Switching Your Linux Systems to the New DST

By Steven Vaughan-Nichols  |  Posted 2007-03-06 Print this article Print

Analysis: With the new dates for daylight-saving time, both people and computers will get confused. Here's how to make sure your Linux and Unix systems get it right. (Linux-Watch)

"Spring forward; fall back." Thats the way the saying goes. Some years I get it backward, but I eventually catch on. Ive never had to worry about my PCs getting it wrong before, though. Now, with the recent changes in the DST (daylight-saving time) rules, I do. Fortunately, there are ways to make sure that both my Linux computers and I get the new rules right.
Until now, most of us in the United States would set our clocks forward an hour in April and back an hour in October.
However, in 2005, Congress passed the Energy Policy Act, which amended the Uniform Time Act of 1966. This turned our old, reliable daylight-saving time completely inside-out. The change goes into effect this year. Will the daylight-saving time change be bigger than Y2K? Read more here. From now on, instead of DST starting on the first Sunday in April, it starts on the second Sunday of March. (This year, thats March 11.) Come fall, daylight-saving time will end on the first Sunday in November—Nov. 4, this year—instead of the last Sunday of October. That means one big mess for many pre-2005 programs and operating systems, which have the old April/October DST rules hardwired into them. Now, unlike Windows, Linux and the rest of the Unix operating system family dont have daylight-saving time innately. Instead, they use an entirely different way of telling time. Most Linux systems have two clocks. The hardware clock, aka the "CMOS clock," is present in most x86-based systems. The CMOS, a battery-backed time clock located on the motherboard, runs 24/7. The system clock, on the other hand, starts when you boot up your system. This is the clock used by most internal Linux programs and Linux applications. Read the full story on Linux-Watch: Switching Your Linux Systems to the New DST Check out eWEEK.coms for the latest news, views and analysis on servers, switches and networking protocols for the enterprise and small businesses.
Steven J. Vaughan-Nichols is editor at large for Ziff Davis Enterprise. Prior to becoming a technology journalist, Vaughan-Nichols worked at NASA and the Department of Defense on numerous major technological projects. Since then, he's focused on covering the technology and business issues that make a real difference to the people in the industry.

Submit a Comment

Loading Comments...
Manage your Newsletters: Login   Register My Newsletters

Rocket Fuel