Abstract: Apparatus for two dimensional data reading. In accordance with some embodiments, a magnetic read element has a plurality of read sensors positioned symmetrically about a pivot point with at least two of the read sensors configured to concurrently read two dimensional user data while being immune to skew angle misalignment.

Abstract: An assembly and method to determine adjacent track coherence is disclosed. The assembly includes coherence circuitry configured to receive phase and frequency offsets from timing recovery circuitry and determine an inter-track phase and frequency coherence between the encoded data on a first track and the encoded data on a second track adjacent to the first track utilizing the frequency and phase offsets from the timing recovery circuitry for the output signals corresponding to the first and second tracks.

Abstract: Apparatus and method for light source power control during the writing of data to a storage medium. In accordance with various embodiments, a data recording head is provided having a magnetic transducer and a light source. The light source is driven at a first power level to irradiate an adjacent storage medium prior to the writing if data to the medium using the magnetic transducer. The first power level is insufficient to alter a magnetization state of the medium. The light source is subsequently transitioned to a higher, second power level to irradiate the storage medium during the writing of data to said medium using the magnetic transducer, the second power level being sufficient to alter said magnetization state of the medium.

Abstract: A communication system includes a physical communication channel. A signal is transmitted across the communication channel from a transmit end of the channel to a receive end of the channel. A plurality of processing branches process the signal at the receive end of the communication channel. This reduces complexity of the receive channel, without reducing a bandwidth of the given communication channel, and without comprising performance.

Abstract: A communication system includes a physical communication channel. A signal is transmitted across the communication channel from a transmit end of the channel to a receive end of the channel. A plurality of processing branches process the signal at the receive end of the communication channel. This reduces complexity of the receive channel, without reducing a bandwidth of the given communication channel, and without comprising performance.

Abstract: An equalizer employed in conjunction with bit-patterned media (BPM) is designed to take advantage of a common topology associated with BPM in which each data track is comprised of a plurality of sub-tracks. The equalizer-target filter pair is designed as multiple-input/multiple-output (MIMO) system, in which the readback signal is divided into readback signals associated with each sub-track. The MIMO equalizer takes into account differences in the channel response associated with each sub-track. A detector is configured to receive a plurality of equalized inputs provided by the MIMO equalizer, wherein the detector generates in response estimates of the user data stored on each of the plurality of sub-tracks.

Abstract: An apparatus comprises a storage medium, a recording head, a source of electromagnetic radiation, and a control circuit for modulating the source of electromagnetic radiation in response to a static deviation of a spacing between the recording head and the storage medium. A method of compensating a static deviation of a spacing between a recording head and a storage medium performed by the apparatus, and a method of precompensating for nonlinear transition shifts in a heat assisted magnetic recording system, are also provided.

Abstract: A magnetic storage medium comprises a plurality of discrete magnetic elements and first and second adjoining servo sectors. Each of the servo sectors comprises first and second rows of the discrete magnetic elements extending in a track direction. The second row of the discrete magnetic elements are stacked relative to the discrete magnetic elements of the first row in a cross-track direction that is perpendicular to the track direction. The discrete magnetic elements of the first servo sector are staggered in the cross-track direction relative to the discrete magnetic elements of the second servo sector.

Abstract: A timing detector adapted for timing recovery on a read-channel is disclosed to improve signal quality of an input signal and maintain a small loop latency. The timing detector selects bits within the input signal that are high quality for timing recovery and discards bits that are low quality. The selected bits are used to synchronize phase and frequency of a bit sampler with a read-back analog signal. High-pass and low-pass analysis filters may split the input signal into high-frequency and low-frequency sub-bands and equalizers may re-shape the sub-bands. High-pass and low-pass synthesis filters may construct an output signal from the high-frequency and low-frequency sub-bands. Scaling factors may correct for signal and disturbance variations in the sub-bands. A comparator may eliminate sampled bits within the detector signal that have a magnitude less than a threshold and assign a common magnitude to sampled bits that meet or exceed the threshold.

Abstract: A method is provided, which includes reading data from a data storage medium. Reading data from the medium causes the data to be erased. The method further includes determining a desired position to rewrite the data by computing a position error signal based on the data signal and compensating the position error signal for non-zero bias. The data is then rewritten non-synchronously. An apparatus is also provided, including a data storage medium with a data communication transducer configured to receive data from the medium. Data is erased after it is read. The data communication transducer is configured to rewrite the read data back onto the data storage medium in a non-synchronously. A non-zero bias compensator is provided to compensate data received by the data communication transducer to determine a desired position to rewrite the previously read data back onto the medium.

