PSU CS Department
Experimental Safety Guidelines
It sounds ludicrous to be talking about safety in connection
with computing experiments, right? After all, what could
happen: no experiment you are likely to run will have any
interesting effect whatsoever on the physical world.
Of course, there's a social world. What you want to avoid
is running an important department computer out of CPU
overnight, and thus getting thwacked senseless by your own
classmates. This is what we mean by ``experimental
Thus, please follow these helpful suggestions when
conducting compute-intensive experiments:
- Please stay off the department servers. Here's a list
of machines that you may run
your experiments on.
I believe that these machines are SPARC Ultra 5s in the lab.
You may not run your experiments on
rigel.cs.pdx.edu or sirius.cs.pdx.edu.
For anything not in either of these categories, ask someone.
If possible, be seated at the console when running
experiments, in order to avoid surprise for the console
- Ask the operating system to limit your resource usage.
Make the ulimit command your friend. In
particular, ulimit -t 900 will set a CPU limit of
900 seconds (15 minutes) for all of your subsequent runs.
Please do this, as no assignment I give you should need
longer than this, and it will help avoid accidents.
- Similarly, ask the operating system to run your jobs at
lower priority. The nice command does this:
nice -15 foo runs foo at a very low priority. The
renice command will do this for a running job: see
the manual page.
- If someone asks you to cut it out, please do so: many
people are trying to share a scarce resource, and this can
be tough. Defer to the systems group on any and all issues
related to resource usage.