Patent ID: 8345370
Filing Date: 2013-01-01
Classification: G11B

Abstract:
1. A magnetic disk drive comprising: a grouping module configured to partition a set of tracks on a disk into a plurality of groups and configured to partition each of the plurality of groups into a plurality of subgroups, each of the plurality of groups comprising a plurality of tracks including at least two tracks with nonconsecutive physical positions and each of the plurality of subgroups comprising at least one track; a bitmap comprising, for each of the plurality of groups, a set of bits indicating whether or not any write has been executed on each of the plurality of subgroups; a write management module configured to count a write count for each of the plurality of groups and configured to manage, using the bitmap for each of the plurality of groups, whether or not any write has been executed on each of the plurality of subgroups in the group; and a refresh controller configured to exclude from the refresh targets, based on the bitmap corresponding to a group to be refreshed, a subgroup of the plurality of subgroups in the group to be refreshed on which no write has been executed when the refresh controller executes refresh process for the group to be refreshed, the group to be refreshed being a group of the plurality of groups for which the write count exceeds a threshold.