Towards predictable CORBA-based Web-services

The Common Object Request Broker Architecture (CORBA) is a widely-accepted, standardized open system integration framework based on distributed object technologies, which has been successfully used for implementation of open Web services. CORBA is focused on facilitating general computing environments and does not explicitly address quality-of-service parameters neither for its communication links nor its endsystems. However efforts like the Real-Time CORBA Special Interest Group (SIG) at OMG and the "pluggable protocols" proposal will ultimately lead to support of quality-of-service properties for CORBA communication links. We concentrate on architectural approaches for fault-tolerant, highly available endsystems. We present the Observer approach for implementation of reliable CORBA clients. Consensus protocols based on the Composite Objects technique is our solution for constructing CORBA servers with high predictability regarding timely and reliable method execution. Our middleware uses commercial off-the-shelf (COTS) technology and aims at conversion of legacy applications into reliable Web-services. We present Java-based Web-interfaces to the Balancing Robots soft real-time simulation. Also, we demonstrate a fault-tolerant version of the Netscape Navigator based on our Observer technique.