Intended Use for Architected Interfaces

Hewlett-Packard provides two layers of programmatic access into the MPE/iX operating system, allowing software suppliers to select the layer that best meets their needs:

In the past, although information has been available through intrinsics, software suppliers have used privileged mode to meet performance needs, risking data integrity and system reliability problems possible with the use of privileged mode.

This concern for performance is addressed in the AIF design, which increases performance while minimizing error checking. AIFs are faster and more functional than intrinsics, while providing a higher degree of data integrity and system reliability than privileged mode access.

	NOTE: Architected Interface Facility products provide supported AIFs without the commitment to backward compatibility as with system intrinsics.

For example, many MPE/iX intrinsics were included just to ensure backward compatibility with MPE V. New MPE/iX intrinsics provide the same backward compatibility over the life of MPE/iX. On the other hand, AIFs may change over the life of MPE/iX to reflect changes to system internals. AIF design will be consistent over time, but data returned or the functions provided will change as underlying operating system data structures and functionality change.

	CAUTION: Any use of privileged mode should be carefully considered because the normal checks and limitations that apply to standard users are bypassed in privileged mode. A privileged mode program can destroy file integrity and the MPE/iX operating system software. Hewlett-Packard will investigate and attempt to resolve problems resulting from the use of privileged mode code. This service, which is not provided under the standard service contract, is available on a time and materials billing basis. Hewlett-Packard will not support, correct, or attend to any modification of the MPE/iX operating system.