FedWire, the electronic clearing system that processes transactions among banks and between banks and their regulators, crashed three times in the space of a month in 1987, even though it has elaborate backup. And in 1990, the combination of a power failure on Wall Street and the failure of a water line meant to cool a backup generator knocked FedWire out again. This time, it took nearly a week to restore the system fully, during the course of which tens of billions of dollars were temporarily in the wrong accounts. Similar problems have afflicted all the major interbank payment systems, but never with lasting consequences. (What's $10 billion between friends, after all?)