When trying to figure out a way to restrict access to my external FW HD by other users, I restricted MYSELF out of it as well. I've checked the drive via diskutility and it's there, sitting pretty. When I unplug it while OSX is up and running, I even get the warning about unplugging the drive without ejecting it. Is there any way (terminal or not) to find the drive and reset my permissions. Since it's not a "boot up" drive, I can't reset the permissions in disk utility. Bummer.