We revisit synthesis of live controllers for event-based operational
models. Our technique conforms to the foundational requirements
engineering World/Machine model, makes explicit the assumptions on
the environment behaviour and distinguishes between controlled and
monitored actions. We remove one aspect of an idealized problem domain
by allowing to integrate failures of controller actions in the
environment model. Classical treatment of failures through strong
fairness leads to a very high computational complexity and may be
insufficient for many interesting cases. We identify a realistic
stronger fairness condition on the behaviour of failures.
Furthermore, the resulting controllers exhibit the only possible
behavior in face of the given topology of failures: they keep
retrying and never give up. We then identify some well-structure
conditions on the environment that ensure that the resulting
controller will be eager to satisfy its goals. Furthermore, for
environments that satisfy these conditions and have an underlying
probabilistic behaviour, the measure of traces that satisfy our
fairness condition is 1, giving further evidence to the usefulness
of this condition.