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  • Fundamentals of Cumputing Sem1 2009/2010 Ronald Golooba
  • Fundamentals of Cumputing Sem1 2009/2010 Ronald Golooba Fundamentals of Computers- Bugema University 2009/2010
  • Fundamentals of Cumputing Sem1 2009/2010 Ronald Golooba
  • Fundamentals of Cumputing Sem1 2009/2010 Ronald Golooba
  • Fundamentals of Cumputing Sem1 2009/2010 Ronald Golooba
  • Fundamentals of Cumputing Sem1 2009/2010 Ronald Golooba
  • Fundamentals of Cumputing Sem1 2009/2010 Ronald Golooba
  • Fundamentals of Cumputing Sem1 2009/2010 Ronald Golooba
  • © 2002 McGraw-Hill Companies Information systems depend on software resources to help end users use computer hardware to transform data into information products. Software handles the input, processing, output, storage, and control activities of information systems. Computer software is typically classified into two major types of programs: Systems Software . These are programs that manage and support the resources and operations of a computer system. A. System Management Programs . These programs help run the hardware and communicate critical information throughout the IS. Examples are operating systems, operating environments (such as GUI interfaces), database management systems, and telecommunications monitors. B. System Development Programs . These programs are used to build new application programs or specific information systems applications. Examples include programming language translators, programming environments, and CASE packages. Applications Software . These are programs that direct the performance of a particular use, or application, of computers to develop specific information products by end users. A. General-Purpose Application Programs . These programs allow end users to create a great many different information products within a general knowledge category. Examples include word processing, spreadsheets, database managers, graphics, and integrated packages. B. Application-Specific Programs . These programs are dedicated to very specific functions within a knowledge area. Examples include programs for accounting, generating marketing plans, or handling financing. Teaching Tips This slide corresponds to Figure 4.2 on p. 108 and relates to the material on p. 109.
  • Fundamentals of Cumputing Sem1 2009/2010 Ronald Golooba
  • Fundamentals of Cumputing Sem1 2009/2010 Ronald Golooba
  • Computer viruses are most easily spread by attachments in e-mail messages or by instant messaging messages. Therefore, you must never open an e-mail attachment unless you know who sent the message or unless you are expecting the e-mail attachment. Computer viruses can be disguised as attachments of funny images, greeting cards, or audio and video files. Computer viruses also spread by using downloads on the Internet. Computer viruses can be hidden in pirated software or in other files or programs that you may download. Fundamentals of Cumputing Sem1 2009/2010 Ronald Golooba
  • Fundamentals of Cumputing Sem1 2009/2010 Ronald Golooba
  • Fundamentals of Cumputing Sem1 2009/2010 Ronald Golooba
  • Fundamentals of Cumputing Sem1 2009/2010 Ronald Golooba
  • Development stage is critical. For example, learning behavior of humans is heavily influenced by their development period (and is the reason why money and effort is probably more effective in early stages of development).  In much the same way, the success or failure of an information systems and the amount of maintenance required is dependent on the events during development.
  • Transcript

    • 1. FUNDAMENTALS OF COMPUTING By JOEL AMENYA K. Tel:0724269229 Email: joamesh@gmail.com, joamesh@hotmail.com for assignemnt
    • 2. Introduction O What is a computer? O It is an electronic programmable machine that accepts data as input process it and give output in form information. O It is composed of two major components: O Hardware and O software. 06/27/13 Fundamentals of Computing by Joel Amenya 2
    • 3. Common Computer terms O Hardware: the physical tangible parts or components of a computer system O Software: these are sets of instruction (programs) used to direct the operation of a computer. such as word process, manage databases, play games, etc O Softcopy: This is unprinted information/data or instructions in the computer. O Hardcopy: means printed output, or information that has been printed on paper stationary. 06/27/13Fundamentals of Computing by Joel Amenya 3
    • 4. Common Computer terms cont’d O Peripheral: electronic equipment connected by cable to the computer. They are used to increase the functionality of the computer. E.g. printer, scanner O Data: Raw facts of information that have not been processed thus are not meaningful to the user. O Information: This processed data that is meaningful to the user. 06/27/13Fundamentals of Computing by Joel Amenya 4
    • 5. Computer evolution/History O Computer History and Generations O Abacus computers - These were the first computers cable of only doing addition and subtraction O Pascaline - This was a mathematical calculator which performs addition and subtraction O G.W Leinbiz - Stepped up performance and uses punch card for storage of information, they had got additional function besides addition and subtraction, and also performs square root functionality O Charles Babbage - Uses engine and could compute data and store data and information. They were analytical machine which works as the present computers 06/27/13Fundamentals of Computing by Joel Amenya 5
    • 6. Computer Generations First Generation Computers O Characteristics of 1st generation Computers 1946 - 1959 O These computers used vacuum tube for data processing and storage. O They had a memory size of 20bytes speed of 5mbps (very small). O They produced a lot of heat. O These computers were unreliable and could not work fast with a lot of data. O They uses punch card for data storage. O The programmer were machine dependent. O First generation consume a lot of power. 06/27/13Fundamentals of Computing by Joel Amenya 6
    • 7. Second Generation of Computer. 1959-1964 O Were capable of translating, process and store data O Had got memory size of 32bytes speed of 10mbps O Were reliable compared to first generation computers O Produced less heat compared to first generation computers O They uses punch card for data storage O Consumed less energy compared to first generation computers 06/27/13Fundamentals of Computing by Joel Amenya 7
    • 8. Third generation Computers 1965 - 1975 O They used integrated circuit(i.c.) to store data O The integrated circuit consisted of many transistors O Uses storage disk for data storage e.g. magnetic disks, tapes O Third generation computers were more reliable compared to other previous generations O They produced less heat 06/27/13Fundamentals of Computing by Joel Amenya 8
    • 9. Fourth Generation Computers O 1975 to present O These are computers in use today; they use sophisticated micro-electronic devices O These computers uses micro processors to process data O The micro processors are single chip which perform computer operation O Programs are machine independent O Were more reliable 06/27/13Fundamentals of Computing by Joel Amenya 9
    • 10. Fifth generation computers 1990 to present. O These are predictions that by early 21st century computers will have developed that will be able to converse with people, human communication. With the fifth generation there will be artificial intelligent computers. 06/27/13Fundamentals of Computing by Joel Amenya 10
    • 11. Categories of Computers O Computer systems may be classified according to the data they are designed to process Analog Computers: Analog Computers O The analog computers do not directly interact with numbers, but rather deal with variables measured along a continuous scale, like the temperature of a room. O It uses continuous variables for mathematical operations and utilizes mechanical or electrical energy. O Analog computers may be accurate to within 0.1% of the correct value. O Analog computer can perform several mathematical operations simultaneously. 06/27/13Fundamentals of Computing by Joel Amenya 11
    • 12. Digital Computers O  A digital computer operates on discrete data. That is Data expressed in 0’s and 1’s O It works basically by directly counting numbers that represent numerals, letters or other functional symbols. O Digital computers can be further divided into special purpose and general purpose digital computers. O  A special purpose digital computer is one which has been designed to perform one specific task. The set of instructions required for that task is permanently stored in the computer's memory. O What this type of computer lacks in variety, it makes up in speed and efficiency. 06/27/13Fundamentals of Computing by Joel Amenya 12
    • 13. Digital computers cont. O  A general purpose computer is one which can store different programs and is also re-programmable. O The only limitation to the versatility of this type of computer is the extent of imagination of the human mind. O In fact, these computers can be made to perform a surplus of different and varied functions. 06/27/13Fundamentals of Computing by Joel Amenya 13
    • 14. Hybrid Computers O  A hybrid computing system is one in which desirable characteristics of both the analog and digital computers are integrated. O In an intensive care unit, analog computers may measure the patient's heart rate, temperature, etc. O The measurements may then be converted into numbers and supplied to the digital part of the system which will thereafter regulate the flow of certain medications. 06/27/13Fundamentals of Computing by Joel Amenya 14
    • 15. Classification According to Size and Memory Capacity O The size of a computer often determines its function and processing capacity. O The size of computers varies widely from tiny to huge and is usually dictated by computing requirements. O The largest computers are supercomputers. O They are the most powerful, the most expensive, and the fastest, capable of processing trillions of instructions per second. O Users of these computers are governmental agencies, such as the, National Weather Service, and the National Defense Agency. O Also, they are used in the making of movies, space exploration, and the design of many other machines.06/27/13Fundamentals of Computing by Joel Amenya 15
    • 16. Mainframe Computers. O The second largest computers are called mainframes. O Mainframe computers process data at very high rates of speed, measured in the millions of instructions per second. O They are very expensive, costing millions of dollars in some cases. O Mainframes are designed for multiple users and process vast amounts of data quickly. O Banks, insurance companies, manufacturers, mail- order companies, and airlines are typical users. O Mainframes are often ‘servers’-- computers that control the networks of computers. 06/27/13Fundamentals of Computing by Joel Amenya 16
    • 17. Microcomputers O Microcomputers A computer with a microprocessor and its central processing unit is known as a microcomputer. O They do not occupy space as much as mainframes. O When supplemented with a keyboard and a mouse, microcomputers are known as personal computers. O A monitor, a keyboard and other similar input output devices, computer memory in the form of RAM and a power supply unit come packaged in a microcomputer. O These computers can fit on desks or tables and serve as the best choices for single-user tasks. 06/27/13Fundamentals of Computing by Joel Amenya 17
