On Sat, 23 Mar 1996, Jell-O wrote:

> Another error (I don't know if it's related or not) that I got after the
> system was idle for about ten minutes was the following:
> 
> Mar 23 20:44:46 myname /netbsd: ncrscsi 0: Resetting SCSI-bus (Timeout
> waiting for phase-change)
> 
> After the crashes when the HD light stays high, I've had problems with
> files and directories getting corrupted.

This sounds like what I've seen a number of times.  I don't know why, and 
I can't generally reproduce it easily, but one key difference is that in 
my case it's always after I've been driving the disk relatively hard.  
I've seen that same reset message, though.

I have a feeling that it's related to SCSI reselect, which is implemented 
in the 1.1 and -current SCSI drivers.  My alternative driver, the 'sbc' 
driver, doesn't handle disconnect/reselect and doesn't have this 
particular problem.  Unfortunately this causes other problems like clock 
slowdowns and poor responsiveness when using a slow SCSI device, e.g. a 
tape drive.

I wish I had an answer for you.  At least I'm not insane, though. :-)

--scott