I have a USB2+Firewire external disk that made a clicking noise, and Mac OS X immediately unmounted it and put up a dialog box saying that a peripheral is misbehaving. The disk made a clicking noise several times in a short interval, and each time it did, the dialog box on screen would flash. So I unplugged it, waited for a few seconds, and plugged it in to another Mac, and this time it worked perfectly. I copied all 800 GB of data out of the drive over some 9 hours, and it worked perfectly and at its usual speed of 30 - 40 MB/second.
Now that all my data is out of the disk, I repaired the filesystem using Disk Utility. What else should I do? Should I run some kind of disk scan tool that checks the entire disk for bad blocks? Can you suggest a tool for the Mac? Since the disk has a HFS+ partition (and a FAT32 partition), I think I should run a disk repair tool on Mac rather than Linux. Is that correct?
I don't have SMART data since it's an external disk, and I don't want to break open the enclosure.