Although you can perform the conversion process without architecture definitions, their creation can greatly simplify the conversion process as well as support future development needs. Define a set of architecture members first for the code in the topmost group of the hierarchy. These architecture members must reference only members that are present in the topmost group because only those members are visible during the first group conversion.

To determine which architecture members you need, perform the following steps:

1. Determine whether all the build translators can use the default translator options in the language definitions. If they can, you do not need compilation control architecture members.
2. Determine the contents of every load module to be controlled. The IEHLIST utility prints the names of all objects in a load module.
3. Produce a linkage edit control architecture member for every load module, and reference each object (actually compilable source members) with an INCLD statement. Use the INCL statement in place of INCLD to reference compilation control architecture members if they are created above.
4. Produce high-level architecture members as needed to control any non-translatable data or data that is not included in load modules.
5. Produce a high-level architecture member and reference each linkage edit control architecture member and high-level architecture member defined above with an INCL statement.

The high-level architecture member created in Step 5 now defines, through its dependencies, the entire application architecture.

After you create the architecture members for the topmost group, you might need to add modifications in the lower groups of the hierarchy. Members that were added during the development process and were not moved to the topmost group may require additional architecture members. You must introduce architecture modifications in the group requiring the change. This action allows the architecture for the hierarchy to match the members controlled in the hierarchy. See Architecture definition for a description of the process and syntax for defining architecture members.