| 摘要 |
PROBLEM TO BE SOLVED: To prevent an unauthorized copying by satisfactorily identifying the unauthorized copying and also to cope with the prevention with a simplified equipment and moreover to maintain compatibility also. SOLUTION: The margin part 20 and the disk management part 22 of a read-in area 12 are respectively constituted of excessive sectors M1, M2 and sectors LI1, LI2. The number of the excessive sectors is set to a very small number of the order of numbers which do not violate a standard and is made to be sectors having two numbers of 'n', 'n+1'. When a disk having this sector constitution is copied with a normal disk recording device, the number of excessive sectors is increased by two and sectors M4, M3, M1, M2 whose numbers are 'n-2', 'n-1', 'n', 'n+1' become excessive sectors. Thus, it is made possible to identify whether a disk is a regular disk or an unorthorized disk from the change of the number of the excessive sectors. |
