Approved by the Curriculum Development Centre (CDC/Government of Nepal) Sanothimi, Bhaktapur, Nepal
Book-7 Author Ganesh Gautam
Editor Deepti Budhathoki
Published By
Kantipur Education Development Council Published By
Kantipur Education Development Council Maharajgunj, Chakrapath, Kathmandu, Nepal email:[email protected] www.kedcnepal.com Tel: 01-4720202 / 01-4720517
© Reserved with Publishers
First Edition : 2017 (2074 B.S) Revised Edition : 2020 (2077 B.S)
No part of this book may be reproduced or copied in any form or by any means (graphic, electronic or mechanical, including photocopying, recording, taping or information retrieval system) or reproduced on any disk, tape, perforated media or any other information storage device, etc., without the written permission of the publishers. Breach of this condition is liable for legal action.
Layout and Concept by: Swift Tech Design and Print Ratopul, Kathmandu, Nepal
Printed in Nepal Preface
Computer technology has revolutionized our life style. Today computers impact every facet of our life. It has made a significant impact in teaching and learning in our schools. Because of the significance of computers in today’s world, it is important to be computer literate. It helps one to be more productive and efficient. IT For Kids has been developed with an objective of providing and enriching the students of Primary, Middle and Senior school with the latest information on computer technology. It is aimed at enhancing computer related competencies for students. The purpose of this book is to introduce the fundamentals of computer to the students. The book deals with both the theoretical concepts and the practical. The salient features of this series are: a. The language and vocabulary used is simple and clear. b. Know More provides a topic for further research c. Research and Report includes knowledge or research-based questions that take the students beyond their classroom d. Wow! to ignite interest in the students and enhance their level of curiosity. e. Word Help provides a glossary of important terms at the end of each chapter. f. Points for Review has been given at the end of each chapter for a quick recapitulation of all the topics in that chapter. g. Each chapter has a set of exercises which will test their understanding of the topic. h. Discussion Question consists of extensive questions to assess the knowledge of the concepts learnt. i. Practical Zone provides hands-on exercises based on the concept taught While a lot of care has been taken in ensuring the preparation of a conceptually accurate and error free book, the room for improvement is forever present. The author would be thankful for any suggestions for improvement. Author Contents
1. Computer Technology 1 2. Developments of Computers 12 3. Generations of Computer 23 4. Classification of Computer 30 Revision 39 5. Hardware and Software 41 6. Computer Number System 56 7. Computer Networks and the Internet 66 8. Computer Viruses 81 Revision 88 9. Multimedia Concepts 90 10. ICT Tools Cyber Ethics 100 11. Operating System 108 12. Word Processing 119 Revision 138 13. Presentation Software 140 14. Spreadsheet Software 156 15. Graphics Software 181 16. Programming Techniques 207 17. QBASIC Programming 218 Revision 242 1 Computer Technology Chapter Chapter
Overview
Computers have become an important part of human’s daily life. Computer technology is used in almost every sector of everyday life, including shops, ticketing counters, educational institutions, laboratories, business agencies and even homes. Most multinational companies have computers and Internet for marketing, communicating and doing business from different parts of the world. The development of computer technology has enabled people to live life of great luxury. People can solve complicated scientific and engineering problems using high technology including sophisticated computer hardware and software.
Computer - A Machine The term computer is derived from the word “computare” which means to calculate. A computer is an electronic machine, operating under the control of instructions stored in its own memory, that can accept data (input) manipulate the data according to specified rules (process) produce results (output), and store the results for future use. Computer accepts input through input devices, processes them and then performs arithmetic and logical operations on in accordance with a program and produces information as output through the output devices.
IT For Kids - Book 7 1 Data and Information Data is a collection of unorganized facts, which can include words, numbers, images and sounds. Computer manipulate and process data to create information Information is the organized data that has meaning and is useful. Examples are reports, newsletters, a receipt, a picture, an invoice or a cheque. Data entered into a computer is called input. The processed result are called output. Thus, a computer process input to create output. A computer can also hold data and information for future use in an area called storage. This cycle of input, process, output and storage is called the information processing cycle.
Input Data Processing Information
The Input-Process-Output Concept A computer is an electronic device that (i) accepts data (ii) process data (iii) generates outputs and (iv) stores data. The concept of generating output information from the input data is also referred to as input-process-output concept.
Input - The accumulation of raw data and the sequential set of instructions is called input. The device that send input to a computer is called input device. Input devices include keyboard, pointing devices, handheld devices and audio input devices. Processing - The act of performing arithmetic and logical operations is called processing. A computer processes data in a device called the Central Processing Unit. It is the computing part of any digital computer system, generally composed of the main memory, control unit, and arithmetic-logic unit. Output - Any information that has been processed by and sent out from a computer or similar device is considered output. The device that is used to get information out of the computer in a form which the user can understand is called output device. Output devices include display screens, loudspeakers, and printers. Storage - Storage is the area where a computer stores data and information. Storage device is the storage space in computer where data is to be processed and instructions required for processing are stored. Hard drive, USB flash drive and optical disk are some of the popular output devices.
2 IT For Kids - Book 7 Features of a Computer All computers have certain common characteristics irrespective of their type and size. Computers are capable of performing complex activities and operation. They can be programmed to do complex, tedious and monotonous tasks. Computers have become so indispensable because of the following characteristics.
Speed Computer can do routine calculations at tremendous speed in fact with the speed of light. This speed allows one to do computations that would otherwise be impossible. Progress would be considerably slowed down without them. The speed of a computer at performing a single operation can be measured in terms of :
Know More
Measurement of speed of a Computer Millisecond A millisecond is one thousandth of a second. Microsecond A microsecond is one millionth of a second. Nanosecond A nanosecond is one billionth of a second and is a common measurement of read or write access time to random access memory (RAM). Picosecond A picosecond is one trillionth of a second, or one millionth of a microsecond.
Accuracy Computers can process large amounts of data and generate error-free results, provided the data is entered correctly. If incorrect data is entered, the resulting output will also be incorrect. This computing principle-known as garbage out (GIGO) points out the accuracy of a computer’s output depends on the accuracy the input.
Automatic Computers are quite capable of functioning automatically, once the process is given to the computer. They do not require any instruction from the operator at any stage of the process. Computers can be programmed to perform a series of complex tasks involving multiple programs. Computers will execute the programs in the correct sequence, provided they are programmed correctly.
IT For Kids - Book 7 3 Storage Capability Computers have tremendous data storage capacity that can be retrieved very efficiently. The storage capacity of a computer can be increased byusing secondary storage devices such as magnetic disks and tapes. The storing capacity of a computer is measured in terms of bytes, kilobytes, megabytes and gigabytes.
Reliable A computer has a high degree of reliability because it carries out calculation with high speed and accuracy. It does the calculation repeatedly without making mistakes. And its circuits have no mechanical parts to wear and tear like in other machines.
Diligent Unlike human being, a computer is free from monotony, tiredness and lack of concentration. It can continuously work for hours, without creating any errors and without grumbling. Hence, computer store over human being in doing routine type jobs, which require great accuracy. If ten million calculations have to be performed, a computer will perform the ten millionth calculation with exactly the same accuracy and speed as the first one.
Versatile Computers can perform repetitive jobs efficiently. They can love labour problems or do hazardous jobs in a hostile environment. They can work in the areas where the human brain can err, for instance, observing the motion of very fast-moving articles. Also, they can work with different types of data and information like graphic, audio-visual characters etc.
Communications Most computers today have the capability of communicating with other computers. Computer with this capability can share any of the four information processing cycle operations -input. process, output and storage with another computer. For example, two computers connected by a communication device such as a modem can share stored data, instructions and information. When two or more computers are connected together via communications media and devices, they comprise a network.
4 IT For Kids - Book 7 Limitations of a Computer Computer is one of the most powerful tools ever developed. It is constantly being updated to make our lives better. It has many useful advantages however, it does possess some limitations. 1. A computer lacks in decision-making power. Computers cannot decide on their own. Computers are to be instructed at every step. If an unanticipated situation arises, computers will either produce erroneous results or abandon the task altogether. They do not have the potential to work out an alternate solution. 2. Computers cannot express their ideas. 3. Computers cannot think and they cannot do any job unless they are first programmed with specific instructions for same. They work as per stored instructions.
Basic Applications of a Computer Computers play an important role in man’s life. People are becoming more dependent on computer. Many products used in everyday life now incorporate computer systems: programmable, computer-controlled VCRs in the living room, programmable microwave ovens in the kitchen, programmable thermostats to control heating and cooling systems-the list seems endless. This section will give a brief idea of the impact of computer usage on various sectors of our society.
Computer for Small Business Computers play an important role in helping small business users manage their resource effectively. A small business, sometimes called a small office/home office (SOHO) such as an accounting firm, travel agency of florist usually has less than fifty employees. Small business often provide a desktop personal computer for some or all their employees. Many individuals also will have handled computers, specially web enabled PADs to manage appointments and contact information.
Computer for Mobile users As business expand to serve customers across the country and around the world, more and more people find themselves travelling to and from a main office to conduct business. Such users who needed to use a computer while on the road are examples of those with mobile computing needs. Mobile users often have laptop computers, handled computers, smart phones and other web enabled devices so that they can work while on the road.
IT For Kids - Book 7 5 Computer for Large business A large business can have hundreds or thousands of employee in office across a region,the country or the world. The company may have an equally large number of computers, all of which are connected in a network. This network is a local area network or a wide area network depending on the size of the company enables communication between employees at all locations. Employees in a large business often use handled computers. Many models of computers allow you to transfer data from a desktop computer to the handled so that you can have important information at your fingertips while attending meetings.
Computer at Schools Computers have become increasingly important in education. Different subjects are thought with the help of computers. Topic and exercise of mathematics, English and other subject can be done with their help. Imparting education through computer is very helpful for small kids because they can learn alphabets, numbers, word formation and number formation. Teachers can use computers to organize and prepare course materials. Computers are also helpful in other activities of school like preparing results, making time-table and collecting fee.
Computers at Hospital Computers have played a very important role in the growth and improvement of health care It is used in hospitals in keeping records of patients’ case histories, the symptoms of rare and common diseases and their corresponding medication, monitoring heart- beat pulse, blood-pressure and other such vital human features through computerised devices such as ECG Monitors and Computer Axial Tomography (CAT) scanner. They are also used to monitor the availability of beds, location of doctors and patients in large hospitals, calculation of hospital staff payrolls and patient’s medical fees.
6 IT For Kids - Book 7 Computer at Banks Computers have revolutionized accounting and bookkeeping, and banks. Modern banks use computers for storing financial information and processing transactions. Banking tellers also use computers to access customer data quickly. Customers often use computers for online banking. These banks have lower operating costs, and many are able to provide lower fees for their customers. Credit card companies allow customers to access information and process transactions online.
Computers in Entertainment Today, computers are used in many sources of entertainment. This has helped people to access entertainment in an easier way. Movies Computer photo and video editing and animation programs are one of the sources behind most movies. These programs made possible for the film industries to make those special effects that we love. Movies and TV series on the Internet are use of computers in entertainment.
Computers in Business Almost every business uses computers to complete daily tasks. In business, computers are used for communicating with clients and employees and researching and storing information. They are used for data processing, which includes tasks such as word processing, analysing data, entering records, payroll processing, personnel record keeping and inventory management.
IT For Kids - Book 7 7 Computer An electronic device that accepts input, performs calculations, and produces the required results. Data Collection of unarranged facts and figures that need to be processed to give them a meaningful information. GIGO ( Garbage In Garbage Out ) - The idea that if the data put into a computer or program is not good, the result that comes back will not be worth much.
Word Help Word Input The accumulation of raw data and the sequential set of instructions. Processing The act of performing arithmetic and logical operations. Storage The area where a computer stores data and information.
1. Computer technology is used in almost every sector of everyday life, including shops, ticketing counters, educational institutions, laboratories, business agencies and even homes. 2. A computer is an electronic machine, operating under the control of instructions stored in its own memory, that can accept data (input) manipulate the data according to specified rules (process) produce results (output), and store the results for future use. 3. Data is a collection of unorganized facts, which can include words, numbers, images and sounds. 4. A device that feeds data into a computer, such as a keyboard or mouse, is called an input device. 5. The act of performing arithmetic and logical operations is called processing. 6. The device that is used to get information out of the computer in a form which the user can understand is called output device. 7. Any information that has been processed by and sent out from a Points for Review Points computer or similar device is considered output. 8. A computer has a high degree of reliability because it carries out calculation with high speed and accuracy. 9. Computers can continuously work for hours, without creating any errors and without grumbling.
8 IT For Kids - Book 7 Chapter Review
Key Term Quiz
Fill in the blanks. a. A______is an electronic machine, operating under the control of instructions stored in its own memory, that can accept data (input) manipulate the data according to specified rules (process) produce results (output), and store the results for future use. b. ______is a collection of unorganized facts, which can include words, numbers, images and sounds. c. The accumulation of raw data and the sequential set of instructions is called ______. d. A ______is one millionth of a second. e. A computer has a high degree of ______because it carries out calculation with high speed and accuracy.
True or False
State whether the following statements are true or false. a. People can solve complicated scientific and engineering problems using high technology including sophisticated computer hardware and software. b. Information is the organized data that has meaning and is useful. c. A computer is an electronic device that (i) accepts data (ii) process data (iii) generates outputs and (iv) stores data. d. A picosecond is one thousandth of a second. e. Computers express their own ideas.
