On 24 April 2018 at 05:57, Dave Horsfall <dave(a)horsfall.org> wrote:
[...]
A well-known question in the security field, for
instance, is how do you
know that you have *really* erased that disk? The thing can lie as much as
it likes, and you'll never know for sure.
That reminds of an old mil-spec that told you how to dispose of
disc-packs by grinding down the platters by hand, what grit of paper
to use, which directions, and how often. (Exact number escapes me.)
N.