BMG 101 Introduction to Computers & Internet PDF

Yashwantrao Chavan Maharashtra Open University Digital Art B. Sc. in Media Graphics and Animation BMG 101: Introduction to Computers & Internet YASHWANTRAO CHAVAN MAHARASHTRA OPEN UNIVERSITY T97:B.Sc. in Media Graphics and Animation [B.Sc. (MGA)] 2010 Pattern: Course code: BMG101 INTRODUCTION TO COMPUTERS AND INTERNET YASHWANTRAO CHAVAN MAHARASHTRA OPEN UNIVERSITY Dnyangangotri, Near Gangapur Dam, Nashik 422 222, Maharshtra YASHWANTRAO CHAVAN MAHARASHTRA OPEN UNIVERSITY Vice-Chancellor : Prof. (Dr.) E. Vayunandan School of Continuing Education School Council Dr Rajendra Vadnere, Dr Surya Gunjal Smt Jyoti Shetty. Chairman, Director Professor Principal School of Continuing Education School of Agriculture Science S.P. More College, Panwel YCMOU, Nashik YCMOU, Nashik Dr Abhay Patil Dr Jaydeep Naikam Dr Pranod Khandare Assistant Professor Professor Assistant Professor School of Health Science School of Continuing Education School of Computer Science YCMOU, Nashik YCMOU, Nashik YCMOU, Nashik Shri Asvin Sonone, Dr Rucha Gujar Dr Latika Ajbani Associate Professor Assistant Professor Assistant Professor FTII Pune School of Continuing Education School of Commerce & Mgt Shri P V Patil YCMOU, Nashik YCMOU, Nashik Dy District Voc Education & Shri Ram Thakar Dr Sunanda More Training Officer, Assistant Professor Assistant Professor DVET, Nashik School of Continuing Education School of Science & Tech. Shri Shankar Goenka YCMOU, Nashik YCMOU, Nashik Country Head Wow Fafctors Ind Pvt Ltd, Delhi Author Content Editor Instruct. Tech. Editor and Coordinator (Dev.) Madhura Bhagat (all but Unit 10) Ravi H Tikate (all but Unit 10) Dr Rajendra Vadnere MCE Society's College of Visual MCE Society's College of Visual Director Effect Design and Arts, Pune Effect Design and Arts, Pune School of Continuing Education Shailaja M. Pimputkar (Unit 10) Santosh Raskar (Unit 10) Y.C.M.O. U. Srajan Institute of Multimedia, Srajan Institute of Multimedia, Nashik Gaming and Animation, Pune Gaming and Animation, Pune Production Shri. Anand Yadav Manager, Print Production Centre, YCMOU, Nashik © 2017, Yashwantrao Chavan Maharashtra Open Univesity, Nashik  First Publication : June 2017  Publication No. :  Typesetting :  Printer :  Published by : Dr. Dinesh Bhonde, Registrar, Y. C. M. Open University, Nashik - 422 222. B-16-17-93 (BTH331) BMG 101: Introduction to Computers and Internet Credit 1: Unit 1 : Introduction to Computers Unit 2 : Computer Organisation Unit 3 : Software Applications Credit 2: Unit 4 : Input to Computers Unit 5 : Data Processing Unit 6 : Output Devices Credit 3: Unit 7 : Data Storage Unit 8 : Internet Basics Credit 4: Unit 9 : The Study of Internet Unit 10 : Microsoft Word 2007 CONTENTS UNIT 1: INTRODUCTION TO COMPUTERS..................................................................... 17 1.0 BEFORE WE BEGIN........................................................................................................................... 17 1.1 UNIT OBJECTIVES............................................................................................................................. 17 1.2 What is a computer?........................................................................................................................ 17 1.3 What makes a computer powerful?................................................................................................. 18 1.3.1 Speed:............................................................................................................................................. 18 1.3.2 Reliability:....................................................................................................................................... 19 1.3.3 Accuracy.......................................................................................................................................... 19 1.3.4 Storage............................................................................................................................................ 19 1.3.5 Diligence.......................................................................................................................................... 19 1.3.6 Versatility........................................................................................................................................ 19 1.3.7 Power of Remembering.................................................................................................................. 19 1.3.8 No “intelligence”............................................................................................................................. 19 1.3.9 No Feelings...................................................................................................................................... 20 1.4 THE HISTORY OF COMPUTERS.......................................................................................................... 20 1.4.1 Types of calculating Machines........................................................................................................ 20 1.4.2 Napier’s Bones................................................................................................................................ 20 1.4.3 Slide Rule......................................................................................................................................... 22 1.4.4 Pascal’s adding & subtracting machines......................................................................................... 23 1.4.5 Leibniz’s multiplication and division machines............................................................................... 24 1.4.6 Babbage’s analytical engine............................................................................................................ 26 1.4.7 Mechanical calculator..................................................................................................................... 27 1.5 Electrical Calculator......................................................................................................................... 28 BMG101: Introduction to Computers Page 1 1.5.1 Modern Electronic Calculator......................................................................................................... 29 1.6 Computer Generations..................................................................................................................... 32 1.6.1 First generation computers (1939-1954): Vacuum Tube................................................................ 32 1.6.2 Second generation computers (1954-1959): Transistors:.............................................................. 33 1.6.3 Third generation computers (1959-1971): IC................................................................................. 34 1.6.4 Fourth generation (1939-1954): Microprocessors.......................................................................... 36 1.6.5 Fifth generation computers (1991 & beyond)................................................................................ 36 1.7 Types of Computers......................................................................................................................... 38 1.8 Workstations............................................................................................................................... 39 1.9 Mainframe.................................................................................................................................. 40 1.9.1 Differences between Mainframe and supercomputers.................................................................. 42 1.9.2 Characteristics of Mainframe.......................................................................................................... 42 1.10 Supercomputer.............................................................................................................................. 43 1.11 Servers........................................................................................................................................... 45 Hardware requirement............................................................................................................................ 46 1.12 Summary........................................................................................................................................ 47 1.13 KEY TERMS..................................................................................................................................... 47 1.14 END QUESTIONS............................................................................................................................. 48 1.15 REFERENCES................................................................................................................................... 48 UNIT 2: COMPUTER ORGANIZATION.............................................................................. 50 2.0 BEFORE WE BEGIN........................................................................................................................... 50 2.1 Unit Objectives................................................................................................................................ 50 2.2 Basic Computer Operations............................................................................................................. 50 2.2.1. INPUT............................................................................................................................................. 53 2.2.2 PROCESSING.................................................................................................................................... 54 BMG101: Introduction to Computers Page 2 2.2.3 CONTROL......................................................................................................................................... 55 2.2.4 OUTPUT.......................................................................................................................................... 55 2.2.5 STORAGE........................................................................................................................................ 56 2.3 Functional Unit................................................................................................................................ 56 2.3.1 Arithmetic and Logic Unit (ALU)...................................................................................................... 56 2.3.2 Control Unit.................................................................................................................................... 57 2.3.3 Central Processing Unit (CPU)......................................................................................................... 57 2.4 MEMORY SYSTEM IN A COMPUTER................................................................................................. 58 2.5 CAPACITY OF PRIMARY MEMORY.................................................................................................... 59 2.5.1. Primary Memory / Volatile Memory:............................................................................................. 59 2.5.2 Secondary Memory / Non Volatile Memory:.................................................................................. 59 2.6 SECONDARY STORAGE..................................................................................................................... 