The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 10, 1990
Filed:
Aug. 10, 1988
Applicant:
Inventor:
David M Oldham, Tucson, AZ (US);
Assignee:
International Business Machines Corporation, Armonk, NY (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ; G11B / ;
U.S. Cl.
CPC ...
369 13 ; 360131 ; 369 47 ; 369 48 ;
Abstract
In a magnetooptic record member the erasure direction for successive recording areas (sectors) are determined by the direction of magnetization of prior recording. A mark is placed in each sector for identifying its erasure direction. The mark is preferably a sequence of longer ones, of one-half wavelengths appearing in the recorded information-bearing signals. The erasure and recording directions are reversed such that in the recording direction in a successive recording area equal to the erasure direction of a proceeding area. This selection is based upon the current direction of a magnetic steering field.