You can't just say it's reliable

摘要

'Aman's got to know his limitations." This is one of the more memorable lines delivered by Clint East-wood in the movie Magnum Force, and it possesses great wisdom. But how does this relate to engineering system reliability? What do we mean when we say that a person is reliable? Is it possible to say that a person is reliable all the time or just sometimes, in all circumstances or in just some circumstances? The same questions need to be applied to an engineering system design because reliability cannot be an afterthought. As we become more dependent on complex mechatronic systems, it is not sufficient to understand just how they work; we must also understand how they fail. Fault-tolerant system design, not just fault-tolerant component or subsystem design, has become paramount.