Patent ID: 8363347

Claim:
A storage device comprising: a disk comprising a first pattern formed in a radial direction of the disk on at least one of an inner area and an outer area of the disk, and a second pattern formed obliquely to the radial direction; a detector configured to detect the first pattern and the second pattern on a track traversing the first pattern and the second pattern on the disk; a counter configured to count number of the detected first pattern until the count value reaches number of the first pattern in one round of the track; a generator configured to generate a value incremented until the value reaches a maximum pattern number that is number of the second pattern in one round of the track every time an interrupt is generated in association with detection of the second pattern as number of the second pattern detected by the detector; a calculator configured to calculate an ideal number based on a multiplied value and a radial direction reference number, wherein the multiplied value is obtained by multiplying the number of the second pattern detected until the number is counted by the counter by the counted number of the detected first pattern, and the radial direction reference number is set to the second pattern formed in the radial direction of the disk with reference to the second pattern formed at a preset initial position; and a corrector configured to correct the generated number with the calculated ideal number if the generated number is not identical to the calculated ideal number.