i want sell my hdd to someone, how would i go about making sure that all date is erased and that it cannot be recovered?

http://dban.sourceforge.net/

Make sure to do several passes if you're that paranoid. Usually, 2-3 will do the trick.

The HDD manufacturer always has some kind of zero-fill utility.

This is the supreme cleaner. It erase everything including partitions and boot sectors.

I use it once a year for a deep clean. Then i start from scrach.

http://dban.sourceforge.net/

Make sure to do several passes if you're that paranoid. Usually, 2-3 will do the trick.

i found that one while googling, i'll give it a try, thanks.

The HDD manufacturer always has some kind of zero-fill utility.

This is the supreme cleaner. It erase everything including partitions and boot sectors.

I use it once a year for a deep clean. Then i start from scrach.

actually this is not the "ultimate" it only writes zeros to every sector. The best way would be to write zeros then ones, then a random pattern to the entire drive. Which by the way is what DBAN will do. multiple times if desired.

You could try SecureErase , it uses the builtin commands in the drive.

@All

FYI, I recently had the confirmation of my long time suspect that the "several passes" are only wasted time; even the man who began it all, Mr. Peter Guttmann, admits as much in his "revised edition" paper:

http://www.forensicfocus.com/index.php?nam...opic&t=2065

The "revised edition" can be found here:

http://www.cs.auckland.ac.nz/~pgut001/pubs/secure_del.html

And here is an excerpt from it, the "Epilogue" (i.e. the newly added part):

Epilogue

In the time since this paper was published, some people have treated the 35-pass overwrite technique described in it more as a kind of voodoo incantation to banish evil spirits than the result of a technical analysis of drive encoding techniques. As a result, they advocate applying the voodoo to PRML and EPRML drives even though it will have no more effect than a simple scrubbing with random data. In fact performing the full 35-pass overwrite is pointless for any drive since it targets a blend of scenarios involving all types of (normally-used) encoding technology, which covers everything back to 30+-year-old MFM methods (if you don't understand that statement, re-read the paper). If you're using a drive which uses encoding technology X, you only need to perform the passes specific to X, and you never need to perform all 35 passes. For any modern PRML/EPRML drive, a few passes of random scrubbing is the best you can do. As the paper says, "A good scrubbing with random data will do about as well as can be expected". This was true in 1996, and is still true now.

Looking at this from the other point of view, with the ever-increasing data density on disk platters and a corresponding reduction in feature size and use of exotic techniques to record data on the medium, it's unlikely that anything can be recovered from any recent drive except perhaps a single level via basic error-cancelling techniques. In particular the drives in use at the time that this paper was originally written have mostly fallen out of use, so the methods that applied specifically to the older, lower-density technology don't apply any more. Conversely, with modern high-density drives, even if you've got 10KB of sensitive data on a drive and can't erase it with 100% certainty, the chances of an adversary being able to find the erased traces of that 10KB in 80GB of other erased traces are close to zero.

(emphasis is mine)

jaclaz