Fujitsu Corporation

Fukitsu Limited

Eisaku Takahashi

Kazuhiko Ikeuchi

Hideo Takahashi

Hidejirou Daikokuya

Mikio Ito

Norihide Kubota

Yoshihito Konta

Mitsuo Kamimura

Eiji Okamura

Kazuhide Ohba

Masao Tsunekawa

Atsushi Satoh

Chihiro Ono

Isao Suda

Tatsuya Gofuku

Takashi Tokairin

Hiroaki Sato

Kazuhiko Takaishi

Tsutomu Sasaki

Naoyoshi Toshine

Yasutake Sato

Yukihiro Yoshiya

Yusuke Inai

Hirofumi Suzuki

Taturo Sasamoto

Kunihiro Shimada

Masaru Shimmitsu

Nobuyuki Kikuchi

Norihiko Suzuki

Tadashi Hirano

Takahiro Ono

Tsuyoshi Nakagami

Koichi Tohkairin

Kenji Endo

Hirokazu Ishizaki

Chiharu Ohba

Masaru Saiki

Teiji Yoshida

Masami Ikeno

Yuuji Noda

A storage control device for controlling the storage device including a medium for storing data, logical address information, and address translation information and a memory for storing the address translation information read from the medium includes a first receiver for receiving a write request including logical address information, a first sending module for sending a read request including the logical address information of the write request to the storage device, a second receiver for receiving data and logical address information stored in the medium in accordance with the read request from the storage device, and a second sending module for sending an instruction to cause the storage device to write the address translation information stored in the medium into the memory when the logical address information received by the second receiver is different from logical address information included in the write request.

Storage control device and storage system

In a RAID apparatus, an error determining processing unit determines whether an HDD is normal based on an error determining condition obtained from an amount of increase of NON MEDIUM ERROR COUNT and the number of accesses memorized on a control table, and detects the HDD with abnormal performance.

Abnormality determining apparatus

A method of controlling a RAID system including a plurality of disk devices is provided. The method allows for reading data recorded onto an area adjacent to an area where a write error occurs when the write error is detected while data is written into the disk device. When an error is detected from the data read from the adjacent area, the data recorded onto the adjacent area is restored by using a RAID function and the restored data is written into the adjacent area.

Method and data storage devices for a RAID system

In a storage system, a disk device performs recovery and transfers read data to a control device, and the control device judges the validity of the recovery to prevent a transfer of erroneous data. A control device read-accesses a disk device, and the disk device returns read data and a recovered read error response. A control device, at the time of an initial recovered read error, performs a retry of a similar command, and if an error does not occur for read commands including the retry read command, judges the data to be valid. Uncertain data (suspect data) upon occurrence of a recovered read error is restored through disk retry, and accurate read data can be transferred to the host.

Storage system, storage control device, and storage control method detecting read error response and performing retry read access to determine whether response includes an error or is valid

A recording-medium controlling apparatus that performs a read-access and a write-access of a recording medium in response to access request from a higher-level apparatus, detects a read error that occurs at a time of the read access, and performs a replacement processing, includes an error detecting unit that tries a plurality of the read accesses to an error location on the recording medium to detect whether the read error recurs a plurality of times; and a replacement processing unit that performs, when the error detecting unit detects that the read error recurs a plurality of times, a replacement processing for the error location.

Method and apparatus for replacement processing

High-accuracy position signals are obtained by correcting nonlinear position sensitivities of two phase signals demodulated from two-phase servo information, into linear ones. A position sensitivity adjusting unit detects the signal level at the intersection of position signals N and Q having different phases by a predetermined track pitch which are demodulated from read signals of two-phase servo information buried and recorded in a disk medium and makes an adjustment of the gain of an AGC amplifier so that the intersection signal level coincides with a predetermined level. A sensitivity correcting unit corrects into linear position sensitivities the nonlinear position sensitivities approximated by sine functions or cosine functions relative to the actual track position X of the two position signals N and Q output from the AGC amplifier.

Storage apparatus and position sensitivity setting method

A disk apparatus has a disk medium with sector areas that have a servo area and a data area along the same cylinder. The servo areas also have a sector mark indicative of the servo area, a code indicative of a cylinder address, and a predetermined servo pattern to detect a head position, all magnetically recorded in the servo area. A disk control section uses a head portion to detect the head position on the basis of a read signal of the servo pattern and positions the head portion at an arbitrary cylinder to perform reading and writing operations. The disk apparatus also has a time measuring counter for starting to measure an elapsed time each time a predetermined position in the servo area is detected, and a time setting register for storing a time from a detection time point of the predetermined position in the servo area to the generation of the sector pulse. A coincidence detecting section is provided to detect that the elapsed time measured by the time measuring counter coincides with the set time of the register, while a pulse generating section is provided for generating the sector pulse when the coincidence is detected by the coincidence detecting section.

