公开(公告)号：JPH03120676A

公开(公告)日：1991-05-22

申请号：JP25250889

申请日：1989-09-29

Applicant: IBM

Inventor： KISAKA MASASHI ,  MIZUNO TAKESHI

IPC: G11B21/10 ,  G11B5/55

Abstract: PURPOSE: To attain the precise followup operation of a track by generating 1st-4th detecting signals by a detection means against respective 1st-4th servo patterns passing under the head and generating a value of coefficient K by a calculation means in which the 1st-4th detecting signals are received. CONSTITUTION: The 1st and 2nd servo patterns are recorded respectively on one side and another side of a line showing the respective centers of data tracks of a rotating disk, i.e., information storage tracks, and the 3rd and 4th servo patterns are respectively recorded on one side and another side of a line separated from the center line of the data tracks. By the detection means 32-35, the 1st-4th detecting signals A-D are generated against each of the 1st-4th servo patterns passing under the head 5, then the 1st-4th detecting signals A-D are received by the calculation means 41, 42, 46 and the value of coefficient K is generated. Thus, the precise followup operation is carried out.