Chapter 10 Software of a Computer System

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Chapter 10 Software of a Computer System

• 10.1 Application Software 172
• 10.2 System Software 174

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10.1 Application Software
Chapter 10 Software

• Application software
• also called applications
• Programs that perform tasks for users
• A set of tools for completing a specific type of
  job
• 1. Productivity Software
• 2. Graphic and Multimedia Software
• 3. Home, Personal and Educational Software
• 4. Communication Software

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Application Software 10.1.1 Productivity
software
10.1 Application Software

• Productivity software
• also called business software
• Increases effectiveness/efficiency of routine
  clerical work
• e.g. typing, calculation, charting, record
  handling, presentation and scheduling etc.
• Including software for
• Word processing
• Spreadsheet
• Accounting
• Database
• Presentation
• Desktop publishing etc.

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Application Software 10.1.2 Graphic and
multimedia software
10.1 Application Software

• Graphic and multimedia software
• Creating/editing multimedia elements
• e.g. graphics, animation, sound and video
• Including software for
• computer-aided design
• desktop publishing
• vector/bitmap graphic editing
• audio/video editing
• multimedia authoring
• Web page authoring etc.

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Application Software 10.1.3 Home, Personal
and Educational Software
10.1 Application Software

• Software for home users includes
• home design
• tax preparation
• entertainment etc.
• Software for personal use includes
• personal finance
• legal
• personal information manager etc.
• Software for educational use includes
• CAI (computer-aided instruction)
• CAL (computer-aided learning)
• clip art/image gallery and encyclopedia etc.

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Application Software 10.1.4 Communication
Software
10.1 Application Software

• Communication software
• Enable people to communicate and share
  information with others
• Including
• e-mail
• Web browsers
• chat rooms
• newsgroups
• instant messaging
• FTP programs etc.

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10.2 System Software
Chapter 10 Software

• System software includes three types
• 1. Operating System
• 2. Utility Programs
• 3. Driver Programs

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System Software 10.2.1 Operating System (1)
10.2 System Software

• Operating system (OS)
• A set of programs
• Controlling the operation of a computer system
• Managing resources
• Providing an interface between users and hardware
• Without an OS, the programmer have to
• handle ALL basic functions
• e.g. displaying text on a screen, sending output
  to a printer or writing disk files

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System Software 10.2.1 Operating System (2)
10.2 System Software

• For the personal computers, the most popular
  operating systems are
• Windows
• MAC OS
• Linux
• IBM OS/2?
• Functions of an OS
• 1. Controlling the operations of a computer
  system
• 2. Managing resources
• 3. Providing an user interface
• 4. Other tasks
• 5. Time-sharing

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Operating System10.2.1.1 Functions of an OS (1)
10.2.1 Operating System

• 1. Controlling the operations of Hardware
• An OS controls the operations of peripherals
• (1) recognizing input from keyboard
• (2) sending output to display
• (3) keeping track of files and directories
• (4) communicating with other computers.
• An OS also controls the operation of CPU
• (1) scheduling of programs
• (2) allocating memory
• (3) loading of the programs
• (4) controlling program execution.

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Operating System10.2.1.2 Functions of an OS (2)
10.2.1 Operating System

• 2. Managing resources
• An executing program is known as a process
• Conflicts occur between processes
• when two or more processes require the same
  resource (such as memory or printer)
• Sometimes may lead to system crash
• Solution OS handles all the requests and
  allocates the resources in an orderly manner to
  avoid crash and improve efficiency.
• Multi-tasking
• Load more than one program and switch from one
  program to another.
• Through clipboard, data can be transferred
  between applications

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Operating System10.2.1.3 Functions of an OS (3)
10.2.1 Operating System

• 3. User interface
• provide an environment for users to access
  various parts of the computer system easily
• Two types of user interface
• 1. Command line interface
• 2. Graphical user interface

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Operating System10.2.1.3 Functions of an OS (4)
10.2.1 Operating System

• 1. Command line interface
• Using text to give instruction to the OS
• User need to memorise a lot of instructions
• 2. Graphical User Interface (GUI)
• Displays information in windows
• User interacts with the interface using pointing
  device
• Commands from users are issued by clicking
• menu,
• icons,
• buttons or
• other graphical objects.