Technical Terms
Write the technical term for the following statements. a. A collection of unorganized facts, which can include words, numbers, images and sounds. b. The act of performing arithmetic and logical operations. c. The device that is used to get information out of the computer in a form which the user can understand. d. The device in computer where data is to be processed and instructions required for processing are stored. IT For Kids - Book 7 9 Matching Match the following. GIGO Collection of unarranged facts and figures that need to be processed to give them a meaningful information. Data The idea that if the data put into a computer or program is not good, the result that comes back will not be worth much. Processing The accumulation of raw data and the sequential set of instructions. Storage The act of performing arithmetic and logical operations. Input The area where a computer stores data and information.
Multiple Choice
Circle the word or phrase that best completes each statement. a. The accumulation of raw data and the sequential set of instructions is called______. i. input ii. output iii. storage iv. All of the above b. ______is the computing part of any digital computer system, generally composed of the main memory, control unit, and arithmetic-logic unit. i. RAM ii. ROM iii. CPU iv. All of the above c. A______is one millionth of a second. i. Millisecond ii. Microsecond iii. Picosecond iv. All of the above d. The idea that if the data put into a computer or program is not good, the result that comes back will not be worth much. i. GIGO ii. FIFO iii. LIPO iv. All of the above
10 IT For Kids - Book 7 Review Questions Answer the following questions. a. Computer is an electronic machine, that is used for data processing to produce meaningful information. Explain this statement. b. Differentiate between data and information. c. Discuss the main characteristics of a computer, which have made them so versatile and popular? d. Define the following terms: i. Millisecond ii. Picosecond iii. GIGO e. What are the limitations of computers? f. Explain the role of computers in small business. g. What is the role of computers in hospitals?
Discussion Question As directed by your instructor, discuss the following questions in class or groups. Explain the benefits of computer literacy in the modern society.
Word Power
Read the description and name it. a. A collection of unorganized facts, which can include words, numbers, images and sounds. b. The act of performing arithmetic and logical operations. c. The area where a computer stores data and information. d. One billionth of a second.
IT For Kids - Book 7 11 2 Developments of Computers Chapter Chapter
Overview
People lived on the earth for centuries without keeping records, but as social organizations such as tribes began to form, record keeping became necessary. The earliest computing device undoubtedly consisted of the five fingers of each hand. Since there are ten discrete fingers available for counting, both digital computation and the decimal system have enjoyed a huge popularity throughout the past. However, it became difficult for the early men to remember more facts using fingers and were gradually replaced by the use of sticks, marks onthe earth, scratches and symbols on the stones and knots on the ropes. These tools had the added advantage of storing easily the intermediate results for later use but the computing speed was slow. This necessitated the development of new machines for better and faster computation.
Abacus Abacus is the first mechanical calculating device invented by the Chinese 3000 years ago. It consists of wooden frame having parallel wires with beads strung on them. It has two regions-heaven and earth separated by mid- bar. There are two beads in the heaven which has the value of five and five beads on the earth has the value of one. Calculation were done by sliding the beads towards the mid-bar.
12 IT For Kids - Book 7 Napier’s Logs and ‘Bones’ John Napier was a Mathematician from Scotland. He invented the system of Logarithm in 1614 which greatly assisted in arithmetic calculations. He also invented a tool called Napier’s Bones in 1617, which were multiplication tables inscribed on strips of wood or bone. The bones are an aid for multiplication and division. Even square roots and powers could be done. It consisted of a set of 11 rods. Each bone contains a multiplication table of a number from 0 to 9.
Slide Rule William Oughtred, an English Mathematician invented Slide Rule in 1620. Slide Rule is a calculating device that used the principle of logarithm. It has two movable marked ruler kept side by side, one of which slide over the other. With the proper alignment of the two rulers, one could easily multiply and divide.
Pascaline Blaise Pascal, a French Mathematician built the first mechanical digital calculator called Pascaline in 1642. Pascal invented this device at the age of 18 to assist his father in tax calculation. The machine used gears, dials and wheels. Pascal’s invention utilized a train of 8 movable dials or cogs to add sums of up to 8 digits. As one dial turned 10 notches or a complete revolution, it mechanically turned the next dial. The disadvantage of Pascal’s invention was its limitations to addition and subtraction, while multiplication and division operations were implemented by performing a series of additions or subtractions.
IT For Kids - Book 7 13 Leibnitz’s Calculator A German Mathematician, Gottfried Wilhelm Von Leibnitz improved the Pascaline by creating a machine called Stepped Reckoner in 1694 that could add, subtract, multiply, divide and even evaluate square roots by series of stepped additions. The centerpiece of the machine was its stepped-drum gear design. Leibnitz also strongly advocated the use of the binary number system, which is fundamental to the operation of modern computers.
Jacquard’s Loom In 1801, a French silk weaver called Joseph- Marie Jacquard designed an automated loom that used punched cards as a pattern to weave intricate patterns. The punched cards (with holes or without holes) were secured tightly alongside each other in a sequential manner. These then passed over the loom-mechanism which detected the absence of hole leading to the wrap thread being raised and the presence of hole leading to the wrap thread not being raised.
Difference Engine Charles Babbage was a professor of mathematics at Cambridge University in England. He designed an automatic mechanical calculating machine, called a Difference Engine in 1823. Babbage’s Difference Engine was based on a complex system of cogs and levers, powered by steam. The machine was supposed to perform calculations and print the results automatically. The project could not be completed due to lack of funds.
14 IT For Kids - Book 7 Analytical Engine Charles Babbage, later devised the Analytical Engine in 1833. This machine which was capable of calculating up to 20 decimals at about 60 additions per minute. The machine was supposed to operate automatically, by steam power, and required only one person. This machine has following five units: 1. An input device 2. A storage facility to hold numbers for processing 3. A processor or number calculator (Mill) 4. A control unit to direct tasks to be performed 5. An output device This machine too could not be built due of lack of finance and inadequate technology at that time. However, he provided the basic idea of computers and hence he is regarded as “the father of modern technology”.
Lady Augusta Ada Lovelace Lady Ada Lovelace was the daughter of the illustrious English poet, Lord Byron. She was a splendid Mathematician and one of the few people who fully understood Babbage’s vision, created a program for the Analytical Engine. She used binary number system for programs and data to be fed into the Analytical Engine on punched cards. This was the first time the concept of computer programming was suggested. She is considered the first computer programmer. A programming language developed by the U.S. Department of Defence was named “ADA” in her honour in 1979. Hollerith’s Tabulating Machine Herman Hollerith was an American census statistician who worked for the U.S.Census Bureau. His first task was to find a faster way to compute the U.S.census. The previous census in 1880 had taken nearly seven and half years to finish the total counting while the next census was due in 1890. Herman Hollerith devised a Tabulating Machine in 1887 that used punched cards to store and tabulate census data. In using this new method for the 1890 census, the counting was completed within just six weeks and that too for a larger population. Hollerith Tabulating System was the first to make practical use of the punched card in data processing. His machine became the nucleus of today’s computing industry. His ideas were further developed and Hollerith established the Tabulating Machine Company in 1896 to manufacture his inventions. The company grew and prospered. This company later merged with other companies to form the giant International Business Machine (IBM) Corporation. IBM is the largest manufacturer of computers in the world.
IT For Kids - Book 7 15 Atanasoff Berry Computer The Atanasoff Berry Computer, later named the ABC, was built at Iowa State University from 1939-1942 by physics professor Dr. John Vincent Atanasoff and his graduate student, Clifford Berry in 1937-38. This was the first machine to calculate using vacuum tubes. It was designed to solve systems of linear algebraic equations and was capable of solving systems upto 23 unknown variables.
Harvard Mark-I Mark-I was the first automatic electromechanical computer. It was designed by Howard Aiken in 1937. The Mark-I was completed in 1944. It was constructed out of switches, relays, rotating shafts and clutches. This machine was 50 ft long, 8 ft tall and 3 ft wide having 18000 vacuum tubes and 7 lakhs 50 thousand parts, and weighed approximately 32 tons. This machine used instructions stored in paper tapes and punched cards. This machine was based on numbers that were 23 digits wide. Mark-I could add or subtract two of these numbers in three-tenths of a second, multiply them in four seconds and divide them in ten seconds. It was also known as the IBM Automatic Sequence Controlled Calculator (ASCC).
Electronic Numerical Integrator and Calculator (ENIAC) ENIAC (Electronic Numerical Integrator and Calculator) was the first electronic general-purpose computer invented by John Mauchly and J.P.Eckert in 1946 at the Moore school of Electrical Engineering of University of Pennsylvania. It was 10 feet tall, occupied 1,000 square feet of floor-space, weighed approximately 30 tons, and used more than 70,000 resistors, 10,000 capacitors, 60,000 switches, and 18,000 vacuum tubes.
Know More
The final machine required 150 kilowatts of power, which was enough to light a small town. ENIAC used a word of 10 decimal digits instead of binary digits. It could perform many complex arithmetic operations in less than a second.
16 IT For Kids - Book 7 Electronic Discrete Variable Automatic Computer (EDVAC) EDVAC (Electronic Discrete Variable Automatic Computer) was one of the earliest electronic computers. It was binary rather than decimal, and was designed to be a stored- program computer. It was invented by John Mauchly and J. P. Eckert in August 1944. The computer had almost 6,000 vacuum tubes and 12,000 diodes and consumed 56 KW of power. It covered 490 ft of floor space and weighed 8.7 tons. The computer had automation addition, subtraction, multiplication, programmed division and automatic checking with an ultra sonic serial memory.
Electronic Delay Storage Automatic Calculator (EDSAC) EDSAC (Electronic Delay Storage Automatic Calculator) was the first operational stored-program computer. John Von Neuman developed the stored program concept in 1945. This computer was developed on his idea of stored concept. It was invented by Maurice Wilkes at Cambridge University, England, in May 1949. EDSAC was made up of 3,000 vacuum tubes and used 30 kilowatts of electric power. The computer contained mercury delay lines for memory. Standing six feet tall and in three long racks were the control and arithmetic units. Programs were input using paper tape and output results were printed on a teletype page printer.
Universal Automatic Computer-I (UNIVAC-I) UNIVAC-I (Universal Automatic Computer-I ) was produced by Universal Accounting Company set up by John Mauchly and J.P. Eckert. It was the first general-purpose electronic digital computer designed for commercial use. It was also based on the EDVAC design. The UNIVAC-I was started in 1946 and completed in 1951. It was used in Census Bureau in early 1951 for use in census taking.
IT For Kids - Book 7 17 Apple-I Apple I computer was build by Steve Jobs and Steve Wozniak. They established Apple Computer Company on the 1st April 1976. It was less powerful and less expensive. It was demonstrated in July 1976 at the Homebrew Computer Club in Palo Alto, California.
IBM-PC IBM introduced its first personal computer, the IBM PC, in 1981. This computer was based on the 8088 microprocessor made by Intel Corporation and the MS- DOS operating system made by Microsoft Corporation. It had 16 KB of memory, a keyboard, a monitor, and one or two 5.25 inch floppy drives.
History of Computer in Nepal Computer was introduced in Nepal in the year 1972. It was introduced by His Majesty’s government for the population census of 1972(2028 B.S.) This was the second generation computer of IBM company called IBM 1401. The government had paid Rs 1,25,000 per month as rent for this computer. IBM 1401 took 1 year, 7 months and 15 days to process 1 crore and 12.5 lakhs population. Later, this computer was purchased by the government for further data processing in Bureau of Statistics. Later in 1975 (2031 BS) Yantrik Sarinikaran Kendra (Electronic Data Processing Centre) was established which was later called as National Computer Centre (NCC). Again for the population census of 2038 BS ICL 2950/10 computer having 64 terminals was brought in Nepal by the aid of UNDP. In 2039 B.S., microcomputers such as Apple, Vector, Sins, etc were imported by private companies and individuals. Many private companies like Computer Consultancy (CC), Management Information Processing System (MIPS), Data System International (DSI), etc were established. Such private companies started selling computers and training people in order to produce manpower in Nepal itself. Nowadays, computers with faster processing and larger storage are found cheaply in Nepalese market. Students are given computer education from school level. At present Computer Association of Nepal (CAN) is the governing body of Nepal.
18 IT For Kids - Book 7 Chinese Abacus The first calculating device invented by the Chinese in 3000 BC. Slide Rule An analog device with two movable marked ruler kept side by side, one of which slide over the other. Jacquard’s Loom The earliest programmable loom that used punched cards as a pattern to weave intricate patterns.
Word Help Word ENIAC The first electronic general-purpose computer invented by John Mauchly and J.P.Eckert in 1946. UNIVAC-I The first general-purpose electronic digital computer designed for commercial use.
