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The output of the compiler is in Executable and Linkable Format (ELF). We use three types of standard ELF files. Unlinked compiler output files are of type Relocatable. The core containing RTEMS and run-time libraries is of type Executable, i.e., the format for main programs. Modules are stored as Shared Object files, i.e., shared library format. ELF has just the single format for both uses: modules loaded explicitly by the application such as Python extension modules as well as for libraries with one memory image shared among multiple processes. In RTEMS there are no processes and there is only one address space for main memory so the "shared" part of "shared object" is irrelevant; we just want the load-on-demand capability. Some non-ELF platforms such as MacOS X use different file formats for loadable modules and for shared objects so the two are not interchangeable.
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