Learn in the textbookReliability Metrics
DefinitionMTBF (mean time between failures) is the average length of normal running time from a restart after repair until the next failure.
ExplanationIt is found by dividing the total time the system ran normally during the operating period by the number of failures. A larger value means fewer breakdowns, so it serves as a gauge of the system's reliability (信頼性), meaning how hard it is to break.
AnalogyIt is the average number of days you can ride your bike after fixing a flat before the next flat.
Memory hookRead Between in Mean Time Between Failures as the gap between two stops, that is, the running stretch from the end of one repair to the next stop.