Processor speedsindicatetheinternalclock speedof themicroprocessor;other factorsalso affectapplicationperformance.
CD-ROMdrivespeeds listthevariablereadrate.Actualspeedsvaryandareoften lessthanthemaximumpossible.
When referringto processorstorage,realandvirtualstorage,or channelvolume, KBstandsfor approximately1000bytes,MB standsforapproximately1000000 bytes,andGBstandsforapproximately 1000000000bytes.
When referringto harddiskdrive capacityorcommunicationsvolume,MB stands for 1000000bytes,andGBstandsfor1000000000bytes.Totaluser-accessible capacitymay varydependingonoperating environments.
Maximuminternalharddiskdrivecapacitiesassumethereplacementof any standard harddiskdrivesandpopulationof allharddiskdrivebayswiththelargest currently supporteddrivesavailablefromIBM.
Maximummemorymay requirereplacementof thestandardmemorywithan optional memorymodule.
IBMmakesnorepresentationor warrantiesregardingnon-IBMproducts and servicesthatareServerProven®®,includingbutnotlimited totheimpliedwarranties of merchantabilityandfitness foraparticularpurpose.Theseproductsareoffered andwarrantedsolelybythirdparties.
Unlessotherwisestated,IBMmakesnorepresentations orwarrantieswithrespect to non-IBMproducts.Support(if any)forthenon-IBMproductsisprovidedbythe third party,notIBM.
Some softwaremaydifferfromitsretail version(ifavailable),andmay notinclude user manualsorallprogramfunctionality.
Glossary
Thisglossaryprovidesdefinitions forthe terminologyandabbreviationsusedinIBM TotalStorageDS4000publications.
Ifyoudonotfindthetermyou arelooking for,see theIBMGlossaryof ComputingTermslocatedat thefollowingWebsite:
www.ibm.com/ibm/terminology
Thisglossaryalsoincludestermsanddefinitions from:
v InformationTechnologyVocabularyby
Subcommittee1,JointTechnicalCommittee1, of theInternational Organizationfor
StandardizationandtheInternational ElectrotechnicalCommission(ISO/IEC JTC1/SC1).Definitionsareidentifiedbythe symbol (I)afterthedefinition;definitions taken fromdraftinternationalstandards,committee drafts,andworkingpapersbyISO/IEC
JTC1/SC1areidentifiedbythesymbol (T)after thedefinition,indicatingthatfinal agreement hasnotyetbeenreachedamongthe participatingNationalBodiesof SC1.
v IBMGlossaryofComputing Terms.NewYork:
McGraw-Hill,1994.
Thefollowingcross-referenceconventionsare usedinthisglossary:
See Refersyouto(a) atermthatisthe expandedformof anabbreviationor acronym,or(b) asynonymormore preferredterm.
Seealso
Refersyoutoa relatedterm.
AbstractWindowingToolkit(AWT). AJavagraphical userinterface(GUI).
acceleratedgraphicsport(AGP). Abusspecification thatgiveslow-cost3Dgraphicscardsfasteraccessto mainmemoryonpersonalcomputersthantheusual peripheralcomponentinterconnect(PCI)bus.AGP reducestheoverallcostofcreatinghigh-endgraphics subsystemsbyusingexistingsystemmemory.
accessvolume. Aspeciallogicaldrivethatallowsthe host-agenttocommunicatewiththecontrollersinthe storagesubsystem.
adapter. Aprintedcircuitassemblythattransmitsuser datainput/output(I/O)betweentheinternalbusofthe
hostsystemandtheexternalfibre-channel(FC)linkand viceversa.AlsocalledanI/Oadapter,hostadapter,or FCadapter.
advancedtechnology(AT®)busarchitecture. Abus standardforIBMcompatibles.ItextendstheXT™bus architectureto16bitsandalsoallowsforbus mastering,althoughonlythefirst16MBofmain memoryareavailablefordirectaccess.
agent. Aserverprogramthatreceivesvirtual connectionsfromthenetworkmanager(theclient program)inaSimpleNetworkManagement
Protocol-TransmissionControlProtocol/InternetProtocol (SNMP-TCP/IP)network-managingenvironment.
AGP. Seeacceleratedgraphicsport.
