Arihant Computer PDF

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wired-2.1 Pirated Copy Not Meant For Sale Students Wired Join Here  Chapterwise Theory Question Bank (MCQs) with each Chapter Chapterwise Past Years’ Questions 5 Practice Sets for Complete Practice Author Neetu Gaikwad ARIHANT PUBLICATIONS (INDIA) LIMITED Arihant Publications (India) Ltd. All Rights Reserved © PUBLISHERS No part of this publication may be re-produced, stored in a retrieval system or distributed in any form or by any means, electronic, mechanical, photocopying, recording, scanning, web or otherwise without the written permission of the publisher. Arihant has obtained all the information in this book from the sources believed to be reliable and true. However, Arihant or its editors or authors or illustrators don’t take any responsibility for the absolute accuracy of any information published and the damages or loss suffered there upon. All disputes subject to Meerut (UP) jurisdiction only. ADMINISTRATIVE & PRODUCTION OFFICES Regd. Office ‘Ramchhaya’ 4577/15, Agarwal Road, Darya Ganj, New Delhi -110002 Tele: 011- 47630600, 43518550; Fax: 011- 23280316 Head Office Kalindi, TP Nagar, Meerut (UP) - 250002 Tele: 0121-2401479, 2512970, 4004199; Fax: 0121-2401648 SALES & SUPPORT OFFICES Agra, Ahmedabad, Bengaluru, Bareilly, Chennai, Delhi, Guwahati, Hyderabad, Jaipur, Jhansi, Kolkata, Lucknow, Meerut, Nagpur & Pune ISBN : 978-93-13168-80-5 Published by Arihant Publications (India) Ltd. For further information about the books published by Arihant log on to www.arihantbooks.com or email to [email protected] /arihantpub /@arihantpub CONTENTS 1. Introduction to Computer 1-11 2. Computer Architecture 12-19 3. Computer Hardware 20-32 4. Computer Memory 33-44 5. Data Representation 45-54 6. Computer Software 55-62 7. Operating System 63-71 8. Programming Concepts 72-78 9. Microsoft Windows 79-89 10. Microsoft Office 90-112 11. Database Concepts 113-121 12. Data Communication and Networking 122-131 13. Internet and its Services 132-144 14. Computer Security 145-155 Ÿ Practice Sets (1-5) 156-175 Ÿ Abbreviations 176-179 Ÿ Glossary 180-186  C H A P T E R 01 INTRODUCTION TO COMPUTER The word computer has been derived from Latin language. A computer is an electronic device that manipulates information or data according to the set of instructions. It has the ability to store, retrieve and process data. A computer is used to type documents, send E-mails and browse the Internet. It is also used to handle accounting, database management, presentations, games and so on. Functioning of a Computer Computer performs four basic functions which are as follows 1. Input Information or data that is entered into a computer is called input. It sends data and instructions to the Central Processing Unit (CPU). 2. Processing It is the sequence of actions taken on data to convert it into information which is meaningful to the user. It can be calculations, comparisons or decisions taken by the computer. 3. Output It makes processed data available to the user. It is mainly used to display the desired result to the user as per input instructions. 4. Storage It stores data and programs permanently. It is used to store information during the time of program execution and possible to get any type of information from it. Features of Computer The key features of computer are as follows 1. Speed The computer can process data very fast at the rate of millions of instructions per second. 2. Accuracy Computers provide a high degree of accuracy. They respond to the user as per the input instructions. 3. Storage Capacity Computers are capable to store huge amount of data which depends on the capacity of hard disk. 4. Versatility Computers can do different types of work simultaneously. They can perform multiple tasks at a same time. 2 Learn, Revise & Practice ~ Computer Awareness 5. Automation Once the instruction to do any Terms Related to Computer work is given to the computer, the computer 1. Hardware It is the collection of physical does its work automatically by itself. elements that constitutes a computer system. It is a 6. Diligence Unlike human beings, a comprehensive term for all the physical parts of a computer is free from monotony, tiredness, computer. e.g. Display screens, discs, keyboards, lack of concentration, etc. and can work for etc. hours without creating any errors. 2. Software It is a set of programs and procedures. 7. Secrecy Leakage of information is reduced Software tells the hardware what to do and how to accomplish a task. e.g. Web browsers, word by creating login system with password processors, etc. protection. 3. Data Unprocessed raw facts and figures, like 8. Reliability Computers are more reliable numbers, text on piece of paper, are known as data. than human beings. Computers always produce exact results. The possibility of errors 4. Information When data is processed, organised, structured or presented in a given context so as to be occur only if the input is wrong, i.e. the useful, then it is called information. computers never make mistakes of their own accord. 5. Instruction It is a command given to a computer in the computer language by the user. 9. Plug and Play Computers have the ability to automatically configure a new hardware 6. Program It is a set of instructions given to a computer in order to perform some task. and software component. History of Computer Computer is not the creation of one day, rather it took a long period for the development of modern computer. History of computer is described in this table. Invention Inventor Characteristics Applications First mechanical calculating device. Used for addition and subtraction Abacus operations. 1602 China A horizontal rod represents the one, tens, hundred, etc. Calculation of square roots can also be performed. Three dimensional structure. Perform multiplication on numbers. Napier’s John Napier Holding numbers from 0 to 9 only. Technology used for calculation Bones (Scotland) called Rabdologia. Represent graphical structure of calculating 1617 result. First mechanical adding machine. Perform addition and subtraction of Pascaline Blaise Pascal It was structured like rectangular box, with two numbers. 1642 (France) eight disc (represent number of units). Mainly designed with regard to the pressure of liquid. Jacquard’s Joseph Marie Mainly weaved a silk based pattern. Simplified the process of Textiles. Loom Jacquard Used punched card for the sequence of 1801 (France) operation. Charles First general-purpose computer. It was a decimal machine used sign Analytical Babbage Stored program in the form of ‘pegs’ also and magnitude for representation of Engine (Father of called barrels. a number. 1837 Computer) (London) Introduction to Computer 3 Invention Inventor Characteristics Applications It used punched cards with round holes. Read one card at a time. Tabulating Herman It was the first electromechanical Machine Hollerith machine, designed to process the data for 1890 (America) census in 1890. Consists of interlocking panels of small Mainly used in the war effort during Howard glass, counters, switches and control World War-II. MARK-1 Aiken circuits. 1944 Magnetic drums are used for (America) storage. Data can be entered manually. JP Eckert and It is a combination of twenty accumulators. Used for weather prediction, atomic ENIAC JW Mauchly energy calculation and other First electronic digital computer. 1946 (America) scientific uses. It was first computer which provided Capable of storing instructions and EDSAC John Von storage capacity. data in memory. 1949 Neumann First computer program was run on Used mercury delay lines for (America) machine. memory, vacuum tubes for logic. J. Presper First general-purpose electronic computer Used magnetic tapes as input and UNIVAC Eckert and with large amount of input and output. output. 