Clearing the unallocated disk space

[Bruno Wolff III]

>>> On Sun, Nov 16, 2014 at 2:04 PM, jd1008 <jd1008 at gmail.com
>>> <mailto:jd1008 at gmail.com>> wrote:
>>>
>>> Before sending the drive for warranty service, what is the best
>>> way to clean the unallocated blocks?

If this is really important to you, just eat the cost of the drive and 
destroy it instead of sending it back.

If not modern drives provide a secure erase function and you should use 
that. You can use hdparm to do this.