Lalitpur, Nepal, Tel: 977-1-5529899 E-mail: [email protected] www.greenbooks.com.np Computer Green Approved by Government of Nepal, Ministry of Education, Curriculum Development Centre, Sanothimi, Bhaktapur as an additional material 8 Editor Reg Bahadur Bhandari Author Prabhu Prasad Sah
Publisher: Green Books Copyright: Author (2074 BS) Printed in Nepal Layout The Focus Computer [email protected] Edition First : B.S. 2074 (2017 AD) Reprint : B.S. 2075 (2018 AD) Revised : B.S. 2076 (2019 AD) Revised : B.S. 2077 (2020 AD) Computer Green 9
Computer has become an integral part of human life. Computer is the greatest invention man has ever made. There are hardly any fields on this earth where computers have not been used. So, it has become a necessity for every individual to be computer literate. So, computer studies has been incorporated in curriculum in our country too. Green Computer series has been designed with a vision that it would help students address their general needs of word-processing and simple database management and also to orient their minds to IT to be able to contribute in the future. This series can be a great tutorial for novices who are really interested to learn the basics of computer. All our efforts have been put forth to make this series descriptive in order to make the contents understandable and communicate instructions easily. We have tried to use simple English for the convenience and easy understanding of instructions both in theory as well as in practical lessons. Varieties of theory based exercises and relevant lab sessions have been included in order to give concepts on different topics and evaluate students’ understanding. We would like to express our sincere gratitude to Green Books, Focus Computer Team, colleagues, friends and well wishers without whom, this series wouldn’t have taken is shape. We believe that this series is free of errors, yet there can be some slips. So, we would like to welcome from all our readers students, teachers, individuals and institutions valuable suggestions and feedback for revision in the upcoming editions. Finally, we are thankful to our parents for making us capable of contributing a little to the society and the country. Author Preface
Content 1. History of Computer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Computer Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 3. Types of Computer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 4. Computer Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 5. Types of Operating System . . . . . . . . . . . . . . . . . . . . . . . . 34 6. Number System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 7. Advanced Features of Microsoft Word . . . . . . . . . . . . . . 50 8. More on Spreadsheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 9. Advance Features of PowerPoint . . . . . . . . . . . . . . . . . . 106 10. Concept of ICT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122 11. Cyber Law and Ethics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127 12. Computer Virus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132 13. Data Communication and Computer Network . . . . . . 138 14. Introduction to Internet and E-mail . . . . . . . . . . . . . . . . 151 15. Hyper Text Markup Language(HTML) . . . . . . . . . . . . . 161 16. Multimedia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211 17. Graphics Application (Adobe Photoshop) . . . . . . . . . . . 219 18. Program Development Life Cycle (PDLC) . . . . . . . . . . . 236 19. Algorithm and Flow Chart . . . . . . . . . . . . . . . . . . . . . . . . 241 20. Fundamental of QBASIC . . . . . . . . . . . . . . . . . . . . . . . . . 249 21. QBASIC Statements and Library Functions . . . . . . . . . 263 22. Looping in Qbasic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282
GREEN Computer Book-8 5 1 History of Computer Introduction Humans have always needed to perform arithmetic operation like counting and adding. During the pre-historic period, they counted either on their fingers or by scratching marks on the bones and then with the help of stones, pebbles and beads. The word ‘computing’ means ‘an act of calculating’. The evolution of computers has passed through a number of stages before reaching the present state of development. In fact, the history of computers comprises a gradual development from a simple abacus to the electronic computers we use today. a. Abacus The abacus was created by the Chinese about 3000 years ago as the first mechanical aid to do calculations. Calculations are performed by manipulating the beads. It is a rectangular box, divided into two parts by the mid bar. The upper part is called “heaven” which consists of two beads and each bead is equal to five and the lower part is called “earth” and consists of five beads and each bead is equal to one. b. Napier’s Bone Napier's Bone was invented by John Napier in 1614 AD. He was a Scottish mathematician born in 1550 and died in 1617 AD. Multiplication tables were inscribed on strips of wood or bone. It was possible to perform calculations with two numbers. It is mainly used for multiplication.
6 GREEN Computer Book-8 d. Pascaline Pascaline was developed by Blaise Pascal in 1642 to help his father in his tax works. It contains eight dials, gears and wheels. It was capable of performing additions and subtractions up to 8 digits. It could add and subtract by the movement of wheels and could not be used for division and multiplication. c. Slide Rule Slide Rule was invented by William Oughtred, an English mathematician in 1620. It is an analog device that uses the principle of logarithms. It can perform simple multiplication and division problems. It consists of two graduated scales, devised in such a way that suitable alignment of one against other makes it possible to obtain products, quotients, etc. John Napier of Merchiston also signed as Neper, Nepair; nicknamed Marvellous Merchiston) was a Scottish landowner known as a mathematician, physicist, and astronomer. John Napier is best known as the inventor of logarithms. He also invented the so-called "Napier's bones" and made common the use of the decimal point in arithmetic and mathematics. William Oughtred was an English mathematician and Anglican minister. After John Napier invented logarithms and Edmund Gunter created the logarithmic scales (lines, or rules) upon which slide rules are based, it was Oughtred who first used two such scales sliding by one another to perform direct multiplication and division; and he is credited as the inventor of the slide rule in 1622. Oughtred also introduced the "×" symbol for multiplication as well as the abbreviations "sin" and "cos" for the sine and cosine functions.
GREEN Computer Book-8 7 e. Stepped Reckoner Stepped Reckoner was developed by Gottfried Wilhelm Von Leibniz, a German mathematician and philosopher in 1694. It could evaluate square roots by a series of stepped additions. The centerpiece of this machine is its stepped drum gear design. It could perform all four of the basic arithmetic functions – addition, subtraction, multiplication and division. In 1642, while still a teenager, Blaise Pascal started some pioneering work on calculating machines. After three years of effort and 50 prototypes, he built 20 finished machines (called Pascal's calculators and later Pascalines) over the following 10 years, of the first two inventors of the mechanical calculator establishing him as one. Gottfried Wilhelm (von) Leibniz was a German polymath and philosopher who developed differential and integral calculus. Leibniz's notation has been widely used ever since it was published. While working on adding automatic multiplication and division to Pascal's calculator, he was the first to describe a pinwheel calculator in 1685 and invented the Leibniz wheel, used in the arithmometer, the first massproduced mechanical calculator. He also refined the binary number system, which is the foundation of virtually all digital computers. f. Difference Engine Difference Engine was designed by Charles Babbage, an English mathematician, in 1822. It could solve equations. This project could not be completed due to lack of funds. It was housed in the Science Museum, London and is still in perfect working order.
