Assured Reconfiguration: An Architectural Core For System Dependability

John C. Knight (Univ. of Virginia)

As computing components continue to become less expensive and physically
smaller, the demand continues for their increased use to support enhanced
functionality in embedded safety- critical systems.  If faults in these
components are to be masked, then they have to be replicated leading to
the need for additional power, cooling, shielding and space. These costs
reduce our ability to use more components in any given system as does the
need for ever increasing amounts of software.  The software domain has
struggled to meet these increasing demands while retaining the necessary
level of confidence in its appropriate operation.  This presentation will
introduce a flexible architecture based on distribution of function and
assured reconfiguration that can react to failures in both hardware and
software. Reconfiguration, when its safety properties are assured, can
enhance analysis capabilities for critical safety properties, allow the
use of fail-stop components rather than reliable ones, and reduce
certification costs for much of the system. This presentation outlines an
architecture for assured reconfiguration, the principles of
reconfiguration assurance, and the accompanying cost and safety
arguments.