Patent application number | Description | Published |
20100067342 | APPARATUS AND METHOD FOR ADJUSTING A FEED-FORWARD SIGNAL FOR SEEK CONTROL DURING A SEEK OPERATION - A hard disk drive control module has a feed-forward signal input port communicatively coupled with a reference model. The hard disk drive control module has a tracking error signal input port communicatively coupled with a magnetic transducer of the hard disk drive. The hard disk drive control module has an error calculator module configured for determining a difference between an estimated tracking error signal in response to a first feed-forward signal and an actual tracking error signal of the magnetic transducer in response to the first feed-forward signal. The hard disk drive control module has a feed-forward signal adjuster module configured for adjusting a gain and a phase for a second feed-forward signal based on the difference between the estimated tracking error signal in response to the first feed-forward signal and the actual tracking error signal of the magnetic transducer. The hard disk drive control module has a feed-forward signal adjustment output port communicatively coupled to the second feed-forward signal. | 03-18-2010 |
20100067357 | MAGNETIC RECORDING DISK DRIVE WITH ROTATIONAL VIBRATION COMPENSATION HAVING ADAPTIVE OPTIMIZATION OF VIBRATION SENSOR GAINS - A disk drive and a method for operating the disk drive compensates for rotational vibration (RV) by adaptively modifying the gains of two separate linear vibration sensors so the sensor gains are optimal under any given condition. The two sensors provide two signals S | 03-18-2010 |
20120002314 | THERMAL READ/WRITE OFFSET COMPENSATION - A HDD comprising a temperature sensor disposed inside the HDD configured to periodically measure temperature inside of said hard disk drive; a magnetic disk; a read head; a write head; memory for storing RWO data. The RWO data is a function of a distance between the read head and the write head. The HDD also includes a RWO data adjustor configured to adjust the RWO data in response to a change in temperature of the HDD to compensate for a change in the distance between the read head and the write head based on the change in temperature. | 01-05-2012 |
20120087037 | Patterned media with structured PES servo segments encoding local track position - Patterned magnetic media are described in which the servo sectors include at least two PES offset segments that can be used for the position error signal (PES) and identification of local track position. The two PES offset segments deviate from the track centerline in opposite directions. The lengths of the offset PES offset segments are systematically varied in a repeating pattern to provide a unique servo signal pattern for each track in a local group of adjacent tracks. The locally unique servo sector pattern allows the servo system to use the pattern of the signals generated from the offset and non-offset segments to determine the local track position, which is similar to information provided by the low order Gray code bits in prior art designs. Therefore, the number of bits in the track ID code can be reduced. | 04-12-2012 |
20130083420 | METHOD FOR CREATING BURST MAGNITUDE SERVO PATTERNS WITH UNIPOLAR BITS ON A MAGNETIC MEDIA OF A MAGNETIC DATA RECORDING SYSTEM - A magnetic data storage system having a magnetic disk having burst patterns for providing a position error signal (PES) wherein each magnetic burst pattern is offset from an adjacent burst pattern by ¼ track pitch. All of the magnetic bits of the burst patterns can be unipolar magnetized, and the bits of each burst pattern can be aligned with one another in radial and circumferential direction. The magnetic media can be a bit patterned media wherein the magnetic bits of the burst patterns are magnetically isolated portions separated by non-magnetic spaces or non-magnetic material. | 04-04-2013 |
20130135764 | IMPLEMENTING DATA TRACK PITCH ADJUSTMENT UNDER OPERATIONAL VIBRATION CONDITIONS - A method, apparatus and a data storage device are provided for implementing data track pitch adjustment for data written on a recordable surface of a storage device under operational vibration conditions. An operational vibration disturbance spectrum is detected during a write operation and the data track pitch is selectively adjusted based on the detected operational vibration disturbance spectrum. The adjusted track pitch information is saved and used during a read operation. | 05-30-2013 |
20140055883 | METHOD AND STRUCTURE FOR IMPROVING PERFORMANCE AND STORAGE DENSITY IN A DATA STORAGE DEVICE - A data storage device with improved data storage densities, coupled with lower hard error and write-inhibit events is described. A feed-forward write inhibit (FFWI) method enables data tracks to be written more densely. Alternatively, the FFWI method may reduce the hard error and write inhibit events to improve data storage performance. A concept of virtual tracks enables the FFWI method to be applied to the writing of circular data tracks with non-circular servo tracks, or to the writing of non-circular data tracks with PES data from circular servo tracks—in both cases, improvements to performance and/or storage densities are enabled. The FFWI method may also be applied to the case of both non-circular servo and data tracks. | 02-27-2014 |
20140168806 | Disk Drive Write-Inhibit Control Using Adaptive PES Predictor - Disk drives are described with a write inhibit control system with an adaptive head position predictor, e. g. an adaptive FIR filter, that includes a set of coefficients (weights) that are updated for each iteration based on the difference between past predictions and actual location measurement. Standard PES signals are used as the measure of the actual head position. The adaptive head position predictor uses a sequence of the most recent PES measurements and a corresponding set of coefficients (weight values) to calculate a predicted (future) PES value during each iteration. The write inhibit decision is then made by determining whether either a) the absolute value of the current measured PES is less than predetermined value L; or b) the absolute value of the estimated future PES is less than predetermined value L. | 06-19-2014 |
20140320995 | IMPLEMENTING DATA FREQUENCY AND DATA BITS PER SECTOR (BPS) CALIBRATION FOR NON-CIRCULAR DISK TRACKS - A method, apparatus and a data storage device are provided for implementing data frequency and data bits per sector (BPS) calibration for data written on a recordable surface including non-circular disk tracks of a storage device. A sector based BPS profile is created for data sectors on the recordable surface. The sector based BPS profile is used for modifying a number of data clock cycles based upon longer or shorter data sectors; and data clock frequency is dynamically adjusted based upon velocity jitter. | 10-30-2014 |
20150036235 | WRITE CURRENT AND FLY HEIGHT ADJUSTMENT FOR COMPENSATING MEDIA COERCIVITY VARIATION - A data storage device with compensation for coercivity variations in a magnetic disk storage medium is disclosed. Two procedures are executed to perform the coercivity compensation. In a first procedure, typically performed prior to writing of data, the coercivity at a number of locations on the disk is measured and stored. A second procedure writes data to locations on a magnetic disk storage medium having varying coercivities. To maintain writing widths within predefined limits, a writing parameter is varied according to a predetermined relationship between the value of the writing parameter and the coercivity. Choices of writing parameter comprise the writing current and fly height. The method may be employed for both data writing and self-servo writing of servo patterns. | 02-05-2015 |