Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: In a disk drive, the fly-height of a recording head with respect to a recording medium is adjusted such that a target magnetic separation between the recording head and the recording medium is achieved. The target magnetic separation is determined based on the operating temperature of the disk drive. In addition, different target magnetic separations may be determined for different radial locations of the recording medium.

Abstract: 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.

Abstract: A disk drive includes a first flush cache memory location, a second flush cache memory location, and a controller for writing information associated with a flush cache write command alternatively between the first flush cache memory location and the second flush cache memory location.

Abstract: 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.

Abstract: 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.