`
`Dictionary of
`Computer and
`Internet Terms
`
`
`
`TenthEdition
`
`Douglas A. Downing, Ph.D.
`School of Business and Economics
`Seattle Pacific University
`
`Michael A. Covington, Ph.D.
`Artificial Intelligence Center
`The University of Georgia
`
`Melody Mauldin Covington
`Covington Innovations
`Athens, Georgia
`
`Catherine Anne Covington
`Covington Innovations
`Athens, Georgia
`
`With the assistance of
`Sharon Covington
`
`BARRON'S
`
`1
`
`APPLE-1023
`
`APPLE-1023
`
`1
`
`

`

`ABOUT THE AUTHORS
`
`Douglas Downing teaches economics and quantitative methods at the School of
`Business and Economicsat Seattle Pacific University. He is the author of several
`books in both Barron’s Easy Way and Business Reviewseries. Heis also the author
`of Java Programming the Easy Way and Dictionary ofMathematics Terms, published
`by Barron’s Educational Series, Inc. He holds the Ph.D. degree in economics from
`Yale University.
`Michael Covington is Associate Director of the Artificial Intelligence Institute at
`the University of Georgia. He is the author of several books and over 250 magazine
`articles. He holds the Ph.D. degree in linguistics from Yale University.
`Melody Mauldin Covington is a graphic designer living in Athens, Georgia. She
`is the author of Dictionary of Desktop Publishing (published by Barron’s).
`Catherine Anne Covington is a student at
`the Lamar Dodd School of Art
`(University of Georgia).
`Sharon Covington is a student at Emory University.
`
`© Copyright 2009, 2006, 2003, 2000, 1998, 1996, 1995, 1992, 1989,
`and 1986 by Barron’s EducationalSeries,Inc.
`
`All rights reserved.
`No part of this book maybe reproduced ordistributed in
`any form or by any means without the written permission
`of the copyright owner.
`
`All inquiries should be addressed to:
`Barron’s EducationalSeries, Inc.
`250 Wireless Boulevard
`Hauppauge, NY 11788
`www.barronseduc.com
`
`ISBN-13: 978-0-7641-4105-8
`ISBN-10: 0-7641-4105-8
`
`Library of Congress Catalog Card No. 2008044365
`
`Library of Congress Cataloging-in-Publication Data
`Downing, Douglas.
`Dictionary of computer and Internet terms / Douglas A. Downing,
`Michael A. Covington, Melody Mauldin Covington. — 10th ed.
`p. cm.
`ISBN 978-0-7641-4105-8
`1. Computers—Dictionaries. 2. Internet—Dictionaries. I. Covington,
`Michael A., 1957- II. Covington, Melody Mauldin. III. Title.
`
`QA76.15.D667 2009
`004.03—dc22
`
`PRINTED IN CHINA
`987654321
`
`2008044365
`
`2
`
`

