Are the terms stable and reliable interchangeable

system-reliabilityterminology

Is there a difference between stability and reliability (at least in software engineering context) or can they be used interchangeably? If not, what would be some examples of reliable but not necessarily stable systems, and vice versa?

Best Answer

Let's say for instance we have an app, it works perfectly, aside from it crashing every 5 minutes, but it's back up instantly without data loss.

That in my mind is reliable, but not stable.

I can rely on it not losing data and working correctly, despite it not being stable.

In fact, the internet is basically that. It's far from stable—connections drop and reappear, packets collide and are lost, and all kinds of other unstable things happen. However, it's pretty amazing how reliable it is given all the instability inherent in it.