A reading method for reading contents information with a laser from an optical disc including a plurality of recording layers includes positioning a focus position of the laser at a first recording layer and reading a first part of the contents information recorded in the first recording layer. If a first link information recorded in the first recording layer is detected, judging whether a first condition is fulfilled or not. If the first condition is fulfilled, positioning the focus position of the laser at a second recording layer and reading a first link destination information recorded in the second recording layer. If the first condition is not fulfilled, reading a second part of the contents information recorded in the first recording layer.

In a multilayer optical disc having information layers conforming to a plurality of different optical disc standards, because the type of each information layer is not recorded in the other information layers, in read and write operations by a compatible optical disc device conforming to a plurality of optical disc standards, every time the information layer being accessed changes, it has been necessary to read the type of the information layer and select a method of generating a tracking error signal adapted to the type of information layer, so access has taken time. In order to solve the above problem, in the optical multilayer disc according to the present invention, having information layers conforming to a plurality of different optical disc standards, in an area in one of the information layers, information about the other information layers is recorded. The time required to access the other information layers can be reduced by using this information to select a tracking error signal generating method.

In a case where (i) a reflectance calculated from a reflected light amount obtained from a longest pit (P1max) or a longest space (S1max) in a first pit row is defined as a first reflectance and (ii) a reflectance calculated from a reflected light amount obtained from a longest pit (P2max) or a longest space (S2max) in the second pit row is defined as a second reflectance, the first pit row is formed such that the first reflectance becomes substantially identical with the second reflectance.

Provided is a technique that reduces the possibility that data will not be recorded due to a shortage of test areas. A test area, in which test writing for laser power control is performed, is set in each recording layer of an optical recording medium having a plurality of recording layers, and information indicating a position of the set test area is recorded on the optical recording medium. Furthermore, recorded information of an optical recording medium is reproduced, the optical recording medium including a plurality of recording layers and in which a test area, in which test writing for laser power control is performed, is set in each of the recording layers and information indicating a position of the set test area is recorded; and the information indicating the position of the test area is acquired.

Provided is an optical information recording medium including: a continuously wobbling groove formed in advance by a CAV or a zone CAV. Information is allowed to be recorded on the groove and a land adjacent to the groove, address information is recorded by modulating the wobble, the address information includes a sync pattern indicating a position of the address information and address data, and the sync pattern includes a plurality of first wobble patterns and a second wobble pattern between the first wobble patterns, and at least part of intervals of the first wobble patterns are set to unequal intervals.

An optical disc including at least three layers of recording layers that each record information in an information track. The recording layer includes: an inner circumferential side region positioned on the inner circumferential side; a data region which is positioned to the outer circumferential side of the inner circumferential side region and records content information; and an outer circumferential side region positioned to the outer circumferential side of the data region. The content information is recorded in the data region of the three or more layers, and a point on an upper layer and a point on a lower layer one layer below the upper layer at which playback switches from content information of the upper layer being played back in an inner circumferential direction to content information of the lower layer, are set to be more to the outside than an innermost circumferential position of the data region.

An information recording medium (10) including a first region (11) in which medium identification information has been recorded, a data region (13), and a second region (12) which is positioned between the first region (11) and the data region (13) and in which control information has been recorded, in which an area of the first region (11) is greater than an area of the second region (12) in size.

In at least one embodiment, an optical data storage tape is provided. The optical data storage tape includes a read/write data area including a plurality of writeable tracks for storing data thereon, each writeable track having a first track width. The optical data storage tape further includes a seam area positioned proximate to the read/write data area. The seam area including a plurality of non-writeable tracks, each non-writeable track including a second track width that is greater than the first track width for each writeable track.

An information recording and playback device includes a recording and playback unit, and a controller. The controller divides a recording area of an optical disk into a first recording area which is at an inner circumference side, and a second recording area which is at an outer circumference side. The controller controls the recording and playback unit such that the unit records or plays back data in the first recording area at a first speed, and records or plays back data in the second recording area at a second speed slower than the first speed. The predetermined radius is set to a boundary between an area in which a control residual exceeds a predetermined reference value when servo control related to focusing and tracking is performed on the recording area of the optical disk, and an area in which the control residual does not exceed the predetermined reference value.

An information recording medium (10) including a first region (11) in which medium identification information has been recorded, a data region (13), and a second region (12) which is positioned between the first region (11) and the data region (13) and in which control information has been recorded, in which an area of the first region (11) is greater than an area of the second region (12) in size.