Homework 4
cs550 Operating Systems
5 points
Due Wednesday, Nov. 12, 2014 at midnight

1. (1.5 points) Draw Gantt charts for the following scheduling situations, you may assume that all processes arrive at the same approximate time and will enter the CPU in the order given unless otherwise specified.

a) Round Robin scheduling with five processes with the following burst times P1 - 124ns, P2 - 30ns, P3 - 90ns, P4 - 216ns, P5 - 104ns.  You may assume a time slice of 30ns.

b) Shortest Job First with five processes with the following burst times P1 - 127ns, P2 - 36ns, P3 - 98ns, P4 - 213ns, P5 - 140ns.

c) Shortest Remaining Time Next with five processes with the following burst times P1 - 177ns, P2 - 28ns, P3 - 89ns, P4 - 120ns, P5 - 108ns, and a sixth process, P6 - 87ns, arriving at time 200ns.

2. (1.5 points) Using the banker's algorithm, determine if a safe state can be achieved. Assume each process can complete its work once it receives its maximum claim.

a) There are four resource types with the total number of system resources expressed as the tuple (2, 3, 2, 2).  There are three processes with current allocations of (0, 1, 0, 1), (1, 1, 0, 0), and (0, 0, 1, 0).  The maximum claim of each process is (1, 1, 0, 1), (1, 2, 0, 0), and (1, 2, 2, 1). 

b) There are three resource types with the total number of system resources expressed as the tuple (4, 4, 2).  There are three processes with current allocations of (0, 0, 0), (1, 1, 0), and (2, 0, 0).  The maximum claim of each process is (2, 0, 1), (3, 2, 0), and (3, 0, 1).

c) There are four resource types with the total number of system resources expressed as the tuple (5, 6, 7, 2).  There are four processes with current allocations of (1, 2, 0, 1), (1, 1, 4, 0), (1, 1, 0, 0), and (0, 0, 2, 0).  The maximum claim of each process is (2, 2, 2, 2), (2, 3, 4, 1), (1, 3, 0, 0), and (1, 3, 2, 1).

3. (2 points) Read about a modern file system (one that is currently used and includes non-empty information on all of the items below) not discussed in class and discuss its attributes.  Include the following information:
    -Name of the file system
    -Support for journaling/transaction logging
    -Maximum volume size
    -Maximum file size
    -Description of file permissions
    -Discussion of directory structure
    -Description of why this file system is useful
    -Reference for your information (not Wikipedia)