A FailureMode is an actoin or state used when software or hardware detects a failure. Failure modes include:

• KernelPanics, which occur in the linux kernel when it detects an internal error and cannot go on. A KernelPanic results in the machine rebooting or freezing.
• CoreDumping and process termination are failure modes which occur when a POSIX process performs an illegal operation. They are handled by the underlying Kernel.

Ideally failure modes should be safe, that is render the system into such a state that no damage happens. In most desktop PCs this is relatively easy, but some computer systems, such as AirTrafficControl systems, lack safe failure modes.