Fujitsu Corporation

Kiyoshi Sakuma

Atsushi Suzuki

Takeshi Hara

Yukio Abe

Mitsuo Kamimura

Yoshinari Higashino

Kunihiro Shimada

Kentaroh Katoh

A magnetic disk apparatus includes a magnetic disk with normal and double servo sectors arranged alternately. If a servo interruption period corresponding to adjacent first servo sectors is a first servo interruption period, then a second servo interruption period that is a servo interruption period corresponding to adjacent first servo sector and second servo sector is equal to or less than half of the first servo interruption period.

Magnetic disk apparatus and method for monitoring high-frequency oscillation components

The controller circuit is designed to generate the positioning control signal based on the positional deviation of the head from a target recording track on a recording medium. A feedback control is effected to position the head right on a trajectory corresponding to the target recording track based on the generated positioning control signal. The positioning control signal is subjected to filtering at a notch filter. The cutoff frequency of the notch filter is set depending on the temperature detected at a thermal sensor. Even when the resonant frequency shifts in response to variation in temperature, the cutoff frequency of the notch filter follows the shift of the resonant frequency. A narrower bandwidth of the cutoff frequency still achieves reduction in the amplitude of the frequency component corresponding to the resonant frequency. The resonance or continuous vibration can reliably be prevented in the head. A rapid response can be accomplished in positioning the head right on a trajectory corresponding to the target recording track because of a narrower bandwidth of the cutoff frequency.

Controller circuit connectable to an actuator designed to position a head in a recording medium drive according to a filtered positioning control signal

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Kawasaki, Japan

Kiyoshi Sakuma