I think the most simple and logical answer would be “dying,” but this seems a little unusual. I have a Mac Mini with an Iomega external 500gb hard drive. The hard drive is making noise; not the death-clicks indicative of a hard drive on its way out, but the noise you usually hear when it’s reading/writing. But it’s constant. My OS X Activity Monitor shows constant spikes in reads/writes. Movies being played off the drive started skipping in VLC. So I figured it was caused by some rogue software monopolizing the drive.
So I put my Mac to sleep…and the noise continued. I turned the drive off all night & disconnected its firewire cable from the Mac. Turned it on this morning and it’s still making noise. Is there anything built into an external enclosure, or the drive itself, that would cause it to chunk away even without input from the computer?