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