Firewire drives may lose data under 10.3
Mac OS X 10.3 through Mac OS X 10.3.6 (Panther) may lose data on firewire hard drives. Apple updated the Firewire drivers when creating Panther, resulting in the need of hard drive manufacturers to update the firmware of the cases that have the bridge between IDE and Firewire. This affects:
Oxford 911, Oxford 922, Firewire 400 (IEEE 1394, now has been renamed IEEE 1394a), and Firewire 800 (IEEE 1394b).
Users have reported problems also with target disk mode as well.
The problem occurs if the drive is connected to the computer during restart, shutdown, or a sleep that can't wake which forces a restart, and startup. As a result it is recommended that you dismount the drive before doing any of the above processes, and disconnect the cable to the computer or drive that allows for the Firewire connection after dismounting the drive. To dismount the drive, drag its icon to the trash in the Dock, or if you have the sidebar open, click on the triangle to its right in the sidebar to make it disappear. This means you can't boot off a Firewire hard drive affected by this issue as it would require the drive be connected during startup and shutdown. Only reconnect the drive after the machine has successfully started up and shows the desktop and menubar.
The "Important Note" on 10.3.1 through 10.3.6 update pages say it is only partially resolved:
Apple has identified an issue with external FireWire hard drives using the Oxford 922 bridge chip-set with firmware version 1.02 that can result in the loss of data stored on the disk drive. Even with the improvements available in this update, Apple recommends you update the firmware on your FireWire drive. Please contact your drive manufacturer for more information.
The vendors list is now on http://www.macmaps.com/firewirebug2.html
Initio has found a very similar bug and resolved it with a new firmware update. It may be related:
The Initio readme explains the reason the bug happens in 10.3.6.
If you find other drives are not compatible, please post feedback to the drive manufacturer,
Oxford Semiconductor, and Apple's Mac OS X feedback page with the information about the speed of the Firewire, bridge info if you have it, and maker and model of the drive in question.
If a firmware update is not available for your drive case, you can assume that it is susceptable to the bug in question, and you have to go through the procedure above of dismounting and disconnecting prior to shutdown, restart, sleep, and remounting after successful boot.
Additional notes on mirror.