Patent application number | Description | Published |
20100134916 | MAGNETIC RECORDING MEDIUM AND MAGNETIC STORAGE DEVICE - According to one embodiment, a magnetic recording medium includes a disc substrate, a first recording layer, and a second recording layer. The first recording layer is disposed in at least one of a plurality of data storage areas partitioned in a radial direction on the disc substrate. A magnetic material is deposited on the first recording layer. The second recording layer is disposed in the data storage areas except the data storage area where the first recording layer is disposed. The second recording layer includes a magnetic material and a non-magnetic material that are alternately arranged in the in-plane direction of the upper surface of the disc substrate. | 06-03-2010 |
20120081810 | MAGNETIC DISK DRIVE USING OFFSET IN POSITIONING HEAD TO READ DATA AND HEAD POSITIONING METHOD - According to one embodiment, a magnetic disk drive comprises a write count memory, a read offset setting module and a controller. The write count memory stores a write count for each track or for each zone on a disk. The read offset setting module sets, in accordance with a write count for an adjacent track to a target track or for a zone to which the adjacent track belongs, an offset from a predetermined position on the target track in a read position in which a head is to be positioned when the head is positioned on the target track for data read. The write count is stored in the write count memory. The controller positions the head in a position shifted from the predetermined position by the set offset. | 04-05-2012 |
20120307400 | DISK STORAGE APPARATUS, DISK CONTROL APPARATUS AND WRITE CONTROL METHOD - According to one embodiment, a disk storage apparatus includes a write module and a controller. The write module is configured to move a write head over a disk, and to perform the shingled write method, recording data in the first track while erasing data from a part of the second, i.e., adjacent track. The controller is configured to acquire a first head positioning error with respect to the first track and a second head positioning error with respect to the second track. If the first head positioning error exceeds an off-track threshold value, indicating that the data may no longer be maintained in the first and second tracks, the controller inhibits the data writing. | 12-06-2012 |
20130182348 | MAGNETIC DISK DRIVE AND DATA BUFFERING METHOD APPLIED TO THE SAME - According to one embodiment, there is provided a method of temporarily storing data in a buffer. The method determines whether data written based on sequential writing is of a first type or a second type in data type. The method stores the written data in association with the determined data type in the buffer. The method further controls the buffer so that the data of the first type stored in the buffer may be held in the buffer for a length of time twice as long as time T | 07-18-2013 |
20130182350 | MAGNETIC DISK DRIVE AND METHOD FOR SERVO BURST DATA CORRECTION - According to one embodiment, a magnetic disk includes a plurality of tracks each having a plurality of servo frames with servo burst data and repeatable runout correction data written thereto. The repeatable runout correction data includes a pattern repeated at a predetermined period and is written so that beginning of write is delayed by a time corresponding to a correction amount with respect to a base point corresponding to a synchronization timing position in the servo frame. A detector detects a phase delay amount corresponding to a time elapsed until the repeated pattern is read from the servo frame by a magnetic head, with respect to the synchronization timing position. | 07-18-2013 |
20140029126 | DISK STORAGE APPARATUS AND DATA PROTECTION METHOD - A disk storage apparatus according to one embodiment includes a head, a storage device, a write module and a controller. The head writes data on a disk. The storage device has a storage area for temporarily storing the data written by the head. The write module writes data to tracks on a disk, while partially overlapping the data with previously written data to adjacent track. The controller detects a drift-off write of the head while writing data, determines a drift-off write area in which the drift-off write is occurred, and protects the data written in the storage area, if the data is written in the drift-off write area. | 01-30-2014 |
20140118857 | INFORMATION WRITE APPARATUS AND INFORMATION WRITE METHOD - According to one embodiment, an information write apparatus writes a track on a magnetic disk by a shingled write recording method. The information write apparatus calculates a write target position of the track based on a pitch. The information write apparatus calculates a positioning error. The information write apparatus stores the calculated positioning error. The information write apparatus integrates positioning errors of tracks written before the predetermined track is written, and corrects a write target position based on the integrated positioning error. The information write apparatus controls the position of the write head based on the corrected write target position. | 05-01-2014 |
20140153127 | DISK STORAGE APPARATUS AND METHOD FOR SERVO CONTROLLING - According to one embodiment, a disk storage apparatus includes an interrupt controller and a servo controller. The interrupt controller determines whether or not to carry out servo interrupt processing and holds a number of negative results of the determination. The servo controller includes an internal model configured to calculate an estimated current position of the head. The servo controller corrects a state of the internal model based on the number of negative results of the determination and performs head positioning control based on a result of a calculation of the internal model, if the result of the determination by the interrupt controller is affirmative. | 06-05-2014 |
