computer works by combining input, storage, processing, and output. All the main parts of a computer system are involved in one of these four processes. ● Computer system is the combination of different parts of the computer for data processing. It accepts the data, processes them and gives the result to the user. ● We have different types of hardware: input hardware, processing and storage hardware and output hardware. ● We have different types of software: system software, application software and utility software. Software gives life to the hardware structure of the computer. ● Firmware helps to control the overall structure of the computer and configure the setup of the computer system. ● A computer system will be a complete system only with the intervention of the user. Without the involvement of the human or user computer system is incomplete. ● Netware is derived from the two words NETwork and softWARE. NetWare is a network operating system. ● Data are the small units of information. Computer accepts different types of data for further processing to generate the information. ● User should communicate with the computer system by using the commands. According to the instructions given to the computer, a computer system does its functions. ● Data processing system accepts data as input and processes them logically and arithmetically to generate output. ● Computer programmers develop different types of software by collecting similar types of programmes. ● A communication medium is also called a language. Computer programming language is used to develop the software. ● People who develop the computer programmes and software are called computer programmers.

Oasis Radiant Computer Science, Book 8 14 Approved by Curriculum Development Centre Exercise 1. State whether True or False. a. Processing converts raw facts into meaningful information. b. Printer is a processing device. c. Memory is the data and information placeholder. d. Computer works on the instructions given by user. e. Mouse is an input device. f. The micro programmes stored in the Read Only Memory (ROM) are called firmware. 2. Match the following: Group A Group B i. Data a. Input, Process, Output ii. Storage b. Plotter iii. Output c. CPU iv. IPO d. Raw facts v. Processing e. Hard disk 3. Answer the following questions: a. What is computer? b. Explain the working principle of computer. c. What is storage? d. What is input? List any 5 examples. e. What is output? Give any 4 examples. f. Define information. g. Write any 4 characteristics of computer. h. Define programming and programmer.

Approved by Curriculum Development Centre 15 Oasis Radiant Computer Science, Book 8 History of Computer 2 Chapter 8 The concept of counting 8 Early development of mechanical devices 8 Electromechanical devices 8 Electronic computers

Oasis Radiant Computer Science, Book 8 16 Approved by Curriculum Development Centre Primitive people did not have any fixed place to stay. They used to move from one place to another with their cattle. They did not need any record keeping and calculation. Sometimes they used fingers for counting. But for large numbers it was impossible to use fingers for counting and calculations. So in the ancient age, people used stones, pebbles and other objects for counting and record keeping. Hindu philosophers developed the number system 0 to 9. By using these numbers they derived other numbers for counting and record keeping. During this time, many devices were developed for counting and calculations. According to the technology and capabilities of the devices, the evolution of computer is divided into three eras. ● Early development of mechanical devices ● Electromechanical computers ● Electronic computers Early Development of Mechanical Devices Abacus Abacus was the first counting device, developed by Chinese and Egyptians around 600 BC. It gave the mathematical concepts and arithmetical operations. It consists of a rectangular box, divided into two parts separated by mid bar. Upper part is called heaven that consists of two beads and each bead equals to 5. Lower part is called earth that consists of five beads and each bead equals to 1. Napier’s Bones John Napier from Scotland invented the calculating device in 1614. It was popular as Napier’s bones. It was a clever multiplication tool based on the concept of logarithms. The Napier's Bones Abacus History of Computer 2 Chapter

Approved by Curriculum Development Centre 17 Oasis Radiant Computer Science, Book 8 bones are a set of vertical rectangular rods, each one divided in 10 squares. John Napier is also the inventor of the logarithms. Slide Rule The first slide rule was developed by British mathematician William Oughtred in 1620. It was based on the logarithmic scale invented by Scottish mathematician John Napier in 1614. It consists of two graduated scales, one of which slides upon the other. The scales are devised in a way to suit the alignment of one scale against the other. It makes it possible to obtain products, quotients or their function by inspection. It was the first analogue device used in computing. Pascaline Pascaline was invented by Blaise Pascal in 1642 AD. The young Pascal devised a mechanical calculator to help his father who was a tax collector. It had some wheels and gears rotating in complement to each other. It could add and subtract by the movement of wheels. Charles Babbage Charles Babbage was born in 1791 in Teignmouth UK. He was one of the creative thinkers in the field of computer science. He is considered as the father of computer science. He was also a famous mathematician. He built a machine that could perform difficult calculations accurately and quickly. Due to the lack of technology and devices, he could not complete his task but now a days all computers are based on his idea. He had devised the machine called difference engine and analytical engine on the basis of his principle. He had used the concept of binary digit in his machine. The idea of Babbage engine can be summarised below. ● Data and programme instructions are fed by suitable input devices ● Storage device is used to store data and instruction. Pascaline Calculator