1951 John Mauchly (America) IBM-650 Provided input/output units converting Payroll processing Computer IBM Company alphabetical and special characters to Oil refinery design 1953 two-digit decimal code. Market research analysis Generations of Computer A generation refers to the state of improvement in the development of system. Computers are built of electromechanical, before generation. Each generation of computer is characterised by a major technological development that fundamentally changed the way, computers operate. Generation Switching Storage Operating System Characteristics Applications Device Device/Speed First Vacuum tubes Magnetic drums Batch operating system Fastest computing Used for scientific (1940-56) (333 micro (Machine language device. purpose e.g. ENIAC, seconds) (Binary number 0’s Generate large amount UNIVAC, MARK-1, and 1’s) of heat. etc. Non-portable. Second Transistors Magnetic core Time sharing OS, More reliable and less Used for commercial (1956-63) (Made up of technology Multitasking OS prone to hardware production semiconductor) (10 micro seconds) (Assembly language, failure. e.g. PDP-8, high level language) Portable and generate IBM-1401, etc. less amount of heat. Third Integrated Magnetic core Real-time system Consumed less power. Database (1964-71) Circuits (ICs) as primary storage (High level language Highly sophisticated management system (Made up of medium (100 nano (FORTRAN, COBOL, technology required. e.g. NCR-395, B6500, silicon) seconds) ALGOL)) etc. 4 Learn, Revise & Practice ~ Computer Awareness Generation Switching Storage Operating System Characteristics Applications Device Device/Speed Fourth Large Scale Semi conductor Time sharing, GUI More reliable and Distributed system, (1971- Integrated (LSI) memory, interface (PASCAL, portable. e.g. Intel 4004 chip, Present) circuit micro- Winchester disc ADA, COBOL-74, This generation leads Macintosh. processor (300 nano FORTRAN IV) to better seconds) communication and resource sharing Fifth Super Large Scale Optical disc Knowledge Parallel processing. Artificial intelligence (Present and Integrated (SLSI) Information Processing Intel core micro- e.g. Robotics Beyond) chips System processor is implemented. Enables mega chips. Tit-Bits Siddhartha was the first computer developed in India. Alan Turing is known as the father of the modern computer. John Von Neumann was introduced first architecture of computer in the year 1948. Transistors were invented by Bell Laboratory. In 1958, Jack St. Clair Kilby and Robert Noyce invented the first IC. In latest generation computers, the instructions are executed parallel as well as sequential. Classification of Computer Computers are mainly classified in three types as follows Classification of Computer Based on Size Based on Work Based on Purpose Microcomputer Minicomputer Analog Hybrid General Special Computer Computer Purpose Purpose Mainframe Supercomputer Digital Computer Computer Computer Computer Based on Size On the basis of size, computers are categorised as follows Microcomputer These types of computers are the least powerful, yet the most widely used and are also called portable computers. Microcomputer consists of three basic categories of physical equipment, i.e. system unit, input/output unit and memory unit. Some types of microcomputer are as follows (a) Desktop Computer or Personal Computer (PC) These are small, relatively economical computers. These are based on the microprocessor technology (Integrated Circuit-IC). (b) Laptop These computers are also known as ultra book or notebook. These are portable and lightweighted. They include rechargeable battery, so these can work anywhere. Introduction to Computer 5 (c) Handheld or Palmtop Supercomputers are used for highly calculation Computer These are the smallest and are intensive tasks, such as weather forecasting, designed to fit into the palm. So, these are nuclear research, military agencies and scientific also known as Palmtop. They are practical research laboratories. for certain functions such as phone books (i) CRAY-1 was the world’s first supercomputer and calendars. They use the pen for input introduced by Seymour R CRAY in 1976. instead of keyboard. e.g. PDA (Personal (ii) PARAM was the first supercomputer Digital Assistant), tablets, etc. developed in India in 1990. (d) Tablet Computer They have key (iii) PARAM ISHAN is the latest machine in features of the notebook computer, but the series of PARAM made by C-DAC and these can accept input from a pen instead of IIT Guwahati on 20th September, 2016. the keyboard or mouse. (e) Workstation Computer These are Based on Work computers dedicated to a user or group of On the basis of work, computers are categorised as users engaged in business or professional follows work. It includes one or more high resolution displays and a faster processor Analog Computer than a Personal Computer (PC). These computers carry out arithmetic and logical operations by manipulating and processing of Minicomputer data. e.g. Speedometers, seismograph, etc. These are smaller in size, faster and cost lower Analog computer can perform several than mainframe computers. Initially, the mathematical operations simultaneously. It uses minicomputer was designed to carry out some continuous variables for mathematical operations specific tasks, like engineering and Computer and utilises mechanical or electrical energy. Aided Design (CAD) calculations. But now, they are being used as central computer which is Digital Computer known as Server. Minicomputers are IBM-17, DEC These do work by calculating the binary digits. PDP-11, HP-9000, etc. A digital computer, not only performs Mainframe Computer mathematical calculations, but also combines the These types of computers having large internal bytes to produce desired graphics, sounds. memory storage and comprehensive range of e.g. Desktop (PC). software. Mainframe computer serves as a backbone for the entire business world. It is Hybrid Computer considered as the heart of a network of computers These are the combination of analog and digital or terminals that allow a large number of people computers. Machines used in hospitals like ECG and to work at the same time. Mainframe computers DIALYSIS are the commonly used hybrid computers. are IBM-370, IBM-S/390, UNIVAC-1110, etc. Based on Purpose Supercomputer On the basis of purpose, computers are categorised These are the fastest and most expensive as follows machines. They have high processing speed General Purpose Computer compared to other computers. Supercomputers are most powerful, large in size and memory, General purpose computers are those computers, compared to all other computers. which are used to solve variety of problems by changing the program or instructions. e.g. To make The speed of supercomputers are measured in small database, calculations, accounting, etc. FLOPS (Floating Point Operations Per Second). 6 Learn, Revise & Practice ~ Computer Awareness Special Purpose Computer 2. Education Computer is a very effective tool Special purpose computers are those computers which can be used for teaching and learning, which are used to solve a single and dedicated result processing, student data processing, notes preparation, etc. types of problem. e.g. Automatic aircraft landing, multimedia computer, etc. 3. Entertainment Different types of entertainment fields such as multimedia, film Quantum computer was first introduced by Richard making with animation, graphics, audio and Feynman. It uses quantum mechanical phenomena. visual design are done with the help of It is the fastest computer imitating brain working. computer. Nano computer is a general team used to describe a 4. Offices Computers are used for preparing computer smaller than a microcomputer, usually reports, storing/deleting reports, updating about the size of a credit card. e.g. Raspberry Pi reports, etc. in office. which could be used in schools to teach science to children. 