CS 3733 Operating Systems

In this laboratory you will experiment with process scheduling by using a simulator which has been written as a Java applet by Dr. Steve Robbins.

To access the simulator see the online documentation.

• Experiment I:

  Hypothesis: Round robin scheduling with n processes makes each user think the machine is running at 1/n-th the speed as long as the I/O times are small.

  • Devise tests to prove or disprove the hypothesis.
  • Conduct a series of experiments to determine the effect of perceived performance as a function of I/O burst time.

• Experiment II:

  Hypothesis: Shortest-Job-First(SJF) and First-Come-First-Served (FCFS) are the same when all of the processes have exactly the same CPU burst and I/O burst. When the CPU burst times vary, SJF reduces the average waiting time when compared with FCFS.

  • Devise tests to prove or disprove the hypothesis. Explain your results.
  • Hypothesize on the influence of some other parameter (besides CPU burst variability) on the results produced by these two scheduling algorithms. Devise and run experiments to show the influence and explain the results.

You should use the logging features of the simulator to enter your hypotheses, describe the parameters that you are varying and to log the results. You should edit and print out the html log files as your report for this assignment.