SCSI命令概述(翻译)

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SCSICommandSetsCommonSCSICommandsinSASReadCommandsREAD(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CommandSCSICommandsinSASWriteCommandsWRITE(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)数据块指定的指令READCAPACITYVERIFYWRITEANDVERIFYREADLONGWRITELONGManymore…StreamingSpecificCommandsLOADUNLOADLOCATE(16)PREVENTALLOWMEDIUMREMOVALREADBLOCKLIMITSREADPOSITIONREWINDSETCAPACITYSPACE(16)READ(16)CommandOP代码:88hSpecifiesthecommand读保护:关于写保护检查的多种设定READ(16)CommandSet

to1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)CommandFUAandFUA_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)CommandLogicalBlockAddress(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)CommandTransferLengthSpecifiesthelengthincontiguouslogicalunitstobetransferredinthiscommandLogicalunitistypically512-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)CommandRestrictedforMMC-4UsedfortheMMC-4VersionofthiscommandREAD(16)CommandGroupNumberUsedtocollectperformancestatisticsofdifferentgroupsofcommandsApplicationA’sperformancevs.ApplicationsB’sperformance用于收集不同组别命令的执行统计READ(16)CommandControlStandardSCSIControlBytesDefinedinSAM-4Hasaconsistentlydefinedmeaningacrossallcommands\Foundonlyonfixed-lengthCDBcommands翻译：标准SCSI控制字节WRITE(16)CommandOPCode:8AhSpecifiesthecommandWDProtect:VarioussettingsregardingthewriteprotectioncheckingWRITE(16)CommandWRITE(16)CommandFUAandFUA_NV–ForceUnitAccess(Non-Volatile)UsedtooverridethetargetsinternalcachingandforceittoaccessthemediaWRITE(16)CommandLogicalBlockAddress(LBA)TheaddressonthemediumthattheinitiatorwouldliketoreadInternally,thetargetconvertstheLBAtoa(Cylinder,Sector,Head)address–TransparenttothecomputersystemanduserWRITE(16)CommandTransferLengthSpecifiesthelengthincontiguouslogicalunitstobetransferredinthiscommandLogicalunitistypically512-bytes(1Block)WRITE(16)CommandRestrictedforMMC-4UsedfortheMMC-4VersionofthiscommandWRITE(16)CommandGroupNumberUsedtocollectperformancestatisticsofdifferentgroupsofcommandsApplicationA’sperformancevs.ApplicationsB’sperformanceWRITE(16)CommandControlStandardSCSIControlBytesDefinedinSAM-4Hasaconsistentlydefinedmeaningacrossallcommands\Foundonlyonfixed-lengthCDBcommandsOPCode:00hSpecifiesthecommandControlBitsaretypicallyzeroDefinedinSAM-4Result:6ByteCDBconsistingofentirely0sAlso: CHECKCONDITION–NOTREADY–POWERONOCCUREDINQUIRYCommandOPCode: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INQUIRYCommandPageCode: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REPORTLUNSCommandOPCode:A0hSpecifiesthecommandSelectReport:REPORTLUNSCommandAllocationLengthshouldbeatleast16bytesIftheallocationlengthisinsufficienttoreportalltheLUNsonthedevice,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AdditionalSenseCodesValuesreturnedinaResponseFr