The present paper deals with a reliability model of a two unit cold
standby system that exposed to two types of failures. In each unit
there are hardware and software componentes work together and
fail independently. there is a single server who visits the system
immediately when required. The server inspects the unit in case
of software failure and decides either to repair or replace it. The
h/w components undergo for repair at their failure and are replaced
by new one in case of arriving to maximum repair time. All time
distributions are considered to be exponential. Various measures
of reliability of the system are obtained using regenerative point
technique. Finally simulation study is done to illustrate the results.