Computing guidelines
Physics Department Computing Facility
Wean Hall 6332, Phone 412-268-4382
Manager: Al Brunk, 412-268-2736
abrunk@andrew.cmu.edu
hardware software guidelines FAQ
The Physics Department maintains this cluster of computers for research-oriented and
general purpose computing by physics graduate students, faculty, staff and visitors. We
ask users to note these guidelines governing use of the cluster. The purpose of these
suggestions is to enhance the utility of the cluster for all users and to ensure equitable
sharing of the resources. Users must also follow the CMU computing policy.
Cleanliness and consideration
Food and drink are prohibited. When talking, please respect others working nearby. Log
off when not actively using computer and clean up your work area when you are done. Feel
free to clean off keyboards, monitors and mice when they need it. Place uncollected
printer output in the racks closest to the printer. Make use of the paper recycling and
waste baskets.
Disk space
A certain fraction of the disk space is available for users to store their
own files and programs. This disk space is NOT backed up, so use at your own
risk. USB drives and CD
writers are available for you to perform your own backup on
XP
and Linux. A separate guide to using removable media on Linux is available. On unix/Linux systems
ample local storage is available in /usr/user. In contrast, /tmp is kept nearly empty at
all times for emergency storage space. Files in /tmp will be subject to
removal without warning. For storage needs in the range of 10-75 MB your best
solution is probably a "project volume" on the Andrew system. This space is
backed up and automatically shared on all Andrew system computers. On XP systems user space is available on the
D:\
drive. On Macintosh computers make yourself a folder in User. Users taking large amounts
of disk space on any system may be asked to cut back to make room for others.
CPU time
Linux systems support remote login and running of background jobs. For this reason you
should NEVER reboot a linux computer in the public cluster. To ensure that background jobs
do not interfere with interactive computer use, and to ensure equitable sharing of CPU
time, we ask background job users to follow these rules:
- Nice the job at level 15. A typical syntax to follow is
nice +15 program_name < input_file > output_file &
- No more than one background job/person/CPU.
- No more than two background jobs/computer (total, among all users) on a single processor
computer or three jobs/computer on a dual processor computer.
To check the load on a computer use one of the commands w or ps
aux or top. To check the load on another computer (without
having to log in) use the command
rsh host.phys.cmu.edu w.
Note that you are allowed up to two simultaneous jobs on a dual processor
computer. This equals the processing power you can get using parallel processing
(with MPI or open MP). Please do
not use parallel processing unless you have proven through careful
benchmarking that your program attains high parallel efficiency.
Printing
Printing is presently provided free of charge. Please do not abuse this privilege, or a
printing charge may be imposed in the future. Use hpcolor for color
printing only. Use duplex (two sided) printing on Osage to conserve paper. Be
certain to use the correct transparency type in laser printers. Sign out transparencies on
the sheet provided. Bring paper from stockroom when supplies run low in the cluster.
Maintenance
The people responsible for maintaining the computer cluster rely on individual users to
report problems and offer ideas for improvements. Please contact the cluster manager: Al
Brunk, 412-268-2736, abrunk@andrew.cmu.edu.
Thank you for taking an active interest in maintaining this facility.
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