Oasis Radiant Computer Science, Book 8 18 Approved by Curriculum Development Centre ● It could perform the processing. ● A suitable output device was used to display results. Lady Augusta Ada Ada was the daughter of great English poet Lord Byron and the follower of Charles Babbage. She suggested Babbage to use binary numbers in his device. She was the first person who developed a programme by using the binary number system, so she is considered to be the first computer programmer. Electromechanical Computers Some electromechanical devices were invented around the beginning of 19th century. They were based on the principle of electronic and mechanical processes, so they were called electromechanical devices. They were more advanced than the mechanical devices. They had all the features of modern computers. Popular electromechanical devices were Mark I, ABC, etc. Mark-I Howard H. Aiken (1900-1973), a Harvard engineer working with three engineers of IBM, constructed a large automatic digital computer based on IBM electromechanical parts in 1937. This machine is called Harvard Mark-1. It was also called IBM ASCC (Automatic Sequence Controlled Calculator). Mark-I computer is characterised by such features: ● 18,000 vacuum tubes were used. ● It consisted of 7 lakh 50 thousand parts. ● It was 51ft long, 8ft high and 3ft wide. Atanasoff-Berry Computer (ABC) The Atanasoff-Berry Computer was the electromechanical digital computer built in 1937-1942 at Iowa State University by John V. Atanasoff and Clifford Berry. Main features of this computer are: ● It used 18000 valves and other 45 valves

Approved by Curriculum Development Centre 19 Oasis Radiant Computer Science, Book 8 for internal logic and capacitors for storage of electrical charge. ● It introduced the ideas of binary arithmetic, regenerative memory and logic circuit. ● It used punch cards as secondary storage. Electronic Computers ENIAC (Electronic Numerical Integrator and Calculator) This electronic machine was designed by Dr. John W. Mauchly and Dr. J. Presper Eckert. It was completed in 1946. The features of ENIAC are given below. ● It was set up on 1,800 square feet of floor space. ● It was built from 18,000 vacuum tubes, and 70,000 resistors. ● Its power consuming capacity was 50,00,000 kilowatt. ● It was a very fast machine compared to the earlier electromechanical machines. ● It could add two numbers in 200 microseconds and multiply of two numbers in 2800 microseconds. EDVAC (Electronic Discrete Variable Automatic Computer) John Von Neumann was the doctorate in mathematics from the University of Budapest on set theory. Von Neumann designed the Electronic Discrete Variable Automatic Computer (EDVAC) with team of J.P. Eckert and J. W. Mauchly. He gave the concept of stored programme in computer. The key element to von Neumann architecture was the central processing unit, which allowed all computer functions to be coordinated through a single source. He was regarded as the “Father of stored programme”.

Oasis Radiant Computer Science, Book 8 20 Approved by Curriculum Development Centre EDSAC (Electronic Delay Storage Automatic Computer) It was designed by Maurice Wilkes at Cambridge University mathematical laboratory in 1947. The features of this computer are given below. ● It contained 3000 vacuum tubes and operated on 30KW. ● It used a mercury delay line storage system where the access time was one milliseconds. ● The time required for addition was 1500 microseconds and that for multiplication was 4000 microseconds. UNIVAC (Universal Automatic Computer) It was the first and most powerful computer commercially available in this generation. It was capable of processing numeric and alphanumeric data and based on principle of stored memory of John Von Neumann. It was used for business data processing. J.P. Eckert and J.W. Mauchly had developed it in 1951. It was the first computer manufactured for commercial use and general purpose digital computer. Key Points ● Abacus was the first counting device, developed by Chinese and Egyptians 2500 years ago. ● Napier's bones was very successful and was widely used in Europe until mid 1960's. ● The slide rule is an analogue device for performing mathematical computations. ● Charles Babbage was an English man who was one of the creative thinkers in the field of computer science. He is considered to be the father of computer science.

Approved by Curriculum Development Centre 21 Oasis Radiant Computer Science, Book 8 ● Charles Babbage was also a mathematician. ● Herman Hollerith developed punch card called electromechanical punch card or Hollerith’s tabulating machine or census machine. ● Atanasoff-Berry Computer was the electromechanical digital computer. ● ENIAC was a very fast machine compared to earlier electromechanical machines. ● ENIAC operated on punch card, which were the input/output devices with one multiplier, one divider/square rooter and twenty adders. ● ENIAC was built from 18,000 vacuum tubes, and 70,000 resistors. ● UNIVAC was the first and most powerful computer commercially available in this generation. ● John Von Neuman give the concept of stored programme in computer. Exercise 1. Answer the following questions. a. Who is known as the first programmer of the world? b. What are early mechanical devises? List any five early made devices. c. When was slide rule invented and who invented it? d. Who is the Father of Computer Science? e. Who was inventor of Pascaline? f. Write some features of Babbage engine. g. List any five electronic computers. h. Write down the features of Mark I. i. What are the contributions of Charles Babbage in the computer history? 2. Give the full forms of the following: a. ABC b. ENIAC c. UNIVAC d. EDSAC e. EDVAC 3. Fill in the blanks: a. …………………..is known as the father of computer science. b. Fill form of EDVAC is …………………… c. …………………. was developed by John Von Neumann. d. ABC was …………………..computer. e. Charles Babbage was also the ………………..

