When Machines Fail…
Failures occur when machines no longer perform as desired or expected
Mechanical failures tend to be localized and effect a single aspect of the system (e.g., when the brakes on a car fail, the engine still works fine)
CONCEPT: Computational failures can be closely coupled – a small failure in one part of the system may have a significant effect elsewhere in the system (e.g. Zero and the USS Yorktown)