wipe /dev/sda

[Joep L. Blom]

Kent Borg wrote:
> Neil Aggarwal wrote :
>>> The best way is to use a reasonably strong electromagnet and sweep it 
>>> over the disk. In the old days we did it to wipe magnetic 
>>> tapes.
>>>     
>> Would that work for hard drives? 
> 
> Kinda. Depends on how strong the magnet is. Basically a bad idea...
> 
> If, after wiping it your computer can't access it, then you are safe
> from casual data retrievers. But you will also have destroyed the disk
> making it unsuited for sale on Ebay. For quite a few years now disk
> tracks have been made so small that the only way the disk can find them
> is by reading markers recorded on the disk itself. Bulk erase and you
> will damage those markers, making the disk worthless as a functioning disk.
> 
> If your magnet makes the disk no longer function, then you have
> prevented the casual disk retrieval attempts.
> 
> If you are worried about a motivated foe, then you won't know. How
> strong is the magnet? How close did you get it to each platter face?
> Just because the disk quits working tell you nothing about whether fancy
> techniques might recover data.
> 
> If you want to destroy a disk, dismantle it, put a strong magnet against
> each platter face for the fun of it (much more effective close than at
> even a slight distance), but then scrape off all the magnetic coating to
> be sure.
> 
> 
> -kb
> 
> 
Well, sure it's radical. However, after wiping with a - not too strong - 
magnet, you only have to do a low-level format. Not so difficult as all 
disk companies has the software on their sites (OK, it's Windows 
software, but people buying old hardware on e-bay will use that).
Joep