Reliability—A measure of successful operation for a specified interval of time. Reliability, R(t), is defined as “the probability that a system will perform its intended function when required to do so if operated within its specified limits for a specified operating time interval.” The definition
includes five important aspects.
1. The system’s “intended function” must be known.
2. “When the system is required to function” must be judged.
3. “Satisfactory performance” must be determined.
4. The “specified design limits” must be known.
5. An operating time interval is specified.