ISO/IEC 9318的这一部分描述了磁带机的逻辑级（通用级）接口，并提供了称为智能外设接口(IPI)的一系列标准的设备通用部分的定义。 本标准的目的是促进智能接口的开发和利用，该接口允许多种外围设备类型（如磁盘、磁带和与控制器的通信）的互连。 IPI的目的是通过提供“通用功能”命令集来允许多种类型的外围设备（磁盘、打印机、磁带、通信）的连接，从而将主机（CPU）（硬件和软件）与外围设备的变化隔离开来。为了平稳地从当前方法过渡到通用方法，IPI支持设备-特定的命令集有助于弥合这两种方法之间的差距。 为了实现这组目标，IPI的设计包括设备特定命令集和设备通用命令集。特定于设备的命令集提供: 面向设备的控制； 物理数据寻址； ？定时关键操作； 更低的设备成本。 设备通用命令集提供了更高级别的功能和可移植性。它包括: 主机/设备独立性； 逻辑数据寻址； 定时独立性； 命令排队功能。 系统不限于使用一个或另一个级别的命令集。可能的是，两个级别的命令集将与给定系统的体系结构一起使用，以平衡诸如系统性能、成本和外围设备可用性之类的参数。主机也可以提供从设备-特定于设备通用级别，同时仍保留相同的物理接口。 IPI标准系列包括高性能、通用并行外设接口的定义。然而，设备通用命令集也可以通过其他非IPI物理接口传输。ANSI X3.291:1997包含到高性能并行接口（HIPPI）和光纤通道（FC）以及到IPI增强型物理接口的“映射”。本文档中不包含“映射”。

This part of ISO/IEC 9318 describes the logical level (generic level) interface for tape drives and it provides a definition of the device-generic portion of a family of standards called the Intelligent Peripheral Interface (IPI). The purpose of this standard is to facilitate the development and utilization of an intelligent interface which permits the interconnection of multiple peripheral types such as disk, tape and communications to a controller. The intent of the IPI is to isolate the host (CPU), both hardware and software, from changes in peripherals by providing a "function-generic" command set to allow the connection of multiple types of peripherals (disks, printers, tapes, communications). To smooth the transition from the current methods to the generic approach, the IPI supports device-specific command sets to aid in bridging the gap between the two approaches. To accomplish this set of goals, the design of the IPI includes device-specific and devicegeneric command sets. The device-specific command set provides:

• device-oriented control;
• physical data addressing;
• ？timing critical operations;
• lower device cost.

The device-generic command set provides a higher level of functionality and portability. It includes:

• host/device independence;
• logical data addressing;
• timing independence;
• command queuing capability.

A system is not restricted to the use of one level of command set or the other. It is possible that both levels of command sets will be utilized with a given system's architecture to balance such parameters as system performance, cost and peripheral availability. It is also possible for the host to provide for the migration from device-specific to device-generic levels while still retaining the same physical interface. The IPI standards family includes the definition of a high performance, general-purpose parallel peripheral interface. However, the device-generic command set may also be transported over other non-IPI physical interfaces. ANSI X3.291:1997 contains "mappings" to the High-Performance Parallel Interface (HIPPI) and Fibre Channel (FC) as well as to the IPI Enhanced Physical Interface. The "mappings" are not contained in this document.