Space gobbled

[dnanian]

I'm going to guess that your drive failed pretty badly during the copy. It "fell off the bus" during the copy.

Since a drive looks like a folder on OS X, and the OS didn't tell us anything had gone wrong, we kept copying.

To recover the space, disconnect the FireWire drive. Then, use Finder's Go | Go To Folder... menu to open /Volumes.

Once that's done, look for a folder named the same as the (now disconnected) FireWire drive. If you find it, look inside and see if there are files in it (I'm guessing there are). If so, go back to /Volumes and delete that whole folder, then empty your trash.

Once that's done, try your backup again, but make sure your FireWire bus is as simple as possible: no iSight or anything else connected, just the drive. Hopefully, that will prevent any repeat of the failure during your backup.

Hope that helps!