SDNF Environment

System Architecture

The diagram illustrates the whole SDNF interface system architecture.

Mapping Files

There are two types of mapping files: internal and external mapping files.

Internal mapping files are prepared by the SDNF interface administrator. They tell the interface where on the computer network the external mapping files may be found. The format of internal mapping files is described. Refer to Internal Mapping Files for further information.

External mapping files are files which determine how the interface handles the data for going to the target package, or coming from the source package; for example, the Profile, Profile Orientation, Unicode and Material mapping files. The format of the external mapping files is described. Refer to External Mapping Files for further information.

Overloading Mapping Files

Overloading of mapping files is permitted and may occur. A file that is found in the first folder is overwritten by a file with the same identifying characteristics, though not necessarily with the same filename (refer to Internal Mapping Files for further information), found later in any of the succeeding folders. For example, a project mapping file can overload a company mapping file.

The sequence of environment variables is set to the locations of the internal mapping files. The interface searches all the folders pointed to by these variables and locate all files with the suffix .map in each sub-folder called SDNFMaps. The .map files are imported during system initialization as internal mapping files. The internal mapping files then become the basis for locating the external mapping files.

However, this does not alter the search rules for the external mapping files as based on the content of the identification line in the internal mapping file.

The diagram illustrates how these environment variables may be used to select and overload sets of internal mapping files.

You do not have to use all three defaults variables.

Relationship between Internal and External Mapping Files

For the purposes of this section, the variable SDNFDATA is assumed to have been set up during the system initialization process and points to the folder containing the external mapping files.

The environment variable SDNFDATA should point to a single folder only. The variable may be made to be project specific, so that the internal mapping files may be kept unchanged, but you are able to pick up mapping files from a project-specific location.

Note:
SDNFMAPS is not a variable specifically required by this interface.

You should take care in using environment variables in internal mapping files, as a recursive scan is not performed at this level. In this case the variable must point to only one folder