in a second cycle, old data are latched into the read register while {HEAD ~ new data} are latched into the write register, and at {TAIL ~ the same time} a set of the data are sent to the outside data buses and are latched into a read buffer, 
in a second cycle , old data are latched into the read register while { HEAD ~ new data } are latched into the write register , and at { TAIL ~ the same time } a set of the data are sent to the outside data buses and are latched into a read buffer ,
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH