SCSI命令概述(翻译).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 DPO DisablePageOutBit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 NV ForceUnitAccess 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 address Transparenttothecomputersystemanduser 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 GroupNumberUsedtocollectperformancestatisticsofdifferentgroupsofcommandsApplicationA sperformancevs ApplicationsB sperformance 用于收集不同组别命令的执行统计 READ 16 Command ControlStandardSCSIControlBytesDefinedinSAM 4Hasaconsistentlydefinedmeaningacrossallcommands Foundonlyonfixed lengthCDBcommands 翻译 标准SCSI控制字节 WRITE 16 Command OPCode 8AhSpecifiesthecommandWDProtect Varioussettingsregardingthewriteprotectionchecking WRITE 16 Command DPO DisablePageOutBitUsedtooptimizecachingonboardthetargetdeviceSetto1tellsthetargetthatdataatthisLogicalBlockAddressisnotlikelytobeaccessedagaininthenearfutureandthatthetargetcanremoveitfromitslocalcache WRITE 16 Command FUAandFUA NV ForceUnitAccess Non Volatile Usedtooverridethetargetsinternalcachingandforceittoaccessthemedia WRITE 16 Command LogicalBlockAddress LBA TheaddressonthemediumthattheinitiatorwouldliketoreadInternally thetargetconvertstheLBAtoa Cylinder Sector Head address Transparenttothecomputersystemanduser WRITE 16 Command TransferLengthSpecifiesthelengthincontiguouslogicalunitstobetransferredinthiscommandLogicalunitistypically512 bytes 1Block WRITE 16 Command RestrictedforMMC 4UsedfortheMMC 4Versionofthiscommand WRITE 16 Command GroupNumberUsedtocollectperformancestatisticsofdifferentgroupsofcommandsApplicationA sperformancevs ApplicationsB sperformance WRITE 16 Command ControlStandardSCSIControlBytesDefinedinSAM 4Hasaconsistentlydefinedmeaningacrossallcommands Foundonlyonfixed lengthCDBcommands TESTUNITREADYCommand OPCode 00hSpecifiesthecommandControlBitsaretypicallyzeroDefinedinSAM 4Result 6ByteCDBconsistingofentirely0s TESTUNITREADYCommand Also CHECKCONDITION NOTREADY POWERONOCCURED 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 intheeventthatacommandcouldnotbecompletedSomanypossibleproblemsthataqualifierisusedtoexpandthepoolofposs