5. Advertisement Computers are used in the different fields of advertisement such as Pratyush India’s fastest and first multi-petaflops (PF) supercomputer named Pratyush was unveiled at Pune- business advertisement, film advertisement, based Indian Institute of Tropical Meteorology (IITM). education advertisement, etc. Pratyush has 6.8 PF computational power installed at 6. Business Computers are used in business two MoES Institutes. 4.0 Peta Flops HPC facility at for accounting, keeping all records up-to IITM, Pune and 2.8 Peta Flops facility at NCMRWF, date, etc. Noida. Pratyush is fourth fastest supercomputer in the Artificial Intelligence (AI) is an area of computer world dedicated for weather and climate research. science that emphasises the creation of intelligent Note PF is a measure of a computer’s processing machines that work and react like humans. Some of speed. the activities computers with AI are designed for include : speech recognition, learning, planning, problem solving, etc. Applications of Computer Some of the areas where computers are being used are Robotics is the branch of engineering and science as follows that deals with the design, construction, operation and use of robots as well as computer systems for 1. Banking Computers are used in bank for their control, sensory feedback and information electronic money transfer, making deposits, processing. voucher, bank sheet, etc.  QUESTION BANK 1. The word computer has been derived from 9. A collection of unprocessed items is which of the following language? [SBI PO 2015] (1) Greek (2) English (1) information (2) data (3) Hindi (4) Latin (3) memory (4) reports (5) None of these 2. Input, output and processing devices grouped together represent a(n) 10. Which among the following cycle consists (1) mobile device of an input, processing, output and storage (2) information processing cycle as its constituents? [IBPS Clerk Mains 2017] (3) circuit board (1) Processing (2) Output (4) computer system (3) Input (4) Storage 3. Which of the following is the correct order (5) Data of the four major functions of a computer? 11. ……… is data that has been organised and (1) Process, Output, Input, Storage presented in a meaningful fashion. (2) Input, Output, Process, Storage [IBPS Clerk Mains 2017] (3) Process, Storage, Input, Output (1) A process (2) Software (4) Input, Process, Output, Storage (3) Storage (4) Information 4. Collecting the data and converting it into (5) Data information is called 12. Data or information used to run the (1) processing (2) compiling computer is called [IBPS Clerk 2013] (3) importing (4) exporting (1) hardware (2) CPU (5) None of these (3) peripheral (4) software 5. Computer cannot perform (5) None of these (1) input (2) output 13. The steps and tasks needed to process data, (3) thinking (4) processing such as responses to questions or clicking 6. A computer cannot perform which of the an icon, are called [IBPS Clerk Mains 2017] following functions? [IBPS Clerk 2015] (1) instructions (1) Addition (2) Subtraction (2) the operating system (3) Bake a cake (4) Division (3) application software (5) None of these (4) the system unit 7. Part number, description and number of parts (5) the hardware unit ordered are examples of [IBPS Clerk 2013] 14. The earliest calculating device is (1) control (2) output (1) calculator (3) processing (4) feedback (2) abacus (5) input (3) difference engine 8. Benefits of computers are (4) analytical engine (1) very fast and can store huge amount of data (5) None of the above (2) provide accurate output either input is correct or not 15. Abacus can perform (3) think about the processing (1) addition (2) subtraction (4) All of the above (3) multiplication (4) Both ‘1’ and ‘2’ 8 Learn, Revise & Practice ~ Computer Awareness 16. The Napier’s technology used for 26. Computer size was very large in calculation called (1) first generation (2) second generation (1) Naptologia (2) Vibologia (3) third generation (4) fourth generation (3) Semiconductor (4) Rabdologia 27. First generation computers were based on 17. Pascaline is also known by (1) transistors (2) conductors (1) abacus (2) adding machine (3) ICs (4) vacuum tubes (3) division machine (4) difference machine 28. Computer built before the first generation 18. Punched cards were first introduced by computer was (1) Powers (2) Pascal (1) mechanical (2) electromechanical (3) Jacquard (4) Herman Hollerith (3) electrical (4) electronics (5) None of these 29. First generation computers used......... 19. Which of the following is known as father languages. [SBI Clerk 2012] of computer? (1) machine (2) assembly (1) Dennis Ritchie (2) Napier (3) Both ‘1’ and ‘2’ (4) high level (3) Charles Babbage (4) Alan Turing (e) None of these 20. Analytical Engine developed by 30. Speed of first generation computer was in (1) Blaise Pascal (2) Charles Babbage [IBPS Clerk 2012] (3) Dennis Ritchie (4) Alan Turing (1) nano seconds (2) milli seconds (3) nano-milli seconds (4) micro seconds 21. The Analytical Engine developed during (5) None of these first generation of computers used......... as a memory unit. [RBI Grade B 2012] 31. The period of the second generation (1) RAM (2) floppies computers was (3) cards (4) counter wheels (1) 1946-1958 (2) 1940-1960 (5) None of these (3) 1956-63 (4) 1957-1964 22. Tabulating machine was the first 32. Time sharing became possible in......... electromechanical machine developed by generation of computers. [SBI PO 2011] (1) Herman Hollerith (2) Howard Aiken (1) first (2) second (3) third (4) fourth (3) Blaise Pascal (4) John Napier (5) None of these 23. Who designed the first electronic 33. Integrated Chips or IC’s were started to be computer-ENIAC? use from which generation of computers? [IBPS PO 2016] (1) Von Neumann (2) Joseph M Jacquard (1) 1st Generation (2) 2nd Generation (3) Presper Eckert and John W Mauchly (3) 3rd Generation (4) 4th Generation (4) All of the above (5) 5th Generation 24. The first computer which provides storage 34. Chip is a common nickname for a(n) [IBPS Clerk 2014, 15] is [SSC CPO 2012] (1) transistor (2) resistor (1) EDSAC (2) EDVAC (3) integrated circuit (4) semiconductor (3) MARK-I (4) ACE (5) None of these 25. Name the first general purpose electronic 35. The third generation computers were made computer. [IBPS PO 2012] with [SBI PO 2014] (1) ADVAC (2) ADSAC (1) bio chips (2) transistors (3) UNIVAC (4) EDVAC (3) integrated circuits (4) vacuum tubes (5) None of these (5) discrete components Introduction to Computer 9 36. Integrated Circuit (IC) or chips used in 44. Microcomputer hardware consists of three computers are made with [IBPS Clerk 2014] basic categories of physical equipment (1) copper (2) aluminium (1) keyboard, monitor, hard drive (3) gold (4) silicon (2) system unit, input/output, memory (5) silver (3) system unit, input/output, secondary storage (4) system unit, primary storage, secondary 37. A complete electronic circuit with storage transistors and other electronic components 45. Which of the following options correctly on a small silicon chip is called a(n) expresses the meaning of the term ‘PCs’? [RBI Grade B 2012] [IBPS PO 2012] (1) workstation (2) CPU (1) Independent computers for all working staff (3) magnetic disc (4) integrated circuit (2) Personal computers widely available to (5) complex circuit individual workers with which they can access 38. PCs