1. Abacus is the first mechanical calculating device invented by the Chinese 3000 years ago. 2. William Oughtred, an English mathematician and clergyman constructed slide rule in 1620. 3. The French mathematician and philosopher, Blaise Pascal is credited for building the first mechanical calculating device called Pascaline in 1642. 4. A German mathematician and philosopher, Gottfried Wilhem von Leibniz improved the Pascaline by creating a machine called Stepped Reckoner in 1694. 5. In 1801, a French silk weaver called Joseph-Marie Jacquard designed an automated loom that used punched cards as a pattern to weave intricate patterns. 6. Babbage invented a “difference engine”, which was a device for producing mathematical tables. His “analytical engine” introduced Points for Review Points ideas that were later used in electronic computers. 7. Herman Hollerith, an American census statistician, devised the first “Tabulating Machine” in 1887. 8. Mark-I was the first full-sized digital computer, developed in 1944 by Howard Aiken at Harvard University.
IT For Kids - Book 7 19 Chapter Review
Key Term Quiz
Answer the following questions by filling in the blanks(s). a. ______consists of wooden frame having parallel wires with beads strung on them. b. ______developed the system of Logarithm in 1614 which greatly assisted in Arithmetic calculations. c. ______was a calculating device invented by William Oughtred, that used the principle of Logarithm. d. In ______, a French silk weaver called Joseph-Marie Jacquard designed an automated loom that used punched cards as a pattern to weave intricate patterns. e. ENIAC (Electronic Numerical Integrator and Calculator) was the first electronic general-purpose computer invented by ______and ______in 1946.
True or False
State whether the following statements are true or false. a. Abacus is a mechanical device used to assist a person in performing mathematical calculations. b. John Napier is an English Mathematician invented Slide Rule in 1620. c. Charles Babbage, an American census statistician, developed a mechanical tabulating machine in 1887 AD. d. EDVAC used 18000 vacuum tubes to process data. e. EDSAC (Electronic Delay Storage Automatic Calculator) was the first operational stored-program computer. f. UNIVAC-I was used in Census Bureau in early 1951 for use in census taking.
Technical Terms Give the full form of the following abbreviations. a. ABC b. ENIAC c. EDSAC d. UNIVAC e. EDVAC f. ASCC
20 IT For Kids - Book 7 Matching Match the following. Mark-I The first computer designed for commercial use. ABC The first automatic electromechanical computer. ENIAC The first electronic general-purpose computer. EDSAC The first digital computer. UNIVAC-I The first operational stored-program computer.
Multiple Choice
Circle the word or phrase that best completes each statement. a. Blaise Pascal, a French Mathematician built the first mechanical digital calculator called______in 1642. i. Napier’s bones ii. Pascaline iii. Slide Rule iv. All of the above b. In 1801, a French silk weaver called Joseph-Marie Jacquard designed an ______that used punched cards as a pattern to weave intricate patterns. i. Automated loom ii. Difference Engine iii. Analytical Engine iv. All of the above c. In______, the US Defence Department named a programming language ADA in her honour. i. 1979 ii. 1980 iii. 1981 iv. All of the above d. ______was the first electronic general-purpose computer invented by John Mauchly and J.P.Eckert in 1946 i. ENIAC ii. EDVAC iii. UNIVAC-I iv. All of the above e. Computer was introduced in Nepal in the year______. i. 1972 ii. 1973 iii. 1974 iv. All of the above
IT For Kids - Book 7 21 Review Questions Answer the following. a. Explain in brief how the calculations were done in the ancient period. b. Which was the first mechanical device invented by the Chinese? How were the calculations done in this device? c. Explain in short about Napier’s Bones. d. Who invented Slide Rule? On what principle does it work? e. Who is the first female programmer in the history of computer? f. Write in short about the Charles Babbage’s Analytical Engine? g. What did Joseph Marie Jacquard do? h. What did Herman Hollerith invent? What is the use of this machine? i. Name the first automatic electromechanical computer? Who invented it?
Discussion Question
As directed by your instructor, discuss the following questions in class or groups. Name the first general purpose electronic digital computer designed for commercial use? List any two features of this computer.
Write date of invention and name of the inventor for the following machines: a. Napier’s Logs and Bones b. Pascaline c. Jacquard’s loom d. Analytical Engine e. EDSAC f. UNIVAC
22 IT For Kids - Book 7 3 Generations of Computer Chapter Chapter
Overview
Computers are such an integral part of our everyday life. Now most people use them and they have added it to life totally for granted. The history of the computer goes back several decades however and there are five definable generations of computers. The term ‘generation of computer’ refers to the major development in electronic data processing over a period of time. Each generation is defined by a significant technological development that changes fundamentally how computers operate-leading to more compact, less expensive, but more powerful, efficient and robust machines.
First Generations Computers The first generation computers were developed between 1946 to 1958. The development of vacuum tubes signaled the beginning of the first generation. Vacuum tube was developed by Lee DeForest in 1908. The vacuum tubes consumed great amounts of electrical energy and the tubes heated quickly, and therefore caused many problems concerning temperature control. Also the tubes burnt out often, and had to be constantly replaced.
Know More
Vacuum tube was developed by Lee De Forest in 1908.
IT For Kids - Book 7 23 The features of first generation computers were: a. These machines used electronic switches in the form of vacuum tubes. b. Human operators had to set switches before a program could run. c. They were very big in size and occupied a very large space. d. The operating speed was measured in milliseconds. e. The power consumption was very high and generated much heat. f. These computers had low level of accuracy and reliability. g. They were mainly used in commercial and scientific applications. The examples of the first generation computers were ENIAC, EDVAC, EDSAC, UNIVAC-I, and IBM 650.
Second Generations Computers The second generation computers were developed between 1959 to 1964. The invention of the transistor by three scientists of Bell Telephone Laboratories in 1947 greatly changed the computer’s development. The three Bell Lab scientists’ are John Bardeen, Walter Brattain, and William Shockley. Transistors were made of a semiconducting material and controlled the flow of electricity through the circuits. They also allowed computers to become smaller, faster and more powerful at the same time. The features of this generations were : a. Transistors were used instead of vacuum tubes. b. They were less expensive, smaller in size than the first generation computers. c. They required less electricity and emitted less heat than vacuum tubes. d. They were more reliable and accurate than first generation computers. e. Their speed of operation was measured in microseconds. f. Punched cards and magnetic tape were used for input while punched cards and paper constitute the output. g. High level languages were developed. The examples of the second generations were IBM 1620, IBM 1401, Control Data 3600, 400 series and IBM 7000 series.
24 IT For Kids - Book 7 Third Generations Computers The third generation computers were developed during 1965-1974. Third-generation computers used Integrated Circuits. Jack Kilby, an engineer with Texas Instruments, developed the Integrated Circuit (IC) in 1958. Integrated Circuit is a collection of electronic circuit components miniaturized and built onto a single piece of silicon chip. A new program, an operating system was also introduced for automatic processing and multiprogramming. The features of third computer generations were The features of this generations were : a. Transistors were replaced by Integrated Circuits in their electronic ciruitry. b. Monitors and keyboards were introduced for input and output of data. c. Magnetic disks were used for auxiliary memory. d. The size of the computer became much smaller. e. The speed of operation was measured in nanoseconds. f. They had a larger storage capacity. g. They were reliable and better in performance. The examples of third generation computers were IBM system/360, Honeywell 200 series, National Cash Register Century Series, ICL 1900 series and IBM 370 series.
Fourth Generations Computers The fourth generation computers were developed during 1975-1990 and is the generation that we are presently in use. The major technical advantage that characterizes the fourth generation is the tiny microprocessor. The fourth generation is actually an extension of the third, building on the Integrated Circuit technology. The microprocessor is a computer processor built onto a single piece of silicon, known as a wafer or chip. Its size is about 0.5 cm along one side and not more 0.05 cm thick. The first microprocessor called Intel 4004 was developed by American Intel Corporation in 1971.
IT For Kids - Book 7 25 The features of fourth generation computers are: a. These computers used LSI (Large Scale Integration ) that could fit hundreds of components onto one chip and VLSI (Very Large Scale Integration) that squeezed hundreds of thousands of components onto a chip. b. The computers are highly reliable and accurate. c. The operating speed is excellent, measured in picoseconds. d. Micro computers are also introduced. e. Magnetic disk is the common source of external storage. f. Application software for microcomputers has become popular. The examples of this generation are IBM PC, Apple/Machintosh, IBM system/370 and the SUPERBRAIN.
Fifth Generations Computers The fifth generation computers were invented after 1991. The fifth generation computer project conducted jointly by several Japanese computer manufacturers under the sponsorship of the Japanese government emphasized artificial intelligence, focusing on such matters as machine reasoning and logic programming languages. Intelligent Knowledge Based Systems (IKBS) are the central elements of fifth generation computers. They use inference to apply knowledge to perform a task. They require at least the following capabilities: classification, concept formation, summarizing, selection, searching, reasoning, planning, modelling, the use of ‘common sense’ rules, and the ability to learn. The features of the fifth generation computers are: a. The development of the fifth generation of computer systems is characterized mainly by the acceptance of parallel processing. b. These computers will use super conductor technology. The two future devices are Gallium Arsenide (GaAs) chips and Biochips. c. These machines will incorporate Ultra Large Scale Integration (ULSI). d. The cost of software and hardware will decrease. e. These computers will have artificial intelligence.
26 IT For Kids - Book 7 Vacuum tube A device sometimes used to amplify electronic signals. Transistors Tiny switches that can be triggered by electric signals. Chip A small slice of silicon material on which integrated electronic components are deposited. Punched cards Secondary storage medium consisting of
Word Help Word paper or cardboard cards; data is recorded by punching holes in the cards. Artificial Intelligence A branch of computer science that refers to the use of computer in such a way that they are able to reason and draw conclusion, recognise voice and have language processing ability.
1. The major developments in electronic data processing took place in five distinct phases known as computer generations. 2. The first generation computers were developed between 1946 to 1958. These machines used electronic switches in the form of vacuum tubes. 3. Vacuum tube was developed by Lee De Forest in 1908. 4. The second generation computers were developed between 1959 to 1964. These machines used transistors instead of vacuum tubes. 5. Transistor was invented by three scientists’ of Bell Telephone Laboratories-John Bardeen, Walter Brattain and William Shockley in 1947. 6. During second generation of computers, high level languages such as BASIC, FORTRAN and COBOL were introduced. 7. The third generation computers were developed during 1965-1974. Integrated Circuits were used in these machines in their electronic circuitry. 8. Integrated Circuit was invented by Jack Kilby at Texas Instrument in Points for Review Points 1958. 9. The fourth generation computers were developed during 1975-1990. These machines used Large Scale Integration and Very Large Scale Integration Circuits in the memory unit. 10. The fifth generation computers were produced after 1991. These computers will use Ultra Large Scale Integration.
IT For Kids - Book 7 27 Chapter Review
Key Term Quiz
Answer the following questions by filling in the blanks(s). a. Vacuum tube was developed by______in 1908. b. The examples of the ______were IBM 1620, IBM 1401, Control Data 3600, 400 series and IBM 7000 series. c. ______, an engineer with Texas Instruments, developed the Integrated Circuit (IC) in 1958. d. The first microprocessor called ______was developed by American Intel Corporation in 1971. e. The development of the fifth generation of computer systems is characterized mainly by the acceptance of ______.
True or False
State whether the following statements are true or false. a. The development of vacuum tubes signaled the beginning of the first generation. b. High level languages (such as BASIC, COBOL, FORTRAN) resembling English were developed in the third generations of computers. c. High-level programming languages continued to be developed, including RPG(Report Program Generator) and Pascal. d. Fifth generation computers used LSI (Large Scale Integration) that could fit hundreds of components onto one chip and VLSI (Very Large Scale Integration) that squeezed hundreds of thousands of components onto a chip. e. High level language such as BASIC and FORTRAN were introduced during fifth generation of computers. Matching
Match the following. First generation Gallium Arsenide (GaAs) chips and Biochips Second generation Vacuum Tubes Third generation Transistors Fourth generation Integrated Circuits Fifth generation Microprocessors 28 IT For Kids - Book 7 Multiple Choice Circle the word or phrase that best completes each statement. a. Vacuum tube was developed by Lee DeForest in______. i. 1908 ii. 1909 iii. 1940 iv. None of the above b. The examples of the______generation computers were ENIAC, EDVAC, EDSAC, UNIVAC-I, and IBM 650. i. first ii. second iii. third iv. None of the above c. ______was invented by Robert Noyce and Jack Kilby in 1958-59. i. Transistor ii. IC iii. Vacuum tubes iv. None of the above d. Fifth generation computers will incorporate______. i. LSI ii. VLSI iii. ULSI iv. None of the above
Review Questions
Answer the following. a. What is meant by generation of computers? How many generation of computers are there? b. What were the features of the first generation computers? c. What were the features of the second generation computers? d. What is used in the electronic circuitry of the third generation computers? e. Mention any three features of fourth generation computers? f. What do you understand by the term “Artificial Intelligence”? g. What are the special features of fifth generation that makes it different from the other generations?
Discussion Question
As directed by your instructor, discuss the following questions in class or groups. Explain two most common areas of AI application in computer technology.
IT For Kids - Book 7 29 4 Classification of Computer Chapter Chapter
Overview
A computer is a device that accepts information (in the form of digitalized data) and manipulates it for some result based on a program or sequence of instructions on how the data is to be processed. It can perform both arithmetic and non-arithmetic operations with equal ease. It can perform a variety of jobs. The different types of computers are in use today due to the continuing advances in computing technology. Computers are broadly divided into three groups on the basis of computing techniques used. These are analog, digital and hybrid computers.
