
Concepts Related to System Availability ◾ 21
When the broken-down unit is repaired, all units enter the working state at once
and the system does the same accordingly.
Parallel system refers to a system consisting of n different units and one repair
worker. e system can work when all those n units can work or at least two units
can work. e system only enters failure sate when all the n units break down. Once
one unit breaks down, the repair worker shall immediately repair it. e broken-
down unit enters a working state right after it is repaired. If one broken-down unit
is not repaired and another one breaks down, then the second one enters ...