Oasis Radiant Computer Science, Book 8 22 Approved by Curriculum Development Centre f. ……………was first calculating device. g. ……………….part of Abacus is called heaven. h. ………………..part of Abacus is called earth. i. ……………….. developed Slide Rule. j. …………….. developed Pascaline. 4. State true or false: a. Heaven part of Abacus has the beads with value 5. b. William Oughtred developed Napier’s Bone. c. Napier’s Bone is related to logarithms. d. Charles Babbage developed Pascaline. e. Mark – I is the first electromechanical computer. f. ENIAC is mechanical device. g. ABC is electronic computer. h. Full form of IBM is International Business Machine. i. Lady Augusta Ada was the first computer programmer. j. EDVAC is also known as Abacus. 5. Write the technical terms of the following: a. The first mechanical calculating device invented by Chinese. b. The first programmer. c. A computer programming language named after Blaise Pascal. d. Father of Computer Science. 6. Class Activity: a. Compare between mechanical and electronic devices with some examples. b. Write some features of early computers. 7. Project Work: a. Collect different types of mechanical devices and paste their figure in your project copy. b. Make a list of mechanical, electromechanical and electronic computers. c. Explain the contributions of the following in development of computer i. Egyptians ii. John Napier iii. William Oughtred iv. Blasé Pascal v. John Von Neumann d. Prepare a project report about the history of computer with the help of Encyclopedia and Wikipedia and submit it to your subject teacher.

Approved by Curriculum Development Centre 23 Oasis Radiant Computer Science, Book 8 Computer Generations 3 Chapter 8 Introduction to generations of computer 8 The first generation of computer 8 The second generation of computer 8 The third generation of computer 8 The fourth generation of computer 8 The fifth generation of computer

Oasis Radiant Computer Science, Book 8 24 Approved by Curriculum Development Centre Technology is the most dynamic innovation and it has a great role for the evolution of computers. Evolution of computer started from the 16th century. The present day computer, however, has also undergone rapid changes during the last fifty years. They differ in terms of shape, size and the devices used in the computer. According to innovations and use of technology, the evolution of the computer can be divided into five distinct phases known as Generations of Computers. To restate, computer generations deal with the technological innovations and their uses in computer. Basically there are five generations of computer. ● First Generation Computer ● Second Generation Computer ● Third Generation Computer ● Fourth Generation Computer ● Fifth Generation Computer First Generation Computers First generation computers used Thermion valves called vacuum tubes. These computers were large in size and writing programmes on them was difficult. Features of First Generation Computers ● They used vacuum tubes as memory device. ● They were very large in size. ● They consumed a lot of electrical power. ● They were very slow. ● The operating speed was in terms of milliseconds. ● They used machine level programming language. ● Storage capacity was too small, only 1 to 4KB (kilobyte). ● They were used only for scientific and research purpose. Computer Generations 3 Chapter

Approved by Curriculum Development Centre 25 Oasis Radiant Computer Science, Book 8 Limitations of First Generation Computers First generation computers were the initial computers. They had limited capacity and speed. Main limitations of this generation were: ● Required large space for installation. ● The operating speed was quite slow. ● The programming capability was quite low. ● Power consumption was very high. ● Programme and data were stored in separate memories. ● Machine level programming language was used for programming. Some popular first generation computers were: ENIAC: It was the first electronic computer built in 1946 at University of Pennsylvania, USA by John Eckert and John Mauchy. EDSAC: It stands for Electronic Delay Storage Automatic Computer and was developed by M.V. Wilkes at Cambridge University in 1947. EDVAC: It stands for Electronic Discrete Variable Automatic Computer and was developed in 1950. The concept of storing data and instructions inside the computer was introduced here. UNIVAC-1: Ecker and Mauchly produced it in 1951 by Universal Accounting Computer setup. Second Generation Computers Around 1955 a device called transistor replaced the bulky electric tubes in the first generation computer. Transistors were smaller than electric tubes and had higher operating speed. Manufacturing cost was very low. Thus the size of the computer got reduced considerably.

