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Effective fault-handling in emerging complex distributed applications requires the ability to dynamically adapt resource allocation and faulttolerance policies in response to possible changes in environment, application requirements, and available resources. This paper reports an effort on design and implementation of an adaptive fault-tolerance middleware (AFTM) using a CORBA-compliant object request broker resting on the Solaris open system platform. The paper also briefly discusses the essential capabilities of AFTM, the overall system architecture, and its design decisions.

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Middleware implementation of various critical services required by large-scale and complex real-time applications on top of COTS operating system is currently an approach of growing interests. Its main goal is to enable significant reduction in the complexity of application system design and implementation by separating the concerns of the application designer for the application functionality from the concerns for application-independent system issues.This paper presents the middleware architecture named the Realtime Object-oriented Adaptive Fault Tolerance Support (ROAFTS) and a prototype implementation ROAFTS/Solaris realized on top of both a COTS operating systems, Solaris, and a COTS CORBAcomplaint ORB, Orbix. ROAFTS supports distributed real-time applications, each structured as a network of Time-triggered Message-triggered Objects (TMO's), and the TMO is a major extension of a conventional object for use in hard real-time applications.The major components of ROAFTS include a TMO support manager for supporting the execution of TMO's, a generic fault tolerance server, and a network surveillance manager (NSM) which provides the generic fault tolerance server with fast fault detection notices. The generic fault tolerance server and the NSM themselves have been structured as TMO's. A discussion on an effective use of CORBA standards for moderate-precision real-time applications to run on COTS operating systems is also presented.

Effective fault-handling in emerging complex distributed applications requires the ability to dynamically adapt resource allocation and faulttolerance policies in response to possible changes in environment, application requirements, and available resources. This paper reports an effort on design and implementation of an adaptive fault-tolerance middleware (AFTM) using a CORBA-compliant object request broker resting on the Solaris open system platform. The paper also briefly discusses the essential capabilities of AFTM, the overall system architecture, and its design decisions.