Abstract: Improvements in placement of timing patterns in self-servowriting include correcting for random errors. Random errors may be caused by variations in disk velocity and therefore, one technique for correcting for random errors includes reducing velocity jitter. Additionally, random errors can be corrected by improving interval control during the propagation of trigger patterns used in writing timing information on storage media. Further, random errors, in the writing of timing information, can be corrected during a single revolution of the storage media. This eliminates additional rotations, thereby providing a large capital cost savings.

Abstract: Improvements in placement of timing patterns in self servo writing include correcting for random and systematic errors due to geometric effects. In a disk drive having a recording head with separate read and write elements, a method for determining separation between the elements and for correcting for such errors as a function of skew angle between the head and the disk. Errors resulting from misalignment and non-parallelism of the elements as well as misalignment of the head on it its actuator are also detected and corrected. Errors due to changes in rotational velocity of the disk and misplacement of timing patterns with respect to adjacent timing patterns are detected and corrected. In general, a single revolution process may be used to both write and detect random errors on each track and corrected on subsequent tracks.