1. Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill Technology Education Introduction to Computer Administration Introduction to Computer Administration

2. Operating System Basics Operating System Operating System Objectives Layers of Computer Systems Services Provided by the Operating System Functions of Operating Systems Types of Operating Systems Enhancing an OS

3. Operating System A program that controls the execution of application programs An interface between applications and hardware

4. Operating System Objectives Convenience –Makes the computer more convenient to use Efficiency –Allows computer system resources to be used in an efficient manner Ability to evolve –Permit effective development, testing, and introduction of new system functions without interfering with service

5. Layers of Computer System

6. Services Provided by the Operating System Program development –Editors and debuggers Program execution Access to I/O devices Controlled access to files System access

7. Services Provided by the Operating System Error detection and response –internal and external hardware errors memory error device failure –software errors arithmetic overflow access forbidden memory locations –operating system cannot grant request of application

8. Services Provided by the Operating System Accounting –collect statistics –monitor performance –used to anticipate future enhancements –used for billing users

9. Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill Technology Education Operating System Basics Ref Book: Chapter # 7: Introduction to Computers, Peter Norton McGraw-Hill. www.mhhe.com/peternorton

10. 7A-10 Functions of Operating Systems Provide a user interface Run programs Manage hardware devices Organized file storage

11. Providing a User Interface User interface –How a user interacts with a computer –Require different skill sets

12. Providing a User Interface Graphical user interface (GUI) –Most common interface Windows, OS X, Gnome, KDE –Uses a mouse to control objects –Uses a desktop metaphor –Shortcuts open programs or documents –Open documents have additional objects –Task switching –Dialog boxes allow directed input

13. Graphical User Interface

14. Providing a User Interface Command line interfaces –Older interface DOS, Linux, UNIX –User types commands at a prompt –User must remember all commands –Included in all GUIs

15. Command Line Interface

16. Running Programs Many different applications supported System call –Provides consistent access to OS features Share information between programs –Copy and paste –Object Linking and Embedding

17. Managing Hardware Programs need to access hardware Interrupts –CPU is stopped –Hardware device is accessed Device drivers control the hardware

18. Organizing Files and Folders Organized storage Long file names Folders can be created and nested All storage devices work consistently

19. Types of Operating Systems Real-time operating system –Very fast small OS –Built into a device –Respond quickly to user input –MP3 players, Medical devices

20. Types of Operating Systems Single user/Single tasking OS –One user works on the system –Performs one task at a time –MS-DOS and Palm OS –Take up little space on disk –Run on inexpensive computers

21. Single Tasking Operating System cannot be able to take control back from the running process/task/application In case if a process call an I/O Instruction then Processor must wait for I/O instruction to complete before preceding

22. Types of Operating Systems Single user/Multitasking OS –User performs many tasks at once –Most common form of OS –Windows XP and OS X –Require expensive computers –Tend to be complex

23. Multitasking Operating System can take control back from the running process and can give it to other. When one job needs to wait for I/O, the processor can switch to the other job

24. Types of Operating Systems Multi user/Multitasking OS –Many users connect to one computer –Each user has a unique session –UNIX, Linux, and VMS –Maintenance can be easy –Requires a powerful computer

25. Multi user/Multi tasking OS

26. Enhancing an OS Utilities –Provide services not included with OS –Goes beyond the four functions –Firewall, anti-virus and compression –Prices vary

27. Enhancing an OS Backup software –Archives files onto removable media –Ensures data integrity –Most OS include a backup package –Many third party packages exist

28. Backup Software

29. Enhancing an OS Anti-virus software –Crucial utility –Finds, blocks and removes viruses –Must be updated regularly –McAfee and Norton Anti-Virus

30. Enhancing an OS Firewall –Crucial utility –Protects your computer from intruders –Makes computer invisible to hackers –Zone Labs is a home firewall –Cisco sells hardware firewalls

31. Enhancing an OS Intrusion detection –Often part of a firewall package –Announces attempts to breach security –Snort is a Linux based package

32. Enhancing an OS Screen savers –Crucial utility for command line systems Prevents burn in –Merely fun for GUI systems –Screen saver decorates idle screens

33. Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill Technology Education Reference Book: Introduction to Computers, Peter Norton McGraw-Hill. www.mhhe.com/peternorton Introduction to Computers, Peter Norton McGraw-Hill. www.mhhe.com/peternorton