FIG 3 is a timing diagram of {HEAD ~ an operation} of {TAIL ~ the controller} 140 
of
FIG 3 is a timing diagram of { HEAD ~ an operation } of { TAIL ~ the controller } 140
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH