>>>> "Gordon" == Gordon JC Pearce
<gordonjcp at gjcp.net> writes:
Gordon> After the disk has been overwritten *once*, the data can not
Gordon> be recovered without extremely specialised tools. Write a
Gordon> suitably random pattern over the whole disk a couple of
Gordon> times, and it is gone. Utterly gone. No amount of prodding
Gordon> with electron microscopes will bring it back.
There is an excellent article on this whole subject by Simson
Garfinkel -- I don't remember the title or publication. He described
collecting a bunch of secondhand PCs and investigating what was left
on them, and discussed various cleanup tools and how well they defend
against attempts to recover data.
If a decisionmaking person is worried about this issue but interested
in hard facts, that article may be helpful to provide those facts.
paul