On 2/7/14, 8:11 AM, David Brown wrote:

In an experiment, researchers wrote some bits to a sample of hard drive
material, overwrote them once, then tried to read the old data.  I can't
find the reference (I really wish I could)

Overview at:

 http://digital-forensics.sans.org/blog/2009/01/15/overwriting-hard-drive-data/

Detailed article at:

 http://privazer.com/overwriting_hard_drive_data.The_great_controversy.pdf

-- 
Robert L Mathews, Tiger Technologies, http://www.tigertech.net/