1. IT320 OPERATING SYSTEM CONCEPTS Unit 7: File Management July 2011 Kaplan University 1

2. Upcoming Topics Kaplan University 2  Unit 7: File Management  Unit 8: Computer Security Risks & Data Protection  Unit 9: Distributing Computing and Networking  Unit 10: Final Project  Due Tuesday, July 26 by 11:59 ET

3. Unit 7 Overview Kaplan University 3  Readings  Discussion Questions  Review Unit 7 Assignment  Lecture on File Management  Preview of Final Project

4. Unit 7: Reading & Assignments Kaplan University 4  Textbook Reading  Chapter 12 – File Management  Start with chapter summary first!  Web Articles Reading  2 Discussion Questions  3 page essay based on File Management (due Tuesday)

5. Unit 7: Discussion Questions Kaplan University 5  DQ1: NTFS vs FAT o Visit the two links below to learn more about NTFS and FAT. Feel free to review other publications to learn about the two file systems, including their highlights, applications, strengths, and weaknesses. DQ2: Directory Structure – Linux vs Windows o In addition to your book reading about the Linux file system, take a look at this article about the Linux file system anatomy. Compare Linux to the way Windows deals with files and compare the two directory structures. o http://www.ibm.com/developerworks/linux/library/l-linux- filesystem/

6. Unit 7: Assignment Kaplan University 6 1.Select one operating system you are familiar with. Write a one-page summary that lists and explains the utilities provided by the operating system to manage the file system.  How often should these utilities be executed?  How is file security implemented? 2.Write a one-page summary comparing FAT/FAT32 and NTFS file systems in a Windows operating system. What are the benefits of each? Why would one file system used over the other? 3.Write a one-page summary comparing the Unix, Linux, and Windows file systems.

7. Unit 7: File Management Kaplan University 7  Your paper should include at least 3 pages of content (including required content, intro & conclusion)  Note that your paper will be longer than 3 pages as it will have a title page and a reference page in addition to the actual content pages required.  Be to include an introduction and conclusion (5 pts each)  Use APA format

8. Unit 7: Grading Rubric Kaplan University 8

9. Chapter 12 – File Management 9 Kaplan University

10. File Management System  File Management System  Set of system software that provides services to users and applications in the user the files  Minimum set of requirements: Users should be able to create, delete, read, write and modify files Users may have controlled access to other users’ files Users may control types of access to files Users should be able to move data between files Users should be able to back up and recover files Users should be able access files by name rather than numbers Kaplan University 10

11. File System Architecture  Figure 12.1 (Textbook – p. 555)  Top Level – Access method  Standard interface between applications and the files systems and device that hold data  2 nd Level – Logical I/O  Enables users and applications to access records  3 rd Level – Basic I/0 Supervisor  Responsible for all file I/O initiation and termination Kaplan University 11

12. File System Architecture  4 th Level – Basic File System  Also known as Physical I/O Level  Primary interface with the environment outisde the computer system  Deals with blocks of data exchanged on secondary storage device  Can you name an example of secondary storage?  5 th Level – Device Drivers  Communicate directly with peripheral devices or their controllers or channels Kaplan University 12

13. File Organization & Access  Important Criteria:  Short access time  Ease of update  Economy of storage  Simple maintenance  Reliability  File Organization Types  Pile  Sequential File  Indexed Sequential File  Indexed File  Direct (hashed) file  See pp. 558-562 13 Kaplan University

14. File Directory  The Directory contains information about the files, including attributes, location, & ownership.  Figure 12.2 (p. 563) show information elements  Basic Information file name, file type, file organization  Address Information volume, starting address, size used  Access Control Information owner, access information, permitted actions  Usage Information date created, indentity, last read, last modified 14

15. File Sharing  Access rights include  None  Knowledge  Execution  Reading  Appending  Updating  Changing Protection  Deletion Kaplan University 15

16. Windows File System  New Technology File System (NTFS)  Flexible and powerful file system build on simple file system model  Recoverability  Security  Large disks and large files (more efficient than FAT)  Multiple data streams  Journaling  Compression & Encryption Kaplan University 16

17. NTFS Volume & File Structure  Disk Storage Concepts  Sector Smallest physical storage unit on disk, typically 512 bytes  Cluster One or more contiguous sectors (next to each other)  Volume A logical partition on a disk, consisting of one or more clusters used by a file system to allocate space Kaplan University 17

18. File Allocation Table (FAT)  File Allocation Table (FAT)  Stores position of each file in a directory tree  Directories are not files  Need a mapping function to dynamically construct files corresponding to the directories  What issues can you see with FAT vs NTFS? Kaplan University 18

19. Linux Virtual File System  Virtual File System (VFS)  Single, uniform file system interface to user processes  Assumes files are objects in computer’s storage memory  Files have symbolic names to allow unique ID  Diagram of Linux File system Figure 12.17 (p. 588) Kaplan University 19

20. Comparing Windows & Linux  Nice comparison chart (p. 592)  Windows File System  NTFS  Implemented as a device driver (can be layered)  Depends on I/O System & Cache manager  Directories, files, & file system metadata are all represented as files by NTFS  Relies on unified caching by the CACHE manager Kaplan University 20

21. Comparing Windows & Linux  Linux File System  Most common are Ext2, Ext3, JFS (Journaling file system)  Implemented using the Virtual File System (VFS) technique (created by Sun Microsystems)  File Systems are plug-ins for VFS model  Used a page cache, keeps copies of recently used pages in memory  VFS treats directory entries and file metadata separate from actual files Kaplan University 21

22. Operating System Utilities  Definition – “system software designed to help analyze, configure, optimize, and maintain the computer” (Wikipedia, 2010).  Different than application software  Typically highly specialized  http://en.wikipedia.org/wiki/Utility_software  Can you name 2 examples of operating system utilities? Kaplan University 22

23. OS Utility Categories  Disk Storage  Defragmenters  Disk Checkers  Disk Cleaners  Disk Partitions  Backup  Disk Compression  File Managers  Archive  System Profilers  Anti-virus  Cryptographic  Registry Cleaners  Network Utilities 23 Kaplan University

24. Preview – Final Project 24 Kaplan University

25. Final Project Kaplan University 25  Due Tuesday, July 26  No late assignments accepted!!!  Final Project is worth 200 points  Write a 5 – 10 page essay explaining how a mainstream modern (Linux or Windows) Operating System is designed to integrate all components of the operating system.  At least 3 outside references  Include topics on the next page

26. Final Project Kaplan University 26  The following list of topics is a starting point for your essay. You may include other topics if you feel they are important.  Processes and threads  Memory management  Scheduling (Including deadlock prevention)  File Management  Input and Output devices  Security issues (Discuss current malware threats & prevention techniques)  Data protection (RAID & Clusters)

27.  Paper Length (5 pages), APA Style10 pts  Content of paper shows understanding20 pts  Introduction & Conclusion included10 pts  Processes & Threads20 pts  Deadlock (avoidance, prevention, detection)20 pts  I/O for chosen OS20 pts  Scheduling20 pts  Data Protection (RAID, backups)20 pts  File Management20 pts  Security Techniques & Defenses20 pts  Security Threats20 pts Kaplan University 27 Final Project – Grading Rubric

28. Any Questions? Kaplan University 28  Pam Van Hook Email: pvanhook@kaplan.edu