>Were you referring to probing the SBI nexus space for UBAS or probing
>the Unibus I/O register space on the UBA?

The latter -- the 16 SBI nexi tell you what is plugged into them,
if anything.  On the 780, though, there is a special Unibus error
register in the adapter, that gets set in some case I never really
learned.

>Even with sanely-designed hardware, consoles are a `problem child' for
>the autoconfiguration code ...

Well, no and yes -- consider the Vax, for instance, where the console
is always present and does not need to be configured as a tty -- it is
just there.  (If you need to hook it into the rest of the system, e.g.,
to do statistics, you do this much like a pty pseudo-device attach.)

Chris