This unit actually uses 40-bit DES as detailed here. Additionally, this system is integrated into this motherboard, but is also available as a IDE "pass-through" device if you will, allowing you to use this technology on any (IDE) system with any OS.

This *does* encrypt the data on the fly, it's not just a physical HD lock. The mention of using DOS's "fdisk" does not imply that this is a M$ only product. The point is that the drive must be re-partitioned once the device is installed, since the original drive presumably is not already DES-40 encrypted. The link posted above in this comment has more information.