queueing means for storing data requests to said {TAIL ~ main memory} means by a requesting processor and for storing data to be returned to {HEAD ~ a requesting processor} 
queueing means for storing data requests to said { TAIL ~ main memory } means by a requesting processor and for storing data to be returned to { HEAD ~ a requesting processor }
OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD