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`Terms
`
`Additional Terms
`Available On Line
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`Apple 1014
`U.S. Pat. 9,189,437
`
`

`
`PUBLISHED BY
`Microsoft Press
`A Division of Microsoft Corporation
`One Microsoft Way
`Redmond, Washington 98052-6399
`
`Copyright ' 1997 by Microsoft Corporation
`
`All rights reserved. No part of the contents of this book may be reproduced or transmitted
`in any form or by any means without the written permission of the publisher.
`
`Library of Congress Cataloging-in-Publication Data
`Microsoft Press Computer Dictionary. -- 3rd ed.
`p. cm.
`ISBN 1-57231-446-X
`1. Computers--Dictionaries. 2. Microcomputers--Dictionaries.
`I. Microsoft Press.
`QA76.15.M54 1997
`004’.03--dc21 (cid:9)
`
`97-15489
`CIP
`
`Printed and bound in the United States of America.
`
`3456789 QMQM 21098
`
`Distributed to the book trade in Canada by Macmillan of Canada, a division of Canada Publishing
`Corporation.
`
`A CIP catalogue record for this book is available from the British Library.
`
`Microsoft Press books are available through booksellers and distributors worldwide. For further
`information about international editions, contact your local Microsoft Corporation office. Or contact
`Microsoft Press International directly at fax (425) 936-7329.
`
`Macintosh, Power Macintosh, QuickTime, and TrueType are registered trademarks of Apple Computer,
`Inc. Intel is a registered trademark of Intel Corporation. Directlnput, DirectX, Microsoft, Microsoft
`Press, MS-DOS, Visual Basic, Visual C++, Win32, Win32s, Windows, Windows NT, and XENIX are
`registered trademarks and ActiveMovie, ActiveX, and Visual J++ are trademarks of Microsoft
`Corporation. Java is a trademark of Sun Microsystems, Inc. Other product and company names
`mentioned herein may be the trademarks of their respective owners.
`Acquisitions Editor: Kim Fryer
`Project Editor: Maureen Williams Zimmerman, Anne Taussig
`Technical Editors: Dail Magee Jr., Gary Nelson, Jean Ross, Jim Fuchs, John Conrow, Kurt Meyer,
`Robert Lyon, Roslyn Lutsch
`
`

`
`the change with each sample as needed, thus
`increasing the effective bit resolution of the data.
`Acronym: ADPCM (AD-P-C-M). See also pulse
`code modulation. Compare adaptive differential
`pulse code modulation.
`adaptive differential pulse code modulation
`\ -daptiv dif-r-enshl puls kOd moj--lashn,
`mo-dy-1ªshn\ n. A digital audio compression
`algorithm that stores a sample as the difference
`between a linear combination of previous samples
`and the actual sample, rather than the measure-
`ment itself. The linear combination formula is
`modified every few samples to minimize the
`dynamic range of the output signal, resulting in
`efficient storage. See also pulse code modulation.
`Compare adaptive delta pulse code modulation.
`adaptive system \ -dap tiv sistm\ n. A system
`that is capable of altering its behavior based on
`certain features of its experience or environment.
`See also expert system.
`ADB \KD-B\ n. See Apple Desktop Bus.
`ADC \KD-C\ n. See analog-to-digital converter.
`A-D converter \A-D’ kn-vrtr\ n. See analog-
`to-digital converter.
`adder \adm\ n. 1. A CPU (central processing
`unit) component that adds two numbers sent to it
`by processing instructions. See also central pro-
`cessing unit. 2. A circuit that sums the amplitudes
`of two input signals. See also full adder, half
`adder.
`add-in \adin\ n. See add-on.
`addition record \-dishn rekrd\ n. 1. A file
`that describes new record entries (such as a new
`customer, employee, or product) in a database so
`that they can later be scrutinized and posted. 2. A
`record in a change file specifying a new entry. See
`also change file.
`add-on \adon\ n. 1. A hardware device, such as
`an expansion board or chip, that can be added to
`a computer to expand its capabilities. Also called
`add-in. See also open architecture (definition 2).