Oasis Radiant Computer Science, Book 8 26 Approved by Curriculum Development Centre Features of Second Generation of Computers ● They used transistor as memory device since 1000 vacuum tubes were replaced by only one transistor. ● They were faster than first generation computers. ● They were smaller than the first generation computers. ● They consumed less electrical power than the first generation. ● The operating speed was in terms of Microseconds. ● They could understand high level languages. ● Input and output devices were much faster. ● Magnetic core memory was used as internal storage. ● Magnetic tapes were used as secondary storage media. The names of second generation computers are given below. 1. IBM 1401: Its size was small to medium and it was used for business applications. 2. IBM 1620: Its size was smaller as compared to the first generation computers and it ws mostly used for scientific purpose. Third Generation Computers The third generation computers were introduced in 1966. They used Integrated Circuits (ICs). These ICs are popularly known as Chips. A single IC has many transistors, registers and capacitors built on a single thin slice of silicon. Features of Third Generation Computers ● Integrated circuits were the main feature of the third generation computers. ● They were small, efficient and reliable. ● The operating speed was in terms of Nano seconds. ● Magnetic disks were used as secondary memory. ● Semiconductor memory was used as primary memory.

Approved by Curriculum Development Centre 27 Oasis Radiant Computer Science, Book 8 ● Input and output devices such as key board and monitors were added. ● They could understand a large number of high level languages. Some of the computers of the third generation were 1. IBM-360 2. ICL-1900 3. IBM-370 4 VAX-750 Fourth Generation Computers The present day computers that you see today are the fourth generation computers that started around 1974. It uses large scale Integrated Circuits (LSIC) built on a single silicon chip called microprocessors. Due to the development of microprocessor it is possible to place computer’s central processing unit (CPU) on a single chip. These computers are called microcomputers. Later very large scale Integrated Circuits (VLSIC) replaced LSICs. Features of Fourth Generation Computers ● The sizes of fourth generation computers were reduced to desktop or laptop computer. ● Use of large scale integration is the main characteristic of this generation. ● Magnetic and optical storage devices with capacity more than 100GB (giga byte) were used as secondary memory. ● The operating speed increased beyond picoseconds and MIPS (Million of instruction per second). ● 4GL (4th generation language) are also used. ● Multiprocessing and multiprogramming OS (Operating System) are used.

Oasis Radiant Computer Science, Book 8 28 Approved by Curriculum Development Centre Some of the computers of the fourth generation are: 1. 8086 2. 8088 3. 80286 Sx 4. 80386 Dx 5. 80386 Sx 6. Pentium I 7. Pentium II 8. Pentium III Fifth Generation Computers The computers having Artificial Intelligence (AI) and high processing capacity undergoing development from 1990 are said to be Fifth Generation Computers. ● They can perform large number of parallel processing. ● The speed is extremely high in fifth generation computers. ● Bio chips and Gallium Arsenide (GaAs) are used as memory devices. ● The concept of Artificial Intelligence has been introduced to allow the computer to take its own decision. It is still in developmental stage. ● Large uses of natural language processing and user friendly. Key Points ● First generation computers used thermion valves. These computers were large in size and writing programmes on them was difficult. ● Transistors are smaller than electric tubes and have higher operating speed. ● The invention of transistors marked the start of the second generation. ● In Second Generation computers, the instructions (programme) could be stored inside the computer's memory. ● High-level languages such as COBOL (Common Business-Oriented Language) and FORTRAN (Formula Translator) were used, and they are still used for some applications nowadays as a second generation language. ● Second generation computers used transistor as memory device since 1000 vacuum tubes were replaced by only one transistor. ● The third generation computers were introduced in 1966.

Approved by Curriculum Development Centre 29 Oasis Radiant Computer Science, Book 8 Exercise 1. Answer the following questions. a. What is computer generation? b. List out the different generations of computers. c. Write down the features of first generation computers. d. Mention the features of second generation computers. e. Explain some limitations of first generation computers. f. List some examples of first and second generation of computers. g. Write some features of fourth generation of computers. h. What are the fifth generation computers? Write down their features. i. List some features of third generation computers. j. Give some examples of third and fourth generation computers. 2. Write short notes on: a. Vacuum tube b. Transistor c. Integrated Circuit (IC) d. Artificial Intelligence (AI) 3. Differentiate between: a. First and fourth generations of computers b. Transistors and vacuum tubes c. Third and second generation computers d. Integrated Circuit and Large Scale of Integration e. Fifth generation and second generation computers ● The sizes of fourth generation computers were reduced to desk top or lap top computer. ● Magnetic and optical storage devices with capacity more than 100GB (giga byte) were used as secondary memory. ● Multiprocessing and multiprogramming OS are used by fourth generation of computers.

Oasis Radiant Computer Science, Book 8 30 Approved by Curriculum Development Centre 4. Give the full forms of the following: a. IC b. LSI c. VLSI d. ULSI e. GaAs 5. Fill in the blanks: a. ………………….. used vacuum tubes as memory components. b. Full form of IC is ………………….. c. Pentium brand computers are …………………..generation computers. d. Full form of VLSI is ………………….. e. Fifth generation computers have ………………..chip. 6. State true or false: a. First generation computes used IC as memory device. b. Second generation computers were faster than first generation computers. c. Third generation computers used Integrated Circuits. d. Very Large Scale Integration was used in third generation computers. e. Fifth generation computers used Bio-Chips as memory. 7. Class Activity and Project Work: a. Compare between different generations of computers in terms of memory system and electronic component. b. Describe the following: Vacuum tubes, Transistors, IC, and Bio-Chips with their features and figure.

