To fail in such a way that no loss or dangerous condition results. When the term is applied to a system, it implies the existence of backup facilities that can assume the full functions of certain primary facilities in event of their failure.

• 保证系统不致产生损毁或危险状态的一种安全措施。采用失效保护的系统，当系统的某些主要部分出现故障时，能使后备功能立即投入使用，承担起这些主要部分的全部作用。