COMP 2006J辅导、辅导Java程序课程

Operating Systems

Assignment 01: Scheduling

COMP 2006J

Autumn, 2021

1 Scheduling Simulator

Please download the scheduling simulator skeleton code from the moodle. The scheduling simulator illustrates

the behaviour of scheduling algorithms against a simulated mix of process loads. The user can specify the number

of processes, the mean and standard deviation for compute time and I/O blocking time for each process, and

the duration of the simulation. At the end of the simulation, a statistical summary is presented.

We have given the implementation of FIFO scheduling as an example of how to implement a scheduling algorithm

in the given environment. You are allowed to use any development environment you prefer. Please go through

the instructions carefully and complete the assignment.

2 Running the Simulator

• Compile the java code using the following command.

1 $ javac *. java

• The program reads a configuration file (scheduling.conf) and writes two output files (Summary-Results

and Summary-Processes).

• To run the program, enter the following in the command line.

1 $ java Scheduling scheduling . conf

• The program will display “Working...” while the simulation is working, and “Completed.” when the

simulation is complete.

• The simulator reads parameters from the configuration file (“scheduling.conf”).

2.1 The configuration file

• The configuration file (scheduling.conf) is used to specify various parameters for the simulation.

• There are a number of options which can be specified in the configuration file. These are summarized in

the table below.

Keyword Values Description

numprocess n The number of processes to create for the simulation.

meandev n The average length of time in milliseconds that a process should execute before terminating.

standdev n

The number of standard deviations from the average length of time a process should

execute before terminating.

process n

The amount of time in milliseconds that the process should execute before blocking for input

or output. There should be a separate process directive for each process specified by the

numprocess directive.

• Please go through the FIFO method carefully and try to understand how this version of FIFO algorithm

works. Specifically, give attention to the timer-counter usage in the implementation.

University College Dublin 1

Operating Systems

Assignment 01: Scheduling

COMP 2006J

Autumn, 2021

• Try to identify the design decisions taken when implementing this algorithm. I.e: assumptions, scope and

limitations.

• Change values in the configuration file and try different types of workloads. Set ‘test’ to ‘0’ when you are

experimenting.

4 Round-robin Scheduling

• Implement the round-robin scheduling algorithm in the ‘SchedulingAlgorithm.java’ file. Use the given

‘.test’ output files as references.

• Assume that the time each process stays in the blocked state is 0.

• Use the print functions in the ‘SchedulingAlgorithm.java’ file to update the ‘Summary-Processes’ file.

5 Testing

• After implementation, execute the ‘run test.py’ to check the accuracy of your algorithm. Please note that

this script is given for your convenience. It is not mandatory to use this. It is written in python and

requires a working installation of python3 to run.

• It compares your output file with a preprocessed output file, which is generated with a round-robin

scheduling algorithm.

• You can add more of your own tests if you prefer. Please add those new tests to ‘tests.txt’ file.

6 Submission

• Submit the ‘SchedulingAlgorithm.java’ file to the submission link in the moodle before the deadline.

• You will be marked against a set of test cases.

• Please keep the code clean and add comments. There will be marks for the code quality and comments.

7 Assessment

Your submission will be tested against input that we have designed. To help you get started, a file called

run test.py has been supplied. Keep the following points in mind:

• run test.py is only a sample. The actual test will contain more tests.

• Do NOT change the input/output format of the code given to you. Any change will result in your code

failing the tests.

• Do NOT output anything other than what has been asked for. If you have added any outputs for your

own convenience, you should remove/comment them before submission.

University College Dublin 2

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