Encyclopedia of Computer Science and Technology

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DNS 157NONPNRNTNUNZOMPAPEPFPGPHPKPLPMPNPRPTPWPYQARERORURWSASBSCSDSESGSHSISJSKSLSMSNSOSRSTSUSVSYSZTCTDTFTGTHTJTKTMTNTOTPNorwayNepalNauruNeutral ZoneNiueNew Zealand (Aotearoa)OmanPanamaPeruFrench PolynesiaPapua New GuineaPhilippinesPakistanPolandSt. Pierre and MiquelonPitcairnPuerto RicoPortugalPalauParaguayQatarReunionRomaniaRussian FederationRwandaSaudi ArabiaSolomon IslandsSeychellesSudanSwedenSingaporeSt. HelenaSloveniaSvalbard and Jan Mayen IslandsSlovak RepublicSierra LeoneSan MarinoSenegalSomaliaSurinameSao Tome and PrincipeUSSR (former)El SalvadorSyriaSwazilandTurks and Caicos IslandsChadFrench Southern TerritoriesTogoThailandTajikistanTokelauTurkmenistanTunisiaTongaEast TimorTRTTTVTWTZUAUGUKUMUSUYUZVAVCVEVGVIVNVUWFWSYEYTYUZAZMZRZWTurkeyTrinidad and TobagoTuvaluTaiwanTanzaniaUkraineUgandaUnited KingdomUS Minor Outlying IslandsUnited StatesUruguayUzbekistanVatican City State (Holy See)Saint Vincent and the GrenadinesVenezuelaVirgin Islands (British)Virgin Islands (U.S.)Viet NamVanuatuWallis and Futuna IslandsSamoaYemenMayotteYugoslaviaSouth AfricaZambiaZaireZimbabweDomains and AddressesA complete Internet address generally consists of a wordrepresenting the name of the organization or company, possiblyfollowed by the name of a department or division.This is followed by the top-level domain. Here are someexamples:well.com The Well conferencing system, a business in theU.S.acm.org The Association for Computing Machinery, a nonprofitprofessional organizationstate.gov United States Department of Stateberkeley.edu University of California, Berkeleywww2.physics.ox.ac.uk Department of Physics, Oxford University,Oxfordshire, United Kingdom.To access a service at a given site, the host address is prefixedto indicate the server or service. Most commonly, thisis www for World Wide Web. Thus www.well.com indicatesthe Web server at the well.com host, while ftp.well.comwould indicate the ftp (file transfer protocol) server. (Insome cases, if there is no prefix, www will be assumed.)A complete Web address or URL (Uniform ResourceLocator) also includes a prefix for the protocol to be used(see World Wide Web). Most commonly this is http:// (forhypertext transfer protocol), though most Web browsers
158 documentation of program codewill treat this as the default and not require that it be typed.ftp:// can be used to access ftp servers via the Web. Finally,a URL must include the path to the directory that actuallycontains the HTML document or other resource, as wellas its filename. Thus a complete address for a hypotheticaluser’s home page might be:http://www.BigUniversity.edu/users/tomr/index.htmlInternal AddressingWhen a Web user types such an address, the Web browserconnects to a nearby name server. This program translatesthe name into an IP (Internet Protocol) address. Theaddress consists of four 8-bit numbers called tuples, separatedby periods. For example, the domain name www.well.com currently translates to 208.178.101.2. The first numberrepresents one of five classes of networks, with thefirst three classes (A-C) organized according to the numberand size of networks and D and E being reserved for oneto-many“broadcast” transmissions and experimentationrespectively.To obtain a domain name, a person or organizationcontacts one of several registration services accredited byICANN (the nonprofit Internet Corporation for assignedNames and Numbers). Each name must be unique. Considerablelegal disputation has occurred when someonenot connected with a company has registered a domaincontaining that company’s name. The tremendous growthof e-commerce has made distinctive or easy-to-rememberdomain names a scarce and valuable commodity. Foreseeingthis, some speculators bought up attractive domains inthe hope (sometimes realized) of selling them to corporationsat a huge