AL_PA. Seearbitratedloopphysicaladdress.
arbitratedloop. Oneofthreeexistingfibre-channel topologies,inwhich2-126portsareinterconnected seriallyinasingleloopcircuit.AccesstotheFibre Channel-ArbitratedLoop(FC-AL)iscontrolledbyan arbitrationscheme.TheFC-ALtopologysupportsall classesofserviceandguaranteesin-orderdeliveryof FCframeswhentheoriginatorandresponderareon thesameFC-AL.Thedefaulttopologyforthediskarray isarbitratedloop.Anarbitratedloopissometimes referredtoasaStealthMode.
arbitratedloopphysicaladdress(AL_PA). An8-bit valuethatisusedtouniquelyidentifyanindividualport withinaloop.AloopcanhaveoneormoreAL_PAs.
array. Acollectionoffibre-channelorSATAharddrives thatarelogicallygroupedtogether.Allthedrivesinthe arrayareassignedthesameRAIDlevel.Anarrayis sometimesreferredtoasa″RAIDset.″Seealso redundantarrayofindependentdisks(RAID),RAID level.
asynchronouswritemode. Inremotemirroring,an optionthatallowstheprimarycontrollertoreturnawrite I/Orequestcompletiontothehostserverbeforedata hasbeensuccessfullywrittenbythesecondary controller.Seealsosynchronouswritemode,remote mirroring,GlobalCopy,GlobalMirroring.
AT. Seeadvancedtechnology(AT)busarchitecture.
ATA. SeeAT-attached.
AT-attached. Peripheraldevicesthatarecompatible withtheoriginalIBMATcomputerstandardinwhich signalsona40-pinAT-attached(ATA)ribboncable followedthetimingsandconstraintsoftheIndustry StandardArchitecture(ISA)systembusontheIBMPC ATcomputer.Equivalenttointegrateddriveelectronics (IDE).
auto-volumetransfer/auto-disktransfer(AVT/ADT).
Afunctionthatprovidesautomaticfailoverincaseof controllerfailureonastoragesubsystem.
AVT/ADT. Seeauto-volumetransfer/auto-disktransfer.
AWT. SeeAbstractWindowingToolkit.
basicinput/outputsystem(BIOS). Thepersonal computercodethatcontrolsbasichardwareoperations, suchasinteractionswithdiskettedrives,harddisk drives,andthekeyboard.
BIOS. Seebasicinput/outputsystem.
BOOTP. Seebootstrapprotocol.
bootstrapprotocol(BOOTP). InTransmissionControl Protocol/InternetProtocol(TCP/IP)networking,an alternativeprotocolbywhichadisklessmachinecan obtainitsInternetProtocol(IP)addressandsuch configurationinformationasIPaddressesofvarious serversfromaBOOTPserver.
bridge. Astorageareanetwork(SAN)devicethat providesphysicalandtransportconversion,suchas FibreChanneltosmallcomputersysteminterface (SCSI)bridge.
bridgegroup. Abridgeandthecollectionofdevices connectedtoit.
broadcast. Thesimultaneoustransmissionofdatato morethanonedestination.
cathoderaytube(CRT). Adisplaydeviceinwhich controlledelectronbeamsareusedtodisplay alphanumericorgraphicaldataonan electroluminescentscreen.
client. Acomputersystemorprocessthatrequestsa serviceofanothercomputersystemorprocessthatis typicallyreferredtoasaserver.Multipleclientscan shareaccesstoacommonserver.
command. Astatementusedtoinitiateanactionor startaservice.Acommandconsistsofthecommand nameabbreviation,anditsparametersandflagsif applicable.Acommandcanbeissuedbytypingitona commandlineorselectingitfromamenu.
communitystring. Thenameofacommunity containedineachSimpleNetworkManagement Protocol(SNMP)message.
concurrentdownload. Amethodofdownloadingand installingfirmwarethatdoesnotrequiretheusertostop I/Otothecontrollersduringtheprocess.
CRC. Seecyclicredundancycheck.
CRT. Seecathoderaytube.
CRU. Seecustomerreplaceableunit.
customerreplaceableunit(CRU). Anassemblyor partthatacustomercanreplaceinitsentiretywhenany ofitscomponentsfail.Contrastwithfieldreplaceable unit(FRU).
cyclicredundancycheck(CRC). (1)Aredundancy checkinwhichthecheckkeyisgeneratedbyacyclic algorithm.(2)Anerrordetectiontechniqueperformedat boththesendingandreceivingstations.
dac. Seediskarraycontroller.
dar. Seediskarrayrouter.
