For example, the UP 503 may interrupt {HEAD ~ the current data stream} and move backwards or forwards in the TM 507 by accessing previous or subsequent data in {TAIL ~ response} to a RW command or a FF command, respectively 
For example , the UP 503 may interrupt { HEAD ~ the current data stream } and move backwards or forwards in the TM 507 by accessing previous or subsequent data in { TAIL ~ response } to a RW command or a FF command , respectively
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH