means for conveying {TAIL ~ data} to said {HEAD ~ input means} for storage and for receiving stored data from said output means during read/write operations 
means for conveying { TAIL ~ data } to said { HEAD ~ input means } for storage and for receiving stored data from said output means during read / write operations
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH