Dynamic configuration management in reliable distributed real-time information systems

A new architecture for large-scale information systems is presented. The original aspects of the architecture are mainly: (1) the time-triggered, message-triggered object (TMO) structuring of the middleware and the application software of distributed real-time information systems; and (2) the dynamic configuration management subsystem (DCMS), based on the supervisor-based network surveillance (SNS) scheme. The positive impacts of this TMO structuring on maintainability and service interruption bounds are first discussed, with distributed replicated information service systems and other systems as examples. The main discussion is on the DCMS architecture. As a component of the DCMS, the network surveillance (NS) subsystem enables fast learning, by each interested fault-free node in the system, of the faults or repair completion events occurring in other parts of the system. Currently, concrete real-time NS schemes that are effective in distributed systems based on point-to-point network architectures are scarce. The SNS scheme presented in this paper is a semi-centralized real-time NS scheme which is effective in a variety of point-to-point networks. This scheme is highly scalable. An efficient implementation model for the SNS scheme is presented that can be easily adapted to various commercial operating system kernels. This paper also presents a formal analysis of the SNS scheme, on the basis of the implementation model, to obtain its strongly competitive tight bounds on the fault detection latency. Finally, some DCMS implementation issues are discussed that remain to be addressed in future research