Then, user data is recorded in {HEAD ~ a part} of {TAIL ~ the data area} 324 of the second recording layer 302 along a scanning direction 532 to form a partial range used data area 512 
Then , user data is recorded in { HEAD ~ a part } of { TAIL ~ the data area } 324 of the second recording layer 302 along a scanning direction 532 to form a partial range used data area 512
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL 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