ROCKS is an NSF (National Science Foundation) supported project to develop and maintain cluster environments so they provide cluster installs for a wide variety of platforms. It contains the usual things, like PBS, ganglia, and many others.
To install, the first thing was to add a new SATA drive to the machine. I had a 250 gig lying around so I added it to bay 2 on the mac.
Installing rocks was easy. The procedure was relatively straightforward. One problem that turned out to be a non-issue is that Rocks said it would install itself on the first drive (I thought that would overwrite the macos on the first drive, and leave the drive in bay 2 blank). As it happened, it installed on the blank disk. All is well.
On reboot, it appears all the critical elements of the system was running: ganglia, PBS, etc.