If you anonymous-FTP to blackwidow.cwru.edu, cd to
/home/msokolov/pub/toys/netbsd, and download gennetbsd.gz, you'll get a GENERIC
NetBSD kernel that does SCSI on KA42/41 (VS3100 M30/38/40/48 and MV3100
M10/10e/20/20e) more or less right. (It's "right" in the sense that it boots
from SCSI disks whereas the stock v1.3 which it is based on doesn't. It's "more
or less" in the sense that it still pours warning messages on the console.)

I haven't done any performance tests on it, but since I haven't done anything
special to make it PIO, I assume that it's DMA.

Have fun.

Sincerely,
Michael Sokolov
Phone: 440-449-0299
ARPA Internet SMTP mail: msokolov@blackwidow.cwru.edu