UMBC CMSC421 UMBC | CSEE | CMSC421 | Spring 1999 (Section 0101)

 

Homework #5

CMSC 421, Section 0101 (Spring 1999)

Assigned: 28 April 1999
Due: 5 May 1999

Late homeworks will not be accepted.

  1. Problem 10.3 from the text.
  2. Problem 10.6 from the text.
  3. Problem 11.1 from the text.
  4. Consider a Unix file system with 12 direct pointers in each inode and 4 KB file blocks.
    1. How much overhead would be needed to store index blocks for a 100 MB file, not including the inode itself? What percentage of total file size would the overhead be?
    2. On average, how many 4 KB blocks would have to be read to get a random block from the file? Again, assume the inode is already in memory and doesn't need to be read from disk. HINT: figure out how many blocks can be read for each of direct, single, double, triple indirect and compute the average from this information.
  5. Suppose we have a disk with 6000 cylinders, numbered 0 to 5999. The disk is currently serving a request at track 492, and the previous request served by the disk was at track 431. The queue of pending requests (in order of time arrival, oldest request first) is:
    301, 2001, 5197, 1984, 2102, 86, 155, 4033, 3988
    Starting from the current head position, waht is the total seek distance (in cylinders) that the disk head has to travel using each of the following disk scheduling algorithms:
    1. FCFS
    2. SSTF
    3. SCAN
    4. LOOK
    5. C-LOOK
  6. Problem 13.10 from the text.


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Last updated 28 Apr 1999 by Ethan Miller (elm@csee.umbc.edu)