Component Availability

Reliability can reasonably be defined for an individual component. Availability depends intrinsically on the service discipline of a system so that a component can not be assigned a measure of availability exclusive of the system in which it operates. To obtain a general formulation the structural details of the system are omitted and the action of the system is represented by the waiting time distribution of the component service queue. Two approaches to the definition of component availability are given. 1) An integro-differential equation definition in terms of the service waiting time distribution. 2) A methodological definition for component availability in terms of the details of a combinatorial queue model.