there are many ways that an electrical failure of a drive can knock out a computer. think of
what would happen if it shorts out the 5v or 12 power going into the drive for an obvious
in practice it's normally not that bad, but especially fro a SCSI array you don't normally
have a seperate cable for each drive, you have them connected to a bus. if a drive is bad it
can cause the bus to lock up when the drive address is probed.
I would also be interested in the specifics of the hardware, but this sort of failure mode is
not uncommon, and the number of systems that actually implement protection against all of them
is extremely small.