REVOLUTION CONTROL METHOD AND STORAGE DEVICE

摘要

PROBLEM TO BE SOLVED: To avoid the shortage of a read/write margin attendant on the high- speed revolution of a recording medium and also to maintain the states of a focusing servo and a tracking servo stable as to a revolution control method and a storage device. SOLUTION: In a storage device having a spindle motor for revolving an optical recording medium at two or more revolving speeds, this storage device is constituted so as to lower the revolving speeds when a read/write margin becomes equal to or lower than a first prescribed value or servo abnormality of the tracking servo or the focusing servo is generated by a frequency equal to or higher than a first prescribed frequency and to raise revolving speeds when the read/write margin becomes equal to or higher than a second prescribed value or the abnormality of the tracking servo or the focusing servo is generated by frequency equal to or lower than a second prescribed frequency.