Patent application number | Description | Published |
20080239555 | Multi-quadrant wedge offset reduction field values for disk drive servo - A method for servo correction includes determining a first wedge offset reduction field value for a read element from information in a servo burst area of a wedge on a disk, storing the first wedge offset reduction field value, determining a second wedge offset reduction field value for the read element from information in the servo burst area of the wedge on the disk, storing the second wedge offset reduction field value, and estimating an offset value of the read element from a desired track on the disk using at least one of the first wedge offset reduction value or second wedge offset reduction field value. | 10-02-2008 |
20090040641 | METHOD AND APPARATUS FOR PHASE-SHIFT NULL-BURST-PATTERN - A media includes a plurality of tracks, a preamble portion including a set of signals, a first servo burst having a first plurality of signals written substantially in phase with the preamble portion, and a second servo burst written out of phase with the preamble and the first servo portion. The media may be housed within a disk drive that includes a transducing head to read information from the media, and a read channel to read information from the disk including the information associated with the first servo burst and the second servo burst. | 02-12-2009 |
20090086357 | IN DRIVE WRITTEN SPIRALS FOR SELF SERVO WRITING - A method of self servo writing is shown. In example embodiments, spirals or other indexing patterns can be written entirely within a hard disk drive, thus enabling self servo writing of the entire disk surface. Increased accuracy in spiral writing in turn increases the track density achievable using self servo writing techniques. One example method includes writing a first indexing pattern, then using the first indexing pattern to servo and write an adjacent second indexing pattern. Other example methods further include the use of back electromotive force (EMF) to increase accuracy in writing patterns such as spirals. | 04-02-2009 |
20090086366 | HARD DISK DRIVE OFF TRACK EVENT METHOD AND DEVICE - Methods and devices are shown that identify suitable second data operations after experiencing an off track event in a first data operation and perform the second data operations before correcting an off track event. Methods and device as shown provide increased efficiency in a hard disk drive. Time that normally would be wasted waiting for the read/write head to spin around for another try to correct an off track error is used to complete other nearby operations. | 04-02-2009 |
20090237842 | LOW TRACK-PER-INCH (TPI) ZONE WITH REDUCED NEED FOR ADJACENT-TRACK-ERASURE (ATE) REFRESH - Methods and systems are shown that specify at least one low track-per-inch (TPI) region and at least one normal TPI region on a disk. The low TPI region may be used to store information that may be rewritten frequently. The normal TPI region may be used to store information that may be rewritten less frequently. The low TPI region may reduce the need for adjacent-track-erasure (ATE) refresh. | 09-24-2009 |
20090244775 | ADJACENT-TRACK-ERASURE (ATE) REFRESH WITH INCREASED TRACK RESOLUTION FOR OFTEN-WRITTEN AREAS - Methods and systems are shown that specify using group counters and track counters to reduce the need for adjacent-track-erasure (ATE) refresh. A group threshold may be used to monitor the number of write operations to a group. The group threshold may be used to determine when it is necessary to monitor the write operations to the tracks in a group on an individual basis. | 10-01-2009 |
20100205367 | Method And System For Maintaining Cache Data Integrity With Flush-Cache Commands - A non-volatile memory location in a disk drive is utilized to store data residing in a write-cache upon receiving a flush-cache command from a host computer. If a subsequent flush-cache command is not issued within a predetermined time period, any data residing in the write-cache and stored in the non-volatile memory location that has not yet been written to its correct location on disk will be written to its correct location on disk. | 08-12-2010 |
20100246056 | DETERMINATION OF WEDGE OFFSET CORRECTION VALUES FOR A DISK DRIVE - In a disk drive, a wedge-based scheme is used to determine wedge offset correction values for a track of the disk drive. Correction values for the offset of each servo wedge are calculated wedge-by-wedge, based on the position error signal (PES) of the most recently measured servo wedge in combination with the measured PES of other servo wedges. To minimize transport delay of the servo, the majority of servo-control calculations may be pre-calculated prior to measuring the PES at the current wedge. Wedge offset correction values for a given servo wedge are corrected iteratively with each revolution of the storage disk. | 09-30-2010 |
20110013305 | PROXIMITY DETECTION METHOD FOR MAGNETIC HEAD AND RECORDING MEDIUM - Touchdown between a read/write head of disk drive and a recording medium is detected based on the variance in the frequency domain of position error signals (PES), each of which is measured after incrementally positioning the read/write head closer to the recording medium, from a baseline PES. The synchronous portion of the baseline PES is quantified and removed from the baseline PES and subsequent PES measurements to remove the effect of the synchronous portion of the baseline PES. The non-synchronous portion of the PES measured at a particular read/write head position may also be removed by synchronously averaging multiple PES measurements for each read/write head position. Detection of touchdown may be based on the rate of change of the variance in the frequency domain of PES relative to a baseline PES, instead of the absolute value of the variance. | 01-20-2011 |
20110075840 | METHOD AND SYSTEM FOR GENERATING RANDOM NUMBERS IN A STORAGE DEVICE - Random numbers are generated in a storage device based on the parity bits of successive position error signal (PES) samples. The parity bits of multiple PES samples are concatenated to form a random number having a desired number of bits. The random number may be further randomized by being processed with a deterministic random bit generator (DRBG) included in the firmware of the storage device. | 03-31-2011 |
