Glossary A–ZLetter M
MTBF
MTBF is the mean operating time between two failures, determined as a statistical average across a large number of identical devices.
The abbreviation stands for “mean time between failures”. It is stated in hours.
Manufacturers give the MTBF for screens, players, power supplies or storage. The value is usually derived from calculation models for the components used or from accelerated tests, not from years of observation in operation. It helps to compare devices of the same kind and to estimate how many failures per year a large network should expect.
A common misunderstanding is that MTBF is the life expectancy of a single device. A value of many tens of thousands of hours does not mean that every device will run that long; it describes the failure rate in a large population during the period of use. Wear at the end of the lifetime is often not included. Operators should ask how the value was determined and for which temperature it applies, and keep spare devices in proportion to the size of their network.