20140153131 | DISK STORAGE APPARATUS AND METHOD FOR SERVO CONTROLLING - According to one embodiment, a disk storage apparatus includes a servo system. The servo system includes a state observer and performs a seek operation up to a target position with a current position of a head undetermined. The servo system performs the seek operation based on initial values including a temporary position, while allowing the state observer to operate based on the initial values, until the current position is determined. The servo system determines the current position based on the servo data read from the plurality of servo areas by the read module and a result of estimation by the state observer. | 06-05-2014 |
20150043099 | METHOD FOR GENERATING ADDRESS DATA AND DISK STORAGE APPARATUS - According to one embodiment, there is provided a method for generating address data. The method generates a first code corresponding to a cylinder number. The cylinder number is divided and recorded on servo sectors in association with an identification of a cylinder on a disk. The first code is formed of some codes obtained by dividing the cylinder number based on a number of each of the servo sectors. The method generates a second code corresponding to address data for each of the servo sectors, by encoding the first code based on the servo sector number and a servo format number. The servo format number is used to identify a format of each of the servo sectors. | 02-12-2015 |
Patent application number | Description | Published |
20080312891 | DESIGN METHOD, DESIGN SUPPORT APPARATUS, AND COMPUTER PRODUCT FOR FEEDBACK CONTROL SYSTEM - A control system is designed in which a controlled plant is controlled based on output feedback from the controlled plant. An all-pass filter is modeled that is formed of a synthesis of a notch filter compensating for a resonance mode in the control system and the resonance mode. A design controlled plant including the all-pass filter is determined. A controller controls the design controlled plant and includes a weighting function, and, after the weighting function is derived, gain of the weighting function is adjusted using desired gain crossover frequency and phase margin. A phase variable included in a phase-lead weight is determined, and thus the weighting function is determined. H∞ loop shaping is applied to the weighting function and the design controlled plant to obtain an H∞ loop controller. | 12-18-2008 |
20090190251 | DATA RECORDING METHOD - A recording method for a disk device includes the following steps. Sequential data is written into the medium along the track in a predetermined radial direction. Information indicating an end position along the track where the end of the sequential data is written into is stored. The information is read when additional sequential data is to be written into the medium. The additional data is written from a position along the track next to the end position indicated by the information in the predetermined radial direction. The information is updated so as to indicate an end position along the track where the end of the additional sequential data is written into. | 07-30-2009 |
20090207523 | MAGNETIC RECORDING MEDIUM AND MAGNETIC RECORDING APPARATUS - A magnetic recording medium formed on a substrate. The magnetic recording medium includes a data region including a plurality of magnetic dots arranged at predetermined positions on the substrate, for recording information; and a servo region for specifying the positions of the magnetic dots, the servo region including a plurality of magnetic segments arranged at predetermined positions on the substrate, each of the magnetic segments being smaller than each of the magnetic dots. | 08-20-2009 |
20090231749 | INFORMATION STORAGE DEVICE - A drive section which moves a head above an information storage medium and a control section are provided, and each track on the information storage medium is made up of alternating first regions for writing in and reading out user information and second regions that store information for the positioning of the head. The control section is provided with a feedback control value determining section for eliminating the difference between the head position and the representative position of the first region, which is an access object, a performing control value determining section for determining the performing control value for the performing control by finding the logical control value associated with the first region where the feedback control value is determined and adding the feedback control value to this logical control value and a performing control section for actually controlling the drive section. | 09-17-2009 |
20090284858 | MAGNETIC RECORDING APPARATUS AND CLOCK SIGNAL GENERATING METHOD - According to an aspect of the embodiment, in a magnetic recording apparatus having a magnetic recording medium of a patterned media system, a voltage generated between both terminals of a magnetic field generating coil in a case that a DC current is supplied to a recording element of a magnetic head is measured by a voltage measuring circuit in order to perform accurate recording at the center of each of magnetic body regions sectioned with non-magnetic body regions. Based on the measured voltage, a change in coil inductance in passage of the magnetic head over a magnetic body region and a non-magnetic body region in a patterned media is detected by a voltage change detecting circuit. A write clock signal which synchronizes with the change in coil inductance is generated by a clock signal generating circuit. | 11-19-2009 |
20100033867 | MAGNETIC STORAGE MEDIUM AND MAGNETIC RECORDING DEVICE - A patterned media type magnetic storage medium has separated magnetic dots formed a data area having a first magnetic dots and a servo area. The micro position detection portion in the servo area is constructed with first and second dot arrays having a different number of second magnetic dots in the circumference direction and face with the center line that the first magnetic dots of the data area in the magnetic storage medium are disposed, as the axis. The area of the magnetic dot constituting the micro position detection portion of the servo area is small, so the coercive force of the servo area increases. The frequency is changed depending on the number of magnetic dots, and the phase is changed depending on the position of the magnetic dot array in the radius direction with the center line as an axis. | 02-11-2010 |