Patent ID: 7251908

Claim:
A magnetic disk drive comprising: a magnetic disk medium; a spindle motor for rotating said magnetic disk medium at a constant speed; a magnetoresistive head using a magnetoresistive element as an element for reading out data from said magnetic disk medium; and a carriage configured to position said magnetoresistive head at a desired track on said magnetic disk medium; wherein said magnetic disk drive further includes a table in which, in specific regions of said magnetic disk medium, several tracks internal/external to thermal asperity (TA) causing sections of said magnetic disk medium, in a radial direction thereof, and several bytes of space or several sectors in front of and at rear of the TA-causing sections, in a circumferential direction of said magnetic disk medium, are registered collectively as a primary defect region (primary registration), and then, tracks within a range wider than a range of the primary registration, and all sectors in a circumferential direction of the tracks, are registered collectively as a secondary defect region (secondary registration).