That's the sound my computer's hard drive started making at about 0300 this morning. Got up to have a piss without realizing I'd heard this sound. Then: clickityclickityclick... clickityTAP! clickityclickityclickityclickityclickityTAP! clickityTAP! Aw, fuck. Had no idea what it was but I was sure it wasn't a goodness. At first, I thought it was something in the computer's fan, but after coming fully awake I remembered that iMacs' air intakes are on the bottom edge of the computer and the openings are as thin as a leftist's rationalizations, so nothing would've fallen into them. So I looked through System Information, every part, and found the culprit. It was the internal hard drive failing. Considering the machine was refurb when I got it almost 4 years ago, I figure it's been a trooper. And it's gonna keep being a trooper, hopefully, for a while longer. I reformatted an external drive, aimed an OS installer at it, then migrated all my shit off the internal drive onto the external, then wiped the internal to keep the computer from mounting it.