Re: More on the Lower Merion school district webcam debacle

[der Mouse <mouse () rodents-montreal org>]

> > Unless that IT dept was bright enough to do low level formats.

> I would dearly love to do computer forensics against someone stupid
> enough to think that a low level format actually erased any
> significant data ...

In my experience, it does.

It is, however, often confused with merely rebuilding the filesystem,
which is _not_ a low level format and does _not_ destroy any
significant amount of data (in most implementations).

A real low level format involves laying down completely new timing
tracks and such, and will destroy all data unless you're willing to
open the drive in a cleanroom and look at residual magnetization
patterns and the like.  It's not always possible; for example, I don't
recall seeing any ATA command for it.  SCSI has the FORMAT UNIT
command, which, if done right, is a real reformat - I don't know
whether modern drives actually do a reformat or not.  (On the few
occasions when I've wanted a real reformat of a SCSI drive, FORMAT UNIT
has, as far as I can tell, done it.)

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