Optical disc and optical disc device
In a multilayer optical disc having information layers conforming to a plurality of different optical disc standards, because the type of each information layer is not recorded in the other information layers, every time the information layer being accessed changes, it has been necessary to read the type of the information layer and select a method of generating a tracking error signal adapted to the type of information layer, so access has taken time. In order to solve the above problem, in the optical multilayer disc according to the present invention, having information layers conforming to a plurality of different optical disc standards, in an area in one of the information layers, information about the other information layers is recorded. The time required to access the other information layers can be reduced by using this information to select a tracking error signal generating method.
1. An optical data storage medium comprising;
at least one recording layer having a track upon which a laser beam is focused during use; and
a management area provided on said at least one recording layer, said management area having recorded data representing if another recording layer of different optical disc standard is present in said medium,
wherein said recorded data has a first information section representing presence and absence of a first recording layer having first optical disc standard and a second information section representing presence and absence of a second recording layer having second optical disc standard, and
when said first recording layer is present in said medium, said first information section represents if said first recording layer is read-only type or recordable type, and
when said second recording layer is present in said medium, said second information section represents if said second recording layer is read-only type or recordable type.
2. An optical data storage system which receives an optical storage medium according to claim 1 , said storage system accessing said management area to read said recorded data to identify if another recording layer of different optical disc standard is present in said medium.