| 摘要 |
PROBLEM TO BE SOLVED: To achieve optimum rotation speed of a disk realizing low power consumption by specifying recording density of data lines in the direction of periphery of a disk, a disk rotation frequency, and a value of product of the number of servo information regions per round of a disk and the disk rotation frequency. SOLUTION: This device is constituted so that data line recording density in the direction of periphery of a disk is approximately 200 kbit/inch or more, a disk rotation frequency is approximately 60 Hz or less, and product of the number of servo information regions per round of a disk and the disk rotation frequency is 5000 or more. Further, assuming that an average rate required for recording data or reproducing data is Rate, a radius of most inner peripheral track is Rid a data line density is Ld, a track effective utilizing rate is (e), a track jump time is Tjmp, a retry tolerable time is Tretry, a disk rotation frequency is fr, and the number of servo regions in one round of a track is Ns, an equation is satisfied.
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