`2. A supplemental program that can extend the
`capabilities of an application program. See also
`utility program.
`address’ \adres, -dres\ n. 1. A number specify -
`ing a location in memory where data is stored. See
`also absolute address, address space, physical
`address, virtual address. 2. A name or token spec-
`
`ifying a particular site on the Internet or other net-
`work. 3. A code used to specify an e-mail
`destination.
`address \adres, -dres\ vb. To reference a par-
`ticular storage location.
`addressable cursor \-dres-bl kursr\ n. A
`cursor programmed so that it can be moved to any
`location on the screen, as by means of the key-
`board or a mouse.
`address book \adres b(Tk, -dres\ n. 1. In an
`e-mail program, a reference section listing e-mail
`addresses and individuals’ names. 2. As a Web
`page, an informal e-mail or URL phone book. See
`the illustration.
`
`address bus \adres bus, -dres\ n. A hardware
`path usually consisting of 20 to 64 separate lines
`used to carry the signals specifying a memory
`location. See also bus.
`address decoder \adres dº-k ,5dr, -dres\ n.
`An electronic device that converts a numeric
`address so as to select a memory location on one
`or more RAM chips.
`addressing \-dresºng, adres-ºng\ n. The pro-
`cess of assigning or referring to an address. In
`programming, the address is typically a value
`specifying a memory location. See also address’.
`address mapping table \adres map ’ºng tªbl, -
`dres\ n. A table used by routers or Domain Name
`System (DNS) servers to resolve Internet Protocol
`UP) addresses from a text entry such as a name.
`
`U
`
`I!,
`
`

`
`amplitude (cid:9)
`
`analog-to-digital converter
`
`Amiga.
`
`amplitude \ ampl-td \ n. A measure of the
`strength of a signal, such as sound or voltage,
`determined by the distance from the baseline to
`the peak of the waveform. See also waveform.
`amplitude modulation \ampl-td moj--lª -
`shun, mod-y-lashn\ n. A method of encoding
`information in a transmission, such as radio, using
`a carrier wave of constant frequency but of varying
`amplitude. See the illustration. Acronym: AM (AM).
`AMPS \KM-P-S\
`n. Acronym for Advanced
`Mobile Phone Service. One of the original cellular
`phone services, relying on frequency-division
`multiplexing.
`
`Encoding signal
`
`/
`
`AMPS/NAMPS \ amps N amps, A-M-P-SNA-M-P -
`S\ n. See AMPS, NAMPS.
`AMT \KM-T\ n. See address mapping table.
`.an \dotA-N\ n. On the Internet, the major geo-
`graphic domain specifying that an address is
`located in the Netherlands Antilles.
`analog \ an-log \ adj. Pertaining to or being a
`device or signal having the property of continu-
`ously varying in strength or quantity, such as volt-
`age or audio. Compare digital (definition 2).
`analog channel \an-log chanol\ n. A communi-
`cations channel, such as a voice-grade telephone
`line, carrying signals that vary continuously and
`can assume any value within a specified range.
`analog computer \an-log km-py(cid:246)tr\
`n. A
`computer that measures data varying continuously
`in value, such as speed or temperature.
`analog data \an-log dªt, dat\ n. Data that is
`represented by continuous variations in some
`physical property, such as voltage, frequency, or
`pressure. Compare digital data transmission.
`analog display \ an-log dis-plª’ \ n. A video dis-
`play capable of depicting a continuous range of
`colors or shades rather than discrete values. Com-
`pare digital display.
`analog line \ an-log lin \ n. A communications
`line, such as a standard telephone line, that carries
`continuously varying signals.
`analog signal generator \an-log sig-nl jenr-
`ª-tr\ n. A device that generates continuously vari-
`able signals and is sometimes used to activate an
`actuator in a disk drive. See also actuator.
