VxWorks座中文版PPT课件.ppt

.,1,Tornados.value=s.value-1;if(s.valuedevsdrvname0/null1/tyCo/01/tyCo/14columbia:2/pipe/myPipe,.,143,ReadingandWritingtoaPipe,thisisames,thisisamess,thisisames,thisisamessage,fd=open(“/pipe/myPipe”,O_RDWR,0);write(fd,msg,len);,read(fd,msg,len);,.,144,MessageQueuesvs.Pipes,.,145,Summary,msgQCreate()msgQSend()msgQReceive(),.,146,Chapter8,Memory,.,147,MemoryLayout,LOCAL_MEM_LOCAL_ADRS,RAM_LOW-ADRS,FREE_RAM_ADRS,VxWorks,SYSTEMMEMORYPOOL,sysMemTop(),WDB_POOL_SIZE,USER_RESERVED_MEM,sysPhysMemTop(),.,148,TargetServerMemoryPool,.,149,SystemMemoryPool,.,150,Allocating/ReleasingMemory,.,151,DebuggingOptions,.,152,ExaminingMemory,FreeList,mv152-externalmekong:MempartOx,Totalbytes=3870840Allocatedblocks=86bytes=467224Freeblocks=7bytes=3403584Cummulativeblocks=88bytes=467832FreeList0addr=0 x3fd8f8size=96041addr=0 x4ef90size=3355432,.,153,AdditionalSystemMemoryManagementRoutines,void*calloc(nElems,size),Allocatezeroedmemoryforanarray.,void*realloc(ptr,newSize),Resizeanallocatedblock.Theblockmaybemoved.,intmemFindMax(),Returnsthesizeofthelargestfreeblockinsystemmemory.,.,154,FineTuning,messagequeue,ptr,ptr,ptr,.,bufGet(),bufReturn(),.,buffers,.,155,GenericPartitionManager,.,156,CreatingamemoryPartition,PART_IDmemPartCreate(pPool,size)pPoolPointertomemoryforthispartitionsizeSizeofmemorypartitioninbytes.,.,157,ManagingMemoryPartitions,.,158,ExampleCreatingaMemoryPartition,-partId=memPartCreate(pMemory,100000)newsymbol“partId”addedtosymbltable.partId=0 x23ff318:value=37745448=0 x23ff328=partId+0 x10-ptr=memPartAlloc(partId,200)newsymbol“ptr”addedtosymbltable.ptr=0 x23ff2ec:value=37652632=0 x23e8898-showpartIdstatusbytesblocksaveblockmaxblockcurrentfree9977619977699776alloc2081208-cumulativealloc2081208-,.,159,Summary,.,160,Chapter9,Exceptions,InterruptsandTimers,.,161,Exceptions,InterruptsandTimers,ExceptionHandlingandSignals,InterruptServiceRoutines,Timers,.,162,信号(Signals)（一）,VxWorks支持软件信号功能。信号可以异步改变任务控制流。任何任务和ISR都可以向指定的任务发信号。获得信号的任务立即挂起当前的执行，在下次调度它运行时转而执行指定的信号处理程序。信号处理程序在信号接收任务的上下文中执行，使用该任务的堆栈。在任务阻塞时，信号处理程序仍可被唤醒信号机制适合于错误和异常处理。通常，信号处理程序可以作为中断处理程序看待。任何可能导致调用程序阻塞的函数均不能在信号处理程序中调用。Wind内核支持两种类型的信号接口UNIXBSD风格的信号POSIX兼容的信号,.,163,信号(Signals)（二）,信号在很多方面跟硬件中断相似。基本信号接口提供了31个不同的信号。调用sigvec()或sigaction()可为信号指定一个信号处理程序。这与调用intConnect()为中断指定一个中断处理程序(ISR)相似。可以调用kill()将信号发送给任务，这类似于于中断发生。函数sigsetmask()和sigblock或sigprocmask()可以用来象屏蔽中断那样屏蔽信号。使用sigInit()初始化信号函数库，使得基本信号函数可用,.,164,基本信号接口函数,.,165,几个函数原型,intsigvec检测或设置信号处理程序(intsig,/*于处理程序相联系的信号*/conststructsigvec*pVec,/*新的处理程序信息*/structsigvec*pOvec/*旧的处理程序信息*/)intkill向任务发送一个信号(inttid,/*接收信号的任务号*/intsigno/*发送给任务的信号*/)sigqueue提供与kill()等价的功能(inttid,/*接收信号的任务*/intsigno,/*发送给任务的信号*/constunionsigvalvalue/*隋信号发送的值*/),.,166,Signals,normalCode(),.,mySignalHandler(),.,mySignal,.,167,UNIX:UNIXvs.VxWorksSIgnals,PendQ,ReadyQ,Signal,Runsignal-handler,semTake(.OrgDelay),.,168,Caveats,.,169,RegisteringaSignalHandler,signal(signo.handler),signoSignalnumber.,handlerRoutinetoinvokewhensignalarrives(orSIG_IGNtoignoresignal).,Returnsthepreviouslyinstalledsignalhandler,orSIG_ERR.,.,170,SignalsandExceptions,TaskhasSIGSEGVsignalhandlerinstalled?,raisesignal,SuspendtaskLogerrormessage,myCode().,buserror,.,171,TheSignalHandler,.,172,Exceptions,InterruptsandTimers,ExceptionHandlingandSignals,InterruptServiceRoutines,Timers,.,173,中断,硬件中断处理是实时系统设计的最重要、最关键的问题。为了获得尽可能快的中断响应时间，VxWorks的中断处理程序运行在特定的上下文中(在所有任务上下文之外)。因此，中断处理不会涉及任何任务上下文的交换。VxWorks提供函数intConnect()，该函数允许将指定的C函数与任意中断相联系。STATUSintConnect(VOIDFUNCPTR*vector,/*要联系的中断向量*/VOIDFUNCPTR*routine,/*中断发生时要调用的函数*/intparameter/*传递给中断处理函数的参数*/)该函数将指定的C函数routine与指定的中断向量vector相联系，函数的地址存储在这个中断向量里。,.,174,中断函数,.,175,中断处理过程,事件,中断,切换到中断堆栈、保存程序计数器和寄存器,调用inConnect指定的中断处理程序,处理该中断,恢复寄存器、返回,中断向量表,执行顺序,1,255,.,176,中断堆栈,如果体系结构允许，所有的ISRs使用的中断堆栈。堆栈的定位和初始化由系统在启动时根据指定的配置参数完成。堆栈必须足够大，以保证能够处理系统最坏情形下的中断嵌套。体系结构不允许使用一个特定的堆栈。在这种结构中，ISRs使用中断任务的堆栈。对于这种结构的目标机，应用必须创建足够大的堆栈空间。开发过程中，可以调用checkStack()函数察看一个任务堆栈的使用或整个系统堆栈的使用情况。,.,177,ISR的特殊限制,基本约束：必须不能调用可能引起调用阻塞的函数。在中断服务程序中不能试图获取一个信号量，因为信号量可能不可用。中断服务程序里面不能使用malloc和free，因为他们都需要获取一个信号量。中断服务程序也不能通过VxWorks驱动执行I/O操作。多数设备驱动由于可能需要等待设备而引起调用者阻塞，因此需要任务上下文交换。VxWorks支持纪录功能，任务可以向系统输出平台打印文本信息。logMsg(),.,178,Interrupts,.,179,DeviceDrivers,intArchLibToinstalluserdefinedISRs.BoardSupportPackageBoardspecificinterrupthandling.ProgrammersGuideArchitecturespecificinterruptinfo.TornadoUsersGuideSystemmodedebugginginfo.BSPPortingKitOptionalproductforwritingBSPs.VxWorksDeviceDriverWorkshopWriteVMEbusandVxWorksstandarddevicedrivers.,.,180,Handlinganinterrupt,hander,InterruptVectorTable,InterruptServiceRoutine(ISR),UserISR,handler:,saveregisters,callroutine,restoreregisters,RET,Vectornumber,hardware,myISR().,.,181,InterruptsandPriorities,interrupt,interrupt,interrupt,Task,Task,Task,Absolutesystem-WidePriority,InterruptLevel(HardWired),ExecutionOrderControlledbyHardware,ExecutionOrderControlledbyKernel,TaskPriority(Programmable),.,.,182,InterruptStack,intlevel2,intlevel3,intlevel5,InterruptStack,.,183,ISRRestrictions,ISRsarerestrictedfromusingsomeVxWorksfacilities.Inparticulartheycantblock:,.,184,ISRGuidelines,Trytooff-loadasmuchworkaspossibletosometask:,.,185,TypicalISR,.,186,DebuggingISRs,logMsg(foo=%dn,foo,0,0,0,0,0,0);,SendsarequesttotLogTasktodoaprintf()forus,.,187,ExceptionsatInterruptsTime,.,188,Exceptions,InterruptsandTimers,ExceptionHandlingandSignals,InterruptServiceRoutines,Timers,.,189,Timers,.,190,SystemClock,sysClkRateSet(freq)Setstheclockrate.,intsysClkRateGet()Returnstheclockrate,.,191,WatchdogTimers,.,192,CreatingwatchdogTimers,WDOG_IDwdCreate(),Returnswatchdogid,orNULLonerror.,StatuswdSDtart(wdId,delay,pRoutine,parameter),wdIdWatchdogid,returnedfromwdCreate().,delayNumberoftickstodelay,pRoutineRoutinetocallwhendelayhasexpired,parameterArgumenttopasstoroutine,.,193,UsingWatchdog,wdId=wdCreate();wdStart(wdId,DELAY_PERIOD,myWdTsr,0),voidmyWdIsr(intparam)doit(param);wdStart(wdId,DELAY_PERIOD,mywdIsr,0);,.,194,MissedDeadlines,Torecoverfromamisseddeadline:WDOG_IDwdId;voidfoo(void)wdId=wdCreate();/*Mustfinisheachcycleinunder10seconds*/FOREVERwdStart(wdId,Delay_10_SEC,fooISR,0);fooDoWork();voidfooISR(intparam)/*Handlemisseddeadline*/.,.,195,StoppingWatchdogs,STATUSwdCancel(wdId),STATUSwdDelete(wdId),.,196,WatchdogBrowser,.,197,PollingIssues,.,198,PollingCaveats,voidmyWdISR()pollMyDevice();wdStart(myWdId,sysClkRateGet)/15,0);,.,199,AuxillaryClock,sysAuxClkConnect()ConnectISRtoAuxclock,sysAuxClkRateSet()SetAuxclockrate.,sysAuxClkEnable()StartAuxclock.,sysAuxClkDIsable()StopAuxclock,.,200,Summary,.,201,Summary,auxclock,wdtimer,taskDelay,orwdtimer+semGive,Interrupttime,tasktime,lowspeed,highspeed,.,202,I/OSystem,Chapter,10,.,203,Chapter10,I/OSystem,.,204,I/OSystem,Introduction,BasicI/O,Select(),StandardI/O,.,205,I/OSystemInterface,Application,I/OSystem,xxDriver,Device,creat(),open(),close(),read(),write(),ioctl(),xxCreat(),xxOpen(),xxClose(),xxread(),xxWrite(),xxIoctl(),.,206,I/OSystemBenefits,.,207,DriverInstallation,pipeDrv().,.,208,DeviceCreation,Eachdevicedriverhasadevicecreationroutine:,Pipes,CreatedatyourrequestwithpipeDevCreate().,Serialdevices,Createdautomaticallyatsystemstartup(viattyDevCreate().,Remotefilesystems,SeeNetworkBasicsChapter,Localfilesystems,SeeLocalfileSystemschapter.,Third-partydevices,xxDevCreate().,Theseroutineseachinitializeinstancesofaparticulardevicetype.,.,209,Devices,-devs,drv,name,0/null1/tyCo/01/tyCo/14columbia:2/pipe/dream2/pipe/cleaner5/vio,.,210,I/OSystem,Introduction,BasicI/O,Select(),StandardI/O,.,211,FileDescriptors,.,212,StandardInput,StandardOutput,andStandardError,0STD_IN,1STD_OUT,2STD_ERR,3,4,n,:,.,reservedfiledescriptors,FileDescriptorTable,.,213,StandardInput,Output,andError,VoidioGlobalStdSet(stdFd,newFd),Example:fd=open(“columbia:/vx/errLog”,O_RDWR,0);ioGlobalStdSet(STD_ERR,fd);,voidiotaskStdSet(taskId,stdFd,newFd),.,214,AccessingFiles,intopen(name,flags,mode),name,flags,mode,Nameoffiletoopen.,Specifiestypeofaccess:O_RDONLYOpenfileforreadingonly.O_WRONLYOpenfileforwritingonly.O_RDWROpenforreadingandwriting.O_TRUNCTruncatefileonopen.O_CREATCreatefileifitdoesntexist,PermissionsusedwhencreatingafileinanNFSsystem.,.,215,ExaminingtheFileDescriptorTable,-iosFdShow,fdnamedrv,3/tyCo/014(socket)310/pipe/dream212/pipe/cleaner2,.,216,ClosingFiles,STATUSclose(fd),fdFiledescriptorreturnedfromopen()orcreat(),.,217,Read/Write,intread(fd,buffer,nBytes),intwrite(fd,buffer,nBytes),fd,buffer,nBytes,Filedescriptorreturnedbyopen()orcreat().,Addressofbuffer.Willbefilledonaread,copiedtodeviceonwrite.,Maximumnumberofbytestoread/write.,.,218,Ioctl,intioctl(fd,command,arg),fdFiledescriptorreturnedfromopen()orcreat().commandIntegeridentifyingsomedriverspecificcommand.Symbolicconstantstypicallyused.argTypeandvaluedependsoncommand.,.,219,ioctl()Examples,.,220,SettingOptionsforaSerialDevice,status=ioctl(fd,FIOSETOPTIONS,option);,SymbolicconstantsforoptionsmaybeORed:,1OPT_ECHOEchoofinput.2OPT_CRMODConvertntoCR-LFonoutput.4OPT_TANDEMImplementS/Qflowcontrol.8OPT_7_BITStripparitybitfrom8bitinput.16OPT_MON_TRAPRebootonX.32OPT_ABORTRestarttargetshellonC.64OPT_LINEAllowlineeditingbeforen.-0OPT_RAWAlloptionsoff(rawmode).127OPT_TERMINALAlloptionson.,.,221,I/OSystem,Introduction,BasicI/O,Select(),StandardI/O,.,222,Overview,Server,pipe,socket,orserialport,select(),.,223,select(),select调用及宏FD_CLR、FD_ISSET、FD_SET、FD_ZERO用于I/O多路复用。intselect(intwidth,/*numberofbitstoexaminefrom0*/fd_set*pReadFds,/*readfds*/fd_set*pWriteFds,/*writefds*/fd_set*pExceptFds,/*exceptionfdsunsupported*/structtimeval*pTimeout/*maxtimetowait,NULL=forever*/)pReadFds监测是否有字符可以从某个描述符读入pWriteFds监测是否某个描述符准备好了可以立即写入pExceptFds监测是否某个描述符有异常出现FD_SET(fd,2.InitializeDOS_VOL_CONFIGstructure.3.dosFsDevInit(“/DOS”,pBlkDev,pConfig);4.fd=open(“/DOS”,O_WRONLY,0);5.ioctl(fd,FIODISKFORMAT,0);/*ifnecessary*/6.ioctl(fd,FIODISKINIT,0);7.close(fd);,.,253,Configuration:NewFilesystem,TocreateanewDOSfilesystemwithdefaultconfigurationparameters:1.pBlkDev=xxDevCreate(.);2.dosFsMkfs(“/DOS”,pBlkDev);,.,254,Configuration:UsinganExistingFileSystem,1.pBlkDev=xxDevCreate(.);2.pDesc=dosFsDevInit(“/DOS”,pBlkDev,NULL);3.dosFsVolOptionsSet(pDesc,options);/*ifneeded*/,.,255,ContiguousFileSupport,.,256,LocalFilesystems,Overview,DOSFileSystem,RawFileSystem,SCSIDevices,.,257,IntroductiontotheRawFileSystem,.,258,ConfiguringtheRawFileSystem,.,259,RawFSInitialization,.,260,LocalFilesystems,Overview,DOSFileSystem,RawFileSystem,SCSIDevices,.,261,SCSIOverview,.,262,SCSIBus,VxWorks,Controller,TapeDrive,SCSIBus,InitiatorBusId=7,BusId=6,BusId=5LUN=0,BusId=6LUN=3,BusId=6LUN=5,.,263,SCSI-1Restrictions,.,264,SCSI-1Supportconfiguration,.,265,SCSI-2Features,.,266,SCSI-2Supportconfiguration,.,267,InitializingSCSIBlockDevices,#defineINCLUDE_SCSI2,pSysScsiCtrl,scsiPhysDevcreate(pSysScsiCtrl,busId,LUN,.),IncludeSCSI-2SupportinVxWorks,InitializationofSCSIPeripheral,pScsiPhysDev,InitializeLogicalPartition,scsiBlkDevcreate(),pBlkDev,dosFsDevInit(),InitializeFileSystem,.,268,ConfigurationofSCSIDevices,.,269,Configuration:HardDisks,0/*configureWinchesteratbusId=2,LUN=0*/1if(pSpd20=2scsiPhysDevCreate(pSysScsiCtrl,2,0,0,NONE,0,0,0)3=(SCSI_PHYS_DEV*)NULL)45SCSI_DEBUG_MSG(“usrScsiConfig:”6“scsiPhysDevCreatefailed.n”);7returnERROR;89/*createblockdevices*/10if(pSbd0=scsiBlkDevcreate(pSpd20,0 x10000,0)=11NULL)|12(pSbd1=scsiBlkDevcreate(pSpd20,0 