Browse Prior Art Database

Preparation of Read Only Magnetic Tape

IP.com Disclosure Number: IPCOM000074934D
Original Publication Date: 1971-Jul-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Johnston, HT: AUTHOR [+2]

Abstract

A magnetic tape reading mechanism 10 reads previously recorded magnetic tape 15 and by sensing the absence of data in the inter-record gap region, utilizes this intelligence to actively destroy the recording quality of the tape in the gap. This action effectively renders the tape read-only and makes it impractical for further writing.

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Preparation of Read Only Magnetic Tape

A magnetic tape reading mechanism 10 reads previously recorded magnetic tape 15 and by sensing the absence of data in the inter-record gap region, utilizes this intelligence to actively destroy the recording quality of the tape in the gap. This action effectively renders the tape read-only and makes it impractical for further writing.

Referring to the figure, the supply reel 11,and takeup reel 12 are at opposite ends of the reading mechanism 10. The reel to be rendered read-only is mounted on the supply reel 11 and threaded onto the takeup reel 12. At the start signal, the tape is wound onto the takeup reel 12. The tape reading head 13 scans the entire width of the tape 15, sensing only the presence or absence of data. When a gap or unrecorded area is sensed by the read head 13, the associated logic and timing circuits supply a momentary pulse to a gallium arsenide laser 14. The output of the laser 14 is adjusted to destroy the recording quality of the oxide coating in the previously sensed record gap.

A mechanical hole punch or dimpling device may be substituted for the laser
14. Alternatively, the laser or mechanical device may be connected into and located on the tape writing device used to initially prepare the tape.

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