8 GREEN Computer Book-8 g. Analytical Engine Analytical Engine was developed by Charles Babbage in 1833. It had a ‘store’ for storing data and intermediate results. It had an output device to produce printed results. It had a unit for calculation called ‘mill’. All the modern computers are based on the working principle of analytical engine (input-process-output). Charles Babbage is known as the ‘Father of Modern Computer’ as his invention of Analytical Engine had more of the characteristics of modern computers. h. Hollerith Tabulator Tabulator was developed by an American, Dr. Herman Hollerith, in 1887. It used punch cards for input, output and instructions. This machine was used by American Department of Census to compile the 1890 census. • In 1890, punch cards were used by Herman Hollerith to automate Census • Concept of programming the machine to perform different tasks with punch cards was from Babbage. • Punch cards based on Joseph Marie Jacquard’s device to automate weaving looms. • In 1896, he founded the tabulating machine company which was renamed as IBM (International Business Machine).
GREEN Computer Book-8 9 Lady Augusta Ada Lovelace An English mathematician (daughter of English Poet Lord Byron) carried forward the work of Charles Babbage. She developed programs for performing mathematical calculation on the Analytical Engine. She was the first computer programmer. One programming language ‘Ada’ was named after her. John Von Neumann He was the doctorate in mathematics from the University of Budapest on set theory. He designed the EDVAC with team of J.P. Eckert and J.W. Mauchly. He introduced the concept of having a stored program in memory in 1945. This concept led to the beginning of the first generation of computers. Electro-Mechanical Computers Mark-I • Mark - I was designed by Howard Aiken, a Harvard engineer in 1937. It was 51 ft. long, 8 ft. tall and 3 ft. wide having 18000 vacuum tubes. It was the first automatic electromechanical computer. It used instructions stored in paper tapes and punch cards. It consisted of 7 lakh 50 thousand parts.
10 GREEN Computer Book-8 ABC (Atanasoff-Berry Computer) • ABC was the first electromechanical digital computer. Built in 1937-1942 at Iowa State University by John V. Atanasoff and Clifford Berry. • It introduced the ideas of binary arithmetic and logic circuit. • It used punch cards as secondary storage. Inventor's birth date and death date Inventor's name Birth date Death date John Napier 1550 4-April 1617 William Oughtred 5 March 1574 30 June 1660 Blaise Pascal 1623 1642 Gottfried Wilhelm Von Leibniz 1 July 1646 14 November 1716 Charles Babbage 1792 1871 Herman Hollerith 1869 1926 Lady Augusta Ada 1816 1852 John Von Neumann 1903 1957 Howard Aiken 1900 1973 Electronic Computers ENIAC (Electronic Numerical Integrator and Calculator) • ENIAC was designed by Dr. John W. Mauchly and Dr. J. P. Eckert, completed in 1946. • It was built from 18,000 vacuum tubes and 70,000 resistors. Power consumption – 50,00,000 Kilowatt and floor space – 1,800 square feet. • It could add two numbers in 200 microseconds and multiply two numbers in 2800 microseconds. EDSAC (Electronic Delay Storage Automatic Computer) • EDSAC was designed by Maurice Wilkes at Cambridge University,
GREEN Computer Book-8 11 mathematical laboratory in 1947. • It was the first operational stored-program computer. • It contained 3000 vacuum tubes and operated with 30 kilowatt of power. • It used a mercury delay line storage system. EDVAC (Electronic Discrete Variable Automatic Computer) • Designed by J. Mauchly and J.P. Eckert at Pennsylvania University and was completed in 1950. • It included a stored-program, a central processor and a memory for both data and programs. UNIVAC (Universal Automatic Computer) • Produced by Universal Accounting Company and set up by John Mauchly and J.P. Eckert in 1951. • It consisted of magnetic tape for data input and output. • It was the first general-purpose electronic digital computer designed for commercial use. History of Computer in Nepal • The history of computer in Nepal is relatively new, started from 2018. • In 2018 BS an electronic calculator called "Facit" was used for census. • In 2028 BS (1972 AD) census, IBM 1401 a second generation mainframe computer was used. • In 2031 BS (1975 AD), a center for Electronic Data Processing, later renamed as National Computer Center (NCC),was established for national data processing and computer training. • In 2038 BS ( 1982 AD), ICL 2950/10 a second generation mainframe computer was used for census. • Now-a-days probably each and every institution, business organization, communication center, ticket counter, etc are using computers in Nepal.
12 GREEN Computer Book-8 POINTS TO REMEMBER 1. The abacus was created by the Chinese about 3000 years ago as the first mechanical aid to calculations. 2. Napier’s Bone can perform calculations with two numbers. 3. MARK-I is the first electromechanical computer. 4. The vacuum tube was used in the first generation computers. 5. ABC (Atanasoff-Berry Computer) is the first electromechanical digital computer. 6. William Oughtred also introduced the "×" symbol for multiplication as well as the abbreviations "sin" and "cos" for the sine and cosine functions. 7. Pascaline was capable of performing additions and subtractions up to 8 digits. 8. UNIVAC consisted of magnetic tape for data input and output. 9. EDSAC used a mercury delay line storage system. 10. Lady Augusta Ada developed programs for performing mathematical calculation on the Analytical Engine. Exercise 1. Answer the following questions: a. What is an abacus? Draw a neat and clean figure of an abacus. b. Why is Charles Babbage called the Father of Computer? c. Who is known as the first computer programmer? Why? d. Who developed Napier’s Bone? When was it developed? e. What do you know about Hollerith Tabulating machine? f. Who developed Pascaline and when? What type of calculation could it perform? g. Give a brief history of computer in Nepal? 2. Write down the Full Forms of the following: a. ABC b. UNIVAC c. EDVAC d. EDSAC e. ENIAC
GREEN Computer Book-8 13 3. Write short notes. a. ABC computer b. ENIAC c. Mark-I d. Analytical Engine 4. Match the following: a. MARK-I John V. Atanasoff and Clifford Berry. b. UNIVAC Father of Ccomputer c. Charles Babbage Howard Aiken d. ABC EDVAC e. J. Mauchly and J.P. Eckert first general-purpose electronic digital computer 5. State whether the following statements are ‘True’ or ‘False’. a. The abacus is the first electronic computer. b. It was the first general-purpose electronic digital computer designed for commercial use. c. EDSAC used a mercury delay line storage system. d. Difference Engine was developed by Howard Aiken. e. Napier’s Bone can perform calculations with two numbers. 6. Who developed the following devices and when? Devices Developed by Date of Invention ENIAC EDSAC EDVAC UNIVAC ABC MARK-I ANALYTICAL ENGINE PASCALINE STEPPED RECKONER SLIDE RULE NAPIER’S BONE
14 GREEN Computer Book-8 2 Computer Generation Introduction Initially, the term generation was used to distinguish between varying hardware technologies. But nowadays, generation includes both hardware and software, which together make up an entire computer system. The evolution of modern digital computing took place in five distinct phases known as computer generations, which are classified on the basis of their speed, capacity, reliability, components used, etc. First Generation Computers (1945-1956) Vacuum Tube: It was used as the main component for memory and circuitry for CPU. It was very slow, large in size, and consumed a lot of electrical power. The operating speed was measured in terms of milliseconds. Storage capacity was too small; only 1 to 4Kb. They used machine level programming language. Punch cards, paper tape, and magnetic tape were used as input and output devices. Batch processing operating systems were used. Some of the first Generation Computers are: Mark – I, ENIAC, EDVAC, EDSAC, UNIVAC, etc.
