Accessing the local drive space on the machine

The NPS system shared libraries, originally designed to provide shared library support (lib*.so files) for UDXs, provide the same support for AE applications. However, the functionality was extended so that shared libraries can be any type of file, including executable binaries and data files. These files are read and stored in the core database. When a shared library is registered and stored in the database, the user specifies a symbolic name for the library.

As part of registration, AEs can declare dependencies on a shared library, and at query time. NPS ensures that a local copy is available on the host and the SPUs, which means that the library is not on the shared network drive containing the AE export directory tree. Using this approach, it is possible to design AEs written in languages such as C or C++ so that they are self-contained as UDXs. However, this self-contained approach is only practical for applications that require a relatively small number of support files.

Finally, AEs have access to a certain amount of temporary local drive space on the host and SPU. This space is also used by the NPS system database and is a limited resource. Since each installation is different, a specific maximum disk space usage recommendation is impossible, but excessive use of local disk space can impact the performance of the NPS system database. Therefore, "large" temporary files should be placed in the AE export directory tree. Using local disk space such as the temporary space directory, or by using networked disk space like the AE export directory tree, has performance implications on the NPS system.