How do I use X-window based software on the DMC?

The following commands can be used to setup a X-window connection to the DMC from a machine running UNIX X-windows. The commands might be slightly different from a Macintosh or PC with an X-window emulator.

  1. ssh -Y user_id@dmc.asc.edu (where user_id is your login)

  2. Type the command

  3. See the HPC documentation website for additional information on how to install and use X-Windows

How do I find out how much memory and CPU time my job used?

After the job has completed, type the command “jobinfo -j JOBNUMBER”.

What do I do if my disk quota is exceeded?

All user accounts on the DMC have disk quotas, which determine how much information can be stored in the home directory and it's subdirectories. By default, this quota is 20 GB. Users can see their disk quota by typing "quota" or "usage".

Please note that it has always been the policy that disk space on the supercomputers is for work in progress, not permanent backup or archival. Completed work should be transferred to a campus facility for permanent storage.

While a calculation is in progress, the /scratch file system provides a large amount of temporary disk space. The amount of space that can be used on /scratch is limited by the choice of job queue. To see the queue disk limits, type "qlimits". Any files created on /scratch must be removed within one week after the calculation completes. Files left on /scratch more than a week are automatically deleted.

If the nature of your work is such that you must have a larger home directory quota, you can request a larger quota. Users can request up to 1 TB quotas at no charge. Send an email with your request and a brief justification to the HPC technical support staff at hpc@asc.edu

For quotas over 1 TB, please contact us to obtain a quote to purchase additional resources. To obtain a formal written quote for disk space, contact Nichole Gipson, ASA Client Services Assistant and E-rate Coordinator, at ngipson@asc.edu or 334-242-0175.

What is the batch system and how is it used?

Unlike PC's, these platforms are not designed for interactive work. Therefore, jobs that need running are submitted to a batch system for processing. The system handles multiple requests and schedules each job based on which batch queue was requested. To see a list of available queues, type qlimits at the prompt.

  1. To utilize the batch system, contact the analyst for help at hpc@asc.edu.

  2. If you are using an application package, run scripts are available which automatically submit your job for you. These are usually located in /apps/scripts. All you do is run the script and answer the questions.

  3. If you are compiling your own code, the analyst has scripts designed to compile, execute and scp your code anywhere you desire.

  4. If you feel comfortable using Unix scripts, prepare a simple script that runs your executable and submit it to the appropriate queue with the run_script command as follows

    run_script <scriptname>

How can I get help with my code?

Contact the analyst at hpc@asc.edu

I am on sabatical at another institution and cannot open a ssh session to the DMC. What is wrong?

The Supercomputers are only accessible from university campuses in Alabama and the home providers in those cities.

  1. First ssh to a machine at your home institution, then ssh to the DMC.

  2. Contact the analyst at hpc@asc.edu

How do I get an account on the supercomputer?

There is an annual request for supercomputer accounts, via a web form. This is free for academic use in the state of Alabama, with commercial rates available.

To get an account on the Ultraviolet, please click here to request an HPC account.

After filling out the form, click "Submit Grant Application". This will generate a second page summarizing the information you entered. This second page must be printed, signed and faxed to (256) 971-7491.

You will receive an email with your account password and information on accessing the SGI Ultraviolet within a couple days.

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