Hitachi, Ltd.

Hitachi Computer Peripherals Co., Ltd.

Tetsuji Kameoka

Toshiaki Tsuyoshi

Takashi Yamaguchi

Hajime Aoi

Hideaki Amano

Katsuhiro Tsuneta

Toshihisa Okazaki

Yoshihiro Moribe

Satoru Yamaura

Nobumasa Nishiyama

Kazuhisa Shiraishi

Kazuyoshi Hanada

Toshio Matsushita

Haruhiko Hosokawa

Akio Takatsuka

Sumio Obata

Masaya Tanaka

A magnetic disk apparatus includes a dual head equipped with an MR head for reading data and an inductive head for writing the data. One ID portion and one servo pattern are disposed in one sector and an unequal track pitch is formed. The ID portion is formed at the center of a radius of two positions to which the MR head is positioned at the time of reading the data and writing the data, respectively.

Magnetic disk apparatus

Increased memory capacity for a magnetic disk device is realized without degrading information error rate, by making the number of sectors at a given circumference of the disk variable in accordance with a radial direction of a disk. The number of sectors is made variable by deciding a predetermined information error rate from a ratio of reproduced signal output to noises of head, disk and amplifier at a maximum recording and reproducing frequency at a certain radial position along a disk.

Method and apparatus for optimizing the recording and reproducing of

A waveform equalizer for processing a signal read by a magnetic head from a magnetic written medium includes a slimming circuit which, in turn, has a first delay unit for delaying the read signal, a first attenuator connected in parallel with the first delay unit, a first differentiating circuit for receiving the output from the first delay unit and the output from the first attenuator, and a resistor connected to a first delay unit side input of the first differential circuit; and a pseudo-peak elimination circuit connected in series with the slimming circuit and including a circuit for separating the from the read signal the read signal or a signal reverse in phase to the read signal, a second delay unit for delaying the separated signal, a second attenuator for attenuating the amplitude of the separated signal, and a second differential circuit for receiving the read signal and the separated, delayed and attenuated signal.

Digital magnetic writing and reading apparatus

Growing community of inventors

Odawara, Japan

Tetsuji Kameoka