The development of a Distributed Information System (DIS) can lead to critical bottlenecks because of the underlying architecture, which is becoming more and more complex. Todays applications are both object-oriented and based on a new type of three-tiered client/server architecture. In this context, the capabilities of a DIS can be drastically reduced if the performances of the system are not sufficient. Recognizing these trends, industry and research are defining standards and technologies for communicating between components of a DIS and for database access mechanisms. The emerging candidates for these middleware technologies include the OMGs CORBA specification and Microsoft's proprietary solution known as DCOM. A key problem with such complex architectures is the performance issue. This paper presents a simulationbased workbench for predicting the performance of applications relying on these architectures. The proposed tool is based on providing end users with mechanisms to ...