>> BTW:  I'd still be interested to know whether there would be problems
>> using an ISA bus mastering card in a >16 MB machine, if anyone can
>> enlighten me.
>AFAIK, and I have no contact with the core team, bounce buffers for DMA
>transfers over 16MB are as-yet unimplemented.  They are probably not far
>away, but this is a guess (EISA might come first :)).

Actually ... will there be a problem?  I was under the impression that mbufs
(the buffers used by the networking code) are allocated at boot time, and thus
would probably all be below the 16Mb line.  If that's not the case, you could
hack your mbuf allocator so it didn't allocate buffers above 16Mb (it's harder
to do this for disk controllers, since you sometimes want to do DMA directly
into the user's address space).

--Ken (who freely admits to not knowing that much about Unix vm systems :-) )