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Operating System10.2.1.3 Functions of an OS (5)
10.2.1 Operating System

• The advantages of GUI are
• (1) Intuitive, easy to use
• (2) users need not learn a set of instructions to
  operate the system.
• The disadvantages of GUI are
• (1) Resource demanding
• uses a lot of processing power, memory, and disk
  space
• requires a good graphical display device
• (2) Slow for the experienced users

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Operating System10.2.1.4 Functions of an OS (6)
10.2.1 Operating System

• Other tasks of an OS include
• Monitoring performance
• e.g. The memory and CPU usage. OS may warn users
  if the resources in the computer system get low.
• Maintaining security
• e.g. Allowing only authorised users to log on the
  system
• Controlling the network
• e.g. A File server controls access to a network
  and provides centralised storage area.
• Communicating with other OS
• e.g. A Web server may respond to computers with
  Windows or MAC OS

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Operating System10.2.1.5 Functions of an OS (7)
10.2.1 Operating System

• 5. Time sharing
• For large systems,
• e.g. Mainframe/Minicomputer
• Suppose there are 100 users,
• each given a time slice of 0.01 s to interact
  with CPU
• i.e. each user is served 0.01 s in every second.
• However, all of them will think that they have
  sole use of the computer!

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System Software 10.2.2 Utility programs (1)
10.2 System Software

• Utility programs (or utilities)
• Allowing users to manage devices and programs
• Should be run regularly
• Some come with the OS
• Examples
• File viewer, File compression utility, Diagnostic
  utility, Uninstaller, Disk scanner, File
  defragmenter, Backup utility, Screen saver,
  Anti-virus program

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System Software 10.2.2.1 Utility programs (2)
10.2.2 Utility Programs

• 1. File viewers
• Displaying lists of directories and files in
  storage
• Copying, deleting and renaming files
• Example
• File Explorer included in Windows.

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System Software 10.2.2.2 Utility programs (3)
10.2.2 Utility Programs

• 2. File compression utilities
• Reducing the size of a file
• while keeping the content unchanged
• So that
• files take up less storage space
• faster file transmission
• Examples
• WinZip and Stuffit

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System Software 10.2.2.3 Utility programs (4)
10.2.2 Utility Programs

• 3. Diagnostic utilities
• Diagnosing problems
• Reporting errors
• Suggesting course of action
• Example
• Dr. Watson (included in Windows)

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System Software 10.2.2.4-6 Utility programs (5)
10.2.2 Utility Programs

• 4. Uninstallers
• Removing applications
• 5. Disk scanners
• Detecting and correcting problems on disks
• 6. File defragmenters
• Reorganising files and unused space on a hard
  disk
• to improve file access

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System Software 10.2.2.7 Utility programs (6)
10.2.2 Utility Programs

• 7. Backup utilities
• Copying selected files or entire hard disk
• onto a removable storage medium, like a tape
• The reverse of backup is restoring

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System Software 10.2.2.8 Utility programs (7)
10.2.2 Utility Programs

• 8. Screen savers
• Displaying a moving image/blank screen, if idle
  for a specified time
• to prevent images permanently etched on the
  screen
• Provide security
• If the computer is idle for a certain period,
• assume that the user has left his/her seat, then
• lock the computer to prevent unauthorised access

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System Software 10.2.2.9 Utility programs (8)
10.2.2 Utility Programs

• 9. Anti-virus programs
• Search the memory, hard disk and incoming files
  for viruses and
• remove them
• Ensure that e-mail attachment with virus will not
  be saved or executed
• (For e-mail, viruses mainly exist in the
  attachement)
• Auto-update feature
• Download profiles of new viruses

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System Software 10.2.3 Driver Programs
10.2 System Software

• Driver programs
• also called device drivers
• Add-on codes for extending an OS
• Once installed, becomes part of the OS
• Designed for peripherals devices
• Providing facts about the devices
• A driver program may
• exist in the OS or
• come with the device