  We motivate and propose a new way of thinking about failure detectors which
allows us to define, quite surprisingly, what it means to solve a distributed
task \emph{wait-free} \emph{using a failure detector}. In our model, the system
is composed of \emph{computation} processes that obtain inputs and are supposed
to output in a finite number of steps and \emph{synchronization} processes that
are subject to failures and can query a failure detector. We assume that, under
the condition that \emph{correct} synchronization processes take sufficiently
many steps, they provide the computation processes with enough \emph{advice} to
solve the given task wait-free: every computation process outputs in a finite
number of its own steps, regardless of the behavior of other computation
processes. Every task can thus be characterized by the \emph{weakest} failure
detector that allows for solving it, and we show that every such failure
detector captures a form of set agreement. We then obtain a complete
classification of tasks, including ones that evaded comprehensible
characterization so far, such as renaming or weak symmetry breaking.
