I had an odd thing happen to an external hard drive last night and I'm wondering if there are any ideas as to what it might have been. I've been ripping a bunch of my DVDs, going from an external DVD drive connected via USB to a hard drive in one of those toaster-style docks, also connected via USB (both directly connected to different ports on the Mac--no hubs). It's run very smoothly through over 2TB of rips across two hard drives, including in the evenings when I turn off the DVD drive, unmount the hard drive, and power its dock off. Last night, however, after I'd turned off the DVD drive, the external hard drive refused to unmount. What was REALLY weird, though, was that Activity Monitor was showing a constant level of about 32MB/s drive writes (zero drive reads, unless I did something), which I'm pretty sure was entirely to the external--it wasn't seeking, but the dock's access light was on steady, and the speed was around what you'd see maxing out the USB2 bus. At first I thought it was Spotlight acting up trying to index the DVD images on the drive, but there were NO reads, and NOTHING in Activity Monitor was showing more than 2% CPU. I even killed mds to make sure, and it made no difference. When I tried to use Disk Utility to unmount it, Disk Utility froze, and subsequently refused to respond (I could, however, still access stuff on the external). I tried quitting everything open, which didn't change anything, and I even tried to find out what files were being accessed using What's Keeping Me and lsof, neither of which turned up ANYTHING I could find outside the boot drive. I didn't see anything unexpected in the console log, either. Ok... time for a reboot. I logged out of my account, which I was a bit surprised DIDN'T hang, but the access light was STILL on steady from the login screen with no users logged in. I shut down, which was a little slow, but succeeded, at which point the external spun down as expected. Does anybody have any idea what might have been going on there? Ever seen steady phantom drive writes like that?