Patent ID: 7746750

Claim:
A method of recording information on and/or reproducing information from a read-only information storage medium, the read-only information storage medium comprising a user data area comprising a plurality of user data frames, each of the user data frames comprising corresponding sync data of a plurality of sync data; the read-only information storage medium further comprising an additional data area that makes the read-only information storage medium compatible with a recordable information storage medium; the additional data area being located before and/or after the user data area; the additional data area comprising at least two additional data frames; a first one of the at least two additional data frames comprising first sync data; a second one of the at least two additional data frames comprising second sync data; the method comprising: forming and/or detecting the first sync data and the second sync data in the additional data area; wherein: each of the first sync data and the second sync data is different from each of the plurality of sync data of the user data frames; and the first sync data is different from the second sync data.