    • 18. Minicomputers O A minicomputer system is a small general purpose computer varying in size from a desktop model to a unit the size of a four drawer filing cabinet". O It is quite obvious that there is tremendous amount of similarity between the more powerful micros and the lower end minis. O The same situation exists on the other end where the lower priced mainframes are almost similar to the higher priced minis. 06/27/13Fundamentals of Computing by Joel Amenya 18
    • 19. Notebook Computers O Another classification of computer is the notebook computer. O It can fit into a briefcase and weigh fewer than two pounds, yet it can compete with the microcomputer. O A larger, heavier version is called a laptop computer. O Notebooks generally cost more than microcomputers but can run most of the microcomputer software and are more versatile. O Like other computers, notebook computers are getting faster, lighter, and more functional. 06/27/13Fundamentals of Computing by Joel Amenya 19
    • 20. PDAs O The smallest computer is the handheld computer called a personal digital assistant or a PDA. O PDAs are used to track appointments and shipments as well as names and addresses. O They are called pen-based computers because they utilize a pen-like stylus that accepts hand-written input directly on a touch-sensitive screen. O You have probably noticed delivery employees using these. 06/27/13Fundamentals of Computing by Joel Amenya 20
    • 21. Factors to consider when buy a computer O Cost O Processing speed O Storage capacity O Memory size O Software and hardware compatibility O Maintenance support from the manufacturer O User needs 06/27/13Fundamentals of Computing by Joel Amenya 21
    • 22. Characteristics of a computer O Speed: Computers work at very high speed and are much faster than humans. A second is very large time period time for computer. A computer can perform billions of calculations in a second. The time used by a computer to perform an operation is called the processing speed. Computer speed is measured in Mega Hertz (MHz). 06/27/13Fundamentals of Computing by Joel Amenya 22
    • 23. Characteristics of a computer Cont’dO Accuracy Computer provides a high degree of accuracy. For example, the computer can accurately give the result of division of any two numbers up to 10 decimal places. O Diligence. When used for a longer period of time, the computer does not get tired or fatigued. It can perform long and complex calculations with the same speed and accuracy from the start till the end. O Versatility Computer is versatile in nature. It can perform different types of tasks with the same ease. At one moment you can use the computer to prepare a letter document and in the next moment you may play music or print a document. 06/27/13Fundamentals of Computing by Joel Amenya 23
    • 24. Characteristics of a computer Cont’dO Storage Capability. Large volumes of data and information can be stored in the computer and also retrieved whenever required. Secondary storage devices like floppy disk and compact disk can store a large amount of data permanently. O Reliable. Most errors are caused by humans, not computers. Computers are capable of storing enormous amounts of data that must be located and retrieved very quickly. The capability to store and retrieve volumes of data is at the core of the Information Age. 06/27/13Fundamentals of Computing by Joel Amenya 24
    • 25. Assignment O Find advantage and disadvantages of using computers. 06/27/13Fundamentals of Computing by Joel Amenya 25
    • 26. Chapter Two O Computer Components O Hardware, O Software, O Live ware or orgware. 06/27/13Fundamentals of Computing by Joel Amenya 26
    • 27. General computer concepts O What is the meaning of the terms hardware, software, Information Technology (IT)? O Hardware • The term hardware refers to the physical components of a computer such as the system unit, mouse, keyboard, monitor etc. 06/27/13Fundamentals of Computing by Joel Amenya 27
    • 28. Software O Software • The software is the collection of instructions which makes the computer work. O For instance, when you type in words via the keyboard, the software is responsible for displaying the correct letters, in the correct place on the creen. O Software is held either on your computer’s hard disk, CD-ROM, DVD or on a diskette (floppy disk) and is loaded (i.e. copied) from the disk into the computers RAM (Random Access Memory), as and when required. 06/27/13Fundamentals of Computing by Joel Amenya 28
    • 29. Computer Diag’ 06/27/13Fundamentals of Computing by Joel Amenya 29
    • 30. Information Technology (IT) • This is a general term which relates to the use of computers as an aid to creating and maintaining data, i.e. information. O IT is related to all aspects of managing and processing information, especially within a large organisation. O Computers are critical to managing information, and computer departments within large organisations are often called IT departments. or IS departments (Information Services) or MIS departments (Management Information Services). 06/27/13Fundamentals of Computing by Joel Amenya 30
    • 31. Main parts of a computer Hardware - Central Processing Unit (CPU) O In terms of computing power, the CPU is the most important element of a computer system. O “It is the brain of the computer.” O CPU or processor or Microprocessor is an electronic circuit that can execute a sequence of stored instructions called programs. O CPU controls all internal and external devices, performs arithmetic and logic operations. 06/27/13Fundamentals of Computing by Joel Amenya 31
    • 32. Hardware Classification O Hardware can also be referred to as Devices. These are the physical parts of a computer that a user can see and touch. They include O Input Devices. O Output Devices. O Storage Devices. O Processing Devices. O Network Devices. 06/27/13Fundamentals of Computing by Joel Amenya 32
    • 33. 06/27/13Fundamentals of Computing by Joel Amenya 33 Input O Input is any data or instructions entered into the computer’s memory
    • 34. 06/27/13Fundamentals of Computing by Joel Amenya 34 Input Devices: Giving Commands O Input devices are types of hardware that enable you to get programs, data, commands, and responses into the computer’s memory Keyboard Mouse Stylus
    • 35. 06/27/13Fundamentals of Computing by Joel Amenya 35 Keyboard O The keyboard allows the computer user to enter words, numbers, punctuation, symbols, and special function commands into the computer’s memory
    • 36. 06/27/13Fundamentals of Computing by Joel Amenya 36 Types of Keyboard O Multimedia keyboard -for playing games O Enhanced or Extended keyboard – Typically 101 keys laid out in the QWERTY fashion; connected to the computer by a serial cable O Cordless keyboard – Uses infrared or radio wave signals O Ergonomic keyboard – Designed to help prevent Cumulative Trauma Disorder (CTD) or damage to nerve tissues in the wrist and hand due to repeated motion Enhanced / Extended Keyboard Ergonomic Keyboard
    • 37. Types Of keyboard keys O Function keys as shortcuts for performing certain functions such as saving files or printing data. Function keys usually are lined along the top of the keyboard labeled F1 through F12, although some keyboards have fewer and others may have more. 06/27/13Fundamentals of Computing by Joel Amenya 37
    • 38. Types Of keyboard keys cont’d O Modifiers/ Special pc keys. are special keys that modify the normal action of another key, when the two are pressed in combination. For example, <Alt> + <F4> in Microsoft Windows will close the program in an active window. O The most widely-used modifier keys include the Control key, Shift key and the Alt key. The Alt key is used to access additional symbols for keys that have three symbols printed on them. 06/27/13Fundamentals of Computing by Joel Amenya 38
    • 39. Types Of keyboard keys cont’d O System commands. This are keys used to issue some system commands to the computer. They are keys like Break key/Pause, he SysRq / Print screen key the Escape key. O The Print screen command used to capture the entire screen and send it to the printer, but in the present it usually puts a screenshot in the clipboard. O The Escape key (often abbreviated Esc) is used to initiate an escape sequence. Its used most often to mean Stop. 06/27/13Fundamentals of Computing by Joel Amenya 39
    • 40. Types Of keyboard keys cont’d O Numeric keys: The number keys are used to type numbers. 0,1,2,3,4,5,6,7,8,9. These are called as number keys O Alphanumeric keys- used to enter both numeric and alphabetical data to the computer. 06/27/13Fundamentals of Computing by Joel Amenya 40
    • 41. Types Of keyboard keys cont’d O Navigation and typing modes O Navigation keys include a variety of keys which move the cursor to different positions on the screen. Arrow keys are programmed to move the cursor in a specified direction; page scroll keys, such as the 'Page Up and Page Down keys', scroll the page up and down. The Home key is used to return the cursor to the beginning of the line where the cursor is located; the End key puts the cursor at the end of the line. The Tab key advances the cursor to the next tab stop. 06/27/13Fundamentals of Computing by Joel Amenya 41
    • 42. Types Of keyboard keys cont’d O Miscellaneous O Not all, computer keyboards have a numeric keypad to the right of the alphabetic keyboard which contains numbers, basic mathematical symbols (e.g., addition, subtraction, etc.), and a few function keys. On Japanese/Korean keyboards, there may be Language input keys. Some keyboards have power management keys (e.g., Power key, Sleep key and Wake key); Internet keys to access a web browser or E-mail; and/or multimedia keys, such as volume controls or keys that can be programmed by the user to launch a specified software or command like launching a game or minimize all windows. 06/27/13Fundamentals of Computing by Joel Amenya 42
    • 43. 06/27/13Fundamentals of Computing by Joel Amenya 43 Mouse O The mouse is the most widely used pointing device O A mouse is palm sized O As the mouse is moved, its movements are mirrored by the on-screen pointer O Mouse pad – clean, flat surface for mouse movement
    • 44. 06/27/13Fundamentals of Computing by Joel Amenya 44 Types of Mouse O Wheel mouse – Contains a rotating wheel used to scroll vertically within a text document; connects to PS/2 port or USB port O Cordless mouse – Uses infrared signals to connect to the computer’s IrDA port; it must be within sight of the receiving port Wheel Mouse Cordless Mouse
    • 45. 06/27/13Fundamentals of Computing by Joel Amenya 45 PS/2 Port The color-coded PS/2 connection ports:  Purple for keyboard  Green for mouse
    • 46. 06/27/13Fundamentals of Computing by Joel Amenya 46 How a Mouse Works Mouse operaton O Mouse buttons enable the user to initiate actions O Clicking (left-, right-, or double-clicking) allows the user to select an item on the screen or open a program or dialog box O Click and drag – Holding down the left mouse button and moving the mouse enables the user to move objects on the screen O Scrolling- Operation achieved by the use of the mouse elevator.
