Supercomputer Applications
UNIT #5   -   Ray Tracing and the Linux Cluster

What is POV-Ray

 Example Ray Traced Image POV-Ray is a free raytracing program developed by a number of contributors on the web. It allows people to define complex scenes mathematically, and then calculates what that image would look like with almost photographic type realism. There are many resources on the web related to POV-Ray, but the following are good places to start.

Using the Linux Cluster

In this unit we will be using the TJHSST Linux Cluster in order to create a number of different frames in an animation. Rather than being generated sequentially, it will be faster to have several processors working on different ray traced images at the same time.

The cluster is running MOSIX, a software product developed in Israel that allows a group of Linux computers to manage multiple tasks. Parallel processing on the cluster is slightly from similar programs run under PVM because the operating system handles the distribution of tasks rather than the programmer. If some of the processors are already much busier than the others, MOSIX will not give them extra work to do. Making all of the processors share the work load is called "Load Balancing", a great concept in theory but unfortunately not the way group work actually happens in most school situations.

For MOSIX to work well, there are some design considerations that must be followed in order to have the tasks migrate properly to the different nodes of the cluster. The general approach begins with an initial program started on one of the cluster nodes, but that program spawns multiple copies of itself using the UNIX command fork. MOSIX then balances the load among the various nodes in the cluster by moving those programs to nodes that are relatively free.

Assignments - UNIT #5