profit. Anti–“domain squatting” laws werepassed in reaction. In other cases, disgruntled employees orconsumers have registered domains for Web sites critical ofmajor corporations such as airlines and telephone companies.In the courts, this pits the right of free speech againstthe right of a company to control the use of its name.Expanding the SystemThe expansion of the Internet has strained the capacity ofthe existing DNS. The shortage of “name space” is beingaddressed by the release of IP Version 6, which replaces the32-bit addresses with 128-bit ones. In addition, in November2000 ICANN announced the creation of seven new topleveldomains: .aero (air transport), .biz (business), .coop(cooperatives), .info (general-purpose), .museum (museums),.name (personal sites), and .pro (professionals suchas lawyers, accountants, and physicians). However, the situationis muddled by the existence of competing proposalsand the use of unofficial DNS systems that provide theirown domains (but require special software for access, sincethey are not recognized by regular DNS servers).Perhaps a more fundamental issue is the adopting ofa system designed by English speakers to a world thatincreasingly seeks international access and standards (seeinternationalization). The problem is how to meet localneeds without creating new barriers through incompatibleaddressing schemes. The proposal being implemented as ofthe mid-2000s is called Internationalizing Domain Namesin Applications (IDNA). This standard includes an algorithmby which address labels written using the many charactersets and diacritical marks in the world’s languages(as rendered in Unicode) can be translated to the standardASCII characters used by the existing DNS (see charactersand strings).Further ReadingAlbitz, Paul, and Cricket Liu. DNS and BIND, 4th ed. Sebastopol,Calif.: O’Reilly, 2001.ICANN (Internet Corporation for Assigned Names and Numbers).Available online. URL: http://www.icann.org/. AccessedAugust 14, 2007.“Internationalization of Domain Names: A History of Technology.”Internet Society. www.isoc.org/pubpolpillar/docs/i18n-dnschronology.pdf.Accessed July 10, 2007.InterNIC. Available online. URL: http://www.internic.net/. AccessedAugust 14, 2007.InterNIC Registry WhoIs [domain look-up]. Available online.URL: http://www.internic.net/whois.html. Accessed August14, 2007.documentation of program codeComputer system documentation can be divided into twomain categories based upon the intended audience. Manualsand training materials for users focus on explaininghow to use the program’s features to meet the user’s needs(see documentation, user). This entry, however, focuseson the creation of documentation for programmers and othersinvolved in software development and maintenance (seealso technical writing).Software documentation can consist of commentsdescribing the operation of a line or section of code. Earlyprogramming with its reliance on punched cards had onlyminimal facilities for incorporating comments. (Some of theproponents of COBOL thought that the language’s Englishlikesyntax would make additional documentation unnecessary.Like the similar claim that trained programmerswould no longer be needed, the reality proved otherwise.)After the switch from punchcard input to the use ofkeyboards, adding comments became easier. For example, acomment in C looks like this:printf(“Hello, world\n”);/* Display the traditional message */while C++ uses comments in this form:cout
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Encyclopedia ofComputer scienceand
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C on t e n t sAcknowledgmentsivintr
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I n t r od u c t ion to t h eR e v
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Introduction to the Revised Edition
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AdaAdaStarting in the 1960s, the U.
