Data recovery from Exabyte tape

Stuart Priest priest at
Tue Aug 16 06:13:16 EST 1994

In article <AA7557F6 at>, saper at UMICH.EDU ("Mark A. Saper") writes:
|> Computer experts:
|> Has anyone ever had the situation where a small tar file was written at the 
|> beginning of a 8 mm Exabyte tape which originally contained one big tar file?  
|> Does anyone have the expertise to recover the data remaining from the big tar 
|> file?  
|> We've found a company (Ontrack Data Recovery) that will do it, but it is rather 
|> pricey.  Has anyone used this or any other company?
|> Thanks for any help.
|> Mark 
|> ----------------------------------------------------------------------
|> Dr. Mark A. Saper                                      saper at
|> Biophysics Research Division                     Phone: (313) 764-3353    
|> University of Michigan                             FAX: (313) 764-3323          
|> 930 N. University Ave., Ann Arbor, MI 48109-1055
Dear Mark

The following answer was found on (with xmosaic or other WWW browser).

People often overwrite the beginning of large tar archive, leaving the
first bit of the tape overwritten and the rest presumably intact. This
is usually NOT recoverable.

However, if you're feeling lucky, you might (says Dave Olson
<olson at>) try something like 'mt fsf 4; mt bsf 2; tar xe' or
'mt fsf 4; mt bsr 2; tar xe'.  You might also try 'tar cv foo', where
'foo' is slightly bigger than what you overwrote the archive with the
first time, and pull the plug on the tape drive before it writes the
EOF. Then power it back up and try 'tar xe'.

If this sounds unlikely to work, you're right. Don't let it happen; use
the write protect tab.


                                (o  o)
 | Stuart Priest, Computer Manager       priest at        |
 | Protein Structure Group |
 ! Department of Chemistry                                               |
 | University of York               Telephone : 44 904 432592            |
 | Heslington, York YO1 5DD, U.K.         Fax : 44 904 410519            |
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