Abstract: Compared with the interprocess communication model of message passing, remote procedure call, and shared memory, a shared object model realized on a distributed memory multiprocessor can describe the interaction of processes more naturally and efficiently. It transcends the physical boundaries between the processor nodes by making use of a few global shared objects and presents the system with a transparent distributed processing capability. Hence, the entire system, both hardware and software, can be viewed logically as a single system. This model has been implemented on the globally shared object （GSO） layer of the instrument oriented weak real time distributed operating system （IOWRTDOS）. The shared object communication model is explored and several key issues of implementation are disussed in detail.