GREEN Computer Book-8 15 The vacuum tube was invented by Lee De Forest in 1907. It is a set of metal electrodes and grids contained in a glass or metal tube. It was formerly used for amplification and switching in electronic circuits, now used in CRT (Cathode Ray Tube). Transistor is short form of transfer resistor. It is a solid state semi-conductor device which can be used for amplification, switching, voltage stabilization, signal modulation, etc. It transfers signals from a low resistance to high resistance. It was invented in 1947 by three Bell Lab scientists John Bardeen, Walter Brattain, and William Shockley. It was used in the second generation computers as major components. Second Generation Computers (1956 – 1963) Transistors replaced vacuum tubes. One transistor consist of thousand vaccum tubes. The size of computer was reduced. It became faster and more reliable than the first generation computers. The operating speed was measured in terms of microseconds. Magnetic tapes were used as secondary storage media. High-level programming languages were also being developed at this time, such as early versions of COBOL and FORTRAN. Some of the second Generation Computers are: LEO Mark III, ATLAC, UNIVAC I, ICL 1901, etc.
16 GREEN Computer Book-8 Third Generation Computers (1964-1971) IC (Integrated Circuits) made the computers smaller, more efficient and more reliable than the previous generation of computers. The operating speed was measured in terms of nanoseconds, so that computers became so fast. In the beginning magnetic core memories were used. Later they were replaced by semiconductor memories (RAM & ROM) There were input and output devices such as keyboard and monitors instead of punch cards in this generation. Due to the use of input and output devices, it was so easy in operation. High level languages (FORTRAN-II TO IV, COBOL, PASCAL PL/1, BASIC, ALGOL -68 etc.) were used during this generation. Some of the third Generation Computers are: IBM 360 Series, ICL 1900 Series, VAX 1/780, etc. An IC is a circuit consisting of a large number of electronic components placed on a single silicon chip by a photolithographic process. Jack Kilby invented it in 1958. IC is used for a variety of devices, including microprocessor, audio and video equipment and automobiles. Fourth Generation Computers – (1971 – Present) Microprocessor/ Large Scale Integrated Circuit (LSIC) and Very Large Scale Integrated Circuit (VLSIC) was the main component that included 5000 transistors. Due to the use of LSIC and VLSIC size was greatly reduced. The operating speed increased beyond picoseconds. Many sophisticated programs for special application were available. Magnetic and optical storage devices with
GREEN Computer Book-8 17 capacity more than 500GB were used as secondary memory. All the Higher level languages like C and C++, DBASE, etc. were used in this generation. Some of the fourth Generation Computers are: Pentium I/II/III/IV, HP 3033, APPLE II, etc. The microprocessor is a computer processor built onto a single piece of silicon, known as a wafer or chip. The first microprocessor is Intel 4004 developed by American Intel Corporation in 1971. Fifth Generation Computers – (Present and Beyond) Major components – ULSI (Ultra Large Scale Integration). The concept of AI (Artificial Intelligence) has been introduced which enables the computers to take decisions on their own. Bio chips and Gallium Arsenide (Ga As) are used as memory devices. Extremely high-speed parallel processing capability. Large use of natural language processing and user friendly. Programming computers for robotics to see, hear and react to other sensory stimuli. More user friendly interfaces with multimedia features. Portable note book computers introduced. Some of the Fifth Generation Computer Projects are: ICOT program in Japan, MCC project in the USA, etc.
18 GREEN Computer Book-8 The future device that will be used in the 5th generation computers, made of large organic molecules and a genetically engineered protein is called “Biochip”. POINTS TO REMEMBER 1. The microprocessor replaced IC in the fourth generation. 2. An IC is a circuit consisting of a large number of electronic components placed on a single silicon chip. 3. The computer generations are classified into five different categories as per the technological advancements and major components used for processing over different periods of time. 4. Transistor was invented in 1947 at Bell Labs by Robert Noyce and Jack Kilby. 5. The Third Generation of Computers used IC as their major components which could do the functions of millions of transistors. 6. ICs are made up of silicon, a semiconductor material. 7. The Fifth Generation of Computers are believed to have the features like human brains which is known as AI (Artificial Intelligence). Exercise 1. Answer the following questions: a. What is Abacus? Draw a neat and clean figure of Abacus. b. What is computer generation? c. What are the features of the fifth generation of computers? d. Write the differences between the first generation and the second generation of computers. e. Who developed IC and when? f. What are the features of the fourth generation computers?
GREEN Computer Book-8 19 2. Write down the Full Forms of the following: a. IC b. AI c. ULSI d. LSIC e. Ga As 3. State whether the following statements are ‘True’ or ‘False’. a. The IC was used in the first generation computers. b. A transistor is a circuit consisting of a large number of electronic components. c. Our PC is the fourth generation computer. d. The first generation computers were very small. e. If replaced VLSIC in fourth generation. f. Intel 4004 was developed by American Intel Corporation 1971. g. ICL 1900 series was developed in second generation. h. Microprocessor is a computer processor build onto a single piece of silicon. 4. Match the following words: a. VLSIC Jack Kilby b. Vacuum tube John Bardeen, Walter Brattain, and William Shockley c. Transistor fourth generation computer d. Biochip Lee De Forest e. IC Fifth generation 5. Fill up the table with the appropriate information. Generations Period Main component Computers developed 1st generation 2nd generation 3rd generation 4th generation 5th generation
20 GREEN Computer Book-8 3 Types of Computer Introduction The computer on the desk in your computer lab is a microcomputer. It is a small, powerful piece of equipment. Even so, the power of a microcomputer is not enough for most large organizations. Computers can be used in different sectors like school, hospital, offices, resource centers, music, movies, etc. Computers used in different sectors may not be of the same types. They may differ in processing speed, storage capacity, size and nature of tasks that they can perform. A computer can be as big as an entire room or as small as a microcontroller found in mobiles and embedded systems. Computers may be special purpose computer and general purpose computer. Special purpose computers are designed to perform specific tasks and general purpose computers are versatile, designed to perform various tasks. Computers can be divided into different categories on the basis of size and work. On the basis of work There are three types of computers on the basis of work. They are: 1. Analog computer 2. Digital computer 3. Hybrid computer 1. Analog computer: An analog computer is a computing device that works on continuous range of values. It gives approximate results since it deals with quantities that change
GREEN Computer Book-8 21 continuously. It generally deals with physical variables such as voltage, pressure, temperature, speed, etc. ECG (Electro Cardio Graph) is an example of an analog computer. 2. Digital computer: Our PC is a digital computer which operates on discrete data. Its operation is based on binary system. i.e. 0 and 1 digits. Digital Computers can give the results with more accuracy and at a faster pcae. They are able to save data for future use also. 3. Hybrid computer: A hybrid computing system is a combination of desirable features of analog and digital computers. It is mostly used for automated and complex operations such as ultra sound and equipment of ICU (Intensive Core Unit) in hospitals. (ECG) Electrocardiogram, Halter Monitoring machine, etc. are examples of hybrid computer. On the basis of size: There are four types of computers on the basis of size and speed and these all are digital computers. 1. Micro computers 2. Mini computers 3. Mainframe computers 4. Super computers
22 GREEN Computer Book-8 Workstations are also single-user computers like PC but are typically linked together to form a local-area network, although they can also be used as stand-alone systems. Workstations generally come with a large, high-resolution graphics screen, large amount of RAM, inbuilt network support, and a graphical user interface. 1. Micro computers: The invention of the microprocessor (single chip CPU) gave birth to micro computers. Official and household computers are micro computers. Micro computers are also known as personal computers. They are small in size and light in weight. Some of the micro computers can be held on the palm and on the lap. They are called palmtop and laptop computers. Personal computers are categorized as: Desktop computers Desktop computers are designed for use at a desk or table. They are typically larger and more powerful than other types of personal computers. Tower PCs: Tower PCS are those microcomputers in which the case sits as a "tower," often on the floor beside a desk, thus freeing up the desk surface space. Laptops and Notebooks Laptops and Notebooks are also called notebook computers. They are light weight portable computers with built-in monitor, keyboard, hard-disk drive, battery, and AC adapter that can be plugged into an electrical outlet. You can put a laptop on your lap and work.
