Re: netbsd-5.1 cpu probe/attach for 11/7xx?

[der Mouse <mouse%Rodents-Montreal.ORG@localhost>]

> ... the KA630 was designed so that MP systems can be done, it is not
> in general with shared memory.  Instead, each processor has its own
> memory, and you can share a small window of it.

Not all that small a window; the Qbus space is 4M (well, 4M minus 8K),
and the most RAM a KA6[23]0 can have is 16M.

> NUMA system, it would seem... :-)

Very NUMA!  I suppose for DEC's designed-for use case it was fine.

> I wonder if NetBSD could be tricked into handling such a machine.

That would be interesting.  It would probably be easiest to do it as
one NetBSD instance per CPU, with non-primary CPUs having no Qbus
devices, just a fast network interface built atop the doorbell
interrupt and shared memory (and perforce running diskless).  But
that's not really using it as a multiprocessor machine; it's just a way
to get the hardware running something.

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