Abstract: Apparatus and method for light source power control during the writing of data to a storage medium. In accordance with various embodiments, a data recording head is provided having a magnetic transducer and a light source. The light source is driven at a first power level to irradiate an adjacent storage medium prior to the writing if data to the medium using the magnetic transducer. The first power level is insufficient to alter a magnetization state of the medium. The light source is subsequently transitioned to a higher, second power level to irradiate the storage medium during the writing of data to said medium using the magnetic transducer, the second power level being sufficient to alter said magnetization state of the medium.

Abstract: A data storage system includes recording media with a shingled track pattern of multiple data tracks in which mapped data bits are recorded. The mapped data are coherently aligned with one another across the multiple data tracks. A read head has an effective read head width that extends across the multiple data tracks and that is aligned to coherently read the mapped data bits. A read head output includes a non-binary multi-level amplitude summation of the mapped data bits.

Abstract: Techniques are described for providing media-referenced timing for operations on a data storage medium. In particular, Phase-Locked Loop (PLL) synchronization fields may be interspersed within data fields of the medium and may be read to obtain timing measurements. The PLL fields are illustratively pre-recorded at predetermined intervals on the medium and have a fixed number of dots of the bit patterned medium between the PLL fields. Phase and frequency of a write clock may be controlled based on the read PLL fields to translate the timing measurements from the PLL fields into phase and frequency corrections to synchronize the write clock to the data storage medium.

Abstract: A timing detector adapted for timing recovery on a read-channel is disclosed to improve signal quality of an input signal and maintain a small loop latency. The timing detector selects bits within the input signal that are high quality for timing recovery and discards bits that are low quality. The selected bits are used to synchronize phase and frequency of a bit sampler with a read-back analog signal. High-pass and low-pass analysis filters may split the input signal into high-frequency and low-frequency sub-bands and equalizers may re-shape the sub-bands. High-pass and low-pass synthesis filters may construct an output signal from the high-frequency and low-frequency sub-bands. Scaling factors may correct for signal and disturbance variations in the sub-bands. A comparator may eliminate sampled bits within the detector signal that have a magnitude less than a threshold and assign a common magnitude to sampled bits that meet or exceed the threshold.

Abstract: A method of determining errors in a data storage device is disclosed. The disclosed method includes receiving a first code word from the data storage device. The method further includes determining whether a data error exists in the code word by analyzing a plurality of subsequent code words. Detecting a data error includes calculating first, second, and third checksums for each of a plurality of subsequent code words and determining whether there is an insertion or deletion error based on the calculated checksums. A further method includes receiving location information of errors on a data medium and adjusting a write clock frequency to reduce the probability of creating errors on the data medium during a write process.

Abstract: A method includes: producing a bit detection signal in response to a plurality of islands located in a plurality of zones of a bit patterned media, processing the bit detection signal to produce a synchronization signal, wherein the processing is dependent on characteristics of the islands in the zone containing the plurality of islands, and using the synchronization signal to control timing of writing to the bit patterned media. The synchronization signal can also be used to control timing of reading from the bit patterned media.

Abstract: Techniques are described for providing media-referenced timing for operations on a data storage medium. In particular, Phase-Locked Loop (PLL) synchronization fields may be interspersed within data fields of the medium and may be read to obtain timing measurements. The PLL fields are illustratively pre-recorded at predetermined intervals on the medium and have a fixed number of dots of the bit patterned medium between the PLL fields.

Abstract: A write clock control system comprises a clock controller that determines a phase offset based on a phase difference between a write clock signal and a media pattern corresponding to a given timing synchronization field being read, and a phase interpolator that produces an updated write clock signal by updating the phase of the write clock signal in accordance with control signals that are based on the phase offset signal.

Abstract: A patterned recording media comprises a segment and a null pattern formed in the segment. The segment comprises first and second rows of discrete magnetic elements separated by a non-magnetic material, and a row of non-magnetic material positioned between the first and second rows. The null pattern comprises consecutive groups of the discrete magnetic elements in the first and second rows of the segment. Each group in the first row has a magnetic polarity that is opposite the magnetic polarity of adjoining groups in the first row. Each group in the second row has a magnetic polarity that is opposite the magnetic polarity of adjoining groups in the second row.

Abstract: A method is disclosed for determining position information of a transducer. At least a first code and a second code are chosen. The first code has different characteristics than the second code. User data written to a first sub-track is encoded with the first code and user data written to a second sub-track is encoded with the second code. The first code read from the first sub-track is obtained and the second code read from the second sub-track is obtained. Position information of the transducer is extracted from the obtained characteristics of the first code and the obtained characteristics of the second code.