-
`
`CI'II'I:H I
`10,000
`Lri'I-iILe
`
`Microsoft"
`
`Cpmputer
`ictionary
`Fifth Edition ‘
`
`
`
`_
`- Fuiiy updated with the ieteet
`i'00ii00i0giee, terms, and 00r0nyme
`
`- Easy 00 read, expertiy iiiuetreted
`
`- Definitive 00verage 0f hardware,
`eefl‘were, the iniernet, and m0rei
`
`Apple 1012 (UPDATED)
`Apple V. Uniloc
`IPR2017-00220
`
`US. Patent No. 7,535,890
`
`0001
`
`Apple 1012 (UPDATED)
`Apple v. Uniloc
`IPR2017-00220
`U.S. Patent No. 7,535,890
`
`

`

`PUBLISHED BY
`Microsoft Press
`A Division of Microsoft Corporation
`One Microsoft Way
`Redmond, Washington 98052-6399
`
`Copyright © 2002 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 Computer Dictionary.--5th ed.
`p. cm.
`ISBN 0-7356-1495-4
`1. Computers--Dictionaries. 2. Microcomputers--Dictionaries.
`
`AQ76.5. M52267
`004'.03--dc21
`
`2002
`
`200219714
`
`Printed and bound in the United States of America.
`
`2 3 4 5 6 7 8 9 QWT
`
`7 6 5 4 3 2
`
`Distributed in Canada by H.B. Fenn and Company Ltd.
`
`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 informa-
`tion about international editions, contact your local Microsoft Corporation office or contact Microsoft
`Press International directly at fax (425) 936-7329. Visit our Web site at www.microsoft.com/mspress.
`Send comments to mspinput@microsoft.com.
`
`Active Desktop, Active Directory, ActiveMovie, ActiveStore, ActiveSync, ActiveX, Authenticode,
`BackOffice, BizTalk, ClearType, Direct3D, DirectAnimation, DirectDraw, DirectInput, DirectMusic,
`DirectPlay, DirectShow, DirectSound, DirectX, Entourage, FoxPro, FrontPage, Hotmail, IntelliEye,
`IntelliMouse, IntelliSense, JScript, MapPoint, Microsoft, Microsoft Press, Mobile Explorer, MS-DOS,
`MSN, Music Central, NetMeeting, Outlook, PhotoDraw, PowerPoint, SharePoint, UltimateTV, Visio,
`Visual Basic, Visual C++, Visual FoxPro, Visual InterDev, Visual J++, Visual SourceSafe, Visual Studio,
`Win32, Win32s, Windows, Windows Media, Windows NT, Xbox are either registered trademarks or
`trademarks of Microsoft Corporation in the United States and/or other countries. Other product and
`company names mentioned herein may be the trademarks of their respective owners.
`
`The example companies, organizations, products, domain names, e-mail addresses, logos, people, places,
`and events depicted herein are fictitious. No association with any real company, organization, product,
`domain name, e-mail address, logo, person, place, or event is intended or should be inferred.
`
`Acquisitions Editor: Alex Blanton
`Project Editor: Sandra Haynes
`
`Body Part No. X08-41929
`
`0002
`
`

`

`Contributors
`
`Peter Aiken
`
`Bart Arenson
`
`Janice Borzendowski
`
`Jerome Colburn
`
`Duane Hanson
`
`Andrew Himes
`
`Robert Howecton
`
`Annette B. Jackson
`
`Larry S. Jackson
`
`Thomas A. Jackson
`
`Chris Kinata
`
`Ilana Kingsley
`
`Robin Lombard
`
`Thomas A. Long
`
`William G. Madison
`
`Illustrators
`
`Travis Beaven
`
`David Holter
`
`Alton Lawson
`
`Thomas P. Magliery
`
`David Mason
`
`Terrence M. McLaren
`
`Wallace Parker
`
`Charles Petzold
`
`Phil Rose
`
`John Ross
`
`David Rygmyr
`
`Aimée Truchard
`
`Michael Vose
`
`Bruce Webster
`
`Judson D. Weeks
`
`Tom Winn
`
`JoAnne Woodcock
`
`Rob Nance
`
`Joel Panchot
`
`0003
`
`

