There is a natural tension between real-time predictability and fault-tolerance capabilities in computing systems. There is a need for both real-time predictability and fault-tolerance in defense systems; they must timely deliver the required functionality in the face of unexpected environments that deliver unpredictable events. As a result, the efficiency of defense systems is often compromised to allow the recovery from faults to be factored directly into the worst case execution time of operations in order to ensure real-time predictability. The Common Object Request Broker Architecture (CORBA) is a widely adopted, effective infrastructure for defense systems. A specification for a real-time variant of CORBA is supported by a number of commercial and open source products. A specification for a fault-tolerant variant of CORBA has been developed that supports strong consistency between replicas of objects. Unfortunately, neither of these specifications address the concerns of the other, so that a CORBA specification that supports both fault-tolerance and real-time is not available. The CORBA Naming Service provides a tractable and well-understood application of CORBA suitable as a candidate for evaluating the practicality of the techniques identified in research that has been directed toward reconciling the tension between real-time and fault-tolerance.
