Jereon also held a presentation on this topic at OHM 2013. I wasn't there, so I cannot wait to see the video recording to show up on the OHM2013 web site. If, like me, you are, deep in your heart, a reverse engineer, this article is a must-read for you. It shows how with a little bit of hardware tweaking, but mostly systematic and logical thinking and debugging, hard disks can be hacked so that they will present fake contents to users - which is a very troublesome thought to anyone concerned about security.
In one of those startling coincidences, just before I found Jereon's article, I dug up old 8085 programming manuals at home. 8085 CPUs were used way in the controller hardware used for Atari's SH20x and Megafile hard disks (I specialized into Atari hardware in the 80s and early 80s). My plan back then was to learn enough about 8085 assembler and architecture so that I'd be able to disassemble and reverse-engineer the controller's firmware. That project never got too far, unfortunately, and so I am really happy to see that a new generation of coders is fascinated by the same idea and, unlike me, follows through. Bravo!