are considered fourth-generation and information from layer systems and increase contain [SBI PO 2014] their personal productivity (1) information (3) Packed computers system formed by (2) data joining together of various computer (3) vacuum tubes terminals (4) microprocessors (4) Computer manufactured by the Pentium (5) transistors Company (5) None of the above 39. Artificial Intelligence is an example of (1) first generation computer 46. Which of the following is a small micro- (2) second generation computer processor based computer designed to be used (3) third generation computer by one person at a time? [SBI Clerk 2014] (4) fourth generation computer (1) Netbook (2) Supercomputer (5) fifth generation computer (3) All-in-one (4) Notebook (5) Personal computer 40. First computer of India is (1) PARAM (2) Siddhartha 47. Tablet PC is a type of (3) IBM-370 (4) CRAY-1 (1) microcomputer (2) supercomputer (3) minicomputer (4) mainframe computer 41. Computer’s basic architecture was developed by 48. Computers that are portable and convenient (1) John Von Neumann to use for users who travel, are known as (2) Charles Babbage (1) supercomputers (2) minicomputers (3) Blaise Pascal (3) mainframe computers (4) laptops (4) Jordan Murn 42. Who developed integrated chip? 49. Desktop and personal computers are also known as [SBI Clerk 2012] (1) Robert Nayak (2) C Babbage (1) supercomputers (2) servers (3) JS Kilby (4) CV Raman (3) mainframes (4) peripheral equipment 43. In latest generation computers, the (5) microcomputers instructions are executed 50. Which of the following uses a handheld (1) only parallel operating system? [SBI PO 2013] (2) only sequentially (1) A supercomputer (2) A personal computer (3) Both ‘1’ and ‘2’ (3) A laptop (4) A mainframe (4) Either ‘1’ or ‘2’ (5) A PDA 10 Learn, Revise & Practice ~ Computer Awareness 51. Palmtop computer is also known as 61. Which of the following is the India’s first (1) personal computer multi-petaflops (PF) supercomputer? (2) notebook computer (1) PARAM (2) Pratyush (3) tablet PC (3) PARAM Ishan (4) Tianhe-2 (4) handheld computer 62. Analog computer works on the supply of 52. A central computer that holds collections of (1) continuous electrical pulses data and programs for many PCs, (2) electrical pulses but not continuous workstations and other computers is a (3) magnetic strength (1) supercomputer (2) minicomputer (4) physical strength (3) laptop (4) server 63. Seismograph is an example of 53. Which computer is used for Computer (1) Analog computer (2) Digital computer Aided Design (CAD) calculations? (3) Hybrid computer (4) All of thes (1) Minicomputer (2) Mainframe computer (3) Supercomputer (4) Microcomputer 64. These computers work by calculating the binary digits. 54. Which of the following is generally costlier? (1) Hybrid (2) Digital [SBI Clerk 2012, IBPS Clerk 2015] (3) Analog (4) General purpose (1) Server (2) Notebook computer 65. Choose the odd one out. [IBPS Clerk 2011] (3) Personal computer (4) Laptop computer (1) Microcomputer (5) Mainframe (2) Minicomputer 55. The user generally applies......... to access (3) Supercomputer mainframe or supercomputer. (4) Digital computer (1) terminal (2) node (5) Notebook computer (3) desktop (4) handheld 66. A hybrid computer is the one having the 56. These are specially designed computers that combined properties of [SBI Clerk 2013] perform complex calculations extremely (1) super and microcomputers rapidly. (2) mini and microcomputers (1) Servers (2) Supercomputers (3) analog and digital computers (3) Laptops (4) Mainframes (4) super and mini computers (5) None of the above 57. A......... is a large and expensive computer 67. Which types of computer are used in capable of performing scientific and hospitals like ECG and DIALYSIS? business applications. (1) Digital (2) Hybrid (1) supercomputer (2) mainframe computer (3) Analog (4) Microcomputer (3) minicomputer (4) handheld computer 68. General purpose computers are used for 58. First supercomputer developed in India is (1) creating a small database (1) PARAM (2) CRAY-1 (2) performs calculation (3) PARAM ISHAN (4) EPRAM (3) accounting 59. Pratyush is …… fastest supercomputer in (4) All of the above the world. 69. Which is not the example of special purpose (1) first (2) second computer? (3) third (4) fourth (1) Automatic aircraft landing 60. Pratyush supercomputer is dedicated for (2) Word processor (1) multimedia (2) weather forecasting (3) Multimedia computer (3) recreation (4) military personnel (4) All of the above Introduction to Computer 11 70. Which type of computer is used in 72. In which of the following computers are used? automatic aircraft landing? (1) Banking (2) Education (1) General computer (3) Offices (4) All of these (2) Supercomputer 73. It is the science that attempts to produce (3) Special purpose computer machines that display the same type of (4) Microcomputer intelligence that humans do 71. Which of the following is the smallest and (1) Nano science fastest computer imitating brain working? (2) Nano technology [IBPS PO 2012] (3) Simulation (1) Supercomputer (4) Artificial Intelligence (AI) (2) Quantum computer (3) Param-10000 74. Which of the following deals with the design, (4) IBM chips construction, operation and use of robots? (5) None of these (1) Robotics (2) Artificial Intelligence (3) Nano computer (4) Quantum computer ANSWERS 1. (4) 2. (4) 3. (4) 4. (1) 5. (3) 6. (3) 7. (3) 8. (1) 9. (2) 10. (5) 11. (4) 12. (5) 13. (1) 14. (2) 15. (4) 16. (4) 17. (2) 18. (3) 19. (3) 20. (2) 21. (4) 22. (1) 23. (3) 24. (1) 25. (3) 26. (1) 27. (4) 28. (2) 29. (1) 30. (4) 31. (3) 32. (2) 33. (3) 34. (3) 35. (3) 36. (4) 37. (4) 38. (4) 39. (5) 40. (2) 41. (1) 42. (3) 43. (3) 44. (2) 45. (2) 46. (5) 47. (1) 48. (4) 49. (5) 50. (5) 51. (4) 52. (4) 53. (1) 54. (5) 55. (2) 56. (2) 57. (1) 58. (1) 59. (4) 60. (2) 61. (2) 62. (1) 63. (1) 64. (2) 65. (4) 66. (3) 67. (2) 68. (4) 69. (2) 70. (3) 71. (2) 72. (4) 73. (4) 74. (1) 75. (3) 76. (2) 77. (1)  C H A P T E R 02 COMPUTER ARCHITECTURE Computer architecture deals with the functional behaviour of a computer system as viewed by a programmer. It can also be described as the logical structure of the system unit that housed electronic components. The computer architecture forms the backbone for building successful computer systems. The first computer architecture was introduced in 1970. CPU Control Unit (CU) Arithmetic Logic Unit (ALU) Primary Input Storage Unit Output Control flow Unit Unit Data flow Secondary Storage Unit Computer Architecture Components of Computer A computer consists of following three main components 1. Input/Output (I/O) Unit 2. Central Processing Unit 3. Memory Unit Note System unit is a metal or plastic case that holds all the physical parts of the computer. The components that process data are located in it. Computer Architecture 13 Central Processing Unit is often called the brain Input Unit of computer. The CPU is fabricated as a single The computer accepts coded information through Integrated Circuit (IC) and is also known as input unit by the user. It is a device that is used to microprocessor. give required information to the computer. e.g. Keyboard, mouse, etc. A CPU controls all the internal and external devices and performs arithmetic and logic An input unit performs the following functions operations. (i) It accepts the instructions and data from The CPU consists of following main sub-systems the user. (ii) It converts these instructions and data in Arithmetic Logic Unit (ALU) computer in acceptable format. ALU contains the electronic circuitry that (iii) It supplies the converted instructions and executes all arithmetic and logical operations on data to the computer system for further the available