Subject: Re: Hmm. Stability problems.
To: Allen Briggs <briggs@puma.bevd.blacksburg.va.us>
From: Scott Reynolds <scottr@edsi.org>
List: port-mac68k
Date: 11/07/1995 23:27:33
On Sat, 21 Oct 1995, Allen Briggs wrote:

> Hmmm...  What version of mac68k5380.c do you have?

Always the latest and greatest.  I've also been experimenting with the 
ncr5380.c code to see if I can figure out the problem.

> > So far, I've drawn a correlation between:
> > 	panic: ffs_read 0  <-and->  extended heavy load (load avg > 4.0)
> 
> Hmm...   I haven't seen this...

This one hasn't gone away, or at least it has shown up in several 
different but apparently related forms.  There is always some period of 
intense disk activity before it happens.  As far as I can tell, though, I 
never run out of swap; 8M RAM, 32M swap, and I haven't seen it top 24M 
used yet.

One common factor that seems to be coming up is blocks from apparently 
random places get thrown into another part of the filesystem.  I looked 
in my /usr/lost+found and found (get this!) 4 copies of the /root 
directory.  I have no idea how they could have gotten there, except for 
some sort of overlap.  The fake disklabel doesn't seem to think there is, 
but now that I grabbed the latest snapshot with fsdb I'm going to see if 
I can figure it out.

Oh, note that I have separate / and /usr filesystems.  I have space 
allocated for a /var, but I've been planning some experiments if this 
machine will manage to stay online.

Possible problems:  bad cable?  bad termination?  the driver doesn't like 
having these 3 devices attached to the SCSI bus?  the driver has some 
weird bug that is only tickled by my strange SCSI disk (was originally a 
part of an IBM RAID subsystem)?

Since I've heard of at least one other report of scrambled filesystems, 
I'd suspect the driver, or maybe termination.  The cable seems to be 
perfectly good, and in fact I just replaced it with a brand new one to 
make sure.

> > 	panic: bad dir  <-and->  any audio access of my CD-ROM.
> 
> ... and I don't use a CD-ROM drive much under BSD.

I haven't had this particular panic, and neither have I tried any CDDA 
stuff.  I've had regular (every 2-3 days) crashes nonetheless.

> > I built a miniroot last night, just to prove to myself that it could be
> > done, and then booted from it to see if I could get this Archive Viper 150
> > to run.

I verified since I wrote this that reading a tape works just fine.  In 
fact, I've taken to converting my filesystems to a level 2, and now I 
just load the system from tape when I have problems.  Unfortunately, 
since I haven't figured out what to do to make the tape drive actually 
write a tape, I kinda have to transfer stuff out by modem and download it 
to MacOS to get it on a tape to be restored in the event of a problem.  
"Ick."

--scott