[Cialug] Tar file corruption

[David Bierce]

Since I have a known good copy of the data I care about, it has become more of an exercise in repairing tar corruption than anything.

Pretty sure HD repair tools won't work unless Mr. Gibson found a way to fixed bad actuators/arms.  Before it totally stopped worked...it was making clicking noises like it found some of Heisenberg's Blue Candy  :) .


On Apr 30, 2013, at 2:22 PM, Scott Yates wrote:

> One last thought.  If the drive is available to offline, you might try
> spinrite, or other disk based recovery options to get a clean copy of the
> archive.
> 
> 
> On Tue, Apr 30, 2013 at 2:18 PM, Jeffrey Ollie <jeff at ocjtech.us> wrote:
> 
>> On Tue, Apr 30, 2013 at 10:58 AM, David Bierce <david at bierce.org> wrote:
>>> I have a tar file that was bzip2 compressed and had a few blocks to bad
>> in media transfer, After pulling out the bad blocks, the reconstituted tar
>> file appears to only function until the place in the file where the first
>> block was corrupted.  After the first block it just doesn't read the rest
>> of the data.  I've tried to read the file ignoring zero data, which just
>> pulls a bunch of junk metadata and file names after the empty block.  I've
>> tried to extract it using CPIO, which has the same problem after the empty
>> block.
>>> 
>>> Does anyone know of a tool that can repair tar files, or at least, try.
>> Or it is time time to go digging deep into the file or give up :)
>> 
>> The problem isn't the tar file, the problem is the bzip2 compression.
>> bzip2 compresses things as a stream of blocks, with successive blocks
>> being compressed dependin on what was in previous blocks, so if one or
>> more blocks is corrupted, all subsequent blocks are corrupt.
>> 
>> At least on linux, there's a bzip2recover program which might be able
>> to recover some data, but you'll want to start with the original
>> corrupted file, not the one you edited.
>> 
>> --
>> Jeff Ollie
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