GREEN Computer Book-8 23 Personal digital assistants (PDAs) PDAs are also called handheld computers or palmtops combine personal organization toolsschedule planners, address books, to-do lists, etc. Some are able to send e-mails and faxes. Some PDAs have touch-sensitive screens. Some also connect to desktop computers for sending or receiving information. Tablet PCs Tablet PCs are mobile PCs that combine features of laptops and handheld computers. Like laptops, they're powerful and have a built-in screen. Like handheld computers, they allow you to write notes or draw pictures on the screen, usually with a tablet pen instead of a stylus. They can also convert your handwriting into typed text. Some Tablet PCs are “convertibles” with a screen that swivels and unfolds to reveal a keyboard underneath. Smart phones Smart phones are mobile phones that have some of the same capabilities as a computer. You can use a smart phone to make telephone calls, access the Internet, organize contact information, send e-mails and text messages, play games, and take pictures. Smart phones usually have a virtual keyboard and a large screen. 2. Mini computers: Mini computers are the medium sized computers which are larger than micro computers and smaller than mainframe computers. They have larger storage capacity and higher speed than micro computers. Minicomputers may contain one or more processors, support multiprocessing and tasking that can support up to 200 users simultaneously, and are generally resilient to high workloads. Some of the Mini Computers are: IBM AS/400, IBM SYSTEM 360, HP 3000, PRIME 9755.
24 GREEN Computer Book-8 3. Mainframe computers: A very large and expensive computer capable of supporting hundreds, or even thousands, of users simultaneously is mainframe computers. Their performance speed and storage capacity is higher than the mini computers. Some of the obvious customers are banks, airlines and railway reservation systems, aerospace companies doing complex aircraft design, etc. Some of the Mainframe Computers are - IBM S/390, Amdahl 580, Control Data Cyber 176. 4. Super Computers: Super computer are the most powerful and expensive computers. They are very high speed computers. They are employed for specialized applications that require immense amounts of mathematical calculations. They are used in the areas like weather forecasting, automobile designing, aircraft launching, bomb testing, etc. Some of the super computers are: Cray-1, Cray-2, Control Data Cyber 205, ETA, etc. POINTS TO REMEMBER 1. Micro computers are also known as personal computers. 2. An analog computer is a computing device that works on continuous range of values. 3. Our PC is a digital computer which operates on discrete data. 4. A hybrid computer is the fusion of analog and digital computers. 5. A super computer is the fastest computer used in scientific research. 6. Minicomputers may contain one or more processors, support multiprocessing and tasking that can support up to 200 users simultaneously. 7. A laptop is also called notebook computer. 8. The computers on the basis of size are digital computers.
GREEN Computer Book-8 25 Exercise 1. Answer the following questions: a. Write any two differences between analog computers and digital computers. b. What do you mean by a hybrid computer? Give some examples. c. What is a super computer? Where is it used? d. List out the computers on the basis of size. e. What is a micro computer? List out the types of microcomputers. f. Write differences between minicomputers and mainframe computers. 2. Write short notes on : a. Desktop b. Tablet c. PDA d. Workstation 3. State whether these statements are 'True' or 'False': a. Personal computers are also called digital computers. b. A desktop computer can be put into the lap and work. c. Smart phones are mobile phones that have some of the same capabilities as a computer. d. Super computers are used in scientific research. e. Analog computers represent the data in discrete variable. 4. Match the following: a. Laptop combine features of laptops and handheld computers b. Analog computer middle size computer c Workstation works on continuous flow of data d. Minicomputer small portable computer e. Tablet built in network support 5. Fill in the blanks: a. Temperature, voltage, etc can be measured by............................ computer. b. ............................ computers generally connected in network. c. ............................ can support up to thousand users simultaneously. d. ............................ used in research and whether forecast.
26 GREEN Computer Book-8 e. Hybrid computers use both .......................and ..................... 6. Choose the best answer: a. A ..............computer is used in scientific research. i. Hybrid computer ii. Analog computer iii. Super computer b. Computer used in server is called .............. i. analog computer ii. super computer iii. minicomputer c. A computer that is mostly used in a hospital.............. i. analog computer ii. hybrid computer iii. digital computer d. A digital computer displays the output as.............. i. discrete data ii. continuous data iii. none e. An analog computer displays the output as.............. i. discrete data ii. continuous data iii. none 7. Tech terms. a. The most powerful and expensive compuer used in weather forcastinf and aircraft launching. b. A large and expensive computer capable of supporting hundreds or even thoussands of users simultaneously. c. The medium size computer capable of of supporting upto 200 users simultaneously. d. The light weight, portable computer with built in monitor, keyboard, hard disk, drive battery and AC adapter. e. The single user computer typically linked together to form a local area network. f. The computer which operates on discrete data.
GREEN Computer Book-8 27 4 Computer Software Introduction Software is a set of programs, which is designed to perform a well-defined functions. A program is a sequence of instructions written to solve a particular problem. Software is the soul of a computer. Without software, a computer cannot do anything. Software instructs hardware parts to perform a certain task. Basically, there are two types of software: • System Software • Application Software Tailored Software Packaged Software Utility Software Device Driver Language Processor Operating Software Application Software System Software Software Software is an intangible product and moreover it is a process. Know More System Software The system software is a collection of programs designed to operate, control, and extend the processing capabilities of a computer itself. Computer manufacturer prepare various kinds of system software. These software products comprise of programs written in low-level languages which interact with the hardware at a very basic level. System software serves as the interface between hardware and the end users.
