Sažetak
The fault-tolerant system in this paper is based on cold standby actualization and software redundancy. It is a microprocessor modular system. It consists of standard nonredundant modules and specific additional modules. The fault-tolerant control system performs the validation of the active microprocessor unit and the actualization of the spare unit. In the case of the active unit failure the control from the failed active unit is switched to the spare unit. The fault detection is based on watchdog timer, checksums, data duplication etc. The evaluation of the fault- tolerant behavior of this system is performed by a fault injection in to the active unit bus lines performed by the fault injection system. The fault-tolerant system is tested for nonredundant and redundant software. The influence of the watchdog refresh period and the actualization of standby unit period on the number of detected failures on active and standby unit is registered. It was experimentally shown that fault tolerance of the system could be easy increased by using software redundancy and software methods.
