The capability of hardware or software to perform as the user expects and to do so consistently throughout a specified system lifetime, without failures or erratic behavior. Reliability may be compromised by a failure (the system no longer meets its design specifications), an error (an inherent flaw in the system that produces incorrect results), a fault (erratic or erroneous behavior caused by a system state that designers failed to anticipate), or human error. Reliability and safety must be distinguished; a reliable system is still unsafe if the system’s use involves a hazard (a condition in which a mishap could occur) and no provisions are made in the event of its failure, however unlikely. Reliability should also be distinguished from availability. In Bhopal, India, chemical plant engineers disabled plant safety systems to increase the availability of processing systems; the result was a catastrophic loss of life. See error.
Reliability
