My Pismo 400 isn't always consistent in mounting my external FW drive. I switched cables, but I still get the inconsistency. I will usually have to reboot with the drive on and plugged in. Could it be that my FW ports are on their way out? It does this in both OS9 and Panther.
My Pismo 400 does the same thing, but I blame it on the firewire/IDE bridge in my Maxtor 80 Gig external.It works fine under 9, but OSX must communicate differently. I have to cut the power on the drive and remove the cable and then power up again. It hasn't happened since Panther, so maybe they fixed it.
I don't see why it would be your port if it is infrequent and restarting solves it. That usually indicates a software loss.
Still, you need to say what OS, what drive, etc. you are using to make a better guess.
Last night I couldn't get it to mount until I switched the cable around a few times to a different port. If the drive doesn't mount, do you need to power it down before removing the cable? I usually just remove it and plug it back in until the drive mounts. I'm operating Panther now, and my external drive is an IBM 60 gig I put in an Oxford 911 enclosure from OWC.
No, it isn't software. It's the bridge. External firewire drives use a bridge to get firewire to IDE. It isn't 100% plug and play and is a combination of firmware and OS.
Different machines will act differently. Plus a disk utility wouldn't fix a firewire port anyway. Firewire is built into the ROM, that is why you can boot from an external FW drive.