Homework #3: Scheduling
CMSC 421, Section 0101 (Fall 1999)
Assigned: 12 Oct 1999
Due: 19 Oct 1999 at 2:30 PM
Late homeworks will not be accepted.
Remember: your homework must be turned in online via submit.
- Distinguish between long term and short term schedulers. What are the criteria that influence their design?
- Schedule the following processes using FCFS, non-preemptive SJF, preemptive SJF, and round-robin (5 ms quantum). For each algorithm, show the Gantt chart for the schedule and list the average waiting time for the schedule.
Process |
Arrival time (ms) |
Burst time (ms) |
P0 |
0 |
12 |
P1 |
2 |
5 |
P2 |
5 |
7 |
P3 |
7 |
15 |
P3 |
8 |
2 |
- Problem 5.5 from the text.
- Problem 5.7 from the text.
- Your measurements of a computer system show that some processes are CPU-bound (make few, if any, I/O requests), and that the remainder of the processes are I/O-bound (make many I/O requests, but use little CPU time between them).
- In which scheduling algorithms (FCFS, preemptive & non-preemptive SJF, RR, priority) are I/O-bound processes penalized? Explain.
- Propose a scheduling algorithm that gives I/O-bound processes as much CPU time as they need to complete their tasks. Your solution may not depend on users identifying I/O-bound processes (they usually don't), and should be able to handle cases where a single process alternates between I/O-bound and CPU-bound periods.
- Problem 5.10 from the text.