Disk apparatus using coincidence detection to generate variable sector

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

Two position signals N and Q having phases different by 90.degree. are demodulated from discrete readout signals of two-phase servo information through a position signal demodulating circuit. A level detecting circuit compares sizes of two position signals (absolute values) N and Q discretely available from the position signal demodulating circuit through seek operation at a certain speed. A cross-point C is calculated on the basis of two smaller discrete values Z and Y immediately prior to reversal of the size relationship of the two signals at the cross-point and a smaller discrete value X immediately after passage through the cross-point, and the thus calculated cross-point value C is set in an AGC amplifier as a reference amplitude value. The AGC amplifier adjusts the positional sensitivity to a certain value by amplifying the cross-point level of the two position signals N and Q so as to agree with the set reference amplitude value.

Apparatus and method for adjusting positional sensitivity of disk unit

For a balance adjustment due to a reduction in size and weight of an actuator, an arm portion, an axis attaching portion, and a coil supporting portion are arranged so that the centers of gravity on the coil side are located on a straight line connecting a rotational center and the center of gravity on the head side. Further, the improvement of an assembling efficiency of a VCM, an increase in torque, a one-touch fixing of an FPC connecting band, a noise prevention of a read pattern, and an insulation between the base and cover due to a bias of an MR read head are accomplished. A sector mark is detected by comparing a peak detection pulse and its reference polarity signal. A redundancy is provided to a reference detection polarity signal so that a read signal can be detected even if any one of the read signals of the sector marks is dropped out. A gray code detecting section for recognizing a cylinder address also detects on the basis of a peak detection pulse and a polarity signal due to the reading of a gray code. A memory space to store a program is divided into an ROM space of a small electric power consumption and an RAM space of a large electric power consumption and stores each peculiar program.

Head positioning control for disk apparatus using peak detection,

Two-phase servo patterns are recorded on a servo area of a data medium of a data storage apparatus such that patterns Q+, N+, N- and Q- are recorded in the stated order, there being a phase shift of 90 degrees between position information N and position information Q.

Data storage apparatus having servo control system

A disk apparatus wherein a disk is rotated by a rotating motor, and a source power supplied to the rotating motor is monitored, which includes: a memory unit for storing an initial source voltage value before a process of a rotating motor acceleration is started; a detecting unit for periodically detecting a source voltage value related to the source power; a comparing unit for comparing the source voltage value, detected by the detecting unit during the process of the rotating motor acceleration, with the initial source voltage value stored in the memory unit, and for outputting a voltage fluctuation indicated by a difference between the source voltage value and the initial source voltage value; and a control unit for setting a quantity of the source power supplied to the rotating motor, to a smaller quantity in response to the voltage fluctuation output by the comparing unit.

Apparatus having source power control unit responsive to voltage

A spindle sync control system for a plurality of magnetic disk drives connected in parallel to a host computer. The system is capable of reducing lost time and preventing a system from going down. The system includes a discriminator (25A) for discriminating the presence or absence of a reference index, a medium index and a Hall index; an offset calculator (25B) for calculating an offset value between the medium, index and Hall index before starting spindle sync control; a memory means (26) for storing the thus calculated offset value; a phase difference calculator means (25C) for calculating a phase difference between the reference index and the medium index; and a determination means (25D) for determining a driving control value for rotating a spindle motor (7) according to the thus calculated phase difference.

Spindle synchronization controller using advance calculation and offset

A mechanical variation of a voice coil motor and an electrical variation of a servo loop are corrected, thereby performing a head positioning control of a high accuracy. When a measurement mode is set, a zero-cross frequency f.sub.0 at which a gain of open loop characteristics of the servo loop is set to 0 dB (gain =1) is known. By adding the frequency f.sub.0 to the servo loop, an open loop gain G.sub.OP is obtained. A correction coefficient K to set the open loop gain into an ideal value 0 dB (gain=1) is obtained as K=1/G.sub.OP and is stored into a correction table. In the ordinary access, a drive signal of an actuator is corrected by a correction coefficient K read out with reference to the correction table in accordance with the present cylinder position and the corrected drive signal is sent to the actuator.

Positioning control method and apparatus of head which is used in

A data head offset detecting circuit in a magnetic disk unit includes a first offset detector that detects an offset .beta. based on servo information on a data surface read by the data head, a second offset detector that detects an offset .gamma. based on servo information on the servo surface read by the servo head, and an offset calculator for calculating a real offset .alpha. resulting from the subtracting of the offset .gamma. from the offset .beta.. By using the above circuit, an offset for a correction of an offtrack is detected accurately even when the heads are vibrating.

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Higashine, Japan

Eisaku Takahashi