Patent ID: 7684303

Claim:
A read-only optical recording medium adopting a logical format for managing data with an error correction block including a predetermined amount of information and an error correction code for the information in the predetermined amount and a physical format for forming lands and pits on a recording track correspondingly to a modulated bit string generated by making a predetermined modulation of an information bit row, wherein a postscript area having a predetermined postscript pattern formed therein is provided in a plurality of predetermined positions on the recording track, the postscript pattern formed in the postscript area takes the form of a pit-land-pit pattern, modulated bit strings before and after the pit-land-pit postscript pattern are formed so that the entire modulated bit string complies with the rule of a variable-length modulation even when it is replaced as a whole with a pit-only pattern, the land in the middle of the pit-land-pit postscript pattern is formed not to be physically changed when irradiated with laser light having a reading-level power but will show a reflectivity equal to that of a pit when irradiated with laser light having a power higher than the reading-level power, and the number of the postscript areas provided in one error correction block is within such a range that even if all the information bit strings resulted from modulation of the postscript pattern portion are erroneous, the error will be canceled by the error correction code.