The goal of this paper is to provide an architectural analysis of the existing distributed object oriented platforms. Based on a relatively small number of design patterns, our analysis aims at a unified view of the platforms. We achieve this by articulating a series of key issues to be addressed in analyzing a particular platform. This approach is systematically applied to the CORBA, Java RMI, and COM/DCOM platforms. Key words: CORBA Java RMI COM/DCOM Distributed Computing Distributed object Design patterns Software architecture