Dense Memory Cluster (DMC)

The DMC at the Alabama Supercomputer Center has 2216 CPU cores and 16 terabytes of distributed memory. Each compute node has a local disk (up to 1.9 terabytes of which are accessible as /tmp). Also attached to the DMC is a high performance GPFS storage cluster, which has 45 terabytes of high performance storage accessible as /scratch from each node. Home directories as well as third party applications use a separate GPFS volume and share 137 terabytes of storage.

The machine is physically configured as a cluster of 8, 16, or 20 CPU core SMP boards. Ninety-six nodes have 2.26 GHz Intel quad-core Nehalem processors and 24 gigabytes of memory. Forty nodes have 2.3 GHz AMD 8-core Opteron Magny-Cours processors and 128 gigabytes of memory. Forty nodes have 2.5 GHz Intel 10-core Xeon Ivy Bridge processors and 128 gigabytes of memory.

The DMC has 32 NVIDIA GPU (Graphic Processing Unit) chips. These are a combination of: two Tesla S1070 units (external GPUs connected in pairs to four DMC nodes), four DMC nodes configured with two Tesla M2070 cards each, and four DMC nodes configured with four Tesla K20m cards each. These multicore GPU chips are similar to those in video cards, but are installed as math coprocessors. This can give significant performance advantages for software that has been adapted to use these processors. Thus the processing capacity of the DMC cluster is:

  • Conventional processing capacity - 29.52 TFLOPs
  • Single precision GPU capacity - 74.92 TFLOPs
  • Double precision GPU capacity - 23.53 TFLOPs


How do I change my password?

  1. Type "passwd" at a prompt in your ssh session window.

  2. Type your old password at the "Old password:" prompt. Choose option 2 to enter a new password.

  3. Type your new password at the "New password:" prompt.

  4. Retype your new password at the "Re-enter new password:" prompt.

How do I login to the SGI Ultraviolet?

  1. "ssh" to

  2. Type your login ID at the "login:" prompt.

  3. Type your password at the "Password:" prompt.

  4. You should now see a Unix shell prompt " uv:~$ " (depending on which Unix shell you use).

How do I get information on commands related to "my_topic"?

  1. Type man -k at a shell prompt.

  2. Review list of commands generated by man -k to find those that seem appropriate.

  3. Type man for each command that you select.

  4. Third party software documentation is in /opt/asn/doc.

I can't remember my password. How do I get a new one?

Contact the analyst at

What math and utility routines are available on the DMC and SGI Ultraviolet?

  • Public routines in FORTRAN and C can be found at The slatec library is already installed on the DMC.
  • The Intel Math Kernel Library is on the Ultraviolet.
  • The SGI Ultraviolet SCSL library is on the Ultraviolet.
  • The AMD core Math Library is on the DMC.
  • The ATLAS library is on the DMC.

Is the supercomputer just for hard science and engineering?

No! Although chemists, engineers, and physicists currently dominate the use of the supercomputers, we also have biologists, musicians, environmental scientists, and other non-traditional users. With the growing interest in data-mining applications in a number of fields, we expect the diversity of our user community to increase.

Please contact the HPC staff at (256) 971-7448 or if you are contemplating non-traditional use of the DMC.