[PLUG] Daylight Savings Time

Terry Griffin griffint at pobox.com
Sun Feb 11 19:33:32 UTC 2007


On Sunday 11 February 2007 7:16 am, Rich Shepard wrote:
>    An article in this morning's newspaper reminded me that the switch from
> standard to daylight savings time is 11 March this year rather than the
> first Sunday in April.
>
>    Do current kernel versions accommodate this change?
>
> Rich

The kernel doesn't care about DST, or even what time zone you are in. It
always keeps time in UTC.

It's glibc that takes the UTC time from the kernel and converts it to local
time when some app wants to know the local time. Included with glibc is a
time zone database, usually packaged as tzdata. So as long as you are
up to date with the latest tzdata package for your distro then you should
be okay for March 11.

For older versions of Linux distros that are no longer supported, there are
reports of success installing the tzdata package from a newer version of the
same distro.

For some old distro versions tzdata was not packaged separately but instead
was built in to the main glibc package. Again, there are reports of success
doing a forced installation of a new tzdata package from a newer version of
the same distro over the top of the old glibc.

In some cases simply upgrading tzdata is not enough. You may have to
re-run the system's time-zone selection utility to assure that /etc/localtime
is refreshed from the updated data base.

Terry



More information about the PLUG mailing list