    • 47. 06/27/13Fundamentals of Computing by Joel Amenya 47 Other Types of Pointing Devices Joystick Touch Pad Touch ScreenTrackball Pointing Stick Pen
    • 48. 06/27/13Fundamentals of Computing by Joel Amenya 48 Image Processing Systems: Scanners O Image processing systems are used in business, industry, and science to input data without manually keying it in Scanners
    • 49. 06/27/13Fundamentals of Computing by Joel Amenya 49 MICR Image Processing Systems: Scanners Magnetic-ink character recognition (MICR) A computer can read numbers and letters printed with ink containing magnetic material. MICR is used by banks to process cheques. The account details at the bottom of the cheque can be accurately read in this manner since MICR is not affected by dirt.  Optical Mark Reader (OMR) – A scanning device that senses the magnetized marks from #2 pencils.
    • 50. 06/27/13Fundamentals of Computing by Joel Amenya 50 Alternative Input Devices Barcode reader Microphone – Speech recognition
    • 51. 06/27/13Fundamentals of Computing by Joel Amenya 51 Digital Camera Digital Video Video-conferencing Web Cam Alternative Input Devices
    • 52. 06/27/13Fundamentals of Computing by Joel Amenya 52 Speech Recognition - Microphone O Speech recognition is a type of input in which the computer recognizes words spoken into a microphone O Special software and a microphone are required O A microphone – an input device that converts sound input into electrical signals O Latest technology uses continuous speech recognition where the user does not have to pause between words
    • 53. 06/27/13Fundamentals of Computing by Joel Amenya 53 Digital Cameras O The image’s light falls on a charge-coupled device (CCD) which transforms the light’s patterns into pixels O Images are stored in the camera using flash memory. The most popular types are CompactFlash and SmartMedia. O Photo-editing programs enable the user to edit the images O Good pictures can be taken using point-and- shoot cameras O Single-lens reflex (SLR) digital cameras are expensive and used by professional photographers
    • 54. 06/27/13Fundamentals of Computing by Joel Amenya 54 Digital Video O A video capture board transforms analog video into digital video O Codes or compression/decompression standards are used to compress digital video files O A frame rate of 24 frames per second (fps) is needed to produce a continuous smooth action
    • 55. 06/27/13Fundamentals of Computing by Joel Amenya 55 Video-conferencing O Videoconferencing uses digital video technology to simulate face-to-face meetings O Whiteboards, which are a part of the screen, can be used to write or draw
    • 56. 06/27/13Fundamentals of Computing by Joel Amenya 56 Web Cam O A Web cam provides low- resolution video- conferencing for Internet users O The images are small and jerky
    • 57. 06/27/13Fundamentals of Computing by Joel Amenya 57 Output Devices O Output devices are peripheral devices that enable users to view or hear the computer’s processed data O Visual output – Text, graphics, and video O Audio output – Sounds, music, and synthesized speech
    • 58. 06/27/13Fundamentals of Computing by Joel Amenya 58 Visual Display System O A visual display system is composed of two parts: O Video adapter – Responsible for video quality O Monitor – Displays the video adapter’s output 58
    • 59. 06/27/13Fundamentals of Computing by Joel Amenya 59 Video Adapter O A video adapter is also called display adapter, video card, or graphics card O It plugs into an expansion slot on the motherboard O It contains memory called video RAM (VRAM) O It is designed to work with digital or analog monitors O It converts digital signals to analog O It determines a monitor’s maximum resolution (VGA/Super VGA) O It determines a monitor’s refresh rate O 3D graphics adapter – Enables 3-dimensional images O Multi-display video adapter – Permits a connection of two monitors at a time
    • 60. 06/27/13Fundamentals of Computing by Joel Amenya 60 Monitors O A monitor is a peripheral device which displays computer output on a screen. O Screen output is referred to as soft copy. O Types of monitors: O Cathode-ray tube (CRT) O Liquid Crystal Display (LCD or flat-panel) CRT LCD
    • 61. 06/27/13Fundamentals of Computing by Joel Amenya 61 Cathode-ray tube (CRT) O Resembles televisions O Uses picture tube technology O Less expensive than a LCD monitor O Takes up more desk space and uses more energy than LCD monitors
    • 62. 06/27/13Fundamentals of Computing by Joel Amenya 62 Liquid Crystal Display (LCD) O Cells sandwiched between two transparent layers form images O Used for notebook computers, PDAs, cellular phones, and personal computers O More expensive than a CRT monitor O Takes up less desk space and uses less energy than CRT monitors O Types of LCD monitors: O Passive-matrix LCD O Active-matrix LCD O Gas plasma display O Field emission display
    • 63. 06/27/13Fundamentals of Computing by Joel Amenya 63 Monitor Specifications O Screen size – The diagonal measurement of the screen surface in inches (15, 17, 19, 21) O Resolution – The sharpness of the image determined by the number of horizontal and vertical dots (pixels) that the screen can display (800 x 600, 1024 x 768, 1600 x 1200) O Refresh rate – The speed at which the screen is redrawn (refreshed) and measured in Hertz (Hz) (60Hz, 75Hz)
    • 64. 06/27/13Fundamentals of Computing by Joel Amenya 64 Printers O A printer is a peripheral device that produces a physical copy or hard copy of the computer’s output O Two basic types: O Impact printer O Non-impact printer
    • 65. 06/27/13Fundamentals of Computing by Joel Amenya 65 Impact Printer O An impact printer is a printer that has a print head that contacts the paper to produce a character O It uses ink ribbon O It is noisy, produces Near-letter quality printouts, and is not commonly used today O Dot-matrix – Pins are used to make characters Impact printer Dot-matrix
    • 66. 06/27/13Fundamentals of Computing by Joel Amenya 66 Multifunction Printer O A multifunction printer combines the functions of a non-impact printer, scanner, fax machine, and copier in one unit
    • 67. 06/27/13Fundamentals of Computing by Joel Amenya 67 Non-impact Printer O Inkjet printer, also called a bubble-jet, makes characters by inserting dots of ink onto paper O Letter-quality printouts O Cost of printer is inexpensive but ink is costly Inkjet Laser  The non-impact printer is the most commonly used printer today  It works quietly compared to an impact printer  Laser printer works like a copier  Quality determined by dots per inch (dpi) produced  Color printers available  High initial costs but cheaper to operate per page
    • 68. 06/27/13Fundamentals of Computing by Joel Amenya 68 Plotter O A plotter is a printer that uses a pen that moves over a large revolving sheet of paper O It produces high-quality images O It is used in engineering, drafting, map making, and seism otology
    • 69. Factors to consider before buying a printer O Cost O Volume expected to be printed O Nature of reports to be printed O Range of capability of the selected printer O The interface with which its to connect to the computer. E.g. parallel or USB. 06/27/13Fundamentals of Computing by Joel Amenya 69
    • 70. 06/27/13Fundamentals of Computing by Joel Amenya 70 Audio Output O Audio output is the ability of the computer to output sound O Two components are needed: O Sound card – Plays contents of digitized recordings O Speakers – Attached to sound card O Digital formats include WAV, MPEG, MP3, and MIDI
    • 71. Processing Devices CPU O The program is represented by a series of numbers that are kept in some kind of computer memory. O The CPU processes which is obtained, via the system bus, from the main memory. O Results from the CPU are then sent back to main memory via the system bus. O In addition to computation the CPU controls and co-ordinates the operation of the other major components. O The CPU has two main components, namely: 06/27/13Fundamentals of Computing by Joel Amenya 71
    • 72. Processing Devices 06/27/13Fundamentals of Computing by Joel Amenya 72
    • 73. CPU O The Control Unit -- controls the fetching of instructions from the main memory and the subsequent execution of these instructions. O Among other tasks carried out are the control of input and output devices and the passing of data to the Arithmetic/Logical Unit for computation. 06/27/13Fundamentals of Computing by Joel Amenya 73
    • 74. CPU Component O The Arithmetic/Logical Unit (ALU) -- carries out arithmetic operations on integer (whole number) and real (with a decimal point) operands. O It can also perform simple logical tests for equality and greater than and less than between operands. O It is worth noting here that the only operations that the CPU can carry out are simple arithmetic operations, comparisons between the result of a calculation and other values, and the selection of the next instruction for processing 06/27/13Fundamentals of Computing by Joel Amenya 74
    • 75. Components of a CPU O Registers are temporary storage area inside a CPU O It is a high-speed memory which holds only data for immediate processing and results of this processing 06/27/13Fundamentals of Computing by Joel Amenya 75
    • 76. CPU manufacturersO There are basically two best known makers of CPUs for consumer computers that is AMD and Intel. O AMD's current line of processors includes Athlon, Phenom, Sempron and Turion processors O Intel's current line of processors includes: the Celeron, Pentium, Core 2, Centrino and Centrino 2 processors. 06/27/13Fundamentals of Computing by Joel Amenya 76
