{TAIL ~ Other circuitry} is coupled to system bus 12 such as {HEAD ~ memory} 17 
{ TAIL ~ Other circuitry } is coupled to system bus 12 such as { HEAD ~ memory } 17
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH