Architecture of ROAFTS/Solaris: a Solaris-based middleware for real-time object-oriented adaptive fault tolerance support

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 application system design separating the concerns of the application designer for the application functionality from the concerns for application independent system issues. The paper presents the middleware architecture named the Real-time 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 CORBA complaint ORB, Orbix. ROAFTS supports distributed real time applications, each structured as a network of Time-triggered Message-triggered Objects (TMOs), 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.