    • 77. CPU manufacturers O Today, Intel is the best-known manufacturer of computer CPUs. O Most CPUs conform to the von Neumann architecture, which says that the CPU must fetch, decode, execute, and write back the data in a fairly rapid succession. 06/27/13Fundamentals of Computing by Joel Amenya 77
    • 78. MEMORY and STORAGE What is Storage Device? O A storage device is a hardware device designed to store information. O There are two types of storage devices used in computers; a 'primary storage' device and a 'secondary storage' device.  O Primary Storage is Main Memory O This keeps track of what is currently being processed. It's volatile memory i.e. power off erases all data. O For Main Memory, computers use Random Access Memory (RAM ). This uses memory chips and is the fastest but most expensive type of storage. 06/27/13Fundamentals of Computing by Joel Amenya 78
    • 79. MEMORY STORAGE O Secondary Storage is called Auxiliary Storage O This is what is not currently being processed. This is the stuff "filed away", but ready to be pulled out when needed. It is nonvolatile.  (power off does not erase) Auxiliary Storage is used for: O Input- data & programs. O Output- saving results of processing 06/27/13Fundamentals of Computing by Joel Amenya 79
    • 80. MEMORY STORAGE MAGNETIC DISKS O Of the various types of Auxiliary Storage, the types used most often involve some type of magnetic disk. O These come in various sizes and materials. O This method uses magnetism to store the data on a magnetic surface. O Advantages:- high storage capacity -reliable -gives direct access to data 06/27/13Fundamentals of Computing by Joel Amenya 80
    • 81. TYPES OF MAGNETIC DISKS O Diskette / Floppy Disk O Sizes: Two types 5¼", and 3½" Several other kinds of removable magnetic media are in use, such as the popular Zip disk. O All of these have a much higher capacity than floppy disks. O Some kinds of new computers come without a floppy disk drive at all. O Each type of media requires its own drive. The drives and disks are much more expensive than floppy drives and disks, but then, you are getting much larger capacities. 06/27/13Fundamentals of Computing by Joel Amenya 81
    • 82. TYPES OF MAGNETIC DISKS Hard Disks O These consist of 1 or more metal platters which are sealed inside a case. O The metal is one which is magnetic. O It is usually installed inside the computer's case, though there are removable and cartridge types, also. O  Technically the hard drive is what controls the motion of the hard disks which contain the data. O But most people use "hard disk" and "hard drive" interchangeably. 06/27/13Fundamentals of Computing by Joel Amenya 82
    • 83. TYPES OF MAGNETIC DISKSOPTICAL DISKS O An entirely different method of recording data is used for optical disks it uses light. O To make an optical disk, tiny lasers create peaks and valleys in a plastic layer on a circular disk. O In the device that reads the optical disk these peaks and valleys are read as 1's and 0's by shining another laser on the disk. CD ROM O The most common size of optical disk, which stands for Compact Disk - Read Only Memory. O It looks just like an audio CD. Almost all software is being distributed on CDs now. The price of the drives that read the disks (but can't write one) has dropped low enough that a new system will come with a CD drive. Such drives will also play your audio CDs, if you have a sound card and speakers. O The CDs that contain commercial software are of the Write Once Read Many (WORM) variety. O For changing data we need rewritable disks labeled as CD/RW 06/27/13Fundamentals of Computing by Joel Amenya 83
    • 84. OPTICAL DISKS Advantages of Optical Disc 1.  The optical disk is much sturdier than the other media discussed so far. It is physically harder to break or melt or warp. 2.  It is not sensitive to being touched, though it can get too dirty or scratched to be read. 3. It is entirely unaffected by magnetic fields. 4. Plus you can imprint a pretty label right on the disk! So for software providers, the optical disk is a great way to store the software and data that they want to distribute or sell. Disadvantages 1. The main disadvantage has been cost. But the cost of a CD-RW drive has dropped drastically and quickly. So for commercial use, the read/write drives are quite cost effective. 2.  It is not easy to copy an optical disk. (This is an advantage as far as commercial software providers are concerned!).   06/27/13Fundamentals of Computing by Joel Amenya 84
    • 85. CHAPTER THREE SOFTWARE COMPONENTS O A Computer System is made up of Hardware, Operating System (OS) and user interface. O Computer Software can be divided into: O System programs which manage the operation of the computer itself O Application programs, which solve problems for the users. O The Operating System controls the entire Computers’ resources and provides the base upon which the application programs can be written 06/27/13Fundamentals of Computing by Joel Amenya 85
    • 86. Categories of Computer Software
    • 87. Definition of Operating SystemO An OS is the core software component of your computer program that makes the computing power available to users by controlling the hardware using “Drivers”. O OR- OS is a program that controls the execution of application programs. It masks/covers the details of the hardware to application programs. O Assignment: What Are The Functions Of Operating System? 06/27/13Fundamentals of Computing by Joel Amenya 87
    • 88. What does a driver do? O A driver is a specially written program which understands the operation of the device it interfaces to, such as a printer, video card, sound card or CD ROM drive. O A driver is a program designed to comprehend the functions of a particular device installed on the system. O It translates commands from the operating system or user into commands understood by the component computer part it interfaces with. O It also translates responses from the component computer part back to responses that can be understood by the operating system, application program, or user. 06/27/13Fundamentals of Computing by Joel Amenya 88
    • 89. 06/27/13Fundamentals of Computing by Joel Amenya 89
    • 90. Characteristics of the operating system O Reliable O Protected O Efficient O Predictable O Convenience 06/27/13Fundamentals of Computing by Joel Amenya 90
    • 91. Basic Functions of OSO Memory Allocation and loading of programs. O.S must be responsible for managing all system memory which is currently in use by programs. This ensures that a program does not interfere with memory already in use by another program. Since programs time share, each program must have independent access to memory. O Job scheduling. The job management function of an OS prepares, schedules, controls, and monitors jobs submitted for execution to ensure the most efficient processing. A job is a collection of one or more related programs and their data O Peripheral control. The resource management function of an OS allocates computer resources such as CPU time, main memory, secondary storage, and input and output devices for use. O Error reporting. During execution if an error occurs the OS furnishes the user and tries to minimize effects of the error O Interfacing the user. The OS establishes a standard means of communication between users and their computer systems. It does this by providing a user interface and a standard set of commands that control the hardware. O Logging and account. Keeps record of various operation in the computer 06/27/13Fundamentals of Computing by Joel Amenya 91
    • 92.  Common Operating Systems O Originally the operating system was created by each company that manufactured a processor and motherboard. O Operating system was unique to each manufacturer. O Problem: changing to a new computer meant your software had to be replaced! O There was pressure early on to standardize things so that software could be transferred to the new (and of course better!) computer. This required more standardization in operating systems. O The winner in the PC market was MS-DOS, Microsoft's Disk Operating System, and its twin at IBM, PC-DOS, also written by Microsoft 06/27/13Fundamentals of Computing by Joel Amenya 92
    • 93. Types of Operating Systems O There are several types of operating systems. O Here is an overview on each system: O Windows: Windows is the popular Microsoft brand preferred by most personal users. This system has come a long way from version 1.0 all the way up to the new Vista and soon to be released Windows 7. O Although Windows has made strides in regard to security, it has a reputation for being one of the most vulnerable systems. 06/27/13Fundamentals of Computing by Joel Amenya 93
    • 94. Microsoft suite of operating systems O They include from most recent to the oldest: O Windows XP Professional Edition - A version used by many businesses on workstations. It has the ability to become a member of a corporate domain. O Windows XP Home Edition - A lower cost version of Windows XP which is for home use only and should not be used at a business. O Windows 2000 - A better version of the Windows NT operating system which works well both at home and as a workstation at a business. It includes technologies which allow hardware to be automatically detected and other enhancements over Windows NT. 06/27/13Fundamentals of Computing by Joel Amenya 94
    • 95. Microsoft suite of operating systemsO Windows ME - A upgraded version from windows 98 but it has been historically plagued with programming errors which may be frustrating for home users. O Windows 98 - This was produced in two main versions. The first Windows 98 version was plagued with programming errors but the Windows 98 Second Edition which came out later was much better with many errors resolved. O Windows NT - A version of Windows made specifically for businesses offering better control over workstation capabilities to help network administrators. O Windows 95 - The first version of Windows after the older Windows 3.x versions offering a better interface and better library functions for programs. 06/27/13Fundamentals of Computing by Joel Amenya 95
    • 96. Types of Operating Systems O Unix: is an operating system developed by Bell Labs to handle complex scientific applications. O University networks are likely to use UNIX, as are Internet Service Providers. O It is often used more as a server than a workstation O Unix OS is well known for its stability. O Unix is text based, but X-Windows is a net work based graphical interface for UNIX that some think is even easier to work with than Windows 98. O UNIX is a machine-independent operating system, which means it is not specific to just one type of computer hardware. 06/27/13Fundamentals of Computing by Joel Amenya 96
    • 97. Types of Operating Systems O Linux is an operating system similar to UNIX that is becoming more and more popular. O It is an open-source program created by Linus Torvalds at the University of Finland, starting in 1991. O Open source means that the underlying computer code is freely available to everyone.  O Programmers can work directly with the code and add features. O They can sell their customized version of Linux, as long as the source code is still open to others.  06/27/13Fundamentals of Computing by Joel Amenya 97
    • 98. Types of Operating Systems O Apple Macintosh: is a multitasking operating system that was the first graphical interface to achieve commercial success. O Recent versions of the Macintosh operating system, including the Mac OS X, follow the secure architecture of Unix. O Apple made a major marketing error when they decided to keep their hardware and software under tight control rather than licensing others to produce compatible devices and programs. O Systems developed by Apple are efficient and easy to use, but can only function on Apple branded hardware. 06/27/13Fundamentals of Computing by Joel Amenya 98
    • 99. Operating system updates O Operating systems are updated frequently. O For example, if users find a bug or security hole in an operating system, the company that makes the operating system normally releases an update called a patch or service pack. O This allows you to update your operating system without installing from scratch. O Check the Web site of the company that writes your operating system for the latest information about latest software patches . 06/27/13Fundamentals of Computing by Joel Amenya 99
    • 100. Operating system types O GUI - Short for Graphical User Interface, a GUI Operating System contains graphics and icons and is commonly navigated by using a computer mouse. O Multi-user - A multi-user Operating System allows for multiple users to use the same computer at the same time and/or different times. Below are some examples of multi-user Operating Systems. Linux, Unix, Windows 2000 O Multiprocessing - An Operating System capable of supporting and utilizing more than one computer processor. Below are some examples of multiprocessing Operating Systems. Linux, Unix, Windows 2000 O Multitasking - An Operating system that is capable of allowing multiple software processes to run at the same time. Below are some examples of multitasking Operating Systems. Unix, Windows 2000 O Multithreading - Operating systems that allow different parts of software program to run concurrently. Operating systems that would fall into this category are: Linux, Windows 2000 06/27/13Fundamentals of Computing by Joel Amenya 100
    • 101. 06/27/13Fundamentals of Computing by Joel Amenya 101 UTILITY AND APPLICATION PROGRAMS O Utility software (also known as service program, service routine, tool, or utility routine) is computer software designed to help manage and tune the computer hardware, operating system or application software by performing a single task or a small range of tasks. O Utility Programs perform tasks related to the maintaining of your computer's health - hardware or data. O Some utility software has been integrated into most major operating systems. O Examples, Disk, Defragmenter, Registry cleaners, Antivirus, File Management, Data Recovery, Data Back up, Data Compression, and Memory management.
    • 102. Application Software /Programs O Applications software allows you to perform a particular task or solve a specific problem. Examples of application Software. O Word Processor Provides the tools for entering and revising text, adding graphical elements, formatting and printing documents. O Spreadsheets Provides the tools for working with numbers and allows you to create and edit electronic spreadsheets in managing and analyzing information. 06/27/13Fundamentals of Computing by Joel Amenya 102
    • 103. Examples of application Software O Database Management Provides the tools for management of a collection of interrelated facts. O Data can be stored, updated, manipulated, retrieved, and reported in a variety of ways. O Presentation Graphics Provides the tools for creating graphics that represent data in a visual, easily understood format. O Communication Software Provides the tools for connecting one computer with another to enable sending and receiving information and sharing files and resources. Internet Browser Provides access to the Internet through a service provider by using a graphical interface. 06/27/13Fundamentals of Computing by Joel Amenya 103
    • 104. Relationship Between SoftwareO As important as applications software may be, it is not able to directly communicate with hardware devices. O Another type of software required is the operating systems software. OS software is the set of programs that lies between applications software and the hardware devices. O Think of the cross section of an onion. The inner core of the onion represents the hardware devices, and the applications software represents the outside layer. The middle layer is the OS software. The instructions must be passed from the outer layer through the middle layer before reaching the inner layer. O All computers, regardless of size, require the OS. As soon as your personal computer is turned on, the OS software is loaded into RAM in order to use your computer devices and other software. 06/27/13Fundamentals of Computing by Joel Amenya 104
    • 105. What is a computer virus? O A computer virus is a small software program that spreads from one computer to another computer and that interferes with computer operation. A computer virus may corrupt or delete data on a computer, use an e-mail program to spread the virus to other computers, or even delete everything on the hard disk. 06/27/13Fundamentals of Computing by Joel Amenya 105
    • 106. Symptoms of a computer virusO The computer runs slower than usual. O The computer stops responding, or it locks up frequently. O The computer crashes, and then it restarts every few minutes. O The computer restarts on its own. Additionally, the computer does not run as usual. O Applications on the computer do not work correctly. O Disks or disk drives are inaccessible. O You cannot print items correctly. O You see unusual error messages. 06/27/13Fundamentals of Computing by Joel Amenya 106
    • 107. Symptoms of a computer virusO You see distorted menus and dialog boxes. O There is a double extension on an attachment that you recently opened, such as a .jpg, .vbs, .gif, or .exe. extension. O An antivirus program is disabled for no reason. Additionally, the antivirus program cannot be restarted. O An antivirus program cannot be installed on the computer, or the antivirus program will not run. 06/27/13Fundamentals of Computing by Joel Amenya 107
    • 108. Symptoms of a computer virus O New icons appear on the desktop that you did not put there, or the icons are not associated with any recently installed programs. O Strange sounds or music plays from the speakers unexpectedly. O A program disappears from the computer even though you did not intentionally remove the program. 06/27/13Fundamentals of Computing by Joel Amenya 108
    • 109. How to eliminate and cub computer virus. O Install an anti-virus examples of antiviruses include:- avast, kaspasky, mcafee, f secure O Keep Microsoft Updates current O Only download from reputable sources. O When downloading free software beware and read the fine print. O Install a firewall O Verify e-mails with attachments from sender. for even higher security block all attachments. 06/27/13Fundamentals of Computing by Joel Amenya 109
    • 110. How to eliminate and cub computer virus.O Do not open attachments with double extensions or extensions with the following .vbs .msi, .pif, .scr O Turn off preview pane in E-mail O Download music and programs from legitimate sources not through warez sites or peer-to-peer file swapping. O Beware of porn sites especially phone dialers. O Get of that joke e-mail list O Have proper back up procedures in place. O Enable Macro prevention in Microsoft Office 06/27/13Fundamentals of Computing by Joel Amenya 110
    • 111. INFORMATION NETWORKS O A computer network is a group of interconnected computers. Advantages of Networks: O Speed. Sharing and transferring files within Networks are very rapid. Thus saving time, while maintaining the integrity of the file. O Cost. Individually licensed copies of many popular software programs can be costly. Networkable versions are available at considerable savings. Shared programs, on a network allows for easier upgrading of the program on one single file server, instead of upgrading individual workstations.  06/27/13Fundamentals of Computing by Joel Amenya 111