28 GREEN Computer Book-8 Features of system software are as follows: • Close to system hardware. • Fast in loading and processing. • Difficult to design and develop. • Difficult to understand. • Less interactive. • Generally written in low-level language. Types of system software: 1. Operating system software 2. Language processor 3. Device driver 4. Utility software Operating system: The software which controls and coordinates overall functions of a computer is called operating system software. An operating system is a program that acts as an interface between the software and the computer hardware. It manages overall resources and operations of a computer. It helps to run application program. Some of the popular operating systems are: Windows-7, Windows10, Unix, Linux, Mac - OS, etc. Functions of Operating System • Memory Management : Keeps track of primary memory i.e. what part of it is in use by whom, what part is not in use, etc. and allocates the memory when a process or program requests it. • Processor Management : Allocates the processor CPU to a process and deallocates processor when it is no longer required. • Device Management : Keeps track of all devices. This is also called I/O controller that decides which process gets the device, when, and for how much time. • File Management : Allocates and de-allocates the resources and decides who gets the resources. • Security : Prevents unauthorized access to programs and data by means of passwords. • Control over system performance : Records delays between request for a service and from the system. • Helps to execute commands and run application program.
GREEN Computer Book-8 29 Language processor A language processor is a special type of a computer software that has the capacity to translate the source codes (program codes) into machine codes. It is also called a language translator. There are three types of language processors: a. Interpreter: Interpreter translates program written in a high level language into a machine language. It translates the program code one after another. Source code Interpreter Object code b. Compiler: Compiler translates program written in a high level language into a machine language. It translates the whole program at once. Source code Compiler Object code c. Assembler: Assembler translates the program written in assembly language into a machine language. An assembler enables software and application develops to access, operate and manage a computer's hardware, architecture and components. Source code Assembler Object code Interpreter and compiler both translate high level language to machine language. But there are some differences between an interpreter and a compiler which are given below: Interpreter Compiler 1. Translates program one statement at a time. 1. Scans the entire program and translates it as a whole into machine code. 2. It takes less amount of time to analyze the source code but the overall execution time is slower. 2. It takes large amount of time to analyze the source code but the overall execution time is comparatively faster. 3. No intermediate object code is generated, hence is memory efficient. 3. Generates intermediate object code which further requires linking, hence requires more memory. 4. Easy for debugging. 4. Comparatively hard for debugging. 5. Programming language like Python, Ruby uses interpreters. 5. Programming language like C, C++ uses compilers.
30 GREEN Computer Book-8 Device Driver A device driver is a small piece of software that tells the operating system and other software how to communicate with a piece of hardware. Types of device drivers: printer drivers, display drivers, ROM drivers, BIOS drivers, USB drivers, VGA drivers, sound card drivers, mother board drivers, virtual device drivers. There are many more drivers included in a system. When a user is installing an operating system, it may automatically install the required drivers. Utility software Utility software is a part of system software that enhances the operations of computer or specific program. It manages memory, scans and stops viruses, compresses files, increases the speed of computer processing, scans disk to find bad sector of hard disk etc. Application Software Application softwares are designed to satisfy a particular need of a user. They are is directly designed for users. User can solve their various problems. Examples of application softwares are following: Payroll Software, Inventory Management Software, Microsoft Office, Microsoft Excel, etc. Features of application software are as follows: • Close to user. • Easy to design and develop. • More interactive. • Slow in operation. • Generally written in high-level language. • Easy to understand. • Bigger in size and requires large storage space.
GREEN Computer Book-8 31 There are two types of application softwares: Customized (Tailored Software) It is the software designed to address the user's need. It is developed on the demand of users to perform the user-specific task. It is very expensive. It is written in high level language. Some of the examples of customized software are library management system, payroll system, etc. Some of the leading software companies that who develop customized software are: Javra Software Nepal, Midas Technologies Pvt.Ltd, F1Soft Pvt Ltd, etc. Packaged Software It is user friendly software consisting of one or more programs created to perform a particular type of work. It is developed to fulfill common requirement of users. It can perform tasks like preparing document and presentation, keeping accounting records, maintaining database, playing audio and video, editing graphics, etc. Some examples of packaged software are: Word processing software: Word Pad, Note Pad, Ms-Word, etc. Database Management System Software: Microsoft Access, Oracle, SQL – Server, etc Spreadsheet software: Lotus1-2-3, Microsoft Excel, etc. Multimedia software: Window Media Player, Audio/ Video Converter, etc. Presentation software: Microsoft Power Point Graphics software: Adobe Photoshop, Flash, CorelDraw, etc. Web development software: PHP, Drupal, HTML, etc.
32 GREEN Computer Book-8 POINTS TO REMEMBER 1. Computer software is a set of programs that instruct a computer to perform certain task. 2. A device driver is a small piece of software that tells the operating system and other software how to communicate with a piece of hardware. 3. System software is a collection of programs designed to operate, control and manage the actual operation of the computer equipment. 4. Operating system software allows a computer to manage resources and control the overall functions of a computer. 5. Application softwares are those softwares which are designed for specific function directly for the user. 6. Software is a product. 7. There are two types of application software: Customized software and Packaged software. 8. Utility software is a part of system software that enhances the operations of computer or specific program. 9. A language processor is a special type of a computer software that has the capacity to translate the source code or program codes into machine codes. Exercise 1. Answer the following questions: a. Define software. Write its type. b. Explain system software. List out the features of system software. c. Write the functions of operating software. d. What is application software? What are the features of a computer? e. Why is customized software developed? f. Write a difference between packaged software and tailored software. g. What is language processor? List its types. h. Define the following: i. Device driver ii. Utility software iii. Compiler iv. Interpreter j. Write differences between applications, software and system software.
GREEN Computer Book-8 33 2. Fill in the blanks: a. ............................ software is very close to the system. b. ............................ software organizes and manages memory. c. ............................ software is close to the user. d. Unix is an example of ............................. e. ............................ is written in high level language. f. ............................ translate high level language into machine language. g. ............................ software is designed to address the user's need. 4. Match the following: a. Tailored software Set of programs b. Utility software Library management system c. Operating system Scan viruses d. Software Microsoft Office e. Packaged software used to coordinate the hardware of the computer 5. State whether these statements are 'True' or 'False': a. Packaged software manages files and folders. b. Linux is an application software. c. A computer is a useless machine without software. d. Windows 7 is an operating system. e. Packaged software is used to coordinate the hardware of a computer. f. Source code is written in low level language. 6. Write technical terms for the following statements: a. A set of instructions given to a computer to perform a task. b. A set of programs that tells computer hardware what to do and how to do. c. A software designed to perform general tasks. d. A software designed to perform specific tasks. e. A language processor that converts the whole program written in high level language into machine language. f. A language translator which translates the high level language one statement at a time into machine language.
