Exabyte tape oxidation problem ?? (L

[Eric Ho]

Has anyone tried putting the Exabyte tape (I'm using the Sony 8mm video-8
P6-120MP) in the Exabyte drive for say more than 6 days with dumps added
onto the tape every night and that it'll still work say after a week ?

I'm suspecting that putting the tape inside the drive for more than a few
days would cause oxidation problem on the tape.

The thing is that I'm doing nightly dumps of a single partition on my disk
onto my Exabyte tape.  I figured that since my partition is relatively
small, a single tape can hold at least 2 weeks of nightly dumps.

So I wrote a script to automate my nightly dumps -- of course, it'll do
all the necessary 'mt ... fsf <n>' so as to add the dumps onto the tape
correctly.  The strange thing is that after several nights -- I always got
this type of errors :-

==========================================
/etc/dump 1usf 145000 cognito:/dev/nrxb0 /dev/rxy1g
  DUMP: Date of this level 1 dump: Thu Sep 21 02:02:25 1989
  DUMP: Date of last level 0 dump: Fri Sep  8 02:33:08 1989
  DUMP: Dumping /dev/rxy1g (/people) to /dev/nrxb0 on host cognito
  DUMP: mapping (Pass I) [regular files]
  DUMP: mapping (Pass II) [directories]
  DUMP: mapping (Pass II) [directories]
  DUMP: mapping (Pass II) [directories]
  DUMP: estimated 167606 blocks (81.84MB) on 0.04 tape(s).
  DUMP: dumping (Pass III) [directories]
  DUMP: write: I/O error
  DUMP: Tape write error 5 feet into tape 1
  DUMP: fopen on /dev/tty fails
  DUMP: Bad return code from dump: 255

Sep 21 02:04:20 cognito vmunix: xb0: SCSI device error cs=c0<CC,ERR> ss=0x2 (check condition) ds=404<TME> (hardware error)
==========================================

I've even cleaned the drive and still got similiar error messages.

Then, to determine if it is an oxidation problem or an actual
drive/controller problem, I wrote a simple script to dump a 84meg
partition onto a single (brand new) tape 10 times in one shot -- i.e. dump
the partition, rewind the tape, forward the tape, dump the partition
again, then rewind, then forward, and then dump again, ...etc...  So,
after 10~11 dumps, the tape should be about half filled.  And to my
surprise, it went just fine.

Here is my simple script :-
==========================================
#!/bin/csh -fx
mt -f /dev/rxb0 rew

dump 0unsf 145000 /dev/rxb0 /dev/rsd0e
mt -f /dev/rxb0 rew

mt -f /dev/nrxb0 fsf 1
dump 0unsf 145000 /dev/nrxb0 /dev/rsd0e
mt -f /dev/rxb0 rew

mt -f /dev/nrxb0 fsf 2
dump 0unsf 145000 /dev/nrxb0 /dev/rsd0e
mt -f /dev/rxb0 rew

mt -f /dev/nrxb0 fsf 3
dump 0unsf 145000 /dev/nrxb0 /dev/rsd0e
mt -f /dev/rxb0 rew

mt -f /dev/nrxb0 fsf 4
dump 0unsf 145000 /dev/nrxb0 /dev/rsd0e
mt -f /dev/rxb0 rew

mt -f /dev/nrxb0 fsf 5
dump 0unsf 145000 /dev/nrxb0 /dev/rsd0e
mt -f /dev/rxb0 rew

mt -f /dev/nrxb0 fsf 6
dump 0unsf 145000 /dev/nrxb0 /dev/rsd0e
mt -f /dev/rxb0 rew

mt -f /dev/nrxb0 fsf 7
dump 0unsf 145000 /dev/nrxb0 /dev/rsd0e
mt -f /dev/rxb0 rew

mt -f /dev/nrxb0 fsf 8
dump 0unsf 145000 /dev/nrxb0 /dev/rsd0e
mt -f /dev/rxb0 rew

mt -f /dev/nrxb0 fsf 9
dump 0unsf 145000 /dev/nrxb0 /dev/rsd0e
mt -f /dev/rxb0 rew

mt -f /dev/nrxb0 fsf 10
dump 0unsf 145000 /dev/nrxb0 /dev/rsd0e
mt -f /dev/rxb0 rew
####		   END  OF  ~/try.csh
==========================================

