Browse Prior Art Database

Integrated Micro VCM Lock as Write Inhibit Generator

IP.com Disclosure Number: IPCOM000108980D
Original Publication Date: 1992-Jul-01
Included in the Prior Art Database: 2005-Mar-23
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Sri-Jayantha, M: AUTHOR

Abstract

For laptop DASD applications, it is important to detect angular motion in order to provide improved shock and vibration protection during operating conditions. The position of the head when between sectors is typically not known in a sector servo-based DASD. External shock can result in data overwrite problems on neighboring tracks. Angular acceleration in the case of a well-balanced rotary actuator is the fundamental contributor to this failure mode.

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Integrated Micro VCM Lock as Write Inhibit Generator

       For laptop DASD applications, it is important to detect
angular motion in order to provide improved shock and vibration
protection during operating conditions.  The position of the head
when between sectors is typically not known in a sector servo-based
DASD.  External shock can result in data overwrite problems on
neighboring tracks.  Angular acceleration in the case of a
well-balanced rotary actuator is the fundamental contributor to this
failure mode.

      Detection of angular shock during a write operation is achieved
by generating an "instantaneous" write inhibit signal during
open-loop or closed-loop operation of a Micro-VCM as shown in the
figure.  The same Micro-VCM device is used as an actuator lock to
reduce effective cost.  The back EMF of the Micro-VCM is used to
generate the write inhibit signal.  To remove friction at the pivot,
the mass-balanced Micro-VCM can be supported flexurally and it
resonance mode can be filtered or enhanced to detect external shock
or transient vibration.