Chapter 10 Software of a Computer System


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Chapter 10 Software of a Computer System

  1. 1. Chapter 10 Software of a Computer System 10.1 Application Software 172 10.2 System Software 174
  2. 2. 10.1 Application Software <ul><li>Application software </li></ul><ul><ul><li>also called applications </li></ul></ul><ul><ul><li>Programs that perform tasks for users </li></ul></ul><ul><ul><li>A set of tools for completing a specific type of job </li></ul></ul><ul><li>1. Productivity Software </li></ul><ul><li>2. Graphic and Multimedia Software </li></ul><ul><li>3. Home, Personal and Educational Software </li></ul><ul><li>4. Communication Software </li></ul>Chapter 10 Software
  3. 3. Application Software 10.1.1 Productivity software <ul><li>Productivity software </li></ul><ul><ul><li>also called business software </li></ul></ul><ul><ul><li>Increases effectiveness/efficiency of routine clerical work </li></ul></ul><ul><ul><ul><li>e.g. typing, calculation, charting, record handling, presentation and scheduling etc. </li></ul></ul></ul><ul><ul><li>Including software for </li></ul></ul><ul><ul><ul><li>Word processing </li></ul></ul></ul><ul><ul><ul><li>Spreadsheet </li></ul></ul></ul><ul><ul><ul><li>Accounting </li></ul></ul></ul><ul><ul><ul><li>Database </li></ul></ul></ul><ul><ul><ul><li>Presentation </li></ul></ul></ul><ul><ul><ul><li>Desktop publishing etc. </li></ul></ul></ul>10.1 Application Software
  4. 4. Application Software 10.1.2 Graphic and multimedia software <ul><li>Graphic and multimedia software </li></ul><ul><ul><li>Creating/editing multimedia elements </li></ul></ul><ul><ul><ul><li>e.g. graphics, animation, sound and video </li></ul></ul></ul><ul><ul><li>Including software for </li></ul></ul><ul><ul><ul><li>computer-aided design </li></ul></ul></ul><ul><ul><ul><li>desktop publishing </li></ul></ul></ul><ul><ul><ul><li>vector/bitmap graphic editing </li></ul></ul></ul><ul><ul><ul><li>audio/video editing </li></ul></ul></ul><ul><ul><ul><li>multimedia authoring </li></ul></ul></ul><ul><ul><ul><li>Web page authoring etc. </li></ul></ul></ul>10.1 Application Software
  5. 5. Application Software 10.1.3 Home, Personal and Educational Software <ul><ul><li>Software for home users includes </li></ul></ul><ul><ul><ul><li>home design </li></ul></ul></ul><ul><ul><ul><li>tax preparation </li></ul></ul></ul><ul><ul><ul><li>entertainment etc. </li></ul></ul></ul><ul><ul><li>Software for personal use includes </li></ul></ul><ul><ul><ul><li>personal finance </li></ul></ul></ul><ul><ul><ul><li>legal </li></ul></ul></ul><ul><ul><ul><li>personal information manager etc. </li></ul></ul></ul><ul><ul><li>Software for educational use includes </li></ul></ul><ul><ul><ul><li>CAI (computer-aided instruction) </li></ul></ul></ul><ul><ul><ul><li>CAL (computer-aided learning) </li></ul></ul></ul><ul><ul><ul><li>clip art/image gallery and encyclopedia etc. </li></ul></ul></ul>10.1 Application Software
  6. 6. Application Software 10.1.4 Communication Software <ul><li>Communication software </li></ul><ul><ul><li>Enable people to communicate and share information with others </li></ul></ul><ul><ul><li>Including </li></ul></ul><ul><ul><ul><li>e-mail </li></ul></ul></ul><ul><ul><ul><li>Web browsers </li></ul></ul></ul><ul><ul><ul><li>chat rooms </li></ul></ul></ul><ul><ul><ul><li>newsgroups </li></ul></ul></ul><ul><ul><ul><li>instant messaging </li></ul></ul></ul><ul><ul><ul><li>FTP programs etc. </li></ul></ul></ul>10.1 Application Software
  7. 7. 10.2 System Software <ul><li>System software includes three types: </li></ul><ul><li>1. Operating System </li></ul><ul><li>2. Utility Programs </li></ul><ul><li>3. Driver Programs </li></ul>Chapter 10 Software
  8. 8. System Software 10.2.1 Operating System (1) <ul><li>Operating system (OS) </li></ul><ul><ul><li>A set of programs </li></ul></ul><ul><ul><li>Controlling the operation of a computer system </li></ul></ul><ul><ul><li>Managing resources </li></ul></ul><ul><ul><li>Providing an interface between users and hardware </li></ul></ul><ul><li>Without an OS, the programmer have to </li></ul><ul><ul><li>handle ALL basic functions </li></ul></ul><ul><ul><ul><li>e.g. displaying text on a screen, sending output to a printer or writing disk files </li></ul></ul></ul>10.2 System Software
  9. 9. System Software 10.2.1 Operating System (2) <ul><li>For the personal computers, the most popular operating systems are </li></ul><ul><ul><ul><li>Windows </li></ul></ul></ul><ul><ul><ul><li>MAC OS </li></ul></ul></ul><ul><ul><ul><li>Linux </li></ul></ul></ul><ul><ul><ul><li>IBM OS/2 etc. </li></ul></ul></ul><ul><li>Functions of an OS </li></ul><ul><ul><li>1. Controlling the operations of a computer system </li></ul></ul><ul><ul><li>2. Managing resources </li></ul></ul><ul><ul><li>3. Providing an user interface </li></ul></ul><ul><ul><li>4. Other tasks </li></ul></ul><ul><ul><li>5. Time-sharing </li></ul></ul>10.2 System Software
  10. 10. Operating System Functions of an OS (1) <ul><li>1. Controlling the operations of Hardware </li></ul><ul><ul><li>An OS controls the operations of peripherals: </li></ul></ul><ul><ul><ul><li>(1) recognizing input from keyboard; </li></ul></ul></ul><ul><ul><ul><li>(2) sending output to display; </li></ul></ul></ul><ul><ul><ul><li>(3) keeping track of files and directories; </li></ul></ul></ul><ul><ul><ul><li>(4) communicating with other computers. </li></ul></ul></ul><ul><ul><li>An OS also controls the operation of CPU: </li></ul></ul><ul><ul><ul><li>(1) scheduling of programs; </li></ul></ul></ul><ul><ul><ul><li>(2) allocating memory; </li></ul></ul></ul><ul><ul><ul><li>(3) loading of the programs; </li></ul></ul></ul><ul><ul><ul><li>(4) controlling program execution. </li></ul></ul></ul>10.2.1 Operating System
  11. 11. Operating System Functions of an OS (2) <ul><li>2. Managing resources </li></ul><ul><ul><li>An executing program is known as a process </li></ul></ul><ul><ul><li>Conflicts occur between processes </li></ul></ul><ul><ul><ul><li>when two or more processes require the same resource (such as memory or printer) </li></ul></ul></ul><ul><ul><ul><li>Sometimes may lead to system crash </li></ul></ul></ul><ul><ul><ul><li>Solution: OS handles all the requests and allocates the resources in an orderly manner to avoid crash and improve efficiency. </li></ul></ul></ul><ul><ul><li>Multi-tasking </li></ul></ul><ul><ul><ul><li>Load more than one program and switch from one program to another. </li></ul></ul></ul><ul><ul><ul><li>Through clipboard, data can be transferred between applications </li></ul></ul></ul>10.2.1 Operating System
  12. 12. Operating System Functions of an OS (3) <ul><li>3. User interface </li></ul><ul><ul><li>provide an environment for users to access various parts of the computer system easily </li></ul></ul><ul><ul><li>Two types of user interface: </li></ul></ul><ul><ul><li>1. Command line interface </li></ul></ul><ul><ul><li>2. Graphical user interface </li></ul></ul>10.2.1 Operating System
