Hello Kent,

  K> I have a 2940UW and as far as I can determine, under the best
   > conditions with NetBSD 1.5.x, it can't achieve even 20Mb/s in
   > benchmarks with (three different) scsi2wide drives that should be
   > able to approach 40Mb/s.

I think Fast, Wide SCSI-2 would be limited to 20Mb per second 10MHz x
2 bytes per transfer absolute tops.  This is probably academic anyway
since a single drive isn't likely to sustain enough throughput to
saturate the SCSI bus (it has to sit and wait for the data to fly
under the head).

  K> Since the same machine runs a 7200 ata100 at 40Mb/s (even writes)
   > with the same benchmarks, can I assume a problem with NetBSD and
   > the Adaptek firmware (even updated to the latest version) or
   > hardware?

I don't know how much of a role the Adaptec firmware plays once BSD
has booted.  In any case, you can't expect Ultra throughput from
SCSI-2 devices.

Hope this helps,
  - Andy Ball.