DASD. Seedirectaccessstoragedevice.
datastriping. Seestriping.
defaulthostgroup. Alogicalcollectionofdiscovered hostports,definedhostcomputers,anddefinedhost groupsinthestorage-partitiontopologythatfulfillthe followingrequirements:
v Arenotinvolvedinspecificlogicaldrive-to-LUN mappings
v
Shareaccesstologicaldriveswithdefaultlogical drive-to-LUNmappings
devicetype. Identifierusedtoplacedevicesinthe physicalmap,suchastheswitch,hub,orstorage.
DHCP. SeeDynamicHostConfigurationProtocol.
directaccessstoragedevice(DASD). Adevicein whichaccesstimeiseffectivelyindependentofthe locationofthedata.Informationisenteredandretrieved withoutreferencetopreviouslyaccesseddata.(For example,adiskdriveisaDASD,incontrastwithatape drive,whichstoresdataasalinearsequence.)DASDs includebothfixedandremovablestoragedevices.
directmemoryaccess(DMA). Thetransferofdata betweenmemoryandaninput/output(I/O)device withoutprocessorintervention.
diskarraycontroller(dac). Adiskarraycontroller devicethatrepresentsthetwocontrollersofanarray.
Seealsodiskarrayrouter.
diskarrayrouter(dar). Adiskarrayrouterthat representsanentirearray,includingcurrentand
deferredpathstoalllogicalunitnumbers(LUNs)(hdisks onAIX).Seealsodiskarraycontroller.
DMA. Seedirectmemoryaccess.
domain. Themostsignificantbyteinthenodeport (N_port)identifierforthefibre-channel(FC)device.Itis notusedintheFibreChannel-smallcomputersystem interface(FC-SCSI)hardwarepathID.Itisrequiredto bethesameforallSCSItargetslogicallyconnectedto anFCadapter.
drivechannels. TheDS4200,DS4700,andDS4800 subsystemsusedual-portdrivechannelsthat,fromthe physicalpointofview,areconnectedinthesameway astwodriveloops.However,fromthepointofviewof thenumberofdrivesandenclosures,theyaretreated asasingledriveloopinsteadoftwodifferentdrive loops.Agroupofstorageexpansionenclosuresare connectedtotheDS4000storagesubsystemsusinga drivechannelfromeachcontroller.Thispairofdrive channelsisreferredtoasaredundantdrivechannel pair.
driveloops. Adriveloopconsistsofonechannelfrom eachcontrollercombinedtoformonepairofredundant drivechannelsoraredundantdriveloop.Eachdrive loopisassociatedwithtwoports.(Therearetwodrive channelsandfourassociatedportspercontroller.)For theDS4800,driveloopsaremorecommonlyreferredto asdrivechannels.Seedrivechannels.
DRAM. Seedynamicrandomaccessmemory.
DynamicHostConfigurationProtocol(DHCP). A protocoldefinedbytheInternetEngineeringTaskForce thatisusedfordynamicallyassigningInternetProtocol (IP)addressestocomputersinanetwork.
dynamicrandomaccessmemory(DRAM). A storageinwhichthecellsrequirerepetitiveapplication ofcontrolsignalstoretainstoreddata.
ECC. Seeerrorcorrectioncoding.
EEPROM. Seeelectricallyerasableprogrammable read-onlymemory.
EISA. SeeExtendedIndustryStandardArchitecture.
electricallyerasableprogrammableread-only memory(EEPROM). Atypeofmemorychipwhichcan retainitscontentswithoutconsistentelectricalpower.
UnlikethePROMwhichcanbeprogrammedonlyonce, theEEPROMcanbeerasedelectrically.Becauseitcan onlybereprogrammedalimitednumberoftimesbefore itwearsout,itisappropriateforstoringsmallamounts ofdatathatarechangedinfrequently.
electrostaticdischarge(ESD). Theflowofcurrent thatresultswhenobjectsthathaveastaticcharge comeintocloseenoughproximitytodischarge.
environmentalservicemodule(ESM)canister. A componentinastorageexpansionenclosurethat monitorstheenvironmentalconditionofthecomponents inthatenclosure.NotallstoragesubsystemshaveESM canisters.
E_port. Seeexpansionport.
errorcorrectioncoding(ECC). Amethodfor encodingdatasothattransmissionerrorscanbe detectedandcorrectedbyexaminingthedataonthe
receivingend.MostECCsarecharacterizedbythe maximumnumberoferrorstheycandetectandcorrect.
ESD. Seeelectrostaticdischarge.
