International Business Machines Corporation

Hitachi Global Storage Technologies Netherlands B.v.

Lenovo (Singapore) Pte. Ltd.

Hitachi Global Technologies

Yuzo Nakagawa

Naoyuki Kagami

Sri Muthuthamby Sri-Jayantha

Hien Phu Dang

Tetsuo Ueda

Isao Yoneda

Fuminori Sai

Arun Sharma

Kiyoshi Satoh

Akira Tokizono

Yukio Fukushima

Nobuya Matsubara

Thomas R Albrecht

Terumi Takashi

Vijayeshwar Das Khanna

Gerard McVicker

Timothy C Reiley

Koichi Arai

Kenji Kuroki

Masayuki Murakami

Yoshiju Watanabe

Hiroki Kitahori

Tetsuya Tamura

Kenji Ogasawara

Hiroshi Uchiike

Keishi Takahashi

Takashi Nakamura

Tatsuya Sakai

Takashi Kuroda

Toshio Kakihara

Katsuhiko Katoh

Yuji Kigami

Nobuhisa Koide

Tsutomu Numata

Hjalmar H Ottesen

Yoshimi Masuda

Masashi Murai

Masayuki Takeuchi

Erno H Klassen

Shyunji Ono

Masakazu Kubo

Shunsuke Kobayashi

Emi Shimono

A method for writing data to a disk drive. The method includes: receiving a write command; and, determining whether a beginning and an end of a rewrite area specified by the write command agree with boundaries of large-sized data sectors on a disk. The method also includes: reading head and tail data sectors and making a backup of the head and tail data sectors in first and second non-volatile memory areas, respectively, if the beginning of the rewrite area does not agree with the boundaries. The method includes starting a rewrite of the rewrite area after completing backups into first and second non-volatile memory areas. Moreover, the method includes: determining a state stage by using data in first, second, third and fourth non-volatile memory areas if a power shut-down occurs during execution of the write command; and, executing a recovery process in accordance with the determined state stage.

Disk drive including a host interface supporting different sizes of data sectors and method for writing data thereto

A method (and structure) senses a rotational vibration of a disk drive. The disk drive includes a rotating disk. The disk includes a plurality of reference bits across a surface thereof. The method (and structure) includes detecting the reference bits across a pattern on the rotating disk, and analyzing a time interval between adjacent ones of the reference bits.

Method and system for time-shift based rotational vibration sensing in disk drives

To improve the probability of error correction, thereby generating correct read data. Data is read from the same sector by a number of times and a majority decision is done in the same address, thereby the most frequently read value is regarded as the true data value in the address. For example, for an address 00, '00' is handled as a true data value.

Data storage apparatus, read data processor, and read data processing method

The hard disk drive comprises: a magnetic diskhaving servo information stored; magnetic headsseeking on the magnetic diskand staying at a predetermined position to read or write data; a voice coil motormoving the magnetic headsto the predetermined position of the magnetic diska position controller supplying a driving current to the voice coil motorbased on the servo information read by the magnetic headsThe position controller includes: a CPUoutputting a speed control value based on the servo information; a DACand a VCM driverconverting the speed control value into the driving current; and a controllerlimiting a driving speed of the voice coil motorin a case that an output timing of the speed control value is shifted.

Head movement controlling based on servo generated speed control values

A disk drive, a servo controller, and a controller which have realized high-degree control by lightening processing load to a microprocessor unit (MPU) without increasing cost is disclosed. An analog/digital (AD) converter (ADC) performs the AD conversions of the regenerated levels A, B, C, and D of burst patterns supplied from a channel and retains the converted levels in an ADC register. A servo assist (SA) computes parameters, such as the position error of a head, independently of an MPU, based on the regenerated levels of the burst patterns retained in the ADC register and an instruction from the MPU retained in a SRAM. Based on the computed parameters, the SA computes servo data (DACOUT) for driving a voice coil motor and supplies the servo data to the DAC section of a VCM driver section through a SIO.

Disk drive, servo control unit, and control unit

A method and apparatus to provide a retract circuit that can correspond to the tendency toward miniaturization and low supply voltage. When drive supply voltage Vcc is applied, a retract circuit charges a retract condenser Cr with boosted voltage Vup, equal to three times Vcc, generated by a booster circuit. Then, if the drive supply voltage Vcc is cut off and a VCM driver stops, the retract circuit detects power-off with a power OFF sense circuit, and provides retract delay time by a retract delay circuit. Furthermore, when the retract delay time elapses after the drive power supply is turned off, the retract driver switches the switching circuits on, discharges the retract condenser, charged at the boosted voltage, supplies discharge current to a voice coil, and retracts the head assembly.

