Patent ID: 8582407

Claim:
An information recording medium, comprising: two recording layers, wherein each of the two recording layers respectively comprises a compatibility information area storing compatibility information; a user data area; and a lead-in area comprising the compatibility information area and a defect management area separate from the compatibility information area, the defect management area configured to store information on replacement data for replacing defective data in the user data area and comprising a write protection flag; and the compatibility information area configured to store information for performing a predetermined function, and compatibility information for a recording and/or reproducing apparatus which does not recognize the predetermined function, the compatibility information comprising information regarding a basic recording and/or reproducing function specifying whether each area of a plurality of areas on the information recording medium is recordable and/or reproducible, the information regarding the basic recording and/or reproducing function comprising: information specifying whether a user data area on the information recording medium is recordable and/or reproducible; information specifying whether the defect management area on the information recording medium is recordable and/or reproducible; and information specifying whether the compatibility information area on the information recording medium is recordable and/or reproducible; wherein even if the compatibility information read from the compatibility information area indicates that the user data area of the information recording medium is recordable, the user data area is write protected in a case where the write protection information read from the defect management area indicates that recording data on the information recording medium is prohibited or write protection information of a cartridge containing the information recording medium indicates write protected, and wherein if the compatibility information read from the compatibility information area indicates that the user data area of the information recording medium is recordable, the user data area is not write protected in a case where the write protection information read from the defect management area indicates that recording data on the information recording medium is not prohibited and the write protection information of the cartridge containing the information recording medium does not indicate write protected.