There is something definitely going on with the MSCP driver in 1.3K
(-current). I've got a Sigma Information System RQ11D controller talking to
two Micropolis 1568's and a Maxtor XT8760E ESDI drive. 

If I boot the system diskless and work from NFS mounted file systems only,
then I don't have a problem, if however I mount one of the disks and start
more than one process beating on the disk (for example I was trying to do a
make build with DESTDIR set to the disk and in another session I was doing
the occasional ls -l to see what had been created on the disk.) eventually
both processes will hang in a diskwait. Then anything that trys to touch
the disk hangs. Then the only thing I can do is reboot since I still
haven't figured out how to pop into db when this happens.

--Chuck