Dismiss
The InnovationQ application will be updated on Sunday, May 31st from 10am-noon ET. You may experience brief service interruptions during that time.
Browse Prior Art Database

Hybrid Position Error Signal Generation for Disk File

IP.com Disclosure Number: IPCOM000050556D
Original Publication Date: 1982-Nov-01
Included in the Prior Art Database: 2005-Feb-10

Publishing Venue

IBM

Related People

Authors:
Case, WJP Fraser, GB [+details]

Abstract

A head-positioning servo system for a multi-disk file derives a hybrid position error signal (PES) from continuous position information on a dedicated servo surface and from sampled intermittent position information on the data surfaces. The hybrid PES is essentially the dedicated PES adjusted, after every sample, to the value of the data PES. However, since both component position error signals represent displacement from the nearest track center and the data PES is linear over less than one track width, offsets of more than half a track between servo and data heads could result in the incorrect data track being followed. To avoid this, Gray-coded track-type information is included in the servo samples and compared with track-type information derivable from the dedicated PES to determine any necessary correction.