Browse Prior Art Database

Batch Fabricated Tunnel Erase Head

IP.com Disclosure Number: IPCOM000078214D
Original Publication Date: 1972-Nov-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Davy, JC: AUTHOR

Abstract

When previously recorded data on a medium such as a disk file is overwritten, thermal effects and/or mechanical tolerances can result in a slight misregistration of the recording head with a previously recorded track. Thus, parts of the old data may be unerased by the new and will be detected as noise on subsequent reading.

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Batch Fabricated Tunnel Erase Head

When previously recorded data on a medium such as a disk file is overwritten, thermal effects and/or mechanical tolerances can result in a slight misregistration of the recording head with a previously recorded track. Thus, parts of the old data may be unerased by the new and will be detected as noise on subsequent reading.

Fig. 1 shows an exploded view of a multitrack head having a tunnel erase feature designed to overcome this problem. Each copper strip 1, deposited on a ferrite substrate 2, constitutes a pair of single-turn windings for a respective pair of read/write transducers.

The magnetic yoke for each transducer is formed by the common ferrite block 2 and one of the individual permalloy elements 3.

Further pairs of permalloy elements 4 and 5 have a common-erase conductor 6 sandwiched between them.

Referring to Fig. 2, each read/write transducer writes a track of width a, as determined by the width of permalloy elements 3. Concurrently, erase winding 6 is energized so that portions of the medium lying under permalloy erase element pairs 4 and 5 are erased. This trims down the written track to width b- the tunnel erase principle. Because the erase winding is common, each track covered by the head will be trimmed on every writing operation, irrespective of whether that track itself is being rewritten. Thus, in practice, the slight misregistration likely to arise over a number of writing operations will cause the tracks to...