Analog Computers Analog refers to numerical values that have a continuous range. Analog computer works by measuring voltages and currents. This computer works on the supply of continuous electrical signals and displays output in the form of graphs. It can keep records of temperature, speed, pressure which change continuously. They are generally used in engineering and scientific applications. Speedometer and thermometer are the examples of analog computers.
30 IT For Kids - Book 7 Digital Computers Digital refers to the use of the binary digits (0 & 1) to represent any kind of data. Most modern computers are digital computers because it works basically by counting numbers that represent numerals, letters, and other special symbols. These machines are multipurpose machines. It is best suited for statistical data and numerical problems of business and science. It comes in a variety of shapes and sizes, ranging from the familiar desktop microcomputer to the minicomputer, mainframe, and supercomputer.
Digital computers are further divided into two categories: a. General purpose digital computer General purpose digital computer is designed to do wide range of information processing tasks, from scientific to commercial file processing. It can be used to prepare sales reports, banking system, graphs, payroll etc. b. Special purpose digital computer Special purpose digital computer is designed for a specific task or a narrow range of tasks. The set of instructions required for that task is permanently stored in the computer memory. Common examples include the computer installed in automobiles to control fuel and braking system.
Hybrid Computers Hybrid computer is a combination of computers those are capable of inputting and outputting in both digital and analog signals. Hybrid computers can convert analog signals into digital signals and digital signals into analog signals. They are special purpose machines. It is constructed in such a way that its components make the device fast and accurate. A hybrid computer system setup offers a cost effective method of performing complex simulations. These machines are generally used in scientific applications, aeroplanes and industrial control processes.
IT For Kids - Book 7 31 Types of Digital Computers Computers can be as big as occupying a large building and as small as a laptop or a micro controller in mobile & embedded systems. The four basic types of computers are as under: a. Supercomputers b. Mainframe computers c. Minicomputers d. Microcomputers
Super computer Super computers are the fastest, the most expensive and the most powerful computers made to process complex and time-consuming calculations. Super computers have large memories with high processing speed. They can process up to a billion operations in a second. These computers have multiple Central Processing Unit that can process multiple instructions at a time, known as parallel processing. Some applications to which parallel processing is ideally suited are resource optimization, image processing, graphics and financial portfolio analysis. Examples: a. Cray Titan b. IBM Sequoia c. Fujitsu K computer d. Cray-1
Mainframe computers Mainframe is a very large and expensive computer capable of supporting hundreds, or even thousands of users simultaneously. It has a very large and fast CPU and supports wide range of input and output terminals with backing storages capable of storing large volumes of informations. It is capable of handling and processing very large amounts of data very quickly. It is mainly used in large organizations for various applications, including bulk data processing, process control, industry and consumer statistics, enterprise resource planning, and financial transaction processing. Examples: a. Fujitsu’s ICL VME b. Hitachi’s Z800 c. System z10
32 IT For Kids - Book 7 Mini computers Mini computer is a general purpose computer which is smaller than mainframe computers. It has several functional devices often mounted in a rack in a single unit. It requires an area of 10 square feet. It has a slower operating speed, smaller backing storage, limited hardware and lesser memory capacity compared to a mainframe computer. They do not require as strict an environmental control as the mainframe computers. They are usually designed to support 50 terminals and have the capability of networking. Mini computers are used in medium sized organization for the processing of payrolls and financial accounts, cost handling, sales analysis and production planning. Examples: a. AS/400 b. PRIME series
Research and Report
Produce a word processed report outlining the way in which mini computer are used in medium sized organizations. Microcomputer A micro computer is the smallest general purpose processing system. It uses microprocessor. It can be used by one person at a time. There are different types of micro computers available offering a variety of features as per the changing needs of the technology and the size of their central processing unit. Some of the microcomputer are as follows: i. Desktop computer Desktop computer is a type of microcomputer that is designed to fit on a desk. It usually consists of a monitor, keyboard, mouse and either a horizontal or vertical system units. Today, almost all desktop computers include a built-in modem, a CD-ROM drive, a multi- gigabyte magnetic storage drive. Desktops have lots of memory space and fast processor. Desktops have large casing that allows good dissipation of any heat build-up. It is used for designing books, graphics designing and preparing documents.
IT For Kids - Book 7 33 ii. Laptops and Notebooks Laptops and Notebooks are compact computers and can run on batteries. These computers combine the power of the PC with mobility. They are equipped with powerful microprocessors, graphic capabilities, adequate memory capacity, mouse or trackball, or other pointing device and liquid crystal display (LCD) to display information. IBM ThinkPad is an example of its kind. iii. Workstations Workstation is a high-performance computer system that has graphics capabilities, large storage capacity and a powerful microprocessor. It is more powerful than a personal computer but is less advanced than a midrange computer (which can manage a large network of peripheral PCs or workstations and handle large data-processing and reporting tasks). iv. Tablet PC Tablet PC is a small wireless mobile computing device. It has a touch-screen display, circuitry and battery in a single unit. Tablets come equipped with sensors, including cameras, a microphone, an accelerometer and a touchscreen. It is often used to browse the Web, read e-mail, read eBook, browse social network sites, and watch videos. v. Smart Phones Smart phone is a combination of cellphone and handheld computer. It has a high-resolution touch screen display, camera, movie player, WiFi connectivity and Web browsing capabilities. Smartphones allow users to store information, e-mail, install programs, along with using a mobile phone in one device.
34 IT For Kids - Book 7 Analog computer The computer designed to work on numerical data represented by by measuring voltages and currents. Hybrid computer A combination of computers those are capable of inputting and outputting in both digital and analog signals. Super computer The fastest, the most expensive and the most powerful computers made to process complex and time-consuming calculations.
Word Help Word Mainframe computer A very large and expensive computer capable of supporting hundreds, or even thousands, of users simultaneously. Workstation A high-performance computer system that has graphics capabilities, large storage capacity and a powerful microprocessor.
1. A computer is a device that accepts information (in the form of digitalized data) and manipulates it for some result based on a program or sequence of instructions on how the data is to be processed. 2. Analog refers to numerical values that have a continuous range. Analog computer works by measuring voltages and currents. 3. Most modern computers are digital computers because it works basically by counting numbers that represent numerals, letters, and other special symbols. 4. Hybrid computer is a combination of computers those are capable of inputting and outputting in both digital and analog signals. 5. Super computers are the fastest, the most expensive and the most powerful computers made to process complex and time-consuming calculations. 6. Mainframe is a very large and expensive computer capable of supporting hundreds, or even thousands, of users simultaneously.
Points for Review Points 7. Mini computer is a general purpose computer which is smaller than mainframe computers. 8. Desktop computer is a type of microcomputer that is designed to fit on a desk. 9. Workstation is a high-performance computer system that has graphics capabilities, large storage capacity and a powerful microprocessor.
IT For Kids - Book 7 35 Chapter Review
Key Term Quiz
Answer the following questions by filling in the blanks(s). a. ______is a combination of computers those are capable of inputting and outputting in both digital and analog signals. b. ______are the fastest, the most expensive and the most powerful computers made to process complex and time-consuming calculations. c. ______is a very large and expensive computer capable of supporting hundreds, or even thousands, of users simultaneously. d. ______is a type of microcomputer that is designed to fit on a desk. e. ______is a high-performance computer system that has graphics capabilities, large storage capacity and a powerful microprocessor.
True or False
State whether the following statements are true or false. a. Speedometer and thermometer are the examples of analog computers. b. A special purpose computer is designed for a specific task or a narrow range of tasks. c. Digital computer is a combination of computers those are capable of inputting and outputting in both digital and analog signals. d. Super computers have large memories with high processing speed. e. Tablet PC is a is a small wireless mobile computing device.
Technical Terms Write the technical term for the following statements. a. A computer that works on the supply of continuous electrical signals and displays output in the form of graphs. b. A combination of computers those are capable of inputting and outputting in both digital and analog signals. c. The fastest, the most expensive and the most powerful computers made to process complex and time-consuming calculations. d. A very large and expensive computer capable of supporting hundreds, or even thousands, of users simultaneously. 36 IT For Kids - Book 7 Matching
Match the following. Hybrid computer A computer small enough to fit on a desktop, with a single-chip CPU. Micro computer A high-performance computer system that has graphics capabilities, large storage capacity and a powerful microprocessor. Mainframe computer A small wireless mobile computing device. Workstation Designed for large scale data processing Tablet PC Combines the best feature of analog and digital computer.
Multiple Choice
Circle the word or phrase that best completes each statement. a. ______is a computer that performs calculations and logical operations with quantities represented as digits, usually in the binary number system. i. Analog computer ii. Digital computer iii. Hybrid computer iv. All of the above b. ______digital computer is a type of digital computer designed for a specific job. i. General purpose ii. Special purpose iii. None of the above iv. All of the above c. ______is the fastest, most expensive and most powerful of all computers having parallel processing to access the data and instructions. i. Super computer ii. Mini computer iii. Micro computer iv. All of the above d. ______is a high-performance computer used for large-scale computing purposes. i. Super computer ii. Mainframe computer iii. Handheld computer iv. All of the above
IT For Kids - Book 7 37 Review Questions Answer the following questions. a. What is an analog computer? Give any two examples. b. What is a digital computer? What are the two types of digital computers? Explain them in short. c. What is a hybrid computer? Give an example. d. What are super computers and where are they used? e. What is a mainframe computer and what are its typical applications? f. What is a mini computer and what are its typical applications? g. What is microcomputer? What are the major categories of microcomputer?
Write short notes on. a. Analog Computer b. Digital Computer c. Hybrid Computer d. Laptop Computer e. Workstation
Discussion Question
As directed by your instructor, discuss the following questions in class or groups. Name the new brand of computer manufactured by Apple company? Why it has become a popular in desktop publishing houses?
Word Power Read the description and name it. a. The computer designed to work on numerical data represented by measuring voltages and currents. b. A high-performance computer system that has graphics capabilities, large storage capacity and a powerful microprocessor.
38 IT For Kids - Book 7 Revision Answer the following questions by filling in the blanks(s). a. The accumulation of raw data and the sequential set of instructions is called ______. b. ______consists of wooden frame having parallel wires with beads strung on them. c. The first microprocessor called ______was developed by American Intel Corporation in 1971. d. ______are the largest, fastest and the costliest computer system. e. A computer has a high degree of ______because it carries out calculation with high speed and accuracy.
State whether the following statements are true or false. a. Information is data is the organize has meaning and is useful. b. Charles Babbage, an American census statistician, developed a mechanical tabulating machine in 1887 AD. c. The development of vacuum tubes signaled the beginning of the first generation. d. A digital computer is based on the principle of measurement. e. A computer is an electronic device that (i) accepts data (ii) process data (iii) generates outputs and (iv) stores data.
Write the technical term for the following statements. a. The device that is used to get information out of the computer in a form which the user can understand is called output device. b. A collection of unorganized facts, which can include words, numbers, images and sounds c. A fast data processing-oriented computer, which are based on parallel processing to access the data and instructions faster. d. A collection of unorganized facts, which can include words, numbers, images and sounds. e. A type of computer that offers the features of both a digital and an analog computer.
IT For Kids - Book 7 39 Circle the word or phrase that best completes each statement. a. A______is one millionth of a second. i. Millisecond ii. Microsecond iii. Picosecond iv. All of the above b. Computer was introduced in Nepal in the year______. i. 1972 ii. 1973 iii. 1974 iv. All of the above c. Vacuum tube was developed by Lee DeForest in______. i. 1908 ii. 1909 iii. 1940 iv. None of the above d. ______digital computer is a type of digital computer designed for a specific job. i. General purpose ii. Special purpose iii. None of the above iv. All of the above e. Fifth generation computers will incorporate______. i. LSI ii. VLSI iii. ULSI iv. None of the above
Answer the following questions. a. Discuss the main characteristics of a computer, which have made them so versatile and popular? b. Which was the first mechanical device invented by the Chinese? How were the calculations done in this device? c. What are the special features of fifth generation that makes it different from the other generations? d. What is a hybrid computer? Give an example. e. Define the following terms: i. Millisecond ii. Vacuum tube iii. Desktop computer
40 IT For Kids - Book 7 5 Hardware and Software Chapter Chapter Overview
Computer is a complete, working device. It consists of two major components: hardware and software. The physical parts that make up the entire computer system is called a computer hardware. A computer hardware consists of interconnected electronic devices that you can use to control the computer’s operation, input and output. Computer software, on the other hand, is a set of instructions for a computer to perform specific operations. You need both hardware and software for a computer system to work.
Hardware Computer hardware is the collection of physical parts of a computer system. There are many different kinds of hardware that can be installed inside, and connected to the outside of a computer. This includes the computer case, monitor, keyboard, and mouse. It also includes all the parts inside the computer case, such as the hard disk drive, motherboard, video card, and many others. Computer hardware is what you can physically touch.
Input Devices Input is any data or instruction that is entered into the memory of a computer. An input device is a computer hardware used to send data to a computer. It allows users to communicate and feed instructions and data to computers for processing, display, storage and/or transmission. The keyboard, light pen, scanner, touch screen and mouse are some of the popular input devices.