60 2.6.1 Magnetic Tape................................................................................................................................ 61 2.6.2 Magnetic Disc.................................................................................................................................. 61 2.6.3 Floppy disc...................................................................................................................................... 61 2.6.4 Optical Disc..................................................................................................................................... 61 2.7 SUMMARY....................................................................................................................................... 62 2.8 KEY TERMS....................................................................................................................................... 63 2.9 END QUESTIONS.............................................................................................................................. 63 2.10 REFERENCES................................................................................................................................... 64 UNIT 3: SOFTWARE APPLICATIONS................................................................................ 65 3.0 BEFORE WE BEGIN........................................................................................................................... 65 3.1 UNIT OBJECTIVES............................................................................................................................. 66 3.2 WORD PROCESSING......................................................................................................................... 66 3.2.1 MAIN FEATURES OF WORD PROCESSING....................................................................................... 66 BMG101: Introduction to Computers Page 3 3.2.1 The ‘Create File’ Menu.................................................................................................................... 68 3.2.2 The Format Menu........................................................................................................................... 69 3.2.3 The Print Option.............................................................................................................................. 69 3.3 SPREADSHEETS................................................................................................................................ 71 3.4 HTML EDITOR................................................................................................................................... 73 3.5 DESKTOP PUBLISHING...................................................................................................................... 74 3.6 TYPES (LEVELS) OF SOFTWARE......................................................................................................... 74 3.6.1 System Software............................................................................................................................. 74 3.6.2 Programming Software................................................................................................................... 75 3.6.3 Application Software....................................................................................................................... 75 3.7 DATABASE........................................................................................................................................ 77 3.8 QUERIES........................................................................................................................................... 84 3.9 GRAPHICS PROGRAMS..................................................................................................................... 85 3.10 DRAWING PROGRAMS................................................................................................................... 88 3.11 PAINT............................................................................................................................................. 89 3.11.1 History........................................................................................................................................... 89 3.11.2 Windows 7 and later..................................................................................................................... 90 3.11.3 Future............................................................................................................................................ 90 3.11.4 Features........................................................................................................................................ 90 3.11.5 Support for indexed palettes........................................................................................................ 91 3.12 Animation and Video Programs..................................................................................................... 92 3.12.1 Computer Animation................................................................................................................... 92 List of 2D animation software.................................................................................................................. 93 List of 3D animation programs................................................................................................................. 95 3.12.2 Computer-assisted vs. computer-generated................................................................................ 96 BMG101: Introduction to Computers Page 4 3.12.3 Video Programs............................................................................................................................. 97 3.12.4 List of video editing software........................................................................................................ 97 3.13 Presentation Programs.................................................................................................................. 99 3.13.1 Features........................................................................................................................................ 99 3.14 Communication Programs............................................................................................................ 100 3.14.1 History......................................................................................................................................... 100 3.14.2 Chat............................................................................................................................................. 101 3.15 The File Transfer Protocol (FTP)................................................................................................... 101 3.16 Chat and Instant Messaging......................................................................................................... 102 3.16.1 Chatiquette................................................................................................................................. 103 3.16.2 Instant messaging (IM)............................................................................................................... 103 3.17 Project Management Programs.................................................................................................... 104 3.17.1 Predecessors............................................................................................................................... 104 3.17.2 Emergence of the ‘project management’ term and modernized techniques............................ 105 3.17.3 The first project management products and associations.......................................................... 105 3.17.4 SaaS and cloud-based project management software............................................................... 105 3.17.5 Tasks and activities..................................................................................................................... 106 3.17.6 Types........................................................................................................................................... 107 3.18 Integrated Software..................................................................................................................... 108 3.19 Summary...................................................................................................................................... 109 3.20 Key Terms.................................................................................................................................... 111 3.21 End Questions.............................................................................................................................. 114 3.22 References................................................................................................................................... 115 UNIT 4: INPUT TO COMPUTERS...................................................................................... 116 4.0 BEFORE WE BEGIN......................................................................................................................... 116 BMG101: Introduction to Computers Page 5 4.1 UNIT OBJECTIVES........................................................................................................................... 116 4.2 TYPES OF INPUT HARDWARE......................................................................................................... 116 4.3 KEYBOARD..................................................................................................................................... 117 4.3.1 Types of Keyboards....................................................................................................................... 117 4.3.2 Keyboard Layout........................................................................................................................... 119 4.3.3 Key Types...................................................................................................................................... 120 4.4 POINTING DEVICES......................................................................................................................... 122 4.4.1 Mouse........................................................................................................................................... 123 4.4.2 Trackball........................................................................................................................................ 124 4.4.3 Touchpad...................................................................................................................................... 124 4.4.4 Light Pens...................................................................................................................................... 124 4.4.5 Touch Screens............................................................................................................................... 124 4.4.6 Digitizers and Graphic Tablet........................................................................................................ 124 4.5 GAME DEVICES............................................................................................................................... 125 4.6 POINT-OF-SALE (POS) TERMINAL................................................................................................... 127 4.7 WHAT IS MULTIMEDIA?................................................................................................................. 