MOSS Simulator

moss (Modern Operating Systems Simulators) is a collection of Java-based simulation programs which illustrate key concepts presented in the text Andrew S. Tanenbaum, Modern Operating System, Second Edition (Prentice-Hall, 2001). The software is designed for students and instructors using this text.

• Read the file http://siber.cankaya.edu.tr/OperatingSystems/moss/index.html index.html carefully.
• Each simulator is packaged separately and available for
  • Scheduling Simulator
  • Deadlocking Simulator
  • Memory Management Simulator
  • File System Simulator
• Study the user guide for http://siber.cankaya.edu.tr/OperatingSystems/moss/sched/user_guide.html Scheduling Simulator
• Follow the steps below for installation of the software
  1. Create a directory in which you wish to install the simulator (e.g., "moss/sched").

     $ mkdir moss
     $ cd moss
     $ mkdir sched
     $ cd sched
     

  2. Download the compressed tar archive (http://siber.cankaya.edu.tr/OperatingSystems/moss/sched/sched.tgz sched.tgz) into the directory.
  3. Expand the compressed tar archive.

     $ tar -zxvf sched.tgz
     

  4. Export the classpath

     $ export CLASSPATH=.
     

  5. To test the program, enter the following commands.

     $ java Scheduling scheduling.conf
     

     The program will simply run the simulation based on the information provided in scheduling.conf and write its output to the Summary-Results and Summary-Processes files. You should see the following output.

     Working...
     Completed.
     

  6. Hint: If you want to compile java codes as given in the manual files, you may be faced with some errors. A suggested solution is that: If there is any import statement that is used for including user-defined class, erase it. (i.e. //import Common;)

Lab work:

1. Create a configuration file in which all processes run an average of 2000 milliseconds with a standard deviation of zero, and which are blocked for input or output every 500 milliseconds. Run the simulation for 10000 milliseconds with 2 processes. Examine the two output files. Try again for 5 processes. Try again for 10 processes. Explain what's happening.
2. Consider changing the configuration parameter ``meandev'' to
   ``run_time_average''. The word ``dev'' doesn't belong here. It would be nice if this were the average amount of time a process runs before blocking for input or output instead of the total runtime.
3. Consider changing the configuration parameter ``standdev'' to
   ``run_time_stddev''. It would be nice if this were the number of standard deviations from the average time a process runs before blocking for input or output instead of the total runtime.