{TAIL ~ The RA} provides a subsystem with a mechanism for sending read and write requests to the DA of {HEAD ~ another subsystem} 
{ TAIL ~ The RA } provides a subsystem with a mechanism for sending read and write requests to the DA of { HEAD ~ another subsystem }
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD