Disk device having a recording medium rotatable in a controlled stepwise manner in response to a reference clock signal of variable frequency

Abstract

A motor rotates a recording medium of a disk cartridge loaded in a disk device. A disk-type detecting unit detects whether the recording medium of the disk cartridge loaded in the disk device is a high-capacity recording medium or a low-capacity recording medium. A motor driving controlling unit causes the motor to rotate in accordance with a given reference clock signal, the motor driving controlling unit being set to a first mode for rotating the motor at a first rotation speed when the disk-type detecting unit detects that the recording medium of the loaded disk cartridge is the low-capacity recording medium and being set to a second mode for rotating the motor at a second rotation speed when the disk-type detecting unit detects that the recording medium of the loaded disk cartridge is the high-capacity recording medium, the second rotation speed being higher than the first rotation speed. A reference-clock-signal controlling unit, when the disk-type detecting unit detects that the recording medium of the loaded disk cartridge is the high-capacity recording medium, gradually increases a frequency of the reference clock signal to be provided to the motor driving controlling unit so that the rotation speed of the motor gradually increases, and, then, finally reaches the second rotation speed.