Fujitsu Corporation

Yoshiyuki Kagami

Tatsuhiko Kosugi

Shuichi Hashimoto

Isamu Tomita

Takeyori Hara

Kazunori Mori

Ryuki Kubohara

Susumu Yoshida

Kouhei Takamatsu

Kohei Takamatsu

A servo-frame recording apparatus includes: a sector information rearranging section for rearranging serial bits of the sector information that is binary data; a first ExOR section for performing the ExOR (exclusive OR) on the sector information, the serial bits of which have been rearranged by said sector information rearranging section, and the track information, so that an exclusive logical sum is obtained; and a writing section for wiring the exclusive logical sum obtained by said ExOR section into the servo frame. With this configuration, a data length required for recording gray information and sector information can be shortened without lowering the reliability of a magnetic disk.

Method and apparatus for recording servo frame, storage disk, and method and apparatus for obtaining servo frame information

An eccentricity correction data recording method, a disk-shaped recording medium, a head position control method and an information recording and reproducing apparatus are disclosed for effective eccentricity correction on cylinders of a disk-shaped recording medium. The eccentricity correction data recording method is for position control over a recording and reproducing head on a disk-shaped recording medium having at least one user data recording area to record user data, the method including the step of recording the eccentricity correction data in a user data recording area.

Eccentricity correction data recording method and recording medium having eccentricity correction data

A recording apparatus capable of securely reading out data for causing a head to follow along circular tracks set virtually. Therefore, on-track control along the virtual tracks is possible by the conversion data on the discoid record medium even when, for example, the printed circuit board in a recording apparatus has been replaced.

Recording apparatus having discoid record mediums

A resonance-frequency measuring method is used for measuring a resonance frequency of an information recording/reproducing device reproducing information recorded on a medium by driving a mechanism unit. The resonance-frequency measuring method includes the measuring step of applying sine-wave oscillations at different frequencies one by one to the mechanism unit, and counting the number of times information reproduced upon application of each of the sine-wave oscillations differs from information indicating an aimed location, and the resonance-frequency determining step of determining the resonance frequency according to the number of times counted in the measuring step.

Resonance-frequency measuring method determining a resonance frequency by counting the number of off-track occurrences

A disk device performs position control of a head. An acquiring unit acquires correction information and check information from a disk for checking the correction information. A judging unit judges whether the correction information acquired should be used for correcting position information recorded in the disk, based on the correction information acquired and the check information acquired.

Disk device

There are provided a storage apparatus and a computer-readable recording medium, on whose storage areas, servo frames are arranged at uniform intervals in a spoke-like pattern. Each of the servo frames has an index bit storing section storing, as an index bit, part of an index pattern, which is operable to identify a storage area. The apparatus and the recording medium have a storage area recognizing unit for recognizing the storage areas based on the index bits, which are obtained by an index bit obtaining unit. The index bits, stored one in each of the index bit storing sections of the servo frames, are adapted to form, when being sequentially arranged, an index bit string in which such an index pattern repeatedly appears.

Storage apparatus and storage medium

There is provided a head control method controlling move of a head on a discoidal recording medium including the steps of: partitioning the discoidal recording medium which has position information recorded thereon at radially equal spacing into a plurality of zones; and demodulating the position information using a coefficient set for each of the zones.

Head control method and recording apparatus

A resonance-frequency measuring method is used for measuring a resonance frequency of an information recording/reproducing device reproducing information recorded on a medium by driving a mechanism unit. The resonance-frequency measuring method comprises the measuring step of applying sine-wave oscillations at different frequencies one by one to the mechanism unit, and counting the number of times information reproduced upon application of each of the sine-wave oscillations differs from information indicating an aimed location, and the resonance-frequency determining step of determining the resonance frequency according to the number of times counted in the measuring step.

A servo control method and an information storage device are provided. In the method and device, positional information is detected in accordance with servo information including a plurality of positional regions having phase differences between tracks. The positional regions consist of a first positional region in which the phase difference between tracks is &plus;90&deg;, a second positional region in which the phase difference between tracks is &minus;90&deg;, a third positional region in which the phase difference between tracks is &plus;90&deg;, and a fourth positional region in which the phase difference between tracks is &minus;135&deg;. A deviation from a reference track is detected from the phase difference between the vector of a reproduction signal of the second positional region and the vector of a reproduction signal of the fourth positional region. Thus, a wide range of deviation can be detected.

Growing community of inventors

Kawasaki, Japan

Yoshiyuki Kagami