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Advanced Micro Devices (AMD)Image P
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Algolgrammar of the data-descriptio
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ALUdown into component parts or bui
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10 Amdahl, Gene MyronShanahan, Fran
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12 analog and digitalhistory, bring
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14 Andreessen, MarcCompleted in 193
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16 animation, computerAndreessen tr
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18 APLAPL (a programming language)T
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20 application program interfacerat
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22 application softwareURL: http://
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24 arrayIn languages such as C that
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26 artificial intelligenceby tradit
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28 artificial lifewriters such as V
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30 Atanasoff, John VincentAtanasoff
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32 authoring systemsway”—the se
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34 awkthose found in C. There are a
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36 backup and archive systemsthe ec
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38 Backus-Naur formBackus-Naur form
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40 basic input/output systemdecisio
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42 Bell Laboratoriesand the early a
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44 Bezos, Jeffrey P.use if it is to
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46 bioinformaticsand a hierarchy of
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48 biometricsvariety of biometric s
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50 bitmapped imagesuch tasks as gra
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52 blogs and bloggingThe shift oper
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54 boot sequenceoperators (called B
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oadbandTechnically, broadband refer
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Brooks, Rodney 59such as Flickr and
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ulletin board systems 61bugs and de
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66 CTotal = Total + 1;Total += 1;To
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68 C++While attracted to the advant
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70 calculatorthe location of the ca
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72 cascading style sheetsMojave Des
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74 CD-ROM and DVD-ROM“rapid proto
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76 censorship and the InternetIn 20
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78 central processing unitcentral p
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80 CGIIn a newly emerging sector th
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82 characters and stringsAs compute
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84 chess and computersOne of the be
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86 chipsetattached to the silicon s
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90 clock speedSinclair, Joseph T.,
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92 codecMurcah, Mike, Anne Prince,
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94 COMcommon object request broker
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96 compilersuch as a keyword (reser
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98 computer-aided design and manufa
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100 computer crime and securitycomp
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102 computer forensicsa device proc
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104 computer graphicsthe same time,
Page 119 and 120: 106 computer industryso on). By cre
Page 121 and 122: 108 computer industrypackages serve
Page 123 and 124: 110 computer virus• What is the b
Page 125 and 126: 112 computer visionsense on the par
Page 127 and 128: 114 conferencing systemsFeldman, Mi
Page 129 and 130: 116 cookiesunlike most traditional
Page 131 and 132: 118 CORBA“activation” or “val
Page 133 and 134: 120 CraigslistMano, M. Morris, and
Page 135 and 136: 122 CRMtasks can be assigned to dif
Page 137 and 138: 124 cyberneticsMany issues regardin
Page 139 and 140: 126 cyberstalking and harassmentThe
Page 141 and 142: DdataToday the term data is associa
Page 143 and 144: 130 database administrationsignal m
Page 145 and 146: 132 database management systemMicro
Page 147 and 148: 134 data compressionlocal network,
Page 149 and 150: 136 data securityparticular purpose
Page 151 and 152: 138 data typeswhile a list has one
Page 153 and 154: 140 Dell, Inc.User Interface—The
Page 155 and 156: 142 design patternsdesign patternsD
Page 157 and 158: 144 device driverOne Laptop per Chi
Page 159 and 160: 146 digital cashcould be worked bac
Page 161 and 162: 148 digital dashboardThe ownership
Page 163 and 164: 150 Dijkstra, Edsger W.discs. A big
Page 165 and 166: 152 disaster planning and recoveryT
Page 167 and 168: 154 distributed computingAnother wa
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Page 173 and 174: 160 document modelSociety for Techn
Page 175 and 176: 162 DRMresearchers. For example, Al
Page 177 and 178: 164 DVRMPEG file) that is fully com
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Page 181 and 182: 168 e-commerceRemington Rand. Worki
Page 183 and 184: 170 education and computersApplicat
Page 185 and 186: 172 e-governmentlenges face educati
Page 187 and 188: 174 Electronic Artsteaching softwar
Page 189 and 190: 176 e-maillanguages. However this c
Page 191 and 192: 178 employment in the computer fiel
Page 193 and 194: 180 encapsulationconsist of a combi
Page 195 and 196: 182 Engelbart, DouglasEngelbart, Do
Page 197 and 198: 184 entrepreneurs in computinganaly
Page 199 and 200: 186 error correctionSalvendy, Gavri
Page 201 and 202: 188 expert systemsAnatomy of an Exp
Page 203 and 204: 190 Feigenbaum, Edwardhttp://hissa.
