[Leaplist] The DD drive challenge

[Steve Litt]

On Monday 07 April 2008 09:34, patrick wrote:
> Here is a challenge, where a Western Digital 80 GB drive with a folder
> and two files on it is hit with the DD command, and you win if you can
> recover the name of one of the files or the folder.
>
> Purpose is to dispel rumors that a drive need be multiply written with
> zeros to erase all data.  Government agencies and professional drive
> recovery specialists refuse to take this challenge.
>
> Representatives of some who were contacted quoted their engineers that
> they have already proved that recovery after a Unix DD command is
> impossible.
>
> http://16systems.com/zero/index.html

I don't believe it. In the mid 1960's I recorded songs off the radio on a reel 
to reel tape recorder (hope the RIAA doesn't break down my door for that). 
Sometimes I'd record over songs already recorded. When I did, if you listened 
carefully, you could hear the old song. If you listened carefully, you could 
recognize the old song.

Tapes and disk platters have something in common -- they're analog. No matter 
the fact that the content of the disk platter is turned into digital 
content -- on the platter it's magnetically alligned oxide particles (or 
something like that), and those particles don't instantly change their 
alignment as 1 transcends to 0.

Using analog processes, I'm sure it's possible to neutralize the dominant 
encoding in order to "hear" the encoding behind it. Is it easy? No. Can it be 
done digitally? No. Can it be done without taking the drive apart or changing 
the drive? I don't know. But I'm sure given the time and resources (more time 
than 3 days and more money than a drive and $40.00), a lot of data can be 
recovered from a dd'ed drive.
 
SteveT

Steve Litt
Author: Universal Troubleshooting Process books and courseware
http://www.troubleshooters.com/