Dual Processors
  • Jim
  • Yokemate of Keyboards
    Yokemate of Keyboards
    Posts: 4977 from 2009/1/28
    From: Delaware, USA

    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"
  • »20.06.13 - 00:11