On January 28, a day of calm seas off the California coast, computer scientist Jim Gray left San Francisco on his 40-foot yacht Tenacious and made for the Farallon Islands, 43 kilometers beyond the Golden Gate Bridge, where he planned to scatter the ashes of his recently deceased mother. He failed to return that evening.

For the next four days, the U.S. Coast Guard searched the ocean around the Farallons but found no trace of him. Gray's friends and colleagues, however, refused to give up. A technical fellow at Microsoft and a pioneer in the development of database systems and transaction processing, Gray, 63, was one of the most beloved figures in the computer science community. Executives at Amazon, Sun, Oracle, Google, Microsoft, and other companies organized an intense private search, even enlisting a plane owned by NASA--a close cousin of the U-2 spy plane--and a satellite operated by mapping company DigitalGlobe to collect thousands of new images of the areas to which Tenacious might have drifted.