Patent ID: 6023145
Filing Date: 2000-02-08
Classification: G11B

Abstract:
A head/disk tester having a thermal drift-compensated closed-loop positioning system for positioning a magnetic head at a desired offset with respect to a data track on a magnetic disk disposed about a disk axis, said data track extending along a circular track center line (TCL) on said magnetic disk disposed about said disk axis, comprising:A. a base;B. a spindle attached to said base, said spindle being adapted for rotatingly supporting a magnetic disk about said disk axis;C. a movable carriage supported by said base, said carriage having an assembly for supporting a magnetic head in a region overlying said magnetic disk, said magnetic head having a read element and a write element;D. positioning means for moving said carriage with said magnetic head with respect to said magnetic disk in a direction transverse to said disk axis;E. a first feedback means for determining the position of said magnetic head with respect to said data track of said magnetic disk in stable temperature conditions;F. a second feedback means for determining the position of said magnetic head with respect to said data track of said magnetic disk in varying temperature conditions, said second feedback means being responsive to servo burst signals on said magnetic disk at predetermined positions radially offset from said track center line; andG. a closed-loop positioner responsive to said first feedback means and said second feedback means to control said positioning means whereby said magnetic head is substantially at said desired offset from said track center line.