127 4.7.1 Multimedia Tools.......................................................................................................................... 128 4.7.2 Elements of Multimedia................................................................................................................ 129 4.8 SOUND INPUT................................................................................................................................ 133 4.9 VOICE INPUT.................................................................................................................................. 133 4.9.1 Changing Voice to Data................................................................................................................. 134 4.9.2 Types of Voice Recognition Systems............................................................................................. 134 4.10 VIDEO INPUT................................................................................................................................ 135 4.11 DATA AUTOMATION.................................................................................................................... 135 4.12 GENERAL DEVICES........................................................................................................................ 136 BMG101: Introduction to Computers Page 6 4.13 OPTICAL CHARACTER RECOGNITION SOFTWARE.......................................................................... 137 4.14 SUMMARY................................................................................................................................... 138 4.15 END QUESTIONS........................................................................................................................... 139 UNIT 5 DATA PROCESSING............................................................................................... 141 5.0 BEFORE WE BEGIN......................................................................................................................... 141 5.1 UNIT OBJECTIVES........................................................................................................................... 141 5.2 WHAT IS PROCESSING?.................................................................................................................. 141 5.3 processing digital data................................................................................................................... 141 5.4 DIGITAL codes................................................................................................................................ 143 5.5 parity............................................................................................................................................. 144 5.6 machine cycles & speed................................................................................................................. 145 5.6.1 Components of a simple Digital System....................................................................................... 146 5.6.2 How does the System execute a program?.................................................................................. 146 5.6.3 Initiating the cycle......................................................................................................................... 147 5.7 memory addresses......................................................................................................................... 149 5.7.1 Physical addresses........................................................................................................................ 149 5.7.2 Logical addresses.......................................................................................................................... 150 5.7.3 Contents of each memory location............................................................................................... 150 5.7.4 Memory Address and size of Memory.......................................................................................... 150 5.8 processor speed............................................................................................................................. 151 5.8.1 Historical milestones and current records.................................................................................... 151 5.9 physical components..................................................................................................................... 152 5.9.1 Microprocessor............................................................................................................................. 152 5.9.2 Random-access memory............................................................................................................... 153 5.10 motherboard............................................................................................................................... 155 BMG101: Introduction to Computers Page 7 5.10.1 Design......................................................................................................................................... 156 5.11 INDUSTRY STANDARD ARCHITECTURE (ISA)................................................................................. 157 5.11.1 8-Bit ISA Slots.............................................................................................................................. 157 5.11.2 Peripheral Component Interconnect (PCI) Slots......................................................................... 157 5.11.3 Memory Slots.............................................................................................................................. 159 5.12 CONNECTORS............................................................................................................................... 160 5.12.1 RAM Connectors......................................................................................................................... 160 5.12.2 Input-Output Connectors............................................................................................................ 160 5.12.3 Power connections..................................................................................................................... 161 5.13 PROCESSOR SOCKET..................................................................................................................... 162 5.14 summary...................................................................................................................................... 163 5.15 key terms..................................................................................................................................... 164 5.13 end questions.............................................................................................................................. 164 5.14 REFERENCES................................................................................................................................. 165 UNIT 6: OUTPUT DEVICES................................................................................................. 167 6.0 BEFORE WE BEGIN......................................................................................................................... 167 6.1 UNIT OBJECTIVES........................................................................................................................... 167 6.2 forms of output.............................................................................................................................. 167 6.2.1 Display devices.............................................................................................................................. 168 6.2.2 Input/output................................................................................................................................. 168 6.2.3 Types of output............................................................................................................................. 168 6.2.4 Graphics (Visual)........................................................................................................................... 168 6.2.5 Tactile............................................................................................................................................ 169 6.2.6 Audio............................................................................................................................................. 169 6.2.7 Examples of Output Devices......................................................................................................... 169 BMG101: Introduction to Computers Page 8 6.3 printer............................................................................................................................................ 170 6.3.1 Types of printers........................................................................................................................... 170 6.3.2 Technology.................................................................................................................................... 171 6.3.3 Attributes...................................................................................................................................... 177 6.4 screen DISPLAY.............................................................................................................................. 179 Technologies.......................................................................................................................................... 179 6.4.1 Cathode ray tube.......................................................................................................................... 179 6.4.2 Liquid crystal display..................................................................................................................... 181 6.4.3 Organic light-emitting diode (OLED)............................................................................................. 182 Measurements of performance............................................................................................................. 182 Additional features................................................................................................................................ 185 6.5 Speakers........................................................................................................................................ 186 6.6 summery........................................................................................................................................ 188 6.7 key terms....................................................................................................................................... 188 6.8 REFERENCES................................................................................................................................... 189 UNIT 7: DATA STORAGE.................................................................................................... 191 7.0 INTRODUCTION.............................................................................................................................. 191 7.1 UNIT OBJECTIVES:.......................................................................................................................... 191 Cylinder Head Sector method................................................................................................................ 195 UNIT 8: INTERNET BASICS................................................................................................ 