`

`248
`ignorelist
`the command in an if statement, butin C, doing so is legal (and alwa
`comesout true if the value assigned is nonzero).
`ignorelist a list of users you have blockedin a chatorinstant
`program. When anotheruser is on yourignore list, your so
`ignore messages from them. Synonyms: BLACKLIST; KILLFILE.
`IIOP (Internet Inter-ORB Protocol) a protocol that extends TCP/IP
`adding CORBA defined messages for objects to connect to each other
`over the network. See CORBA; PROTOCOL.
`,
`
`Messaging
`ftware wil|
`
`%
`
`IIRC online abbreviation for “if I remembercorrectly.”
`IIS (Internet Information Services) the component of Microsoft Windows
`(professional andservereditions only) that enables the computerto work
`as a web, FTP, and e-mail server.
`
`i.LINK see FIREWIRE.
`
`illegal operation an operation that a program is not permitted to perform,
`such as writing on a read-only disk or using memory allocated to some
`other program. Illegal operations are almost invariably the result of
`errors in programming.
`
`IM Instant Message or Messenger; see AIM; LIVE MESSENGER.
`
`iMaca line of Apple Macintosh computers with a distinctive streamlined
`design introduced in 1998. The current iMac computeris built entirely
`within its flat-screen monitor. See also APPLE; MACINTOSH.
`
`image
`1. a picture, represented in a computer’s memory. See GRAPHICS.
`2. a copy, on a disk, of the contents of a computer’s memory. A BOOT
`DISK may contain an imageinthis sense,i.e., a large block of data that
`can be copied directly into memory.
`
`image map a webpagegraphic to which multiple links have been assigned.
`It is possible to click on different parts of the picture and activate differ-
`ent links. For example, you might create a map of your community that
`appears on the web page;if the user clicks on the part of the maprepre-
`senting one neighborhood,then the browserwill jumpto a link provid-
`ing information about that neighborhood. This givesthe links a visual
`meaning that would notbe there inalist of text-only links. Image maps
`can be created with some web-creation software programs, or they can
`be defined directly by hand-coding the proper HTML.
`
`image processing the use of a computer to modify pictures (usually bitmap
`images). Applications of image processing include computer vision,
`enhancementof photographs, and creation of works ofart. Many image
`processingfunctionsare built into PAINT PROGRAMSasFILTERS(definition
`
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`249
`
`incremental compiler
`
`|). For examples, see ADD NOISE; BLEND; BLUR; BRIGHTNESS; COLOR/GRAY
`MAP; EDGE DETECT; EQUALIZE; HISTOGRAM; MOTION BLUR; PIXELATE,PIX-
`ELIZE; REMOVE SPOTS; SHARPEN; UNSHARP MASKING.See also COLOR; COM-
`PUTER; CONVOLUTION; DEBLURRING} RETOUCHING; VISION.
`
`jmagesetter a high-quality output device. Imagesetters can deliver up to
`2400 DPI(dots per inch) instead of the 300 to 1200 DPIof ordinary laser
`printers.
`
`IMAP(Internet Mail Access Protocol) a protocol for viewing e-mail on a
`personal computer while leavingit in place on the host system. Contrast
`poP, which delivers the mail anddeletes it from the server. See PROTOCOL.
`
`IMGtag used in HTMLto indicate an image file. For example, see HTML.
`
`IMHOonline abbreviation for “in my humble opinion.”
`
`IMOonline abbreviation for “in my opinion.”
`
`impact printer a printer that prints on paper by impacting a cloth ribbon
`coated with ink, thus transferring ink to the paper. Dot-matrix printers
`are the most commontype of impactprinter. Today, impact printers are
`used mainly for business forms that involve carbon paper or carbonless
`copy paper. See DOT-MATRIX PRINTER; LINE PRINTER; PICKUP ROLLER.
`
`impedance a measureof howeasily an alternating current can pass through
`an electrical circuit. The impedanceofa resistor is the sameasits resis-
`tance. Capacitors and inductors also affect impedance, depending on the
`frequency of the current. The impedanceofa capacitor decreases as the
`frequency increases; the impedanceof an inductor increases asthe fre-
`quency increases. The characteristic impedance ofcoaxial cable results
`from the interaction of its inductance and capacitance.It is not a resis-
`tance and cannot be measured with an ohmmeter. See COAXIAL CABLE.
`
`import to load a file from a format other than the application program’s
`native format. Many wordprocessing and graphics programs have the
`ability to import text and graphics from several different file formats.
`Because importing is a type of file conversion, formatting and image
`detail may be lost in the process. See CONVERSION PROGRAM.
`in the loop (jargon) involved in decision-makingorcontrol, like an auto-
`matic control system that uses feedback. See Loop (definition 2).
`
`incremental backup a backup operation that only copies files that have
`changedsince the last backup. See BACKUP COPY.
`
`incremental compiler a compiler that compiles the lines of a program as
`they are typed into the computer, rather than compiling the whole pro-
`gram at once. The purpose is to keep the programmer from having to
`wait a long time for the complete program to be compiled whenitis fin-
`ished. See COMPILER.
`
`4
`
`

