Fujitsu Corporation

Fukitsu Limited

Kunihiro Shimada

Kazuhiko Takaishi

Atsushi Suzuki

Takeshi Hara

Yukio Abe

Mitsuo Kamimura

Yoshinari Higashino

Kiyoshi Sakuma

Kentaroh Katoh

Takashi Matsumoto

Eisaku Takahashi

Norio Yagi

Kenichi Myokan

Takehiko 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

A processing unit for effecting speed control in a drive control apparatus includes a storing unit having a first table which stores discrete values having exponential intervals, and a second table which stores multiples of normalized reference values having uniform intervals from each other and relating to a distance between a driven body subject to the speed control and a target position. The discrete values lie in a range over which the normalized reference values vary and are bound in a predetermined relation to a coefficient multiplied by the normalized reference values. The normalized reference values lie in the upper 1/2 range of said discrete values. A control target value generating unit calculates a control target value relating to a target speed of the driven body, by referring to the first and second tables.

Drive control apparatus for a disk drive

A storage device includes: a read/write mechanism which is actuated in accordance with a selected one of two or more sets of control data so that a read/write operation is carried out to read data from or write data onto a recording medium; a detection unit for detecting a source voltage from a host system, and for detecting whether one of source voltages from the host system has been switched to another source voltage; a control unit for controlling the read/write operation of the read/write mechanism in accordance with the detected source voltage; and a reset unit for resetting the control unit to an initial condition when the switching from the one of the source voltages to the another source voltage is detected as being in process, so that the controlling of the read/write mechanism is withheld until the end of the switching.

Storage device in which read/write operation is controlled in response

A magnetic disk drive for locking an actuator mounted with a magnetic head in a safety zone. The magnetic disk drive comprises a magnet, fixed yoke members and a stopper for setting a stop position of rotations of the rotary actuator in such a position that torque by the fixed yoke members and the magnet is maximized. The fixed yoke members form a magnetic circuit for the magnet in all or a part of a movable range of the rotary actuator. The fixed yoke members include a first area having a gap width uniformly reduced in a lock direction to retract the rotary actuator and a second area having a gap width smaller than a gap width of the first area. The fixed yoke members are mechanically separated from each other. The fixed yoke members further include a second area having a minimum gap width to lock the rotary actuator, a first area having such a gap that a gap width becomes smaller as it approaches the second area and a third area formed between the second area and the first area and having a gap width larger than a gap width of the second area.

Magnetic disk drive with automatic actuator and locking structure

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Kawasaki, Japan

Kunihiro Shimada