Evolving Dependable Real-Time Systems

Annotation: Describes the Simplex architecture for supporting evolution of real-time systems that use commercial off-the-shelf (COTS) components. Upgrades are supported by grouping a set of analytically redundant components (i.e., that satisfy the same abstract spec) into a subsystem module. Each module contains a safety component that is assumed correct but may be inefficient, a baseline component that acts as the ``leader'' of the replica group, and an optional new component that is evaluated against the other two. Each module also contains a management system that monitors the components for errors (e.g. functional or resource utilization). If the new component behaves correctly according toa user-specified metric, the system replaces the baseline component with the new one. A two-phase protocol is used to atomically switch over a set of distributed components.

BibTeX entry:

@techreport{sha95evolving,
   author = {Lui Sha and Ragunathan Rajkuman and Michael Gagliardi},
   title = {Evolving Dependable Real-Time Systems},
   institution = {CMU},
   number = {CMS/SEI-95-TR-005},
   year = {1995}
}