Switchover software reliability estimate for Paducah Freezer/Sublimer computer systems
TN (United States) Oak Ridge National Lab., Deborah L. Flanagan, USDOE, Washington, DC (United States), J Davis · 1993
K-25 Engineering Division purchased a series of redundant computer systems and developed software for the purpose of providing continuous process monitoring and control for the Freezer/Sublimer equipment in the gaseous diffusion process at the Paducah Gaseous Diffusion Plant. The application software is loaded on two central processing units (CPU) so that in the event of a failure of the primary unit, the processing can switch to the backup unit and continue processing without error. It is the purpose of this document to demonstrate the reliability of this system with respect to its ability to switch properly between redundant CPU. The total reliability estimation problem -- which considers the computer hardware, the operating system software, and the application software -- has been reduced to one that considers only the application software directly involved in the switchover process. Estimates are provided for software reliability and the testing coverage. Software and hardware reliability models and reliability growth models are considered in addition to Bayesian approaches.