All mappings are kept in the PMDF mapping file. ¹ Each time a PMDF program begins running, this file is read and loaded into memory. This overhead can be avoided by compiling your PMDF configuration, in which case the contents of the mapping file will be incorporated into the compiled configuration. The disadvantage to this, however, is that it means that the configuration must be recompiled and reinstalled whenever a change is made to the mapping file or to an include file used by the mapping file. See Section 8.1 for details on compiling your configuration.

The mapping file should be world readable. Failure to allow world read access will lead to erratic behavior.