Re: [PLUG] Daylight Savings Time

[Stephen Gran <steve@lobefin.net>]

On Fri, Feb 02, 2007 at 11:55:17AM -0500, Doug Crompton said:
> On Fri, 2 Feb 2007, Stephen Gran wrote:
> 
> > On Fri, Feb 02, 2007 at 10:01:46AM -0500, Doug Crompton said:
> > > Is there a general Daylight Savings Time patch for Linux? I am running an
> > > older version that I do not get updates for anymore. I suppose this is
> > > handled in the Kernel. Is there a way to at least turn it off?
> >
> > As has been pointed out, this is a glibc, rather than a kernel, issue.
> 
> Ok but this does not answer my question or maybe it does and I do not
> understand... what would you need to change in an existing Linux system to
> support the DST change? Can this be done without recompiling the kernel?

You'll need to update your zoneinfo file (mine is
/usr/share/zoneinfo/Europe/London, yours will probably be
America/NewYork or something).  You can download new zoneinfo data from
here:
ftp://elsie.nci.nih.gov/pub/tzsource*.tar.gz

And you can build new zone files with:

mkdir -p tzgen/{posix,right}
tar -xzf tzsource*.tar.gz
for zone in africa antarctica asia australasia europe northamerica southamerica etcetera factory solar87 solar88 solar89 backward systemv ; do 
  /usr/sbin/zic -d tzgen -L /dev/null -y tzsource/yearistype.sh tzsource/${zone} 
  /usr/sbin/zic -d tzgen/posix -L /dev/null -y tzsource/yearistype.sh tzsource/${zone} 
  /usr/sbin/zic -d tzgen/right -L tzsource/leapseconds -y tzgen/yearistype.sh tzsource/${zone} 
done

The resulting files need to be installed to wherever your distro keeps
zoneinfo files, presumably also /usr/share/zoneinfo .

> > > This is changed to March 11 this year and if I manually change it then it
> > > will change again on the old date. This is a big problem worldwide,
> > > especially in equipment that has it imbedded in firmware.
> >
> > That's probably an argument against using equipment that isn't
> > upgradeable :)
> 
> True but how would anyone know this? So many devices automatically set
> now, TV's VCR's and on and on. Most of these devices have no means of
> firmware upgrade. You basically would not buy much of anything if you
> followed that rule.

I understand it's not fully reasonable.  It was meant as a tongue in
cheek caution as we move forward to the computerized house future, where
we will be stuck with pieces not working if we don't think about these
issues now.
-- 
 --------------------------------------------------------------------------
|  Stephen Gran                  | "I've got some amyls.  We could either  |
|  steve@lobefin.net             | party later or, like, start his heart." |
|  http://www.lobefin.net/~steve | -- "Cheech and Chong's Next Movie"      |
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