Acknowledging the risk that deleted data might be recovered using “under-data,” the U.S. Department of Defense has a project running with Georgia Tech Research Center to perfect a technique for absolutely ensuring data erasure from a hard disk in less than 5 seconds. Apparently, software based “data shredders” such as Norton WipeInfo don’t do an adequate job. Bad sectors of a hard disks that have been marked for exclusion from new data writes by disk electronics are ignored by the erasure process too. Since some valuable information might persist in these sectors, another approach, dubbed “Guard Dog” by developers, is being tried that leverages a 125-pound magnet and a hand crank to completely obliterate disk data in all sectors.
A 125-pound magnet and a hand crank? Man, I gotta get me one of those!
The rest of the article is well worth reading, too, by the way.