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:
Jun. 28, 1983
Filed:
Nov. 12, 1980
Friedrich R Hertrich, Boulder, CO (US);
Slobodan R Perera, Boulder, CO (US);
Digital Equipment Corporation, Maynard, MA (US);
Abstract
A transducer positioning system and a magnetic disk therefor for use in a disk drive unit of a data processing system. The magnetic disk contains plural servo sectors interposed between a plurality of circumferentially spaced data sectors. Each servo sector contains at least two sets of spaced servo blocks that include first and second asymmetrical, time-displaced, complementary servo information signals located in radially adjacent blocks. Respective sets of data track centerlines are aligned with the phase boundaries of an associated set of servo blocks in the servo sector. The disk drive unit includes a controller that selects one of the servo blocks and use a null detector to position a movable transducer over a data track centerline associated with the set of phase boundaries of the selected servo block. The controller additionally includes a track difference counter responsive to the null detector thereby to count zero crossings of the phase boundaries during movement of the transducer for indicating the displacement between the movable transducer and the desired data track in the data sector and for controlling the movement of the transducer.