Slides - Åbo Akademi

Reliability Parameters
MTTF: Mean Time to Failure, i.e., the expected time that a system will
operate before the first failure occurs (often term MTBF – Mean Time
Between Failures – is used for repairable systems)
MTTR: Mean Time to Repair, i.e., the average time taken to repair a
system that has failed
MTTR includes the time taken to detect the failure, locate the fault,
repair and reconfigure the system.
MTTF =
∫ ∞
0
R(t)dt MTTR =
∫ ∞
0
(1 − M(t))dt
Availability of a repairable systems is defined as
MTTF
MTTF + MTTR