I have a working Micropolis 135Mb drive on a Sun 3/50 that boots fine
at SCSI 0, with the command 'b sd(0,0,0)'.  I've been trying to narrow
down the reasons why my system doesn't recognize any other scsi drives
that get hooked up.

When I try to move the existing drive at ID=0 to another ID...
All of the following configurations result in the same error message:
  bdevvp: bad open
  no ether device opened
  input ether device name (le%d[01], ie%d[01], gn%d[01], ec%d[01], ):
[at which this point I enter 'le0' and it tries to rarp-boot]

SCSI id		Boot command
1		sd(0,4,0)
2		sd(0,8,0)
4		sd(0,10,0)

No other boot commands do anything with any of the ID's listed
other than return "scsi: select failed".  (I went through all the
numbers and A-F for the boot command...nada.)

If anyone has ideas on what's wrong with my hardware/configuration,
I'd be very grateful to hear from you.

Regards,
Marc.