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Beam Addressable Drum Files

IP.com Disclosure Number: IPCOM000081413D
Original Publication Date: 1974-May-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 3 page(s) / 44K

Publishing Venue

IBM

Related People

Frost, WT: AUTHOR [+2]

Abstract

The basic arrangement provides storage of very many narrow tracks of information, for rapid access to and recording and reproduction of the information at low cost per byte.

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Beam Addressable Drum Files

The basic arrangement provides storage of very many narrow tracks of information, for rapid access to and recording and reproduction of the information at low cost per byte.

A drum is coated with a magnetic oxide, chromium dioxide, for example, which has a Curie temperature of about 125 Degrees C. The drum forms a data storage medium. A loop of magnetic tape, which may also comprise a coating of C(r)O(2) also, is arranged over the drum with the oxide coating in contact with that of the drum. The tape forms a transfer medium. Conventional means are arranged to force the tape into intimate contact with the drum. The drum is arranged as a capstan for the tape; the two are moved together without slippage for magnetic transfer from one to the other.

Thermomagnetic transfer is effected by a narrow laser beam, which affords narrow track recording on the drum from a wide track on the transfer tape and narrow track transfer from the drum to the tape.

The laser beam is arranged to heat a narrow segment on the drum to the Curie temperature, immediately prior to coming into contact with a recorded wide track on the tape loop. Cooling naturally follows--or may be aided--and data is transferred. The drum is left in a thermoremanent state with a relatively very narrow data track.

The laser is directed onto the tape for reproduction, and the relatively narrow track of data is reproduced by a conventional relatively wide track electromagnetic transducer.

An application of the basic principles is shown in schematic form. A store is constituted by a storage cylinder 10 of chromium dioxide coated magnetic tape of material transparent to a laser beam.

A transfer web 12 of chromium dioxide coated MYLAR* tape is arranged over the storage cylinder 10, with the oxide coating in beam. A transfer web 12 of chromium dioxide coated MYLAR* tape is arranged over the storage cylinder 10, with the oxide coating in contact at the top of the cylinder. The cylinder 10 and the web 12 are supported by a capstan 14, an air shoe 16 and a pinch roller 18. A conventional vacuum chamber 20 urges the web 12 into intimate contact with the cylinder 10. The air shoe 16 furnishes the major effort in maintaining intimate contact. Another pinch roller 24 and another capstan 28 cooperate with the capstan 14 and the pinch roller 18, respectively, for driving the cylinder 10 and web 12 in intimate contact without slipping. The pinch rollers and the capstans are cooled when necessary.

Electromagnetic transducers 30, 32 and 34 of conventional form are arranged for recording/reproducing and erasing. The transducer 30 of conventional form is used to record information on the web 12 in...