A data-storage system comprises a head receiver configured to variably receive up to a number M of write heads. The data-storage system also includes an installed number N of write heads arranged in the head receiver, a substrate receiver configured to receive one or more data-storage substrates, and a positioner machine configured to adjust a relative placement of each of the M write heads with respect to at least one of the one or more data-storage substrates.

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 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.

An optical information storage medium includes a substrate and a multilayer polymeric film. The multilayer polymeric film has a first surface and an opposite second surface that extend the length of the multilayer polymeric film. The second surface is adhered to a surface of the substrate. The multilayer polymeric film includes a plurality of coextruded alternating polymeric active data storage layers and polymeric buffer layers.

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.

An optical information storage medium includes a multilayer film that includes a plurality of extruded alternating active data storage layers and buffer layers, which separate the active data storage layers. The active data storage layers and buffer layers have thicknesses that allow the active data storage layers to be writable by non-linear or threshold writing processes to define data voxels within the active data storage layers that are readable by an optical reading device.

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.

A method of writing data to a transparent substrate comprises forming a first voxel by focusing a first laser pulse on a first location in a transparent substrate; and forming a second voxel by focusing a second laser pulse on a second location in the transparent substrate. The first laser pulse and the second laser pulse have different amplitudes, resulting in the first and second voxels having different strengths. Also provided are a system useful for implementing the method; an optical data storage medium obtainable by the method; and a method of reading data from the optical data storage medium.

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.

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.