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Chapter 10 Software of a Computer System 10.1 Application Software 172 10.2 System Software 174 Chapter 10 Software 10.1 Application Software Application software also called applications Programs that perform tasks for users A set of tools for completing a specific type of job
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Chapter 10 Software of a Computer System 10.1 Application Software 172 10.2 System Software 174
Chapter 10 Software 10.1 Application 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
10.1 Application Software Application Software10.1.1 Productivity 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.
10.1 Application Software Application Software10.1.2Graphic and multimedia 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.
10.1 Application Software Application Software10.1.3Home, Personal and Educational 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.
10.1 Application Software Application Software10.1.4Communication 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.
Chapter 10 Software 10.2 System Software • System software includes three types: • 1. Operating System • 2. Utility Programs • 3. Driver Programs
10.2 System Software System Software10.2.1 Operating System(1) • 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
10.2 System Software System Software10.2.1 Operating System(2) • For the personal computers, the most popular operating systems are • Windows • MAC OS • Linux • IBM OS/2etc. • 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
10.2.1 Operating System Operating System10.2.1.1 Functions of an OS (1) • 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.
10.2.1 Operating System Operating System10.2.1.2 Functions of an OS (2) • 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
10.2.1 Operating System Operating System10.2.1.3 Functions of an OS (3) • 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
10.2.1 Operating System Operating System10.2.1.3 Functions of an OS (4) • 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.
10.2.1 Operating System Operating System10.2.1.3 Functions of an OS (5) • 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
10.2.1 Operating System Operating System10.2.1.4 Functions of an OS (6) • 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
10.2.1 Operating System Operating System10.2.1.5 Functions of an OS (7) • 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!
10.2 System Software System Software10.2.2 Utility programs (1) • 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
10.2.2 Utility Programs System Software10.2.2.1 Utility programs (2) • 1. File viewers • Displaying lists of directories and files in storage • Copying, deleting and renaming files • Example • File Explorer included in Windows.
10.2.2 Utility Programs System Software10.2.2.2 Utility programs (3) • 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
10.2.2 Utility Programs System Software10.2.2.3 Utility programs (4) • 3. Diagnostic utilities • Diagnosing problems • Reporting errors • Suggesting course of action • Example • Dr. Watson (included in Windows)
10.2.2 Utility Programs System Software10.2.2.4-6 Utility programs (5) • 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
10.2.2 Utility Programs System Software10.2.2.7 Utility programs (6) • 7. Backup utilities • Copying selected files or entire hard disk • onto a removable storage medium, like a tape • The reverse of backup is restoring
10.2.2 Utility Programs System Software10.2.2.8 Utility programs (7) • 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
10.2.2 Utility Programs System Software10.2.2.9 Utility programs (8) • 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
10.2 System Software System Software10.2.3 Driver Programs • 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