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CS 5631 Study Questions and Homework

File systems (Chapters 11-14)

Homework 6

Homework (5 points) due Tuesday, April 6, 2004.

For Homework 6, turn in your answers for the following study questions: 3 (1 point), 5 (2 points), 9 (1 point), and 12 (1 point).

Homework 7

Homework (6 points) due Tuesday, April 13, 2004.

For Homework 7, turn in your answers for the following study questions: 7 (1 point), 13 (1 point), 14 (2 points), and 16 (1 point).

Study questions

  1. Describe some kinds of information about a file that an operating system might need to maintain.

  2. Why does an operating system maintain a global table of open files?

  3. Good operating systems support both sequential and direct access. Why is support needed for both?

  4. What is the difference between hard and symbolic links from the users point of view?

  5. What are are three types of allocation methods for file storage on disk? Which is used in MS-DOS? Which is used in UNIX?

  6. Describe the block cache structures of a UNIX operating system.

  7. What is logical (or soft) formatting?

  8. What is the purpose of a boot block?

  9. In the UNIX operating system, an inode is used to store information about a file. It does not contain the file name. Where is the file name stored? Explain why that is.

  10. In the UNIX operating system, when does the storage allocated to a file get freed up?

  11. What is the difference between the implementations of hard and symbolic links.

  12. A UNIX system may have numerous hard disks, yet the file system appears to be a single heirarchy to the user. How is this accomplished?

  13. In UNIX, what is the difference between a file and a stream?

  14. A disk drive has 2000 cylinders, numbered 0 to 1999. The drive is currently servicing a request at cylinder 783, with the previous request at cylinder 707. The queue of pending requests, in FIFO order, is 
        75, 678, 1623, 247, 248, 1529, 182.
    What distance, in tracks, must the disk read-write arm move in order to service the requests for each of the following disk scheduling algorithms?
    1. FCFS
    2. SSTF
    3. SCAN
    4. LOOK
    5. C-SCAN
    6. C-LOOK
  15. What is the difference between a hard disk and CD/DVD data organization? How does rotation of the disk differ?

  16. What is spooling? What device characteristic makes spooling necessary?

  17. Why do UNIX (and other OS) kernel I/O structures use pointers to functions such as read() and write()?

  18. In OS networking software what purpose do STREAMS modules serve?

  19. What are the primary advantages of RAID systems?

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