Follow up on the lost interrupts:

It turns out I don't have a handy PS to test the PS theory.  The only
ones I have depend on the motherboard "soft power" and I would
have to figure out how to get it to turn on..... so I didn't do
that.

I *did* put both drives on the same ribbon cable, with one master and
the other slave.  I've been abusing all three drives for about 40 minutes
now, and have yet to see a single "lost interrupt" message in the
log.

With master/slave on the same cable, I can sustain about 10 MB/s
between these two drives, which is not too bad.  Raw dd from the
drive to /dev/null appears to be able to do about 25 MB/s.

I think I'm in business.  Thanks for the help, all.


-dgl-

P.S. The good news is that this works now, and it appears to be a problem with
using the two drives simultaneously on two channels on the same PCI card.

The bad news is that now it _really_ smells like a software issue.