212 8.0 INTRODUCTION.............................................................................................................................. 212 8.1 UNIT OBJECTIVES........................................................................................................................... 213 8.2 Introduction to the Internet........................................................................................................... 213 8.2.1 Interoperable................................................................................................................................ 214 8.2.2 Packet Switching........................................................................................................................... 215 BMG101: Introduction to Computers Page 9 8.2.3 Data Network................................................................................................................................ 216 8.2.4 Connecting to the Internet........................................................................................................... 217 8.2.5 Internet Services: E-Mail, Telnet and WWW................................................................................ 220 8.3 World Wide Web (WWW).............................................................................................................. 222 8.3.1 Universal Resource Locator (URL)................................................................................................. 223 8.3.2 Gopher: Its Origin.......................................................................................................................... 224 8.3.3 Stagnation of gopher.................................................................................................................... 225 8.3.4 Availability of Gopher Today......................................................................................................... 225 8.3.6 Gopher Clients.............................................................................................................................. 227 8.3.7 Gopher to HTTP Gateways............................................................................................................ 228 8.3.8 Gopher Characteristics.................................................................................................................. 228 8.3.9 Technical Details and Protocol...................................................................................................... 228 URL Links and Related Technology........................................................................................................ 230 8.3.10 Gopher Server Software............................................................................................................. 230 8.4 hiSTORY OF THE INTERNET............................................................................................................. 231 8.4.1 IP Addresses.................................................................................................................................. 233 8.4.2 Domain Name............................................................................................................................... 233 8.4.3 Need to Register Your Domain Name........................................................................................... 234 8.4.4. Repeater...................................................................................................................................... 234 8.4.5 Bridge............................................................................................................................................ 234 8.4.6 Router........................................................................................................................................... 235 8.4.7 Brouter.......................................................................................................................................... 235 8.4.8 Firewall.......................................................................................................................................... 236 8.4.9 Ethernet: Packet-filtering Firewalls............................................................................................... 238 8.4.10 Search Engine.............................................................................................................................. 243 BMG101: Introduction to Computers Page 10 8.5 SUMMARY..................................................................................................................................... 247 8.6 key terms....................................................................................................................................... 247 8.7 end questions................................................................................................................................ 248 8.8 REFERENCES................................................................................................................................... 248 UNIT 9: THE STUDY OF THE INTERNET....................................................................... 249 9.0 INTRODUCTION.............................................................................................................................. 249 9.1 UNIT OBJECTIVES........................................................................................................................... 249 9.2 WEB DIRECTORIES.......................................................................................................................... 249 9.2.1 Range of Listing............................................................................................................................. 250 9.2.2 Human-Edited Directories............................................................................................................ 250 9.2.3 Bid for Position Directories........................................................................................................... 251 9.2.4 Automated Submission of Web Directories.................................................................................. 251 9.2.5 Working of a Web Directory......................................................................................................... 251 9.3 SEARCH ENGINES BASICS............................................................................................................... 255 9.3.1 Different Search Engines............................................................................................................... 256 9.4 aLTAVISTA...................................................................................................................................... 266 9.4.1 Alta Vista Search Home Page........................................................................................................ 267 9.4.2 Searching with AltaVista............................................................................................................... 267 9.4.3 AltaVista Search Features............................................................................................................. 267 9.5 EXCITE............................................................................................................................................ 268 9.6 Hotbot........................................................................................................................................... 270 9.7 Lycos.............................................................................................................................................. 270 9.7.1 Lycos Home Page.......................................................................................................................... 271 9.7.2 Lycos Search.................................................................................................................................. 271 9.7.3 Lycos Features............................................................................................................................... 271 BMG101: Introduction to Computers Page 11 9.8 web crawler................................................................................................................................... 271 9.8.1 Overview....................................................................................................................................... 272 9.8.2 Crawling Policies........................................................................................................................... 272 9.8.3 Selection policy............................................................................................................................. 273 9.8.4Restricting followed links............................................................................................................... 273 9.8.5 URL normalization......................................................................................................................... 273 9.8.6 Path-ascending crawling............................................................................................................... 273 9.8.7 Focused crawling.......................................................................................................................... 274 9.8.8 Academic-focused crawler............................................................................................................ 274 9.8.9 Re-visit policy................................................................................................................................ 274 9.8.10 Politeness policy......................................................................................................................... 276 9.8.11 Parallelization policy................................................................................................................... 277 9.8.12 Web Crawler Architectures......................................................................................................... 277 9.9 META-SEARCH ENGINES................................................................................................................. 279 9.9.1 Advantages................................................................................................................................... 280 9.9.2 Disadvantages............................................................................................................................... 280 9.9.3 Operation...................................................................................................................................... 281 9.9.4 Spamdexing................................................................................................................................... 282 9.9.5 Example: ProFusion....................................................................................................................... 283 9.10 web portal................................................................................................................................... 284 9.10.1 History:........................................................................................................................................ 284 9.10.2 Types of Portals:.......................................................................................................................... 285 9.11 my yahoo..................................................................................................................................... 