The adaptable distributed recovery block scheme and a modular implementation model

The purpose of adaptive fault-tolerance (AFT) is to meet the dynamically and widely changing fault-tolerance requirement by efficiently and adaptively utilizing a limited and dynamically changing amount of available redundant processing resources. In this paper we present one concrete AFT scheme, named the adaptable distributed recovery block (ADRB) scheme, which is an extension of the Distributed Recovery Block (DRB) scheme for reliable execution of real-time applications with the tolerance of both hardware and software faults in distributed/parallel computer systems. An ADRB station dynamically switches its operating mode in response to significant changes in the resource and application modes. Different operating modes have different resource requirements and yield different fault tolerance capabilities. A modular implementation model for the ADRB scheme is also presented. An efficient execution support mechanism for the ADRB scheme has been implemented as a part of a timeliness-guaranteed kernel developed at the University of California, Irvine.