As the end of the twentieth century and the end of the second millennium approached, governments, corporations, and people around the world worried that their computer systems would stop working. The reason for this concern lay in conditions created in the early days of computing. To save memory and computing power, early programmers used a two-digit date system, which listed the year 2000 (Y2K) as "00." This meant that when the date clicked over from 1999 to 2000, many of the world's computers would think it was 1900. It was feared that many would stop working altogether because of internal conflicts. On planes, at military installations, and in medical life-support systems, the consequences could be disastrous.

In the closing years of the twentieth century, countries spent billions of dollars correcting computer systems to make them "Y2K compliant." Banks, social security systems, and food distribution centers were all...