data. ALU uses registers to hold processing. the data that is being processed. Most ALUs can perform the following operations Output Unit (i) Logical operations (AND, NOT, OR, XOR). This unit sends the processed results to the user. It (ii) Arithmetic operations (addition, is mainly used to display the desired result to the subtraction, multiplication and division). user as per input instruction. e.g. Monitor, printer, (iii) Bit-shifting operations (shifting or rotating plotter, etc. a word by a specified number of bit to the The following functions are performed by an left or right with or without sign output unit extension). (i) It accepts the results produced by the (iv) Comparison operations (=, , > =) computer which are in coded form and hence cannot be easily understood by user. Registers (ii) It converts these coded results to human These are used to quickly accept, store and acceptable form. transfer data and instructions that are being used (iii) It supplies the converted results to the user. immediately by the CPU. These registers are the top of the memory hierarchy and are the fastest way for the system to manipulate data. The number and Central Processing size of registers vary from processor to processor. Unit (CPU) It consists a set of registers, arithmetic logic unit Control Unit (CU) and control unit, which together interpret and CU coordinates with the input and output execute instructions in assembly language. devices of a computer. It directs the computer to The primary functions of the CPU are as follows carry out stored program instructions by (i) The CPU transfers instructions and input communicating with the ALU and the registers. data from main memory to registers, i.e. It organises the processing of data and internal memory. instructions. (ii) The CPU executes the instructions in the The basic function of control unit is to fetch the stored sequence. instruction stored in the main memory, identify (iii) When necessary, CPU transfers output data the operations and the devices involved in it and from registers to main memory. accordingly generate control signals. 14 Learn, Revise & Practice ~ Computer Awareness Microprocessor Interconnection of Units It is the controlling element in a computer system and CPU sends data, instructions and information to is sometimes referred to as the chip. Microprocessor the components inside the computer as well as to is the main hardware that drives the computer. It is a the peripheral devices attached to it. large Printed Circuit Board (PCB), which is used in all electronic systems such as computer, calculator, A bus is a set of wires used for interconnection, digital system, etc. The speed of CPU depends upon where each wire can carry one bit of data. the type of microprocessor used. In other words, bus is a set of electronic signal Intel 4004 was the first microprocessor made by pathways that allows information and signals to Intel in 1971 by scientist Ted Hoff and engineer Frederico Faggin. travel between components inside or outside of a Some of the popular microprocessors are Intel, Intel computer. core i7, Dual core, Pentium IV, etc. A computer bus can be divided into two types 1. Internal Bus The internal bus connects Memory Unit components inside the motherboard like This unit is responsible to store programs or data CPU and system memory. It is also called the on a temporary or permanent basis. It has primary system bus. memory (main memory) and secondary memory Internal bus includes following buses (auxiliary memory). (i) The command to access the memory or the The input data which is to be processed is brought I/O devices is carried by the control bus. into main memory before processing. (ii) The address of I/O devices or memory is Another kind of memory is referred to as carried by the address bus. The data to be secondary memory of a computer system. This unit transferred is carried by the data bus. is used to permanently store data, programs and 2. External Bus It connects the different output. This unit does not deal directly with CPU. external devices; peripherals, expansion slots, I/O ports and drive connections to the Motherboard rest of computer. It is also referred to as the The main circuit board contained in any computer expansion bus. is called a motherboard. It is also known as the main board or logic board or system board or Tit-Bits planar board. All the other electronic devices and UPS (Uninterruptible Power Supply), is an circuits of computer system are attached to this electrical apparatus that provides emergency board like, CPU, ROM , RAM, expansion slots, PCI power to a load when the input power source or slots and USB ports. It also includes controllers for mains power fails. Buffer is a temporary storage where register devices like the hard drive, DVD drive, keyboard holds the data for further execution. and mouse. In other words, motherboard makes Accumulator is a register in a CPU in which everything in a computer work together. intermediate arithmetic and logic results are stored. Components on An uniform interval of CPU time allocated for use in performing a task is known as time slice. Motherboard The speed of processor is measured in millions Various components on motherboard are as follows of cycles per second or megahertz (MHz) by clock speed. (i) CMOS Battery (ii) BIOS Chip DMA (Direct Memory Access) is a method that (iii) Fan (iv) Expansion Slot allows an input/output device to send or receive (v) SMPS (vi) PCI Slot data directly to or from the main memory, by passing the CPU to speed up memory (vii) Processor Chip (viii) Buses operations. Computer Architecture 15 Instruction Cycle Instructions Format It represents the sequence of events that takes Computer understands instructions only in terms place as an instruction is read from memory and of 0’s and 1’s, which is called the machine executed. language. A computer program is a set of Fetch instructions that describes the steps to be performed for carrying out a computational task. The processor must have two inputs; instructions and data. The instructions tell the processor what actions Instruction Store Cycle Decode are needed to be performed on the data. An instruction is further divided into two parts; operation (op-code) and operand. Execute The op-code represents action that the processor must execute and operand defines the parameters A simple instruction cycle consists of the following of the action and depends on the operation. steps 1. Fetching the instruction from the memory. Tit-Bits 2. Decoding the instruction for operation. Machine cycle is defined by the time, that takes 3. Executing the instruction. to fetch two operands from registers and performs ALU operation and stores the result in a register. 4. Storing in memory. Pipelining improves execution speed by putting In above steps, step 1 and 2 instructions are same the execution steps of several instructions into parallel. It is called implement instruction prefetch. and known as fetch cycle and step 3 and 4 Sockets are the connecting points of chip on the instructions are different and known as execute cycle. motherboard. QUESTION BANK 1. The basic function (s) performed by 4. Which circuit board is used in all electronic computer is/are systems such as computer, calculators, (1) data processing (2) data storage digital system? (1) Architecture (2) Printer (3) data movement (4) data control (3) Value (4) Register (5) All of these 5. The system unit 2.............. forms the backbone for building (1) coordinates input and output devices successful computer system. (2) is the container that houses electronic (1) Computer architecture components (3) is a combination of hardware and software (2) Computer model (4) controls and manipulates data (3) Computer instructions (4) None of the above 6. Which of the following is metal or plastic case that holds all the physical parts of the 3. The first computer architecture was computer? [IBPS Clerk Mains 2017] introduced in (1) System unit (2) CPU (1) 1970 (2) 1968 (3) 1971 (4) 1973 (3) Mainframe (4) Platform (5) Microprocessor 16 Learn, Revise & Practice ~ Computer Awareness 7. The components that process data are 16. The Central Processing Unit (CPU) in a located in which of the following? computer consists of [IBPS Clerk Mains 2017] (1) input, output and processing (1) Input devices (2) Output devices (2) control unit, primary storage and secondary (3) System unit (4) Storage component storage (5) Expansion board (3) control unit, arithmetic logic unit, memory unit (4) All of the above 8. Which of the following is not responsible for the performance of the computer? 