Approved by Curriculum Development Centre 31 Oasis Radiant Computer Science, Book 8 Types of Computer 4 Chapter 8 Analogue, or analog, computer 8 Digital computer 8 Hybrid computer 8 Mini and microcomputer 8 Super computer

Oasis Radiant Computer Science, Book 8 32 Approved by Curriculum Development Centre Introduction Computers are popularly used in different areas to support our daily works. According to the nature of job and the applications you can use different types of computer. There are various types of computers available in the market. In broad approach, you can classify the computer into two types: Special purpose computers and General purpose computers. Special purpose computers are developed for particular applications like temperature recording, measurement of altitude etc. General purpose computers are the standard computers used for general application like word processing, spreadsheet, database application, internet access, programme development, etc. We can classify the computer into different types. Popular types are: - Analogue Computers - Digital Computers - Hybrid Computers - Microcomputers - Minicomputers - Mainframe Computers - Super Computers Analogue Computer The term analogue computer is derived from a Greek word Analog. An analogue computer is one that measures physical values such as temperature and pressure that fall along a continuous scale. They are general purpose computers and are designed for particular works. For example, speedometer, temperature recorder, telephone billing system, etc. Types of Computer 4 Chapter

Approved by Curriculum Development Centre 33 Oasis Radiant Computer Science, Book 8 Digital Computer General purpose computers which are developed for all types of users and general purposes and based on digits are called digital computers. A digital computer is one that directly counts numbers using digits. Digital computers are the most popular computers used for report generation, documentation, billing and other graphical work. All types of PC used today on different fields are digital microcomputers. Hybrid Computer Computers that use both analogue and digital data and processes are called hybrid computers. These computers work on digital as well as analogue processing. Qualities of analogue and digital computers are combined in these computers. These are used at Intensive Care Units of hospital, Jet planes and other data analysis terminals. Hybrid computers transfer the data from analogue to digital and digital to analogue. Comparison of Digital, Analogue and Hybrid Computers Analogue Computer Digital Computer Hybrid Computer Computer that uses analogue signal is called analogue computer. Computer that uses binary digits is called digital computer. Computer that uses both binary and analogue signals is called hybrid computer. Fast Slow Intermediate in speed Less accurate Accurate Intermediate in accuracy Noisy Less noisy Depends on computer

Oasis Radiant Computer Science, Book 8 34 Approved by Curriculum Development Centre Super Computer Computers which have a very high speed and storage capacity to perform several tasks in a fraction of second are super computers. These are multi-user, multiprocessing large computers with very high efficiency and storing capacity. Supercomputers are able to solve very difficult and complex problems with very high speed. Applications - used to forecast the weather and global climates - used in military research and defence systems - used in automobile, aircraft, and space craft designing - used in encrypting and decoding sensitive intelligence information Example: CRAY, CDC-205 Mainframe Computer Multi-user and powerful computers used in large business organisations, examination departments and industries, etc. to process data of complex nature are called mainframe computers. They use powerful processors for complex data processing. More than 100 users can use a mainframe at a time because it works on time sharing mode. Application - Government and civilian purposes - Bank account management - Air traffic control system - Industrial design Example IBM S/390, IBM S/709, ICL 39, CDC 6600 Super Computer Mainframe Computer

Approved by Curriculum Development Centre 35 Oasis Radiant Computer Science, Book 8 Minicomputer Minicomputers are larger and more powerful than microcomputers but are smaller and less powerful than mainframe computers. They are also multi-user computers and support more than dozens of people at a time. A minicomputer is costlier than a microcomputer. It is also used in universities and large business organisations to process complex data. It is also used in scientific research, instrumentation system, engineering analysis, and industrial process monitoring and control. Example PDP-11, VAX, etc. Microcomputer In 1976 the first Personal Computer Apple-1, was designed. In 1981 August, IBM introduced the IBM 5150 PC, in New York. Now-adays mostly used computers are microcomputers. It is called Home PC or personal computer (PC) because it is a single user computer. It supports many higher level languages, multimedia, graphics, 3D graphics and games. It is popular among students, professionals and home users due to its small size, low price, and low maintenance cost and easy operation method. Example IBM PCs, Apple Mac, IBM PS/2, etc.