Page 205 and 206: 192 file serverdata integrity. Vers
Page 207 and 208: 194 film industry and computingImpl
Page 209 and 210: 196 firewallcontrolled by a state t
Page 211 and 212: 198 flash and smart mobs(or even pr
Page 213 and 214: 200 flowchartused to hold data. The
Page 215 and 216: 202 FORTRANearly days of microcompu
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Page 219 and 220: 206 Gates, William, IIIGame console
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208 Geographical Information System
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210 Google• downward wage pressur
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212 government funding of computer
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214 graphics formatsof objects so t
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216 grid computingoff. By 2000, vir
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218 Grove, Andrew S.Cavalancia, Nic
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220 handwriting recognitionand othe
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222 hard disk• remote surgery, wh
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224 health, personalTo search a has
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226 history of computingFurther Rea
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228 history of computingThe most st
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230 home officeFacing vigorous comp
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232 HTML, DHTML, and XHTMLFurther R
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234 hypertext and hypermediaImpleme
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236 IBM PCFurther ReadingBashe, Cha
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238 identity theftfrom meetings to
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240 information retrievalinvasion o
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242 information warfareShannon foun
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244 installation of softwareinstall
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246 internationalization and locali
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248 Internettransmission of a messa
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250 Internet censorshipDunaev, Serg
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252 interpreterconsidered to be ISP
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JJavaJava is a computer language si
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256 JavaScriptIn 2006 Sun Microsyst
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258 Jobs, Steven Paulan enthusiasti
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260 journalism and the computer ind
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262 Joy, Billwho will be unable to
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264 kernelcould send a message to t
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266 knowledge representationattende
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268 Kurzweil, RayFurther ReadingFre
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LLAN See local area network.languag
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272 laptop computerapplications for
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274 Lessig, Lawrencepleadings and o
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276 library, programadditional copi
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278 linguistics and computingIn his
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280 LISPA Linux system running Open
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282 list processinga rich variety o
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284 Logoa checksum, and two special
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286 LuaNext CharValHere Char$ is a
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288 macroMacDailyNews. Available on
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290 mainframeMaes has participated
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292 map information and navigation
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294 mashupsbefore you buy” softwa
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296 Mauchly, John WilliamMoving fro
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298 measurement units used in compu
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300 medical applications of compute
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302 memory managementTom’s Hardwa
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304 microprocessorMicroprocessor de
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306 Microsoft .NETbrowser had broug
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308 Microsoft WindowsIntroduced in
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310 middlewareBott, Ed, Carl Sieche
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312 minicomputer“How Military Rob
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314 Mitnick, Kevin D.———. “
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316 molecular computingdevice could
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318 Moore, Gordon E.only one gun, w
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320 Motorola CorporationMotorola Co
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322 multimediaa maximum of 640 kB o
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324 multitasking“local” memory
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326 music and video distribution, o
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328 music and video players, digita
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330 natural language processingplac
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332 Net Neutrality• Do not post b
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334 networkGoogle Groups, is the be
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336 neural networkwebmd.com/stroke/
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338 numeric dataselect customer whe
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340 object-oriented programmingPARC
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342 Omidyar, Pierreprovided for typ
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344 online advertisingnew structure
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346 online gamblingand agencies suc
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348 online investingThe close and g
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350 online servicesand drugs. The s
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352 open-source movementopen-source
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354 operators and expressionsOperat
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356 optical computingA more general
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PPage, Larry(1973- )AmericanEntrepr
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360 parallel porthis work. Papert l
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362 PascalLevine, John R., Tony Mas
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364 PDATheodoridis, Sergios, and Ko
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366 personal computerConway, Damian
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368 personal information managercom
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370 phishing and spoofing“Phishin
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372 PHPeach of the three RGB colors
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374 Plug and PlayImpact of the Lang
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376 pointers and indirectionA point
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378 popular culture and computingHo
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380 presentation softwareDeclineBy
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382 printersarray of magnetically c
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384 procedures and functionsagencie
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386 programming as a professioncalc
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388 programming languagesprogrammer
