DISTRIBUTION OF CLOCK INDICIA FOR A QUASI-CONSTANT LINEAR-VELOCITY DISK

摘要

A disk (10) (magnetic, magneto-optical or optical) includes information-bearing tracks (12) having prerecorded indicia, preferably tracking pads (30), distributed uniformly along each track for phase locking a write clock (55) so as to write user data subsequently between the tracking pads, in the presence of random fluctuations in disk speed. The tracks are grouped into a plurality of annular zones (16) encircling the center of the disk, wherein the ratio of the inner radius (or outer radius) of a given zone to the corresponding radius of the adjacent inner zone is a rational number, n/d, which is the same for each adjacent pair of zones. Each track within a given zone, i, has a fixed number of radially aligned tracking pads, Pi, calculated from: Pi = (n/d)?i-1 x (d)N-1¿ where i is 1 for the innermost zone and is N for the outermost zone.