In a critical application, having two or more of an important resource improves reliability. If one resource fails, the other is there to take over. This is helpful in power supplies, airplanes, and high-end servers. See airplane rule.

• ATM Machine
• PIN Number
• POST Test
• AC Current
• RF Frequency
• NT Technology
• HIV Virus
• EMP Pulse
• GUI Interface
• LCD Display
• ABS System

Re*dun"dance (r?*d?n"dans), Re*dun"dan*cy (-dan*s?), n. [L. redundantia: cf. F. redondance.]

1.

The quality or state of being redundant; superfluity; superabundance; excess.

2.

That which is redundant or in excess; anything superfluous or superabundant.

Labor . . . throws off redundacies. Addison.

3. Law

Surplusage inserted in a pleading which may be rejected by the court without impairing the validity of what remains.

© Webster 1913.