Re: FileCopy overwrites the existing file

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Uwe Sieber wrote:
In 2003 the german computer magazine c't charged some recovery firms
(Ibas, Ontrack and Vogon) to restore a text file that had been
overwritten once with zeros.

None of the firms had been able to restore a single byte.

Were the companies instructed what kind of recovery is requested? Ie that the data had been overwritten with zeros once and we need what was before that? If not the company naturally recovered the last value ie zeros. I wouldn't assume such recovery is a regular offer.

Recovery firms are very successful restoring data from crashed, burned,
watered harddisks but restoring overwritten data seems be left to
agencies which make the impossible possible... I don't belive that it's
possible on a modern harddisk.


I would like to believe it as well. As a author of data destroying software it is *you* who should guarantee that the erased data is not recoverable, not vice versa. So I can't just say "I don't believe it is possible" or better take Anton's approach: "My software works: prove me that I'm wrong". By selling the software and ensuring your customers the data is really destroyed and not to be recovered (or at least by giving very high probability of that, like 99.9999%), you put your reputation with your words. I would really like to have such confidence, overwriting large file is quite expensive and if I had to do it, say 5 times instead of once it will take 5 times as long.
Btw, I've seen a software that allows a user to overwrite the sectors up to 100 hundred times! My first impression was that the authors were victims of paranoia. I don't think like that anymore, though they certainly exaggerated a bit.

--
Grzegorz Wróbel
http://www.4neurons.com/
677265676F727940346E6575726F6E732E636F6D
.

Relevant Pages

  • Re: FileCopy overwrites the existing file
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    (microsoft.public.win32.programmer.kernel)
  • Re: Inquiry:How to totally wipe out the entire hard drive
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  • Re: Windows restore
    ... server and my new server have no SP. ... The first restore, I choose the following: ... regsvr32 regwizc.dll ... C:\WINDOWS\system32\mscorier.dll: file exists, overwriting ...
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  • Re: what happens to deleted files
    ... It has never been done, not even by Dr. Gutmann himself, and he is the one who first advanced the theory that it might be possible to recover data from overwritten drives. ... The best that Dr. Gutmann could do with MFM was to show that there "might" be a possibility that some bits of data might be recoverable, he was never able to recover actual files and he has never been able to publicly demonstrate that he actually could recovery files on zero written drives, and nobody else either ever could. ... The reason that the US government or any other entities who work with very sensitive data might melt or destroy drives instead of securely overwriting them is not because of the possibility of data recovery on these drives, it is because of the possibility of user or software errors when doing the wiping. ... There is one area which can be of real concern with regards to wiped drives and where actual "bits" of data recovery could be made, cluster tips. ...
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