17. Which instruction is used for loading data [IBPS Clerk Mains 2017] into CPU accumulator register from memory? (1) number of keys in the keyboard (1) Load (2) Storage (2) format of the video/graphics word (3) Machine (4) Access (3) memory in the video/graphics word 18. Where does computer add and compare data? (4) the clock speed of the processor (1) Hard disc (2) Floppy disc (5) number of cores available in the processor (3) CPU chip (4) Memory chip 9. A(n)......... device is any device that provides information, which is sent to the CPU. 19. What is the brain of the computer? [SSC CGL 2016] (1) input (2) output (1) Keyboard (2) Mouse (3) CPU (4) memory (3) CPU (4) Printer 10. Which of the following includes as a type of input? 20. CPU is fabricated as a single integrated circuit which is known as (1) data (2) programs (1) Motherboard (2) Microprocessor (3) commands (4) user response (3) ALU (4) CU (5) All of these 11. Information that comes from external 21. The CPU chip used in a computer is source and fed into computer software is partially made of called. [IBPS RRB PO Mains 2017] (1) copper (2) iron (3) gold (4) silica (1) Output (2) Input 22. The main job of a CPU is to (3) Throughout (4) Reports (1) carry out program instructions (5) Process (2) store data/information for further use 12. Input unit converts data in computer in........ (3) process data and information (4) Both 1 and 3 (1) suitable (2) acceptable (3) understandable (4) rejectable 23. The main purpose of time-sharing 13. This unit sends the processed results to the techniques used in computers is to make the user. best use of the (1) Input (2) Output (1) CPU (2) peripherals (3) Memory (4) CPU (3) secondary storage (4) floppy discs 14. Output unit includes 24. The CPU is made up of two smaller (1) plotter (2) printer components (3) monitor (4) All of these (1) ALU and CU (2) ALU and RAM (3) RAM and ROM (4) RAM and CUz 15. This component is required to process data into information and consists of integrated 25. The CPU comprises of control, memory and circuits. [SBI Clerk 2011]..... units. [SBI PO 2013] (1) Hard disk (2) RAM (1) microprocessor (2) arithmetic/logic (3) CPU (4) ROM (3) output (4) ROM (5) None of these (5) input Computer Architecture 17 26. What is the responsibility of the logical unit 34. Which unit is a combinational digital in the CPU of a computer? [IBPS Clerk 2015] electronic circuit that performs arithmetic (1) To produce result and bitwise operations on integer binary (2) To compare numbers numbers? [IBPS RRB PO Mains 2017] (3) To control flow of information (1) BOU (2) AEU (3) CPU (4) ALU (4) To do Maths work (5) UPS (5) None of the above 35. Internal memory in a CPU is nothing but 27. Which unit of computer helps in (1) a set of registers (2) a set of ALU communication between the memory and (3) microprocessor (4) bus the arithmetic logical unit? 36. Which among the following is a small set of [IBPS RRB PO Mains 2017] data holding place that is a part of the (1) CMU (2) CCU computer processor and may hold an (3) UPS (4) CPU (5) ALU instruction, a storage address, or any kind of data? [IBPS RRB PO Mains 2017] 28. Which part of the computer is used for (1) Register (2) WAN calculating and comparing? [IBPSClerk2013] (3) Bus (4) Address (1) ALU (2) Control unit (5) Processor (3) Disc unit (4) Modem (5) None of these 37. The portion of the CPU that coordinates the activities of all the other computer 29. Pick the one that is used for logical operations or comparisons such as less than, components is the [SBI PO 2015] equal to or greater than etc. (1) motherboard (2) coordination board (1) ALU (2) CU (3) control unit (4) arithmetic logic unit (3) Input unit (4) MU (5) None of these 30. What does ALU in computing denote? 38. Which among the following is an important [IBPS Clerk 2014] circuitry in a computer system that directs (1) Application and Logic Unit the operation of the processor? (2) Algorithm Logic Unit [IBPS PO 2016] (3) Arithmetic Layered Unit (1) Memory (2) Address Bus (4) Arithmetic Legal Unit (3) Accumulator (4) ALU (5) Arithmetic Logic Unit (5) Control unit 31. How many types of arithmetic operations 39. The part of a computer that coordinates all does the ALU of computer perform? its functions, is called its [IBPS Clerk Mains 2017] (1) 4 (2) 2 (1) ROM program (2) System board (3) 5 (4) 8 (3) Arithmetic logic unit (4) Control unit 32. Processors contain a control unit and a/an : (5) None of these (1) Control unit [SSC CGL 2016] 40. The control unit controls other units by (2) Primary storage unit generating [IBPS Clerk 2011] (3) Input unit (1) control signal (2) timing signal (4) Arithmetic logic unit (3) transfer signal (4) command signal 33. Which of the following executes the 41. Control unit of a digital computer is often computer commands? called the (1) Arithmetic unit (2) Logic unit (1) clock (2) nerve centre (3) Both ‘1’ and ‘2’ (4) Control unit (3) Both ‘1’ and ‘2’ (4) IC 18 Learn, Revise & Practice ~ Computer Awareness 42. Who invent the first microprocessor? 52. The CPU and memory are located in which (1) Vint Cerf (2) Terence Percival of the following devices? (3) John Mauchly (4) Ted Hoff [IBPS Clerk Mains 2017] (1) Motherboard (2) Expansion board 43. A microprocessor is the brain of the (3) Storage device (4) Output device computer and is also called a [RBI Grade B 2014] (5) System unit (1) microchip (2) macrochip 53. The main circuit board in the computer that (3) macroprocessor (4) calculator connects the parts of the computer is the (5) software [SBI Clerk 2015] 44. Microprocessors can be used to make (1) motherboard (2) father board [SBI Clerk 2010] (3) match board (4) hard drive (1) computer (2) digital system (5) special board (3) calculators (4) All of these 54. Personal computers use a number of chips (5) None of these mounted on a main circuit board. What is 45. The microprocessor is made up of millions of the common name for such boards? (1) registers (2) transistors (1) Daughterboard (2) Motherboard (3) microchips (4) program counter (3) Broadboard (4) None of these 46. The microprocessor of a computer 55. Which of the following are the components (1) does not understand machine language that reside on motherboard? (2) understands machine language and high level (1) CMOS battery (2) Fan language (3) PCI slot (4) All of these (3) understands only machine language (4) understands only high level languages 56. The communication line between CPU, memory and peripherals is called a 47. Memory unit that communicates directly [Union Bank of India Clerk 2011] with the CPU is called the (1) bus (2) line (1) main memory (2) secondary memory (3) media (4) All of these (3) auxiliary memory (4) register (5) None of these 48. CPU retrieves its data and instructions from 57............. connects components