Sanyo Electric., Ltd.

Sinji Kobayashi

Yoshihisa Suzuki

Sayoko Tanaka

Hiroaki Izumi

A disk medium, an information recording device, and an information reproducing device are provided, which are capable of efficiently recording sub-information such as security data and, if the sub-information is set as the security information, enhancing a security performance. The disk is divided into a plurality of zones in radial directions. A logical zone count in each zone is obtained by dividing a total recordable frame count in each zone by a frame count in a unit logical zone. For example, a logical zone count N1z in a zone i is given by:11where Fzi is the total frame count in the zone i, and F1z is a frame count in the logical zone. However, a value given by the formula (1) is not always an integer depending on the zone, and there might exist a frame (gap region) not used for the logical zone. Accordingly, the security data are recorded in this gap region.

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Gifu, Japan

Sinji Kobayashi