Resilient systems keep working, even when there is an error. Well, not any error. That would be a miracle, or simply nonsense! An error generally is an error. If armageddon comes and it is the end of the world as we know it, even resilient systems will not be responsive. For smaller disruptions, however, there may be some cure to make the systems resilient.
There are techniques that may help if only a disk fails, there is a power outage, or there is a programming error. Systems may be replicated, so when one of the instances stops responding, some other instance may take up the task of the failing one and can go on working. Systems prone to errors may be isolated from one another in terms of space or time. When there is an earthquake ...