ESMcanister. Seeenvironmentalservicemodule canister.
automaticESMfirmwaresynchronization. When youinstallanewESMintoanexistingstorage expansionenclosureinaDS4000storagesubsystem thatsupportsautomaticESMfirmwaresynchronization, thefirmwareinthenewESMisautomatically
synchronizedwiththefirmwareintheexistingESM.
EXP. Seestorageexpansionenclosure.
expansionport(E_port). Aportthatconnectsthe switchesfortwofabrics.
ExtendedIndustryStandardArchitecture(EISA). A busstandardforIBMcompatiblesthatextendsthe IndustryStandardArchitecture(ISA)busarchitectureto 32bitsandallowsmorethanonecentralprocessing unit(CPU)tosharethebus.SeealsoIndustryStandard Architecture.
fabric. AFibreChannelentitywhichinterconnectsand facilitatesloginsofN_portsattachedtoit.Thefabricis responsibleforroutingframesbetweensourceand destinationN_portsusingaddressinformationinthe frameheader.Afabriccanbeassimpleasa point-to-pointchannelbetweentwoN-ports,oras complexasaframe-routingswitchthatprovidesmultiple andredundantinternalpathwayswithinthefabric betweenF_ports.
fabricport(F_port). Inafabric,anaccesspointfor connectingauser’sN_port.AnF_portfacilitatesN_port loginstothefabricfromnodesconnectedtothefabric.
AnF_portisaddressablebytheN_portconnectedtoit.
Seealsofabric.
FC. SeeFibreChannel.
FC-AL. Seearbitratedloop.
featureenableidentifier. Auniqueidentifierforthe storagesubsystem,whichisusedintheprocessof generatingapremiumfeaturekey.Seealsopremium featurekey.
FibreChannel(FC). Asetofstandardsforaserial input/output(I/O)buscapableoftransferringdata betweentwoportsatupto100Mbps,withstandards proposalstogotohigherspeeds.FCsupports point-to-point,arbitratedloop,andswitchedtopologies.
FibreChannel-ArbitratedLoop(FC-AL). See arbitratedloop.
FibreChannelProtocol(FCP)forsmallcomputer systeminterface(SCSI). Ahigh-levelfibre-channel mappinglayer(FC-4)thatuseslower-levelfibre-channel
(FC-PH)servicestotransmitSCSIcommands,data, andstatusinformationbetweenaSCSIinitiatoranda SCSItargetacrosstheFClinkbyusingFCframeand sequenceformats.
fieldreplaceableunit(FRU). Anassemblythatis replacedinitsentiretywhenanyoneofitscomponents fails.Insomecases,afieldreplaceableunitmight containotherfieldreplaceableunits.Contrastwith customerreplaceableunit(CRU).
FlashCopy. ApremiumfeatureforDS4000thatcan makeaninstantaneouscopyofthedatainavolume.
F_port. Seefabricport.
FRU. Seefieldreplaceableunit.
GBIC. Seegigabitinterfaceconverter
gigabitinterfaceconverter(GBIC). Atransceiverthat performsserial,optical-to-electrical,and
electrical-to-opticalsignalconversionsforhigh-speed networking.AGBICcanbehotswapped.Seealso smallform-factorpluggable.
GlobalCopy. Referstoaremotelogicaldrivemirror pairthatissetupusingasynchronouswritemode withoutthewriteconsistencygroupoption.Thisisalso referredtoas″AsynchronousMirroringwithout
ConsistencyGroup.″GlobalCopydoesnotensurethat writerequeststomultipleprimarylogicaldrivesare carriedoutinthesameorderonthesecondarylogical drivesastheyareontheprimarylogicaldrives.Ifitis criticalthatwritestotheprimarylogicaldrivesare carriedoutinthesameorderintheappropriate secondarylogicaldrives,GlobalMirroringshouldbe usedinsteadofGlobalCopy.Seealsoasynchronous writemode,GlobalMirroring,remotemirroring,Metro Mirroring.
GlobalMirroring. Referstoaremotelogicaldrive mirrorpairthatissetupusingasynchronouswritemode withthewriteconsistencygroupoption.Thisisalso referredtoas″AsynchronousMirroringwithConsistency Group.″GlobalMirroringensuresthatwriterequeststo multipleprimarylogicaldrivesarecarriedoutinthe sameorderonthesecondarylogicaldrivesastheyare ontheprimarylogicaldrives,preventingdataonthe secondarylogicaldrivesfrombecominginconsistent withthedataontheprimarylogicaldrives.Seealso asynchronouswritemode,GlobalCopy,remote mirroring,MetroMirroring.
graphicaluserinterface(GUI). Atypeofcomputer interfacethatpresentsavisualmetaphorofareal-world scene,oftenofadesktop,bycombininghigh-resolution graphics,pointingdevices,menubarsandothermenus, overlappingwindows,icons,andtheobject-action relationship.