Disk drive with improved retract circuit and method

Methods and systems for detecting and correcting for undesirable vibrations impacting the servo systems in data storage devices. A detection technique is provided wherein a detection filter is configured to scan a position signal of the servo system across a range of frequencies, and, at each respective scanned frequency, record an amplitude associated therewith. The recorded amplitudes are examined to determine whether any exceed a threshold, thereby locating a peak frequency of the vibration. Using the detected peak frequency of the vibration, a corrective filter is configured to operate about the peak frequency of vibration, thereby reducing its impact on the position signal in the servo system. Optimum detection and correction filter structures are disclosed, as are techniques for addressing filter state vectors as initial conditions as the corrective filters are repeatedly engaged during successive settle-out and track follow cycles (between seeks), as are continuous adaptation techniques for changing vibration environments.

Adaptive vibration control for servo systems in data storage devices

A hard disk drive (HDD) having a control unit that reduces the number of control signals required to control the operation of the channel and amplifier. The HDD includes a control unit for controlling reading or writing data from or to a magnetic head, a preamplifier for amplifying the data from the magnetic head, and a channel module which is controlled by the control unit. The channel module converts digital data signals to data write signals and also converts analog signals from the preamplifier to digital signals. Control information is transmitted to the channel module over the data bus which is used to transmit or receive data read/write signals. The channel module performs control in response to transmitted control information.

Method and apparatus for controlling read and write operations in a storage device

An arrangement structure of the printed circuit board and the interface cable connector of a magnetic disk drive for increasing the degree of freedom of the arrangement of a spindle motor, and for minimizing the size of a printed circuit board. An interface cable connector is disposed on the side opposite to the spindle motor, and the printed circuit board is sized so as not to contact with the spindle motor in the height direction. This allows the degree of freedom of the arrangement of the spindle motor to increase. Further, the distance between the interface cable connector and the preamplifier connector on the printed circuit board is short. Thus, the size of the printed circuit board can be made as small as possible.

Arrangement structure of the printed circuit board and the interface cable connector of a magnetic disk drive

A disk drive system, includes an arm for mounting a head, and at least one component, coupled to the arm, for being synchronized to maintain a zero net angular momentum of the arm and the at least one component. Another disk drive system including a read/write head, includes a torque counter-generating member for being synchronized to maintain a zero net angular momentum of the head.

Disk drive rotary actuator system including synchronous counter torque

A magnetic head position detecting method is provided in which a first and a second position detection signal representative of a particular position of a magnetic head with respect to a magnetic disk is obtained. The first and the second position detection signal preferably is obtained by utilizing a burst pattern formed on the magnetic disk. Subsequently, a third position detection signal is generated by multiplying the first and the second position detection signals by a predetermined gain so that the third position detection signal changes linearly. The particular position of the magnetic head is detected by using the third position detection signal. In addition, a magnetic disk apparatus implementing the magnetic head position detecting method is provided.

Magnetic head position detecting method and magnetic disk apparatus

A disk and a disk drive having a servo start mark for identifying a servo-information start position recorded on the disk is provided. The servo start mark has a plurality of bit patterns unused for other areas in servo information. A method for identifying the position of a signal transducer on a disk is also provided in which it is judged that the signal transducer is present at a predetermined position even if an error is present and the error is a one-bit error. This is accomplished by assuming that the position is correct when the following conditions are confirmed: (a) a parity error occurs in a read servo-information bit pattern and (b) read servo-information bit pattern does not coincide with servo information of an adjacent track.

Method and apparatus for indicating start of servo information on a

Disclosed is a disk drive which includes a disk, a spindle motor for rotating the disk, an actuator for moving a transducer over the disk, a pivotably mounted latch for locking the actuator, and a controller for rotating the spindle motor at at least two rates. The latch has two ends. On one end, the latch includes a locking member for engaging a notch in the actuator. On the other end of the latch is a vane for producing a force on the latch caused by the airflow from the rotating disk in the disk drive.

Actuator locking system of disk unit

In a servo controlled device such as a disk drive actuator or a robot that is driven by a DC motor and must seek from one position to another position and settle at the target position in a minimum time, a deadbeat control response can effect settling in a minimum number of servo sample times with no steady state error and no ripple between sampling instants. The device design, initial conditions entering the deadbeat controlled mode and the frequency of servo samples can be used to enable deadbeat control by limiting the control current to a value that will not saturate the motor coil or exceed the linear operating range of the controlled device.

deadbeat control of disk drive actuator

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Hiratsuka, Japan

Yuzo Nakagawa