I confess, when we reached the disk testing systems, I thought we’d stumbled into a row of blenders in the employee lounge. Alas, drinks would have to wait. These machines measure head-media tribology. Tribology is the science of interacting surfaces in motion, a.k.a. friction. True, the head and media should never come into contact—again, that would constitute a head crash and wreck your drive—but the distance between them is so slight and the media is spinning at such high velocity that the air molecules between the head and platters can become a significant source of friction as they slam between the two solid objects. The tester is programmed to move the head across the disk, monitoring any interactions between the head and disk that could threaten reliability. It can also make a mean margarita with the right USB attachment. OK, no, it can’t.