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Tape Guard Band Reduction for High Track Density Storage

IP.com Disclosure Number: IPCOM000034760D
Original Publication Date: 1989-Apr-01
Included in the Prior Art Database: 2005-Jan-27
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Cannon, MR: AUTHOR

Abstract

In high track density magnetic storage systems, manufacturing tolerances, tape interchange, and thermal and hydroscopic variations all cause track misalignment of a multitrack tape format. A write wide/read narrow tape format provides unused tape guard bands to accommodate these misalignments. At high track densities, the guard bands are a significant portion of the available tape surface. Consequently, it is desirable to reduce the guard bands. Currently, servo systems are commonly used to properly align a head to the recorded tracks on disks. Most servo techniques require a preformatted recording surface. However, advanced storage systems must also be designed to accommodate nonformatted 3480 tapes. A technique is described which allows an advanced machine to write a servo burst at beginning of tape.

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Tape Guard Band Reduction for High Track Density Storage

In high track density magnetic storage systems, manufacturing tolerances, tape interchange, and thermal and hydroscopic variations all cause track misalignment of a multitrack tape format. A write wide/read narrow tape format provides unused tape guard bands to accommodate these misalignments. At high track densities, the guard bands are a significant portion of the available tape surface. Consequently, it is desirable to reduce the guard bands. Currently, servo systems are commonly used to properly align a head to the recorded tracks on disks. Most servo techniques require a preformatted recording surface. However, advanced storage systems must also be designed to accommodate nonformatted 3480 tapes. A technique is described which allows an advanced machine to write a servo burst at beginning of tape. Either an unused tape or a used 3480 tape will accept the servo burst on the initial advanced machine pass. All subsequent passes of the tape on any advanced machine will allow the head to be aligned to the tape format. Consequently, the fixed manufacturing tolerances are removed and only the variable tolerances remain. Even one-half of the tape dimensional variation can be removed if the servo burst is positioned near the center of the tape. Advanced machines will likely include a mechanical head positioner, so only the servo detector cost is added. The advanced machine guard band can then be reduced from 13...