Servo writing a disk drive by writing multi-bit sync marks in spiral tracks for improved servo writing

A method of writing spiral tracks on a disk of a disk drive is disclosed. The disk drive comprises control circuitry and a head disk assembly (HDA) comprising the disk, an actuator arm, a head coupled to a distal end of the actuator arm, and a voice coil motor for rotating the actuator arm about a pivot to position the head radially over the disk. A write clock is synchronized to the rotation of the disk, and a plurality of spiral tracks are written on the disk at a predetermined circular location determined from the write clock. Each spiral track comprises a high frequency signal interrupted at a predetermined interval by a multi-bit sync mark, and each multi-bit sync mark comprises a plurality of bits.