I found my machine in db> mode today.  I viewed the messages files and 
got this snip:  An help is appreciated in finding the the cause.  Thanks.

------------ begin
Mar 17 07:00:36 jupiter /netbsd: assertion "cp" failed: file 
"../../../../dev/pc
i/ncr.c", line 5173
Mar 17 07:00:36 jupiter /netbsd: ncr0 targ 0?: ERROR (80:100:ab) (8/13) @ 
(61a0c
c:e000000).
Mar 17 07:00:36 jupiter /netbsd: ncr0: restart (fatal error).
Mar 17 07:00:36 jupiter /netbsd: sd0(ncr0:0:0): COMMAND FAILED (9 ff) 
@f87a5200.
Mar 17 07:00:37 jupiter /netbsd: sd0(ncr0:0:0): COMMAND FAILED (9 ff) 
@f87a5400.
Mar 17 07:00:37 jupiter /netbsd: sd0(ncr0:0:0): COMMAND FAILED (9 ff) 
@f87a5600.
Mar 17 07:00:37 jupiter /netbsd: sd0(ncr0:0:0): COMMAND FAILED (9 ff) 
@f87a5800.
Mar 17 07:00:37 jupiter /netbsd: ncr0: reset by timeout.
Mar 17 07:00:37 jupiter /netbsd: sd0(ncr0:0:0): FAST SCSI-2 100ns (10 
Mb/sec) of
fset 8.
Mar 17 07:00:37 jupiter /netbsd: sd0(ncr0:0:0): not ready, data = 00 00 
00 00 04
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Mar 17 07:00:37 jupiter last message repeated 3 times
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^Mar 18 02:01:00 jupiter /netbsd: 
sd1(ncr0:1
:0): FAST SCSI-2 100ns (10 Mb/sec) offset 8.
Mar 18 02:01:46 jupiter /netbsd: sd2(ncr0:2:0): FAST SCSI-2 100ns (10 
Mb/sec) of
fset 8.
Mar 18 02:02:36 jupiter /netbsd: sd0(ncr0:0:0): medium error, info = 
186360 (dec
imal), data = 00 00 00 00 14 00 00 00 00 00 00 00 00 00 00 00 00 00 00 04
...
-------------end



..............          ....................................
Thomas T. Thai          Infomedia Interactive Communications
tom@iic.net             TEL 612.376.9090 * FAX 612.376.9087