    • 112. Advantages of Networks:O Security. Sensitive files and programs on a network are passwords protected (established for specific directories to restrict access to authorized users) or designated as "copy inhibit," so that you do not have to worry about illegal copying of programs. O Centralized Software Management. Software can be loaded on one computer (the file server) eliminating that need to spend time and energy. O Resource Sharing. Resources such as, printers, fax machines and modems can be shared.  06/27/13Fundamentals of Computing by Joel Amenya 112
    • 113. USES OF NETWORKS AND INTERNET O Sharing music and video files O Research and on-line learning O Chatting with friends O Planning vacations O Purchasing gifts and supplies 06/27/13Fundamentals of Computing by Joel Amenya 113
    • 114. Characteristics of a Computer NetworkO The primary purpose of a computer network is to share resources: O You can play a CD music from one computer while sitting on another computer O You may have a computer with a CD writer or a backup system but the other computer doesn’t have it; In this case, you can burn CDs or make backups on a computer that has one of these but using data from a computer that doesn’t have a CD writer or a backup system O You may have a computer that doesn’t have a DVD player. In this case, you can place a movie DVD on the computer that has a DVD player, and then view the movie on a computer that lacks a DVD player 06/27/13Fundamentals of Computing by Joel Amenya 114
    • 115. Characteristics of a Computer Network Cont. O You can connect a printer (or a scanner, or a fax machine) to one computer and let other computers of the network print (or scan, or fax) to that printer (or scanner, or fax machine) O You can place a CD with pictures on one computer and let other computers access those pictures O You can create files and store them in one computer, then access those files from the other computer (s) connected to it 06/27/13Fundamentals of Computing by Joel Amenya 115
    • 116. Disadvantages of Networks O One server breaking down may affect a number of computers O vulnerable to hackers, Crackers and viruses O Cabling and installation may be expensive O a network manager may need to be employed to run the network O Could degrade in performance 06/27/13Fundamentals of Computing by Joel Amenya 116
    • 117. Types of networks O 1.PAN-A personal area network (PAN) is a computer network used for communication among computer and different information technological devices close to one person. O Some examples of devices that are used in a PAN are personal computers, printers, fax machines, telephones, PDAs, scanners, and even video game consoles. A PAN may include wired and wireless devices. The reach of a PAN typically extends to 10 meters. 06/27/13Fundamentals of Computing by Joel Amenya 117
    • 118. Types of networks Cont’ O 2. A local area network (LAN) supplies networking capability to a group of computers in close proximity to each other such as in an office building, a school, or a home. O A LAN is useful for sharing resources like files, printers, games or other applications. O A LAN in turn often connects to other LANs, and to the Internet or other WAN. 06/27/13Fundamentals of Computing by Joel Amenya 118
    • 119. Types of networks Cont’d O A campus network, campus area network, corporate area network or CAN is a computer network made up of an interconnection of local area networks (LANs) within a limited geographical area. The networking equipments (switches, routers) and transmission media (optical fiber, copper plant, Cat5 cabling etc) are almost entirely owned by the campus tenant / owner: an enterprise, university, government etc 06/27/13Fundamentals of Computing by Joel Amenya 119
    • 120. Types of networks Cont’d 2.Wide-Area Network O The term Wide Area Network (WAN) usually refers to a network which covers a large geographical area. O A computer network that spans a relatively large geographical area. O Typically, a WAN consists of two or more local-area networks (LANs). O Computers connected to a wide-area network are often connected through public networks, such as the telephone system. O They can also be connected through leased lines or satellites. O The largest WAN in existence is the Internet. 06/27/13Fundamentals of Computing by Joel Amenya 120
    • 121. Types of networks Cont’d O Global area networkGlobal (GAN)refers to any network that is composed of different interconnected computer networks (WANs) and also covers an unlimited geographical area. O Storage Area Network - connects servers to data storage devices through a technology like Fibre Channel. O System Area Network - links high-performance computers with high-speed connections in a cluster configuration. Also known as Cluster Area Network. 06/27/13Fundamentals of Computing by Joel Amenya 121
    • 122. Network topology O Linear Bus Topology A linear bus topology consists of a main run of cable with a terminator at each end (See fig. 1). All nodes (file server, workstations, and peripherals) are connected to the linear cable. 06/27/13Fundamentals of Computing by Joel Amenya 122
    • 123. Network topology Cont’d O Advantages of a Linear Bus Topology O Easy to connect a computer or peripheral to a linear bus. O Requires less cable length than a star topology. O Disadvantages of a Linear Bus Topology O Entire network shuts down if there is a break in the main cable. O Terminators are required at both ends of the backbone cable. O Difficult to identify the problem if the entire network shuts down. O Not meant to be used as a stand-alone solution in a large building. 06/27/13Fundamentals of Computing by Joel Amenya 123
    • 124. Network topology Cont’d O Ring network topology O A network topology that is set up in a circular fashion in which data travels around the ring in one direction and each device on the right acts as a repeater to keep the signal strong as it travels. Each device incorporates a receiver for the incoming signal and a transmitter to send the data on to the next device in the ring. The network is dependent on the ability of the signal to travel around the ring. 06/27/13Fundamentals of Computing by Joel Amenya 124
    • 125. Network topology Cont’d O Star O A star topology is designed with each node (file server, workstations, and peripherals) connected directly to a central network hub, switch, or concentrator (See fig. 2). O Data on a star network passes through the hub, switch, or concentrator before continuing to its destination. The hub, switch, or concentrator manages and controls all functions of the network. It also acts as a repeater for the data flow. This configuration is common with twisted pair cable; however, it can also be used with coaxial cable or fiber optic cable. 06/27/13Fundamentals of Computing by Joel Amenya 125
    • 126. Network topology Cont’d O Star topology 06/27/13Fundamentals of Computing by Joel Amenya 126
    • 127. Network topology Cont’d O Advantages of a Star Topology O Easy to install and wire. O No disruptions to the network when connecting or removing devices. O Easy to detect faults and to remove parts. O Disadvantages of a Star Topology O Requires more cable length than a linear topology. O If the hub, switch, or concentrator fails, nodes attached are disabled. O More expensive than linear bus topologies because of the cost of the hubs, etc. 06/27/13Fundamentals of Computing by Joel Amenya 127
    • 128. Network topology Cont’dO Tree or Expanded Star O A tree topology combines characteristics of linear bus and star topologies. It consists of groups of star-configured workstations connected to a linear bus backbone cable (See fig. 3). Tree topologies allow for the expansion of an existing network, and enable schools to configure a network to meet their needs. 06/27/13Fundamentals of Computing by Joel Amenya 128
    • 129. Network topology Cont’d 06/27/13Fundamentals of Computing by Joel Amenya 129
    • 130. Network topology Cont’d Advantages of a Tree Topology O Point-to-point wiring for individual segments. O Supported by several hardware and software venders. Disadvantages of a Tree Topology O Overall length of each segment is limited by the type of cabling used. O If the backbone line breaks, the entire segment goes down. O More difficult to configure and wire than other topologies. 06/27/13Fundamentals of Computing by Joel Amenya 130
    • 131. Network topology Cont’d 06/27/13Fundamentals of Computing by Joel Amenya 131
    • 132. Network topology Cont’dO Mesh Topology Mesh topologies involve the concept of routes. Unlike each of the previous topologies, messages sent on a mesh network can take any of several possible paths from source to destination. (Recall that even in a ring, although two cable paths exist, messages can only travel in one direction.) Some WANs, most notably the Internet, employ mesh routing. O A mesh network in which every device connects to every other is called a full mesh. As shown in the illustration below, partial mesh networks also exist in which some devices connect only indirectly to others. 06/27/13Fundamentals of Computing by Joel Amenya 132
