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

[Jussi Lehtola]

On Thu, 2009-06-11 at 10:38 -0600, Robin Laing wrote:
> There was a challenge put out to recover data that was erased with dd 
> but no takers.  The comment that I read on the web site pointed to a 
> phone call that dd makes it to costly to recover.

The title says it all:

http://www.h-online.com/news/Secure-deletion-a-single-overwrite-will-do-it--/112432

A few excerpts: 

"Craig Wright, a forensics expert, claims to have put this legend
finally to rest. He and his colleagues ran a scientific study to take a
close look at hard disks of various makes and different ages,
overwriting their data under controlled conditions and then examining
the magnetic surfaces with a magnetic-force microscope. They presented
their paper at ICISS 2008 and it has been published by Springer AG in
its Lecture Notes in Computer Science series (Craig Wright, Dave
Kleiman, Shyaam Sundhar R. S.: Overwriting Hard Drive Data: The Great
Wiping Controversy)."

"A single bit whose precise location is known can in fact be correctly
reconstructed with 56 per cent probability (in one of the quoted
examples). To recover a byte, however, correct head positioning would
have to be precisely repeated eight times, and the probability of that
is only 0.97 per cent. Recovering anything beyond a single byte is even
less likely."
-- 
Jussi Lehtola
Fedora Project Contributor
jussilehtola at fedoraproject.org