Web/cgi interfaces to some of the chapter homework simulators from http://www.ostep.org/

Download: all.tar.gz

For use in courses, the interfaces require authentication and each student receives
different random problems based on their userid.  For external demonstration purposes
there is a public version of scheduler which does not use any authentication and does
not log the results for grading.

Chapter simulator interfaces currently available:

 c04 - process-run
 c07 - scheduler 
 c08 - MLFQ
 c15 - relocation
 c16 - segmentation
 c17 - malloc
 c18 - paging-linear-translate
 c20 - paging-multilevel-translate
 c22 - paging-policy
 c37 - disk
 c38 - raid
 c40 - vsfs
 c42 - fsck
 c44 - ssd
 c45 - checksum

The public version of scheduler can be run at: https://www.ece.villanova.edu/cgi/scheduler-public
Instead of files scheduler/{scheduler,scheduler-post,post.sh} it uses slightly modified files
scheduler/{scheduler-public,scheduler-public-post,post-public.sh}

Example execution flow on the server:

 scheduler (generate problem) -> scheduler-post (pre-process user submission) -> post.sh (check answers)

Students can check their results using the -check interfaces, e.g. scheduler-check

The random seed initialization for each problem should be kept secret.  In the code provided
here all secret random seeds were modified to have "123456789" prefix, but these should be
changed to be different for each problem.
 
For each simulator, sample output in examples/ shows the given problem (e.g. checksum.html),
debug with answers (checksum-debug.html), and result checking (checksum-post.html).
One example of student checking results is shown in checksum-check.txt

All of the interfaces have optional user-defined seed and "ans" arguments.  If the user specifies
a seed then the results are not logged and the user can also request the answers to be shown.
The seed is command-line argument $2, e.g. append +12345 to end of the URL query.  If a seed
is specified and $3 is not empty then the answers are shown.  fsck takes two seeds.  Examples:
 https://myserver/os/cgi/relocation?+4321
 https://myserver/os/cgi/relocation?+4321+ans
 https://myserver/os/cgi/vsfs?operation+123456
 https://myserver/os/cgi/vsfs?operation+123456+ans
 https://myserver/os/cgi/fsck?1+123+456
 https://myserver/os/cgi/fsck?1+123+456+ans

See sim-list.txt for a list of the command-line options used with the web interfaces.

The original python scripts (in python/ here, with symlinks in the other subdirs) were
obtained on May 31, 2021 from: https://github.com/remzi-arpacidusseau/ostep-homework/
To update with changes needed for the web interfaces: cd python && patch < ../DIFF

The web interfaces use /opt/bin/dash, which can be a link to /bin/dash if available,
otherwise install from: http://gondor.apana.org.au/~herbert/dash/

R. Perry, richard.perry@villanova.edu, http://fog.misty.com/perry/