  13. 13. Operating System Functions of an OS (4) <ul><li>1. Command line interface </li></ul><ul><ul><li>Using text to give instruction to the OS </li></ul></ul><ul><ul><li>User need to memorise a lot of instructions </li></ul></ul><ul><li>2. Graphical User Interface (GUI) </li></ul><ul><ul><li>Displays information in windows </li></ul></ul><ul><ul><li>User interacts with the interface using pointing device </li></ul></ul><ul><ul><li>Commands from users are issued by clicking </li></ul></ul><ul><ul><ul><li>menu, </li></ul></ul></ul><ul><ul><ul><li>icons, </li></ul></ul></ul><ul><ul><ul><li>buttons or </li></ul></ul></ul><ul><ul><ul><li>other graphical objects. </li></ul></ul></ul>10.2.1 Operating System
  14. 14. Operating System Functions of an OS (5) <ul><li>The advantages of GUI are: </li></ul><ul><ul><li>(1) Intuitive, easy to use; </li></ul></ul><ul><ul><li>(2) users need not learn a set of instructions to operate the system. </li></ul></ul><ul><li>The disadvantages of GUI are: </li></ul><ul><ul><li>(1) Resource demanding </li></ul></ul><ul><ul><ul><li>uses a lot of processing power, memory, and disk space </li></ul></ul></ul><ul><ul><ul><li>requires a good graphical display device; </li></ul></ul></ul><ul><ul><li>(2) Slow for the experienced users </li></ul></ul>10.2.1 Operating System
  15. 15. Operating System Functions of an OS (6) <ul><li>Other tasks of an OS include: </li></ul><ul><ul><li>Monitoring performance </li></ul></ul><ul><ul><ul><li>e.g. The memory and CPU usage. OS may warn users if the resources in the computer system get low. </li></ul></ul></ul><ul><ul><li>Maintaining security </li></ul></ul><ul><ul><ul><li>e.g. Allowing only authorised users to log on the system </li></ul></ul></ul><ul><ul><li>Controlling the network </li></ul></ul><ul><ul><ul><li>e.g. A File server controls access to a network and provides centralised storage area. </li></ul></ul></ul><ul><ul><li>Communicating with other OS </li></ul></ul><ul><ul><ul><li>e.g. A Web server may respond to computers with Windows or MAC OS </li></ul></ul></ul>10.2.1 Operating System
  16. 16. Operating System Functions of an OS (7) <ul><li>5. Time sharing </li></ul><ul><ul><li>For large systems, </li></ul></ul><ul><ul><ul><li>e.g. Mainframe/Minicomputer </li></ul></ul></ul><ul><ul><li>Suppose there are 100 users, </li></ul></ul><ul><ul><li>each given a time slice of 0.01 s to interact with CPU </li></ul></ul><ul><ul><li>i.e. each user is served 0.01 s in every second. </li></ul></ul><ul><ul><li>However, all of them will think that they have sole use of the computer! </li></ul></ul>10.2.1 Operating System
  17. 17. System Software 10.2.2 Utility programs (1) <ul><li>Utility programs (or utilities) </li></ul><ul><ul><li>Allowing users to manage devices and programs </li></ul></ul><ul><ul><li>Should be run regularly </li></ul></ul><ul><ul><li>Some come with the OS </li></ul></ul><ul><li>Examples </li></ul><ul><li>File viewer , File compression utility , Diagnostic utility , Uninstaller , Disk scanner , File defragmenter , Backup utility , Screen saver , Anti-virus program </li></ul>10.2 System Software
  18. 18. System Software Utility programs (2) <ul><li>1. File viewers </li></ul><ul><ul><li>Displaying lists of directories and files in storage </li></ul></ul><ul><ul><li>Copying, deleting and renaming files </li></ul></ul><ul><ul><li>Example </li></ul></ul><ul><ul><ul><li>File Explorer included in Windows. </li></ul></ul></ul>10.2.2 Utility Programs