Here is the response I get back :-
==========================================
cognito-eho(10)-[/]: ~/try.csh
mt -f /dev/rxb0 rew
dump 0unsf 145000 /dev/rxb0 /dev/rsd0e
  DUMP: Date of this level 0 dump: Fri Sep 22 15:26:31 1989
  DUMP: Date of last level 0 dump: the epoch
  DUMP: Dumping /dev/rsd0e (/spare) to /dev/rxb0
  DUMP: mapping (Pass I) [regular files]
  DUMP: mapping (Pass II) [directories]
  DUMP: estimated 173726 blocks (84.83MB) on 0.04 tape(s).
  DUMP: dumping (Pass III) [directories]
  DUMP: dumping (Pass IV) [regular files]
  DUMP: 72.91% done, finished in 0:01
  DUMP: DUMP: 173726 blocks (84.83MB) on 1 tape
  DUMP: DUMP IS DONE
  DUMP: level 0 dump on Fri Sep 22 15:26:31 1989
  DUMP: Tape rewinding
mt -f /dev/rxb0 rew
mt -f /dev/nrxb0 fsf 1
dump 0unsf 145000 /dev/nrxb0 /dev/rsd0e
  DUMP: Date of this level 0 dump: Fri Sep 22 15:35:42 1989
  DUMP: Date of last level 0 dump: the epoch
  DUMP: Dumping /dev/rsd0e (/spare) to /dev/nrxb0
  DUMP: mapping (Pass I) [regular files]
  DUMP: mapping (Pass II) [directories]
  DUMP: estimated 173726 blocks (84.83MB) on 0.04 tape(s).
  DUMP: dumping (Pass III) [directories]
  DUMP: dumping (Pass IV) [regular files]
  DUMP: 79.95% done, finished in 0:01
  DUMP: DUMP: 173726 blocks (84.83MB) on 1 tape
  DUMP: DUMP IS DONE
  DUMP: level 0 dump on Fri Sep 22 15:35:42 1989
  DUMP: Tape rewinding
mt -f /dev/rxb0 rew
mt -f /dev/nrxb0 fsf 2
dump 0unsf 145000 /dev/nrxb0 /dev/rsd0e
  DUMP: Date of this level 0 dump: Fri Sep 22 15:45:11 1989
  DUMP: Date of last level 0 dump: the epoch
  DUMP: Dumping /dev/rsd0e (/spare) to /dev/nrxb0
  DUMP: mapping (Pass I) [regular files]
  DUMP: mapping (Pass II) [directories]
  DUMP: estimated 173726 blocks (84.83MB) on 0.04 tape(s).
  DUMP: dumping (Pass III) [directories]
  DUMP: dumping (Pass IV) [regular files]
  DUMP: 80.13% done, finished in 0:01
  DUMP: DUMP: 173726 blocks (84.83MB) on 1 tape
  DUMP: DUMP IS DONE
  DUMP: level 0 dump on Fri Sep 22 15:45:11 1989
  DUMP: Tape rewinding
mt -f /dev/rxb0 rew
mt -f /dev/nrxb0 fsf 3
dump 0unsf 145000 /dev/nrxb0 /dev/rsd0e
  DUMP: Date of this level 0 dump: Fri Sep 22 15:55:19 1989
  DUMP: Date of last level 0 dump: the epoch
  DUMP: Dumping /dev/rsd0e (/spare) to /dev/nrxb0
  DUMP: mapping (Pass I) [regular files]
  DUMP: mapping (Pass II) [directories]
  DUMP: estimated 173726 blocks (84.83MB) on 0.04 tape(s).
  DUMP: dumping (Pass III) [directories]
  DUMP: dumping (Pass IV) [regular files]
  DUMP: 79.64% done, finished in 0:01
  DUMP: DUMP: 173726 blocks (84.83MB) on 1 tape
  DUMP: DUMP IS DONE
  DUMP: level 0 dump on Fri Sep 22 15:55:19 1989
  DUMP: Tape rewinding
mt -f /dev/rxb0 rew
mt -f /dev/nrxb0 fsf 4