`analog-to-digital converter
`\ an-log-t-difi-tl
`kn-vrtor\ n. A device that converts a continu-
`ously varying (analog) signal, such as sound or volt-
`age, from a monitoring instrument to binary code
`for use by a computer. See the illustration. Acro-
`nym: ADC (A’D-C). Also called A-D converter. See
`also modem. Compare digital-to-analog converter.
`
`/
`
`Carrier wave
`
`Amplitude modulation. (cid:9)
`
`Analog-to-digital converter.
`
`

`
`information (such as a memory address, a data
`type, or an actual value). See also binding time,
`dynamic binding, static binding.
`binding time \ bin dºng tim" \ n. The point in a
`program’s use at which binding of information
`occurs, usually in reference to program elements
`being bound to their storage locations and values.
`The most common binding times are during com-
`pilation (compile-time binding), during linking
`(link-time binding), and during program execution
`(run-time binding). See also bind, compile-time
`binding, link-time binding, run-time binding.
`BinHex 1 \binheks\ n. 1. A code for converting
`binary data files into ASCII text so they can be
`transmitted via e-mail to another computer or in a
`newsgroup post. This method can be used when
`standard ASCII characters are needed for transmis-
`sion, as they are on the Internet. BinHex is used
`most frequently by Mac users, See also MIME.
`2. An Apple Macintosh program for converting
`binary data files into ASCII text and vice versa
`using the BinHex code. Compare uudecode’,
`uuencode 1 .
`BinHex 2 \bin’heks\ vb. To convert a binary file
`into printable 7-bit ASCII text or to convert the
`resulting ASCII text file back to binary format
`using the BinHex program. Compare uudecode 2 ,
`uuencode 2 .
`binomial distribution \ bi-n(cid:246)"mº-1 dis-tr-bydO
`shn\ n. In statistics, a list or a function that
`describes the probabilities of the possible values
`of a random variable chosen by means of a Ber-
`noulli sampling process. A Bernoulli process has
`three characteristics: each trial has only two possi-
`ble outcomes(cid:151)success or failure; each trial is
`independent of all other trials; and the probability
`of success for each trial is constant. A binomial dis-
`tribution can be used to calculate the probability
`of getting a specified number of successes in a
`Bernoulli process. For example, the binomial dis-
`tribution can be used to calculate the probability
`of getting a 7 three times in 20 rolls of a pair of
`dice. Also called Bernoulli distribution.
`bionics \bi-on"iks"\ n. The study of living organ-
`isms, their characteristics, and the ways they func-
`tion, with a view toward creating hardware that
`can simulate or duplicate the activities of a biologi-
`cal system. See also cybernetics.
`
`BIOS \bi"Os, B"I-O-S’\ n. Acronym for basic
`input/output system. On PC-compatible comput-
`ers, the set of essential software routines that test
`hardware at startup, start the operating system,
`and support the transfer of data among hardware
`devices. The BIOS is stored in read-only memory
`(ROM) so that it can be executed when the com-
`puter is turned on. Although critical to perfor-
`mance, the BIOS is usually invisible to computer
`users. See also AMI BIOS, CMOS setup, Phoenix
`BIOS, ROM BIOS. Compare Toolbox.
`bipolar \bi"p(cid:246)lr\
`adj. 1. Having two opposite
`states, such as positive and negative. 2. In infor-
`mation transfer and processing, pertaining to or
`characteristic of a signal in which opposite volt-
`age polarities represent on and off, true and
`false, or some other pair of values. See also non-
`return to zero. Compare unipolar. 3. In electron-
`ics, pertaining to or characteristic of a transistor
`having two types of charge carriers. See also tran-
`sistor.
`BIS \B"I-S’\ n. See business information system.
`bistable \bi"stª’bl\ adj. Of, pertaining to, or char -
`acteristic of a system or device that has two possi-
`ble states, such as on and off. See also flip-flop.
`bistable circuit \bi-stª"bl sr’kt\ n. Any circuit
`that has only two stable states. The transition
`between them must be initiated from outside the
`circuit. A bistable circuit is capable of storing 1 bit
`of information.
