Never knew about this, but we can lock in the level of hard drive!

As I work in a computer company, there are RMAs.. (Return merchandise authorization) and some of them has harddrive locks in them.

As I ‘ve never seen them before, I was really interested in them, and even found out about linux and setting harddrive states. We can use hdparm to set states!

http://www.admin-magazine.com/Archive/2014/19/Using-the-ATA-security-features-of-modern-hard-disks-and-SSDs