19 Apr
2005
19 Apr
'05
12:03 p.m.
My understanding is that one of the specifications for
removing secure
information from a hard disk requires writing zeros to the disk six or
seven times. Norton Utilities (old version) had diskwipe and filewipe
where you could specify how many times to write to the disk.
Some time ago, there was a discussion of how to recover data that had
been overwritten. The only thought I have is that it would take some
specialized equipment to read the disk and would take the hysterisis of
writing to the disk into account. My guess is that the magnetic field
would be such that after six or seven writes, the prior data would no
longer be recoverable.
It is thought that NO amount of reading and writing will completely
scramble a disk. There is a reason why the NSA/CIA/FBI/military
disintegrates their disks.
William Donzelli
aw288 at osfn.org