1. Information Technology Software

2. SYSTEM SOFTWARE

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

4. Types of System Software Operating System Operating System Utility Program Utility Program

5. Operating System The operating system is a set of programs that controls all the hardware and application programs that make up the computer system. Without the operating system the computer cannot function.

6. Operating System Cont’d At the starting of the computer the operating system is loading from the hard disk to RAM and it remains there until the computer is turned off.

7. Examples of the Operating System MS-DOS MS-DOS Windows (95, 98, ME, 2000, XP) Windows (95, 98, ME, 2000, XP) Apple Operating System (OS9, OSX) Apple Operating System (OS9, OSX) Linux/Unix Linux/Unix

8. Functions of the Operating System Resource management Resource management File management File management Task management Task management User Interface User Interface (Home Work – Write a paragraph on each of the functions)

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

10. Types of Booting Cold Boot Cold Boot - this is starting up the computer after it has been previously powered off (turned off). Warm Boot Warm Boot - this is restarting a computer that is already powered on (turned on).

11. Utility Programs Utility program is a type of system software that allows the user to perform maintenance type tasks, which will keep your computer running at peak performance. These tasks include: Disk Defragmenter Disk Defragmenter Scan disk software Scan disk software Virus scanning utility Virus scanning utility (Homework – Write a paragraph on each)

12. Malicious Software

13. The word Malicious means to destroy. The word Malicious means to destroy. Malicious software are software that are created with the intention to destroy computers. Malicious software are software that are created with the intention to destroy computers.

14. Categories of Malicious Software Malicious software can be classified into three main categories: Viruses Viruses Worms Worms Trojan horse Trojan horse

15. Viruses Virus is a self-replicating program containing code that explicitly copies itself and can “infect” other programs by modifying them or their environment. It can spread to multiple computers through storage devices or across network.

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

17. Trojan Horse Trojan horse is a computer program which is either hidden inside another program or that masquerades as something it is not in order to trick potential users into running it. For example a program that appears to be a game or image files but in reality performs some other functions.

18. Trojan Horse cont’d A Trojan horse is similar to a virus, except that it does not replicate itself. It stays in the computer doing its damage or allowing somebody from remote site to take control of the computer.

19. END OF LESSON 3