is there a forum somewhere wholly dedicated to cluster computing? detailing how to build one?
Clusters run programs that give the image of a single system with massive resources such as Clusterit and others. does this mean that if i take a normal java program i wrote for a typical single XP machine, will it execute using all the resources of the Cluster?
Most cluster software has to be aware of the cluster. It can't take advantage of the cluster transparently.
Are you trying to learn for learning's sake or trying to solve a specific problem? You might want to check out http://www.globus.org/ Globus is a grid, not a cluster, but perhaps it will help get you rolling.
A few years ago we needed a grid a startup and we ended up rolling our own. All of the commercial/free toolkits had way too much security overhead for our needs.
Originally posted by Ali Gilani: so how do you make a java program aware of the cluster?
and what difference is there between a Grid and a Cluster
It means you put enough logic in your program to know how to dispatch a job to the grid. Most of the grid toolkits handle that logic for you (like the Globus link). Making your Java programs grid (or cluster) aware means picking a grid (or cluster) toolkit and using it in your software.
I've always thought of a grid as a group of machines, each one running as a independant node in the grid, requiring a controller (or master node) to dispatch jobs and a cluster being more transparent, similar to your original question. I've never done much with clusters though so I may be completely wrong.