Originally Posted by
Saab Dastard
And if you want to render the disk truly useless, dismantle it and shred / smash the platters to smithereens, which has the side effect of being rather therapeutic.
But also a heck of a job; I've done it myself a couple of times, and disks are hard to destroy unless you have a sledgehammer handy. If i remember correctly, the approved 'military wipe' specification for the systems a friend worked on in the 90s was a thermite charge, or a full magazine from an M-16.
The best method these days is the one most modern SSDs use; they have an internal encryption key they use to encrypt everything written to the disk. Then they have a 'secure wipe' command which tells the disk to throw away the old encryption key and generate a new one. Any remaining data is completely useless at that point, because you'd have to be able to break 256-bit AES encryption to read it. Wonder if modern hard drives do the same?