Oasis Radiant Computer Science, Book 8 36 Approved by Curriculum Development Centre Types of Micro Computer Microcomputers are small, low-cost and single-user digital computers. They consist of CPU, input unit, output unit, storage unit and the software. Microcomputers include desktop computers, notebook computers or laptop, tablet computer, handheld computer, smart phones and netbook computer. ● Desktop Computer or Personal Computer (PC) is the most common type of microcomputer. It is a stand-alone machine that can be placed on the desk. Externally, it consists of three units—keyboard, monitor, and a system unit containing the CPU, memory, hard disk drive, etc. It is not very expensive and is suited to the needs of a single user at home, small business units, and organisations. Apple, Microsoft, HP, Dell and Lenovo are some of the PC manufacturers. ● Notebook Computers or Laptops resemble a notebook. They are portable and have all the features of a desktop computer. The advantage of the laptop is that it is small in size (can be put inside a briefcase), can be carried anywhere, has

Approved by Curriculum Development Centre 37 Oasis Radiant Computer Science, Book 8 a battery backup and has all the functionality of the desktop. Laptops can be placed on the lap while working (hence the name). Laptops are costlier than the desktop machines. ● Netbook These are smaller notebooks optimised for low weight and low cost, and are designed for accessing web-based applications. Starting with the earliest netbook in late 2007, they have gained significant popularity now. Netbooks deliver the performance needed to enjoy popular activities like streaming videos or music, emailing, web-surfing or instant messaging. The word netbook was created as a blend of Internet and notebook. ● Tablet Computer has features of the notebook computer but it can accept input from a stylus or a pen instead of the keyboard or mouse. It is a portable computer. Tablet computers are the new kind of PCs. ● Handheld Computer or Personal Digital Assistant (PDA) is a small computer that can be held on the top of the palm. It is small in size. Instead of the keyboard, PDA uses a pen or a stylus for input. PDAs do not have a disk drive. They have a limited memory and are less powerful. PDAs can be connected to the internet via a wireless connection. Casio and Apple are some of the manufacturers of PDA. Over the last few years, PDAs have merged into mobile phones to create smart phones. ● Smart Phones are cellular phones that function both as a phone and as a small PC. They may use a stylus or a pen, or may have a small keyboard. They can be connected to the internet wirelessly. They are used to access the electronicmail, download music, play games, etc. Blackberry, Apple, HTC, Nokia and LG are some of the manufacturers of smart phones. Key Points: ● An analogue computer is one that measures physical values such as temperature or pressure that fall along a continuous scale in temperature or pressure. ● A digital computer is one that directly counts numbers or digits that present numbers, letters, or other special symbols. ● The good qualities of analogue and digital computers are combined to make hybrid computers. ● Hybrid computers transfer the data from analogue to digital and digital to analogue.

Oasis Radiant Computer Science, Book 8 38 Approved by Curriculum Development Centre ● Multi-user, multiprocessor large computer of very high efficiency and storing capacity is called a supercomputer. ● Minicomputers are larger and more powerful than most microcomputers but are smaller and less powerful than most large mainframe computer systems. ● In 1976 the first Personal Computer - Apple-1, Apple Computer was designed. In 1981 August, IBM introduced the IBM 5150 PC, in New York. ● Micro computer supports many higher level languages, multimedia, graphics, 3D graphics and games. 1. Answer these questions. a. What are special purpose computers? b. What are general purpose computers? c. What are digital computers? d. Analogue computers are special purpose computers? Why? e. Write the features of mainframe computers. f. Write the application areas of mini computers. g. What are hybrid computers? h. Write short notes on microcomputer. i. Write some applications of super computer. 2. Write short notes on: a. Analogue computers b. Special purpose computers c. Minicomputers d. Mainframe computers e. Super computers 3. Differentiate between: a. Analogue and digital computers. b. Mini and mainframe computers. c. Special and general purpose computer. d. Micro and mini computer. e. Super and mainframe computer. Exercise

Approved by Curriculum Development Centre 39 Oasis Radiant Computer Science, Book 8 4. Fill in the blanks: a. __________ computer works with digital bits 0 and 1. b. Analogue computers use __________ signal continuous. c. Physical value can be measured by using __________ computers. d. __________ computer is applicable for networking system to make a server. e. Full form of IBM is __________. f. Full form of PC is __________. g. CDC 6600 computer is __________ computer. h. Cray 1 computer is __________ computer. i. PS/2 computers are __________ computers. j. Hybrid computers are the combination of ____ and ______ parts. 5. State True or False. a. Hybrid computers are analogue computers. b. Super computer is general purpose computer. c. Full form of PC is Private Computer. d. IBM compatible computers are micro computers. e. Mainframe computers have very high speed of processing and huge storage. 6. Project Work a. Collect some examples of analogue, digital and hybrid computers. b. Write the brand names and models of computers available in your computer lab.

