Method and system for write clock synchronization in a data storage system

摘要

A method for synchronizing newly recorded data with previously recorded data. The method is implemented within a disk-based data storage system. A first difference between a wobble reference signal and previously recorded data is measured. Test data is written on a test track to measure a second difference between the wobble reference signal and the test data. The test data is written synchronously with a write clock. An offset value is determined by comparing the first difference and the second difference. New data is then written using the write clock and the offset value such that the new data is synchronized with the old data. To determine the offset value, the test data can be written to the test track with a write clock calibration delay set to zero, the test data can then be read from the test track and the first difference can be subtracted from the second difference to determine the offset value for the write clock calibration delay. A delay offset can be inserted into a wobble-to-laser path to cause the new data to have the same epoch as the previously recorded data. An error value can be checked to determine whether the error value is within predetermined limits, wherein the error value is the difference between the first difference and the second difference. The write clock can be adjusted in accordance with the error value if the error value is outside the predetermined limits.