SUMMARY: HP DAT overwritten tape error recovery (ADDENDA)

From: Tom Kinter (tmk@mayo.edu)
Date: Wed Jul 12 2000 - 14:23:10 CDT


Sun Managers,

Thanks for more responses!

The question:
  I have an HP C5653A SurStore DAT24eU external tape drive attached to a
  SPARCstation 5 running Solaris-2.7. I had a tape filled with files
  containing data. Then, accidentally I wrote a file at the beginning of
  the tape. My thought is that if I could get past this file, I could get
  into the remaining good files and do some recovery. The problem is that
  I can't seem to get past this initial file. I tried the mt command to
  skip past filemarks and I tried a program usind open/read/ioctl to read
  records and skip filemarks. I always end up with an "I/O error" and it
  will not go any further than the first file. Are the any ways to get
  around this problem?

The new consensus:

  1) Rewind the tape

  2) Start writing a file that is bigger than the one that was accidentally
     written on the tape

  3) When you think it is past the offending EOT mark, pull the power
     plug on the tape drive (this could hang up your system). This keeps the
     EOT mark from being automatically written

  4) When you get things going again and the tape rewound, skip over one
     EOF mark

  Now you are sitting at the beginning of the first good tape file!

I had contacted one data recovery house:
  $250 initial fee
  $500 - $3500 for recovery
Ouch!

With these new suggestions in hand and the cost factor urging me on, I
did try it out on a test tape. It worked! Now I will try it on the real
tape. The trick is in knowing when to "pull the plug". I can find the
size of the offending file and estimate the time needed to write past
the EOT (but not too far past).

Isn't this group great!!!!

Thanks for the new responses:
  Gaylord Holder
  Brooke King
  Mike Salehi
  Roy Ramberg
  R. Jesus Garcia
  Nadya Williams
  Bolson
  Chris Marble

Tom
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  Tom Kinter tmk@mayo.edu 507-284-4981
     Mayo Foundation Rochester MN 55905 USA
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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