DICTIONARY
`of
`COMPUTER
`TERMS
`
`SEVENTH EDITION
`
`The Best Computer Dictionary in Print
`
`Nevv edition, completely revised
`
`Ext ensive Int ernet coverage
`
`More than 4,30 0 ter ms and a cronyms
`
`0001
`
`Google Inc.
`GOOG 1031
`IPR2016-00212
`
`

`
`Webster's NewWorld™
`
`Dictionary of Computer Terms, 7th Edition
`
`Copyright © 1999 by
`Simon & Schuster, Inc.
`
`All rights reserved
`including the right of reproduction
`in whole or in part in any form
`
`Macmillan General Reference
`A Simon & Schuster Macmillan Company
`1633 Broadway
`NewYork, NY 10019-6785
`
`Macmillan Publishing books may be purchased for business or
`sales promotional use. For information please write: Special
`Markets Department, Macmillan Publishing USA,
`1633 .Broadway, NewYork, NY 10019.
`
`A Webster's NewWorld™ Book
`
`MACMILLAN is a registered trademark of Macmillan, Inc.
`
`WEBSTER'S NEW"WORLD DICTIONAR.Y is a registered trade(cid:173)
`mark of Simon & Schuster, Inc.
`
`Library of Congress Catalog Card Number: 98-68180
`
`ISBN: 0-02-862884-5·
`
`ManufactUred in the United States of America
`
`1234567
`
`00 1 02 03 04
`
`0002
`
`

`
`(Q}
`
`DA See desk accessory.
`
`DAC Acronym for digital-to-analog converter. Synonymous
`with aualog-to-digital converter (AID converter).
`
`daemon A program, usually on a computer running Unix,
`char serves some obscure function (such as routing e-mail to its
`recipients) and usually has a very limited user interface. There's
`some debate about the origins of the word, but most say it
`derives from the devilish spirits of Greek mythology.
`
`daisy chain A method of connecting together several devices
`along a bus and managing the signals for each device. Devices
`that use a SCSI interface, such as a CD-ROM, hard disk, and
`scanner, can be daisy-chained to one SCSI port.
`
`daisy chaining
`In displays, the act of linking several monitors
`tOgether so they all show the same thing. Daisy chaining is con(cid:173)
`venient when large numbers of people must sec the output of a
`computer simultaneously, such as at a convention or trade show.
`See daisy chain.
`
`daisywheel printer An obsolete impact printer that simulates
`the typescript produced by a typewriter. The term daisywheel
`refers to the metal or plastic disk consisting of characters
`mounted on spokes connected to a hub, resembling a daisy. To
`produce a character, the printer spins the wheel until chat char(cid:173)
`acter is in front of a hammer that strikes rhe character against an
`inked ribbon, transferring the image to paper. Daisywheel print(cid:173)
`ers can print many typefaces, but changing fonts within a docu(cid:173)
`ment is tedious, because you must change the daisywheel
`manually. See impact printer.
`
`DARPA See Defense Advanced Research Project Ageucy.
`
`DASD See direct access storage device.
`OAT Acronym for Digital Audio Tape. A digital magnetic taP~
`format originally developed for CO-quality audio recording an
`now used for computer backup tapes. The latest OAT storage
`format, ODS, specifies storage capacities of up co 24 GB.
`
`database management system 137
`data Factual information (such as text, numbers, sounds, and
`images) in a form that can be processed by a computer.
`Although data is the plural of the Larin word dacum, the term
`"data" is commonly used to represent both singular and plural.
`In formal contexts (such as university computer science and
`engineering departments), the plural (data) and the singular
`(datum) are sometimes distinguished.
`
`database A collection of related information about a subject
`organized in a useful manner that provides a base or foundation
`for procedures, such as retrieving information, drawing conclu(cid:173)
`sions, and making decisions. Any collection of information that
`serves these purposes qualifies as a database, even if the informa(cid:173)
`tion isn't stored on a computer. In f.1ct, important predecessors
`of today's sophisticated business database systems were files kept
`on index cards and stored in file cabinets. Information usually is
`divided into data records, each with one or more data fields. See
`relational database.
`
`database design The choice and arrangement of data fields in
`a database so that fundamental errors (such as data redundancy
`and repeating fields) are avoided or minimized.
`
`database driver A program that enables a spreadsheet pro(cid:173)
`gram to exchange data with other database programs, such as
`dBASE.
`
`database management Tasks related to creating, maintaining,
`organizing, and retrieving information from a database. See data
`llumipulation.
`
`database management program An application program
`that provides the tools for data retrieval, modification, deletion,
`.llld insertion. Such programs also can create a database and pro(cid:173)
`duce meaningful output on a printer or on-screen. In personal
`computing, three kinds of database management programs exist:
`Oat-file, relational, and text-oriented. See baud.
`
`database management system (DBMS) A program
`that organizes data in a database, providing information storage,
`organization, and retrieval capacities, sometimes including
`Itnultaneous access to multiple databases through a shared field
`relational database management). See Jlat:file database manage(cid:173)
`:~ program and relational database 111a11agement system
`''VBMs).
`
`0003
`
`

