Patent ID: 6097681
Filing Date: 2000-08-01
Classification: G11B

Abstract:
An apparatus for determining the angular position of a rotatable information storage medium having substantially parallel reference tracks between which at least two information tracks are present, said apparatus comprising:means for determining a value R indicative of radial position for a read/write head for said storage medium, said value R being determined by oscillatorily moving a laser beam back and forth across an edge of reference tracks;means for determining a value V indicative of linear velocity at which bit positions on said medium move past said read/write head;processor means for determining a representation for the value of angular velocity, .omega., from V and R in accordance with the relation .omega.=V/R;clock means for determining elapsed time T since said read/write head has moved past a radially oriented reference mark on said medium; andprocessor means for determining the product .omega.T as a representation for distance along an information track.