`

`Contents
`
`Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
`Changes in the Fifth Edition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
`Order of Presentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
`Entries. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
`Future Printings and Editions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
`
`Dictionary of Computer Terms . . . . . . . . . . . . . . . 1
`
`Appendix A:
`Common Character Sets. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 587
`ANSI Character Set. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .587
`Apple Macintosh Extended Character Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .593
`IBM Extended Character Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .597
`EBCDIC Character Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .599
`Appendix B:
`Common File Extensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 605
`
`Appendix C:
`Instant Messaging Emoticons and Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 613
`
`Appendix D:
`Internet Domains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 623
`
`Appendix E:
`Numeric Equivalents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 631
`
`v
`
`0004
`
`

`

`D
`
`double-dereference
`
`
`
`downstream1downstream
`
`data. Double-density disks increased that capacity to 360
`KB. Double-density disks use modified frequency modu-
`lation encoding for storing data. See also floppy disk,
`microfloppy disk, modified frequency modulation
`encoding. Compare high-density disk.
`double-dereference vb. To dereference a pointer that is
`pointed to by another pointer; in other words, to access the
`information pointed to by a handle. See also dereference,
`handle (definition 1), pointer (definition 1).
`double leap year n. The mistaken idea that the year 2000
`would have two leap days—February 29 and February
`30—instead of one. In actuality, there was a potential leap
`year problem in 2000, but it was based on three rules for
`calculating leap years: (1) A year is a leap year if it is
`divisible by 4, but (2) not if it is divisible by 100, unless (3)
`it is also divisible by 400. Thus, 1900 was not a leap year,
`but 2000 is, although systems based on incorrect algo-
`rithms may not recognize it as a leap year and so may have
`difficulties functioning correctly after February 28, 2000.
`double posting n. In newsgroup discussions, the practice
`of replying to one’s own posts. Because it may be seen as
`the digital equivalent to talking to one’s self, double post-
`ing is considered an undesirable practice.
`double-precision adj. Of, pertaining to, or characteristic
`of a number stored in twice the amount (two words—typi-
`cally 8 bytes) of computer memory that is required for
`storing a less precise (single-precision) number. Double-
`precision numbers are commonly handled by a computer
`in floating-point form. See also floating-point number.
`Compare single-precision.
`double-sided disk n. A floppy disk that can hold data on
`both its top and bottom surfaces.
`double slash n. See //.
`double-strike n. On an impact printer, such as a daisy-
`wheel printer, the process of printing twice over a word, pro-
`ducing text that appears darker and heavier, or bolder, than it
`normally appears. On dot-matrix printers, double striking
`with a slight offset can be used to fill in the space between
`the dots, producing smoother and darker characters.
`double supertwist nematic display n. See supertwist
`display.
`double word n. A unit of data consisting of two contigu-
`ous words (connected bytes, not text) that are handled
`together by a computer’s microprocessor.
`
`doubly linked list n. A series of nodes (items represent-
`ing discrete segments of information) in which each node
`refers to both the next node and the preceding node.
`Because of these two-way references, a doubly linked list
`can be traversed both forward and backward, rather than in
`a forward direction only, as with a singly linked list.
`down adj. Not functioning, in reference to computers,
`printers, communications lines on networks, and other
`such hardware.
`downflow n. One of the four stages of the data warehous-
`ing process, during which stored information is delivered
`and archived. See also data warehouse2. Compare inflow,
`metaflow, upflow.
`downlink n. The transmission of data from a communica-
`tions satellite to an earth station.
`download vb. 1. In communications, to transfer a copy of
`a file from a remote computer to the requesting computer
`by means of a modem or network. 2. To send a block of
`data, such as a PostScript file, to a dependent device, such
`as a PostScript printer. Compare upload.
`downloadable font n. A set of characters stored on disk
`and sent (downloaded) to a printer’s memory when needed
`for printing a document. Downloadable fonts are most
`commonly used with laser printers and other page printers,
`although many dot-matrix printers can accept some of
`them. Also called: soft font.
`Downloadable Sounds n. A standard for synthesizing
`wave sounds from digital samples stored in software. The
`DLS level 1 and level 2 standards are published by the
`MIDI Manufacturers Association. Acronym: DLS.
`downsample n. To decrease the number of audio samples
`or pixels, by applying an operation such as averaging.
`Popular internet music formats, such as MP3, use down-
`sampling to reduce file size.
`downsizing n. In computing, the practice of moving from
`larger computer systems, such as mainframes and mini-
`computers, to smaller systems in an organization, gener-
`ally to save costs and to update to newer software. The
`smaller systems are usually client/server systems com-
`posed of a combination of PCs, workstations, and some
`legacy system such as a mainframe, connected in one or
`more local area networks or wide area networks. See also
`client/server architecture, legacy system.
`downstream1 n. The direction in which information,
`such as a news feed for a newsgroup or data from an http
`
`175
`
`0005
`
`

