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Parallel Servo-Track Write and Read Verification With Side-By-Side Inductive Head Elements

IP.com Disclosure Number: IPCOM000041393D
Original Publication Date: 1984-Jan-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 22K

Publishing Venue

IBM

Related People

Jones, DM: AUTHOR

Abstract

Current servo-track writing schemes usually require some sort of a verification process to insure the integrity of the resulting position error signal (PES). This verification can be performed directly over the servo track by looking at the readback quality of each written bit, or it can be performed by positioning between tracks and looking at the quality of the resulting PES. Current product servowriters use one of these two schemes with a single-element inductive head as both the write and read transducer and, therefore, must perform these operations in serial. While inline dual element heads have been proposed, these do not lend themselves easily to thin film fabrication techniques, and are not applicable when trying to read verify between servo-tracks on the composite PES.

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Parallel Servo-Track Write and Read Verification With Side-By-Side Inductive Head Elements

Current servo-track writing schemes usually require some sort of a verification process to insure the integrity of the resulting position error signal (PES). This verification can be performed directly over the servo track by looking at the readback quality of each written bit, or it can be performed by positioning between tracks and looking at the quality of the resulting PES. Current product servowriters use one of these two schemes with a single-element inductive head as both the write and read transducer and, therefore, must perform these operations in serial. While inline dual element heads have been proposed, these do not lend themselves easily to thin film fabrication techniques, and are not applicable when trying to read verify between servo-tracks on the composite PES. As shown in the figure, it is possible to fabricate two or more elements on a slider through the use of thin film technology whose centerline spacing can be very rigidly controlled. Given separate write drivers and read preamplifiers, these heads can read and write independently of each other, but on a very precise position radially in respect to each other. The centerline spacing between heads is determined by the type of verification process to be used. If TW is the desired track-to-track spacing, d is a multiple of TW for the on-track bit-by-bit verification type of process. With the other type of...