288 9.12 SEARCH strategies........................................................................................................................ 288 9.13 beyond the BASICS: THINKING CRITICALLY ABOUT WEBSITES................................................... 290 BMG101: Introduction to Computers Page 12 9.14 EVALUATION OF INFORMATION SOURCES................................................................................... 291 9.15 how to be net savvy..................................................................................................................... 292 9.16 SummAry..................................................................................................................................... 293 9.17 key terms..................................................................................................................................... 294 9.18 end questions.............................................................................................................................. 294 UNIT 10: MICROSOFT WORD XP 2007......................................................................... 295 10.0 BEFORE WE BEGIN....................................................................................................................... 295 10.1 UNIT OBJECTIVES:........................................................................................................................ 295 10.2 MICROSOFT WORD...................................................................................................................... 295 10.2.1 Title Bar....................................................................................................................................... 296 10.2.2 Menu Bar.................................................................................................................................... 296 10.2.3 Ruler............................................................................................................................................ 297 10.2.4 Different Types of Document View............................................................................................. 297 10.2.5 Area for Text............................................................................................................................... 299 10.3 imPORTANT OPTIONS.................................................................................................................. 299 10.3.3 Selecting the Text by Highlighting............................................................................................... 302 10.3.4 Choosing Menu Commands by Using the Alt Key....................................................................... 302 10.3.5 Shortcut Notations...................................................................................................................... 303 10.3.6 Starting a New Paragraph........................................................................................................... 303 10.3.7 Exiting Microsoft Word............................................................................................................... 303 10.4 MICROSOFT WORD: BASIC FEATURES.......................................................................................... 304 10.4.1 Typing and Using the Backspace Key.......................................................................................... 304 10.4.2 Delete Key................................................................................................................................... 304 10.4.3 Inserting Text.............................................................................................................................. 305 10.5 SOME BASIC FEAUTRES................................................................................................................ 309 BMG101: Introduction to Computers Page 13 10.5.1 Open File..................................................................................................................................... 309 10.5.2 Cut and Paste.............................................................................................................................. 309 10.5.3 Copy and Paste........................................................................................................................... 310 10.5.4 Spell Check.................................................................................................................................. 311 10.5.5 Find and Replace......................................................................................................................... 312 10.5.6 Font Size:..................................................................................................................................... 313 10.6 working with paragraphs............................................................................................................. 315 10.6.1 Space Before and Space After..................................................................................................... 316 10.6.2 Line Spacing................................................................................................................................ 317 10.6.3 First-Line Indent.......................................................................................................................... 317 10.6.4 Indentation................................................................................................................................. 318 10.6.5 Alignment.................................................................................................................................... 318 10.6.6 Hanging Indent............................................................................................................................ 320 10.6.7 Save File and Exit MS Word........................................................................................................ 321 10.7 TAB KEY, BUTTETING NUMBERING UNDO, REDO, PRINTING AND HELP....................................... 321 10.7.1 Tab Key........................................................................................................................................ 321 10.7.2 Bullets and Numbering............................................................................................................... 322 10.7.3 Undo and Redo........................................................................................................................... 324 10.7.4 Save File...................................................................................................................................... 325 10.7.5 File Close..................................................................................................................................... 325 10.7.6 Open New File............................................................................................................................. 325 10.7.7 Printing........................................................................................................................................ 325 10.7.8 Print Your Document.................................................................................................................. 325 10.7.9 Alternate Method: Printing by Using Short Key Command........................................................ 325 10.7.10 Alternate Method: Printing by Using the Icon.......................................................................... 326 BMG101: Introduction to Computers Page 14 10.8 tables........................................................................................................................................... 326 10.8.1 Creating a Table.......................................................................................................................... 326 10.8.2 Moving Around a Table............................................................................................................... 327 10.8.3 Entering Text into a Table........................................................................................................... 327 10.8.4 Selecting a Row and Highlighting (Marking Bold) the Text......................................................... 328 10.8.5 Right –Aligning Text.................................................................................................................... 328 10.8.6 Adding a New Row at the End of the Table................................................................................ 329 10.8.7 Adding a Row within the Table................................................................................................... 329 10.8.8 Resizing the Columns.................................................................................................................. 329 10.8.9Adding a New Column to a Table................................................................................................. 330 10.8.10 Sorting a Table.......................................................................................................................... 331 10.8.11 Sum Function............................................................................................................................ 332 10.8.12 Deleting a Row.......................................................................................................................... 332 10.8.13 Deleting a Column..................................................................................................................... 332 10.8.14 Merge Cell................................................................................................................................. 333 10.8.15 Recalculate................................................................................................................................ 333 10.8.16 Table Headings.......................................................................................................................... 333 10.8.17 Converting Text to Table........................................................................................................... 333 10.8.18. Splitting a Table....................................................................................................................... 334 10.8.19. Table Auto Format................................................................................................................... 335 10.8.20. Save File................................................................................................................................... 335 10.9 SummAry..................................................................................................................................... 336 10.10 key terms................................................................................................................................... 337 10.11 end questions............................................................................................................................ 338 10.12 REFERENCES............................................................................................................................... 