FIFTH EDITION
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`
`The Complete Illustrated Desk Reference
`
`
`
`0001
`0001
`
`TDA 1024
`TDA 1024
`CBM of U.S. Pat. No. 7,533,056
`CBM of US. Pat. No. 7,533,056
`
`

`

`This book is available at a special discount when ordered in bulk
`quantities. For information, contact Special Sales Department,
`AMACOM, a division of American Management Association,
`135 West 50th Street, New York, NY 10020.
`
`This publication is designed to provide accurate and authoritative information in
`regard to the subject matter covered. It is sold with the understanding that the
`publisher is not engaged in rendering legal, accounting, or other professional service.
`If legal advice or other expert assistance is required, the services of a competent
`professional person should be sought.
`
`Library of Congress Cataloging-in-Publication Data
`
`the complete illustrated desk reference /
`
`Freedman, Alan, 1942-
`The computer glossary :
`Alan Freedman. —— 51h ed.
`p.
`cm.
`ISBN 0—8144—5020-2 (hard). —— ISBN 0-8‘144—7749-6 (pbk.)
`1. Computers~—D1ctionaries.
`2. Electronic data processing-
`—Dicrionaries.
`I. Title.
`OA7G.15.F734
`1991
`004‘ .03~—-dc20
`
`‘
`
`904269CIP
`
`© 1991, 1989, 1983, 1981
`The Computer Language Company Inc.
`All rights reserved.
`Printed in the United States of America.
`
`Previous editions were published by PrenticevHall and
`The Computer Language Company Inc.
`
`This publication may not be reproduced, stored in a retrieval system,
`or transmitted in whole or in part, in any form or by any means, electronic,
`mechanical, photocopying, recording, or otherwise, without the prior written
`permission of AMACOM, a division of American Management Association,
`135 West 50 Street, New York, NY 10020.
`
`Printing number.
`
`10987654321
`
`
`
`0002
`0002
`
`

`

`he alternatives in a
`
`f
`.1
`h
`t e ree S O tape
`
`.
`
`ment that defines
`rte an executable
`
`Equipment
`[need in 1981,
`
`
`DECsystem
`(l) A series of RISC—based, 32-bit computers from Digital Equipment
`
`Corporation that run under ULTRIX. Introduced in 1989, the 5400 model is a
`
`Q—bus system; the 5800 model uses the XMI bus.
`
`
`(2) A series of mainframes from Digital that were introduced from 1974 through
`
`1980 and were the successor to the 36-bit PDPle computers.
`
`
`DECtalk A voice synthesizing system from Digital Equipment Corporation
`
`that accepts serial ASCII text and converts it into audible speech. It is used in
`
`Touch—tone telephone response systems as well as for voice‘output for visually
`
`handicapped users.
`
`
`dedicated Channel A computer channel or communications line that
`is used for one purpose.
`
`
`dedicated service A service that is not shared by other users or
`related products from
`.
`.
`organizations.
`
`iemebstyle local area
`broadband, private
`dEfaUIt A standard setting or action taken by hardware or software if the
`mnection of PDP and
`31s as well as PCs and
`user has not specified otherwise. For example, defaults in word processing
`
`programs define the margins, tabs and page length, all of which can be changed
`ng system.
`
`by the user.
`:ocessing machine and not
`
`
`at converts a coded
`
`er forms while
`
`; original size.
`
`.ber. Decrementing a
`current value.
`
`gital Equipment
`DECstation 3100 and
`
`3n 200 and 300),
`
`78, that was used
`
`
`defragment To reorganize the disk by putting files back into a contiguous
`order.
`
`
`degausser A device that removes unwanted magnetism from a monitor
`
`or the read/write head in a disk or tape drive.
`
`
`DEL key (DELete key) A keyboard
`
`lrey used to delete the character under the
`
`screen cursor or some other block of data.
`It is often used in combination with the
`
`shift, control and alt keys to delete various
`
`text segments.
`
`
`
`
`
`delay line A communications or
`
`electronic circuit that has a builtrin delay. Acoustic delay lines were used to
`create the earliest computer memories. For example, the UNIVAC I used tubes
`
`of liquid mercury that would 510w down the digital pulses long enough (a fraction
`of a second) to serve as storage.
`
`delete To remove an item of data from a file or to remove a file from the
`disk. See undelete.
`
`
`
`The Computer Glossary
`
`The Computer Glossary
`
`17 5
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`0003
`0003
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