Hitachi, Ltd.

Shigeyoshi Saito

Yuji Hata

Tsuyoshi Takahashi

Kazuo Ono

Takuji Ogawa

Masahiko Sega

Jyousei Shimizu

Yosuke Hamada

Haruaki Otsuki

A disk storage device comprises a microcomputer for estimating an external disturbance compensation signal and storing it and a first adder for adding the external disturbance compensation signal as a feedforward signal to a positioning compensation signal to a drive circuit. Where a positioning compensator for estimating a velocity signal based on a drive signal is provided, a difference signal between the drive signal and a signal proportional to the external disturbance compensation signal, instead of the drive signal, is applied to velocity estimation unit for correction.

Method and apparatus for eliminating external disturbances in a disk

A method of recording a servo signal on each track of a magnetic disk includes a first signal for demagnetizing the magnetic disk and a second signal for forming the servo signal. The recording width (core width) of the magnetic head is made greater than the width of the track. Parts for recording signals and not recording signals are set in each track. The first and second signals are selected and recorded in the signal recording part, thereby to form the servo signal. Current to be conducted to the magnetic head is cut in the part for not recording signals, and the track is skipped to the next part for recording signals. When the recording of the track has ended, the magnetic head is moved to the next track, and the above steps are repeated.

Servo information recording method for a storage apparatus

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Odawara, Japan

Shigeyoshi Saito