THE DESIGN OF THE TAO REAL-TIME OBJECT REQUEST BROKER

Many real-time application domains can benefit from flexible and open distributed architectures, such as those defined by the CORBA specific ation. CORBA is an architecture for distributed object computing being standardized by the OMG. Although CORBA is well-suited for convention al request/response applications, CORBA implementations are not yet su ited for real-time applications due to the lack of key quality of serv ice (QoS) features and performance optimizations. This paper makes thr ee contributions to the design of real-time CORBA systems. First, the paper describes the design of TAO, which is our high-performance, real -time CORBA 2.0-compliant implementation that runs on a range of OS pl atforms with real-time features including VxWorks, Chorus, Solaris 2.x , and Windows NT. Second, it presents TAO's real-time scheduling servi ce that can provide QoS guarantees for deterministic real-time CORBA a pplications. Finally, the paper presents performance measurements that demonstrate the effects of priority inversion and non-determinism in conventional CORBA implementations and how these hazards are avoided i n TAO. (C) 1998 Published by Elsevier Science B.V.