Abstract: A recording medium is provided with: a guide layer on which a guide track or tracks are formed; and a plurality of recording layers, wherein a same mark group is formed in a same rotational phase position of each of a plurality of guide tracks which are included in a beam spot of guide laser light, the mark group including a pair of record marks which are shifted by a predetermined distance toward a right side and a left side, respectively, from a track center.

Abstract: A recording medium is provided with: a guide layer on which a guide track or guide tracks are formed; and recording layers, wherein (i) an information mark group and (ii) a distinctive mark group are formed in the guide layer, the information mark group being formed on each of a plurality of guide tracks, the distinctive mark group distinguishing a center track out of the plurality of guide tracks on each of which the information mark group is formed, the distinctive mark group including a pair of distinctive record marks which are shifted toward a right side and a left side, respectively, from a track center of the center track, a width of each distinctive record mark is twice or more a width of the guide track.

Abstract: A recording medium is provided with: a guide layer on which a guide track or guide tracks are formed; and recording layers, wherein (i) an information mark group and (ii) a distinctive mark group are formed in the guide layer, the information mark group being formed on each of a plurality of guide tracks, the distinctive mark group distinguishing a center track out of the plurality of guide tracks on each of which the information mark group is formed, the distinctive mark group including a pair of distinctive record marks which are shifted toward a right side and a left side, respectively, from a track center of the center track, a width of each distinctive record mark is twice or more a width of the guide track.

Abstract: An information recording medium adopting a zone CAV method is provided with: a guide layer in which tracks are formed in advance; and a plurality of recording layers laminated on the guide layer. On the tracks, a plurality of guide areas, each of which has a physical structure for carrying guide information for guidance, are arranged discretely at arrangement intervals of predetermined distance or less which is set in advance in a track direction and are shifted between a plurality of tracks throughout the plurality of tracks which are adjacent to each other in a radial direction. On the tracks, moreover, a plurality of specific areas, each of which has a predetermined pattern, are respectively arranged in a same phase from an inner circumference to an outer circumference in the radial direction such that the predetermined pattern can be detected in a state in which tracking servo is open.

Abstract: An information recording medium (11) adopting a CLV method is provided with: a guide layer (12) in which tracks (TR) are formed in advance; and a plurality of recording layers (13) laminated on the guide layer. On the tracks, a plurality of guide areas (22), each of which has a physical structure for carrying guide information for guidance, are arranged discretely at arrangement intervals of predetermined distance or less which is set in advance in a track direction and are shifted between a plurality of tracks throughout the plurality of tracks which are adjacent to each other in a radial direction.

Abstract: An information recording medium (11) adopting a zone CAV method is provided with: a guide layer (12) in which tracks (TR) are formed in advance; and a plurality of recording layers (13) laminated on the guide layer. On the tracks, a plurality of guide areas (22), each of which has a physical structure for carrying guide information for guidance, are arranged discretely at arrangement intervals of predetermined distance or less which is set in advance in a track direction and are shifted between a plurality of tracks throughout the plurality of tracks which are adjacent to each other in a radial direction. The plurality of guide areas are disposed in a partial plurality of slots which are not adjacent to each other in the track direction and which are not adjacent to each other throughout the plurality of tracks in the radial direction, out of a plurality of slots obtained by dividing the tracks in the track direction.

Abstract: A check matrix generating method of generating a check matrix (H) for decoding coded modulation data, which is encoded by a low-density parity check code and which is modulated by converting a-bit data (wherein a is a natural number) to b-bit data (wherein b is a natural number) wherein a is a modulation symbol unit, the method provided with: a check matrix generating process of generating the check matrix by determining each element such that the number of elements of 1 is less than or equal to one, out of a elements corresponding to data of the same modulation symbol in each of rows which constitute the check matrix.