338 BMG101: Introduction to Computers Page 15 BMG101: Introduction to Computers Page 16 UNIT 1: INTRODUCTION TO COMPUTERS 1.0 BEFORE WE BEGIN Computers have touched every part of our lives: the way we work, the way we learn, the way we live, even the way we play. It almost is impossible to go through a single day without encountering a computer, a device dependent on a computer, information produced by a computer, or a word that was introduced or whose meaning has changed with the advent of computers. Because of the significance of computers in today’s world, it is important to be computer literate.Being computer literate means you have knowledge and understanding of computers and their uses. A computer is an electronic machine, operating under the control of instructions stored in its own memory, that can accept data, manipulate the data according to specified rules, produce results, and store the results for future use. Computers process data to create information Data is a collection of raw unprocessed facts, figures, and symbols. Information is data that is organized, meaningful, and useful. To process data into information, a computer uses hardware and software. Hardware is the electric, electronic, and mechanical equipment that makes up a computer. Software is the series of instructions that tells the hardware how to perform tasks. 1.1 UNIT OBJECTIVES After going through this unit, you will be able to: Discuss the basic functions of a computer Explain the history of the computer Elaborate on the factorsthat make computers powerful Describe computer generations Explain mainframe Elaborate on Servers Explain the concept of Supercomputer Elaborate on Workstations 1.2 WHAT IS A COMPUTER? What is a Computer? Computer is an electronic device that is designed to work with Information. The term computer is derived from the Latin term ‘computare’, this means to calculate or programmable machine. A computer is a device that can receive, process and store data. They are used as tools in every part of society together with the Internet. Computers nowadays are complex; there are a lot of different components inside them, and they all serve different purposes. They all need to work together for the computer to work knowing how a computer works makes it easier to use a computer by being able to understand how a computer will respond. BMG101: Introduction to Computers Page 17 Fig 1.01: Parts of a Computer CHECK YOUR PROGRESS What is a computer? What does a computer do? 1.3 WHAT MAKES A COMPUTER POWERFUL? A computer is a powerful tool because it is able to perform the information processing cycle operations (input, process, output, and storage) with amazing speed, reliability, and accuracy; store huge amounts of data and information; and communicate with other computers. Computers allow users to generate correct information quickly, hold the information so it is available at any time, and share the information with other computer users. 1.3.1 Speed: It has a very speed of executing instruction. CPU of a computer can perform more than 10 million operations per second. All the instructions are executed in accordance with a clock, whose frequency is measured in Mhz. Normally, 3-4 cycles of this clock are required to execute one instruction. Recent computers have a speed of about 300 Mhz i.e one cycle of approx.3 X 10-9 Sec. This means that it can execute an instruction in about 10 nanosec (10X 10 -8 Sec). In other words it can execute 100 million instructions in one second. But the overall speed of performance of a computer decreases due to slower Input and Output devices, interfaced to CPU. BMG101: Introduction to Computers Page 18 1.3.2 Reliability: The reliability of results processed by a computer is very high. If a program is executed any number of times with the same set of data, every time the results would be the same. 1.3.3 Accuracy The accuracy of results computed by a computer is consistently high. Due to digital techniques the error is very small. The errors in computing may be due to logical mistakes by a programmer or due to inaccurate data. 1.3.4 Storage The speed with which computers can process large quantities of data/ Information, the size of input so also the output is quite large. The size of information to be stored further increases due to graphic applications. All this information is to be stored in auxiliary memory i.e Hard Disk fitted inside the computer. Hard Disks now days have a storage capacity as large as 4 GB. The size of internal primary memory (RAM) has also been increases a lot to about 64 MB. 1.3.5 Diligence A computer is free from tiredness, lack of concentration, fatigue, etc. It can work for hours without creating any error. If millions of calculations are to be performed, a computer will perform every calculation with the same accuracy. Due to this capability it overpowers human being in routine type of work. 1.3.6 Versatility Computers are capable of performing almost task provided the task can be reduced to a series of logical steps so that an appropriate program in a suitable language can be fed to a computer memory. Of course, the input and output devices should be capable of performing the desired task. Because of these capabilities, a number of processes can be automated with the help of a computer. Apart from those outlined above, computer has some other features also. They are automatic to a great extent i.e they run with very little human interference. They can work endless at the same level of efficiency and productivity. Modern computers are becoming more and more user friendly i.e computer itself helps the user at every stage. Visual display, limited but effective use of natural language like English and appropriate software have made it very easy to operate computers 1.3.7 Power of Remembering Computer has the power of storing any amount of information or data. Any information can be stored and recalled as long as you require it, for any numbers of years. It depends entirely upon you how much data you want to store in a computer and when to lose or retrieve these data. 1.3.8 No “intelligence” BMG101: Introduction to Computers Page 19 Computer is a dumb machine and it cannot do any work without instruction from the user. It performs the instructions at tremendous speed and with accuracy. It is you to decide what you want to do and in what sequence. So a computer cannot take its own decision as you can. 1.3.9 No Feelings It does not have feelings or emotion, taste, knowledge and experience. Thus it does not get tired even after long hours of work. It does not distinguish between users. CHECK YOUR PROGRESS What are various specific features which the computers enjoy over human beings? What is meant by diligence in reference to the features of computers Explain how computers are versatile 1.4 THE HISTORY OF COMPUTERS Abacus is known to be the first mechanical calculating device, which was used to be performed addition and subtraction easily and speedily. Abacus is made up of wooden frame in which rod where fitted across with rounds beads sliding on the rod. It id dividing into two parts called ‘Heaven’ and ‘Earth’. Heaven was the upper part and Earth was the lower one. Thus any no. can be represented by placing the beads at proper place. 1.4.1 Types of calculating Machines The first step in the direction of automatic calculation was taken in 1623, when the German astronomer Wilhelm Schickard (1592‑1635) constructed his "calculating clock", as he called it. This machine was capable of executing all four basic arithmetical operations: addition and subtraction it could perform purely mechanically, while multiplication and division required as well several interventions by the operator between entering the numbers and reading off the result. They can be divided into two categories- Adding Machines Calculating Machines 1.4.2 Napier’s Bones Napier's bones, also called Napier's rods, are numbered rods which can be used to perform multiplication of any number by a number 2-9. By placing "bones" corresponding to the multiplier on the left side and the bones corresponding to the digits of the multiplicand next to it to the right, and product can be read off simply by adding pairs of numbers (with appropriate carries as needed) in the row determined by the multiplier. This process was published by Napier in 1617 a book titled BMG101: Introduction to Computers Page 20 Rabdologia, so the process is also called rabdology. The 'bones' consist of a set of rectangular rods, each marked with a counting number at the top, and the multiples of that number down their lengths. Multiples are written across the diagonal of a square. Fig 1.02: Napier’s Bones To multiply one number by another you need to align the digits as they are positioned in the given number against the row of multiples as shown. You look for a number that you are multiplying your large number by and read the results from right to left by adding the digits in each square diagonally in the appropriate row. Multiplication is thus reduced to addition. For example: to multiply 249 by 9, you need first to position your rods to get the first rod followed by rods beginning with 2, 4, and 9 aligned (or put into a frame). Fig 1.03: Napier’s bone’s exaples BMG101: Introduction to Computers Page 21 Add the numbers diagonally in the 9 th row and look from right to left: 1. And then diagonally 6+8=14 - write 4 and remember 1 to take to the next row 8+3=11, add 1 from thee previous and remember 1 to take to the next row 1 and add one from the previous row row. Hence the result is 2241. You can do incredibly long calculations using Napier bones. 1.4.3 Slide Rule The slide rule is actually made of three bars that are fixed toge together. ther. The sliding center bar is sandwiched by the outer bars which are fixed with respect to each other. The metal "window" is inserted over the slide rule to act as a place holder. A cursor is fixed in the center of the "window" to allow for accurate readings. The scales (A-D) D) are labeled on the left-hand left hand side of the slide rule. The number of scales on a slide rule vary depending on the number of mathematical functions the slide rule can perform. Multiplication and division are performed using the C and D scales. Square and square root are performed with the A and B scales. The numbers are marked according to a logarithmic scale. Therefore, the first number on the slide rule scale (also called the index) is 1 because the log of zero is one. Fig 1.04: An example of slide rule The slide rule, also known colloquially in the United States as a slipstick, is a mechanical analog computer. The slide rule is used primarily for multiplication and division, and also for functions such as exponents, roots, logarithms and trigonometry, but typically not for addition or subtraction. Though similar in name and appearance to a standard ruler, the slide rule is not meant to be used for measuring length or drawing straight lines. BMG101: Introduction to Computers Page 22 Slide rules exist in a diverse range of styles and generally appear in a linear or circular form with a standardized set of markings (scales) essential to performing mathematical computations. Slide rules manufactured for specialized fields such as aviation or finance typically feature additional scales that aid in calculations common to those fields. At its simplest, each number to be multiplied is represented by a length on a sliding ruler. As the rulers each have a logarithmic scale, it is possible to align them to read the sum of the logarithms, and hence calculate the product, of the two numbers. The Reverend William Oughtred and others developed the slide rule in the 17th century based on the emerging work on logarithms by John Napier. Before the advent of the electronic calculator, it was the most commonly used calculation tool in science and engineering. The use of slide rules continued to grow through the 1950s and 1960s even as computers were being gradually introduced; but around 1974 the handheld electronic scientific calculator made them largely obsolete and most suppliers left the business. 