Increasing Navy use of embedded computer systems results in stringent requirements for real-time performance, reliability, and cost. Computer systems are critical embedded components of Naval warfare systems. The demands on embedded computer systems are increasing in terms of information processing and storage/retrieval. The designer must analyze results across many dimensions to identify critical design components and initiate design changes that meet numerous requirements simultaneously. These mission critical distributed computer systems are too complex to engineer without automated support. Currently available stand-alone support tools provide no help for managing complex design tradeoffs between performance, reliability, and cost. Previous research results can provide a basis for developing an expert system for extensible, multi-measure design evaluation of real-time distributed systems. The Phase l effort will determine the feasibility of developing an expert system/ performance modeling tool to provide extensible support for engineering complex real-time, distributed systems. The proposed tool will be of immediate use by the Navy. It will result in lower cost, greater reliability, and higher performance while reducing developmental and operational risks. Because the expert system will be extensible, it will be applicable to a wide range of Naval systems.