The result is a glitch reminiscent of the Y2K bug, when cataclysmic crashes were feared if computers interpreted the year 2000 as 1900 and couldn’t reconcile time appearing to move backward. This bug is much less threatening, but it could cause head-scratching episodes when some computers are an hour off. The problem won’t show up only in computers, of course. It will affect plenty of non-networked devices that store the time and automatically adjust for daylight saving, like some digital watches and clocks. But in those instances the result will be a nuisance (adjust the time manually or wait three weeks) rather than something that might throw a wrench in the works. Cameron Haight, a Gartner Inc. analyst who has studied the potential effects of the daylight-saving bug, said it might force transactions occurring within one hour of midnight to be recorded on the wrong day. Computers might serve up erroneous information about multinational teleconference times and physical-world appointments. “Organizations could face significant losses if they are not prepared,” the Information Technology Association of America cautioned this week. Dave Thewlis, who directs CalConnect, a consortium that develops technology standards for calendar and scheduling software, said it is hard to know how widespread the problem will be. For three weeks this March and April, Microsoft Corp. warns that users of its calendar programs “should view any appointments … as suspect until they communicate with all meeting invitees.” Wow, that’s sort of jarring – is something treacherous afoot? Actually, it’s a potential problem in any software that was programmed before a 2005 law decreed that daylight-saving time would start three weeks earlier and end one week later, beginning this year. Congress decided that more early evening daylight would translate into energy savings. Software created earlier is set to automatically advance its timekeeping by one hour on the first Sunday in April, not the second Sunday in March (that’s March 11 this year). That’s because the world is full of computer systems that have particular methods for accounting for time of day. In many, changing the rules around daylight saving is a snap, but in others, it may be more complex. “There’s no rule that says you have to represent time in a certain way if you write a program,” Thewlis said. “How complicated it is to implement the change has to do with the original design, where code is located.” Further confounding matters, there are lots of old computer programs whose original vendors don’t support them anymore, meaning there’s no repair available. Some gadgets, such as VCR clocks, may not have any mechanism to update their software. A common fix is a “patch” that reprograms systems with the updated start and end dates for daylight-saving time. Some of these updates are targeted at specific systems, while others have wider implications – such as one from Sun Microsystems Inc. for older versions of the Java Runtime Environment, which often fuels applications on computers and Web pages. Microsoft planned to send its daylight-saving patch to Windows PCs with the “automatic update” feature Tuesday. Users with automatic updates turned off should download the patch from Microsoft.160Want local news?Sign up for the Localist and stay informed Something went wrong. Please try again.subscribeCongratulations! You’re all set!