Terminology

Term	Description	Example
Failure	A component is not following its specifications	Crashing program
Error	Part of the program that can generate a failure.	Bug
Fault	Cause of the error.	Programmer
Failure prevention	Prevent the occurrence of a failure	Not hiring sloppy programmers
Failure tolerance	Built a component that can mask the occurrence of a failure	Each component is developed independently by two programmers
Failure removal	Reduce the presence, number or severity of failures	Firing sloppy programmers
Failure prediction	Estimate the actual presence, future incidence and consequence of failures	Estimate how the HR is hiring the programmers

Models of failure

Types of failure	Description of the server behavior
Crash failure	Stops, but until then it works well
Omission: - on reception - on emission	Does not respond to messages Does not receive new messages Does not send messages
Temporal flaw	Responds out of the specified time window
Failure in response: - in value - on the transition of state	Response is incorrect The response is wrong Deviation from the correct control flux