`

`E
`
`e-tail
`
`event-driven processing
`
`ratings for computer games and other interactive products
`such as Web sites, online games, and interactive chat.
`e-tail n. See e-commerce.
`e-text n. Short for electronic text. A book or other
`text-based work that is available on line in an electronic
`media format. An e-text can be read online or downloaded
`to a user’s computer for offline reading. See also e-zine.
`Ethernet n. 1. The IEEE 802.3 standard for contention
`networks. Ethernet uses a bus or star topology and relies
`on the form of access known as Carrier Sense Multiple
`Access with Collision Detection (CSMA/CD) to regulate
`communication line traffic. Network nodes are linked by
`coaxial cable, by fiberoptic cable, or by twisted-pair wir-
`ing. Data is transmitted in variable-length frames contain-
`ing delivery and control information and up to 1500 bytes
`of data. The Ethernet standard provides for baseband
`transmission at 10 megabits (10 million bits) per second
`and is available in various forms, including those known
`as Thin Ethernet, Thick Ethernet, 10Base2, 10Base5,
`10Base-F, and 10Base-T. The IEEE standard dubbed
`802.3z, or Gigabit Ethernet, operates at 10 times 100
`Mbps speed. See also ALOHAnet, baseband, bus network,
`coaxial cable, contention, CSMA/CD, Gigabit Ethernet,
`IEEE 802 standards, twisted-pair cable. 2. A widely used
`local area network system developed by Xerox in 1976,
`from which the IEEE 802.3 standard was developed.
`Ethernet/802.3 n. The IEEE standard for 10- or
`100-Mbps transmissions over an Ethernet network. Ether-
`net/802.3 defines both hardware and data packet construc-
`tion specifications. See also Ethernet.
`E-time n. See execution time.
`etiquette n. See netiquette.
`ETX n. See end-of-text.
`Eudora n. An e-mail client program originally developed
`as freeware for Macintosh computers by Steve Dorner at
`the University of Illinois, now maintained in both freeware
`and commercial versions for both Macintosh and Win-
`dows by Qualcomm, Inc.
`EULA n. See End-User License Agreement.
`Euphoria n. Acronym for End User Programming with
`Hierarchical Objects for Robust Interpreted Applications.
`An interpreted programming language intended for gen-
`eral application development and game programming on
`MS-DOS, Windows, and Linux platforms.
`
`European Computer Manufacturers Association
`n. See ECMA.
`European Laboratory for Particle Physics n. See CERN.
`EUV lithography n. Acronym for Extreme UltraViolet
`lithography. Manufacturing process allowing smaller cir-
`cuits to be etched onto chips than is possible with tradi-
`tional lithographic techniques. With this process, it is
`possible to economically produce chips that are much
`faster than those that are created using traditional pro-
`cesses. In EUV lithography, the image of a map of circuits
`to appear on a chip is bounced off a series of mirrors that
`condense the image. The condensed image is projected
`onto wafers containing layers of metal, silicon, and photo-
`sensitive material. Because EUV light has a short wave-
`length, extremely intricate circuit patterns can be created
`on the wafers.
`evaluation n. The determination, by a program, of the
`value of an expression or the action that a program state-
`ment specifies. Evaluation can take place at compile time
`or at run time.
`even parity n. See parity.
`event n. An action or occurrence, often generated by the
`user, to which a program might respond—for example,
`key presses, button clicks, or mouse movements. See also
`event-driven programming.
`event-driven adj. Of, pertaining to, or being software that
`accomplishes its purpose by responding to externally
`caused events, such as the user pressing a key or clicking a
`button on a mouse. For example, an event-driven data
`entry form will allow the user to click on and edit any field
`at any time rather than forcing the user to step through a
`fixed sequence of prompts.
`event-driven processing n. A program feature belong-
`ing to more advanced operating-system architectures such
`as the Apple Macintosh operating system, Windows, and
`UNIX. In times past, programs were required to interro-
`gate, and effectively anticipate, every device that was
`expected to interact with the program, such as the key-
`board, mouse, printer, disk drive, and serial port. Often,
`unless sophisticated programming techniques were used,
`one of two events happening at the same instant would be
`lost. Event processing solves this problem through the cre-
`ation and maintenance of an event queue. Most common
`events that occur are appended to the event queue for the
`program to process in turn; however, certain types of
`events can preempt others if they have a higher priority.
`
`198
`
`0006
`
`

