Abstract: A data library apparatus capable of changing the mounting positions of disks on the basis of information recorded in the disks and the access histories of the disks. Disks expected to be accessed next are mounted in advance on data recording/reproducing devices, on slots nearer to the data recording/reproducing devices, or on a disk carrying device, etc. In addition, disks relevant to currently active disks are mounted on positions so that the optical disk carrying device can bring out the relevant disks at a time without being moved, and hereby the time necessary for disk access in the data library apparatus can be reduced.

Abstract: A display device includes a first interface, a second interface and a display circuit. The display device transmits a first connection confirmation signal to confirm connection, via the first interface to a playback device and receives a response signal in reply to the first connection confirmation signal, transmits a second connection confirmation signal to confirm connection, via the second interface to the playback device and receives a response signal in reply to the second connection confirmation signal, and makes a function to use the first and second interfaces between the display device and the playback device available if both response signals in reply to the first and second connection confirmation signals are received.

Abstract: In a recording medium, an extension address is obtained without changing the number of bits of the address embedded in the wobble. The wobble address is partially or wholly encoded to embed the address information. At the time of reproducing the address information, the original address information is obtained by restoring the embedded information by the decoding process.