| 摘要 |
A multi-layer disc medium includes two or more reproducing or recording and reproducing layers. One or more layers have a layer information area portion formed by at least a part of a circular path extending circumferentially of the layer. The circular paths have a center coincident with a center axis of rotation of the disc medium and are at substantially identical radial positions from the center axis of rotation of the disc medium. Layer information capable of identifying a layer concerned is disposed on at least the part of the circular path on the layer. By reading the layer information at an inter-layer transference, verification of an accessed layer can be performed simply and quickly, leading to a simple and quick inter-layer transference.
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