计算机专业英语影印版(Computing-Essentials-2008)课后答案大全——第九单元C

ComputingEssentials2008Chapter9:CommunicationsandNetworksKeyTermsPage1of6KeyTermsKeyTermDefinition3Gcellularnetwork(249)AcomputernetworkthatallowsuserstodownloaddatafromtheInternetat400to700Kbpsusingcellphonetechnology.analogsignal(247)Continuouselectronicwaves.asymmetricdigitalsubscriberline(ADSL)(248)ThemostwidelyusedtypesofDSL.backbone(258)Acommonconnectingcableonwhichallcommunicationstravelalong.(seealsobus)bandwidth(249)Ameasurementofthewidthorcapacityofthecommunicationchannel.basestation(254)Anetwork’scentrallylocatedreceiverthatinterpretsincomingradiofrequenciesandroutescommunicationstotheappropriatedevices.(seealsowirelessreceiver)bitspersecond(bps)(247)HowtransferspeedismeasuredBluetooth(245)Ashort-rangewirelesscommunicationstandardthatusesmicrowavestotransmitdataovershortdistancesbroadband(250)Thebandwidthusedforhigh-capacitytransmissions.broadcastradio(245)Usesradiosignalstosendandreceivesignalsfromwirelessdevices.bus(258)Acommonconnectingcableonwhichallcommunicationstravelalong.(seealsobackbone)busnetwork(258)Eachdeviceinthenetworkhandlesitsowncommunicationscontrol.cablemodem(249)Useexistingtelevisioncablestoprovidehigh-speedconnectionstotheInternet.cellularservice(249)Offeranalternativeformobiledevicesandlaptops.client(251)Anodethatrequestsandusesresourcesavailablefromothernodes.client/servernetworksystem(260)Acomputernetworkwhereonecomputercoordinatesandsuppliesservicestoothernodesonthenetwork.coaxialcable(244)Ahigh-frequencytransmissioncablewithasinglesolid-coppercore.Communicationchannel(244)Theactualconnectingortransmissionmediumthatcarriesthemessage.Communicationsystem(243)Anelectronicsystemthattransmitdatafromonelocationtoanothercomputernetwork(251)Acommunicationsystemthatconnectstwoormorecomputerssothattheycanexchangeinformationandshareresources.connectivity(242)Usingcomputernetworkstolinkpeopleandresources.demodulation(247)Theprocessofconvertingfromanalogtodigital.dial-upservice(248)UsingstandardtelephonelinesandconventionalmodemstolinktotheInternetorothercomputersdigitalsignal(247)Arepresentationofthepresenceorabsenceofanelectronicpulse–on/offdigitalsubscriberline(DSL)(248)Usesexistingtelephonelinestoprovidehigh-speedconnectionsdistributeddataprocessingsystemComputersthatcanperformprocessingtasksattheirownComputingEssentials2008Chapter9:CommunicationsandNetworksKeyTermsPage2of6(258)dispersedlocations.distributedprocessing(251)Asysteminwhichcomputingpowerislocatedandsharedatdifferentlocations.domainnameserver(DNS)(250)Convertstext-basedaddressestoIPaddressesEthernet(253)Themostcommonwayinwhichnodescanbeconnectedtooneanotherandcommunicationscanbecontrolled.externalmodem(247)Amodemthatstandsapartfromthecomputerandtypicallyisconnectedbyacabletothecomputer’sserialport.extranet(262)Aprivatenetworkthatconnectsmorethanoneorganization.fiber-opticcable(244)Transmitsdataaspulsesoflightthroughtinytubesofglass.firewall(263)Asecuritysystemdesignedtoprotectanorganization’snetworkagainstexternalthreats.globalpositioningsystem(GPS)(245)Globalpositioningsystem(GPS)devicesuselocationinformationsentbysatellitestouniquelydeterminethegeographiclocationofthedevice.hierarchicalnetwork(258)Consistsofseveralcomputerslinkedtoacentralhostcomputer,butalsoarehoststoother,smallercomputersorperipheraldevices.homenetwork(254)LocalAreaNetworksusedbyindividualsintheirhomesandapartments.hostcomputer(251)Alargecentralizedcomputer,usuallyaminicomputeroramainframe.hub(251)Thecenterorcentralnodeforothernodes.infrared(245)Atypeofwirelessconnectionthatusesinfraredlightwavestocommunicateovershortdistances.internalmodem(248)Amodemthatconsistsofaplug-incircuitboardinsidethesystemunit.intranet(262)AprivatenetworkwithinanorganizationthatresemblestheInternet.IPaddress(InternetProtocoladdress)(250)Auniquenumericaddressforeverycomputeronanetwork.localareanetwork(LAN)(253)Networkswithnodesthatareinclosephysicalproximitylowbandwidth(250)Usedforstandardtelephonecommunication.(seealsovoiceband)mediumband(250)thebandwidthusedinspecialleasedlinestoconnectminicomputersandmainframesmetropolitanareanetwork(MAN)(254)Anetworkthatspandistancesupto100miles.microwave(245)Atypeofcommunicationuseshigh-frequencyradiowaves.modem(247)Modulator-demodulator,enablesdigitalmicrocomputerstocommunicateacrossanalogtelephonelines.modulation(247)Theprocessofconvertingfromdigitaltoanalog.networkadministrator(251,264)Acomputerspecialistresponsibleforefficientnetworkoperationsandimplementationofnewnetworks.networkgateway(253)AdevicethatallowsoneLANtobelinkedtootherLANsortolargernetworks.networkhub(255)Acentralunitinanetwork,suchasaserver.ComputingEssentials2008Chapter9:CommunicationsandNetworksKeyTermsPage3of6networkinterfacecard(NIC)(251)Expansioncardslocatedwithinthesystemunitthatconnectthecomputertoanetworknetworkoperatingsystem(NOS)(251)Anoperatingsystemthatcontrolandcoordinatetheactivitiesofallcomputersandotherdevicesonanetwork.node(251)Anydevicethatisconnectedtoanetwork.packet(250)DatareformattedorbrokendownintosmallpartsPCCardmodem(248)Amodemthatisacreditcar