The CORBA specification defines an Interface Definition Language, IDL, for defining object interfaces. The SOM Compiler compiles standard IDL interface specifications, but it also allows the class implementer to include implementation information that will be used in the implementation bindings for a particular language.
Note: Before IDL, SOM (version 1.0) had its own Object Interface Definition Language (OIDL). SOM classes specified using OIDL must be converted to IDL before they can be used with DSOM. The SOMobjects Developer Toolkit provides a migration tool for this purpose.