THE
`H/ARPERCOLLINS
`/ DICTIONARY
`
`OF
`
`COMPUTER
`TERMS
`
`A Division. ofHarperCollinsPubltsbers
`
`dd
`. ‘
`HarperPerennial
`
`Ian R. Sinclair
`
`Series Editor, Eugene Ehrlich
`
`
`
`

`

`The HarperCollins Dictionary of Computer Terms
`Copyright © Ian R. Sinclair 1991
`All rights reserved. Printed in the United States of America. No part of this
`book may be used or reproduced in any manner whatsoever without
`written permission except in the case of brief quotations embodied in
`critical articles and reviews. For information address HarperCollins
`Publishers, 10 East 53rd Street, New York, NY. 10022.
`
`
`
`Library of Congress Cataloging-in-Publication Data
`
`Sinclair, Ian Robinson.
`
`[Collins dictionary of computing]
`Harper dictionary of computing / Ian R. Sinclair. — lst U.S. ed,
`lst HarperPerennial ed.
`p.
`cm.
`
`“Originally published 1986 in Great Britain by William Collins
`Sons 8: Co. under the title: Gem dictionary of computing; previously
`published with revisions 1988 in Great Britain by William Collins
`Sons 61 Co. under the title: Collins dictionary of computing”—T.p.
`verso.
`
`ISBN 0—06—271505—4——ISBN 0—06—461016—0 (pbk)
`1. Computers—Dictionaries. 2. Electronic data processing——
`Dictionaries. I. Title.
`
`QA76.15.S494 1991
`004’.03-——dc20
`
`90-55516
`
`919293949510987654321
`
`
`
`

`

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`PRINTOUT (Name,Address,Age)
`
`PROGRAMMER
`
`would call up a procedure called PRINTOUT, which would work
`with the values of variables Name, Address, and Age. This proce-
`dure would have to be defined before being used; however, the
`definition could use variables called A, B, and C, provided that
`these were of the same type as Name, Address, and Age, and in the
`same order.
`When a language permits use of procedures, the solution of prob-
`lems is greatly simplified. This is because each procedure can be
`looked on and worked on as a small program in its own right, inde-
`pendent of the other parts of the program. This makes possible
`MODULARIZATION of programs and also the maintenance of proce—
`dure LIBRARIES, which can be called on if a method requires a proce-
`dure that has been written before. See Fig. 57.
`processor the processing unit of a computer. See MICROPROCESSOR.
`program a set of instructions to a COMPUTER that will be carried out
`in order when a COMMAND such as RUN is given. See also INTER-
`PRETER, COMPILER, HIGH-LEVEL LANGUAGE, LOW-LEVEL LAN-
`GUAGE.
`
`program counter in ASSEMBLY LANGUAGE, the REGISTER of the
`microprocessor that stores the ADDRESS of the byte currently being
`read or written. This register is responsible for addressing memory
`and is the means by which the microprocessor can read and write
`data to and from the correct locations in the memory. A MACHINE
`CODE program is run by placing the address of its first byte into the
`program counter of the microprocessor.
`program crash see CRASH.
`programmable of or relating to anything capable of being pro-
`grammed. The microprocessor is a programmable device used in
`microcomputers. Some other chips, notably PORTS, SOUND CHIPS,
`and VIDEO INTERFACE chips, are also programmable but to a lesser
`extent.
`programmable key a FUNCTION KEY whose action can be changed
`by a command or program instruction. Also called SOFT KEY.
`programmer one who programs a computer. For MAINFRAME com-
`puters, the operator will have coded and typed the program, the
`programmer will have written the program, and the systems analyst
`will have produced the ALGORITHM. These distinctions are less clear
`
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