[mdlug] Erase hard drive

[Michael Rudas]

R. Kannan wrote:

> I was looking at this article and it says that
> 'newer, more advanced, techniques make it possible
> to retrieve data that was replaced with a bunch of 0s after issuing the
> command
> How is it possible to 'read' data that has been replaced with zeros?

Though we normally treat a hard drive as a digital device, it is
ACTUALLY an analog device with a digital interface.  Even if the HD
platter surface has been overwritten with a magnetic pattern by the
drive's circuitry, due to its analog magnetic nature it's possible to
"peel back" recorded layers up to 3 deep using forensic-analysis
custom (for each drive) electronics and techniques-- which is why
secure drive-wiping programs usually do at least five (usually eight)
random overwrites per sector.

A facility I worked for was once fined about $20,000 for improper
disposal of a broken government hard drive, so this stuff IS taken
seriously...

-- Mikey