and wherein said interface means cooperates with said cache means to implement said hardwired protocol as a snooping coherency protocol which updates said first and second directory means to {HEAD ~ a concurrently valid status condition} via {TAIL ~ non concurrent clock cycles} 
and wherein said interface means cooperates with said cache means to implement said hardwired protocol as a snooping coherency protocol which updates said first and second directory means to { HEAD ~ a concurrently valid status condition } via { TAIL ~ non concurrent clock cycles }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL