PReP is not the same as CHRP.  PReP machines do not have the same
Open Firmware device tree, client services, and RTAS.  I believe that some
PReP machines can be upgraded or boot a CHRP emulator, but I'm not sure.

	RPA is the IBM-specific continuation of CHRP.  It supports Open
Firmware (device tree, client services, RTAS), but it may have different
devices than specified in the CHRP specification.  It may use different
interrupt controllers (not OpenPIC), etc.

David