Patent ID: 8031421
Filing Date: 2011-10-04
Classification: G11B

Abstract:
1. In a seeking time measurement process in which, in order to inspect a magnetic head or a magnetic disk, the magnetic head is actuated to seek a track segmented into sectors on the magnetic disk, test data is written to the track and the test data is then read from the track, and a settling time until vibration of the magnetic head attenuates or a seeking time including the settling time is measured, a method for measuring an optimum seeking time taking the settling time of the magnetic head into account, the method comprising: calculating the seeking time to be taken for a seek from a given track or a head load position to a target track, actuating the magnetic head to seek the target track in compliance with the seeking time, and writing the test data to the target track after the seeking time; reading the written test data from the target track, detecting sector-wise average levels of the test data read levels in positive and negative domains respectively, and sampling a waveform of the average levels for one round of track; and detecting a maximum value H and a minimum value L among peak-to-peak amplitudes in the sampled waveform for one round of track, further calculating a deviation DEV of the average levels by an equation, DEV=(H−L)/(H+L), DEV=(H−L)/H, or DEV=(H−L)/L, where DEV is a deviation of the average levels, and judging whether the deviation DEV of the average levels is equal to or less than a predetermined value or exceeds the predetermined value; wherein the predetermined value corresponds to the deviation DEV of the average levels calculated by the selected equation, when a seeking time is set including the settling time that is equal to or more than a maximum time of settling that the magnetic head is settled during the seek to the target track, and wherein the method further comprises calculating the seeking time while changing the settling time and, after writing and reading the test data, obtaining, as an optimum seeking time, a minimum value of seeking time equal to or less than the predetermined value obtained by the judgment or obtaining, as an optimum settling time, a value of settling time when the minimum value of seeking time is obtained.