SCSI命令概述翻译课件.ppt

UNH互操作性实验室,SCSI命令概述,物理,物理层,数据链路层,数据传输层,应用层,陈述主题,命令摘要命令选择释义附加意义上的代码及资格,CDB,命令数据程序块命令由CDBs定义每个对象都有他自己的CDBCDBs由多种SCSI标准定义拥有固定和变化的长度变量InSAS:囊括在一个指令框架中,SCSICommandSets,SPC-4SCSIPrimaryCommandsVersion4命令对于所有的方法类型普遍适用SBC-3SCSIBlockCommandVersion3命令针对特定的块设备(硬盘)SSC-2SCSIStreamingCommandsVersion2命令针对特定的流设备(磁盘驱动)MMC-4SCSIMultiMediaCommandsVersion4命令针对特定的多媒体设备(CD/DVD),CommonSCSICommandsinSAS,ReadCommandsREAD(6)(SSCandSBC)*READ(10)(SBC)READ(12)(SBC)READ(16)(SBC)READ(32)(SBC)*不同的域定义使用相同的CDB长度,CommandSCSICommandsinSAS,WriteCommandsWRITE(6)(SSCandSBC)*WRITE(10)(SBC)WRITE(12)(SBC)WRITE(16)(SBC)WRITE(32)(SBC)*DifferentFieldDefinitions,sameCDBLength,诊断与初始化指令,读缓冲(SPC)写缓冲(SPC)询问(SPC)测试单元就绪(SPC)模式识别(SPC)模式选择(SPC)日志识别(SPC)日志选择(SPC)读取归类(SPC)REPORTLUNS(SPC),READBUFFER(SPC)WRITEBUFFER(SPC)INQUIRY(SPC)TESTUNITREADY(SPC)MODESENSE(SPC)MODESELECT(SPC)LOGSENSE(SPC)LOGSELECT(SPC)READATTRIUBUTE(SPC)REPORTLUNS(SPC),数据块指定的指令,READCAPACITYVERIFYWRITEANDVERIFYREADLONGWRITELONGManymore,StreamingSpecificCommands,LOADUNLOADLOCATE(16)PREVENTALLOWMEDIUMREMOVALREADBLOCKLIMITSREADPOSITIONREWINDSETCAPACITYSPACE(16),READ(16)Command,OP代码:88hSpecifiesthecommand读保护:关于写保护检查的多种设定,READ(16)Command,DPODisablePageOutBit用于最优化登录目标设备的缓存Setto1tellsthetargetthatdataatthisLogicalBlockAddressisnotlikelytobeaccessedagaininthenearfutureandthatthetargetcanremoveitfromitslocalcache,Setto1告诉目标在这个逻辑区块地址中的数据在不久的将来无法再次接近并且目标可在将它从它的本地缓存中移除,READ(16)Command,FUAandFUA_NVForceUnitAccess(Non-Volatile)Usedtooverridethetargetsinternalcachingandforceittoaccessthemedia,适用于目标内部缓存并且指示其接近媒介,READ(16)Command,LogicalBlockAddress(LBA)TheaddressonthemediumthattheinitiatorwouldliketoreadInternally,thetargetconvertstheLBAtoa(Cylinder,Sector,Head)addressTransparenttothecomputersystemanduser,逻辑区块地址,在内部，对象将LBA转化成一个地址，此地址对计算机系统和用户而言显而易见,READ(16)Command,TransferLengthSpecifiesthelengthincontiguouslogicalunitstobetransferredinthiscommandLogicalunitistypically512-bytes(1Block),本地单元使典型的512字节（1数据块）,在此对象中指定在临近逻辑单元上被转移的长度,READ(16)Command,RestrictedforMMC-4UsedfortheMMC-4Versionofthiscommand,READ(16)Command,GroupNumberUsedtocollectperformancestatisticsofdifferentgroupsofcommandsApplicationAsperformancevs.ApplicationsBsperformance,用于收集不同组别命令的执行统计,READ(16)Command,ControlStandardSCSIControlBytesDefinedinSAM-4HasaconsistentlydefinedmeaningacrossallcommandsFoundonlyonfixed-lengthCDBcommands,翻译：标准SCSI控制字节,2019/12/19,19,可编辑,WRITE(16)Command,OPCode:8AhSpecifiesthecommandWDProtect:Varioussettingsregardingthewriteprotectionchecking,WRITE(16)Command,DPODisablePageOutBitUsedtooptimizecachingonboardthetargetdeviceSetto1tellsthetargetthatdataatthisLogicalBlockAddressisnotlikelytobeaccessedagaininthenearfutureandthatthetargetcanremoveitfromitslocalcache,WRITE(16)Command,FUAandFUA_NVForceUnitAccess(Non-Volatile)Usedtooverridethetargetsinternalcachingandforceittoaccessthemedia,WRITE(16)Command,LogicalBlockAddress(LBA)TheaddressonthemediumthattheinitiatorwouldliketoreadInternally,thetargetconvertstheLBAtoa(Cylinder,Sector,Head)addressTransparenttothecomputersystemanduser,WRITE(16)Command,TransferLengthSpecifiesthelengthincontiguouslogicalunitstobetransferredinthiscommandLogicalunitistypically512-bytes(1Block),WRITE(16)Command,RestrictedforMMC-4UsedfortheMMC-4Versionofthiscommand,WRITE(16)Command,GroupNumberUsedtocollectperformancestatisticsofdifferentgroupsofcommandsApplicationAsperformancevs.ApplicationsBsperformance,WRITE(16)Command,ControlStandardSCSIControlBytesDefinedinSAM-4HasaconsistentlydefinedmeaningacrossallcommandsFoundonlyonfixed-lengthCDBcommands,TESTUNITREADYCommand,OPCode:00hSpecifiesthecommandControlBitsaretypicallyzeroDefinedinSAM-4Result:6ByteCDBconsistingofentirely0s,TESTUNITREADYCommand,Also:CHECKCONDITIONNOTREADYPOWERONOCCURED,INQUIRYCommand,OPCode:12hSpecifiestheCommandEVPD:EnableVitalProductDataSettozero,thedevicereturnsstandardinquirydataSettoone,enablesthepagecodefield,设置为0，设备返回普通的询问信息,设置为1，启用页面代码字段,INQUIRYCommand,PageCode:Specifiesthepagecodetoreturn.PagesaredefinedinSAM-4,SPC-4,andtechnologyspecificstandardsAllocationLengthspecifiesthelengthofinquirydatatheinitiatorispreparedtoacceptinbytes,定位长度决定了发起者准备接收的询问信息的长度,REPORTLUNSCommand,OPCode:A0hSpecifiesthecommandSelectReport:,REPORTLUNSCommand,AllocationLengthshouldbeatleast16bytesIftheallocationlengthisinsufficienttoreportalltheLUNsonthedevice,thedeviceshallreportonlywhatitisabletoreport,翻译：定位长度至少要有16字节,翻译：如果定位长度不足以报告设备上所有的逻辑单元，硬盘应该只报告它可以报告的单元,AdditionalSenseCodes,ValuesreturnedinaResponseFrame(SAS)intheeventthatacommandcouldnotbecompletedSomanypossibleproblemsthataqualifierisusedtoexpandthepoolofpossiblereturns,翻译：在一