Symptom #1: Disconnected FireWire Drive Doesn't Mount
"I accidentally disconnected my FireWire drive or knocked its cable loose while the drive was mounted. Now the Mac OS tells me the disk is unreadable or it doesn't mount on the Desktop."
As stated earlier, FireWire drives are just like any other drives in your system. When you want to remove a FireWire drive from the Macintosh, you have to inform the Mac that you are doing so, just as you do with any other type of drive. This may be news to those who are migrating from a PC environment and are used to yanking drives off the system at will. With the Macintosh, you have to dismount any drive that you want to remove. Doing so is easy; just drag the FireWire drive to the Trash, or Ctrl-click the drive and choose Eject name of the drive.
If a drive becomes disconnected improperly, you may see a brief dialog informing you that a FireWire device isn't responding or has been removed improperly. Whenever this happens, stop immediately, shut down your Macintosh, and power down any drives. When your entire system has been shut down, remove and reseat any FireWire cables; then restart your system.
In most cases, your FireWire drives will reappear promptly; Mac OS Extended formatting is pretty resilient. But if the drive doesn't show up, you quite probably have incurred severe directory damage to the drive. Open System Profiler (in the Utilities folder) to check that the FireWire drive is actually present and recognized by your Macintosh. If it is not, the drive may have suffered physical damagea subject to be discussed subsequently. If the device shows up, however, you can attempt to repair the drive's directory structure.
If you are lucky, the drive will also appear in the left sidebar of the window when you open Disk Utility, Mac OS X's formatting and disk-repair utility. Depending on how badly the disk was damaged, you may or may not see the formatted partition grayed out underneath the drive. If you see the drive at all, select it and click Repair Disk in the bottom-right corner of the window.
Again, if you are lucky, Disk Utility may be able to fix and remount the volume. In many cases, if Disk Utility can actually see the disk, it can perform the repair. Unfortunately, sometimes the first data that gets corrupted is the drive's initialized information. When the drive's data is unreadable, Disk Utility won't be able to repair the drive's directories.
If the drive did not appear in Disk Utility, try using a third-party disk utility like Alsoft's Disk Warrior (www.alsoft.com/diskwarrior) to ferret out the real data from corrupted volumes and bring volumes back from the dead. The important thing is to purchase Disk Warrior or an application like it before a problem like this occurs that so you aren't stuck with a dead drive at 11 on a Friday night for a Saturday tape delivery.
Symptom #2: FireWire Drive Doesn't Mount Despite Correct Connection
"My FireWire drive doesn't appear on the Desktop, though it's powered up and appears to be connected correctly."
FireWire's 6-pin connector carries an active electrical circuit called bus-power. Bus-power can deliver electricity to some low-demand devices like 2.5-inch mini-FireWire drives, iPods, and the like so that you don't have to use an external power supply for the device.
The problem is that with cheaper cables and FireWire bridges, there is the risk of having this hot pin short out and fry your driveand potentially even your Macintosh's FireWire ports.
If the drive doesn't show up in System Profiler, you need to shut your computer down again, disconnect the drive from the Macintosh, and examine the cables and the drive's FireWire port.
Also, remember that the FireWire 400 standard limits cable lengths to 14 feet. Although you're unlikely to find FireWire 400 cables longer than that, they do exist. If you notice an inordinately long FireWire cable, particularly in environments with a lot of heavy-duty electrical devices like speakers and production monitors, think about switching the cable out with more reasonable lengths, or invest in a FireWire cable extender to boost signal integrity and strength.