Abstract: Embodiments of the invention provide techniques to inspect the track pitch of a magnetic disk. In one embodiment, the track pitch is inspected using the servo information that was written onto the magnetic disk. A PES gain is set to be PG0. A head is moved to a position K near the position where control is to switch between MPES and SPES, and then MPES and SPES are calculated using reproduced burst signals and PG0. The quantity of change in the inspection HSP which is a half-servo pitch of an inspection-related burst pattern, with respect to an ideal half-servo pitch, is detected by calculating PES?, the difference between the MPES and SPES at position K. The track pitch is thus judged whether it is abnormal.

Abstract: Servo data is stably written even if the flying height of a head/slider is varied. In one embodiment, a seamed pattern of servo data is written by a write head that is equipped in a head/slider. A variation pattern signal of the flying height in the circumferential direction of a magnetic disk is generated. The write head is located at a given position of the magnetic disk. The seamed pattern is written while controlling a recording current to flow in the write head on the basis of the variation pattern. At a constant recording current, a pattern length L1 is shortened when a flying height H1 is higher, and a pattern length L2 is lengthened when a flying height H2 is lower. The magnitude of the recording current is controlled according to the variation of the flying height, thereby making it possible to fall a pattern length L within a constant range, and accurately define the position of an edge of the seamed pattern.

Abstract: Embodiments of the invention provide techniques to inspect the track pitch of a magnetic disk. In one embodiment, the track pitch is inspected using the servo information that was written onto the magnetic disk. A PES gain is set to be PG0. A head is moved to a position K near the position where control is to switch between MPES and SPES, and then MPES and SPES are calculated using reproduced burst signals and PG0. The quantity of change in the inspection HSP which is a half-servo pitch of an inspection-related burst pattern, with respect to an ideal half-servo pitch, is detected by calculating PES?, the difference between the MPES and SPES at position K. The track pitch is thus judged whether it is abnormal.