`bistable multivibrator \bi-stª"bl mul-ti-vi"brª-
`tar, mul-tº-vi"brª-tr\ n. See flip-flop.
`BISYNC \bisºnk\ n. Short for binary synchro-
`nous communications protocol. A communica-
`tions standard developed by IBM. BISYNC
`transmissions are encoded in either ASCII or
`EBCDIC. Messages can be of any length and are
`sent in units called frames, optionally preceded by
`a message header. BISYNC uses synchronous
`transmission, in which message elements are sep-
`arated by a specific time interval, so each frame is
`preceded and followed by special characters that
`enable the sending and receiving machines to syn-
`chronize their clocks. STX and ETX are control
`characters that mark the beginning and end of the
`message text; BCC is a set of characters used to
`verify the accuracy of transmission. See the illus-
`tration on the next page. Also called BSC.
`
`

`
`bm
`
`superimposed on another image. Action or objects
`are filmed against a blue screen. The desired back-
`ground is filmed separately, and the shot contain-
`ing the action or objects is superimposed onto the
`background. The result is one image where the
`blue screen disappears.
`.bm \dotB-M\ n. On the Internet, the major geo-
`graphic domain specifying that an address is
`located in Bermuda.
`.bmp \dot-BM-P\ n. The file extension that iden-
`tifies raster graphics stored in bit map file format.
`See also bit map.
`.bn \dotB-N\ n. On the Internet, the major geo-
`graphic domain specifying that an address is
`located in Brunei Darussalam.
`BNC connector \B-N-C k-nektr\ n. A connec-
`tor for coaxial cables that locks when one
`connector is inserted into another and rotated 90
`degrees. BNC connectors are often used with
`closed-circuit television. See the illustration. See
`also coaxial cable.
`
`BNC connector. Male (left) and female
`(right) BNC connectors.
`
`.bo \dotB-O\ n. On the Internet, the major geo-
`graphic domain specifying that an address is
`located in Bolivia.
`board \b(cid:246)rd\
`n. An electronic module consisting
`of chips and other electronic components
`mounted on a flat, rigid substrate on which con-
`ductive paths are laid between the components. A
`personal computer contains a main board, called
`the motherboard, which usually has the micropro-
`cessor on it and slots into which other, smaller
`boards, called cards or adapters, can be plugged
`to expand the functionality of the main system,
`such as to connect to monitors, disk drives, or a
`network. See also adapter, card (definition 1),
`motherboard.
`board computer \bOrd km-py(cid:246)tr\
`single-board.
`
`n. See
`
`board level \b(cid:246)rd levl\
`n. A level of focus in
`troubleshooting and repair that involves tracking
`down a problem in a computer to a circuit board
`and replacing the board. This is in contrast to the
`component level, which involves repairing the
`board itself. In many cases board-level repairs are
`made in order to quickly restore the device to
`working condition; the boards replaced are then
`repaired and tested for use in later board-level
`repairs. See also circuit board.
`body \bodº\ n. In e-mail and Internet news-
`groups, the content of a message. The body of a
`message follows the header, which contains infor -
`mation about the sender, origin, and destination of
`the message. See also header (definition I).
`body face \bodº fªs\ n. A typeface suitable for
`the main text in a document rather than for head-
`ings and titles. Because of their readability, fonts
`having serifs, such as Times and Palatino, are good
`body faces, although sans serif faces can also be
`used as body text. See also sans serif, serif. Com-
`pare display face.
`BOF \BO-F, bof\ n. 1. Acronym for birds of a
`feather. Meetings of special interest groups at
`trade shows, conferences, and conventions. BOF
`sessions provide an opportunity for people work-
`ing on the same technology at different companies
`or research institutions to meet and exchange their
`experiences. 2. See beginning-of-file.