`

`L
`
`L
`
`L1 cache n. A memory cache built into i486 and higher-
`level processors to help improve processing speed. The L1
`cache, typically containing 8 KB, can be read in a single
`clock cycle, so it is tried first. The i486 contains one L1
`cache; the Pentium contains two, one for code and one for
`data. Also called: level 1 cache, on-chip cache. See also
`cache, i486DX, Pentium. Compare L2 cache.
`L2 cache n. A memory cache consisting of static RAM
`on a motherboard that uses an i486 or higher-level proces-
`sor. The L2 cache, which typically contains 128 KB to 1
`MB, is faster than the system DRAM but slower than the
`L1 cache built into the CPU chip. Also called: level 2
`cache. See also cache, dynamic RAM, i486DX, static
`RAM. Compare L1 cache.
`L2TP n. See Layer Two Tunneling Protocol.
`L8R adv. Abbreviation for later, as in “See you later,” an
`expression often used in e-mail or Usenet groups as a clos-
`ing remark.
`label n. An identifier. A label can be a physical item, such
`as a stick-on tag used to identify disks and other computer
`equipment, or an electronic label added to floppy disks or
`hard disks. It can also be a word, symbol, or other group of
`characters used to identify a file, a storage medium, an
`element defined in a computer program, or a specific item
`in a document such as a spreadsheet or a chart. See also
`identifier.
`label edge router n. See MPLS.
`label prefix n. In a spreadsheet, a character at the begin-
`ning of a cell entry that identifies the entry to the program
`as a label.
`label switching n. See MPLS.
`label switch path n. See MPLS.
`label switch router n. See MPLS.
`LACP n. Acronym for Link Aggregation Control Proto-
`col. See link aggregation.
`lag n. The time difference between two events. In elec-
`tronics, a lag is a delay between a change in input and a
`change in output. On computer displays, a lag is a fading
`
`brightness left on the phosphor coating of the screen after
`an image changes. See also persistence.
`LAN n. Acronym for local area network. A group of com-
`puters and other devices dispersed over a relatively limited
`area and connected by a communications link that enables
`any device to interact with any other on the network.
`LANs commonly include PCs and shared resources such
`as laser printers and large hard disks. The devices on a
`LAN are known as nodes, and the nodes are connected by
`cables through which messages are transmitted. See also
`baseband network, broadband network, bus network, cli-
`ent/server architecture, collision detection, communica-
`tions protocol, contention, CSMA/CD, network, peer-to-
`peer architecture, ring network, star network. Compare
`WAN.
`landscape mode n. A horizontal print orientation in
`which text or images are printed “sideways”—that is, the
`width of the image on the page is greater than the height.
`Compare portrait mode.
`landscape monitor n. A monitor that is wider than it is
`high. Landscape monitors are usually about 33 percent
`wider than they are high—roughly the same proportion as
`a television screen. Compare full-page display, portrait
`monitor.
`LANE n. Acronym for LAN Emulation. See ATM (defini-
`tion 1), communications protocol, LAN.
`LANGID n. See language identifier.
`language n. See programming language.
`language-description language n. See metalanguage.
`language identifier n. A standard international numeric
`abbreviation for a country or geographical region. A lan-
`guage identifier is a 16-bit value that consists of a primary
`language identifier and a secondary language identifier.
`Acronym: LANGID. See also locale identifier.
`language processor n. A hardware device or a software
`program designed to accept instructions written in a par-
`ticular language and translate them into machine code. See
`also compiler (definition 2), interpreter.
`
`304
`
`0007
`
`

