Beware of early daylight-saving time

Congress lengthened this year’s daylight saving time by four weeks in the name of energy efficiency. The decision is likely to affect numerous computer systems preset to change the hour on the traditional date.

Many people aren’t even aware of the change, which takes effect Mar. 11. Devices such as cell phones should automatically update. But Microsoft cautions that some of its older products—including Windows XP SP1 and Windows NT4—will require manual updates. The company’s Web site provides detailed instructions on how to update various products. As a fallback, Microsoft says customers should double-check meetings scheduled electronically during March and April 2007.