`boilerplate \ boi lr-plªt \ n. Recyclable text; a
`piece of writing or code, such as an organization’s
`mission statement or the graphics code that prints
`a software company’s logo, which can be used
`over and over in many different documents. The
`size of boilerplate text can range from a paragraph
`or two to many pages. It is, essentially, generic
`composition that can be written once, saved on
`disk, and merged, either verbatim or with slight
`modification, into whatever documents or pro-
`grams later require it.
`boldface \b(cid:246)ldfªs\
`n. A type style that makes the
`text to which it is applied appear darker and
`heavier than the surrounding text. Some applica-
`tions allow the user to apply a "Bold" command to
`selected text; other programs require that special
`codes be embedded in the text before and after
`words that are to be printed in boldface. This sen-
`tence appears in boldface.
`
`5W
`
`

`
`bug-
`
`bubble memory
`\buVl memr-º\ n. Memory
`formed by a series of persistent magnetic "hubbies"
`in a thin film substrate. In contrast to ROM, infor-
`mation can be written to bubble memory. In contrast
`to RAM, data written to bubble memory remains
`there until it is changed, even when the computer
`is turned off. For this reason, bubble memory has
`had some application in environments in which a
`computer system must be able to recover with min-
`imal data loss in the event of a power failure. The
`use of and demand for bubble memory has all but
`disappeared because of the introduction of flash
`memory, which is less expensive and easier to pro-
`duce. See also flash memory, nonvolatile memory.
`bubble sort
`\ hub 1 s(cid:246)rt \ n. A sorting algorithm
`that starts at the end of a list with n elements and
`moves all the way through, testing the value of each
`adjacent pair of items and swapping them if they
`aren’t in the right order. The entire process is then
`repeated for the remaining n - 1 items in the list,
`and so on, until the list is completely sorted, with
`the largest value at the end of the list. A bubble sort
`is so named because the "lightest" item in a list (the
`smallest) will figuratively "bubble up" to the top of
`the list first; then the next-lightest item bubbles up
`to its position, and so on. See the illustration. Also
`called exchange sort. See also algorithm, sort. Com-
`pare insertion sort, merge sort, quicksort.
`
`List to be sorted
`3
`Compared last (::::4
`
`Compared second
`
`Compared third
`
`Compared first
`
`5 .
`
`1
`
`List after first (cid:9)
`pass (cid:9)
`
`List after second
`pass
`
`1 (cid:9)
`
`3 (cid:9)
`4 (cid:9)
`2 (cid:9)
`5 (cid:9)
`Bubble sort.
`
`1
`2
`
`3
`4
`5
`
`bubble storage \bubl stªrj\ n. See bubble
`memory.
`bucket \bukt\ n. A region of memory that is
`addressable as an entity and can be used as a
`receptacle to hold data. See also bit bucket.
`buffer’ \bufr\ n. A region of memory reserved
`for use as an intermediate repository in which data
`is temporarily held while waiting to be transferred
`between two locations, as between an applica-
`tion’s data area and an input/output device. A
`device or its adapter may in turn use a buffer to
`store data awaiting transfer to the computer or
`processing by the device.
`buffer \bufr\ vb. To use a region of memory to
`hold data that is waiting to be transferred, espe-
`cially to or from input/output (I/O) devices such
`as disk drives and serial ports.
`buffer pool \bufr p(cid:246)bl\ n. A group of memory
`or storage-device locations that are allocated for
`temporary storage, especially during transfer oper-
`ations.
`buffer storage \bufr stOrj\ n. 1. The use of a
`special area in memory to hold data temporarily
`for processing until a program or operating system
`is ready to deal with it. 2. An area of storage that
`is used to hold data to be passed between devices
`that are not synchronized or have different bit
`transfer rates.
