a disc insertion/discharge mechanism that inserts and discharges a disc at {HEAD ~ a predetermined position} between {TAIL ~ a disc insertion opening} and the disc drive unit; and 
a disc insertion / discharge mechanism that inserts and discharges a disc at { HEAD ~ a predetermined position } between { TAIL ~ a disc insertion opening } and the disc drive unit ; and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH