Patent ID: 8514681

Claim:
An address detection method for a recording medium having an area for recording a plurality of data and an address indicating a physical recording position corresponding to the data, wherein: virtual bits are used as extension bits of the address; the address is embedded in a wobble; the area has a plurality of recording layers and a plurality of cluster structures; the address is configured by a layer number address indicating numbers of the plurality of the recording layers, a cluster number address indicating a data position of the plurality of the clusters and an in-cluster count value indicating a physical position in the cluster; the virtual bits indicate a switching of a regularity of two low-order bits of the address, and are used as extension bits of the cluster number address; the regularity of two low-order bits indicates whether an increment is repeated in the two low-order bits; the cluster number address is extended by using the virtual bits without changing a number of address bits embedded in the wobble; the virtual bits are generated by detecting the regularity of two low-order bits; and a data position of clusters is detected from the generated virtual bits and the cluster number address.