Since the achievement of {TAIL ~ coherency} is distributed in time and {HEAD ~ space}, the node controller helps to maintain cache coherency 
Since the achievement of { TAIL ~ coherency } is distributed in time and { HEAD ~ space } , the node controller helps to maintain cache coherency
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH