To implement a RAID 1 transaction, an initiator sends a single command, i.e.,
either a single read command, or a single write command, over a common I/O bus
to a primary target device. A mirror target device snoops the common I/O bus and
upon detecting the single command directed to the primary target device, effectively
performs in the same manner as if the command had been directed to the mirror target
device. Hence, a single command is used to effectuate a mirrored transaction.