Browse Prior Art Database

Multielement Servoing Head

IP.com Disclosure Number: IPCOM000081932D
Original Publication Date: 1974-Sep-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 76K

Publishing Venue

IBM

Related People

McCormick, W: AUTHOR

Abstract

Read/write elements of a multitrack head accurately follow data tracks under the control of servo read elements, which detect misalignments with prerecorded servo tracks.

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Multielement Servoing Head

Read/write elements of a multitrack head accurately follow data tracks under the control of servo read elements, which detect misalignments with prerecorded servo tracks.

In Fig. 1, an axially movable head is positioned over a media such as a rotating disk, to exchange data with data tracks on the disk. The axial movement maintains registration between inductive read/write elements deposited on one side of a substrate and corresponding data tracks. Magnetoresistive (MR) servo elements deposited at right angles to the read/write elements, generate signals indicating the amount of axial movement required to maintain registration. It is assumed that the same prerecorded servo tracks control both reading and writing for a given head and disk.

In Fig. 2, many narrow servo tracks are possible because an MR element reads data when placed parallel to a track. To give an adequate number of axial head movement increments, it is desirable to have at least as many detectable servo track misalignments as there are data tracks. Given four servo tracks, sixteen unique servo read output signals can be obtained as a function of servo element to servo track positions. If either the servo tracks or (as shown in Fig. 2) the servo elements are unevenly spaced, the number of signal calibrations can be increased to eighteen.

The servo read element output signals represent axial head movement necessary to maintain registration between all the read/write elemen...