`bug \bug\ n. 1. An error in coding or logic that
`causes a program to malfunction or to produce
`incorrect results. Minor bugs, such as a cursor
`that does not behave as expected, can be incon-
`venient or frustrating, but do not damage infor-
`mation. More severe hugs can require the user to
`restart the program or the computer, losing what-
`ever previous work had not been saved. Worse
`yet are bugs that damage saved data without
`alerting the user. All such errors must be found
`and corrected by the process known as debug-
`ging. Because of the potential risk to important
`data, commercial application programs are tested
`and debugged as completely as possible before
`release. After the program becomes available,
`further minor bugs are corrected in the next
`update. A more severe bug can sometimes be
`fixed with a piece of software called a patch,
`which circumvents the problem or in some other
`way alleviates its effects. See also beta test,
`
`IVI
`a
`
`

`
`censorware : (cid:9)
`
`..certitkation1
`
`usually delete highly controversial and obscene
`content or content that is on a different topic from
`that followed by the newsgroup. Online services
`have identifiable owners, who often take some
`share of responsibility for what reaches their users’
`computer screens. In some countries, censorship
`of certain political or cultural Web sites is a matter
`of national policy.
`censorware \ sensr-w(cid:226)r \
`n. Software that
`imposes restrictions on what Internet sites, news-
`groups, or files may he accessed by the user.
`center \sentr\ vb. To align characters around a
`point located in the middle of a line, page, or
`other defined area; in effect, to place text an
`equal distance from each margin or border. See
`also align (definition 1).
`centi- \senti-, sent-\ prefix 1. One hundred.
`2. One hundredth, as in centimeter(cid:151)one
`hun-
`dredth of a meter.
`centralized processing \ sen trn-lizd pros es-eng\
`n. The location of computer processing facilities
`and operations in a single (centralized) place.
`Compare decentralized processing, distributed
`processing.
`central office \sentrl of is\ n. In communica-
`tions, the switching center where interconnections
`between customers’ communications lines are
`made.
`central processing unit \sentrl proses-ºng yd-
`nit\ n. The computational and control unit of a
`computer. The central processing unit is the
`device that interprets and executes instructions.
`Mainframes and early minicomputers contained
`circuit boards full of integrated circuits that imple-
`mented the central processing unit. Single-chip
`central processing units, called microprocessors,
`made possible personal computers and worksta-
`tions. Examples of single-chip central processing
`units are the Motorola 68000, 68020, and 68030
`chips and the Intel 8080, 8086, 80286, 80386, and
`i486 chips. The central processing unit(cid:151)or micro-
`processor, in the case of a microcomputer(cid:151)has
`the ability to fetch, decode, and execute instruc-
`tions and to transfer information to and from other
`resources over the computer’s main data-transfer
`path, the bus. By definition, the central processing
`unit is the chip that functions as the "brain" of a
`computer. In some instances, however, the term
`
`encompasses both the processor and the com-
`puter’s memory or, even more broadly, the main
`computer console (as opposed to peripheral
`equipment). Acronym: CPU (CP-U). See also
`microprocessor.
`Centronics parallel interface \ sen-tron iks p(cid:226)r -
`lel intr-fªs\ n. A de facto standard for parallel
`data exchange paths between computers and
`peripherals, originally developed by the printer
`manufacturer Centronics, Inc. The Centronics par-
`allel interface provides eight parallel data lines
`plus additional lines for control and status infor-
`mation. See also parallel interface.
`CERN \srn, CE-R-N\ n. Acronym for Conseil
`EuropØen pour la Recherche NuclØaire (the Euro-
`pean Laboratory for Particle Physics). CERN, a
`physics research center located in Geneva, Swit-
`zerland, is where the original development of the
`World Wide Web took place by Tim Berners-Lee
`in 1989 as a method to facilitate communication
`among members of the scientific community. See
`also NCSA (definition 1).
`CERN server \srn srvr, CE-R-N\ n. One of
`the first Hypertext Transfer Protocol (HTTP) serv -
`ers, developed at CERN by Tim Berners-Lee. The
`CERN server is still in wide use and is free of
`charge. See also CERN, HTTP server (definition 1).
`CERT \srt, CE-R-T\ n. Acronym for Computer
`Emergency Response Team. An organization that
`provides a round-the-clock security consultation
`service for Internet users and provides advisories
`whenever new virus programs and other com-
`puter security threats are discovered.
