Silly question about secure deletion of files

[Faramir]

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Robert J. Hansen escribió:
...
> With a defrag, if you successfully rearrange 95% of the affected blocks
> then you've substantially improved your drive performance.  Sure, it'll
> report that it's done 100%, but who cares, really?

  Not me ;)

> With disk overwriting, if you successfully overwrite 95% of your
> sensitive data, you may still be putting yourself at substantial risk.
> Especially since it will report that it overwrote all your data.

  Ok, that answers my question.

  Usually I don't see thing from the same point of view than you, I
mean, usually I think about "secure deletion" if the file can't be fully
recovered by the use of a simple recovery tool (let's say, Norton
unDelete)... but of course, in other context, fragments of information
can be very dangerous and the attacker can bring the hdd to an
specialized lab...
  In other words, if I intend to destroy the PhD thesis of my brother,
overwritting 50% of it would be more than enough to make him cry like a
baby. But if I intend to destroy the list of infiltrated agents of the
Rebel Alliance, even a 5% of the list would make Darth Vader be really
happy.

  To David Shaw: I didn't get your point, since both defragmenting and
overwriting files involve to be able to control what is written and
where is written... I think both concepts are related somehow. Anyway, I
already got my answer.

  Best Regards
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