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Data Recovery tool

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(@keeper)
Estimable Member
Joined: 17 years ago
Posts: 106
Topic starter  

I'd like to know which application is the one mentioned in Here.

[...] we have developed a new tool capable of rescuing damaged compressed files,
according to the DEFLATE compression scheme, even though the header block is missing or corrupted.


   
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(@mscotgrove)
Prominent Member
Joined: 17 years ago
Posts: 940
 

Most compression methods work by in effect taking out repeating strings. If a string has been seen in a file it is replaced by a reference. With this method, a history block of data is built up. If the start of the compressed data is missing, the original history data cannot be reconstructed.

On a compressed NTFS disk, data is compressed in 4K blocks so recontructing partial data will be possible, after a 4K (expanded data) boundary. With a ZIP file I would expect there to be a lot of guesses in the final result. Decompression has to start with the start of the compressed data stream.

For a ZIP file containing many files, it will be possible to decompress separate, but complete files without the main ZIP file header. Finding a file start location within a multiple file ZIP file is easy. Recreating missing data is not possible.


   
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jhup
 jhup
(@jhup)
Noble Member
Joined: 16 years ago
Posts: 1442
 

http//en.wikipedia.org/wiki/DEFLATE


   
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