Template:Bs system point reliability

Point Reliability
Point Reliability shows the system’s point reliability over time. The point reliability is the probability that the system has not failed by time t. This is similar to point availability with the major exception that it looks only at the probability that the system did not have a single failure. Other (non-failure) downing events are ignored. It is very important to note that this value is not always the same as the reliability computed using the analytical methods, depending on the redundancy present. The reason that it may differ is best explained by the following scenario:

Assume two units in parallel. The analytical system reliability, which does not account for repairs, is the probability that both units fail. In this case, when one unit goes down, it does not get repaired and the system fails after the second unit fails. In the case of repairs, however, it is possible for one of the two units to fail and get repaired before the second unit fails. Thus, when the second unit fails, the system will still be up due to the fact that the first unit was repaired.

Both Point A & R shows the system’s point availability over time and the system’s point reliability over time on the same plot.