x10000,0 x10000)13=NULL)14return(ERROR);15/*Configurefilesystemsonpartitions*/16if(dosFsDevInit(“/sd0/”,pSbd0,NULL)=NULL)|17(rawFsDevInit(“/sd1/”,pSbd1)=NULL)18return(ERROR);19/*Continuewithotherdevices*/,Size,Offset,LUN,BusId,.,270,InitializingSCSISequentialDevices,#defineINCLUDE_SCSI2,pSysScsiCtrl,scsiPhysDevcreate(pSysScsiCtrl,busId,LUN,.),IncludeSCSI-2SupportinVxWorks,InitializationofSCSIPeripheral,pScsiPhysDev,InitializeLogicalPartition,scsiSeqDevcreate(),pSeqDev,tapeFsDevInit(),InitializeFileSystem,.,271,SequentialDevices,SEQ_DEV*scsiSeqDevCreate(pScsiPhysDev),pScsiPhysDevpointertoaSCSI_PHYS_DEVstructurereturnedbyscsiPhysDevCreate(),.,272,TheTapeFileSystem,.,273,TapeFileSystemInitialization,TAPE_VOL_DESC*tapeFsDevInit(devName,pSeqDev,pTapeConfig),devNameVolumenameoftapefilesystemdevicebeingcreated.pSeqDevPointertoaSEQ_DEVreturnedfromsequentialdevicecreationroutine.pTapeConfigPointertoatapeconfigurationstructureTAPE_CONFIG.,.,274,Configuration:SequentialDevices,1/*configureExabyte8mmtapedriveatbusId=4,LUN=0*/2if(pSpd40=scsiPhysDevCreate3(pSysScsiCtrl,4,0,0,NONE,0,0,0)4=(SCSI_PHYS_DEV*)NULL)56SCSI_DEBUG_MSG(“usrScsiConfig:”7”scsiPhysDevCreatefailed.n”);8return(ERROR);910/*configurethesequentialdeviceforthisphysicaldevice*/11if(pSd0=scsiSeqDevcreate(pSpd40)12=(SEQ_DEV*)NULL)1314SCSI_DEBUG_MSG(“usrScsiConfig:”15”scsiSeqDevCreatefailed.n”);16return(ERROR);1718/*initializeatapeFsdevice*/19.20if(tapeFsDevInit(“/tape1/”,pSd0,pTapeConfig)=NULL)21return(ERROR);,.,275,DebuggingTools,-scsiShowIDLUNVendorIdProductIdRev.TypeBlocksBlkSizescsiPhysDev-50ARCHIVEVIPER15021247-0051R000X003CF654,.,276,Summary,.,277,Chapter12,NetworkBasics,.,278,NetworkBasics,Introduction,ConfiguringTheNetwork,RemoteLogin,RemoteCommandExecution,RemoteFileAccess,.,279,NetworkProtocols,.,280,SimpleNetwork,UNIXFileserver,PCHost,VxWorksTarget,ethernet,(VMEbusandseriallinearealsosupported),.,281,Terminology,.,282,ComplexNetwork(Internet),routers,.,283,SharedMemoryNetworkOverview,ETHERNET,UNIX,VxWorksCPU0,VxWorksCPU1,VMEbus,,Network,,,0,Network,.,284,NetworkServices,.,285,NetworkNon-Determinism,TCP/IPisnon-deterministicbecauseof:,.,286,Networking,Introduction,ConfiguringTheNetwork,RemoteLogin,RemoteCommandExecution,RemoteFileAccess,.,287,Routing,.,288,InternetAddresses,.,289,InternetAddressClasses,Class,A,B,C,0,1,0,1,1,0,network7bits,network14bits,network21bits,host24bits,host16bits,host8bits,.,290,InternetAddressExamples,,,Network,CLASSA,1,9,Network,CLASSB,0,5,Network,CLASSC,.,291,AssigningInternetAddresses,NetworkPrefixes,HostNumbers,.,292,Subnets,.,293,SubnetExample,,,0,7,subnetmask:0 