OPTICAL RECORDING MEDIUM AND OPTICAL RECORDING/ REPRODUCING DEVICE

摘要

PROBLEM TO BE SOLVED: To enable an optical disk to secure the reference position for soft format with a sufficient positional accuracy. SOLUTION: A track 3 provided in the optical disk 52 for the soft format is constituted of pre-grooves 35 and index marks 53 to indicate the reference position of the soft format. The reference position is obtained from the level change of the index marks 53.