
cpudisk represents the simulation of the following network composed
of 1 CPU and 4 disks:


    CPU -----------------> Disk 1 ---->|
    ^           |                      |
    |           |--------> Disk 2 ---->|
    |           |                      |
    |           |--------> Disk 3 ---->|
    |           |                      |
    |           |--------> Disk 4 ---->|
    |                                  |
    |<---------------------------------|                            

There are 9 jobs that move through the system. A single job alternately
accesses CPU and a disk many times -- this simulates the effect of
a real program using these types of resources. Of the 9 jobs, there
are 6 low priority jobs and 3 high priority jobs.

