CH/S5CIT/Sept. 2006.
System Software, Application Software and Driver Program
USERS
O. S. 2
O. S. 1
HARDWARE
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APPLICATION SOFTWARES
Application Software
i.
is also called user program.
ii.
perform various specific tasks and solve user’s problems.
iii.
e.g. word processing software (Word), spreadsheet package (Excel), database management (Access), web
design tools (Dreamweaver), etc.
System Program
i.
manages the resources of a computer.
ii.
e.g. operating systems, utilities and programming language compilers.
iii.
Utility: It makes the computer system easier to use or to perform highly specialised functions.
Driver Programs
i.
controls peripheral devices such as printers, hard disks, sound cards and so on.
ii.
Each device has its set of specialised commands that only its drive understands.
iii.
Many commonly used drivers such as the keyboard driver are included in the operating system.
iv.
Different operating system may require different drive program for the same device.
Operating System

An operating system (O.S.) is a collection of programs for controlling the resources of a computer system and
provides an interface介面 between the computer and the users or the application programs.

The advantages of using an O.S.
i.
Computer can be operated more effectively and reliably.
ii.
Users need not know the complex operating procedures of the system hardware. Instead, they have to know
only simple commands recognised by the O.S. e.g. DIR/W.
Functions of an O.S.
 User Interface. Provide on-screen elements for users to interact with the computer.

Loading Program. Help users to start a program by loading program into main memory.

Resource Management. Coordinates the working of programs with the hardware:

i.
CPU: Scheduling of Jobs. Jobs are selected for processing according to their priorities.
ii.
Main Memory Management. The O.S. optimises the main memory usage, especially in case of
multiprogramming  several programs are being active executed in the same time in a computer system.
Handling errors. When errors occur, the O.S. makes system interrupts, processes corrective routines where
possible and gives error messages.
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Keeping a log of all programs. It usually keeps a complete record of what has happened during
processing.
*Graphic User Interface (GUI). We control a GUI-based system by pointing and clicking the graphical
objects on the screen with a pointing device such as a mouse. (WIMP – Windows, Icons, Menus and a mouse
Pointer)
Common O. S.

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UNIX.
i.
It is powerful, flexible and runs on many types of computers ranging from supercomputer to PCs.
ii.
It is still a very popular OS for web servers that supports online transactions and make heavy use of
databases.
iii.
It provides a command-line interface. It is not a consumer OS and not easy to learn.
Linux
i.
It is an open source code software. A free copy can be downloaded on the Internet.
ii.
It is a full 32-bit multitasking OS that supports multiple users and multiple processors.
iii.
It supports both command-line and GUI.
DOS.
i.
It was once the most common disk operating system for PCs in 80s and early 90s.
ii.
It primarily provides a command-line interface.
iii.
It loads only one application at time and supports only one user and one processor.
iv.
It recognises only 640KB of RAM.
v.
Hardware is difficult to install and configure under it.
Macintosh OS.
i.
First OS provides a truly GUI.
ii.
It has built-in network support and hardware Plug and Play (PnP) support.
iii.
It allows multi-tasking.
Windows
i.
It was designed to replace command-line interface OS (DOS) with one with GUI .
ii.
Windows 3.x
iii.
a.
Allow multiprogramming.
b.
A 16-bit without PnP support.
c.
Windows for Workgroups was added with network capabilities.
Windows NT
a.
A 32-bit OS with 2 versions (Win NT server and Win NT workstation).
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iv.
v.
vi.
vii.
b.
Win NT server functions as an OS for file and print servers.
c.
It also offers security features for authenticating users and control their access to network resources.
Windows 9x (Win 95, Win 98)
a.
A 32-bit OS that includes the older 16-bit code – thus can run programs for DOS and Win 31.
b.
It offered multitasking with an improved GUI.
c.
It offered Plug and Play standard for connecting new hardware.
Windows 2000
a.
It combines Win NT and Win 98.
b.
4 versions: Professional, Server Standard Ed., Advanced Server and Data Centre Server.
Windows XP
a.
It combines its consumer-grade and enterprise OS into one product family.
b.
2 version: Professional and Home.
c.
Upgraded features: Data media support and Advanced communication (Universal Plug and Play).
Windows 2003
a.

The .NET Enterprise Server suite consists different servers: file and print server, web server, mail server,
streaming media server.
Embedded OS
i.
It is built into the circuitry of an electronic device.
ii.
They are found in devices such as PDA (personal data assistant) and mobile phones.
Cross-platform

A platform consists of an OS, processors with coordinating programs and hardware, e.g. Pentium IV running
Win XP.

Cross-platform refers to applications, file formats or hardware devices that can run on any platform.

Cross-platform is becoming increasingly important for frequent exchanging information using computers and
Internet.

Samples of cross-platform achievements:
i.
OS: Linux
ii.
Application: Java
iii.
File format: TIFF, PDF
iv.
Internet: HTML
v.
Communication standard: TCP/IP
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Utility Software
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Disk Defragmenter.
i.
A file may be broken into pieces when it is being stored in a disk.
ii.
Fragmentation. A large number of files are stored in sectors away from each other. It reduces disk
performance.
iii.
Disk defragmenter rearranges pieces of data so that files are stored in sector next to each other.
Data Compression Utility.
i.
It reduces the size of files by searching for and removing unused space in a file or tightly packing data of the
file together.
ii.
e.g. WinZip.
Backup Utility.
i.

It copies large groups of files from hard disk to another storage medium such as tapes or CD-R.
Disk Management Utility.
i.
Some utilities divide a hard disk into partitions.
ii.
Some utilities keep the healthy working conditions of a hard disk.
iii.
Some utilities check the surface of a hard disk for bad sectors.
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