I have a few external drives, mainly different versions of WD Mybook's (500GB Pro with FW & USB2, 1024GB version with FW, Esata and USB2, 2048GB with USB), and a Buffalo (1024GB FW, USB, E-Sata) which have been attached to a late 2006 iMac C2D with Snow Leopard.
All drives work well with both USB and FW, untill at some point they stop responding. Actually my whole Finder will pretty much jam until I turn the power switch on the disk (get an OSX error for unplugging a disk in an unsafe way but suddenly the computer starts responding again). My assumption is that the drive goes into some kind of power saving and OSX can't wake it up again. The problem is annoying, and makes using a locally attached disk for timemachine backups quite a hassle. I've tested the disks on a Synology NAS and there they seem to work just fine.
Does this sound normal? Would it be a problem with so many disks, or rather the computer it self? Is there any simple solution (I already removed the "put disks to sleep when possible" setting to no avail; this seems to rather be related to putting the computer itself to sleep for so long that the disk goes into hibernation and when the computer wakes up the disk does not).
If there's no elegant solution (and no, a cron script writing to the disk every 10s is not elegant IMO) then what would be a recommended model with FW 800 and USB that would work?