`certification
`n. 1. The act of
`awarding a document to demonstrate a computer
`professional’s competence in a particular field.
`Some hardware and software suppliers, such as
`Microsoft and Novell, offer certification in the use
`of their products; other organizations, such as the
`Institute for Certification of Computer Profession-
`als (ICCP) and the Computing Technology Indus-
`try Association (CompTIA), offer more general
`certification. 2. The act of awarding a document to
`demonstrate that a hardware or software product
`meets some specification, such as being able to
`work with a certain other hardware or software
`product. 3. The issuance of a notice that a user or
`site is trusted for the purpose of security and
`
`U.
`$141
`
`U
`
`

`
`churn rate \churn rªt\ n. The rate of customer
`subscription turnover. In beeper, cell phone, and
`online businesses it is common for customers to
`drop their monthly subscriptions, creating a churn
`rate as high as 2 or 3 percent per month. High
`churn rates are costly to companies because
`attracting new subscribers through advertising and
`promotion is expensive.
`.ci \dotC-V\ n. On the Internet, the major geo-
`graphic domain specifying that an address is
`located in the Ivory Coast.
`CIDR \CI-D-R\ n. See classless interdomain rout-
`ing.
`CIFS \CI-F-S\ n. See Common Internet File System.
`CIM \CI-M\ n. 1. Acronym for computer-inte-
`grated manufacturing. The use of computers,
`communication lines, and specialized software to
`automate both the managerial functions and the
`operational activities involved in the manufactur -
`ing process. A common database is used in all
`aspects of the process, from design through
`assembly, accounting, and resource management.
`Advanced CIM systems integrate computer-aided
`design and engineering (CAD/CAE), material
`requirements planning (MRP), and robotic assem-
`bly control to provide "paperless" management of
`the entire manufacturing process. 2. Acronym for
`computer-input microfilm. A process in which
`information stored on microfilm is scanned and
`the data (both text and graphics) converted into
`codes that can be used and manipulated by a com-
`puter. Computer-input microfilm is similar to pro-
`cesses such as optical character recognition, in
`which images on paper are scanned and con-
`verted to text or graphics. Compare COM (defini-
`tion 4).
`.cincinnati.oh.us
`\ dot-sin-s-naC º-dot-O-I-F dot-
`U-S\ n. On the Internet, the major geographic
`domain specifying that an address is located in
`Cincinnati, Ohio, United States.
`cipher \siir\ n. 1. A code. 2. An encoded char -
`acter. 3. A zero.
`circuit \srkt\ n. 1. Any path that can carry elec-
`trical current. 2. A combination of electrical com-
`ponents interconnected to perform a particular
`task. At one level, a computer consists of a single
`circuit; at another, it consists of hundreds of inter -
`connected circuits.
`
`circuit analyzer \srkt an--lFzr\
`n. Any
`device for measuring one or more characteristics
`of an electrical circuit. Voltage, current, and resis-
`tance are the characteristics most commonly mea-
`sured. Oscilloscopes are circuit analyzers.
`circuit board \srkt b(cid:246)rd\
`n. A flat piece of
`insulating material, such as epoxy or phenolic
`resin, on which electrical components are
`mounted and interconnected to form a circuit.
`Most modern circuit boards use patterns of cop-
`per foil to interconnect the components. The foil
`layers may be on one or both sides of the board
`and, in more advanced designs, in several layers
`within the board. A printed circuit board is one in
`which the pattern of copper foil is laid down by a
`printing process such as photolithography. See
`the illustration. See also board, printed circuit
`board.
`
`Circuit board.
`
`circuit breaker \srkt brªkr\ n. A switch that
`opens and cuts off the flow of current when the
`current exceeds a certain level. Circuit breakers
`are placed at critical points in circuits to protect
`against damage that could result from excessive
`current flow, which is typically caused by compo-
`nent failure. Circuit breakers are often used in
`place of fuses because they need only to be reset
`rather than replaced. Compare surge protector.
