On Sun, Sep 28, 2008 at 11:58 AM, Leo Mauler webgiant@yahoo.com wrote:
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Reformatting a ReiserFS filesystem can sometimes result in data files from the previous contents reappearing on the now allegedly-wiped hard drive, a detail which folks interested in tax breaks for donating old machines, while simultaneously protecting their corporate secrets, would be dismayed to learn.
Anyone who thinks that "reformatting a filesystem" is the same thing as "wiping a hard drive" doesn't understand the meanings of the words "reformatting", "wiping", or "filesystem' for that matter.
You can reformat an ext*, FAT or NTFS filesystem, but if you think you've "wiped" the filesystem, much less the drive, you are wrong beyond description. I can understand a non-technical user not understanding the distinction between "reformatting' and "wiping", but anyone working for a corporate IT department who can't tell them apart should be fired for incompetence.
If I'm asked to "wipe" someone's drive, I'll boot to a live CD or USB drive, get to a root prompt, and do something like
export pass=1 while [ $pass -lt 6 ] do printf '\nDrive Wipe Pass #%d' $pass dd if=/dev/random of=/dev/hda printf ' . ' dd if=/dev/zero of=/dev/hda printf ' . ' pass=`expr $pass + 1` done; printf '\nDONE. You may now turn off the computer'
This is not a theoretical exercise for me. I had a customer who was retiring, and wanted to be sure all data was removed from the server before it was delivered to the buyer. Since it was SCO OpenServer, instead of /dev/random, I used an outer loop of 3 passes with an inner loop that used /dev/byte/55, /dev/byte/ff, /dev/byte/aa, and /dev/byte/00 (after first creating the device nodes for 55 and aa), so that the entire HD was written to a dozen times, with the different patterns. At that point, I figured that there were maybe some guys at Langley (and their Russian and Chinese counterparts) who would have even a chance of recovering data from that drive.
I never referred to that operation as "(re)formatting".