Combination type optical disk medium, its reproduction method and optical disk apparatus

摘要

A combination type optical disk medium and recording or reproducing method in which the medium include first and second recording layers based on different recoding densities. First and second volume spaces are formed to the first and second recording layers, respectively. Each volume space includes identification information of a head or end of the volume space, and an area for data. One of the volume spaces is recorded with identification information of the other volume space.