34 GREEN Computer Book-8 Types of Operating System 5 Introduction The software which controls and coordinates overall functions of a computer is called operating system software. An operating system is a program that acts as an interface between the software and the computer hardware. An operating system is a software which performs all the basic tasks like file management, memory management, process management, handling input and output, and controlling peripheral devices such as disk drives and printers. It helps to run application programs. Some of the popular operating systems are: Windows 7, Windows 8, windows 10, Unix, Linux, VMS, OS/400, AIX, etc. Use of operating systems started with the development of modern computers (from the very first generation of computer) and they keep evolving with time. In this chapter, we will discuss some of the important types of operating systems which are most commonly used. Mainly there are two types of operating systems: 1. On the basis of Mode of User 2. On the basis of Interface 1. On the basis of Mode of User Following operating systems are categorized on the basis of mode of user. Batch Operating System The users of a batch operating system do not interact with a computer directly. Each user prepares his job on an off-line device like punch cards and submits it to the computer operator. To speed up processing, jobs with similar needs are batched together and run as a group. The programmers leave their programs with the operator and the operator then sorts the programs with similar requirements into batches.
GREEN Computer Book-8 35 Disadvantages of batch operating system: • Repeated jobs are done fast in batch systems without user interaction. • You don’t need special hardware and system support to input data in batch systems. • Best for large organizations but small organizations can also benefit from it. • Batch systems can work offline so it makes less stress on processor. • In batch systems the processor knows how long the job is as it is queued. • Sharing of batch system for multiple users. • The idle time batch system is very less. • You can assign specific time for the batch jobs so when the computer is idle it starts processing the batch jobs. The problems with Batch Systems are as follows: • Lack of interaction between the user and the job. • CPU is often idle, because the speed of the mechanical I/O devices is slower than the CPU. • It is costly and difficult to debug the batch system. • Difficult to provide the desired priority. • Computer operator must be trained for using batch system. Time-sharing Operating Systems Time-sharing is a technique which enables many people, located at various terminals, to use a particular computer system at the same time. Time-sharing or multitasking is a logical extension of multiprogramming. Processor's time which is shared among multiple users simultaneously is termed as timesharing. The main difference between Multi-programmed Batch Systems and TimeSharing Systems is that Multi-programmed Batch Systems maximize the use of processor but Time-Sharing Systems minimize the response time. Batch Computer Batch Job Jobs Jobs Job Job Job User User User User Operator
36 GREEN Computer Book-8 Advantages of Time sharing operating systems are as follows: • Provide the advantage of quick response. • Avoid duplication of software. • Reduce CPU idle time. Disadvantages of Time-sharing operating systems are as follows: • Problem of reliability. • Question of security and integrity of user programs and data. • Problem of data communication. Distributed Operating System Distributed systems use multiple central processors to serve multiple real-time applications and multiple users. Data processing jobs are distributed among the processors accordingly. The processors communicate with one another through various communication lines (such as high-speed buses or telephone lines). These are referred as loosely coupled systems or distributed systems. Processors in a distributed system may vary in size and function. These processors are referred as sites, nodes, computers, and so on. The advantages of distributed systems are as follows: • With resource sharing facility, a user at one site may be able to use the resources available at another. • Speedup the exchange of data with one another via electronic mail. • If one site fails in a distributed system, the remaining sites can potentially continue operating. • Better service to the customers. • Reduction of the load on the host computer. • Reduction of delays in data processing. Disadvantages of distributed operating systems:- • Security problem due to sharing • Some messages can be lost in the network system • Bandwidth is another problem if there is large data then all network wires to be replaced which tends to become expensive. • Overloading is another problem in distributed operating systems. • If there is a database connected on local system and many users accessing that database through remote or distributed way then performance becomes slow.
GREEN Computer Book-8 37 • The databases in network operating is difficult to administrate then single user system Network Operating System A Network Operating System runs on a server and provides capability to the server to manage data, users, groups, security, applications, and other networking functions. The primary purpose of a network operating system is to allow shared file and printer access among multiple computers in a network, typically a local area network (LAN), a private network or to other networks. Examples of network operating systems include Microsoft Windows Server 2003, Microsoft Windows Server 2012, UNIX, Linux, Mac OS X, and BSD. The advantages of network operating systems are as follows: • Centralized servers are highly stable. • Security is managed by server. • Upgrades to new technologies and hardware can be easily integrated into the system. • Remote access to servers is possible from different locations and types of systems. The disadvantages of network operating systems are as follows: • High cost of buying and running a server. • Dependency on a central location for most operations. • Regular maintenance and updates are required. Real-Time Operating System A real-time system is defined as a data processing system in which the time interval required to process and respond to inputs is so small that it controls the environment. The time taken by the system to respond to an input and display of required updated information is termed as the response time. So in this method, the response time is very less as compared to online processing. Real-time systems are used when there are rigid time requirements on the operation of a processor or the flow of data and real-time systems can be used as a control device in a dedicated application. A real-time operating system must have well-defined, fixed time constraints, otherwise the system will fail. For example, scientific experiments, medical imaging systems, industrial control systems, weapon systems, robots, air traffic control systems, etc.
38 GREEN Computer Book-8 Advantages of Real-Time Operating System • It takes very less time to respond the input and display of required updated information. • It works when there are rigid time required on the operation. • It guarantee that eritical task complete on time. • Task scheduling and shifting. • Task can have priority. • Inter task communication. • Portable. There are two types of real-time operating systems. Hard real-time systems Hard real-time systems guarantee that critical tasks complete on time. In hard real-time systems, secondary storage is limited or missing and the data is stored in ROM. In these systems, virtual memory is almost never found. Soft real-time systems Soft real-time systems are less restrictive. A critical real-time task gets priority over other tasks and retains the priority until it completes. Soft real-time systems have more limited utility than hard real-time systems. For example, multimedia, virtual reality, Advanced Scientific Projects like undersea exploration and planetary rovers, etc. 2. On the basis of Interface There are two types of operating systems on the basis of interface. a. Character User Interface (CUI) A CUI is a text-based interface where instructions are given to the computer by typing commands. In CUI, a user interacts with application software through the commands. It is also known as Command Line Interface (CLI). Novell Netware Server, MS-DOS, etc. are the CLI operating system. b. Graphical User Interface A Graphical User Interface (GUI) based operating system allows a user to interact with the computer system by pointing and selecting graphical symbols. Some of the GUI operating systems are: Windows 2007, Windows 2008, Vista, Windows XP, Mac-OS, etc.
