Switching Your Linux Systems to the New DST

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.

/zimages/3/28571.gifWill 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.

/zimages/3/28571.gifRead the full story on Linux-Watch: Switching Your Linux Systems to the New DST

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