I did some reading on the subject of secure erase and found very little
except a great example of stupid things PhDs [1] say [2]. Italics by yours
truly. Just wanted to share these gems with you. (Why yes, I'm a cranky old
bastard.)
"It should be noted though that a secure erased drive that is then physically
destroyed would be extremely difficult if not impossible to recover data
from."
"Investigations at CMRR at UCSD have shown that a single pass secure erase at
lower frequencies results in no remaining data signals and a second erase
reduces this signal only slightly more."
1 http://cmrr.ucsd.edu/people/Hughes/
2
http://cmrr.ucsd.edu/people/Hughes/documents/QandAforwebsite10212008_000.doc