Abstract: The present invention reduces the time required for coefficient convergence and thus improves time-to-ready. To that end, the present invention provides an initial learn—preferably non-zero—coefficient. The initial learn coefficient is based on a translation of timing information to position information. One aspect of the present invention uses address marks of a disc then translates them to phase position information. The present invention measures the times between address marks of adjacent servo sectors. Variations between those times is related is related to disc runout, particularly disc eccentricity. Also, the servo sectors are used to identify at which phase the maximum amplitude (or magnitude) of the timing variations occur. This phase information and maximum amplitude are used as variables in determining the initial learn coefficient. The present invention also utilizes a plant model to predetermine a variable.

Abstract: Using a “reference” sensor, a reference position is detected in a frame of reference that is moving along a predetermined path relative to the reference sensor. The reference position is used to derive a position-dependent indicator of a position-dependent “longitudinal” offset component (i.e. along the path). An output from the target sensor is monitored using a “target window” that is partially based on the position-dependent indicator.

Abstract: A method for determining the repeatable timing error in reclamped media is disclosed. The method allows the variation of the time intervals between servo sectors or other known locations on tracks on the disc to be determined and saved on the data storage device for later use in checking the timing during device operation. A second method for pulling write gate during data storage device operation based on known repeatable timing error data is also disclosed. This method checks the measured time intervals between sectors against an acceptable time interval range determined based on the known repeatable timing error for the disc.

Abstract: Using a “reference” sensor, a reference position is detected in a frame of reference that is moving along a predetermined path relative to the reference sensor. The reference position is used to derive a position-dependent indicator of a position-dependent “longitudinal” offset component (i.e. along the path). An output from the target sensor is monitored using a “target window” that is partially based on the position-dependent indicator.

Abstract: An embodiment of the present invention may be described as a method of determining a disc drive head position over a data surface during a head switch operation. The method includes switching from a first head located over a first data surface on one disc to a second head located over a second data surface on a different disc. Each data surface has non-index servo sectors interspersed between a plurality of index servo sectors defined thereon, and each index servo sector has a unique index code corresponding to its angular track position. The method also includes reading an index code from an index servo sector on the second surface and determining an index servo sector number from the index code. Additionally, the method includes incrementing the servo sector number as the second head encounters subsequent servo sectors. A disc drive includes data storage discs arranged in a disc stack.

Abstract: The present invention reduces the time required for coefficient convergence and thus improves time-to-ready. To that end, the present invention provides an initial learn—preferably non-zero—coefficient. The initial learn coefficient is based on a translation of timing information to position information. One aspect of the present invention uses address marks of a disc then translates them to phase position information. The present invention measures the times between address marks of adjacent servo sectors. Variations between those times is related is related to disc runout, particularly disc eccentricity. Also, the servo sectors are used to identify at which phase the maximum amplitude (or magnitude) of the timing variations occur. This phase information and maximum amplitude are used as variables in determining the initial learn coefficient. The present invention also utilizes a plant model to predetermine a variable.