IT For Kids - Book 7 41 Electronic Keyboard Electronic keyboard is one of the most widely used input device of the computer. It is hardware used to input text, characters and other commands into a computer. It has a set of typewriter-like keys that enables you to enter data into a computer for processing. Many keyboards are wireless, communicating with the computer via Bluetooth or an RF receiver. The most common English-language key pattern for typewriters and keyboards is QWERTY, after the layout of the first six letters on the top row of its keys (from left to right).
Mouse Mouse is the most widely used pointing device on desktop computers because it takes full advantage of a graphical user interface. It is designed to fit comfortably under the palm of your hand. The top of the mouse has two buttons and a small wheel. The bottom of a mouse is flat and contains a multi-directional mechanism, usually either a small ball or an optical sensor, which detects movement of the mouse. It is used to control the movement of the pointer, often called a mouse pointer, on the screen and to make selections from the screen.
Trackball Trackball is a pointing device consisting of a ball held by a socket containing sensors to detect a rotation of the ball about two axis— like an upside-down mouse with an exposed protruding ball. The user rolls the ball with the thumb, fingers, or the palm of the hand to move a cursor. The advantage of trackball over mouse is that it is stationary so it does not require much space to use it.
42 IT For Kids - Book 7 Light pen Light pen is a handheld input device that contain a light source or can detect light. Some light pens require a specially designed monitor, while others work with a standard monitor. Instead of touching the screen with your finger to interact with the computer, you press the light pen against the surface of the screen or point the light pen at the screen and press button on the pen. Light pens are used in applications where desktop space is limited such as in the health- care field or when a wide variety of people use the application, such as electronic voting.
Joystick Joystick is a vertical lever mounted on a base. You move the lever in different directions to control the actions of a vehicle or player. The lever usually includes buttons called triggers that you can press to activate certain events. Some joysticks also have additional buttons that can set to perform other actions.
Graphics Tablet A graphics tablet is a flat, rectangular, electronic plastic board used to input drawing, sketches or other graphical data. Each location on the graphics tablet corresponds to a specific location on the screen. When you draw on the tablet with either an electronic pen or a puck, the tablet detects and converts the movements into digital signals that are sent into the computer.
Webcam Webcam is a video camera that feeds or streams its image in real time to or through a computer to computer network. When “captured” by the computer, the video stream may be saved, viewed or sent on to other networks via systems such as the internet, and email as an attachment.
IT For Kids - Book 7 43 Central Processing Unit Central Processing Unit (CPU) is the computing part of a computer. It is the part of a computer that performs computations, executes instructions and transfers information between all the parts of a computer. The CPU is usually mounted on the main circuit board, called the motherboard. It serves as a “brain” of the computer. The Central Processing Unit (processor) consists of three basic units: a. Arithmetic and Logic Unit ( ALU ) b. Control Unit ( CU ) c. Primary Memory ( PM )
Instructions User Input Devices Software
Data Instructions RAM
Data Instructions CPU
Output Output Output Devices Output Storage Devices
Research and Report
Write a report on the latest microprocessor used in the portable devices.
Arithmetic and Logic Unit Arithmetic and Logic Unit is the calculating part of the computer where actual data processing is done. It performs two functions: a. Mathematical manipulation It performs operations such as addition, subtraction and multiplication of integers. b. Logical and comparative analysis It performs logical operations based on AND, OR, NOT functions. Comparative analysis consists of comparison, e.g. numbers and determining whether one is equal to or less than or greater than the other number.
44 IT For Kids - Book 7 Control Unit Control Unit is also known as the nerve centre of a computer system. The control unit directs and controls the flow of information throughout the computer. This part of a CPU is responsible for performing the machine cycle - fetch, decode, execute. a. Fetches all the instructions and data from the main memory to the ALU to be processed. b. Decodes the instructions, interprets these instructions and executes the instructions. c. The processed data is then send from ALU to the main memory. d. Finally, it directs the flow of the meaningful information from the memory to the output device.
Primary Memory Primary memory is computer memory that is accessed directly by the CPU. It operates at a very high speed. It allows a processor to access running execution applications and services that are temporarily stored in a specific memory location. The primary memory is divided into two parts: RAM and ROM a. RAM RAM stands for Random Access Memory. It is also called read/write memory as information can be written into and read from RAM. It is used to store programs and data temporarily because anything stored in RAM is lost when the computer is switched off. b. ROM ROM stands for Read Only Memory. It is a permanent store of instructions. ROM’s contents are not lost when the computer is switched off. The information can only be read from and not written onto ROM. The information comprises programs and other instructions required to boot the computer and execute the user programs.
IT For Kids - Book 7 45 Output Devices Output is the action of getting informations from the computer. Once the CPU has executed the program instruction, the program may ask that information be communicated to an output device. The output device is a device that translates the data processed in the computer from machine coded form into a human intelligible form.
Monitor Monitor is the major source for data output. It is a television like screen that displays result of work done by the computer. It provides a temporary display of meaningful information. The basic types of monitors are Cathode Ray Tube (CRT) monitors, Liquid Crystal Display (LCD) monitors and Light- Emitting Diode (LED) Monitors.
Printer Printer is an output device for producing text and images on paper. Computer printers are commonly divided into two general classes according to the way they produce images on paper: a. Impact printer b. Non-impact printer
Impact Printer Impact printer is a printer that uses the electromechanical mechanism, that is physically striking the hammers to strike a character against an inked ribbon. Each hammer is embossed with the shape of an alphanumeric character and is transferred through the inked ribbon onto the paper, resulting in a printed character. They are relatively slow, noisy and inexpensive. The impact printers are dot matrix and daisy wheel printer.
Research and Report
Search on the Internet and write short note on the uses of dot matrix printer.
46 IT For Kids - Book 7 Non-Impact Printer Non-impact printer is a type of printer that does not operate by striking a head against a ribbon. The printing is done with ink-jet, electrostatic, chemical and thermal technology. The quality of printing is very high than impact printer. Non-impact printers are less noisy than impact printers, and also faster due to the lack of moving parts in the print head. Ink-jet printer and laser printer are examples of non-impact printers.
Speakers and Headphones Speakers are the output devices that helps you hear the sound output generated by the computer. The output heard through the speakers is also known as the soft copy output. Like speakers, headphones also give soft copy output generated by the computer. They are worn on the ears so that only one person can hear the output at a time. A headset is a sound input- cum-output device consisting of a microphone and a pair of headphones.
Multimedia Projector Multimedia projector is a compact, high resolution, full-color projector capable of projecting text, images, video and audio content. Typically the projector will feature inputs for a computer, DVD player, VCR, CD player and storage device. Multimedia projectors are used frequently in classrooms, offices and gatherings at which multimedia presentations are made. In a film class, for example, the teacher can integrate selected video sequences into a slide show of note pages.
Research and Report
Why is multimedia projector important in teaching learning process?
IT For Kids - Book 7 47 Secondary Storage Devices Secondary storage is a non-volatile memory which provides a very large capacity for storage of data and instructions for future use. Secondary memory is the least expensive and slowest form of memory. Data in secondary storage cannot be processed directly by the CPU. It must first be copied into primary storage. It is used for back-ups for security, distribution and data storage so that they are not permanently lost if the power supply is terminated. Secondary storage devices include hard disk, optical disk and USB flash drive. Hard disk Hard disk is a set of disks called platters made up of aluminium material that are coated with iron-oxide on both sides which allows data to be magnetically recorded. The disk is permanently sealed in a metal case due to the sensitive operations they perform; the presence of even a single dust particle in the unit can destroy the drive quickly as it spins. The hard disk is used for permanent data storage.
Optical disk Optical disk is a disk on which digital data, as text, music, or pictures, is stored as tiny pits in the surface and is read or replayed by a laser beam scanning the surface. The storage capacity of laser disk is very high and access of information is very fast. CD-ROM (Compact Disk Read Only Memory) and DVD (Digital Versatile Disk) are the common types of optical disks.
USB flash drive USB flash drive is a small piece of equipment used to store and transfer information for computers using a USB. USB flash drives are easy-to-use as they are small enough to be carried in a pocket and can plug into any computer with a USB drive.
48 IT For Kids - Book 7 Computer Software Software is the intangible component of the computer system. It is a set of programs that instructs the computer about the tasks to be performed. It tells the computer how the tasks are to be performed; hardware carries out these tasks. Without software, the computer would be useless. The two major categories of software are: system software and application software.
Software
System Software Application Software
Packaged Operating Device Driver Language Tailored software System and Processor Software Utilities
System Software A system software is an extremely useful software to a programmer. System software plays a central role in all interaction with the computer. It controls all internal operations like reading data from input devices, transmitting information to output devices, checking the components of a computer etc. Without it, application packages cannot be run on a computer, requiring lesser time and effort. Different kinds of computers will have different kinds of system software. System software can be sub-divided as follows: a. Operating system software b. Device driver c. Utility software d. Translator programs
Operating system software Operating system is a system software found in almost all computer installations. It is a set of control programs that controls and supervises a computer system’s hardware and provides services to computer users. It serves as a bridge between the computer hardware, the application software and the user. The three most common operating systems for personal computers are Microsoft Windows, Mac OS X, and Linux. The operating systems for mobile computers are Android, iOS, Blackberry OS and Symbian. IT For Kids - Book 7 49 Device driver Device driver is a computer program that controls a particular type of device that is attached to your computer. It acts as a translator between the operating system of the computer and the device connected to it. Each computer devices such as keyboards, printers, scanners, digital cameras and external storage devices need a driver in order to work properly.
Utility software Utility program is a specialized program that performs a very specific task, usually related to managing system resources. It helps you to operate your computer in an efficient and safe manner by taking care of hardware and software components. Operating systems contain a number of utilities for managing disk drives, printers, and other devices. It is also known as service program. Examples include virus checkers, disk defragmenters, backup utility and disk checker software.
Translator program Translator program is a computer program that translates a set of code written in one programming language into a functional equivalent of the code in another programming language. There are three types of language translator programs. They are: compiler, interpreter and assembler.
Assembler Assembler is a language translator that translates the assembly language program into machine language program.
Compiler A compiler is a computer program that translates a computer program written in high-level language (called the source code) into machine language (object code) and parts all errors found in the program. After all the errors are removes, the program is executed to get the result.
Source Program Compiler Executable Program
Data Executable Program Program Output
50 IT For Kids - Book 7 Interpreter Interpreter is a language translator that translates and executes a program written in high level language, line by line. It translates one line of the program, executes the translated instruction, and then moves on to the next line. It displays the errors of one line and only after correction of the errors, the control goes to the next line. Common interpreters include Perl, Python, and Ruby interpreters, which execute Perl, Python, and Ruby code respectively.
Source Program Interpreter Executable Program
Data Executable Program Program Output
Application Software Application software is a type of computer software that is designed for the end user. It helps the user to work faster, more efficiently and more productively. It comes in a very wide variety of types such as accounting programs, database programs, graphics and illustration programs, word processing programs. Application software can further be sub-divided into two categories: a. Packaged software b. Customized software
Customized (tailored) software Customized or tailored software is the software that is made to the specifications of a client. It is designed for a single organization. Industrial automation software, business software, payroll software and banking software are examples of some customized or tailored software.
Packaged software Packaged software is developed by a vendor and is available for purchase in a prepackaged form. It is a set of programs that allows the computer to perform a specific data processing job for the user. For example, Microsoft Office is packaged software, including multiple software programs used in a home or office, such as Microsoft Excel, Microsoft Word, and Microsoft Powerpoint.
Research and Report
Have you observed any customized application being used? How were they helping their users? Write about the features of the software.
IT For Kids - Book 7 51 Hardware The collection of physical parts of a computer system. Input Any data or instruction that is entered into the memory of a computer. CPU The part of a computer that performs computations, executes instructions and transfers information between all the parts of a computer.
Word Help Word Output device A device that translates the data processed in the computer from machine coded form into a human intelligible form. Computer software A set of programs that instructs the computer about the tasks to be performed.
1. Computer hardware is the collection of physical parts of a computer system. 2. Electronic keyboard is hardware used to input text, characters and other commands into a computer. 3. Joystick is a device consisting of a hand held stick that pivots about one end and transmits its angle in two dimensions to a computer. 4. Central Processing Unit (CPU) is the part of a computer that performs computations, executes instructions and transfers information between all the parts of a computer. 5. RAM is used to store programs and data temporarily because anything stored in RAM is lost when the computer is switched off. 6. Multimedia projector is a compact, high resolution, full-color projector capable of projecting text, images, video and audio content. 7. Secondary storage is a non-volatile memory which provides a very large capacity for storage of data and instructions for future use.
Points for Review Points 8. Software is a set of programs that instructs the computer about the tasks to be performed. 9. Application software is a type of computer software that is designed for the end user. 10. Packaged software is developed by a vendor and is available for purchase in a prepackaged form.
52 IT For Kids - Book 7 Chapter Review
Key Term Quiz Answer the following questions by filling in the blanks(s). a. An______is a computer hardware used to send data to a computer. b. ______is a pointing device consisting of a ball held by a socket containing sensors to detect a rotation of the ball about two axis—like an upside-down mouse with an exposed protruding ball. c. ______is the calculating part of the computer where actual data processing is done. d. ______is a printer that uses the electromechanical mechanism, that is physically striking the hammers to strike a character against an inked ribbon. e. ______is a computer program that controls a particular type of device that is attached to your computer.
