  Optimum lifetime of a series (resp. parallel) system with general standby
component(s) always depends on allocation strategy of standby component(s) into
the system. Here, we discuss three different models of one or more standby
compo- nents. In each model, we compare different series (resp. parallel)
systems (which are formed through different allocation strategies of standby
component(s)) with respect to the usual stochastic and the stochastic
precedence orders.