`circuit card \srkt k(cid:228)rd\ n. See circuit board.
`Circuit Data Services \srkt dªt (cid:9)
`srvi-ss,
`dat\ n. A GTE service that uses circuit switching
`technology to provide fast data transfer using a
`laptop computer and cellular telephone. Acronym:
`CDS (CD-S). See also circuit switching.
`
`U..!
`94
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`
`[ommunications Act of 1934.
`
`both privately owned and public-access network
`computers. See also asynchronous transmission,
`CCITT, channel (definition 2), communications
`protocol, IEEE, ISDN, ISO/OSI model, LAN,
`modem, network, synchronous transmission.
`Compare data transmission, telecommunications,
`teleprocess.
`Communications Act of 1934 \k-myd-n-kª -
`shnz akt v nintºn-thr-tº-f(cid:246)r\
`n. See FCC.
`communications channel \ k-my-n-kª shnz
`chan1\ n. See channel (definition 2).
`communications controller
`\ k-myd-n-ka -
`shnz kn-trªlr\ n. A device used as an interme-
`diary in transferring communications to and from
`the host computer to which it is connected. By
`relieving the host computer of the actual tasks of
`sending, receiving, deciphering, and checking
`transmissions for errors, a communications con-
`troller helps to make efficient use of the host com-
`puter’s processing time(cid:151)time that might be better
`used for noncommunications tasks. A communica-
`tions controller can be either a programmable
`machine in its own right or a nonprogrammable
`device designed to follow certain communications
`protocols. See also front-end processor (defini-
`tion 2).
`communications link
`\ k-my-no-ka shonz
`1ºnk \ n. The connection between computers that
`enables data transfer.
`communications network \ k-my6-n-kªsh3nz
`netwrk\ n. See network.
`communications parameter
`\ k-myd(cid:246)-n-kª --
`shnz par-am-tr\ n. Any of several settings
`required in order to enable computers to commu-
`nicate. In asynchronous communications, for
`example, modem speed, number of data bits and
`stop bits, and type of parity are parameters that
`must be set correctly to establish communication
`between two modems.
`communications port
`\ k-myO-n-kª shnz
`port \ n. See COM (definition 1).
`communications program \ k-my(cid:246)-n-kashnz
`program\ n. A software program that enables a
`computer to connect with another computer and
`to exchange information. For initiating communi-
`cations, communications programs perform such
`tasks as maintaining communications parameters,
`storing and dialing phone numbers automatically,
`
`recording and executing logon procedures, and
`repeatedly dialing busy lines. Once a connection
`is made, communications programs can also be
`instructed to save incoming messages on disk or to
`find and transmit disk files. During communica-
`tion, these types of programs perform the major,
`and usually invisible, tasks of encoding data, coor -
`dinating transmissions to and from the distant
`computer, and checking incoming data for trans-
`mission errors.
`communications protocol
`\ k-my3b-n-kashnz
`prot-kol\ n. A set of rules or standards designed
`to enable computers to connect with one another
`and to exchange information with as little error as
`possible. The protocol generally accepted for stan-
`dardizing overall computer communications is a
`seven-layer set of hardware and software guide-
`lines known as the OSI (Open Systems Intercon-
`nection) model. A somewhat different standard,
`widely used before the OSI model was developed,
`is IBM’s SNA (Systems Network Architecture). The
`word protocol is often used, sometimes confus-
`ingly, in reference to a multitude of standards
`affecting different aspects of communication, such
`as file transfer (for example, XMODEM and ZMO-
`DEM), handshaking (for example, XON/XOFF),
`and network transmissions (for example, CSMA/
`CD). See also ISO/OSI model, SNA.
`communications satellite
`\ k-my(cid:246)-n-kashnz
`sat-lit\ n. A satellite stationed in geosynchro-
`nous orbit that acts as a microwave relay station,
`receiving signals sent from a ground-based station
`(earth station), amplifying them, and retransmit-
`ting them on a different frequency to another
`ground-based station. Initially used for telephone
`an