flis part of ISO/IEC 9318 describes the Logicai Level 3 (generic level) Interface for tape drives. See clause 6 of the 〓O/IEC 9318-1 for an explanation of the levels.
The physical, electrical, and configuration characteristics and the transmission protoeol of this interface are in accordance with ISO/IEC 9318-1. The interface is capable of handling data rates from 0 to at least 10 Moctets/s per second, depending on driver and receiver classes.
The purpose of this part of ISO/IEC 9318 is to facilitate the development and utilization of an intelligent interface which permits the interconnection of multiple peripheral types such as disk, tape, communications, to a controller.
This part of ISO/IEC 9318 does not replace any existing standard, but it does complement other Intelligent Peripheral Interface (IPI) standards (see clause 2).
This part of ISO/IEC 9318 provides a definition of the device-generic portion of a family of standards cailed the Intelligent Peripheral Interface (IPI), a high performance, general-purpose parallel peripheral interface.
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.
〓 accomplish this set of goals, the design of the IPI includes device-specific and device-generic command sets, both utilizing a common physical bus. The device-specific command set provides
- devicc-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;
- logicai 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.
DS/ISO/IEC 9318-4:1991 history
2007DS/ISO/IEC 9318-4:2007 Information technology - Intelligent peripheral interface - Part 4: Device generic command set for magnetic tape drives (IPI-3 tape)
1991DS/ISO/IEC 9318-4:1991 Information processing. Intelligent Peripheral Interface. Device generic command set for magnetic tape drives