inside the (1) secondary memory (2) auxiliary memory motherboard like CPU and system memory. (3) main memory (4) All of these (1) Data bus (2) Address bus 49. Which computer memory is used for storing (3) Internal bus (4) External bus programs and data currently being 58. The address of I/O device or memory is processed by the CPU? carried by the (1) Mass memory (2) Internal memory (1) data bus (2) expansion bus (3) Non-volatile memory (4) PROM (3) address bus (4) system bus 50. The I/O processor has a direct access to …… 59. A physical connection between the and contains a number of independent data microprocessor memory and other parts of channels. the micro computer is known as (1) main memory (2) secondary memory (1) path (2) address bus (3) cache (4) flash memory (3) route (4) All of these 51. The word ‘computer’ usually refers to the 60. The read/write line belongs to central processing unit plus (1) the data bus (2) the control bus (1) external memory (2) internal memory (3) the address bus (4) CPU bus (3) input devices (4) output devices Computer Architecture 19 61. The name of the location of a particular 68. What is the full form of DMA? piece of data is its (1) Direct Memory Access (1) address (2) Dynamic Memory Access (2) memory name (3) Direct Metho Access (3) storage (4) Double Memory Access (4) data location 69. The machine cycle includes 62. Which of the following is used to connect (1) fetch (2) decode (3) execute (4) store the different external devices? (e) None of these (1) Address bus (2) Data bus 70. When machine instructions are being executed (3) Control bus (4) External bus by a computer, the instruction phase followed 63. Which is not an integral part of computer? by the execution phase is referred to as [SBI Clerk 2012] (1) program cycle (2) machine instruction (1) CPU (2) Mouse (3) instruction cycle (4) task cycle (3) Monitor (4) UPS (5) None of these 71........ is the process of carrying out commands. (1) Fetching (2) Storing 64. A device that not only provides surge (3) Decoding (4) Executing protection, but also furnishes the computer 72. The processor must have two inputs with battery backup power during a power (1) instructions and data outage is [IBPS RRB PO Mains 2017] (2) information and data (1) Battery strip (2) UPS (3) input and output (3) Surge strip (4) USB (4) CPU and instructions (5) Memory 73.............. defines the parameters of the action 65. A temporary storage area, attached to the and depends on the operation. CPU, for I/O operations is a (1) Op-code (2) Operand (1) chip (2) buffer (3) instructions (4) Data (3) register (4) core 74. Pipeline strategy is called implement 66. To measure the speed of the processor,..... is (1) instruction execution used. (1) processing speed (2) clock speed (2) instruction prefetch (3) memory (4) unit (3) instruction decoding (4) instruction manipulation 67. A uniform interval of CPU time allocated for use in performing a task is known as 75. On the motherboard, the connection points (1) real time (2) seek time for chips are referred to as (3) down time (4) time slice (1) slots (2) sockets (3) ports (4) lines ANSWERS 1. (5) 2. (1) 3. (1) 4. (1) 5. (2) 6. (1) 7. (3) 8. (1) 9. (1) 10. (5) 11. (2) 12. (2) 13. (2) 14. (4) 15. (3) 16. (3) 17. (1) 18. (3) 19. (3) 20. (2) 21. (4) 22. (4) 23. (1) 24. (1) 25. (2) 26. (2) 27. (4) 28. (1) 29. (1) 30. (5) 31. (1) 32. (4) 33. (3) 34. (4) 35. (1) 36. (1) 37. (3) 38. (5) 39. (4) 40. (1) 41. (2) 42. (4) 43. (1) 44. (4) 45. (2) 46. (3) 47. (1) 48. (3) 49. (2) 50. (1) 51. (2) 52. (1) 53. (1) 54. (2) 55. (4) 56. (1) 57. (3) 58. (3) 59. (2) 60. (2) 61. (1) 62. (4) 63. (4) 64. (2) 65. (2) 66. (2) 67. (4) 68. (1) 69. (5) 70. (3) 71. (4) 72. (1) 73. (2) 74. (2) 75. (2)  C H A P T E R 03 COMPUTER HARDWARE Computer hardware refers to the physical components of a computer that can be seen and touched by the user. By the use of these hardware devices, it made very easy for the computer for processing its data, store and retrieve. Hardware is one of the basic and necessary parts of a computer system. Input Devices An input device can be defined as an electro mechanical device that allows the user to feed data into the computer for analysis and storage and to give commands to the computer. The data is entered into the main memory through the input devices. They accept instructions from the user and convert the accepted instructions into the machine language. Some of the commonly used input devices are keyboard, mouse, trackball, joystick, light pen, touch screen, barcode reader, OMR, OCR, MICR, smart card reader, biometric sensor, scanner, Mic, web cam, PC card etc. which are described below. Keyboard It is one of the most common input devices. The user Function Keys can type text and command using this device. The layout of the keyboard was borrowed from the regular typewriter with some additional keys. Keyboard is used to enter data or information in a computer system, which may be in numeric form or alphabetic form. When key is pressed, keyboard interacts with a Alphanumeric Cursor Control Numeric keyboard controller and keyboard buffer. Keys Keys keypad Keyboard controller stores the code of pressed key in Keyboard keyboard buffer. There are different types of keyboard such as QWERTY, DVORAK and AZERTY. Computer Hardware 21 Types of Keys on Keyboard (iv) Backspace Key It is used to erase The keys are categorised under the following groups anything typed. 1. Alphanumeric Keys include the alphabet (v) Delete Key It is used to erase keys (A, B, C,..., Z) and number keys information from the computer’s memory (0, 1, 2, 3,..., 9). and characters on the screen. 2. Numeric Keys are located at the right hand (vi) Caps Lock Key It is used to type the side of the keyboard. They consist of digits alphabet in capital letters. It enables or and mathematical operators. disables all the letters from being typed in capital letters. When this key is enable, 3. Function Keys are the programmable keys, the alphabet would be in capital letters i.e. the programs can assign some specific and when it is disabled, the alphabet actions. They are numbered from F1 to F12. would be in small letters. 4. Cursor Control Keys include four direc- (vii) Num Lock Key It is used to enable and tional (left, right, up, down) arrow keys that disable the numeric keypad. are arranged in a inverted T formation (viii) Windows Key It is used to open the between the alphanumeric and numeric keypad. Start menu. Above the arrow keys there are four more keys to control the cursor. These are as follows (ix) Spacebar Key It provides a space between two words. It is the longest key (i) Home It is used to return the cursor to on the keyboard. the beginning of the line or the beginning (x) Tab Key It is used to move the cursor of a document. over to the right to a pre-set point. In Word (ii) End It moves the cursor to the end of line. document, tab is used to indent a paragraph. (iii) Page Up When it is pressed, the page view will be moved up one page and Tit-Bits cursor goes to the back page. QWERTY keyboard contains total 104 keys. (iv) Page Down When it is pressed, the Caps Lock and Num Lock keys are called as page view will be moved down one page ‘toggle keys’ because when pressed, they toggle and cursor goes to the next page. or change their status from one state to another. Shift, Ctrl and Alt keys are also known as modifier 5. Other Keys A keyboard contains some other keys. keys such as follows (i) Control Key It performs a special Pointing Devices operation with the combination of other A pointing device is used to communicate with keys. the computer by pointing to the locations on the (ii) Enter Key It is used to finish an entry monitor. Movements of the pointing device are and begin the new entry in a document. echoed on the screen by movements of the Enter key is an alternative to press ok button. pointer. Some commonly used pointing devices (ii) Shift Key Some keys on the keyboard are mouse, trackball, joystick, light pen, touch like numeric keys have a symbol printed screen, etc. which are described below : on their upper portion. Shift key is used to print these symbols. This key is also called Mouse combination key. It is a small handheld device having two buttons on its upper side and also has a small wheel (iii) Escape Key (Esc) It allows a user to between these buttons. It is a pointing device cancel or abort operations, which are which provides a means to input data and executing at present. It opens Start menu commands in graphic form by selecting through with the combination of Ctrl key. moving an arrow called pointer on monitor. 