In {TAIL ~ a write/read mode}, data is transited from an input/output buffer via the transition circuit to an input of the write amplifier or from {HEAD ~ an output} of the sense amplifier via the transition circuit to an input/output buffer 
In { TAIL ~ a write / read mode } , data is transited from an input / output buffer via the transition circuit to an input of the write amplifier or from { HEAD ~ an output } of the sense amplifier via the transition circuit to an input / output buffer
OTH TAIL TAIL 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 OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH