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Recording Medium With Discrete Alternate Track of Differing Coercive Force

IP.com Disclosure Number: IPCOM000089796D
Original Publication Date: 1977-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 22K

Publishing Venue

IBM

Related People

Hoagland, AS: AUTHOR

Abstract

As shown in the figure, alternate tracks of differing coercive force magnetic material are used for servo and data information. The high coercive force tracks are used for servo information. Suitable signals would be first recorded on these tracks. The low coercive force tracks are used for data. This system is useful for either tape or disk media.

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Recording Medium With Discrete Alternate Track of Differing Coercive Force

As shown in the figure, alternate tracks of differing coercive force magnetic material are used for servo and data information. The high coercive force tracks are used for servo information. Suitable signals would be first recorded on these tracks. The low coercive force tracks are used for data. This system is useful for either tape or disk media.

Insofar as data reading and writing are concerned, because of the different coercive forces, the data performance is the same as if the intervening tracks were nonmagnetic. The difference is that on both writing and reading of the data signals, the recorded servo signals of a lower frequency, for instance, are sensed and used to accurately control the head position. The write current for the data recording head must be such that only the lower coercive force media is affected and not the higher coercivity of the servo tracks. Any of the well known methods such as a dual-element head or differing frequencies between data and servo may be used to accomplish the position sensing.

The different coercivity tracks may be formed by filling alternate grooves in a substrate with magnetic particulate material of different coercivity, or thin-film metallic layers can be deposited through appropriate masks to produce differing magnetic layers.

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