`
`476 seek
`e Integrity (ensuring that transmitted or stored data is not
`altered by unauthorized persons in a way that is not
`detectable by authorized users).
`
`e Nonrepudiation (ensuring that qualified users are not
`denied access to services that they legitimately expect to
`receive, and that originators of messages cannot deny that
`they in fact sent a given message).
`
`seek
`In a disk drive, to locate a specific region of a disk and to
`position the read/write head so that the computer can retrieve
`data or program instructions.
`
`seek time
`In a secondary storage device, the time that it takes
`the read/write head to reach the correct location on the disk.
`See access time.
`
`segmented memory architecture A computer memory
`design in which the addresses of specific locations in the random
`access memory (RAM) are specified by means of segments (base
`addresses) and offsets (the number of data elements away from
`the base address). The use of segments and offsets enables com(cid:173)
`puter system designers to use more system memory than would
`be permitted by the width of the address bus.
`
`select To highlight part of a document so the program can
`identify the material on which you want to perform the next
`operation. In addition to selecting text, you can highlight or
`select an item from a list box or select a check box item to tog-
`gle it on or off.
`
`selection 1. A portion of a document's text or graphics that
`has been highlighted in reverse video for formatting or editing
`purposes. 2. In programming, a branch or conditional control
`structure. 3. In database management programs, the retrieval of
`records by using a query. See branch control structure.
`
`selection control structure
`In structured programming, a
`method ofhandling a program branch by using an IF-THEN(cid:173)
`ELSE structure. This is much more efficient than using a GOTO
`statement. Also called a conditional or branch control structure.
`
`self-extracting archive A compressed file that contains the
`software needed to decompress itself. Double-clicking a self(cid:173)
`extracting archive launches the decompression portion of the
`program and decompresses the files.
`
`sequence control structure 477
`
`semantic net
`In hypertext theory, a set of connections among
`the ideas in a document. To create a hypertext document, you
`first "chunk" the document-breaking the document into
`"chunks" or units of meaning. For example, a hypertext docu(cid:173)
`ment on California wines might break the subject down into
`the following categories: wineries, wine varietals, history of
`California wine, climate of wine-growing areas, and scientific
`research on wine growing. A separate document would cover
`each of these topics. Hyperlinks within the document exploit
`every possible connection with every other document in the
`series of linked documents, which is called a semantic net (this
`term is synonymous with web, spelled with a small w).
`
`semiconductor A material, such as silicon or germanium, that
`is less electrically conductive than excellent electrical conduc(cid:173)
`tors, such as copper, and insulating materials. Semiconductor
`wafers or chips of varying resistance can be assembled to create a
`variety of electronic devices. In personal computers, semicon(cid:173)
`ductor materials are used for microprocessors, memory, and
`other circuits. See integrated circuit.
`
`sendmail A Unix utility that sends e-mail over the Internet in
`accordance with the SMTP protocol. To create the message, you
`use an e-mail client such as Eudora or Netscape Messenger. Mail
`is received and stored by the programs conforming to the Post
`Office Protocol (POP).
`
`send statement
`In a SLIP or PPP dialer program's script lan(cid:173)
`guage, a statement that tells the program to send certain charac(cid:173)
`ters. Send statements follow expect statements, which tell the
`program to wait until the service provider's computer sends cer(cid:173)
`tain characters to your computer.
`
`sensor glove
`In virtual reality (VR) systems, an interface that
`is worn on a hand and enables the user to manipulate and move
`virtual objects in a virtual reality environment. See head-mounted
`display (HMD).
`
`sequence control structure A control structure that tells the
`computer to execute program statements in the order in which
`the statements were written. One of three fundamental control
`structures that govern the order in which program statements are
`executed, the sequence control structure is the default in all pro(cid:173)
`gramming languages.You can use loops and branch control
`structures to alter the sequence.
`
`0004