xffffff00,subnet,routertooutsideworld,network,subnet,VxWorkstargeton/24subnetmustspecify:inetonethernet(e):0:ffffff00,.,294,inetLib,Routinesformanipulatinginternetaddresses:inet_addr()Convertsdotnotationinternetaddresstoaninteger.inet_lnaof()Returnsthehostportionofaninternetaddress.inet_netof()Returnsthenetworkportionofaninternetaddress.inet_netof_string()Obtainsnetworkportionofaddressasastring.Knowsaboutinterfacesubnetmasks.inet_ntoa_b()ConvertsinternetaddresstoASCIIdotnotation.,.,295,HostNames,hostAdd(hostName,hostAddr),hostShow(),.,296,Example,-hostAdd“styx”,“0”value=0=0 x0-hostAdd“nelson”,“0”value=0=0 x0-hostShowhostnameinetaddressaliaseslocalhostohio1styx0nelsonvalue=0=0 x0,.,297,RoutingTables,epimetheus,janus,mimas,network,2,,,,network,Network,Network,Gateway,Gateway,HostARoutingTable,HostCRoutingTable,,,,,.,298,AddingRoutesinVxWorks,.,299,ADebuggingTool,-routeAdd“”,“54”value=0=0 x0-routeShowROUTENETTABLEdestinationgatewayflagsRefcntUseInterface54300enp0701152enp0ROUTEHOSTTABLEdestinationgatewayflagsRefcntUseInterface500lo0value=73=0 x49=I,.,300,TestingRoutes,STATUSping(host,nPackets,options)-ping“columbia”,1columbiaisalivevalue=0=0 x0-ping“0”,1noanswerfrom0value=-1=0 xffffffff=_end+0 xfff91c4f,.,301,HostConfiguration,.,302,NetworkServices,Introduction,ConfiguringTheNetwork,RemoteLogin,RemoteCommandExecution,RemoteFileAccess,.,303,RemoteLoginandVxWorks,.,304,RemoteLoginandSupportFacilities,.,305,NetworkBasics,Introduction,ConfiguringTheNetwork,RemoteLogin,RemoteCommandExecution,RemoteFileAccess,.,306,ExecutingRemoteCommands,UNIX,VxWorks,RSHserver,RSHclient,shell,shellcmd,socket,.,307,UNIX:RemoteCommandExecution,intrcmd(host,remotePort,localUser,remoteUser,cmd,pFd2)hostHostnameorinetnumber.remotePortRemoteportnumbertoconnectto,typically514(shell).localUserNameoflocaluser.remoteUserUsernameonremotehost.cmdShellcommandstringtoexecute.pFd2Ifnon-zero,asocketforSTD_ERRisreturnedthroughthispointer.,.,308,UNIX:rcmdExample,-unixDate=calloc(300,1)unixDate=0 x23ff264:value=37744912=0 x23ff110-aFd=rcmd(“ohio”,514,”debbie”,”debbie”,”date”,0)newsymbol“aFd”addedtosymboltable.aFd=0 x23fefa0:value=4=0 x4-read(aFd,unixDate,300)value=29=0 x1d-printf(“%sn”,unixDate)MonNov1812:25:45PST1991value=30=0 x1e-close(aFd),.,309,NetworkBasics,Introduction,ConfiguringTheNetwork,RemoteLogin,RemoteCommandExecution,RemoteFileAccess,.,310,RemoteFileAccess,VxWorkscomeswithtwodriverswhichallowaccesstofilesonremotemachines.,.,311,NFS,.,312,NFSOverview,ToaccessfilesonaremotemachineusingNFS:.Exportserversfilesystem:,.Mountthefilesystemontheclient.,.Settheclientsauthenticationparameters.,.,313,1.ExportingtheFileSystem,%mount/dev/sd0aon/type4.2/dev/sd0gon/dinotype4.2styx:/usron/usrtypenfs,VxWorksTarget,Fileserverstyx,/dino,/usr,WorkstationColumbia,/,.,314,2.MountingNFSFilesystems,-nfsMount(“columbia”,“/dino”,“/dinoNfs”)-fd=open(“/dinoNfs/comics/myFile”,2),STATUSnfsMount(host,fileSystem,localName)hostNameofremotehost.fileSystemNameofremotefilesystemtomount(mustbeexportedbyremotehost).localNameLoc