True or False State whether the following statements are true or false. a. Mouse is an integral part of the graphical user interface. b. Light pen is a device consisting of a hand held stick that pivots about one end and transmits its angle in two dimensions to a computer. c. The CPU is usually mounted on the main circuit board, called the motherboard. d. Ink-jet printer and laser printer are examples of impact printers. e. Utility program is a specialized program that performs a very specific task, usually related to managing system resources.
Technical Terms Write the technical term for the following statements. a. A device consisting of a hand held stick that pivots about one end and transmits its angle in two dimensions to a computer. b. The nerve centre of a computer system that directs and controls the flow of information throughout the computer. c. The action of getting informations from the computer. d. A set of disks made up of aluminium material that are coated with iron-oxide on both sides which allows data to be magnetically recorded. e. A language translator that translates the assembly language program into machine language program.
IT For Kids - Book 7 53 Matching Match the following. Application software It enables a user to write words or draw pictures directly into the computer. Light Pen A device that is mostly used for playing video games and for CAD/CAM systems. Joystick A computer memory that is accessed directly by the CPU. Primary memory A sound input-cum-output device consisting of a microphone and a pair of headphones. Headset A type of computer software that is designed for the end user.
Multiple Choice
Circle the word or phrase that best completes each statement. a. ______is a computer input device that enables a user to hand-draw images, animations and graphics i. Light Pen ii. Digitizing tablet iii. Joystick iv. All of the above b. ______part of a CPU is responsible for performing the machine cycle - fetch, decode, execute. i. ALU ii. CU iii. Registers iv. All of the above c. ______is a disk on which digital data, as text, music, or pictures, is stored as tiny pits in the surface and is read or replayed by a laser beam scanning the surface. i. Hard disk ii. Optical disk iii. USB flash drive iv. All of the above d. ______is a language translator that translates and executes a program written in high level language, line by line. i. Assembler ii. Compiler iii. Interpreter iv. All of the above
54 IT For Kids - Book 7 Review Questions Answer the following questions. a. What is a computer hardware? b. What is an input device? Give any three examples. c. What is a trackball? What is the advantage of trackball over mouse? d. What is CPU? What are the basic units of CPU? e. What is Arithmetic and Logic Unit? What are the two functions of ALU? f. What are the functions of Control Unit? g. What is a primary memory? What are the two types of primary memory? h. What are the difference between impact printer and non-impact printer? i. What is a secondary storage device? Give examples. j. What is computer software? What are two major categories of software? k. What is a system software? What are the different types of system software? l. What is application software? What are the two types of application software?
Discussion Question
As directed by your instructor, discuss the following questions in class or groups. Explain the function of RAM in computer system. Find the capacity of RAM on your PC.
Word Power
Read the description and name it. a. A pointing device consisting of a ball held by a socket containing sensors to detect a rotation of the ball. b. A disk on which digital data, as text, music, or pictures, is stored as tiny pits in the surface and is read or replayed by a laser beam scanning the surface. c. A computer program that controls a particular type of device that is attached to your computer.
IT For Kids - Book 7 55 Computer 6 Number System Chapter Chapter Overview
A number system is a set of objects (often numbers), operations, and the rules governing those operations. In a number system, there are only a few symbols which represent different values depending on the position they occupy in the number. The total number of digits applicable to any system is called its radix/ base. The actual number of symbols used in a positional system depends on its base. Computer architecture supports following number systems. i. Binary number system ii. Decimal number system iii. Octal number system iv. Hexadecimal number system
Binary Number System Binary number system has only two digits that are 0 and 1. Every number (value) represents with 0 and 1 in this number system. The base of binary number system is 2, because it has only two digits. Some important terms in the binary number system include the following: a. BIT is the short form of “binary digit”. It is the smallest possible unit of data. In computerized data, a bit can be either 0 or 1. b. Nibble is a group of four bits. c. Byte is a group of eight bits. A nibble is a half byte. Bits 0-3 are called the low- order nibble, and bits 4-7 form the high-order nibble. d. Word is a group of two bytes. Bits 0-7 form the low-order byte and bits 8-15 form the high-order byte. However, computers today have redefined word as a group of four bytes (32 bits).
56 IT For Kids - Book 7 Decimal Number System Decimal number system has only ten (10) digits from 0 to 9. Every number (value) represents with 0,1,2,3,4,5,6, 7,8 and 9 in this number system. The base of decimal number system is 10, because it has only 10 digits.
Octal Number System Octal number system has only eight (8) digits from 0 to 7. Every number (value) represents with 0,1,2,3,4,5,6 and 7 in this number system. The base of octal number system is 8, because it has only 8 digits.
Hexadecimal Number System Hexadecimal number system has sixteen (16) alphanumeric values from 0 to 9 and A to F. Every number (value) represents with 0,1,2,3,4,5,6, 7,8,9,A,B,C,D,E and F in this number system. The base of hexadecimal number system is 16, because it has 16 alphanumeric values. Here A is 10, B is 11, C is 12, D is 13, E is 14 and F is 15.
Table showing the corresponding values of number systems Binary Octal Decimal Hexadecimal 0 0 0 0 1 1 1 1 10 2 2 2 11 3 3 3 100 4 4 4 101 5 5 5 110 6 6 6 111 7 7 7 1000 10 8 8 1001 11 9 9 1010 12 10 A 1011 13 11 B 1100 14 12 C 1101 15 13 D 1110 16 14 E 1111 17 15 F
IT For Kids - Book 7 57 Converting Binary to Decimal System a. Each digit of binary number is multiplied by base of the number (i.e. 2) with its positional weight. b. All the products of multiplication are added to get the decimal equivalent of the number.
Solved Example Convert the binary number (101010)2 to it decimal equivalent.
Binary digits = 1 0 1 0 1 0 = 5 4 3 2 1 0 = (1x25)+( 0x24) + (1x23) + (0x22)+(1x21)+(0x20) = (1x32) + (0x16) + (1x8) + (0x4) + (1x2) + (0x1) = 32 + 0 + 8 + 0 + 2 + 0
= 4210
Thus, (101010)2 = (42)10
Converting Decimal to Binary System a. Divide the decimal number by the desired target radix i.e. 2. b. Append the remainder as the next most significant digit. c. Repeat until the decimal number has reached zero. d. The answer is obtained by writing the answer in the reverse order.
Solved Example Convert the decimal number 2110 into binary equivalent.
Remainder 2 21 1 2 10 0 2 5 1 2 2 0 2 1 1 0
Thus, (21)10 = (10101)2
58 IT For Kids - Book 7 Converting Octal to Decimal a. Each digit of binary number is multiplied by base of the number (i.e. 8) with its positional weight. b. All the products of multiplication are added to get the decimal equivalent of the number.
SolvedSolved ExampleExample Convert 6258 into decimal equivalent.
Octal digits = 6 2 5 = 2 1 0 = (6x82)+(2x81)+(5x80) = (6x64) + (2x8) + (5x1) = 384 + 16 + 5
Thus, 6258 = 40510
Converting Decimal to Octal System a. Divide the decimal number by the desired target radix i.e. 8. b. Append the remainder as the next most significant digit. c. Repeat until the decimal number has reached zero. d. The answer is obtained by writing the answer in the reverse order.
Solved Example Convert decimal number 634 into octal equivalent.
Remainder 8 4119 7 8 514 2 8 64 0 8 8 0 8 1 1 0
Thus, 411910 = 100278
IT For Kids - Book 7 59 Converting Hexadecimal to Decimal Conversion a. Each digit of binary number is multiplied by base of the number (i.e. 16) with its positional weight. b. All the products of multiplication are added to get the decimal equivalent of the number.
Solved Example Convert B3E16 into decimal equivalent.
Hexadecimal digits = B 3 E = 2 1 0 = (Bx162) + (3x161) + (Ex160) = (11x162) + (3x161) + (14x160) = (11x256) + (3x16) + (14x1) = 2816 + 48 + 14
= 287810
Thus, B3E16 = 287810
Converting Decimal to Hexadecimal a. Divide the decimal number by the desired target radix i.e. 16. b. Append the remainder as the next most significant digit. c. Repeat until the decimal number has reached zero. d. The answer is obtained by writing the answer in the reverse order.
Solved Example Convert decimal number 7551 into hexadecimal equivalent.
Remainder 16 7551 15 = F 16 471 7 16 29 13 = D 16 1 1 0
Answer = 1 D 7 F16
60 IT For Kids - Book 7 Binary Arithmetic Binary number consists of only ‘0’s and ‘1’s. Hence binary arithmetic such as addition, subtraction, multiplication and division are also done with ‘0’ and ‘1’. Let us take this operations one by one.
Binary Addition The binary addition rules are shown in the table below: A B A + B 0 0 0 0 1 1 1 0 1 1 1 0 with 1 carry over
Solved Example Add 101110 with 100101.
1 0 1 1 1 0 (Addend) + 1 0 0 1 0 1 (Augend) 1 0 1 0 0 1 1 (Sum)
Binary Subtraction The binary subtraction rules are shown in the table below: A B A - B 0 0 0 1 1 0 1 0 1 0 1 1 with 1 borrow
Solved Example Subtract 10110 from 11011.
1 1 0 1 1 (Minuend) - 1 0 1 1 0 (Subtrahend) 0 0 1 0 1 (Difference)
IT For Kids - Book 7 61 Binary Multiplication The binary multiplication rules are shown in the table below: A B A x B 0 0 0 1 1 1 1 0 0 0 1 0
Solved Example Multiply 1011 with 10001.
1 0 1 1 x 1 0 0 0 1 1 0 1 1 0 0 0 0 x 0 0 0 0 x x 0 0 0 0 x x x 1 0 1 1 x x x x 1 0 1 1 1 0 1 1
Binary division The binary division rules are shown in the table below: A B A / B 0 1 0 1 1 1 1 0 Not defined
Solved Example Divide 11001 by 101.
1 0 1 ) 1 1 0 0 1 ( 1 0 1 1 0 1 1 0 1 1 0 1 x Answer: Quotient = 101
62 IT For Kids - Book 7 Binary Number System A system of numbers consisting of only two digits, 0 and 1. Decimal Number System A system of numbers having symbol 0 - 9. Octal Number System A system of numbers having symbol 0 - 7. Hexadecimal Number A system of numbers having symbols (0 - 9, A - F). Bit The smallest possible unit of data. Word Help Word Nibble A group of four bits. Byte A group of eight bits. Word A group of two bytes.
1. A number system is a set of objects (often numbers), operations, and the rules governing those operations. 2. The total number of digits applicable to any system is called its radix/ base. 3. Computer architecture supports following number systems. i. Binary number system ii. Decimal number system iii. Octal number system iv. Hexadecimal number system 4. BIT is the short form of “binary digit”. It is the smallest possible unit of data. In computerized data, a bit can be either 0 or 1. 5. Nibble is a group of four bits. 6. Byte is a group of eight bits. A nibble is a half byte. Bits 0-3 are called the low-order nibble, and bits 4-7 form the high-order nibble. 7. Word is a group of two bytes. Bits 0-7 form the low-order byte and bits 8-15 form the high-order byte. However, computers today have Points for Review Points redefined word as a group of four bytes (32 bits). 8. Decimal number system has only ten (10) digits from 0 to 9. 9. Octal number system has only eight (8) digits from 0 to 7. 10. Hexadecimal number system has sixteen (16) alphanumeric values from 0 to 9 and A to F.
IT For Kids - Book 7 63 Chapter Review
Key Term Quiz
Fill in the blanks. a. ______has only two digits that are 0 and 1. b. ______is a group of four bits. c. ______is a group of two bytes. d. ______has only ten (10) digits from 0 to 9. e. ______has sixteen (16) alphanumeric values from 0 to 9 and A to F.
True or False
State whether the following statements are True or False. a. The actual number of symbols used in a positional system depends on its base. b. Nibble is the smallest possible unit of data. c. Bits 0-3 are called the low-order nibble, and bits 4-7 form the high-order nibble. d. The base of decimal number system is 8, because it has only 8 digits. e. The base of hexadecimal number system is 16, because it has 16 alphanumeric values. f. The decimal equivalent of binary number 1100110 is 102.
Technical Terms
Name the technical term for each of the following. a. A set of objects (often numbers), operations, and the rules governing those operations. b. The total number of digits applicable to any system. c. The smallest possible unit of data. d. A group of four bits. e. A group of eight bits. f. A number system that has only eight (8) digits from 0 to 7.
64 IT For Kids - Book 7 Review Question
Answer the following questions. a. What is a computer number system? b. What is a binary number system? What is the base of binary number system? c. What is a “bit”? d. What is a byte? e. What is a nibble? f. What is the value of the base for decimal, hexadecimal, binary and octal number systems? g. What is octal number system? h. What is hexadecimal number system?
