Fault tolerant sync mark detection while servo writing a disk drive from spiral tracks

摘要

A method of writing product servo sectors to a disk of a disk drive is disclosed. The disk comprises a plurality of spiral tracks, wherein each spiral track comprises a high frequency signal interrupted at a predetermined interval by a sync mark. The read signal from the head is processed to detect a plurality of the sync marks in a spiral track crossing. A timing recovery measurement is generated in response to a selected one of the sync marks based on reliability metrics, wherein a servo write clock is synchronized in response to the timing recovery measurement. The read signal representing the high frequency signal in the spiral track crossing is processed to generate a position error signal (PES) used to maintain the head along a substantially circular target path while using the servo write clock to write product servo sectors along the circular target path.