Patent ID: 7430090

Claim:
A control device of a storage apparatus having a head which has a reading element and a recording element, is provided with a heater which varies a protrusion value by thermal expansion accompanying electric power distribution and heating, and flies above a rotating recording medium so as to access data, the control device characterized by having a preheat sector number measurement unit which, upon desired correction, measures a preheat sector number corresponding to transition time from when electric power distribution to and heating of the heater is started by predetermined preheat electric power until when a flying height is stabilized to a predetermined target flying height; and a flying height control unit which, upon reproduction or recording, distributes electric power to the heater from a sector position before a target sector by the preheat sector number so as to preliminarily heat the heater and then controls the flying height of the head to the predetermined target flying height from a target sector position; and wherein the preheat sector number measurement unit has a first mode measurement processing unit which writes test data over one track by the recording element by using a rotation reference position as a starting point in a state in which positioning to an arbitrary measurement track of the recording medium is achieved and while distribution of the preheat electric power to and heating of the heater is performed, and then reads the test data by the reading element so as to measure a predetermined evaluation value as a threshold value; and a second mode measurement processing unit which starts distribution of the preheat electric power to and heating of the heater by using the rotation reference position as a starting point, sequentially performs writing and reading of test data to or from each of sectors on the measurement track so as to measure the evaluation value in the order of the sectors, and, when the sector which satisfies the evaluation threshold value is determined, determines the number of sectors up to the determined sector as the preheat sector number.