Information TechnologyInformation Technology

Software Software

SYSTEM SYSTEM SOFTWARESOFTWARE

System SoftwareSystem Software

The system software manages and The system software manages and supports the resources (hardware supports the resources (hardware and application software) and and application software) and operations of the computer system.operations of the computer system.

Types of System Types of System SoftwareSoftware

Operating SystemOperating System

Utility ProgramUtility Program

Operating SystemOperating System

The operating system is a set of The operating system is a set of programs that controls all the programs that controls all the hardware and application programs hardware and application programs that make up the computer system. that make up the computer system.

Without the operating system the Without the operating system the computer cannot function.computer cannot function.

Operating System Operating System Cont’dCont’d

At the starting of the computer the At the starting of the computer the operating system is loading from operating system is loading from the hard disk to RAM and it remains the hard disk to RAM and it remains there until the computer is turned there until the computer is turned off.off.

Examples of the Examples of the Operating SystemOperating System

MS-DOSMS-DOS Windows (95, 98, ME, 2000, XP)Windows (95, 98, ME, 2000, XP) Apple Operating System (OS9, Apple Operating System (OS9,

OSX)OSX) Linux/UnixLinux/Unix

Functions of the Functions of the Operating SystemOperating System

Resource managementResource management File managementFile management Task managementTask management User InterfaceUser Interface

(Home Work – Write a paragraph on (Home Work – Write a paragraph on each of the functions)each of the functions)

Booting Booting

Booting refers to the process of Booting refers to the process of starting (or restarting) the starting (or restarting) the computer, which includes checking computer, which includes checking that the computer is working that the computer is working properly and loading the operating properly and loading the operating system from the hard disk to RAM.system from the hard disk to RAM.

Types of BootingTypes of Booting

Cold Boot Cold Boot - this is starting up the computer - this is starting up the computer

after it has been previously powered off after it has been previously powered off (turned off).(turned off).

Warm Boot Warm Boot - this is restarting a computer that - this is restarting a computer that

is already powered on (turned on).is already powered on (turned on).

Utility ProgramsUtility Programs

Utility program is a type of system Utility program is a type of system software that allows the user to perform software that allows the user to perform maintenance type tasks, which will keep maintenance type tasks, which will keep your computer running at peak your computer running at peak performance. These tasks include:performance. These tasks include:Disk DefragmenterDisk DefragmenterScan disk softwareScan disk softwareVirus scanning utility Virus scanning utility

(Homework – Write a paragraph on (Homework – Write a paragraph on each)each)

Malicious Malicious SoftwareSoftware

Malicious SoftwareMalicious Software

The word Malicious means to The word Malicious means to destroy.destroy.

Malicious software are software Malicious software are software that are created with the that are created with the intention to destroy computers. intention to destroy computers.

Categories of Categories of Malicious SoftwareMalicious Software

Malicious software can be classified Malicious software can be classified into three main categories:into three main categories:Viruses Viruses Worms Worms Trojan horseTrojan horse

VirusesViruses

VirusVirus is a self-replicating program is a self-replicating program containing code that explicitly copies containing code that explicitly copies itself and can “infect” other programs itself and can “infect” other programs by modifying them or their by modifying them or their environment. environment.

It can spread to multiple computers It can spread to multiple computers through storage devices or across through storage devices or across network.network.

Worms Worms

A computer A computer WormWorm is a self-replicating is a self-replicating computer program, similar to a computer program, similar to a computer virus. computer virus.

A virus attaches itself to and become A virus attaches itself to and become part of another executable program; part of another executable program; however, a worm is self-contained however, a worm is self-contained and does not need to be part of and does not need to be part of another program to propagate itself.another program to propagate itself.

Trojan HorseTrojan Horse

Trojan horseTrojan horse is a computer program is a computer program which is either hidden inside another which is either hidden inside another program or that masquerades as program or that masquerades as something it is not in order to trick something it is not in order to trick potential users into running it. potential users into running it.

For example a program that appears For example a program that appears to be a game or image files but in to be a game or image files but in reality performs some other reality performs some other functions.functions.

Trojan Horse cont’dTrojan Horse cont’d

A Trojan horse is similar to a virus, A Trojan horse is similar to a virus, except that it does not replicate except that it does not replicate itself.itself.

It stays in the computer doing its It stays in the computer doing its damage or allowing somebody from damage or allowing somebody from remote site to take control of the remote site to take control of the computer.computer.

END OF LESSON 3END OF LESSON 3