1.4.4 Pascal’s adding & subtracting machines Consequently, the possibility of mechanising arithmetic was first demonstrated in public in 1642, when Blaise Pascal (1623‑1662), the great French mathematician and philosopher, then only nineteen years old and totally unaware of the achievements of his predecessor Schickard, constructed his celebrated "Pascaline". He was spurred to invent it by the interminable calculations which he made for the accounts of his father (whom Richelieu had appointed Intendant of Rouen), which he carried out by means of an abacus with counters. The principal characteristic of Pascal's machine was its facility for automatic carrying. This was achieved by the use of a series of toothed wheels, each numbered from 0 to 9, linked (by weighted ratchets) in such a way that when one wheel completed a revolution the next wheel advanced by one step. The prototype had five wheels, and so could handle five‑digit numbers; later versions had six or eight wheels. [Numbers to be added were entered by turning setting‑wheels on the front of the machine, which were linked by a series of crown gears to the wheels which displayed the results. Addition was done by first turning the setting‑wheels by hand according to the digits of one number, and then turning them according to the digits of the other. Transl.] Essentially, this was an adding machine which could not run in reverse, so that direct subtraction was impossible. Nevertheless, it was possible to perform subtraction by the process of adding the decimal complement of the number to be subtracted. The calculator had metal wheel dials that were turned to the appropriate numbers using a stylus; the answers appeared in boxes in the top of the calculator. Blaise’s calculated was a polished brass box, about 350mm by 125 mm by 75mm. It was compact enough to carry. On the top was a row of eight movable dials, with numerals from 0 to 9, which is use to add a column of up to eight figures. The right-hand dial represented deniers, the next dial represented sous, and the remainder were for livres, of modern francs. The machines could be used equally well for pence, shilling, and pounds. BMG101: Introduction to Computers Page 23 The machine could add, subtract, multiply, and divide. Multipl Multiplication ication and division were somewhat difficult to do, by performing multiplication and division by repeated addition and subtraction. In fact the machine could really only add, because subtractions were performed using complementary techniques, in which the number to be subtracted is first converted into its complement, which is then added to the first number. These two operations were made possible if one considered multiplication as a form of addition and division a form of subtraction. For example, to multiply iply 1234 by 567 one would register 1234 seven times beginning with the dial on the right. The next dial would be used to register 1234 six times. Finally, the next dial would register 1234 five times. Pull the handle and the answer would appear. Interesti Interestingly ngly enough, modern computers employ similar complement techniques. There were problems faced by Pascal in the design of the calculator which were due to the design of the French currency at that time. There were 20 sols in a livre and 12 deniers in a sol. The system remained in France until 1799 but in Britain a system with similar multiples lasted until 1971. Pascal had to solve much harder technical problems to work with this division of the livre into 240 than he would have had if the division had been 100. Pascal attempted to put the machine into production for his own profit. This was not a successful venture, but it did result in a large number of units surviving to the present day. They are all slightly different in that they have different numbers of of digits in the accumulator or have slight differences in the internal mechanisms. None of the surviving models functions very well, and it is doubtful if they functioned perfectly even in Pascal’s day. The mechanism, although ingenious, is rather delicate and prone to giving erroneous results when not treated with the utmost care. Some of them will, for example, generate extra carries in certain digits of the accumulator when they are bumped or knocked even slightly. Fig 1.05 1.05: Pascal’s adding and subtraction machine 1.4.5 Leibniz’s multiplication and division machines In 1673 German mathematician and philosopher Gottfried Wilhelm Leibniz made a drawing of his calculating machine mechanism. Using a stepped drum, the Leibniz Stepped Reckoner, Reckoner BMG101: Introduction to Computers Page 24 mechanized multiplication as well as addition by performing repetitive additions. The stepped-drum gear, or Leibniz wheel, was the only workable solution to certain calculating machine problems until about 1875. The technology remained in use through the early 1970s in the Curta hand-held calculator. Leibniz first published a brief illustrated description of his machine in "Brevis descriptio machinae arithmeticae, cum figura... ," Miscellanea Berolensia ad incrementum scientiarum (1710) 317-19, figure 73. The lower portion of the frontispiece of the journal volume also shows a tiny model of Leibniz's calculator. Because Leibniz had only a wooden model and two working metal examples of the machine made, one of which was lost, his invention of the stepped reckoner was primarily known through the 1710 paper and other publications. Nevertheless, the machine became well-enough known to have great influence. Leibniz conceived the idea of a calculating machine in the early 1670s with the aim of improving upon Blaise Pascal's calculator, the Pascaline. He concentrated on expanding Pascal's mechanism so it could multiply and divide. The first recorded indirect reference is in a letter from the French mathematician Pierre de Carcavi (Carcavy) dated June 20, 1671 in which Pascal's machine is referred to as "la machine du temps passé." Leibniz demonstrated a wooden model of his calculator at the Royal Society of London on February 1, 1673, though the machine could not yet perform multiplication and division automatically. In a letter of March 26, 1673 to Johann Friedrich, where he mentioned the presentation in London, Leibniz described the purpose of the "arithmetic machine" as making calculations "leicht, geschwind, gewiß" [sic], i.e. easy, fast, and reliable. Leibniz also added that theoretically the numbers calculated might be as large as desired, if the size of the machine was adjusted; quote: "eine zahl von einer ganzen Reihe Ziphern, sie sey so lang sie wolle (nach proportion der größe der Maschine)" ("a number consisting of a series of figures, as long as it may be in proportion to the size of the machine"). Fig 1.06: Stepped Reckoner (Wikipedia) The step reckoner (or stepped reckoner) was a digital mechanical calculator invented by the German mathematician Gottfried Wilhelm Leibniz around 1672 and completed in 1694. The name comes from the translation of the German term for its operating mechanism, Staffelwalze, meaning 'stepped drum'. It was the first calculator that could perform all four arithmetic operations. Its intricate precision gearwork, however, was somewhat beyond the fabrication technology of BMG101: Introduction to Computers Page 25 the time; mechanical problems, in addition to a design flaw in the carry mechanism, prevented the machines from working reliably. Two prototypes were built; today only one survives in the National Library of Lower Saxony (Niedersächsische Landesbibliothek) in Hanover, Germany. Several later replicas are on display, such as the one at the Deutsches Museum, Munich. Despite the mechanical flaws of the stepped reckoner, it suggested possibilities to future calculator builders. The operating mechanism, invented by Leibniz, called the stepped cylinder or Leibniz wheel, was used in many calculating machines for 200 years, and into the 1970s with the Curta hand calculator. 1.4.6 Babbage’s analytical engine The Analytical Engine was a proposed mechanical general-purpose computer designed by English mathematician and computer pioneer Charles Babbage. It was first described in 1837 as the successor to Babbage's difference engine, a design for a mechanical computer. The Analytical Engine incorporated an arithmetic logic unit, control flow in the form of conditional branching and loops, and integrated memory, making it the first design for a general-purpose computer that could be described in modern terms as Turing-complete. In other words, the logical structure of the Analytical Engine was essentially the same as that which has dominated computer design in the electronic era. Babbage was never able to complete construction of any of his machines due to conflicts with his chief engineer and inadequate funding. It was not until the 1940s that the first general-purpose computers were actually built, more than a century after Babbage had proposed the pioneering Analytical Engine in 1837. Fig 1.06: Trial model of a part of the Analytical Engine, built by Babbage, as displayed at the Science Museum (London) BMG101: Introduction to Computers Page 26 The Analytical Engine was to be a general-purpose, fully program-controlled, automatic mechanical digital computer. It would be able to perform any calculation set before it. There is no evidence that anyone before Babbage had ever conceived of such a device, let alone attempted to build one. The machine was designed to consist of four components: the mill, the store, the reader, and the printer. These components are the essential components of every computer today. The mill was the calculating unit, analogous to the central processing unit (CPU) in a modern computer; the store was where data were held prior to processing, exactly analogous to memory and storage in today’s computers; and the reader and printer were the input and output devices. As with the Difference Engine, the project was far more complex than anything theretofore built. The store was to be large enough to hold 1,000 50-digit numbers; this was larger than the storage capacity of any computer built before 1960. The machine was to be steam-driven and run by one attendant. The printing capability was also ambitious, as it had been for the Difference Engine: Babbage wanted to automate the process as much as possible, right up to producing printed tables of numbers. The reader was another new feature of the Analytical Engine. Data (numbers) were to be entered on punched cards, using the card-reading technology of the Jacquard loom. Instructions were also to be entered on cards, another idea taken directly from Joseph-Marie Jacquard. The use of instruction cards would make it a programmable device and far more flexible than any machine then in existence. Another element of programmability was to be its ability to execute instructions in other than sequential order. It was to have a kind of decision-making ability in its conditional control transfer, also known as conditional branching, whereby it would be able to jump to a different instruction depending on the value of some data. This extremely powerful feature was missing in many of the early computers of the 20th century. By most definitions, the Analytical Engine was a real computer as understood today—or would have been, had Babbage not run into implementation problems again. Actually building his ambitious design was judged infeasible given the current technology, and Babbage’s failure to generate the promised mathematical tables with his Difference Engine had dampened enthusiasm for further government funding. Indeed, it was apparent to the British government that Babbage was more interested in innovation than in constructing tables. All the same, Babbage’s Analytical Engine was something new under the sun. Its most revolutionary feature was the ability to change its operation by changing the instructions on punched cards. Until this breakthrough, all the mechanical aids to calculation were merely calculators or, like the Difference Engine, glorified calculators. The Analytical Engine, although not actually completed, was the first machine that deserved to be called a computer. 