how to sweep hard disk of confidential data
I am in a situation where a computer is to be given away and prior to
that it's hard disk needs to *thoroughly* cleaned (data consists of
financial information, reports, class exams, competition exams, etc).
One method I have found on google is:
$>dd if=/dev/zero of=/dev/hda
to clean the first disk. Now this only writes data once. I am not sure
about this method's thoroughness since I have read that multiple writes
are necessary to really overwrite the original data.
The second method that I have read is to delete everything from the disk
and then write a large file (how to get his? random data?) repeatedly
and fill the disk. Then remove these files with 'wipe'.
Any suggestions? Or any alternate methods? Then there is also the option
of using a Windows programs to do this. But I am familiar with those.