Browse Prior Art Database

Thermomagnetic Recording and Erasure

IP.com Disclosure Number: IPCOM000078607D
Original Publication Date: 1973-Feb-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Frost, WT: AUTHOR [+2]

Abstract

This arrangement provides a direct access beam-addressable magnetic record file, in which previously recorded information is erased and new information rewritten almost simultaneously, with negligible loss in data throughput.

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Thermomagnetic Recording and Erasure

This arrangement provides a direct access beam-addressable magnetic record file, in which previously recorded information is erased and new information rewritten almost simultaneously, with negligible loss in data throughput.

The arrangement 10 comprises a magnetic record carrier shown here as a length of magnetic tape 12 and an electromagnet 14. Not shown is apparatus for projecting two light beams 22 and 24 between the pole pieces 16, 18 of the electromagnet 14. The tape 12 travels in the direction of the arrow 26, which direction is also perpendicular to that defined by the two light beams 22 and 24. Preferably the light beams are generated by semiconductor lasers or other lasers capable of being modulated. The beams 22 and 24 are focused onto the track between the pole pieces of the electromagnet 14, such that the beam 22 is within a predominately perpendicular magnetic field of one polarity and the beam 24 is within a predominately perpendicular field of the opposite polarity.

To record in a track, the light beams are projected onto the surface of the tape 12 under the influence of the magnetic field from the head 14. The light beam 22 is unmodulated so that the magnetic field associated with it saturates the magnetic medium in one direction. The other light beam 24 is modulated by the data to be recorded and operates thermally with the magnetic field of opposite polarity right on the tape 12. To read a track, only the be...