Patent ID: 8811137

Claim:
An optical data storage medium comprising: at least one layer, satisfying BD optical disc standard, having a track upon which a laser beam is focused during use; and a management area and a user data area provided on said at least one layer satisfying BD optical disc standard, said management area having recorded data representing if another recording layer of different optical disc standard is present in said medium, and said management area being located interiorly to said user data area, wherein said recorded data has a first information section representing presence and absence of a DVD layer and a second information section representing presence and absence of a CD layer, and when said DVD layer is present in said medium, said first information section represents if said DVD layer is read-only type or recordable type, and when said CD layer is present in said medium, said second information section represents if said CD layer is read-only type or recordable type, said recorded data is provided only on the management area of the layer satisfying BD optical disc standard, said recorded data represents absence of a recording layer by bit values of 00.