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