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)