Oasis Radiant Computer Science, Book 8 40 Approved by Curriculum Development Centre Computer Software 5 Chapter 8 Introduction to computer software 8 System software 8 Application software 8 Utility software

Approved by Curriculum Development Centre 41 Oasis Radiant Computer Science, Book 8 Introduction What is software? It is a collection of programme and other associated documents that helps to control, manage and integrate the components of computer system to perform a specific task. Computer system is nothing without the software. Hardware needs software, like a car needs a driver, to operate smoothly. These are complementary to each other. Programmes are the collections of data and instructions in a systematic order to perform some work. These programmes are organised and collected in a systematic order to tell the computer what to do and how to do it. For example, the software instructs the hardware what to display on the user's screen, what kinds of input to take from the user, and what kinds of output to generate. Types of Software In a broad sense, we can classify software into three types. 1. System software 2. Application software 3. Utility software System Software The software that helps to activate the computer system and provide operating environment for other application software is called system software. Its primary work is to control, integrate and manage Computer Software 5 Chapter

Oasis Radiant Computer Science, Book 8 42 Approved by Curriculum Development Centre the individual’s hardware components of the computer system. This software provides an operating and programming environment where programmer and user can create the application software for their day to day application. This can be explained under different groups: Operating System, Device Drivers and Language Translators. Operating System (OS) Software that helps to activate the computer system and provide the user with a common platform to operate on the computer system is called OS. It is the first layer of software loaded into computer memory at the time of booting. The main function of OS is to manage the disk access, files process, etc. Other software are loaded on the environment of OS. Windows Xp, Linux, MSDOS etc. are popular OS. Device Drivers As we discussed, system software helps to activate and recognise the computer hardware devices. Computer system requires a special software called device drivers. A device driver is a programme that controls a particular type of device that is attached to your computer. To work with all devices, we need these software. For example, to work with printers we have to install the driver software, then only the printer will work. Language Translator Computer is a digital device. It can work only on the digits, which are 0 and 1. All types of commands, data and instructions require to be converted into machine codes, which is the combination of 0’s and 1’s. Different types of programming

Approved by Curriculum Development Centre 43 Oasis Radiant Computer Science, Book 8 languages accept the data and instructions in a natural language like English. But computer cannot process such data and instructions in natural language. So they should be translated into machine code. To convert such natural languages into machine code we need the system called the language translator. According to the nature of application processing, we have three types of language translators. Compilers: Translator systems that compile the whole programme and translate it into machine code at a time are compilers. This translator translates the whole programme at a time and creates an object code then executes the code, e.g. C Program, Pascal, etc. Interpreters: These are translators that can convert the programme code, line by line, without looking at the entire programme at a go. They translate each statement or line at a time and then translate another line, e.g. BASIC. Assembler: An assembler is a programme that takes basic computer instructions and converts them into a pattern of bits that the computer's processor can use to perform its basic operations. A translator that can convert assembly level language into machine code is assembler. Application Software Application Software is developed for specific purpose, so we can define it as user’s purpose software. These software are developed using High Level Language in the form of a creative project work by the software industries. There are many types of application software available for user purposes: - Word Processing: MS Word, Word Perfect, Word Star - Spreadsheet: MS Excel, Lotus-123, Quattro - Database Management: MS Access, dBase-IV, Clippers, Oracle, OMNIS, Ingress, Integra, FoxPro, FoxBASE, SQL - Graphics and Presentation: MS Paint, MS PowerPoint, CorelDraw, Adobe

Oasis Radiant Computer Science, Book 8 44 Approved by Curriculum Development Centre PhotoShop, Adobe Illustrator - Animation: Macromedia Director, Macromedia Flash, Adobe Image Ready, Adobe Premiere, Adobe After Effect - Web Designing: Macromedia Dream Weaver, Microsoft FrontPage Express Types of Application Software Basically we have two types of application software. These are packaged and tailored software. Packaged Software: Packaged software is readymade, bug free, advanced and standard software for special works. All word processing, database management, graphics and representation, animation and web-designing software are packaged software. These software are equipped with all essential tools and technologies to enhance user productivity. Tailored Software: Tailored software is small software, developed in higher level language for specific small processes. These types of software are developed for certain specific purpose. Example: Software for Payroll tailored for a specific organisation, Software for specific Bank, Software for Railway Reservation, Hotel Reservation, etc. These software are developed for solving specific problems of specific users or organisations. So these are called customised software. Utility Software Special types of system software used to maximise the utility of the hardware devices and computer system are utility software. We can use this software for scanning the hard disk, repair and maintain the computer system and remove viruses from the computer. Popular utility software are scandisk, antivirus and other toolkits used to repair and maintain computer.

Approved by Curriculum Development Centre 45 Oasis Radiant Computer Science, Book 8 Key Points ● Instructions given to the computer system to perform some task is called command. ● Physical structure of computer system that we can touch and feel is called hardware. ● Set of instructions consisting of one or more programmes that control the operation of computer system is called software. ● System software is software that organises the system and activates it to provide working environment for other application programme. ● Hardware is the "heart" of a computer system and software is the "soul" of system. ● Application software is a complete self-contained packaged programme designed to perform standard work. ● Translator is the programme that converts high level data (user language data) into machine code (computer code). ● Device driver introduces the new hardware components with the computer system. ● Utility software manages the hardware system and tries to maximise the utility of device. ● Packaged software is large-scale software developed by software houses. These are used for standard applications such as in office management. ● Tailored software is customised software developed for customer's demand. Exercise 1. Answer the following questions. a. What is command? b. What is software? c. List the types of software. d. What is translator? e. Define the system software. f. What is package software? g. Why is tailored software is required?