`

`Packet Internet Groper
`
`page banner
`
`source and destination addresses and control and timing
`information, that is needed for successful transmission.
`Packet Internet Groper n. See ping1 (definition 1).
`packet sniffer n. A hardware and/or software device that
`examines every packet sent across a network. To work, a
`packet sniffer must be installed in the same network block
`as the network it is intended to sniff. Designed as a prob-
`lem-solving tool to isolate problems degrading network
`performance, packet sniffers have become security risks
`on some networks because crackers can use them to cap-
`ture nonencrypted user IDs, passwords, credit card num-
`bers, e-mail addresses, and other confidential information.
`See also cracker, packet. Compare monitoring software.
`packet switching n. A message-delivery technique in
`which small units of information (packets) are relayed
`through stations in a computer network along the best
`route available between the source and the destination. A
`packet-switching network handles information in small
`units, breaking long messages into multiple packets before
`routing. Although each packet may travel along a different
`path, and the packets composing a message may arrive at
`different times or out of sequence, the receiving computer
`reassembles the original message correctly. Packet-
`switching networks are considered to be fast and efficient.
`To manage the tasks of routing traffic and assembling/dis-
`assembling packets, such a network requires some intelli-
`gence from the computers and software that control
`delivery. The Internet is an example of a packet-switching
`network. Standards for packet switching on networks are
`documented in the International Telecommunication
`Union (ITU) recommendation X.25. Compare circuit
`switching.
`Packet Switching Exchange n. An intermediary
`switching station in a packet-switching network.
`packet trailer n. The portion of a data packet that follows
`the body (data). The trailer typically contains information
`related to error checking and correction. See also packet.
`packing density n. The number of storage units per
`length or area of a storage device. Bits per inch is one
`measure of packing density.
`PackIT n. A file format used on the Apple Macintosh to
`represent collections of Mac files, possibly Huffman com-
`pressed. See also Huffman coding, Macintosh.
`PAD n. See packet assembler/disassembler.
`
`P
`
`pad character n. In data input and storage, an extra char-
`acter inserted as filler to use up surplus space in a predefined
`block of a specified length, such as a fixed-length field.
`padding n. In data storage, the addition of one or more
`bits, usually zeros, to a block of data to fill it, to force the
`actual data bits into a certain position, or to prevent the
`data from duplicating a bit pattern that has an established
`meaning, such as an embedded command.
`paddle n. An early type of input device often used with
`computer games especially for side-to-side or up-and-
`down movements of an on-screen object. A paddle is less
`sophisticated than a joystick because it permits the user,
`by turning a dial, to specify movement along only a single
`axis. The paddle got its name because its most popular use
`was to control the on-screen paddles in the simple early
`video games, such as Pong. See the illustration.
`
`F0Pgn01.epsPaddle.
`paddle switch n. Any switch that has a wide handle. The
`large on/off switch on many IBM personal computers is
`one type of paddle switch.
`page n. 1. In word processing, the text and display ele-
`ments to be printed on one side of a sheet of paper, subject
`to formatting specifications such as depth, margin size,
`and number of columns. 2. A fixed-size block of memory.
`When used in the context of a paging memory system, a
`page is a block of memory whose physical address can be
`changed via mapping hardware. See also EMS, memory
`management unit, virtual memory. 3. In computer graph-
`ics, a portion of display memory that contains one com-
`plete full-screen image; the internal representation of a
`screenful of information. 4. See Web page.
`page banner n. A section of a Web page containing a
`graphic element and text, such as the page title. Page ban-
`ners are usually displayed at the top of a Web page. Page
`banners can also be used to link to other Web sites for
`advertising purposes. Also called: banner.
`
`386
`
`0008
`
`