dump 0unsf 145000 /dev/nrxb0 /dev/rsd0e
  DUMP: Date of this level 0 dump: Fri Sep 22 16:06:10 1989
  DUMP: Date of last level 0 dump: the epoch
  DUMP: Dumping /dev/rsd0e (/spare) to /dev/nrxb0
  DUMP: mapping (Pass I) [regular files]
  DUMP: mapping (Pass II) [directories]
  DUMP: estimated 173726 blocks (84.83MB) on 0.04 tape(s).
  DUMP: dumping (Pass III) [directories]
  DUMP: dumping (Pass IV) [regular files]
  DUMP: 79.33% done, finished in 0:01
  DUMP: DUMP: 173726 blocks (84.83MB) on 1 tape
  DUMP: DUMP IS DONE
  DUMP: level 0 dump on Fri Sep 22 16:06:10 1989
  DUMP: Tape rewinding
mt -f /dev/rxb0 rew
mt -f /dev/nrxb0 fsf 5
dump 0unsf 145000 /dev/nrxb0 /dev/rsd0e
  DUMP: Date of this level 0 dump: Fri Sep 22 16:17:39 1989
  DUMP: Date of last level 0 dump: the epoch
  DUMP: Dumping /dev/rsd0e (/spare) to /dev/nrxb0
  DUMP: mapping (Pass I) [regular files]
  DUMP: mapping (Pass II) [directories]
  DUMP: estimated 173726 blocks (84.83MB) on 0.04 tape(s).
  DUMP: dumping (Pass III) [directories]
  DUMP: dumping (Pass IV) [regular files]
  DUMP: 79.02% done, finished in 0:01
  DUMP: DUMP: 173726 blocks (84.83MB) on 1 tape
  DUMP: DUMP IS DONE
  DUMP: level 0 dump on Fri Sep 22 16:17:39 1989
  DUMP: Tape rewinding
mt -f /dev/rxb0 rew
mt -f /dev/nrxb0 fsf 6
dump 0unsf 145000 /dev/nrxb0 /dev/rsd0e
  DUMP: Date of this level 0 dump: Fri Sep 22 16:29:49 1989
  DUMP: Date of last level 0 dump: the epoch
  DUMP: Dumping /dev/rsd0e (/spare) to /dev/nrxb0
  DUMP: mapping (Pass I) [regular files]
  DUMP: mapping (Pass II) [directories]
  DUMP: estimated 173726 blocks (84.83MB) on 0.04 tape(s).
  DUMP: dumping (Pass III) [directories]
  DUMP: dumping (Pass IV) [regular files]
  DUMP: 79.64% done, finished in 0:01
  DUMP: DUMP: 173726 blocks (84.83MB) on 1 tape
  DUMP: DUMP IS DONE
  DUMP: level 0 dump on Fri Sep 22 16:29:49 1989
  DUMP: Tape rewinding
mt -f /dev/rxb0 rew
mt -f /dev/nrxb0 fsf 7
dump 0unsf 145000 /dev/nrxb0 /dev/rsd0e
  DUMP: Date of this level 0 dump: Fri Sep 22 16:42:35 1989
  DUMP: Date of last level 0 dump: the epoch
  DUMP: Dumping /dev/rsd0e (/spare) to /dev/nrxb0
  DUMP: mapping (Pass I) [regular files]
  DUMP: mapping (Pass II) [directories]
  DUMP: estimated 173726 blocks (84.83MB) on 0.04 tape(s).
  DUMP: dumping (Pass III) [directories]
  DUMP: dumping (Pass IV) [regular files]
  DUMP: 79.12% done, finished in 0:01
  DUMP: DUMP: 173726 blocks (84.83MB) on 1 tape
  DUMP: DUMP IS DONE
  DUMP: level 0 dump on Fri Sep 22 16:42:35 1989
  DUMP: Tape rewinding
mt -f /dev/rxb0 rew
mt -f /dev/nrxb0 fsf 8
dump 0unsf 145000 /dev/nrxb0 /dev/rsd0e 
  DUMP: Date of this level 0 dump: Fri Sep 22 16:56:06 1989
