Browse Prior Art Database

Bubble Domain Sensor Arrays for Magnetic Discs

IP.com Disclosure Number: IPCOM000075960D
Original Publication Date: 1971-Dec-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 3 page(s) / 40K

Publishing Venue

IBM

Related People

Chang, H: AUTHOR [+2]

Abstract

For fixed-head magnetic files, many detection heads are required which are preferably fabricated by batch techniques. It is also desirable to provide a selection matrix to enable the detection heads to share sense amplifiers. A bubble domain sensor array which fulfills these requirements, is shown in the embodiments of Figs. 1 and 2.

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Bubble Domain Sensor Arrays for Magnetic Discs

For fixed-head magnetic files, many detection heads are required which are preferably fabricated by batch techniques. It is also desirable to provide a selection matrix to enable the detection heads to share sense amplifiers. A bubble domain sensor array which fulfills these requirements, is shown in the embodiments of Figs. 1 and 2.

In Fig. 1, a magnetic disc has recording tracks located thereon and is rotated in the direction of the arrow. Located above the disc is a magnetic chip 10 which contains the bubble domain sensor array. The array comprises a plurality of domain generators, a selection matrix associated with the various propagation paths, and domain busters which collapse domains in sheet 10. The domains travel toward the domain busters and reach the busters, if no stray magnetic fields are present in the proper bit positions of the magnetic discs. If a stray magnetic field is present in a bit position, the domain located over that bit position will be deflected to the left and will be propagated to the detector and sense amplifier. Consequently, a plurality of OR switches are provided above the bit locations in the disc tracks and the domains are selectively deflected to the detector, depending upon the data on the magnetic disc.

The time interval between successive domains on each propagation path is the same as the time interval between successive discs on each recording track. All forward paths of the domains (paths) leading to the domain busters) are organized into a selection matrix, so that N control lines can be used to select 1 out 2/N/ paths. This feature is described in an article by H. Chang et al, in the Proceedings of the International Solid State Circuits Conference, Phila, Penn., 1971, Page 86.

The forward paths need two propagation channels, while the return path to the detector needs one propagation channel. Approximately 10 bubble diameters is the width required pe...