Reliability of information systems with monorank structure

There is considered the problem of defining the indices of the reliability of information systems with a monorank structure with continuous or periodic service. For the service variants under consideration there are made up equations with the assumption that the time of the faultless operation and the time of restoration are distributed in accordance with the exponential law. For a system with a continuous restoration there are determined the recurrent formulae for the definition of the probabilities of states, but for a system with a nonperiodic service — the optimal variants of its functioning.