Optical disk medium and method and apparatus for reading information

摘要

An optical disk medium which comprises a track groove thereon and on which information is recorded along the track grove on a block unit basis, the block unit having a predetermined length, wherein the block unit includes a number of subblocks that are arranged along the groove, wherein a sub-block mark is provided wobbling in a sine wave curve within each said sub-block and used to identify the sub-block, and wherein a part of the track groove has a sawtooth-like wobble shape that is defined by a combination of a steep displacement pattern and a gentle displacement pattern to represent address information of the block unit. <IMAGE>