  19. 19. System Software Utility programs (3) <ul><li>2. File compression utilities </li></ul><ul><ul><li>Reducing the size of a file </li></ul></ul><ul><ul><ul><li>while keeping the content unchanged </li></ul></ul></ul><ul><ul><li>So that </li></ul></ul><ul><ul><ul><li>files take up less storage space </li></ul></ul></ul><ul><ul><ul><li>faster file transmission </li></ul></ul></ul><ul><ul><li>Examples </li></ul></ul><ul><ul><ul><li>WinZip and Stuffit </li></ul></ul></ul>10.2.2 Utility Programs
  20. 20. System Software Utility programs (4) <ul><li>3. Diagnostic utilities </li></ul><ul><ul><li>Diagnosing problems </li></ul></ul><ul><ul><li>Reporting errors </li></ul></ul><ul><ul><li>Suggesting course of action </li></ul></ul><ul><ul><li>Example </li></ul></ul><ul><ul><ul><li>Dr. Watson (included in Windows) </li></ul></ul></ul>10.2.2 Utility Programs
  21. 21. System Software Utility programs (5) <ul><li>4. Uninstallers </li></ul><ul><ul><li>Removing applications </li></ul></ul><ul><li>5. Disk scanners </li></ul><ul><ul><li>Detecting and correcting problems on disks </li></ul></ul><ul><li>6. File defragmenters </li></ul><ul><ul><li>Reorganising files and unused space on a hard disk </li></ul></ul><ul><ul><li>to improve file access </li></ul></ul>10.2.2 Utility Programs
  22. 22. System Software Utility programs (6) <ul><li>7. Backup utilities </li></ul><ul><ul><li>Copying selected files or entire hard disk </li></ul></ul><ul><ul><li>onto a removable storage medium, like a tape </li></ul></ul><ul><ul><li>The reverse of backup is restoring </li></ul></ul>10.2.2 Utility Programs
  23. 23. System Software Utility programs (7) <ul><li>8. Screen savers </li></ul><ul><ul><li>Displaying a moving image/blank screen , if idle for a specified time </li></ul></ul><ul><ul><li>to prevent images permanently etched on the screen </li></ul></ul><ul><ul><li>Provide security </li></ul></ul><ul><ul><ul><li>If the computer is idle for a certain period, </li></ul></ul></ul><ul><ul><ul><li>assume that the user has left his/her seat, then </li></ul></ul></ul><ul><ul><ul><li>lock the computer to prevent unauthorised access </li></ul></ul></ul>10.2.2 Utility Programs
  24. 24. System Software Utility programs (8) <ul><li>9. Anti-virus programs </li></ul><ul><ul><li>Search the memory, hard disk and incoming files for viruses and </li></ul></ul><ul><ul><li>remove them </li></ul></ul><ul><ul><li>Ensure that e-mail attachment with virus will not be saved or executed </li></ul></ul><ul><ul><li>(For e-mail, viruses mainly exist in the attachement) </li></ul></ul><ul><ul><li>Auto-update feature </li></ul></ul><ul><ul><ul><li>Download profiles of new viruses </li></ul></ul></ul>10.2.2 Utility Programs
  25. 25. System Software 10.2.3 Driver Programs <ul><li>Driver programs </li></ul><ul><ul><li>also called device drivers </li></ul></ul><ul><ul><li>Add-on codes for extending an OS </li></ul></ul><ul><ul><ul><li>Once installed, becomes part of the OS </li></ul></ul></ul><ul><ul><li>Designed for peripherals devices </li></ul></ul><ul><ul><li>Providing facts about the devices </li></ul></ul><ul><ul><li>A driver program may </li></ul></ul><ul><ul><ul><li>exist in the OS or </li></ul></ul></ul><ul><ul><ul><li>come with the device </li></ul></ul></ul>10.2 System Software