chapter 10 software of a computer system

Chapter 10 Chapter 10 Software of a Computer SystemSoftware of a Computer System

10.1 Application Software 172

10.2 System Software 174

10.1 Application Software10.1 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

Chapter 10 Software

Application Software Application Software

10.1.1 10.1.1 Productivity softwareProductivity 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


10.1.210.1.2 Graphic and multimedia softwareGraphic 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.



10.1.310.1.3 Home, Personal and Educational SoftwareHome, 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.



10.1.410.1.4 Communication SoftwareCommunication 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.


10.2 System Software10.2 System Software

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

Chapter 10 Software

System SoftwareSystem Software 10.2.1 10.2.1 Operating SystemOperating System (1)(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 SoftwareSystem Software 10.2.1 10.2.1 Operating SystemOperating System (2)(2)

❚ For the personal computers, the most popular operating systems are

❘ Windows

❘ MAC OS

❘ Linux

❘ IBM OS/2 etc.

❚ 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


Operating SystemOperating System

10.2.1.110.2.1.1 Functions of an OS (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



❚ 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




❚ 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




❚ 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.




❚ 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 demandinguses a lot of processing power, memory, and disk space

requires a good graphical display device;

(2) Slow for the experienced users




❚ 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




❚ 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!


System SoftwareSystem Software 10.2.2 10.2.2 Utility programs (1)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


System SoftwareSystem Software 10.2.2.1 10.2.2.1 Utility programs (2)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


❚ 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



❚ 3. Diagnostic utilities❙ Diagnosing problems

❙ Reporting errors

❙ Suggesting course of action

❙ Example ❘ Dr. Watson (included in Windows)


System SoftwareSystem Software 10.2.2.4-6 Utility programs (5)10.2.2.4-6 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



❚ 7. Backup utilities❙ Copying selected files or entire hard disk

❙ onto a removable storage medium, like a tape

❙ The reverse of backup is restoring



❚ 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



❚ 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


System SoftwareSystem Software 10.2.3 10.2.3 Driver ProgramsDriver 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


chapter 10 software of a computer system

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