Abstract:
A storage system includes a storage medium operable to maintain a data set, a read/write head assembly operable to write the data set to the storage medium and to read the data set from the storage medium, a multi-level encoder operable to encode the data set at a plurality of different code rates before it is written to the storage medium, and a multi-level decoder operable to decode the data set retrieved from the storage medium and to apply decoded values encoded at a lower code rate when decoding values encoded at a higher code rate.
Abstract:
A servo system includes a detector circuit operable to apply a data detection algorithm to digital data to yield hard decisions, a convolution circuit operable to yield ideal digital data based on the hard decisions and on target values, a subtraction circuit operable to subtract the ideal digital data from the digital data to yield an error signal, a scaling circuit operable to scale the error signal to yield a scaled noise signal, an adder operable to add the scaled noise signal to the digital data to yield noise-added digital data, and a second detector circuit operable to apply a second data detection algorithm to the noise-added digital data to yield output hard decisions.
Abstract:
A hard disk drive or other storage device comprises a storage medium, a read/write head, and read channel circuitry coupled to the read/write head. The read channel circuitry comprises a despreader configured to generate a stitched logic sector by stitching together subsectors of that logic sector that were interleaved with subsectors of other logic sectors for storage on the storage medium, and a subsector bridging control module configured to control a number of bridging bits inserted by the despreader between a given pair of adjacent subsectors of the stitched logic sector. The subsector bridging control module may be illustratively configured to cause the despreader to insert a sufficient number of bridging bits between each pair of adjacent subsectors of the stitched logic sector so as to prevent discontinuities that might otherwise arise from use of X-averaging in generation of Y samples from X samples in a retry mode of operation.
Abstract:
The present inventions are related to systems and methods for data processing, and more particularly to systems and methods for priority based data processing.
Abstract:
A data processing circuit includes a subtraction circuit operable to subtract an ideal version of a data pattern from a sampled version of a data pattern to yield a difference signal, an error calculation circuit operable to calculate an error between the ideal version of the data pattern and the sampled version of the data pattern based on the difference signal, and a comparator circuit operable to compare the error with a threshold value and operable to assert a track refresh signal if the error is greater than the threshold value. The track refresh signal is operable to trigger a magnetic storage device to refresh data on a data track.
Abstract:
Servo channel noise limits are defined through Viterbi decisions based on servo gate signals. Y values are used to produce a first Viterbi decision at each servo gate. Viterbi decisions and Y values are used to produce ideal Y values. Y values and ideal Y values are used to produce an error value which is adjusted by a noise factor based on estimated channel characteristics. The noise value is combined with Y values and used to produce a second Viterbi decision at each servo gate.