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Re: OT: Can Reformatting A Hard Drive To ext3 Destroy All the Data On It?





Robert L Cochran wrote:
I have a hard drive that I need to destroy the data on. What is the most
dependable way to do this? Can reformatting the drive as ext3 or ext4 or
some other filesystem effectively destroy the existing data?

Is there free software that can write zeroes or some form of nonsense to
every storage location?


Overwriting the disc, even several times, is not enough to guarantee
that the data _cannot_ be recovered. If you truly need to make the
data unrecoverable, then a hammer is all that's needed. To be truly
sure, open the case (also requires a screwdriver or nutdriver),
and shatter each disc separately. They are usually ceramic these
days, I think. Anyway, physical destruction is the only real guarantee.

Mike

Much depends on how "destroyed" your data needs to be.  You can certainly
write zeros to a drive

dd if=/dev/zero of=/dev/hda #or whatever device is your drive

does the trick.  But if you have any special partitions for diagnostics, a
"recovery image", or you just have some space on the drive that can't be
reached  then this won't really destroy everything.  Some drives have
reserved areas that aren't accessible through normal OS means.

There are programs like Darik's Boot and Nuke (dban.org) that claim to
destroy data by various means.  I don't know if they can clean
manufacturer's reserved areas on the drive.

If you have very sensitive data, then as Mike posted, shatter the drive.
Break it so that no piece of the disk is larger than one disk sector,
otherwise a piece might have a cleanly recoverable chunk of data on it.

This link might help:
http://www.stanford.edu/group/security/securecomputing/data_destruction_guidelines.html

I know that there are a number of commercial services that offer to destroy
disks, recycle what can be recovered, and provide you evidence of "observed
destruction", although I don't have much experience with them.

Erik



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