In the interests if keeping some data off my laptop's main drive but still accessible, I bought a Firewire/IEEE-1394 hard drive enclosure and stuck a 120gb drive in it. Well, tonight when I plugged it in the drive, after having it roaming the house for the day, the drive wasn't identified by OSX - the drive was on, I could hear it purring away, but it wasn't actually doing anything. As it turns out, the enclosure is controlled by the Prolific PL3507 chipset that has reliability problems, which sucks.