`

`217
`
`Fe
`
`graphics
`
`(linear) or have the blend radiate from a central point(radial). See also
`FOUNTAINFILL; UNIFORMFILL.
`
`
`
`FIGURE 120. Gradientfill too! (from Adobe PhotoShop)
`
`grammarcheckera part of a word processing program thatflags sentences
`that violate rules of grammar. For example, in Microsoft Word, if you
`type “They is happy,” the word “is” will be marked with a wavy green
`underline to indicate that it is not grammatical. However, grammar
`checkers cannot alwaysberelied on to identify proper usage for your
`particular document.
`See also SPELL CHECKER.
`
`grandfather tape a tape that is two generations older than the currentdata;
`for example, a backup tape from two daysagoif backupsare donedaily.
`See also HARD DISK MANAGEMENT.
`
`graph
`1. a graphical display of information, designed to makeit easier for the
`reader to interpret and understand numerical data. See BAR GRAPH andPIE
`CHARTfor examples.
`2.
`in mathematics, a set of points connected together in a specific way.
`See TOPOLOGY.
`
`graphicaluser interface (GUI) a way of communicating with the computer
`by manipulating icons (pictures) and windows with a mouse. Before
`GUIs became widespread, it was common for computers to operate in a
`mode whereonly text (no graphics) could be displayed on the screen.
`Xerox developed a machine with a graphical user interface in the
`1970s, but the first widely used GUI machine was the Apple Macintosh
`in 1984. The release of Microsoft Windows 3.0 in 1990 led to wide-
`spread use of a graphical user interface on IBM PC-compatible comput-
`ers. For examples, see MACINTOSH; WINDOWS.
`graphics the use of computer output devices, such as screens, printers, and
`plotters,
`to produce pictures. The applications of computer graphics
`include publishing, education, entertainment, and the visualization of
`computed data(e.g., graphs of mathematical functions).
`There are two basic waysto tell a computer how to drawapicture. In
`vector graphics, the computeris told to put a real or imaginary pen ina
`particular position and then draw a line a certain distance in a certain
`direction (or draw a line to another specific point). The alternative is
`
`5
`
`5
`
`

`

`graphics card
`
`218
`
`raster graphics or bitmap graphics, in which the screen or plotting area
`is divided into a rectangular array of points (called pixels, from “picture
`cells”), and the computer is told what color each point should be.
`Computerscreensandprintersare raster devices, but somegraphicssoft-
`ware uses vector-style instructions internally so that all lines will appear
`as sharp as possible on the device actually used to display them.
`The amountoffine detail that a particular graphics device can show
`is called the resolution. The resolution of a printer is usually given in
`dots per inch; the resolution of a screenis given asthesize of the whole
`image. A goodlaser printer can print 1200 dots (pixels) per inch, so that
`an 8 x 10-inch picture is a 9600 x 12,000array ofpixels and containsfar
`more detail than the screen can display.
`
`fle Edt Yew Loos Mask Map Image Wed Hep
`Dicolea} Go)» |arfesf =e]as)of fe)el
`36) fests [O's freona)
`
`f
`
`[7
`
`FIGURE 121. Graphical userinterface (Windows)
`
`graphics card a video card that can display graphics as wellas text. All
`modern video cards are graphics cards. See SVGA; VGA.
`graphics tablet an alternative to a mouse. A graphics tablet consists of a
`pressure-sensitive pad on which you draw with a special pen called a
`STYLUS. This is much more natural
`than attempting to draw with a
`mouse. See DRAW PROGRAM; PAINT PROGRAM.
`
`grayed displayed in gray type and not available for selection. If a menu
`option appears in light gray rather than black type, it cannot be chosen
`(see Figure 78 on page 140). Menuselections are grayed wheneverit is
`impossible to do the thing they call for (e.g., “Save” may be grayedif
`there is no data to be saved). See DIMMED.
`graylist a spam filtering method in which message delivery is delayed for
`senders not on the WHITELIST or BLACKLIST. The messageis deliveredif
`it is re-sent (in the hope that spammers won't re-send and legitimate
`senders will).
`
`6
`
`