Oasis Radiant Computer Science, Book 8 46 Approved by Curriculum Development Centre h. Why is translator required? i. List any ten software packages and programmes. j. Write the functions of utility software with example. 2. Write short notes on: a. Programme b. Device driver c. Compiler d. Word processor e. Spreadsheet f. Database g. Operating system h. Utility software i. Package software j. Command 3. Differentiate between: a. Hardware and Software b. Complier and Interpreter c. Device driver and Utility software d. Packaged and tailored software e. Command and programme 4. Give the full form of: a. OS b. MS Word c. BASIC d. COBOL e. MS Excel 5. Fill in the blanks. a. MSDOS is __________ software. b. A set of __________ is called software. c. __________ translates high level data into machine code. d. __________ introduces new devices with computer system. e. __________ are custom-made software developed to meet the customer's requirement. 6. State True or False. a. Hardware is controlled by the software. b. Antivirus software is language translator. c. Packaged software is custom-made software. d. Device driver introduces the new hardware to computer system. e. MSDOS is system software. 7. Project Work a. Collect any five examples of system software. b. Name any five antivirus software. c. Make a list of any ten application software. d. Make a list of system software, application software and utility software used in your computer lab.

Approved by Curriculum Development Centre 47 Oasis Radiant Computer Science, Book 8 Operating System 6 Chapter 8 Introduction to operating system 8 Types of operating system 8 Functions of operating system 8 MSDOS and Windows system

Oasis Radiant Computer Science, Book 8 48 Approved by Curriculum Development Centre An OS (Operating System) is a collection of system programmes that together control the operations of a computer system. It activates and recognises the hardware devices and provides the operating environment for other application software. It acts like the intermediary between a user and the computer hardware. It has major two objectives: The first is to activate the hardware devices and the other is to provide an interactive interface to the user and interpret commands so that it can communicate with the hardware. Types of Operating System We can divide OS into different types on the basis of: ● Mode of use ● User interface On the Basis of Mode of Use According to the mode of uses and number of users we can classify it into two types. Single User Operating System It is usable by single user, at a time. It supports only one program at a Operating System 6 Chapter

Approved by Curriculum Development Centre 49 Oasis Radiant Computer Science, Book 8 time. These are used on general PC and other handheld devices. MS-DOS, PCDOS, etc are single user OS. Multi-user Operating System OS that allows multiple users to access a computer system concurrently is multiuser OS. When more than one user is processing data at the same time using one CPU is called Multi-user System. In this system, each operator has a time slice to accomplish their process using the processor. Time Slice is small time allotted by operating system to each operator for utilisation of processor. Its value is very small, so each operator feels that processor is processing their job only. Mainframe and mini computers are designed to serve the needs of multiple users. Example UNIX, LINUX On the Basis of User Interface We know that OS is the common place where user and system communicate to each others. User interacts with OS through using two types of interface. These are character or command based user interface which is called CUI and graphical elements based interface called Graphical User Interface (GUI). Command or Character based User Interface (CUI) It is traditional user interface. At early time of computing, OS provided the interactive terminal where user could enter the commands to interpret. This was the only one common place to communicate between a program and its user and so on. Now a days also, we are using such interface. Popular OS having command Line Interface is MSDOS. Graphical User Interface (GUI) With the advancement of technology, computer system has become quicker and cheaper. Operating environment also changed. This led to the development of graphical user interface where users can interact with computer system using picture and graphs, rather than character or commands. It displays the

Oasis Radiant Computer Science, Book 8 50 Approved by Curriculum Development Centre icons, buttons, dialogue box, etc. and others on the screen. The user sends the instruction and data by moving a pointer on the screen selecting certain objects by pressing button on the mouse. Popular GUI is Microsoft Windows. Differentiate between GUI and CUI S.N. GUI CUI 1 It is based on graphical user interface mode and instructions are given using graphical components like menu bar, toolbar, etc. It is based on command user interface mode and instructions are given using characters. 2 It uses keyboard, mouse and other advance devices. It uses only keyboard and may not be compatible with other devices 4 It is easy to learn and operate. Eg. MS Windows. It is difficult to operate and learn. Eg. MSDOS MS-DOS Full form of MS-DOS is Microsoft Disk Operating System. It has three essential files and many command files. These essential files are: IO.SYS, MSDOS.SYS, and COMMAND.COM. These files are called system files of MS-DOS. Windows Operating System Microsoft Windows is a Graphical User Interface(GUI)based operating systems developed by Microsoft Corporation. It is user friendly. It has various icons. There are different versions of windows like Windows Xp, Windows 7, Windows 10, etc. Starting Windows Start the computer, windows will be automatically started. We will get the following components on the windows system.