Patent ID: 8411538

Claim:
A rewritable and readable optical information storage medium comprising: a plurality of information recording layers each including a recording mark having a length shorter than an optical system resolution limit, wherein: one of the plurality of information recording layers that is closest to a reproduction-laser-incident surface of the rewritable and readable optical information storage medium is capable of being read with a reproduction laser having power lower than that of a reproduction laser for reading another one of the plurality of information recording layers that is farthest from the reproduction-laser-incident surface, and the plurality of information recording layers includes at least one information recording layer in which setting information of reproduction laser power for each of the plurality of information recording layers, the setting information being intended for setting the reproduction laser power for reading the information recording layer that is closest to the reproduction-laser-incident surface to be not less than 1.0 mW but less than 1.1 mW, is stored.