    • 133. INTRODUCTION TO WINDOWS OPERATING SYSTEM Starting, Shutting Down And Restarting Windows Turning on the PC O Most PCs will have a single switch in the front that is activated to provide power. O The monitor will also have a power switch in most cases. Usually this is in the front or lower right portion of the display case. O The startup process of a computer is also referred to as booting the system. There are two types: O A cold boot is performed when the PC is turned on using the power button. O At the end of this process, the Windows operating system desktop will be displayed. O Before starting your computer make sure you do not have a diskette in your A drive 06/27/13Fundamentals of Computing by Joel Amenya 133
    • 134. Shutting Down a Computer O To shutdown the computer, click on the Start button on the lower left corner of the Windows Taskbar, and select Shut Down. O Alternatively, press Ctrl-Alt-Delete and click Shut Down from the menu that displays. O Do not switch the computer off until a message displays indicating that it is safe to do so. O Important data that is stored in memory while the system is operating needs to be written to the hard disk before switching off the computer. O Newer computers will automatically shut off power when the shutdown process is complete. O NOTE: It is extremely important not to power off the computer with the power switch. Most operating systems like Macintosh and Windows have a specific method for turning the system off. In Windows, choose the Shut Down button from the Start menu. On a Macintosh, choose the Shut Down button from the Special menu06/27/13Fundamentals of Computing by Joel Amenya 134
    • 135. Restarting the PC O Restarting a PC that has already been powered up is referred to as a warm boot. O This can be achieved by pressing the reset button on the front panel. O Alternatively, press Ctrl- Alt-Delete, and click Restart from the menu that displays. O Sometimes your computer will start doing funny things or your mouse will stop working O Try ALT + CTL + DELETE O If you see a program is not responding, you can try to highlight that program and press the “End Task” button. O If nothing happens try ALT + CTL + DELETE again. This will restart your computer 06/27/13Fundamentals of Computing by Joel Amenya 135
    • 136. Mouse O Pointing device that moves pointer or cursor O Point and click (tip of the arrow is the point) O Left and right buttons O Start programs - 1 click vs 2 clicks O Highlight text (click and drag) O Practice makes perfect 06/27/13Fundamentals of Computing by Joel Amenya 136
    • 137. Cursor Types O Arrow O Busy O Text O Double arrow O Hand 06/27/13Fundamentals of Computing by Joel Amenya 137
    • 138. The Desktop O The main display screen in Windows is known as the desktop. O IT refers to the main background area. O You can customize your desktop in various ways, including adding a background picture, changing the background colour, and changing the size of the icons on the desktop. 06/27/13Fundamentals of Computing by Joel Amenya 138
    • 139. The Desktop 06/27/13Fundamentals of Computing by Joel Amenya 139
    • 140. Features of a Desktop O Icons are small graphical images that can represent your computer's programs, files, folders and printers amongst other things O To activate the program/file/folder that an icon represents you simply double click (two clicks in quick succession) on it with the left mouse button. O This will activate the icon and either start a program or open a file/folder. O It can also be non selectable as in a company logo on a web page. O Some of the icons on the desktop, such as My Computer, Network Neighbourhood, My Network Places, Recycle Bin, or My Documents, are shortcuts to those directories. O Other icons that may be on the desktop, such as Microsoft Word, Excel, or Adobe Photoshop, are shortcuts to those applications. O The My Computer icon gives access to all the installed drives, which are computer storage components. 06/27/13Fundamentals of Computing by Joel Amenya 140
    • 141. Features of a Desktop O Recycle Bin When you delete a file, Windows XP will place the file into the recycle bin (instead of deleting it altogether), this allows you to restore the file in case you deleted it by mistake. 06/27/13Fundamentals of Computing by Joel Amenya 141
    • 142. Start button O Clicking on the start button opens up what is called the start menu, the start menu is used to access your programs, settings, printers and almost all functions on PC. O The quick launch buttons are located on the taskbar next to the Start button. O These buttons allow immediate access to the desktop from any application, as well as access to Internet Explorer and Outlook Express. 06/27/13Fundamentals of Computing by Joel Amenya 142
    • 143. Start Menu OverviewO Log off - Log off the current user. O Turn Off Computer - shutdown, restart and standby. O All Programs - Access to installed programs. O Run - Used to manually start executable files (programs). O Search - Search your PC for pictures, music, documents, files and folders. O Help and Support - Opens the built-in Windows help system, including various help and support topics. O You can control windows updates and also request remote assistance from a friend/colleague via the internet or network. O Printers and Faxes - Access to your printers and faxes folder, allows you to add and configure printers/faxes. O Control Panel - The control panel is used to configure various Windows XP settings. We will be looking at the Win XP control panel in detail later in the tutorial. 06/27/13Fundamentals of Computing by Joel Amenya 143
    • 144. Start Menu Overview O My Computer - Gives you access to your computer's disk drives and files. O My Music - Links to a folder created by Windows XP which is used (by default) to store any music files on your hard drive. O My Pictures - Links to a folder (again created by Windows XP) used (by default) to store any pictures/images on your hard drive. O My Recent Documents - This folder contains any recently viewed documents. O My Documents - Gives access to a folder created by Windows XP which is used (by default) to store any documents on your hard drive. 06/27/13Fundamentals of Computing by Joel Amenya 144
    • 145. Start Menu Overview O Tour Windows XP - Starts the built- in tour of Windows XP's features. O Windows Movie Maker - Opens Windows XP's movie editing software. O Outlook Express - Opens the Outlook Express mail program. O Files and Settings Transfer Wizard - Allows you to import or export your files and settings from or to a different installation of Windows XP. 06/27/13Fundamentals of Computing by Joel Amenya 145
    • 146. The All Programs Menu O When you hover the mouse over All Programs on the start menu, you will see a menu appear. O The menu gives you access to the programs currently installed on your PC. O Your menu will be different from our example, as you will have different programs installed on your PC. O To open a program simply left click on it with the left mouse button. O Notice some options have a small black arrow to the right hand side, this indicates that it contains another sub-menu. 06/27/13Fundamentals of Computing by Joel Amenya 146
    • 147. All program menu cont. O You can rename any program on the menu by right clicking on it and selecting rename from the menu that appears. O After installing new software it will (usually) appear on the programs menu. O To remove a program from the All Programs menu simply right click on it and select delete. O NOTE: if you want to uninstall a program then use the control panel to uninstall it. O Simply deleting it from the programs menu will not uninstall the software. 06/27/13Fundamentals of Computing by Joel Amenya 147
    • 148. The Task Bar O Start Button - The Start Button is used to access the Windows XP start menu O Window Tabs - The Windows tabs are used to switch between any open windows (programs, folders, documents, etc). O You can switch between the windows by simply clicking on the corresponding window tab, clicking a second time on the same tab will minimize the window. 06/27/13Fundamentals of Computing by Joel Amenya 148
    • 149. Features of a Task bar O Grouping Window Tabs - When the taskbar fills up with window tabs it can group all files/windows within a single program into just one window tab. In other words, if you have 2 documents open in Word, you will only have one tab on the taskbar (instead of 2). O You can then access each document by left clicking on the tab and selecting the file/window you want from the menu that appears. O This feature can be switched off by right clicking on the taskbar, clicking on properties and then unchecking the box next to Group similar taskbar buttons. O System Tray - The system tray displays icons for programs that are loaded into memory, although not all programs place an icon in this tray 06/27/13Fundamentals of Computing by Joel Amenya 149
    • 150. Features of a Task Bar O The Quick Launch Bar By default, Windows XP has the quick launch bar hidden, if you want to use the quick launch bar you need to activate it. O To do this simply right click on the taskbar, hover the mouse pointer over toolbars and then put a tick in the box next to Quick Launch. The Windows XP quick launch bar provides direct access to your programs, files or folders with just one click. O It is bar is visible (by default) even when you have a window open. 06/27/13Fundamentals of Computing by Joel Amenya 150
    • 151. Task Bar Cont. O When you first enable the quick launch bar there are normally a couple of icons visible: - Show Desktop Icon - This icon is used to minimise all open windows to show the windows xp desktop, clicking again will restore the windows to their previous state. - Internet Explorer Icon -This icon will open Microsoft's Internet Explorer browser. Adding icons to quick launch bar O Simply drag the icon of the program/file/folder over the quick launch bar and drop it (release the mouse button). O If you add or delete icons you can increase or decrease the size of the quick launch bar by moving the divider O To delete an icon from it , Right click on the icon you want to delete and then select delete from the menu that appears. 06/27/13Fundamentals of Computing by Joel Amenya 151
