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Browse Prior Art Database

Method to Predict Data Head Mis-Registration in Recording Devices with Dedicated Servo Surface

IP.com Disclosure Number: IPCOM000108556D
Original Publication Date: 1992-Jun-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 3 page(s) / 109K

Publishing Venue

IBM

Related People

Harris, WL: AUTHOR [+3]

Abstract

Disclosed is a method to extract positional information from data heads in storage devices. This is done with no reduction of storage capacity.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Method to Predict Data Head Mis-Registration in Recording Devices with Dedicated Servo Surface

       Disclosed is a method to extract positional information
from data heads in storage devices.  This is done with no reduction
of storage capacity.

      Most data storage devices utilize a dedicated servo zone, on
one of the recording surfaces, to position the data heads.  As data
track densities have increased, so has the risk of over-writing
adjacent tracks when the data heads do not precisely follow the servo
head.  Refer to Fig. 1 for an example of this.  Data head position,
when factored into servo control, prevents adjacent track over-write.

      This method processes the "variable gain amplifier" (VGA)
control signal found in the read channel.  The resultant of this
process provides an indicator when selected data head(s) are not
positioned closely enough to track center to permit a "data write"
operation.  This indicator will be called "Data Head Write Inhibit"
(DHWI) for purposes of this document.  Refer to Fig. 2.

      There are two methods contained in this disclosure to generate
"DHWI".  The first uses hardware, consisting of a buffer amplifier,
bandpass filter, and comparator.  The bandpass filter's response can
be tailored to accentuate a frequency range that has proven to be
troublesome for the storage device being protected.  The filter also
removes any DC component to allow the comparator to work according to
a zero- volt center.  The comparator output, a unipolar...