  DUMP: Date of last level 0 dump: the epoch
  DUMP: Dumping /dev/rsd0e (/spare) to /dev/nrxb0
  DUMP: mapping (Pass I) [regular files]
  DUMP: mapping (Pass II) [directories]
  DUMP: estimated 173726 blocks (84.83MB) on 0.04 tape(s).
  DUMP: dumping (Pass III) [directories]
  DUMP: dumping (Pass IV) [regular files]
  DUMP: 79.33% done, finished in 0:01
  DUMP: DUMP: 173726 blocks (84.83MB) on 1 tape
  DUMP: DUMP IS DONE
  DUMP: level 0 dump on Fri Sep 22 16:56:06 1989
  DUMP: Tape rewinding
mt -f /dev/rxb0 rew
mt -f /dev/nrxb0 fsf 9
dump 0unsf 145000 /dev/nrxb0 /dev/rsd0e
  DUMP: Date of this level 0 dump: Fri Sep 22 17:10:17 1989
  DUMP: Date of last level 0 dump: the epoch
  DUMP: Dumping /dev/rsd0e (/spare) to /dev/nrxb0
  DUMP: mapping (Pass I) [regular files]
  DUMP: mapping (Pass II) [directories]
  DUMP: estimated 173726 blocks (84.83MB) on 0.04 tape(s).
  DUMP: dumping (Pass III) [directories]
  DUMP: dumping (Pass IV) [regular files]
  DUMP: 79.54% done, finished in 0:01
  DUMP: DUMP: 173726 blocks (84.83MB) on 1 tape
  DUMP: DUMP IS DONE
  DUMP: level 0 dump on Fri Sep 22 17:10:17 1989
  DUMP: Tape rewinding
mt -f /dev/rxb0 rew
mt -f /dev/nrxb0 fsf 10 
dump 0unsf 145000 /dev/nrxb0 /dev/rsd0e 
  DUMP: Date of this level 0 dump: Fri Sep 22 17:25:08 1989
  DUMP: Date of last level 0 dump: the epoch
  DUMP: Dumping /dev/rsd0e (/spare) to /dev/nrxb0
  DUMP: mapping (Pass I) [regular files]
  DUMP: mapping (Pass II) [directories]
  DUMP: estimated 173726 blocks (84.83MB) on 0.04 tape(s).
  DUMP: dumping (Pass III) [directories]
  DUMP: dumping (Pass IV) [regular files]
  DUMP: 79.75% done, finished in 0:01
  DUMP: DUMP: 173726 blocks (84.83MB) on 1 tape
  DUMP: DUMP IS DONE
  DUMP: level 0 dump on Fri Sep 22 17:25:08 1989
  DUMP: Tape rewinding
mt -f /dev/rxb0 rew
cognito-eho(11)-[/]: 
==========================================

The only difference this time of course is that I'm doing the 10 dumps in
one shot (it only took me ~2hrs to do the 10 dumps) whereas before I just
left the tape inside the drive for days without removing it from the drive
at all.

Now, I just wondered if anyone has encountered similiar situations before.
I'm kind of baffled.  It looks to me, as of now, that it is a tape problem
rather than a drive problem.  Also, besides these 10~11 dumps that I've
just done today, I've been able to put 3 dumps (of 400 meg each) onto a
single tape in the past without a hitch but I usually put that tape into
the drive right before the dump is to be done and remove the tape when the
dump is done -- i.e. the tape has never been left inside the drive for
more than 36 hours.


Eric Ho  
Princeton University
eho at confidence.princeton.edu