Americans turn their clocks forward three weeks early this year, raising the specter of glitches for global business, travel and other functions in a scenario raising comparisons to the "Y2K" bug.
Daylight savings time begins the night of March 11-12 for the first time, instead of the first weekend of April, as has been customary.

The change was mandated by the Energy Policy Act of 2005, and is aimed at reducing needs for lighting and other energy costs. The clock change will be the second Sunday in March instead of the first Sunday in April, and end on the first Sunday in November instead of the last Sunday of October.

For some, the early shift may be a mere inconvenience of manually resetting clocks, older computers or video cassette recorders.

But it also poses problems for global airline schedules and a host of computerized functions that require software updates.

Cash withdrawals or credit card payments might be recorded at the wrong time. Stock trades might not be executed at the right time, and airline flight schedules may be affected if foreign carriers fail to update their systems.

Some analysts say the technology updates are reminiscent of those required for the "Year 2000 bug," which required updates or replacement of older computer systems. But unlike the Y2K situation, which garnered widespread attention, many business are ill-prepared, say analysts.

"I should have thought of this earlier," said Deborah Hale, a specialist at the SANS Internet Storm Center, a computer research group.
Hale said some people are verifying their computers, but questioned whether a host of other devices like cell phones, fax machines and computer routers would receive attention.

"How many of them have the code imbedded to change to DST on the first Sunday of April and the last Sunday in October? This is just the tip of the iceberg."

"It doesn't have to be Y2K to spell trouble for companies and governments in American and around the world," said Phil Bond, president of the Information Technology Association of America, a trade group.

"Organizations could face significant losses if they are not prepared. With less than 30 days to go, time is short."

Microsoft said PC users with Windows Vista or the latest Windows XP updates need not take any action. But it posted instructions for updating computers for those with older versions of the operating system, and noted that other electronic devices might need to be manually changed.

"With so little time available to complete the work, it is inevitable that most organizations will experience a glitch or two," said Will Cappelli of the research firm Gartner Inc.

"So at the very least organizations should run a communications program for all staff well in advance of the change and support-service managers should ensure that they are fully staffed on March 11 and 12."

Between March 11 and March 25, there will be a four-hour time difference between London and New York, instead of the normal five-hour gap, and a five-hour difference between Frankfurt, Paris, Madrid or Milan and New York instead of six hours.

"This is a minor problem compared to the big code changes required in the recent past for issues like Y2K or the euro conversion," Capelli said.

"However, significant business damage and liabilities could occur from applications performing their processing at the incorrect time if organizations do nothing."

Mike Dillon, chief technology officer at Quest Technology in California, said some companies will face glitches.

"Not everyone is scheduling enough time to patch all their systems," he said.

"I would be surprised if everyone got the work done," he added, predicting "a mad scramble at the end to get systems up to date.