Bootable ISO.

[Tim Seufert]

On Friday, June 27, 2003, at 11:29  AM, Konstantin Riabitsev wrote:

> Hello, all:
>
> A friend of mine, who works for Duke IT Security, was wondering if 
> there is an easy way to create a bootable CD that would do one thing:
>
> cat /dev/zero > /dev/hda
> cat /dev/urandom > /dev/hda

Is it desired that it be automatic?  (That would be a dangerous CD.  :) 
  If not, a quick & easy way to do part of it is an OS X install CD.  
You can launch Disk Utility from one of the menus, and then format a 
disk using the option to zero all data.

I'm not sure that writing data from urandom will do much useful after 
zeroing the disk.  AFAIK, if you want to do the full on tinfoil hat 
thing to prevent data recovery by taking the disk apart and doing 
exotic things to it, you must do considerably more than a single pass, 
and you must guarantee that you flip bits between zero and one 
repeatedly.  You probably even need to use special patterns that are 
tailored to the encoding scheme used by the drive in question.  US 
government types usually don't bother with any of that and simply 
destroy retiring disks by putting them through grinders and then 
burning the pieces.  Saves all the worrying about whether overwriting 
really does the job.

If you're not worried about people taking the disk apart, so far as I 
know, zeroing is adequate.  I'm not aware of any way to recover 
leftover fringes of tracks using the drive's original controller and 
firmware.  (Disclaimer: I am not a security weenie so don't take my 
word on it.)