There are dozens of ways to share drives, just not this one... I was hoping firewire was more evolved. sure, you can't actually physically write to disk from to pc's at the same time. But I hoped you could still connect the devices, and let firewire take care of the rest.
Seems this can't be done. I was able to actually perform reads and writes, but the eventually got a "write behind delay" error. this was true even with just searching one drive while just reading from the other - not writing anything to disk. still true after disabling write behind caching (or maybe you have to enable that instead?). Either way, I could push on it, and get the error.
Seems like a bad idea to keep trying. I think different chipsets give you some different behavior as well, but it's pretty clear you can't count on connecting pc's and drives up in this manner.