A program module is composed of all input object modules and program modules processed by the binder or linkage editor. The resultant control dictionaries are collections of all the control dictionaries in the input modules. For load modules, the control dictionaries are merged into a single composite external symbol dictionary (CESD) and a single relocation dictionary (RLD). For program objects, the control dictionaries are retained individually. Figure 1 shows how multiple input modules are combined into a single program module.

The output module also contains the text from each input module. If the output is a load module, it also contains an end-of-module indicator.

Figure 1. A program object produced by the binder

As the binder processes object and program modules, it assigns relative virtual storage addresses to control sections and resolves references between control sections.