Patent ID: 7496026

Claim:
A processor-readable medium comprising processor-executable instructions configured for: scanning a reference pattern on a disc to determine a radial position of a laser, wherein the reference pattern is located at a first nominal distance from a center of the disc and extends to a second nominal distance from the center of the disc, wherein the first and second nominal distances are accurate to within a nominal runout tolerance; and reading media ID data on the disc only when the radial position is greater than or equal to the first nominal distance plus the nominal runout tolerance and is less than or equal to the second nominal distance minus the nominal runout tolerance, wherein the scanning comprises: scanning at least a portion of a first half of the reference pattern to generate first data; calculating a first distance based on the first data; scanning at least a portion of a second half of the reference pattern to generate second data; calculating a second distance based on the second data; and averaging the first distance and the second distance to determine the distance from the center of the disc.