`

`pulse width modulation
`
`Python
`
`pulse width modulation n. See pulse duration modulation.
`punched card n. An outdated computer-input medium
`made of stiff paper that stores data bits in columns contain-
`ing patterns of punched holes. The method for creating the
`patterns used for different byte values is called Hollerith
`coding. See also Hollerith tabulating/recording machine.
`punched-card reader n. See card reader.
`pure procedure n. Any procedure that modifies only data
`that is dynamically allocated (usually on the stack). A pure
`procedure cannot modify either global data or its own
`code. This restriction allows a pure procedure to be called
`simultaneously by separate tasks. See also reentrant code.
`purge vb. To eliminate old or unneeded information sys-
`tematically; to clean up, as files.
`push1 n. A technology developed in relation to the World
`Wide Web, designed to provide end users with personalized
`Web access by having a site actively “push” requested infor-
`mation to the user’s desktop, either automatically or at spec-
`ified intervals. Push was developed as a means of relieving
`users from having to actively retrieve (“pull”) information
`from the Web. It is not, as yet, especially popular.
`push2 vb. 1. To add a new element to a stack, a data struc-
`ture generally used to temporarily hold pieces of data
`being transferred or the partial result of an arithmetic
`operation. See also stack. Compare pop. 2. In networks
`and the Internet, to send data or a program from a server to
`a client at the instigation of the server. See also push2.
`Compare pull.
`
`put vb. In programming, to write data, typically to a file;
`in particular, to write a very small unit of data, such as a
`character.
`PVC n. Acronym for permanent virtual circuit. A perma-
`nent logical connection between two nodes on a packet-
`switching network. The PVC appears as a dedicated line
`to the nodes, but the data can be transmitted on a common
`carrier. See also common carrier, node (definition 2 ),
`packet switching, virtual private network. Compare SVC.
`pwd n. Acronym for print working directory. The UNIX
`command for displaying the current directory.
`PWM n. Acronym for pulse width modulation. See pulse
`duration modulation.
`PXE boot n. Acronym for Preboot Execution Environ-
`ment boot. A BIOS-supported technology used to boot a
`PC remotely. To power on a PC and boot it from the net-
`work, PXE must be enabled in the BIOS, and the NIC in
`the PC must be PXE compliant. PXE boot is specified in
`the Intel Wired for Management (WfM) standard. Also
`called: network boot.
`pyramid diagram n. A diagram that is used to show foun-
`dation-based relationships.
`Python n. A portable, interpreted, object-oriented pro-
`gramming language developed and freely distributed by its
`developer. Python runs on many platforms, including
`UNIX, Windows, OS/2, and Macintosh, and is used for
`writing TCP/IP applications.
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`P
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`431
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`quarter-inch cartridge
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`quicksort
`
`Because each quantum bit—called a qubit—represents
`multiple values, a quantum computer can be in multiple
`states simultaneously and can thus work on numerous
`problems at the same time to offer far more computing
`power than is currently available. Quantum computing is
`under investigation by the United States Defense
`Advanced Research Projects Agency (DARPA) and other
`groups. Although atoms of hydrogen and carbon have
`been used to create the rudiments of a quantum computer,
`the technology is still in its infancy.
`quarter-inch cartridge n. See QIC (definition 1).
`Quartz n. The 2-D drawing engine that forms the imaging
`foundation of the Mac OS X Aqua interface. The Quartz
`graphics application programming interface (API) is based
`on Adobe’s Portable Document Format (PDF) standard.
`quartz crystal n. A precisely shaped and precisely sized
`piece of the mineral quartz, used for its piezoelectric prop-
