Summary: Hard disk errors on a 3b1; HwNote13

[John B. Milton]

In article <468 at manta.pha.pa.us> brant at manta.pha.pa.us (Brant Cheikes) writes:
>Let me begin with a sincere and appreciative public THANK YOU! to John
You're welcome.

...
>>Ahh! Wouldn't you know it! I've got news stomping on my soft blocks!
Excuse my attempt at levity. Yes, there is some concern here. In my case I have
not gotten anymore hits on these spots. A good way to check whether a certain
HDERR is hard (always bad), soft (sometimes bad), or transient (usually not
related to the disk at all), is to:

cp /dev/rfp000 /dev/null

Ignore the "bad copy to /dev/null", and check /usr/adm/unix.log to see if you
have any new messages. Track down the file, and:

ln file /usr/adm/bad+junk

Just to make sure the bad spot doesn't get loose. Repeat this at different
times of the day. Try to pick times when your machine is under extreme
conditions: 5-6p.m. for lowest line voltage, 3a.m. for highest. Afternoon, or
whenever for highest temperature, etc. You might even set up a temporary cron
line to do this. You could also kick a second one off 5 minutes after the
first to see if your errors are seek related. Don't do too much of this, as it
can put a lot of wear on the moving parts of you head assembly!

REMEMBER! when smgr finds that /usr/adm/unix.log has exceeded 10k in size,
it quietly deletes it! Shame on you if you don't have something like this run
out of cron every night:

cd /usr/adm
if [ -f unix.log ]; then
	cat unix.log >>UNIX.log
	rm unix.log
fi

About once a month, I go through this file and delete all the FDERR lines from
floppy formatting. After you have collected enough HDERR lines, you can get
all the suspect files in one place and flog them to get a feel for how "hard"
a given bad spot is. If you get a continuous stream of transient (one hit)
spots when scanning the whole disk, it is probably electronics, and not the
hard disk surface.

John
-- 
John Bly Milton IV, jbm at uncle.UUCP, n8emr!uncle!jbm at osu-cis.cis.ohio-state.edu
(614) h:294-4823, w:764-2933;  Got any good 74LS503 circuits?