On Thu, Sep 30, 2010 at 9:04 AM, Jeremy <jeremy at lizakowski.com> wrote: > There is also the issue of incomplete erasures. Even if you could > wipe every sector, a slight ghost image remains. That's why many > tools offer to rewrite each sector multiple times. But even that > assumes it can move over the magnetic media in exactly the same > position - physical media will always be impefect. This used to be a major issue, but with modern drives the bit density is so high that all available evidence supports a single-pass overwrite being sufficient to completely obscure data from any possible recovery. So unless you're still using a drive from 1988 or something, don't worry about it. - Tony