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:
Oct. 06, 1992
Filed:
Mar. 01, 1991
Michael D Sidman, Colorado Springs, CO (US);
Digital Equipment Corporation, Maynard, MA (US);
Abstract
A magnetic disk drive having a dedicated servo surface containing circular tracks of dedicated servo signals and data surfaces containing circular data tracks divided into sectors each of which includes a data field and a servo field containing embedded servo signals, a dedicated servo signal sensor for sensing servo signals on said dedicated surface, an embedded signal sensor for sensing embedded servo signals on a data surface and a head positioning system for positioning a read/write head over a selected data track. The dedicated servo tracks comprise successive groups of four tracks, each of a different track type, and the dedicated servo signals are recorded in circumferential positions according to the track types of the tracks. The dedicated signal sensor spans two dedicated servo tracks and its output is linearly related to the radial position of said servo signal sensor relative to the track containing the corresponding recorded servo signal. The servo fields in the data tracks contain first and second embedded servo signals of substantially constant amplitude high-frequency bursts on alternate sides of the track centerlines. The embedded servo signals are written by using the read/write head displaced one half track radially with respect to the track centerlines according to position signals provided by combinations of the dedicated servo signals corresponding to different track types.