Scrub free disk blocks

JD jd1008 at
Sun Aug 29 00:50:16 UTC 2010

  On 08/28/2010 05:32 PM, James McKenzie wrote:
> Steven Stern wrote:
>> On 08/27/2010 11:25 PM, JD wrote:
>>>    Is there a Linux util to scrub free disk blocks and keep everything
>>> else intact ??
>> This really is an interested thread... but why do you want to scrub free
>> blocks?
>> I can think of a few reasons:
>> 1) You're running Linux in a virtual machine. Zeroing all free space
>> makes it easier to compress the image file.
>> 2) You've been looking at something "bad" and want to make sure all
>> traces of it are gone before the lawyers/cops arrive.
>> There are probably other good reasons, but I'm stalled out here.
> One thing is that if you expect the police on your doorstop, you are
> screwed anyway.  There is NO truly secure method, other than complete
> pulverization, to destroy disk data.
> If you want to clear the free space and reuse it, then the methods
> described are sufficient.
> James McKenzie
> SSCP 367830
> (Yes, I could give a real technical description of why but it involves a
> bunch of phyics and electrical stuff that usually drives folks nuts,
> suffice it that Data Discovery and Restore of Tucson can do what I
> describe to a hard drive that was trown into a fire and the heads were
> melted to the disk.  The police got what they wanted, the disk had child
> porn on it and had been 'secure erased' as well.)
It seems that at least 2 individuals on this list have made the assumption
that hiding data, encrypting data and erasing data is for the purpose of
hiding criminal activity. Such an assumption would put hundreds
of millions of people, and possibly a lot more,  within these two 
category of criminals or highly suspected of criminal activity.

Here we are in the 21st century and we still discover that there are
people with such narrow minds, that they can easily pass through a
1 picometer wide slot.
I am being very generous with that slot width.

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