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And now--the erasable videodisk

Library Systems Newsletter [November 1982]


A videodisk that can be erased and rerecorded has been announced by the Japan Broadcasting Corp. (Tokyo), thus overcoming a major limitation of current videodisk systems. The Japanese prototype uses a helium-neon laser to write data on a disk coated with a magnetic film of amorphous gadolinium and cobalt. Data is recorded when the heat from the laser beam causes local reversals of the film's magnetic field. New data can be written over old data, or the entire disk can be erased by bathing it in a strong magnetic field. In contrast, conventional systems do now allow rerecording or erasure because the laser in these systems punches holes--representing data--in the disk coating. The erasable system, which also uses a laser to read data via an optomagnetic effect, needs further development to overcome a low signal-to-noise ratio and disk coating imperfections that cause data loss.

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Publication Year:1982
Type of Material:Article
Language English
Published in: Library Systems Newsletter
Publication Info:Volume 2 Number 11
Issue:November 1982
Page(s):85-86
Publisher:American Library Association
Place of Publication:Chicago, IL
Notes:Howard S. White, Editor-in-Chief; Richard W. Boss, Contributing Editor
Subject: Videodisk technology
ISSN:0277-0288
Record Number:3885
Last Update:2021-11-17 12:27:41
Date Created:0000-00-00 00:00:00