HP-UX Scheduling Algorityms

From my reading HP-UX uses 4 different CPU scheduling algorithms: HP-UX Time-Share, HP Process Resource Manager, HP-UX Real-Time Scheduler, and POSIX-Compliant Real-Time Scheduler.

Here is where I am getting a little lost. Each algorithm seems to have its own priority, one higher than the other. Does this mean that HP-UX implements all four at the same time or does one choose to implement them singly and you have a choice of four algorithms?

Any insight would be appreciated.

Thank you,

Rich

See the page 90 of this pdf file
http://devresource.hp.com/drc/STK/docs/refs/proc_mgt.pdf

This is a nice document to understand process scheduling.

Cheers,

Awadhesh