| 摘要 |
PROBLEM TO BE SOLVED: To read target information quickly and correctly by providing a part extending toward the direction of a one side of end parts from a position of a virtual plane, and recording a sync-pattern and track information toward the direction of the other side of end parts from one side of end parts in an ID part in order. SOLUTION: A left sync-pattern 16a for pulling synchronism when information is react from left to right and left track information 17a indicating the track are recorded in an ID part 14a, and a right sync-pattern 16b for pulling synchronism when information is read right to left and a right track information 175 indicating the track are recorded in an ID part 14b. By using an optical card 11 constituted like this, seek operation can be performed in the both direction of reciprocation, a seek time can be shortened to the half approximately, reading can be performed by the other side of the ID part even when reading cannot be performed by one side of the ID part. |