22 Learn, Revise & Practice ~ Computer Awareness The mouse may be used to position the cursor on Light Pen screen, move an object by dragging or select an It is a handheld electro-optical pointing device, object by clicking. Mouse was invented by Douglas which is used for making drawings, graphics and Engelbart at Stanford Research Center in 1963. for menu selection. The pen contains a photocell There are three types of mouse as follows in a small tube. It senses the light from the screen (i) Wireless mouse when it becomes closer and generates a pulse. It is used to especially in Personal Digital Assistants (ii) Mechanical mouse (PDA). It is very useful in identifying a specific (iii) Optical mouse location on the screen. However, it does not There are four actions of mouse as follows provide any information when it held over a 1. Click or Left Click It selects an item on the blank part of the screen. screen. Touch Screen 2. Double Click It is used to open a document It is an input device that accepts input when the or program. user places a fingertip on the computer screen. 3. Right Click It displays a list of commands Touch screens have an infrared beam that on the screen. Right clicking is used to access criss-cross the surface of screen. The ability to the properties of selected object. interact directly with a display typically indicates the presence of a touch screen. Touch screen is 4. Drag and Drop It is used to move an item generally used in applications like ATM, hospitals, on the screen. airline reservation, supermarkets, etc. Trackball It is another pointing device Trackball Barcode Reader which is an alternative to a It is an input device used for mouse. Trackball is also used reading printed barcodes to control cursor movements (Universal Product Code) and actions on a computer available on product to be sold. A screen. It is generally built barcode reader emits a beam of in laptop, since there is no space for the mouse to light which reflects off the move on the laptop. Trackball is used on barcode image. A light sensitive Barcode Reader CAD/CAM workstations and sometimes seen on detector in the barcode reader computerised special purpose workstations such identifies the barcode image by recognising as radar consoles in an air-traffic control room special bars at both the ends of the image. and sonar equipment on a ship or submarine. A perfect example of a barcode reader, use in a Joystick super market where barcode scanner reads the It is a device that moves in all price of a product. A barcode is a machine directions and controls the readable representation of information in the movement of the cursor. Joysticks form of stripes of dark and light ink. are used in flight simulators, CAD/ CAM system, etc. A joystick is similar to a mouse except that the movement of 5050574807678 cursor on screen stops working as Joystick Barcode soon as user stop moving the Optical Mark Reader (OMR) mouse. But with a joystick, the pointer continues OMR is also known as Optical Mark Recognition. moving in the previously pointing direction. It is the process of detecting the presence of Joystick allows movements in all directions (360°). intended marked responses. OMR is mainly used Computer Hardware 23 to detect marks on a paper. It uses a beam of light that is reflected on the paper with marks, to Smart Card Reader capture presence and absence of data (marks). It is a device which is used to access the microprocessor of a smart card. There are two Input Hopper kinds of smart cards; Memory cards and Output Microprocessor cards. Memory cards are the cards Stacker which contain only non-volatile memory storage components and some specific security logic. Microprocessor cards contain volatile memory and microprocessor components. Optical Mark Reader The card is made-up of plastic generally PVC. The OMR interprets the pattern of marks into a Smart cards are used in large companies and data record and sends this to the computer for organisations for stronger security authentication. storage, analysis and reporting. OMR is widely used to read the answer of objective type tests, Biometric Sensor voting applications and other evaluation studies. It is a device which recognises physical or behavioural traits of the individual. Biometric Optical Character Recognition sensors are used for marking attendance of (OCR) employees/students in organisations/institutions. OCR is a technique for the scanning of a printed As biometric sensors are working with accuracy page, translating it and then using the OCR software so these are widely used in security purpose also. to recognise the image as ASCII text that is editable. It translates the array of dots into text that the computer can interpret as words and letters. OCR is widely used technique for acquiring the textual data from image. It is used in many applications Biometric Sensor such as telephone bills, electricity bills, insurance premium, etc. OCR technology is being developed Scanner for greater accurate recognition and is also known It is used to convert the data and image on paper as Intelligent Character Recognition (ICR). into the digital form. Scanner is an optical input device and uses light as an input source to convert Magnetic Ink Character an image into an electronic form that can be stored on the computer. Scanners can be used for Recognition (MICR) storing the documents in their original form that MICR reads the characters by examining their can be modified and manipulated later on. shapes in a matrix form and the information is Scanner stores images in both gray scale and color then passed on to the computer. The characters mode. The most common types of scanners are as are printed using a special ink, which contains follows iron particles that can be magnetised. (i) Handheld Scanners They are very small in size which can be held in a hand. These are less expensive and less wide. Hence, in order to scan a single page image, multiple passes are required. But their handiness is a major advantage of handheld scanner. (ii) Flatbed Scanners They are large and more Format of a Cheque expensive scanners that create high quality images. It is generally used in banks to process the Flatbed scanners have a flat surface on which cheques for recognising the magnetic encoding the printed image to be scanned, is placed. numbers printed at the bottom of a cheque. These scanners can scan a page in a single pass. 24 Learn, Revise & Practice ~ Computer Awareness (iii) Drum Scanners They are medium size a notebook or laptop computer. Probably the most scanners with a rolling drum. The sheet is fed common use of a PC card is the tele- through the scanners so that the drum rolls communications modem for notebook computers. over the entire sheet to be scanned (just as the sheets are fed in a fax machine). Output Devices An