Browse Prior Art Database

Optical Substrate Format for Track Density Doubling

IP.com Disclosure Number: IPCOM000121189D
Original Publication Date: 1991-Jul-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 1 page(s) / 30K

Publishing Venue

IBM

Related People

Karis, T: AUTHOR [+3]

Abstract

Disclosed is a means for providing track and sector identification in a bi-planar recording configuration in optical data storage. Instead of encoding every single groove and land with unique track sector patterns, typically done by embossing, identical track identification marks can be assigned to each land/groove pair. Data tracks on lands can be distinguished from those on grooves by the polarity of the track error signal (TES) slope by using a bi-polar slope track servo algorithm.

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Optical Substrate Format for Track Density Doubling

      Disclosed is a means for providing track and sector
identification in a bi-planar recording configuration in optical data
storage.  Instead of encoding every single groove and land with
unique track sector patterns, typically done by embossing, identical
track identification marks can be assigned to each land/groove pair.
Data tracks on lands can be distinguished from those on grooves by
the polarity of the track error signal (TES) slope by using a
bi-polar slope track servo algorithm.

      For example, in a format where lands are identified by even
numbers and grooves by odd numbers, only even track numbers need to
be embossed.  During sector ID detection the software will recognize
tracks to be on lands when the TES slope polarity is positive.
Negative TES slopes indicate tracks located on grooves.  By adding
one to the even tracks-on-lands number, adjacent tracks on grooves
are uniquely identified.  This can be easily implemented in
microcode.

      Disclosed anonymously.