>From Bill Studenmund's reply to David Gatwood 10/22 17:01:
>> Actually, I've thought of one more factor... as far back as I can
>> remember, I've had problems when using shutdown -r now.  I don't recall
>> whether shutdown -h now causes the problem or not, now that I think about
>> it -- which makes sense, since -r does reboot, while -h basically
>> approximates "it is now safe to shut of your macintosh"....
>> 
>> I'm trying a shutdown -h now from multi-user, rebooting from its prompt,
>> booting NetBSD....  No problems whatsoever....  Therefore, it seems to
>> only happen with a shutdown -r now....
>
>Does your drive go into some sort of sleep mode automatically? It could be
>that the on-disk cache is getting the sectors to write but not getting to
>send them out before MacOS resets the SCSI bus (and possibly the drive).
>
>Take care,
>
>Bill
>

I just caught the tail end of this discussion, but it reminds me of a 
possible source of data corruption.  Recently, many drives are shipping 
with "Write Caching" enabled, whereas previously this was rather 
uncommon.  This means that the drive returns 'Cmd Complete/NoError' 
before the data is actually written to the media.  The MacOS has 
provisions to ensure that the drive has flushed it's write cache to the 
media BEFORE turning off the power.  Does NetBSD provide similar 
safeguards?  Since the DRIVE remembers whether or not to 'write cache' it 
is possible that NetBSD would not have had 'write caching' problems when 
write caching was disabled, but now is having problems with write caching 
enabled.

...Harlan