Convert the following as indicated. a. 10112 = (?)10 b. 1012= (?)10 c. 13210 = (?)2 d. 63410 = (?)2 e. 38710 = (?)8 f. 36710= (?)8 g. 26710 = (?)8 h. 1328 = (?)10 i. 6418 = (?)10 j. 3618= (?)10 k. 11112 =(?)8 l. 110102= (?)8 m. 26210 = (?)16 n. 86210 = (?)16 o. 2DA16 = (?)10 p. FBC16 = (?)10 q. D4116 = (?)10
Perform the following binary arithmetic operations. a. 1111 + 1001 b. 10100 + 1101 c. 10001 + 101001 d. 10011 - 11011 e. 1101 - 10111 f. 1111 - 1001 g. 101 x 110 h. 111 x 101 i. 10101 x 1011 j. 1101 ÷ 11 k. 11101 ÷ 11 l. 1001 ÷ 1011
IT For Kids - Book 7 65 Computer 7 Networks and the Internet Chapter Chapter Overview
Today the world scenario is changing. Computer network have changed the way business and other daily affair works. Now, they rely on computer networks and internet work. A computer network is a set of connected computers. Computers on a network are called nodes. The connection between computers can be done via cabling, most commonly the Ethernet cable, or wirelessly through radio waves. Connected computers can share resources, like access to the Internet, printers, file servers, and others. A network is a multipurpose connection, which allows a single computer to do more.
Advantages of a Computer Network The advantages of interconnecting computing devices are listed below: a. Computer network allows to communicate efficiently with a group of people. They can enjoy the benefit of e-mails, instant messaging, telephony, video conferencing and chat rooms. b. Computer network allows to find and share information and data. This is beneficial for large organizations to maintain their data in an organized manner and facilitate access for desired people. c. Another important advantage of networking is the ability to share hardware. d. Users can share software within the network easily. Therefore large companies can reduce the cost of buying software by networking their computers. e. Sharing and transferring files within networks is very rapid, depending on the type of network. This will save time while maintaining the integrity of files. 66 IT For Kids - Book 7 Components of a Computer Network The main components essential for the successful operation of a computer network can be divided into two types. These are : a. Hardware components, and b. Software components.
Hardware Components Hardware components in a computer network include : a. Computer systems (called servers or clients), b. Shared resources, like printers, scanners etc., and c. Physical media that connects them. The various computers on a network are either named as servers or clients. Different computers that access shared resources on the network are called Clients. Servers are the computers that receive requests from network users (clients) and make the shared resources available to them.
Software Components The software components required to run a computer network are of two types. These are : a. Protocols, and b. Network software. The protocols specify the rules, procedures and conventions for communication and data transfer over the network. An example of a protocol is TCP/IP. TCP stands for Transmission Control Protocol and IP stands for Internet Protocol. Network software is the software that performs various network related functions such as data routing and error detection etc.
Research and Report
What is the native protocol of the Internet? Give its function.
IT For Kids - Book 7 67 Classification on Geographical Spread of Network There are several different types of computer networks. Computer networks can be categorized based on their scale and scope, historical reasons, preferences for networking industries, and their design and implementation issues. The entire computer network can be classified into three types on the basis of the geographical spread of the network. They are: a. Local area network (LAN) b. Metropolitan area network (MAN) c, Wide area network (WAN)
Local Area Network (LAN) Local Area Network is a computer network at a single site, typically an individual office building. Modern local area networks predominantly use either Wi-Fi or Ethernet to connect their devices together. A LAN is very useful for sharing resources, such as data storage and printers. LANs can be built with relatively inexpensive hardware, such as hubs, network adapters and Ethernet cables.
Metropolitan Area Network (MAN) Metropolitan Area Network is a computer network that interconnects users with computer resources in a geographic area. MANs are formed by connecting multiple LANs. Thus, MANs are larger than LANs but smaller than wide area networks (WAN). MANs are extremely efficient and provide fast communication via high-speed carriers, such as fiber optic cables. Cellular phone networks are a good example of such networks.
Wide Area Network (WAN) WAN is a computer network that spans a large geographic area such as a city, country, or even intercontinental distances, using a communication channel that combines many types of media such as telephone lines, cables, and air waves. A WAN connects different smaller networks, including local area networks (LANs) and metro area networks (MANs). The Internet is the largest WAN, spanning the Earth.
68 IT For Kids - Book 7 Physical LAN Topologies Network topology refers to the physical layout of the network in which all the devices are connected. This includes all the hardware that makes up the network. The points of connection to the network by the stations are called nodes or link stations. There are several types of topographical design and strategies used to implement LAN. There are four basic topologies: bus, ring, star and mesh topology.
Bus Topology Bus topology consists of a main run of cable with a terminator at each end. All nodes are connected to the linear cable. The terminator is used to absorb the signal when the signal reaches the end, preventing signal bounce. While using bus topology, when a computer sends out a signal, the signal travels the cable length in both directions from the sending computer. When the signal reaches the end of the cable length, it bounces back and returns in the direction it came from. This is known as signal bounce. Signal bounce will create problem in the network, because if another signal is sent on the cable length at the same time, the two signals will collide. The advantages of bus topology are: a. Low installation cost. c. Easy to connect a computer or peripheral to a linear bus.
The disadvantages of bus topology are: a. Fault diagnosis is difficult. b. If problem occurs on the backbone “cable”, the entire network will go down. c. Terminators are required at both ends of the backbone cable.
IT For Kids - Book 7 69 Ring Topology In the ring topology, nodes are connected to each other in a closed loop by a single communication cable. Data transfers in one direction, from one node to another around the ring. A ring topology is also called loop network. It is short cable connection which cause an increase in network reliability. As with the bus topology, however, if the ring is broken, the entire network is unable to communicate until the ring is restored. The advantages of ring topology are: a. Single cable connection between the devices. b. Short cable connection which causes an increase in network reliability. c. Can use the optical fiber to increase the speed and to reduce the problem of electrical interference.
The disadvantages of ring topology are: a. Any node failure causes network failure. b. Difficult to diagnose faults. c. Network re-configuration is difficult.
Star Topology Star topology is the most common topology in use today. It is designed with each node (like workstations, printers, laptops, servers etc.) connected directly to a central device called as a network switch. Each workstation has a cable that goes from its network card to a network switch. Groups of data are routed through the network switch and sent to all the attached nodes, thus eventually reaching their destinations.
70 IT For Kids - Book 7 The advantages of star topology are: a. Stations can be easily added to or removed from the LAN. b. All other links stay active even if one link fails to work. c. Easy to find the failure link.
The disadvantages of star topology are: a. The entire network becomes inoperable if the central hub fails to work. b. More cabling is needed as compared to bus or ring topologies. c. If traffic between the workstations is high, an undue burden is placed on the central hub.
Mesh Topology In a mesh network topology, each of the network node, computer and other devices, are interconnected with one another. Every node not only sends its own signals but also relays data from other nodes. This type of topology is very expensive as there are many redundant connections, thus it is not mostly used in computer networks. It is commonly used in wireless networks.
The advantages of mesh topology are: a. Stability for single application servers. The redundant connection make the mesh network very reliable, even in a high volume traffic situation. b. If one device fails, then with the multiple connection, data will still be sent to its destination. c. Since each of the devices have it own dedicated line, only the device the data is sent to can view the data.
The disadvantages of mesh topology are: a. The amount of cable needed for mesh topology exceeds the amount of any other topology. b. Require many input/output ports which could be really expensive.
IT For Kids - Book 7 71 Internet Internet stands for International Network. It is a means of connecting a computer to any other computer anywhere in the world via dedicated routers and servers. It is also called a “network of networks” as it is made up of various computer networks connected together. It is the largest computer network in the world. The major uses provided by the Internet are listed below: a. Exchange messages using e-mail (Electronic mail) b. Transfer files as well as software c. Browse through information on any topic on web d. Communicate in real time (chat) with others connected to the Internet e. Search databases of government, individuals and organizations f. Read news available from leading news groups g. Send or receive animation and picture files from distant places h. Set up a site with information about your company’s products and services.
Birth of Internet The Internet was originally designed in 1969 as a defence network termed ARPANET (Advanced Research Project Agency). This system provided a series of computer communication links among defence contracted research institution, i.e., universities and military facilities. This developed into a communication link primarily among large universities. In 1982, ARPA established some standards governing the transfer of data between computers in order to improve the speed and reliability of this data transfer. These standards are called protocols and those developed by ARPA were called the Transmission Control Protocol (TCP) and the Internet Protocol (IP). In 1896, the National Science Foundation of America created five super-computing centres linked together over a network, NSFNET, which allowed researchers across America to share and access the data. This led to the formation of interconnected networks. In course of time, the network spread throughout the world, giving birth to Internet.
72 IT For Kids - Book 7 World Wide Web The World Wide Web is a system of interlinked hypertext documents on the Internet. It is a network of online content that is formatted in HTML and accessed via HTTP. It is also called the web. It was created in 1989 by the UK physicist Tim Berners-Lee while working at the European Particle Physics Laboratory (called CERN after its French initials Conseil Europeen de Reserches Nucleaires) in Switzerland, as an easier way to access information scattered across the Internet. It uses the following components:
Components Description
Website A website is a location on the World Wide Web that stores information about a particular topic or company. A website usually consists of a number of web pages. Every website has a unique address. Some popular web sites are www.yahoo.com.and www.google.com.
Web Page A web page refers to a single page of a website.
Web Server A web server is a powerful computer on the World Wide Web that holds one or more websites.
Web Browser A web browser is a software that provides access to the World Wide Web and allows you to view web pages on your computer. Two popular web browsers are Internet Explorer and Netscape Navigator.
Hyperlinks Hyperlinks are words or images that appear (underlined and blue in colour) on web pages. They represent websites. When a mouse is paused over a hyperlink, the mouse pointer turns into a finger pointing to the hyperlink. If the left mouse button is then clicked over the hyperlink, the website represented by the hyperlink is displayed.
Uniform Resource Uniform Resource Locator or URL is a term used to refer to the specific manner of specifying the address of a website. Examples of URL are http://www.yahoo. com and http://www.onlinekhabar.com.
IT For Kids - Book 7 73 Search engine The world wide web stores amount of information on an amazing variety of topic in hundreds of million of pages. Finding information from this huge source is extremely difficult. The information we need is often stored in different names in different sites. Therefore, a special site called a search engine is used to help people find information stored on various sites. Each of these search engines has its own abilities and features but they all help to minimize the time required to find information.
Steps To use a Search Engine
1. Open the required search engine (www.google.com.np). Enter it in the address bar of the web browser and press Enter key or click on the Go button.
1 4 5
6
2. Select the Web link if you want to search the Web for information in all forms (text, pictures, audio, video, etc.) 3. Select the Image link if you want to search the web for images only. 4. Enter your search term in the search box. 5. Click on the Search button. The search engine will take a while to do the required search and list the search results in the form of web pages. 6. You will obtain the search results in the form of web pages made of hyperlinks. You can click on a hyperlink to open a website and see if it contains the information required by you. 7. Click on Next to go to the next page containing search results.
Connect to the Internet and search information on the latest news in Nepal.
74 IT For Kids - Book 7 E-Mail Electronic Mail is the transmission of messages over communications networks. The messages can be notes entered from the keyboard or electronic files stored on disk. Most mainframes, minicomputers, and computer networks have an e-mail system. Companies that are fully computerized make extensive use of e-mail because it is fast, flexible, and reliable.. The most popular web-based email services are www.hotmail.com, www.yahoo.com and www.gmail.com.
Understanding E-Mail Address An email address is the name for an electronic postbox that can receive (and send) email messages on a network. A complete e-mail address is made up of two parts-the username and the host name. The first part identifies the user’s name to whom the mail is to be sent and the second part represents the Fully Qualified Domain Name of the server or host on which the user has an account. These two parts are separated by a ‘@’ symbol. [email protected] is an example of email address.
Creating E-Mail account There are many free electronic mail services available on the Internet. The free electronic mail lets you access your e-mail from any system with a browser and an Internet connection. Some of the free electronic mail providers are HOTMAIL (www.hotmail.com), YAHOO (www.yahoo.com) and GOOGLE (www.gmail. com).
Steps Create an E-Mail account
1. Connect to the Internet. 2. Open any Web browser. A home page will appear on the screen. 3. Type www.gmail.com in the Address bar and press the Enter key. The home page of gmail will appear on the screen. 4. Click the “Sign Up for Gmail” link in the bottom right of the screen. 5. Fill in the appropriate boxes: “First Name”, “Last Name” and “Desired Login Name”. 6. Choose and confirm a password. 7. Fill out the remainder of the form with a security question (which will help you if you forget your password), a secondary email (if you have one), location and word verification. 8. Click on the button marked “I accept. Create My Account”.
IT For Kids - Book 7 75 Composing and Sending an E-Mail There are many free electronic mail services available on the Internet. The free electronic mail lets you access your e-mail from any system with a browser and an Internet connection
Steps Create an E-Mail account
1. Open your gmail account by entering your Username, Password and then click on the Sign in button. 2. Click on the Compose Mail link to open the compose mail window.
Attach Files to Email Messages You can also send pictures, photographs, text files and voice messages as attachments with your mail.
Steps Create an E-Mail account
1. Click Attach, and then click File. 2. The Choose file dialog box appears. Locate and select the file that you want to attach, and then click Open. Repeat this step for each file you want to add. 3. The attached file information appears. 4. Now, click on Send. By default a copy of the sent message is stored in Sent folder.
76 IT For Kids - Book 7 Computer Network A group of two or more computing devices connected via a form of communication links. LAN A computer network that spans a relatively small area. Client-Server network A type of network that is designed for end-users, called clients, to access resources from a central computer called a server. Peer-to-Peer network A group of computers that functions both as a
Word Help Word client and as a server. Network topology The geometrical arrangement of computer resources, remote device, communication facilities. Web server A powerful computer on the World Wide Web that holds one or more websites.