    • 152. Explorer O Windows Explorer is an application that provides detailed information about your files, folders, and drives. O It is also the component of the operating system that presents the user interface on the monitor and enables the user to control the computer. O It is sometimes referred to as the Windows Shell, or simply “Explorer”. O You can use it to see how your files are organized and to copy, move, and rename files, as well as perform other tasks pertaining to files, folders, and drives. 06/27/13Fundamentals of Computing by Joel Amenya 152
    • 153. Opening Explorer O The simplest way to access Windows Explorer is to right-click the Start menu or the My Computer icon and select Explore. O OR hold down the START button and press the E key. O Or click the START button, click run, type explorer into the box and press enter. O Or open My Computer and click on the Folders button at the top of the My Computer environment. O In newer operating systems, it is under Accessories. 06/27/13Fundamentals of Computing by Joel Amenya 153
    • 154. Copying, Deleting, and Renaming Files and FoldersO All of these tasks are straight forward and can be achieved by right clicking in a folder where you want to make the action. You will be presented with the window below; 06/27/13Fundamentals of Computing by Joel Amenya 154
    • 155. Working With Icons O Creating Shortcuts (Icons) O Go to the program or file in Windows Explorer. Right-click the program or file and select Create Shortcut O OR Right-click on the desktop and select New > New Shortcut or Create Shortcut. O Enter the path for the program or file, and the shortcut will display on the desktop. 06/27/13Fundamentals of Computing by Joel Amenya 155
    • 156. Working With IconsO Moving Icons O To move the created icon or another desktop icon to another position on the desktop, click on it and then drag it to the desired location. The icon becomes semi- transparent while being dragged. To restore the icon to full intensity, click outside of it. If the icon does not move, disable the Auto Arrange function on the desktop. O To do this, right-click on an empty space of the desktop and uncheck the Auto Arrange selection. Shortcut icons can be created for frequently used programs such as web browsers, word processors, spreadsheets, and instant messengers. 06/27/13Fundamentals of Computing by Joel Amenya 156
    • 157. Working with Icons O Selecting Multiple Icons O To simultaneously select and move several icons, hold down the Ctrl key and click on all the icons that are to be moved. Then drag the group of icons to the new location and let go of the mouse button. De-select the icons by clicking on an empty part of the desktop. O Renaming Icons O There are two ways to rename an icon; O The first way is to simply click once on the name under the icon, then type in a new name. Click on an empty part of the desktop to complete the action. O The second ways is to right-click on the icon and select the Rename option. O Navigating and working with the desktop is easier with the use of icons. Since icons are simply shortcuts that point to programs and files, they can be copied, moved, and even deleted without affecting the program or file. 06/27/13Fundamentals of Computing by Joel Amenya 157
    • 158. Scrolling pages O Mouse O Click on up and down arrows or O Click on top of and below that darker box without touching the box or O Click and drag the darker box O Keyboard (make sure cursor is on page by clicking on empty space) O Use arrow keys O Use page up, page down, home and end 06/27/13Fundamentals of Computing by Joel Amenya 158
    • 159. Opening Programs O If on desktop as icon, double click on icon. If does not open press “Enter” key. O Click on “Start” button, Move cursor up to “Programs”. After menu on the right appears move cursor over to menu and up or down to required program. Click on program O If program has been minimized and appears on task bar, click on square representing program. 06/27/13Fundamentals of Computing by Joel Amenya 159
    • 160. SDLC and Related Methodologies
    • 161. Contemplative Questions O What are the various approaches to developing Information Systems? O Is there one best way? O What is the difference between techniques, methodologies and tools? O What does the popular term “SDLC” actually mean?
    • 162. SDLC O SDLC stands for O Systems O Development O Life O Cycle O What does it mean?
    • 163. SDLC O SDLC stands for O Systems Development Life Cycle O First, SDLC is a Life Cycle. O All systems have a life cycle or a series of stages they naturally undergo.  O The number and name of the stages varies, but the primary stages are conception, development, maturity and decline. O The systems development life cycle (SDLC) therefore, refers to the development stage of the system’s life cycle. Why are we so interested in the development stage? What about conception, maturity and decline?
    • 164. Typical Reasons to Initiate a Systems Development Project Desire to make more effective use of information Problems with existing systems Desire to exploit new opportunities Increasing competition Organizational growth Merger or acquisition Change in market or external environment Perception of potential benefit by individual capable of initiating change Systems development process initiated
    • 165. Methodologies O Is there a difference between the term SDLC and the term ‘methodology’? O Whereas the SDLC refers to a stage all systems naturally undergo, a methodology refers to an approach invented by humans to manage the events naturally occurring in the SDLC.  O A methodology is, in simple terms, a set of steps, guidelines, activities and/or principles to follow in a particular situation. O Most methodologies are comprehensive, multi-step approaches to systems development O There are many methodologies out there. See www.methodology.org .
    • 166. SDLC vs. Methodology O It is confusing, but unfortunately, the term SDLC is frequently used synonymously with the waterfall or traditional approach for developing information systems. O “The SDLC approach” O This approach essentially refers to a linear sequence of stages to develop a system from planning to analysis to design to implementation.  O Stages are followed from beginning to end.  O Revisiting prior stages is not permitted. 
    • 167. Databases and Application Independence O Database O Shared collection of logically related data O Organized to facilitate capture, storage and retrieval by multiple users O Centrally managed O Designed around subjects such as Customers or Suppliers O Application Independence O Separation of data from the applications, e.g. O Payroll data is part of the enterprise-wide data model and can be used by many systems, not just the Payroll System
    • 168. Systems Development Life Cycle O Every textbook has different names for the stages of the SDLC O Usually they stages are O Planning (just after Conception) O Analysis O Design O Implementation O Maintenance (starting Maturity) 1. 168
    • 169. Systems Development Life Cycle O This text highlights 6 distinct phases: O Project Identification and Selection O Project Initiation and Planning O Analysis O Design O Implementation O Maintenance
    • 170. Stages of the SDLC IS 421 System s Analysis IS 422 System s Design
    • 171. Phases of the Systems Development Life Cycle 1. Project Identification and Selection O Two Main Activities O Identification of need O Prioritization and translation of need into a development schedule O Helps organization to determine whether or not resources should be dedicated to a project. 1. Project Initiation and Planning O Two Activities O Formal preliminary investigation of the problem at hand O Presentation of reasons why system should or should not be developed by the organization
    • 172. Systems Development Life Cycle O Analysis O Study of current procedures and information systems O Determine requirements O Study current system O Structure requirements and eliminate redundancies O Generate alternative designs O Compare alternatives O Recommend best alternative
    • 173. Systems Development Life Cycle O Design O Logical Design O Concentrates on business aspects of the system O Physical Design O Technical specifications O Implementation O Implementation O Hardware and software installation O Programming O User Training O Documentation
    • 174. Systems Development Life Cycle O Maintenance O System changed to reflect changing conditions O System obsolescence A good way to learn the stages of the SDLC is to create deliverables (output) of each stage in the process.
    • 175. Alternative Approaches O Prototyping O Building a scaled-down working version of the system O Advantages: O Users are involved in design O Captures requirements in concrete form O Rapid Application Development (RAD) O Utilizes prototyping to delay producing system design until after user requirements are clear
    • 176. Prototyping Fig. 1-6
    • 177. Alternative Approaches O Joint Application Design (JAD) O Users, Managers and Analysts work together for several days O System requirements are reviewed O Structured meetings O We will see a video on this when we cover Chapter 7
    • 178. Alternative Approaches O Evolutionary or spiral methodology The *** never gets done! Different versions, always in different stages.