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Re-Recordable Servo System for Multi-Track Tape

IP.com Disclosure Number: IPCOM000049798D
Original Publication Date: 1982-Jul-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Schwarz, TA: AUTHOR

Abstract

A servo system is provided for guiding a recording/readback head to a referenced position on a magnetic tape, or vice versa. The build-up of mechanical tolerances to the reference plane in a tape drive limits the possibilities of significantly increasing track densities. Servo techniques uncouple head-track positioning from these tight mechanical tolerances.

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Re-Recordable Servo System for Multi-Track Tape

A servo system is provided for guiding a recording/readback head to a referenced position on a magnetic tape, or vice versa. The build-up of mechanical tolerances to the reference plane in a tape drive limits the possibilities of significantly increasing track densities. Servo techniques uncouple head-track positioning from these tight mechanical tolerances.

In the present system, when data is recorded, initially or after the media has been erased (degaussed), a servo track is written while the data tracks are being simultaneously written. During this phase, the head to tape position is controlled except for the present mechnical constraints. The head remains within a recording band on the media, slightly wider (head width plus tolerances) than the head width.

On subsequent reads or updates of previously recorded data, the head/tape Is steered from this servo track using normal position error signal techniques and feedback control techniques on the head or media. During subsequent writes (new region) on the previously partially recorded tape, the head/tape is guided into the new region from the previously written servo track before guidance is released. In this manner, violent transitions in the servo track are avoided.

The recording/readback head incorporates, in addition to the normal data read and write elements, a pair of adjacent servo track write elements and a servo read element, as shown in Fig. 1. Fig. 1a shows the servo elements adjacent a group of data tracks, while...