Over in the discussion about disk labeling, the blkid tool was mentioned. I ran it (no args), and it showed the label on all my partitions, including the /dev/dvd device, which doesn't have a DVD in it. The label it showed me was the last DVD I did have in it a few days ago, and I've rebooted several times since then. Where the heck is this coming from? Does the DVD drive itself store that? (I probably haven't powered off the system since that DVD was in there, so I suppose the drive might be the one stashing it). Another thing to be paranoid about! The NSA can keep track of which movies you last watched by remotely querying your DVD drives! :-).