Whenever I hear people describe a complex chain of events only to conclude that there was a single root cause, I'm reminded of the old proverb: >For want of a

Whenever I hear people describe a complex chain of events only to conclude that there was a single root cause, I'm reminded of the old proverb: >For want of a nail the shoe was lost. >For want of a shoe the horse was lost. >For want of a horse the rider was lost. >For want of a rider the message was lost. >For want of a message the battle was lost. >For want of a battle the kingdom was lost. >And all for the want of a horseshoe nail. The moral of the proverb is: it is important to ensure that critical systems have redundancy built in.