A resynchronization method for real-time supervision

Real-time supervision is one technique used to improve the perceived reliability of software systems. A real-time supervisor observes the inputs and outputs of the system and reports failures that occur. The approach presented in this paper uses the specification of external behavior of the system to detect failures. Failures are reported in real-time. In addition, the approach permits the assessment of the erroneous states of the system. Following a failure, the supervisor makes an assumption of the (system) erroneous state. Consequences of the same fault are not reported repeatedly. The supervisor accommodates the nondeterminism permissible under some specification formalism. The formalism considered in this paper is the CCITT SDL