Wherever disk technology has left its mark on the design of our software, it has done so for implementation purposes only, and not in the service of users or any goal-directed design rationale.

Validity of scalar diffraction theory must be checked, because the size of information mark (pit) of optical disk is comparable with or smaller than the laser wavelength.

In a hard-format, actual holes are punched on the disk, to mark the beginning of the new sector.