Operating system file system

operating system basics of file system

1. File Systems Presented by Anil Pokhrel Bsccsit 3 semester 1

2. Contents Three essential requirements for long-term information storage File Structure File Types File Access File Operations Directories 2

3. Three essential requirements for long-term information storage It must be possible to store a very large amount of information. The information must survive the termination of the process using it. Multiple processes must be able to access the information concurrently. Files are managed by the operating system; part of the operating system dealing with files is known as the file system. 3

4. 4 File Structure Three kinds of files byte sequence record sequence tree

5. File Types 5

6. File Access Sequential access read all bytes/records from the beginning cannot jump around, could rewind or back up convenient when medium was mag tape Random access bytes/records read in any order essential for data base systems read can be … move file marker (seek), then read or … read and then move file marker 6

7. 7 File Operations Create Delete Open Close Read Write Append Seek Get attributes Set Attributes Rename

8. 8 Directories Single-Level Directory Systems A single level directory system contains 4 files owned by 3 different people, A, B, and C

9. 9 Two-level Directory Systems Letters indicate owners of the directories and files

10. 10 Hierarchical Directory Systems A hierarchical directory system

11. Refernce   http://download.microsoft.com/download/9/6/D/96D0705A-003A-4CE2-B2B2-2A437635400C/MS%20vs%20%20Red%20Hat%20WP.pdf http://smallbusiness.chron.com/five-common-operating-systems-28217.html 11

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