I took another look at the boot CD-ROM I burned last night and noticed that
the relevant file was named OFWBOOT.XCO, not OFWBOOT.COF as I had been
typing.  The boot target of scsi-int/@3:0,OFWBOOT.XCO worked like a charm.
(Well it bitched a lot about the Visioneer Paper Port on the external bus,
but that didn't prevent anything.)

Now I just need to figure out why I get an I/O error whenever I reference
the CD-ROM and can't mount it.

Is there any significance to the fact that the external bus gets probed
first?  Given the way we dynamically number devices that seems like the
wrong order.

Signature failed Preliminary Design Review.
Feasibility of a new signature is currently being evaluated.
h.b.hotz@jpl.nasa.gov, or hbhotz@oxy.edu