Patent ID: 7826169

Claim:
A method for detecting errors in a positional servo system of a magnetic storage drive, the method comprising: writing a first virtual track comprising a plurality of first calibration tracks; moving a write element controlled by the positional servo system for a predetermined first distance; writing a second virtual track comprising a plurality of second calibration tracks, wherein each of the second calibration tracks is adjacent to one of the first calibration tracks and overlaps with its adjacent first calibration track, such that the first calibration tracks and the second calibration tracks form a plurality pairs of overlapping first and second calibration tracks; for each pair of overlapping first and second calibration tracks, detecting a first position of the first calibration track of the pair; detecting a second position of a boundary between the first calibration track and the second calibration track of the pair; and determining a second distance between the first position and the second position; determining first errors in the positional servo system at the first positions as differences between the predetermined first distance and the second distances obtained from all the pairs of overlapping first and second calibration tracks, respectively.