Hi
I have a multidisks pc, a raid 1 with the system I use and two other disks each one with his OS.
The problem is that if I use one system, the other disks still spining till I shutdown the machine, ®Windows® 8® instead® shut them down if unused (I'm sorry but is true).
Ok that disks needs to be running to be mounted, but once that this si done, if they are really unused as it happens mostly on my system it is greatly better to switch them off or find a way to frezee'em up, reactivating them when they are needed. I think that is better to wait few seconds more to reactivate a shutted down disk that to waste unusefully energy.
My best regards
Fabio