1. A computer network is a group of two or more computing devices connected via a form of communication links. 2. Computer network facilitates the users to share limited and expensive resources among a number of computing devices. 3. The protocols specify the rules, procedures and conventions for communication and data transfer over the network. 4. Local Area Network (LAN) is a computer network that spans a relatively small area. 5. Metropolitan Area Network is a computer network that usually spans a city or a large campus. 6. Centralized computer network is a type of network where all users connect to a central server, which is the acting agent for all communication. 7. A peer-to-peer network is a group of computers that functions both as a client and as a server. 8. In a ring topology, all computers are connected via a cable that loops Points for Review Points in a ring or circle. 9. Star topology is the most common topology in use today. It is designed with each node (like workstations, printers, laptops, servers etc.) connected directly to a central device called as a network switch. 10. The means through which data is transferred from one place to another is called transmission or communication media.
IT For Kids - Book 7 77 Chapter Review
Key Term Quiz
Answer the following questions by filling in the blanks(s). a. ______is a computer network that consists of a computer network at a single site, typically an individual office building. b. ______is a computer network that interconnects users with computer resources in a geographic area. c. The Internet was originally designed in ______as a defence network termed ARPANET (Advanced Research Project Agency). d. A ______refers to a single page of a website. e. ______is used to help people find information stored on various sites.
True or False
State whether the following statements are true or false. a. Local Area Network is a computer network that consists of a computer network at a single site, typically an individual office building. b. MAN is a computer network that spans a large geographic area. c. ARPANET stands for Advanced Research Project Agency Network. d. A web server is a powerful computer on the World Wide Web that holds one or more websites. e. Hyperlink is a term used to refer to the specific manner of specifying the address of a website.
Technical Terms Write the technical term for the following statements. a. A computer network that interconnects users with computer resources in a geographic area. b. A means of connecting a computer to any other computer anywhere in the world via dedicated routers and servers. c. A location on the World Wide Web that stores information about a particular topic or company.
78 IT For Kids - Book 7 d. A software that provides access to the World Wide Web and allows you to view web pages on your computer. e. The transmission of messages over communications networks.
Matching
Match the following. LAN A group of two or more computing devices connected via a form of communication links. Computer Network A computer network that spans a relatively small area. Internet A computer network that interconnects users with computer resources in a geographic area. MAN A computer network that spans a large geographic area such as a city, country, or even intercontinental distances, using a communication channel. WAN A means of connecting a computer to any other computer anywhere in the world via dedicated routers and servers. Multiple Choice
Circle the word or phrase that best completes each statement. a. Computers on a network are called______. i. Server ii. Nodes iii. Both (i) and (ii) iv. Only (ii) b. ______is a computer network that interconnects users with computer resources in a geographic area. i. LAN ii. MAN iii. WAN iv. All of the above c. In______, the National Science Foundation of America created five super-computing centres linked together over a network, NSFNET, which allowed researchers across America to share access to data. i. 1896 ii. 1996 iii. 1986 iv. None of the above
IT For Kids - Book 7 79 d. ______are words or images that appear (underlined and blue in colour) on web pages. i. URL ii. Hyperlinks iii. None of the above iv. All of the above e. A complete e-mail address is made up of two parts-the______and the host name. i. User name and host name ii. User name and password iii. None of the above iv. All of the above
Review Questions Answer the following questions. a. What is a computer network? b. What are the advantages of computer network? c. What are the components of a computer network? d. What is Local Area Network? How does it differ from Wide Area Network? e. What is LAN topology? Name the basic types of topology. f. What is bus topology? What are the advantages and disadvantages of bus topology? g. What is star topology? Draw a neat diagram of star topology. h. What is the Internet? What are the major uses of the Internet? i. Explain in short the history of the Internet. j. What is World Wide Web? What are the components of World Wide Web? k. Define the following terms: i. Website ii. Web Browser iii. Uniform Resource Locator l. What is E-Mail? What is e-mail made up of?
Discussion Question
As directed by your instructor, discuss the following questions in class or groups. Discuss key topologies used to form a network. Explain in short how wireless network topologies work.
80 IT For Kids - Book 7 8 Computer Viruses Chapter Chapter
Overview
Computer virus pose a considerable problem for users of personal computers. It is well known that the virus problem is most severe problems for users of personal computer. A computer virus is a computer program that is designed to spread from host to host and has the ability to replicate itself. Computer virus attaches itself to files stored on removable disk, e-mail attachments and hard disks. A file containing a virus is called infected file. If this file is copied to a computer, virus is also copied to the computer. It has the capacity to corrupt or to delete data on your computer.
How Does a Virus Spread? A computer virus is a software program designed to replicate itself and spread to other machines. There are numerous ways that computer viruses are spread from one computer to another. a. Sharing and transferring files on flash drives is a very common practice today. b. Computer virus can spread if the users opens and downloads an e-mail attachment. c. Computer virus can spread if an infected computer is connected to a network. d. Computer virus can spread if user installs pirated software that contains a virus. e. Rogue programs such as fake anti-virus and security utilities are one of the most frequent ways that online users acquire computer viruses today.
IT For Kids - Book 7 81 Types of Computer Viruses There are many kinds of viruses. Viruses come in a wide variety. The level of destructiveness of viruses varies widely. There are different types of viruses due to the different mode of infection. Some of the most common types of viruses are:
Boot Sector Viruses Boot sector virus is a type of computer virus that infects a storage device’s master boot record (MBR). During startup, the virus is loaded into memory. Once in memory, the virus will infect any non-infected disks accessed by the system. An example of a boot sector virus is Parity Boot.
File Infecting Viruses File-infecting virus is a type of virus that infects executable files by inserting their code into some part of the original file so that the malicious code can be executed when the file is accessed. It overwrites the original file entirely, replacing it with the malicious code. Win32.Sality.BK is a popular file-infecting virus.
Macro Viruses Macro virus is defined as a computer virus written in the same macro language used for software applications, such as word processors. Microsoft Word and Excel are two examples of applications that feature powerful macro languages, which are embedded in documents so they run automatically when the documents are open. The examples of macro viruses are W97M.Melissa, WM.NiceDay and W97M.Groov.
Polymorphic Viruses Polymorphic virus is a type of virus that can change its appearance with every infection. It is a self-encrypted virus designed to avoid detection by an antivirus. Antivirus software must perform algorithm scanning to detect these viruses. The examples of polymorphic viruses are Involuntary, Stimulate, Cascade, Phoenix, Evil and Proud.
Stealth Viruses Stealth virus is a hidden computer virus that attacks operating system processes and averts typical anti-virus or anti-malware scans. Stealth viruses hide in files, partitions and boot sectors and are adept at deliberately avoiding detection. The examples of stealth viruses are Frodo, Joshi and Whale.
82 IT For Kids - Book 7 Symptoms of a Computer Virus Some of the primary symptoms of virus attack are listed below: a. A computer program disappears from its memory, especially if there is no known removal of the program. b. Unfamiliar music or sounds unexpectedly starts playing through the speakers. c. Icons appear on the desktop unrelated to any programs that are currently being installed, or new icons seem to appear when no software has been installed. d. Unusual error messages will pop up. e. Items are not printing correctly. f. Disk drives or disks become inaccessible. g. An application or applications are not working correctly. h. The computer restarts continuously. i. The computer locks up frequently or stops responding. j. The computer seems to be losing processing speed.
Protecting Your Computer Against Viruses Virus infection on your computer may cause a very serious damage and even loss on your business. Some of the ways to protect computers against viruses are as follows: a. Always use a virus scanner and always remove viruses and worms if you find them. Keep up to date with virus detection files. b. The automatic virus monitors should be running constantly on your system to ensure that no infected files are transferred to your hard disk over the network. c. Always scan files downloaded from the Internet or transferred over the network before executing them on your machine. d. Scan all e-mail attachments before executing them on your machine. e. Ensure a personal firewall program is configured. f. Scan your hard disk at least twice a month for viruses.
Research and Report
Write a brief paragraph describing how virus scanner protects your computer system.
IT For Kids - Book 7 83 Anti-Virus Software Anti-virus software is a software utility that detects, prevents, and removes viruses, worms, and other malware from a computer. It will scan downloaded files as well as your entire computer system in order to detect the presence of an infection. Some popular antivirus software available are: Norton AntiVirus, McAfee VirusScan and SmartDog. Some of the functions that an antivirus performs are: a. Antivirus programs offer real-time protection. This means that the antivirus program protects your computer from incoming threats. b. Antivirus programs offer threat detection. This means that the antivirus program can scan your entire computer in search of viruses. c. Antivirus programs offer automatic updates. Automatic updating is important because an out of date antivirus program will not be able to detect the newest viruses. d. Antivirus programs have the ability to alert you when a program is trying to access your computer. Many of the programs that attempt to access your computer are harmless or downloaded voluntarily and thus the antivirus program will give you the option of allowing or preventing the access. e. Depending on the antivirus software, it may perform a host of additional functions. These may include outbound e-mail protection, instant messaging protection, identity theft protection and pop-up blocking. f. Some antivirus software include quarantine and blocking features.
Know More Norton Antivirus Norton Antivirus is a product of Symantec Corporation that contains important information about preventing viruses from attacking the system, types of viruses and their attack method. Norton Antivirus, when loaded onto a computer system, checks the following areas for viruses: a. Boot records b. Programs at the time you use them c. All local hard drives d. Files downloaded from the Internet e. Floppy disks when in use
84 IT For Kids - Book 7 Computer virus A software program designed to replicate itself and spread to other machines. Boot sector virus A type of virus that infects computer systems by copying code either to the boot sector on a floppy disk or the partition table on a hard disk. File-infecting virus A type of virus that infects executable files by inserting their code into some part of the original file so that the malicious code can be executed when the file is accessed
Word Help Word Macro virus A computer virus written in the same macro language used for software applications, such as word processors. Antivirus software A software utility that detects, prevents, and removes viruses, worms, and other malware from a computer.
1. A computer virus is a computer program that is designed to spread from host to host and has the ability to replicate itself. 2. Boot sector virus is a type of computer virus that infects a storage device’s master boot record (MBR). 3. File-infecting virus is a type of virus that infects executable files by inserting their code into some part of the original file so that the malicious code can be executed when the file is accessed. 4. Macro virus is defined as “a computer virus written in the same macro language used for software applications, such as word processors.” 5. Stealth virus is a hidden computer virus that attacks operating system processes and averts typical anti-virus or anti-malware scans. 6. Polymorphic virus is a type of virus that can change its appearance with every infection. 7. Stealth virus is a hidden computer virus that attacks operating system processes and averts typical anti-virus or anti-malware scans. Points for Review Points 8. Anti-virus software is a software utility that detects, prevents, and removes viruses, worms, and other malware from a computer. 9. Antivirus programs offer real-time protection. This means that the antivirus program protects your computer from incoming threats. 10. Antivirus programs have the ability to alert you when a program is trying to access your computer.
IT For Kids - Book 7 85 Chapter Review
Key Term Quiz
Answer the following questions by filling in the blanks(s). a. A______is a computer program that is designed to spread from host to host and has the ability to replicate itself. b. ______is a type of computer virus that infects a storage device’s master boot record (MBR). c. ______is defined as “a computer virus written in the same macro language used for software applications, such as word processors.” d. ______is a hidden computer virus that attacks operating system processes and averts typical anti-virus or anti-malware scans. e. ______software is a software utility that detects, prevents, and removes viruses, worms, and other malware from a computer.
True or False
State whether the following statements are true or false. a. Computer virus can spread if the users opens and downloads an e-mail attachment. b. Boot sector virus is a type of computer virus that infects a storage device’s master boot record (MBR). c. Polymorphic virus is a hidden computer virus that attacks operating system processes and averts typical anti-virus or anti-malware scans. d. Disk drives or disks become inaccessible is the primary symptom of virus attack. e. Anti-virus software is a software utility that detects, prevents, and removes viruses, worms, and other malware from a computer.
Technical Terms Write the technical term for the following statements. a. A small software program that can spread from one computer system to another and cause interferences with computer operations. b. A type of virus that infects the boot sector of removable disks or the Master Boot Record (MBR) of hard disks. c. A type of computer virus that infects the macros within a document or template. 86 IT For Kids - Book 7 d. A hidden computer virus that attacks operating system processes and averts typical anti-virus or anti-malware scans. e. The programs which can detect, prevent and clean up computer viruses which may attempt to infect your computer system.
Matching Match the following. Boot sector virus A software program designed to replicate itself and spread to other machines. Computer virus A type of virus that infects computer systems by copying code either to the boot sector on a floppy disk or the partition table on a hard disk. Macro virus A type of virus that infects executable files by inserting their code into some part of the original file so that the malicious code can be executed when the file is accessed Antivirus software A computer virus written in the same macro language used for software applications, such as word processors. File-infecting virus A software utility that detects, prevents, and removes viruses, worms, and other malware from a computer. Review Questions Answer the following. a. What is a computer virus? b. Explain in short how a computer virus spreads. c. What is boot sector virus? Give examples. d. What is a file infecting virus? Give examples. e. List some symptoms of a computer virus infection. f. List some precautions that must be observed to avoid computer virus infection. Discussion Question As directed by your instructor, discuss the following questions in class or groups. Explain the features of latest antivirus software.
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