`erties. When a voltage is applied to a quartz crystal, it
`vibrates at a frequency determined by its size and shape.
`Quartz crystals are commonly used to control the fre-
`quency of oscillator circuits such as the clocks in micro-
`computers. See also piezoelectric.
`quasi-language n. A derogatory term for any program-
`ming language that, because of deficiencies, is not suitable
`for any serious work.
`qubit n. Short for quantum bit. The bits (currently,
`atomic particles) that make up the theoretical machines
`known as quantum computers. Qubits are unlike bits in
`current computers in that they exist in more than one state
`at the same time. They can, therefore, represent both 0 and
`1 simultaneously. Qubits, like quantum computers, are
`based on the science of quantum mechanics.
`query1 n. A specific set of instructions for extracting par-
`ticular data.
`query2 vb. To extract data from a database and present it
`for use.
`query by example n. A simple-to-use query language
`implemented on several relational database management
`systems. Using query by example, the user specifies fields
`to be displayed, intertable linkages, and retrieval criteria
`directly onto forms displayed on the screen. These forms
`are a direct pictorial representation of the table and row
`structures that make up the database. Thus, the construc-
`tion of a query becomes a simple “checkoff” procedure
`from the viewpoint of the user. Acronym: QBE.
`
`query language n. A subset of the data manipulation lan-
`guage; specifically, that portion relating to the retrieval
`and display of data from a database. It is sometimes used
`loosely to refer to the entire data manipulation language.
`See also data manipulation language.
`question mark n. See ?.
`queue1 n. A multi-element data structure from which (by
`strict definition) elements can be removed only in the
`same order in which they were inserted; that is, it follows
`a first in, first out (FIFO) constraint. There are also several
`types of queues in which removal is based on factors other
`than order of insertion—for example, some priority value
`assigned to each element. See also deque, element (defini-
`tion 1). Compare stack.
`queue2 vb. To place (an item) in a queue.
`queued access method n. A programming technique
`that minimizes input/output delays by synchronizing the
`transfer of information between the program and the com-
`puter’s input and output devices. Acronym: QAM.
`queuing n. In networking, the process of buffering data in
`preparation for transmission. See also fair queuing; first
`in, first out; last in, first out; weighted fair queuing.
`QuickDraw n. On the Apple Macintosh, the built-in group
`of routines within the operating system that controls the
`display of graphics and text. Application programs call
`QuickDraw for on-screen displays. See also Toolbox.
`QuickDraw 3-D n. A version of the Macintosh Quick-
`Draw library that includes routines for doing 3-D graphics
`calculations. See also QuickDraw.
`Quicken n. Financial-management software from Intuit,
`Inc. The personal-finance version, introduced by Intuit in
`1984, includes tools for balancing and tracking bank
`accounts and investments, budgeting, paying bills, plan-
`ning and preparing tax returns, financial planning, and
`estate planning. A small-business version, Quicken Home
`& Business, adds tools for business-related matters, such
`as invoicing and accounts receivable and payable.
`quicksort n. An efficient sort algorithm, described by
`C.A.R. Hoare in 1962, in which the essential strategy is to
`“divide and conquer.” A quicksort begins by scanning the
`list to be sorted for a median value. This value, called the
`pivot, is then moved to its final position in the list. Next,
`all items in the list whose values are less than the pivot
`value are moved to one side of the list, and the items with
`values greater than the pivot value are moved to the other
`
`Q
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`433
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`0010
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