My previous job was at a state university. Before sending our old computers off to auction, we had to wipe all hard drives according to Department of Defense 5220-22.M standards. This was to ensure the next owner would not be able to recover any sensitive files that were stored on the computer even through forensic analysis. Now I would like to show you how to wipe a hard drive following this same technique.
To wipe a hard drive according to DoD 5220-22.M standards, you need to download a free utility called DBAN. This utility will work on all Windows and Unix file systems. For Macs, you can download a different version here.
Once you have downloaded the DBAN ISO file, you can burn it to either a CD or DVD. Place it in the computer that you want to wipe and reboot. Make sure that the computer is set to boot from the drive that you are trying to run DBAN from.
Once the computer boots into DBAN, you will be presented with a boot prompt. Hit enter to start DBAN in interactive mode.
Once you are in interactive mode, you can choose the wipe method by hitting the M key. The default method is DoD Short which should be fine. You can select the drives and partitions you want to wipe by using your spacebar. Hit F10 to start the wipe.
Depending on your drive size, the wipe could take a couple of hours. Once it has finished then the drive is safe to dispose of.
If you have had experience with DBAN or any other disk wiping utilities please feel free to share.