Yokemate of Keyboards
Posts: 4977 from 2009/1/28
From: Delaware, USA
Quote:Andreas_Wolf wrote:
> One higher instance must be present to control shared resources like RAM, bus
> access etc. On modern processors this may be done in silicon (hypervisor), but
> on G4 or G5 this would be done in software.
The PPC970 CPUs themselves have hypervisor capability (inherited from POWER4 which was IBM's first hypervisor-enabled CPU) but which is disabled on Apple's G5 machines via OpenFirmware (and cannot be re-enabled). I suspect this may have been due to a deal with IBM so that IBM's server customers wouldn't even consider buying cheaper
Xserve G5 instead.
Are you absolutely certain it can't be re-enabled Andreas?
That would make multiprocessing easier.
Its obviously still possible without it, but having something supervising both cores would be very handy.
Edit - Yet another dumb question answered by research. Apparently it can't be (unless its possible by completelly replacing Open Firmware - and how would you do that?).
[ Edited by Jim 20.06.2013 - 00:19 ]"Never attribute to malice what can more readily explained by incompetence"