GUI. Seegraphicaluserinterface.
HBA. Seehostbusadapter.
hdisk. AnAIXtermrepresentingalogicalunitnumber (LUN)onanarray.
heterogeneoushostenvironment. Ahostsystemin whichmultiplehostservers,whichusedifferent operatingsystemswiththeirownuniquediskstorage subsystemsettings,connecttothesameDS4000 storagesubsystematthesametime.Seealsohost.
host. Asystemthatisdirectlyattachedtothestorage subsystemthroughafibre-channelinput/output(I/O) path.Thissystemisusedtoservedata(typicallyinthe formoffiles)fromthestoragesubsystem.Asystemcan bebothastoragemanagementstationandahost simultaneously.
hostbusadapter(HBA). Aninterfacebetweenthe fibre-channelnetworkandaworkstationorserver.
hostcomputer. Seehost.
hostgroup. Anentityinthestoragepartitiontopology thatdefinesalogicalcollectionofhostcomputersthat requiresharedaccesstooneormorelogicaldrives.
hostport. Portsthatphysicallyresideonthehost adaptersandareautomaticallydiscoveredbythe DS4000StorageManagersoftware.Togiveahost computeraccesstoapartition,itsassociatedhostports mustbedefined.
hotswap. Toreplaceahardwarecomponentwithout turningoffthesystem.
hub. Inanetwork,apointatwhichcircuitsareeither connectedorswitched.Forexample,inastarnetwork, thehubisthecentralnode;inastar/ringnetwork,itis thelocationofwiringconcentrators.
IBMSANdriver. Thedevicedriverthatisusedina NovellNetWareenvironmenttoprovidemultipath input/output(I/O)supporttothestoragecontroller.
IC. Seeintegratedcircuit.
IDE. Seeintegrateddriveelectronics.
in-band. Transmissionofmanagementprotocolover thefibre-channeltransport.
IndustryStandardArchitecture(ISA). Unofficial nameforthebusarchitectureoftheIBMPC/XT™ personalcomputer.Thisbusdesignincludedexpansion slotsforplugginginvariousadapterboards.Early versionshadan8-bitdatapath,laterexpandedto16 bits.The″ExtendedIndustryStandardArchitecture″ (EISA)furtherexpandedthedatapathto32bits.See alsoExtendedIndustryStandardArchitecture.
initialprogramload(IPL). Theinitializationprocedure thatcausesanoperatingsystemtocommence
operation.Alsoreferredtoasasystemrestart,system startup,andboot.
integratedcircuit(IC). Amicroelectronic semiconductordevicethatconsistsofmany
interconnectedtransistorsandothercomponents.ICs areconstructedonasmallrectanglecutfromasilicon crystalorothersemiconductormaterial.Thesmallsize ofthesecircuitsallowshighspeed,lowpower
dissipation,andreducedmanufacturingcostcompared withboard-levelintegration.Alsoknownasachip.
integrateddriveelectronics(IDE). Adiskdrive interfacebasedonthe16-bitIBMpersonalcomputer IndustryStandardArchitecture(ISA)inwhichthe controllerelectronicsresideonthedriveitself, eliminatingtheneedforaseparateadaptercard.Also knownasanAdvancedTechnologyAttachment Interface(ATA).
InternetProtocol(IP). Aprotocolthatroutesdata throughanetworkorinterconnectednetworks.IPacts asanintermediarybetweenthehigherprotocollayers andthephysicalnetwork.
InternetProtocol(IP)address. Theunique32-bit addressthatspecifiesthelocationofeachdeviceor workstationontheInternet.Forexample,9.67.97.103is anIPaddress.
interruptrequest(IRQ). Atypeofinputfoundon manyprocessorsthatcausestheprocessortosuspend normalprocessingtemporarilyandstartrunningan interrupthandlerroutine.Someprocessorshaveseveral interruptrequestinputsthatallowdifferentpriority interrupts.
IP. SeeInternetProtocol.
IPL. Seeinitialprogramload.
IRQ. Seeinterruptrequest.
IRQ. Seeinterruptrequest.