SCSI协议旨在提供高效的对等I/O总线，其主机和外围设备的最大数量由总线宽度（8或16）决定。数据可以异步或同步传输，传输速率主要取决于设备实现和电缆长度。SCSI是一种I/O接口，可在多种介质和传输速率下运行。 这套SCSI标准为许多不同类型的SCSI设备（磁盘、磁带、打印机、扫描仪等）提供了支持，并规定了确保符合标准的SCSI实现之间的互操作性所需的接口、功能和操作。本标准是适用于所有SCSI设备的设备型号的功能描述，并定义了所有SCSI设备的强制性和可选SCSI命令。一致性实现可以使用任何不违反互操作性的设计技术。

The SCSI protocol is designed to provide an efficient peer-to-peer I/O bus with the maximum number of hosts and peripherals determined by the bus width (8 or 16). Data may be transferred asynchronously or synchronously at rates that depend primarily on device implementation and cable length. SCSI is an I/O interface that may be operated over a wide range of media and transfer rates. The set of SCSI standards provides for many different types of SCSI devices (disks, tapes, printers, scanners and many more), and specifies the interfaces, functions, and operations necessary to ensure interoperability between conforming SCSI implementations. This standard is a functional description of a device model that is applicable to all SCSI devices, and defines the SCSI commands that are mandatory and optional for all SCSI devices. Conforming implementations may employ any design technique that does not violate interoperability.