ISO/IEC 14776的这一部分定义了命令集扩展，以便于SCSI的操作 阻止设备。 它指定了SCSI块命令集（SBC）的功能要求。SBC许可证 连接SCSI块逻辑单元，如软盘、硬盘、光盘等 并为它们的使用提供了定义。 本标准定义了SCSI块逻辑单元的逻辑单元模型。还定义了SCSI 适用于SCSI块逻辑单元的命令。 本标准中与SCSI块设备类相关的条款，在 结合ISO/IEC 14776-311的适用条款，全面规定标准 SCSI块设备的命令集。 本标准的目标如下: a)允许应用客户端与声明其自身为 器件类型领域中的直接存取器件、一次写入器件和光存储器件 所述查询命令响应数据通过SCSI服务传递子系统； b)定义特定于SCSI块设备类型的命令； c)定义命令以管理SCSI块设备的操作； d)定义SCSI块设备类型之间的差异。 图1？SCSI标准？总体结构 图1显示了SCSI标准的一般结构。该图并不意味着 关系，如层次结构、协议栈或系统架构。它表明 标准对给定传输实现的适用性。

This part of ISO/IEC 14776 defines the command set extensions to facilitate operation of SCSI block devices. It specifies the functional requirements for the SCSI-Block Command set (SBC). SBC permits that SCSI block logical units, such as flexible disks, rigid disks, optical disks, etc. be attached to computers, and it provides the definition for their use. This standard defines a logical unit model for SCSI block logical units. Also defined are SCSI commands that apply to SCSI block logical units. The clause(s) of this standard pertaining to the SCSI block device class, implemented in conjunction with the applicable clauses of ISO/IEC 14776-311, fully specify the standard command set for SCSI block devices. The objectives of this standard are the following: a) permit an application client to communicate with a logical unit that declares itself to be a direct-access device, write-once device and optical memory device in the device type field of the INQUIRY command response data over an SCSI service delivery subsystem; b) define commands unique to the type of SCSI block devices; c) define commands to manage the operation of SCSI block devices; d) define the differences between types of SCSI block devices.

Figure 1?SCSI standards?General structure Figure 1 shows the general structure of SCSI standards. The figure does not imply a relationship such as a hierarchy, protocol stack, or system architecture. It indicates the applicability of a standard to the implementation of a given transport.