MTTF & MTBF has been searched with Google, and he wrote it.
MTTF (Mean Time to Failure) Average failure waiting time
If the N identical system (hardware or software) is tested, their failure time
They are T1, T2, ..., TN, and MTTF define as
N mttf = 1 / n σ Ti i = 1
MTBF (Mean Time Between Failures) Average Troubleshooting Time
There is also a mean time of time separation.
MTBF refers to the average time between two successive failures (failures). Usually
When N is large, the average time between the system nth and Nth 1 fault (failure).
