1. CHAPTER 2: OPERATING SYSTEMS (Part 2) COMPUTER SKILLS

2. ■ Objectives: – To learn about mobile operating systems. – To learn about date security and computer ethics. – To learn about computer viruses. ■ Outline: – Mobile Operating Systems – Data security – Computer ethics – viruses – Practical 2: Use windows defender in Windows Computer skills Operating Systems2

3. 3. Mobile Operating Systems ■ Features of Mobile Operating Systems: -Supports SMS and MMS messages. -Supports Web browsing -Supports touch screens and touch input -Supports wired and wireless internet communications. ■ The most popular Mobile Operating Systems: -Android OS -Apple IOS -Windows Phone Computer skills Operating Systems3

4. 3.1. Android Operating System ■ Android literally means a robot that looks and acts like a human being. ■ It is based on the Linux kernel and currently developed by Google. ■ Android is designed primarily for touchscreen mobile devices such as smartphones and tablet computers. Computer skills Operating Systems4

5. 3.2. Apple IOS ■ Apple IOS is the oldest mobile operating system. ■ It is developed by Apple. ■ One of the shortcomings of Apple IOS is that all releases of the system are almost identical and some IOS applications have been breached by hackers. Computer skills Operating Systems5

6. 3.3. Windows Phone ■ Windows phone is the most recent mobile operating system. ■ It is developed by Microsoft corp. ■ Windows phone features a new user interface derived from Metro design language. Computer skills Operating Systems6

7. 4. Data Security ■ With the spread of the internet and the huge data exchange over it, data protection has become a serious concern especially with the increasing security threats. ■ Threats can lead to: -Unauthorized access -Destruction -Disclosure -Modification of information -Denial of service Computer skills Operating Systems7

8. 4.1. Keep the systems secure ■ Computer users should do the following to keep their systems secure: -Install anti virus software and update it regularly. -Never open email attachments coming from unknown senders, nor open suspicious links. Viruses and malware can be attached with emails. -Enable pop-up blocker on your internet explorer. -Never try to access blocked websites by bypassing filtering systems. -Update your computer system (Windows) regularly. -Use a firewall. -Computer systems can be protected using a user name and a password. -Create backup copies of your data and software programs. -Identify secure website. Computer skills Operating Systems8

9. 4.2. Computer Ethics ■ Computer ethics is a set of moral principles that regulate the use of computers. ■ Software copyright issues: -Copyright laws prohibit copying or distributing copyrighted software. -Copying or distributing copyrighted software is a law violation. -When a user pay a software, he got a “User License” with a “Production Key” to get free future updates. -Freeware is a software that is made for free, but is copyrighted by law -Shareware is a software that can be used on as a trial version, often it has limited functionality or may only be used for a limited time before paying and registration. Computer skills Operating Systems9

10. 5. Computer Viruses ■ A computer virus is a malware program that, when executed, replicates by inserting copies of itself into other computer programs, data files or the boot sector of the hard drive. ■ Virus Replication Mechanisms: -The replication mechanism -The protection mechanism -The trigger mechanism -The payload mechanism Computer skills Operating Systems10

11. 5.1. Virus types ■ Boot Sector Viruses: during start-up, the virus is loaded to the memory. ■ File Infector Viruses: infects executable programs and spreads quickly via CDs and internet. ■ Macro Viruses: infects some applications like Microsoft Word and performs a sequence of actions when that application is started. Computer skills Operating Systems11

12. 5.2. Malware Types ■ Viruses: is a computer program that is intended to damage software systems or hardware components by attaching itself with other files. ■ Worms: like viruses, but they spread to other computers in a network without attaching themselves with other files. It consumes most of the system memory or network bandwidth. ■ Trojan Horses: they appear as useful software but actually cause damage once installed or runs on a computer. It comes as a part of an executable file, and doesn’t replicate itself like viruses and worms. ■ Spyware: it collects and sends private information from the infected computer to a third party like websites that visited by the user. Computer skills Operating Systems12

13. 5.3. How Viruses Infect Computers ■ Open an infected file or email attachment. ■ Download untrusted files from unknown sources or suspicious websites. Computer skills Operating Systems13

14. 5.4. How to Detect Viruses By observing one of the following: ■ Appearance of error messages in different applications. ■ Appearance of messages that say there is insufficient space (in Hard Disk) to save work. ■ Loss of some executable files ■ Slowdown in the system performance or failure to run applications. ■ Starting applications takes longer than usual. ■ Appearance of messages that say there is insufficient space (in RAM) to run programs. ■ Some file sizes get larger than normal. ■ Appearance of pop-up messages from unknown sources. ■ Appearance of messages about hardware compatibility issues. Computer skills Operating Systems14

15. 5.5. Antivirus Software ■ An Antivirus software usually takes two steps to remove viruses and malwares: First, it scans the computer to detect viruses and malwares. Second, it removes the viruses and malwares when found. Computer skills Operating Systems15

16. 5.6. Protective Procedures to Avoid Virus Infection ■ Create backup copies of your software and files. ■ Avoid the use of pirated software programs or programs from untrusted sources. ■ Follow-up the processes that try to modify applications. ■ Make sure that staff members are aware of the protective procedures against viruses and malwares and avoid installing software brought from outside the work environment unless they are scanned for security. ■ Scan new software on a separate computer (not connected to a network) so that infection will not reach other computers. Computer skills Operating Systems16

17. 5.7. Windows Defender ■ It is the first line of defense against spyware and other unwanted SW. ■ It protects the computer system using two defense strategies: -Windows Defender real time spyware protection runs in the background and alerts you when spyware and other potentially unwanted SW attempts to install itself or run on your computer. -Providing real time scanning option. ■ Windows Defender is installed by default on Windows 8.1 Computer skills Operating Systems17

18. Practical 2: Using Windows Defender ■ To learn how to use Windows Defender, follow the following steps: -Go to search box, as we learned before, and type “Windows Defender”, open it, the program will appear with its multiple options. -To update the definition of viruses and malware, select the “update” tab on the program’s main window. Then select the “update” command, so the virus definition update process will start. -To start scanning for viruses and malware, select the “Home” tab on the program’s main window, then select one of the scanning options (described in next slide) and then click on “Scan now”. Computer skills Operating Systems18

19. Practical 2: Windows Defender Scanning Options ■ Quick Scan: it quickly scans the main locations that are likely to be infected by viruses and malware. ■ Full Scan: it scans all the files and folders on the hard disk of the computer. It also scans the programs running at the time. However, This might lead to a slowdown in the system until the scan is finished. ■ Custom: it scans selected files, folders or storage media. Computer skills Operating Systems19

20. References ■ The course book, Computer skills, pages: 69-129 Computer skills Operating Systems20