Darik's Boot and Nuke ('DBAN') is a self-contained boot floppy that securely wipes the hard disks of most computers. DBAN will automatically and completely delete the contents of any hard disk that it can detect, which makes it an appropriate utility for bulk or emergency data destruction.It's a pain to safely discard a hard drive, or a laptop for that matter. It's quite hard to get rid of the data. This open source utility, available for Mac or PC, will do the work. I prefer not to think of what constitutes a need for "emergency" data destruction.