Browse Prior Art Database

Beam Addressable Memory File

IP.com Disclosure Number: IPCOM000095036D
Original Publication Date: 1965-Aug-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 3 page(s) / 43K

Publishing Venue

IBM

Related People

Fan, GJ: AUTHOR [+2]

Abstract

This apparatus utilizes a radiant energy beam either for storing information at high density in a beam-addressable storage medium or for reading out the stored information with extreme rapidity. It is adapted especially to store files which are likely to be read much more often than they are written.

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Beam Addressable Memory File

This apparatus utilizes a radiant energy beam either for storing information at high density in a beam-addressable storage medium or for reading out the stored information with extreme rapidity. It is adapted especially to store files which are likely to be read much more often than they are written.

An example of a beam-addressable storage medium which can be used for this purpose is gadolinium iron garnet. This is transparent and has heat- sensitive magnetic properties. This material has high coercivity when it is at its magnetic compensation temperature. Such can be at or near normal room temperature. When a discrete volume of such material is heated slightly above its compensation temperature under the influence of a laser beam, for example, it loses most of its coercivity and can be magnetized by a biasing field while thus heated. The locally induced magnetism is retained by the heat spot when it cools. A stored bit can be read out nondestructively. This is effected by passing a beam of plane polarized light such as a laser beam through the bit storage position without heating the storage medium sufficiently to change its magnetic state. Then the beam passes through an optical analyzer. The value of the stored bit is indicated by either a change or lack of change in the intensity of the emerging beam. Destructive readout or erasure of the storage medium can be accomplished by heating the material sufficiently to cause, or permit, a change in its magnetic state.

The apparatus is for making effective use of beam addressable storage medium 1 to store memory files. Beam source 2, such as a laser, furnishes a polarized beam of radiant energy which passes through electro-optic deflector 3. This is adapted to deflect the beam in a direction perpendicular to the paper into any selected one of several possible posi...