1.4.7 Mechanical calculator In 1775 Earl Stanhope, in England, made two machines. Some say he copied Pascal, but he didn't. His are very different. One of them, if it had worked accurately, would have been the prototype of that class of machine known as the Odhner type. Odhner lived in Russia. Some say he was a Pole, but I believe he was a Scandinavian. He made a successful machine about 1876. There is a great family of machines made in Europe at present, known as the Odhner type ; probably twenty factories making such machines. The Brunsviga is one of them. Odhner manufactures them himself in Russia, but he is not so successful commercially as are the French and German manufacturers of that type of machine. BMG101: Introduction to Computers Page 27 But a hundred years earlier—1775—Lord Stanhope had in his machine the heart of the Odhner machine. Each kind of machine—I do not care whether it be an automobile or a calculating machine—has some fundamental feature, some heart, some key to it, which represents the invention, which once thought of and produced successfully, the rest is easy. That feature of the Odhner machine is found in the machine of Earl Stanhope for the first time. But it is not accurate and never was. It is very fragile. They wouldn't let me operate it in the museum where it is preserved in London, but I examined it very closely. No doubt it could be operated if handled very delicately and would get results. Fig 1.07: Charles Stanhope (Source: Wikipedia) Another machine made by Earl Stanhope about the year 1777, contained the heart of what is known as the Thomas type of machine. That machine contained a series of toothed wheels, having wide faces bearing ten very long teeth ; the first one, reaching clear across the face, representing 9, the next tooth being one-ninth shorter, the next one-eighth shorter, and so on. If you want to add 9, you shove the toothed wheel along so that nine teeth will engage; if 8, you shove it along so that eight will engage. That is in the second Stanhope machine, and it is the general principle of the Thomas machine. In the Odhner type they get the variable number of engaging teeth by having a wheel with movable teeth in it so they can slide in and out. As they turn a lever more or fewer teeth slide out. 1.5 ELECTRICAL CALCULATOR Electronic calculating for the office had to wait on the miniaturisation of valves and the development of solid state transistors. ANITA: First desktop all electronic calculator. BMG101: Introduction to Computers Page 28 The first step was seen in 1961 with the arrival of ANITA (A New Inspiration To Arithmetic/Accounting). This was the world’s first all-electronic desktop calculator and it was developed in Britain by Control Systems Ltd., marketed under its Bell Punch and Sumlock brands. ANITA used the same push button key layout as the company’s mechanical comptometers, but these were the only moving parts. All the rest was done electronically, using a mix of vacuum and cold cathode ‘Dekatron’ counting tubes. The illuminated 12-place display was provided by ‘Nixie’ glow discharge tubes. From 1962, two models were marketed; ANITA Mk. 7 for continental Europe and the Mk. 8 for Britain and the rest of the world, with the latter soon becoming the only model. Fig 1.08 ANITA Mark VIII (Source: Wikipedia) Nevertheless, as the only electronic desktop calculator available, tens of thousands of ANITAs were sold worldwide up to 1964, when three new transistorised competitors appeared; the American Friden 130 series, the Italian IME 84, and the Sharp Compet CS10A from Japan. 1.5.1 Modern Electronic Calculator An electronic calculator is a small, portable electronic device used to perform calculations, BMG101: Introduction to Computers Page 29 ranging from basic arithmetic to complex mathematics. The first solid state electronic calculator was created in the 1960s, building on the extensive history of tools such as the abacus (developed around 2000 BC), and the mechanical calculator (developed in the 17th century AD). It was developed in parallel with the analog computers of the day. The pocket sized devices became available in the 1970s, especially after the first microprocessor, the Intel 4004, developed by Intel for the Japanese calculator company Busicom. They later became used commonly within the petroleum industry (oil and gas). Modern electronic calculators vary: from cheap, give-away, credit-card-sized models to sturdy desktop models with built-in printers. They became popular in the mid-1970s (as integrated circuits made their size and cost small). By the end of that decade, calculator prices had reduced to a point where a basic calculator was affordable to most and they became common in schools. Fig 1.09: An electronic pocket calculator with a liquid-crystal display (LCD) seven-segment display, that can perform arithmetic operations. BMG101: Introduction to Computers Page 30 Computer operating systems as far back as early Unix have included interactive calculator programs such as dc and hoc, and calculator functions are included in almost all personal digital assistant (PDA) type devices (save a few dedicated address book and dictionary devices). In addition to general purpose calculators, there are those designed for specific markets. For example, there are scientific calculators which include trigonometric and statistical calculations. Some calculators even have the ability to do computer algebra. Graphing calculators can be used to graph functions defined on the real line, or higher-dimensional Euclidean space. As of 2016, basic calculators cost little, but the scientific and graphing models tend to cost more. In 1986, calculators still represented an estimated 41% of the world's general-purpose hardware capacity to compute information. By 2007, this diminished to less than 0.05%. Internal Working In general, a basic electronic calculator consists of the following components: Power source (mains electricity, battery and/or solar cell) Keypad (input device) – consists of keys used to input numbers and function commands (addition, multiplication, square-root, etc.) Display panel (output device) – displays input numbers, commands and results. Liquid- crystal displays (LCDs), vacuum fluorescent displays (VFDs), and light-emitting diode (LED) displays use seven segments to represent each digit in a basic calculator. Advanced calculators may use dot matrix displays. A printing calculator, in addition to a display panel, has a printing unit that prints results in ink onto a roll of paper, using a printing mechanism. Processor chip (microprocessor or central processing unit). Example A basic explanation as to how calculations are performed in a simple 4-function calculator: To perform the calculation 25 + 9, one presses keys in the following sequence on most calculators: 2 5 + 9 =. When 2 5 is entered, it is picked up by the scanning unit; the number 25 is encoded and sent to the X register; Next, when the + key is pressed, the "addition" instruction is also encoded and sent to the flag or status register; The second number 9 is encoded and sent to the X register. This "pushes" (shifts) the first number out into the Y register; When the = key is pressed, a "message" (signal) from the flag or status register tells the permanent or non-volatile memory that the operation to be done is "addition"; The numbers in the X and Y registers are then loaded into the ALU and the calculation is carried out following instructions from the permanent or non-volatile memory; The answer, 34 is sent (shifted) back to the X register. From there, it is converted by the binary decoder unit into a decimal number (usually binary-coded decimal), and then shown on the display panel. BMG101: Introduction to Computers Page 31 Other functions are usually performed using repeated additions or subtractions. CHECK YOUR PROGRESS Describe an abacus. What are the types of computing machines Elaborate on Napier’s bones. How was Napier’s bones used for calculations. What is a slide rule? How is it used? Describe Pascal’s adding and subtracting machines. Elaborate on the importance or Leibnitz Multiplication and Division Machines. Discuss the importance of Babbage’s Analytical Engine. Describe the contribution of Earl Charles Stanhope in the field of computing machines. Explain the importance of ANITA in the history of computing. Describe the internal working of an electronic calculator. 1.6 COMPUTER GENERATIONS The history of computer development is often in reference to the different generations of computing devices. Each of the five generations of computers is characterized by a major technological development that fundamentally changed the way computers operate. Most major developments resulted in increasingly smaller, cheaper and more powerful and efficient computing devices. 1.6.1 First generation computers (1939-1954): Vacuum Tube The first electronic computer, the ABC (Atanasoff Berry Computer) was designed in 1937 to solve only systems of linear equation. The ENIAC (electronic numerical integrator and computer) was built in 1945 for calculations and because people demanded for the solution to war. It was the world’s first general-purpose electronic digital computer. It used thousands of vacuum tubes, which took up a lot of space and since the tubes failed frequently it was never useful. Engineers solved this problem by suggesting never turning it off = lots of power. BMG101: Introduction to Computers Page 32 UNIVAC (Universal Automatic Computer) was advancement of the ENIAC. It was the first commercial computer in 1951. This computer weighed 29,000 pounds and used 5200 vacuum tubes, you could imagine how much room and how big this computer is. The UNIVAC went through many redesigns, which enhanced the memory, speed, and multiprocessor increased, and decreasing the weight and space. Fig 1.10: Control panel of UNIVAC 1213 (Source: Wikipedia) The Computer in the first generation was based upon the creation of the vacuum tube and magnetic drums for memory. It gave off a lot of heat and even with a gigantic air conditioner it would overheat. Also think of the amount of space it took up.The Vacuum tube amplifies weak signals making it stronger and can start/stop the flow of electricity. The vacuum tube was what drove the expansion and commercialization of radio broadcasting, television, analog and digital computers etc. Uses machine language the lo

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