Abstract: A method of operating or calibrating a storage device having a storage medium platter includes writing servo data to the storage medium platter, where the servo data include, for each track on the storage medium platter, a servo sync mark, and a repeating pattern. For each pair of adjacent tracks on the storage medium platter, the repeating patterns, which may be orthogonal, are compared to determine relative phase of the repeating patterns on adjacent tracks. The relative phase for each pair of adjacent tracks is recorded. In another calibration method, first and second repeating patterns may compared to determine whether relative phase of the first and second repeating patterns exceeds a threshold, in which case the second servo data are erased, new second servo data are written, and the comparing and erasing are repeated until the relative phase of the first and second repeating patterns is less than the threshold.

Abstract: Systems and methods for reading data from a magnetic medium are provided. A system for reading data from a magnetic medium includes an electromagnetic head array, where the electromagnetic head array includes a plurality of read sensors. Each read sensor of the plurality of read sensors is configured to sense a magnetic field of the magnetic medium and to generate a signal based on the magnetic field. Circuitry is configured to combine the signals of the plurality of read sensors to generate a resulting signal. The resulting signal defines an effective read width of the electromagnetic head array, where the effective read width is narrower than a read width of any of the plurality of read sensors.

Abstract: The invention includes disk drive circuitry, systems, and methods. The disk drive system comprises control circuitry and a disk device. The disk device stores data and transfers an analog signal representing the data. The control circuitry receives the analog signal, converts the analog signal into a digital signal, transfers the digital signal, and biases an error signal. The control circuitry includes an analog-to-digital converter, adaptive filter, a decoder, and error signal circuitry. The analog-to-digital converter receives and samples the analog signal to generate a sampled signal. The adaptive filter shapes the sampled signal based on coefficients to produce a shaped signal. The decoder decodes the shaped signal to generate the digital signal. The error signal circuitry generates the biased error signal to adjust the coefficients in the adaptive filter.