Software-Fault Tolerance

At the beginning of the Delta-4 project, a design assumption was made to the effect that only physical faults were to be taken into account when providing fault-tolerant mechanisms: the possibility of design faults could therefore be neglected. In the subsequent years, recognizing that software design faults are becoming a major source of system service disruption, it was decided to study how to provide the Delta-4 architecture with specific provisions to deal with this kind of faults.