Patent ID: 8837266
Filing Date: 2014-09-16
Classification: G11B

Abstract:
1. An optical data storage medium comprising: at least one recording layer, satisfying BD optical standard, having a track upon which a laser beam is focused during use; and a management area provided on said at least one recording layer satisfying BD optical disc standard, said management area having recorded data representing if another type of recording layer is present in said medium, wherein said recorded data represents if said another type of recording layer is present at a predefined depth of said medium, and said recorded data represents a depth at which said another type of recording layer should be present, and in case that said another type of recording layer is not present in said medium said recorded data indicates that said another type of recording layer is not present at said predefined depth, 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.