When Coding Goes Awry

Software bugs can be more than just annoying. They can be expensive, costing companies billions of dollars in repairs, lawsuits and lost sales. These coding errors can also cause physical damage and, in the worst case, fatalities.

As Knight Capital Group Inc., one of the biggest U.S. market makers for stocks, struggles to survive a software bug that triggered a $440 million loss, here's a look at some of the costliest and most dramatic malfunctions over the past 50 years.