The morning tutorials and exercises were all about accessing the supercomputer. Southern Man has been through this drill a few times now and after completing the exercise was able to circulate around and help some of the new users.

The supercomputer is, like most, a fairly vanilla cluster of fairly vanilla PCs that are not unlike what you may have in your lap or on your desk. The "vanilla" part is actually important, as it ensures that any problems the system has are well known and easily solved. The cases are different - they are standard "pizza box" servers so that they fit nicely in racks - but with ordinary processors and memory and cheap hard drives.

A rack of pizza boxes.

The "supercomputer" part is that there are a lot of them and they communicate on two distinct neworks - one with high bandwidth (to move data) and one with low latency (for communications). It runs RedHat Enterprise Linux (which has broad support) and the LFS job scheduler.

And it sits under about a hundred tons of air conditioning. It was about 45^o in the "cold tunnel" last night. Photo by OSCER.

Programming is strictly old school: a Linux command prompt, the vi editor, and the C programming language. Today we spent a lot of time learning (or in Southern Man's case relearning) MPI, a set of routines for parallel processing. After a few introductory programs we set to work computing the value of π from basic geometry.

So Southern Man solved this familiar problem using one core, then on many cores (with one trapezoid per core), and then on many cores with many trapezoids per core...

Southern Man hates vi.

More computing cycles were consumed to bring you this result (which used a grid size of a million) than the USA used in the 1960s to put a man on the moon.

That actually took until dinner, and afterwards.

They feed us dinner in a nice dining room in the Student Union. The fellow in the center is the designer of the LittleFe mini-supercomputer.

These three grad students (who Southern Man first met at SC11) are doing most of the work.

So the first full day of the workshop was fun and productive. Onward to tomorrow!

3 Comments:

At Monday, July 30, 2012, Anonymous said...: Is your work fun?
At Monday, July 30, 2012, Anonymous said...: Is Linux the future? Or is something else on the horizon that we mere users do not know about?
At Tuesday, July 31, 2012, Southern Man said...: My job is interesting, just the right degree of challenging, lets me travel from time to time, and pays well. I'm lucky to be doing what I am.

Linux has been around for a while. Linux (and UNIX) pretty much run all of the big computers (like your bank, and the Internet) so you use it (without knowing it) every day. It's cheap (even free) but a challenge to learn.