| 摘要 |
PROBLEM TO BE SOLVED: To secure instant responsiveness to access by suppressing the excessive drop of a recording speed at a disk inner circumferential side part and further suppressing the difference in rotational speeds between the inner circumferential side part and the outer circumferential side part. SOLUTION: At the time of access, when shift is made to a second disk radial position located at a disk inner circumferential side from a first disk radial position to perform recording or reproduction, a rotation system for the optical disk at the second disk radial position is selected to be an angular velocity fixed system or a linear velocity fixed system on the basis of the positional relation of the first disk radial position and the both disk radial positions to a reference radial position, a recording or reproducing speed at the inner circumferential side is not lowered when a user data area is relatively small and is present only at the inner circumferential side, and a recording or reproducing speed at the outer circumferential side is not lowered when a user data area is relatively large and is present at both the inner and outer circumferential sides. In addition, regardless of the size of the user data area, at the time of access, a variation in the rotational speed of a disk motor at the second disk radial position is suppressed to secure the instant responsiveness. COPYRIGHT: (C)2006,JPO&NCIPI
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