To tolerate faults, the techniques rely on redundant implementations, which are N-modular redundancy for building fault-tolerant hardware and N-version programming or recovery blocks method for building fault-tolerant software. 容错的技术在于采用冗余工具,也就是采用N模块冗余构造容错硬件,采用N版本编程或恢复块方法构造容错软件。