Patent ID: 8085492
Filing Date: 2011-12-27
Classification: G11B

Abstract:
1. A method comprising: receiving a waveform produced by a head operated with respect to a rotating magnetic recording medium, which comprises helicoid patterns arranged in a first helicoid group and a second helicoid group, the first helicoid group being different than the second helicoid group; determining, based on the waveform, one or more first phase differences corresponding to the first helicoid group; affecting an alignment of the head with respect to the recording medium based on the first helicoid group by compensating for the one or more first phase differences to maintain the alignment; determining, while compensating for the one or more first phase differences, one or more second phase differences corresponding to the second helicoid group; and affecting, responsive to a switch from the first helicoid group to the second helicoid group, the alignment of the head with respect to the recording medium by compensating for the one or more second phase differences to maintain the alignment.