Larch/CORBA: Specifying the Behavior of CORBA-IDL Interfaces Gowri Sankar Sivaprasad The Common Object Request Broker Architecture (CORBA) provides mechanisms for developing heterogeneous, interoperable distributed object systems. In CORBA, the interfaces of objects are specified using the Interface Definition Language (IDL). However, clients and object implementors also need information on the behavior of such objects. Larch/CORBA extends IDL to formally specify the behavior of objects. The language provides mechanisms to specify the concurrency that is inherent in distributed systems. Our goal is to design a language that is usable directly by system designers and programmers. A notable feature of Larch/CORBA is its focus on data rather than on objects in specifying concurrency. It also provides a general mechanism for specifying synchronization. This report presents a preliminary design of Larch/CORBA and a suite of example specifications.