GREEN Computer Book-8 39 POINTS TO REMEMBER 1. An operating system is a program that acts as an interface between the software and the computer hardware. 2. The use of operating systems started with the development of modern computer. 3. The users of a batch operating system do not interact with the computer directly. 4. Time-sharing is a technique which enables many people, located at various terminals, to use a particular computer system at the same time. 5. Distributed systems use multiple central processors to serve multiple real-time applications and multiple users. 6. A Network Operating System runs on a server and provides the server the capability to manage data, users, groups, security, applications, and other networking functions. 7. A real-time system is defined as a data processing system in which the time interval required to process and respond to inputs is so small that it controls the environment. Exercise 1. Answer the following questions: a. Define an operating system. Give some examples. b. List the types of operating systems on the basis of mode of users. c. What is batch operating system? What are the problems with batch operating system? d. What is time sharing operating system? Write advantages and disadvantages. e. Define the network operating system with examples. f. What are the advantages and disadvantages of network operating system? g. What is real time operating system? Write its types h. How many operating systems are there on the basis of interface?
40 GREEN Computer Book-8 2. Fill in the blanks: a. ........................... is a text-based interface where instructions are given to the computer by typing commands. b. ........................... based operating system allows a user to interact with the computer system by pointing and selecting graphical symbols. c. ........................... systems guarantee that critical tasks complete on time. d. ........................... have more limited utility than hard real-time systems. e. ........................... system is a software which performs all the basic tasks like file management, memory management, process management, handling input and output, and controlling peripheral devices such as disk drives and printers. 3. Write the full form of the following: GUI CLI OS I/O LAN CPU CUI 4. a. GU based operating system allows a user to interact with computer by typing commands. b. Soft real time operating system is less restrictive. c. Distributed opening system use, multiple central processor to serve multiple real-time application and user. d. Time sharing is physical extension of multi programming. e. The user of batch operating system interact with a computer directly. 5. Match the following. a. CLI i. complete critical tasks b. GUI ii. network O/S c. UNIX iii. donot interact with computer directly d. Batch O/S iv. Graphical user interface e. Hard real time system v. Command line interface
GREEN Computer Book-8 41 6 Number System Introduction A number system is a way of representing numbers. A set of values used to represent different quantities is known as a Number System. When we type some letters or words, the computer translates them in to numbers as the computer can understand only numbers. The number system can mainly be categorized into two types. 1. Non-Positional Number System: The number system in which different symbols are used in different positions and places is called non-positional number system. It does not make any positional significance on the value of the number system is called non-positional number system. The roman number system such as I, V, X, XII etc are used to represent non-positional number system. 2. Positional Number System: A computer can understand the positional number system. The positional number system uses different symbols at different positions or places that make the positional significance on the value of the number. There are different types of number systems: • Decimal Number System • Binary Number System • Octal Number System • Hexadecimal Number System Decimal Number System The number system that we use in our day-to-day life is the decimal number system. The decimal number system has base 10 as it uses 10 digits from 0 to 9. In the decimal number system, the successive positions to the left of Decimal Number Binary Number 0 0 1 1 2 10 3 11 4 100 5 101 6 110 7 111 8 1000 9 1001
42 GREEN Computer Book-8 the decimal point represent units, tens, hundreds, thousands and so on. Each position represents a specific power of the base 10. For example, the decimal number 3562 consists of the digit 2 in the units position, 6 in the tens position, 5 in the hundreds position, and 3 in the thousands position, and its value can be written as (3 x 1000) + (5 x 100) + (6 x 10) + (2 x l) (3 x 103 ) + (5 x 102 ) + (6 x 101 ) + (2 x 100 ) 3000 + 500 + 60 + 2 3562 Binary Number System A digital computer represents all kinds of data and information in the binary system. The Binary Number System consists of two digits 0 and 1. Its base is 2. 0 represents False or Off state and 1 represents True or On state. A combination of binary numbers may be used to represent different quantities like 1001. The positional value of each digit in binary number is twice the place value or face value of the digit of its right side. The weight of each position is a power of 2. The place value of the digits according to position and weight is as follows: Position 3 2 1 0 Weight 23 22 21 20 Example: 101012 = 1 × 24 + 0 × 23 + 1 × 22 + 0 × 21 + 1 × 20 = 16 + 4 + 1 = (21)10 Octal Number System The Octal Number System consists of eight digits from 0 to 7 (0, 1, 2, 3, 4, 5, 6, 7). The base of octal system is 8. Each digit position in this system represents a power of 8. Any digit in this system is always less than 8. Octal number system is used as a shorthand representation of long binary numbers. The place value Octal Number Binary number 0 0 1 1 2 10 3 11 4 100 5 101 6 110 7 111 8 1000 9 1001
GREEN Computer Book-8 43 of each digit according to position and weight is as follows. Position 4 3 2 1 0 Weight 84 83 82 81 80 Example: 278 = 2 × 81 + 7 × 80 = 16 + 7 = 2310 Octal Number Binary number 0 000 1 001 2 010 3 011 4 100 5 101 6 110 7 111 Hexadecimal Number System The Hexadecimal Number System consists of 16 digits from 0 to 9 and A to F. The alphabet letters A to F represent decimal numbers from 10 to 15. The base of this number system is 16. Each digit position in hexadecimal system represents a power of 16. This number system provides shortcut method to represent long binary numbers. The place value of each digit according to position and weight is as follows: Position 4 3 2 1 0 Weight 164 163 162 161 160 Example: 2F16 = 2 × 161 + 15 × 160 = 47 Number Conversion There are many methods for number conversion from one base to another base. We discuss about the following number conversion: Hexadecimal Number Binary number 0 0000 1 0001 2 0010 3 0011 4 0100 5 0101 6 0110 7 0111 8 1000 9 1001 A 1010 B 1011 C 1100 D 1101 E 1110 F 1111
44 GREEN Computer Book-8 • Binary to Decimal • Binary to Octal • Binary to Hexadecimal • Decimal to Binary • Octal to Binary • Hexadecimal to Binary • Decimal to Octal • Octal to Decimal Binary to Decimal (1101)2 = ( ? )10 Position 3 2 1 0 Weight 23 22 21 20 Face value 1 1 0 1 Step 1 : 1 x 23 + 1 x 22 + 0 x 21 + 1 x 20 Step2 : 1 x 8 + 1 x 4 + 0 x 2 + 1 x 1 =8 + 4 + 0 + 1 = (13)10 Binary to Octal Steps: • Make a group of three digits from right to left. • See in the table of octal equivalent binary. • Add zero to the left most side if there are less number of digits than three. (1101111)2 = ( ? )8 001 (added two zero) 101 111 1 5 7 = (157)8 Binary to Hexadecimal Steps: • Make a group of four digits from right to left. • See in the hexadecimal equivalent binary table.
