POSITIONING METHOD FOR MAGNETIC HEAD

摘要

PURPOSE:To attain the positioning of a magnetic head in small correcting frequencies and to shorten the access time by reading and storing previously the eccentric amount of a floppy disk and positioning the magnetic head in accordance with the eccentricity of the floppy disk when the magnetic head is shifted to a desired track. CONSTITUTION:Servo information is previously recorded on each sector of each track of a medium 1 and the eccentric amounts of one or several tracks are read and stored when the medium 1 is changed or when a fixed period of time passed with no change of the medium 1. A microprocessing unit 10 storing the position shift information always monitors the time sent from an index signal when the unit 10 shifts a magnetic head 3 to a desired track. Then the unit 10 decides the time point when the head 3 is settled from the index signal after the head 3 is shifted and then calculates the present sector position from said time point. Thus an actuator 4 is started based on the profile of the eccentric amount of the medium 1 that is read out previously.