Abstract: Format efficiency of a hard disk of a hard disk drive having a rotary actuator and a read/write head having a read element that is offset from a write element is improved by writing a data track having a length that is based on an arc of the rotary actuator, the radial position of the read/write head with respect to the hard disk and the offset between the read element and the write element.

Abstract: A method and apparatus for determining sector block sizes using existing controller signals has been disclosed. The invention detects a characteristic of a data channel gate signal indicating a length of data, determines the length of data based on the detection of the characteristic, and calculates the size of a last data block in the length of data based on the determined length.

Abstract: Format efficiency of a hard disk of a hard disk drive having a rotary actuator and a read/write head having a read element that is offset from a write element is improved by writing a data track having a length that is based on an arc of the rotary actuator, the radial position of the read/write head with respect to the hard disk and the offset between the read element and the write element.

Abstract: A method and apparatus for determining sector block sizes using existing controller signals has been disclosed. The invention detects a characteristic of a data channel gate signal indicating a length of data, determines the length of data based on the detection of the characteristic, and calculates the size of a last data block in the length of data based on the determined length.

Abstract: A method and apparatus that adjusts FIR taps based upon Viterbi margin counts. The FIR taps are adjusted by a) selecting one of N tap pairs for adjustment, b) adjusting the tap pair up one count and down one count, c) determining whether adjusting the tap pair up or adjusting the tap pair down provides a lower Viterbi margin count from the Viterbi detector and d) selecting the tap adjustment for the pair that provides the lower Viterbi margin count.

Abstract: A method and apparatus for detecting disk drive head instability. Normal head fluctuation is removed from the criterion used to detect whether a head is unstable. The present invention accumulates error signals in an accumulator and calculates a criterion having an average fluctuation removed using the accumulated error signals. The criterion is calculated according to (max+min)−(2×average), wherein max is the maximum error signal, min is the minimum error signal and average is the average error signal. The criterion is then compared to a predetermine threshold to determine whether the head is unstable. A head is determined to be unstable when (max+min)−(2×average) is greater than the predetermined threshold.