Re: Q: double Boot for SMP 7300
That would explain it, because the youngest macos I have is 8.1. I
take it that the latest dual G4s are a different architecture?
If he doesn't change kernels a lot he can use the boot floppy
method, which works rather reliably, ie., whenever you want to boot
linux push the floppy into the drive and have it boot the kernel
from there. I used that quite happily on my 7200 until I finally
got around the stuffit chicken/egg puzzle.
a
Benjamin Herrenschmidt wrote:
>
> >I think that the answer to the original question is that when
> >booting from BootX, you have to have a kernel that supports SMP, but
> >the stock kernel does not, so you have to build your own, and put it
> >where BootX can find it.
> >
> >I don't think there is anything that you need to do to your PRAM,
> >whatever that is, or your nvram, if you are using BootX. I use
> >BootX on my dual processor machine, it works fine, and I have never
>
> The problem is more nasty. With the "old" MP mecanism (Apple/Daystar),
> the kernel cannot take over the second CPU if MacOS already started it.
>
> It was not a problem until MacOS 8.6 or so. At this point, Apple changed
> MacOS nanokernel to be fully SMP and now starts the second CPU early during
> boot, long before BootX takes over.
>
> miBoot still works as it is started before the RAM-based nanokernel (out of
> the ROM-based one which is still the old one).
>
> I may have a way to work around the problem from BootX by sending an interrupt
> to the second CPU to force it to reach the interrupt vector (provided
> that MacOS
> leaves it running with MSR:EE enabled). However, this would require some
> hacking
> I don't have the corresponding hardware to do.
>
> Ben.
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