Abstract: A process of writing sector header data in the form of a stream of digital bits producing features located at varying radial positions on a master recording disk. Synchronized with rotation of the disk, a variable delay having a duration which varies with the radial positions of the bits on the disk is introduced into a clock signal. In the preferred embodiment, using the clock signal, a highly accurate, variable time delay is generated between the rotation of a master recording spindle and the recording of sector header data on a master disk mounted on the spindle. Thus, optical disks manufactured from the master disk have arc-shaped sector header spokes exhibiting maximum spatial accuracy and resultant maximal timing accuracy.