The Chameleon infrastructure for adaptive, software implemented fault tolerance

This paper presents Chameleon, an adaptive software infrastructure for supporting different levels of availability requirements in a heterogeneous networked environment. Chameleon provides dependability through the use of ARMORs-Adaptive, Reconfigurable, and Mobile Objects for Reliability. Three broad classes of ARMORs are defined: Managers, Daemons, and Common ARMORs. Key concepts that support adaptive fault tolerance include the construction of fault tolerance execution strategies from a comprehensive set of ARMORs, the creation of ARMORs from a library of reusable basic building blocks, the dynamic adaptation to changing fault tolerance requirements, and the ability to detect and recover from errors in applications and in ARMORs.