NoWait-RPC: extending ONC RPC to a fully compatible message passing system

Locally and functionally distributed applications realized on different system architectures demand a universal, portable and intuitive software utility for interprocess communication. Remote Procedure Calling (RPC) fulfills these requirements but suffers unnecessarily strict synchronization and the danger of deadlocks with complex client/server relations. Using message passing to avoid the inherent problems of RPC, however requires additional knowledge and sometimes a complete structural redesign. This paper presents NoWait-RPC, an extended but fully compatible version of SUN´s Open Network Computing Group´s ONC RPC, which adds message passing capabilities to form an easy to use programming environment for robust system integration. NoWait-RPC was developed to resolve potentially arising deadlocks in an already RPC-based complex application. It is designed to be a plug-and-play substitute for ONC RPC and consists of the library and the extended protocol compiler nwrpcgen. Additionally, applications using the asynchronous (non-blocking) features of NoWait-RPC may experience a major speedup compared to ONC RPC through pipelining calls to different servers. It has successfully been employed in a research programme dealing with the development of autonomous mobile robots