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390 PrologGiven the scope and pace
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392 punched cards and paper tapepun
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Qquality assurance, softwareModern
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396 queueIn an empty queue, the hea
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RRAID (redundant array of inexpensi
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400 recursionand with the potential
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402 regular expressioncompetitive a
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404 reverse engineeringA similar ap
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406 RFIDParts of an RFID system. De
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408 risks of computingHafner, Katie
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410 roboticsMac. The MIT computer s
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412 RPGHenderson, Harry. Modern Rob
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414 Rubya file, as with many script
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416 satellite Internet serviceFurth
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418 science fiction and computingre
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420 scientific computing applicatio
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422 search engineuseful tools for m
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424 semantic WebSearch Engine Watch
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426 Shannon, Claude E.Service-orien
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428 shellPC-Write as a full-feature
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430 Simonyi, Charlestests for the p
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432 singularity, technologicalToget
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434 smart buildings and homesThis m
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436 smartphonestore a hundred or mo
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438 SOAPPogue, David. iPhone: The M
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440 social networkingThere continue
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442 software agentLife could be stu
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444 software piracy and counterfeit
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446 sorting and searching• Discma
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448 sound file formatsapproach, and
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450 Spafford, Eugene H.and computer
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452 spreadsheetSpeech recognition b
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454 SQLFurther Reading“Antispywar
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456 stackstackOften a temporary sto
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458 Stoll, CliffordCharles Babbage
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460 structured programmingsuited fo
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462 supply chain managementApplicat
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464 system administratorsystem admi
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Ttablet PCAs the name suggests, a t
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468 TclHaylor, Phil. Computer Stora
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470 technical supportIPv6 Informati
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472 technology policyDuring the 198
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474 telepresence• elimination of
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476 text editortyping commands into
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478 touchscreencode. This would mea
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480 trends and emerging technologie
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482 Turkle, SherryFurther ReadingHe
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Uubiquitous computingTraditionally
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486 USB% who | awk ' { print $1 }'H
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488 user groupsGarofoli, Joe. “Us
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VvariableVirtually all computer pro
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492 videoconferencingconsequence wa
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494 virtualizationused as an expres
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496 VoIPtank crews and even individ
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498 von Neumann, JohnJohn von Neuma
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WWales, Jimmy(1966- )AmericanIntern
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502 Web 2.0 and beyond“Web 2.0”
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504 webcamabout a 75 percent market
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506 Web page design• fluency in t
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508 Web servicesWhen a user types i
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510 Wiener, Norbertcomplexity . . .
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512 wikis and WikipediaWiki softwar
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514 Wirth, NiklausMobile Wireless N
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516 word processingto promote netwo
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518 World Wide WebBy the beginning
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XXMLSeveral markup languages have b
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YY2K problemSherlock Holmes once re
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524 YouTube• excessive time spent
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526 Zuse, Konradneeded would make t
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528 Appendix IRed Herring: The Busi
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530 Appendix IIing company (CTR) in
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532 Appendix II• Users of the new
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534 Appendix II••ibm developed
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536 Appendix II• Bill Gates and P
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538 Appendix II• A consortium cal
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540 Appendix II• Apple released o
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Appendix IIISome Significant Awards
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544 Appendix III1993 Juris Harmanis
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546 Appendix III1972 Paul E. Dirkse
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548 Appendix IIIJohn W. BackusRober
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550 Appendix IIIsity of Manchester
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552 Appendix IIIthereby enhancing A
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554 Appendix IVInternational Webmas
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556 IndexAnalytical Engine 35-36, 3
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558 Indexdata communications over13
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560 Indexgraphics in 106, 194haptic
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562 IndexDertouzos, Michael L. 141D
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564 IndexFFacebook 16, 440-441, 487
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566 IndexIDNA (Internationalizing D
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568 Indexin open-source movement352
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570 IndexMinard, Joseph 239mind 92-
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572 IndexOnStar 71ontologies and da
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574 Indexin object-orientedprogramm
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576 Indexsequential calculator 5ser
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578 Indexterminals in 475-476user i
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580 Indexdatabases in 132developmen
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