20110141601 | PROXIMITY DETECTION METHOD FOR MAGNETIC HEAD AND RECORDING MEDIUM - Touchdown between a read/write head of disk drive and a recording medium is detected based on the variance in the frequency domain of position error signals (PES), each of which is measured after incrementally positioning the read/write head closer to the recording medium, from a baseline PES. The synchronous portion of the baseline PES is quantified and removed from the baseline PES and subsequent PES measurements to remove the effect of the synchronous portion of the baseline PES. The non-synchronous portion of the PES measured at a particular read/write head position may also be removed by synchronously averaging multiple PES measurements for each read/write head position. Detection of touchdown may be based on the rate of change of the variance in the frequency domain of PES relative to a baseline PES, instead of the absolute value of the variance. | 06-16-2011 |
20110242955 | PROXIMITY DETECTION METHOD FOR MAGNETIC HEAD AND RECORDING MEDIUM - Touchdown between a read/write head of disk drive and a recording medium is detected based on the variance in the frequency domain of position error signals (PES), each of which is measured after incrementally positioning the read/write head closer to the recording medium, from a baseline PES. The synchronous portion of the baseline PES is quantified and removed from the baseline PES and subsequent PES measurements to remove the effect of the synchronous portion of the baseline PES. The non-synchronous portion of the PES measured at a particular read/write head position may also be removed by synchronously averaging multiple PES measurements for each read/write head position. Detection of touchdown may be based on the rate of change of the variance in the frequency domain of PES relative to a baseline PES, instead of the absolute value of the variance. | 10-06-2011 |
20120275046 | SPLITTING A DATA STREAM BETWEEN TWO STORAGE MEDIA IN A HYBRID DISK DRIVE - A hybrid disk drive transfers a data stream to or from a host at an increased data transfer rate by time-multiplexing the data-carrying capacity of the system bus connecting the host and the disk drive. A portion of the data stream is stored on a non-volatile solid state memory device in the disk drive and a portion is written to a magnetic storage disk. The portion of the data stream written to the storage disk may be written on data tracks that are separated by empty data tracks corresponding to the data stored in the non-volatile solid state memory device. | 11-01-2012 |
20130242425 | WRITE REORDERING IN A HYBRID DISK DRIVE - A hybrid drive and associated methods increase the rate at which data are transferred to a nonvolatile storage medium in the hybrid drive. By using a large nonvolatile solid state memory device as cache memory for a magnetic disk drive, a very large number of write commands can be cached and subsequently reordered and executed in an efficient manner. In addition, strategic selection and reordering of only a portion of the write commands stored in the nonvolatile solid state memory device increases efficiency of the reordering process. | 09-19-2013 |
20140164675 | LOW-OVERHEAD STORAGE OF A HIBERNATION FILE IN A HYBRID DISK DRIVE - A hybrid drive and associated methods provide low-overhead storage of a hibernation file in the hybrid hard disk drive. During operation, the hybrid drive allocates a portion of solid-state memory in the drive that is large enough to accommodate a hibernation file associated with a host device of the hybrid drive. In addition to the erased memory blocks that are normally present during operation of the hybrid drive, the portion of solid-state memory allocated for accommodating the hibernation file may include over-provisioned memory blocks, blocks used to store a previous hibernation file that has been trimmed, and/or non-dirty blocks. | 06-12-2014 |
20140233132 | TEMPERATURE-DEFINED DATA-STORAGE POLICY FOR A HYBRID DISK DRIVE - Data is stored in a hybrid drive that includes a magnetic storage medium and a non-volatile solid-state device using a temperature-defined data-storage policy. According to the temperature-defined data storage policy, the drive can perform operations for modulating the temperature of the drive, minimizing increased wear on memory cells in the non-volatile solid-state device, and/or preventing data stored in the non-volatile solid-state device from being lost. | 08-21-2014 |
20140250272 | SYSTEM AND METHOD FOR FETCHING DATA DURING READS IN A DATA STORAGE DEVICE - A controller for a data storage device that includes a cache memory and a non-volatile solid state memory is configured to fetch data from the non-volatile solid state memory in response to a read command, conditionally fetch additional data from the non-volatile solid state memory in response to the read command, and then store some or all of the fetched data in the cache memory. The condition for additional data fetch is met when it is determined that a sequence of N (where N is two or more) most recent read commands is requesting data from a successively increasing and consecutive address range. The additional data fetch speeds up subsequent reads, especially when the requested data sizes are relatively small. When the requested data sizes are larger, improvements in read speeds can be achieved if the time between the large reads are well spaced. | 09-04-2014 |
20140258745 | POWER STATE CHANGE IN DISK DRIVE BASED ON DISK ACCESS HISTORY - A data storage device that includes a magnetic storage device selects one or more power states of the magnetic storage device based on a time interval since a most recent time data has been read from or written to the magnetic storage device. The power state of the magnetic storage device can be changed from a higher power consumption state to a lower power consumption state when the time interval exceeds a predetermined value. The power consumption state may be changed from an active servo state to an intermediate power consumption state, a park state, and/or a standby state, depending on the time elapsed since the most recent time data has been read from or written to the magnetic storage device. | 09-11-2014 |
20150055243 | TIMING OF POWER STATE CHANGE IN A DISK DRIVE BASED ON DISK ACCESS HISTORY - A data storage device that includes a magnetic storage device and a non-magnetic nonvolatile storage device that measures a hit rate of read/write commands that result in accesses to the non-magnetic nonvolatile storage device, and adjusts a length of a time period, such as an idle time, based on the hit rate. The duration of the time period can be set each time the magnetic storage device is accessed. Upon expiration of the time period, if the magnetic storage device has not yet been accessed, the magnetic storage device is changed from a higher power consumption state to a lower power consumption state. | 02-26-2015 |