High Availability Fault Tolerant Architectures Implemented into FPGAs

In the paper, the methodology of fault tolerant systems design based on field programmable gate array are presented. The architectures are based both on duplex and triple modula redundancy systems to which fault detection capabilities are added, the use of on-line checkers for this purpose is demonstrated. It is described how reliability and availability parameters in triple modula redundancy and duplex structures with checkers can be increased. To demonstrate this, analytical calculations based on Markov reliability model are used. It is also shown how the availability parameters can be affected by the operating environment into which the fault tolerant system is implemented. The principles of generating sequence of fault tolerant architectures with different level of diagnostic are presented.