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 容錯的技術在于采用冗余工具,也就是采用n模塊冗余構造容錯硬件,采用n版本編程或恢復塊方法構造容錯軟件。