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.