GREEN Computer Book-8 45 • Add zero to the left most side if there are less number of digits than four. (111100101)2 = ( ? )16 0001 (added three zero) 1110 0101 1 E 5 = (1E5)16 Decimal to Binary Steps: • Divide the number by 2 each time. • Write the remainder (0 or 1). • Arrange remainder bottom to top. (52)10= ( ? )2 Operation Result Remainder 52/2 26 0 26/2 13 0 13/2 6 1 6/2 3 0 3/2 1 1 1/2 0 1 (110100)2 Octal to Binary Steps: • Plot the octal number in table. • See the octal equivalent binary table. • Write the equivalent binary number. (7602)8 = ( ? )2 7 6 0 2 111 110 000 010 (111110000010)2
46 GREEN Computer Book-8 Hexadecimal to Binary Steps: • Plot the hexadecimal number in table. • See the hexadecimal equivalent binary table. • Write the equivalent binary number. (AC107)16 = ( ? )2 A C 1 0 7 1010 1100 0001 0000 0111 (10101100000100000111)2 Decimal to Octal Steps: • Divide the number by 8 each time. • Write the remainder. • Arrange remainder bottom to top. (435)10 = ( ? )8 Operation Result Remainder 435/8 54 3 54/8 6 6 6/8 0 6 (663)8 Octal to Decimal (324)8 = ( ? )10 Position 2 1 0 Weight 82 81 80 Face value 3 2 4 Step 1: 3 x 82 + 2 x 81 + 4 x 80 Step 2: 3 x 64 + 2 x 8 + 4 x 1 Step 3: 192 + 16 + 4 = (212)10
GREEN Computer Book-8 47 Binary Calculation Binary number calculation includes: • Binary Addition, • Binary Subtraction, • Binary Multiplication and • Binary Division. We discuss only addition, subtraction and multiplication. Binary Addition Rules for binary addition 0 + 0 = 0 1 + 0 = 1 0 + 1 = 1 1 + 1 = 10 Binary Subtraction Rules for binary subtraction 0 – 0 = 0 1 – 0 = 1 1 – 1 = 0 0 – 1 = 1 ( by borrowing from left) Binary Multiplication Rules for binary multiplication 0 x 0 = 0 0 x 1 = 0 1 x 0 = 0 1 x 1 = 1 Example: 2 1 1 1 1 0 1 + 1 0 1 0 1 1 1 1 0 1 0 0 0 Example: 1 1 0 0 0 1 0 + 1 1 0 1 1 1 1 0 1 1 0 0 1 Example: 2 1 0 1 0 1 0 - 1 1 0 1 1 1 1 1 1 Example: 1 1 1 0 0 0 0 1 0 - 1 1 1 1 1 1 1 0 0 0 0 0 1 1 Example: 2 1 1 1 0 1 x 1 0 1 1 1 1 0 1 0 0 0 0 0 . 1 1 1 0 1 . 1 0 0 1 0 0 0 1 Example: 1 1 1 1 1 1 x 1 1 1 1 1 1 1 1 1 1 1 1 1 . 1 1 1 1 1 . 1 1 0 1 1 0 0 1
48 GREEN Computer Book-8 Binary Multiplication Rules for binary division, 0 ÷ 0 = 0 0 ÷ 1 = 0 1 ÷ 0 = not defined 1 ÷ 1 = 1 POINTS TO REMEMBER 1. A numbering system is a way of representing numbers. 2. In a number system, different symbols are used in different positions and places. 3. A computer can understand the positional number system. 4. The decimal number system has base 10 as it uses 10 digits from 0 to 9. 5. The Binary Number System consists of two digits 0 and 1. 6. The Octal Number System consists of eight digits from 0 to 7. 7. The Hexadecimal Number System consists of 16 digits from 0 to 9 and A to F. Exercise 1. Answer the following questions: a. List out four types of number systems. b. Give the importance of number systems. c. Differentiate between binary and decimal number system. d. Define the term radix in number base system. e. What is the hexadecimal number system? f. Explain octal number system in brief. 2. Convert the following binary number to decimal number system. a. 101002 = ( ? )10 b. 101112 = ( ? )10 c. 1001112 = ( ? )10 d. 1111012 = ( ? )10 Example: 1 101 101010 1000 101 × 010 Example: 1 100100 101 11011010 111 × 110 – 110 ×10
GREEN Computer Book-8 49 3. Convert the following decimal number to binary number system. a. (908)10 = ( ? )2 b. (75)10 = ( ? )2 c. (93)10 = ( ? )2 d. (101)10 = ( ? )2 4. Convert the following binary number to octal number system. a. (1011010)2 = ( ? )8 b. (1010111)2 = ( ? )8 c. (10101111010)2 = ( ? )8 d. (10111111)2 = ( ? )8 5. Convert the following binary number to hexadecimal number system. a. (1011010)2 = ( ? )16 b. (1010111)2 = ( ? )16 c. (10101111010)2 = ( ? )16 d. (10111111)2 = ( ? )16 6. Convert the following hexadecimal number to binary number system. a. (C09)16 = ( ? )2 b. (CAB)16 = ( ? )2 c. (1000EF)16 = ( ? )2 d. (1011)16 = ( ? )2 7. Convert the following decimal number to octal number system. a. (291)10 = ( ? )8 b. (203)10 = ( ? )8 c. (1909)10 = ( ? )8 d. (721)10 = ( ? )8 8. Convert the following octal number system to decimal number system. a. (100)8 = ( ? )10 b. (100)8 = ( ? )10 c. (1037)8 = ( ? )10 d. (172)8 = ( ? )10 9. Perform the binary calculation of the following. a. 1101110 + 101010 b. 10110 + 10111 - 1001 c. 100110 - 1101 d. 110001 x 11 e. 10111 x 101 f. 1110101 x 111 + 1111 g. 110101 + 111001 × 111 h. 1111111 × 10 – 111101 10. Perform following binary division. a. (1111001)/(111) b. (10101011)/(1010) c. (111110001)/(101) d. (11110101101)/(111) e. (10101010101)2 /(101)2 f. (10000001)2 /(100)
50 GREEN Computer Book-8 Advanced Features of Microsoft Word 7 Introduction Word processing is one of the most popular and widely used application softwares. Word processing relates to the work with the text. This software provides users to create, edit and format documents in systematic and scientific ways. Microsoft Word (MS Word) is one of the most popular word processing softwares. Before the use of computers or any other electronic devices, people used to write on paper to send letters and other informative matters on their own. Afterwards, they started using typewriters to do similar jobs. Later on, electronic typewriters and computers came into use. Then people started using such devices to prepare these informative matters. MS Word is a word processing program that allows for the creation of both simple and sophisticated documents. It has templates and wizards to help you create useful documents such as resumes, letters and fax cover sheets. There are also features that allow you to add professional looking graphics to your documents. MS-Word is available in different versions such as MS-WORD 6.0, MSWORD97, MS-WORD 2000 , MS-Word 2003, MS-Word 2007 and MS-Word 2010. They are MS-Word 2007 and MS-Word 2010 , which we will deal with in this lesson. It comes as a part of office package. All word processing softwares are word processors. You have studied most of the features of Ms-word previous classes. Now, you will study some advance features. Typing Text in Word Typing text on the left side of the screen. 1. Position your cursor where you would like to start typing. 2. Start typing.