[ntp:questions] Re: Time changed in Paraguay, how do I fix my clock?

David Woolley david at djhwome.demon.co.uk
Mon Mar 14 21:36:13 UTC 2005

In article <4235afd5$1$28977$e4fe514c at news.xs4all.nl>,
Maarten Wiltink <maarten at kittensandcats.net> wrote:

> a time zone editor in the Windows 95 Kernel Toys. On Unix, /etc/localtime
> is a copy of or a soft link to a file under /usr/share/zoneinfo and while

That is only true of a subset of systems using the Olsen timezones package.
It's not, for example, true of SCO Unix.  For many Unices it is purely
a system administrator job to maintain the timezone rules, typically as
a specially formatted TZ variable setting (I believe glibc supports these
as well as well as the Olsen package).  There may still be early Unices
around which have the old US daylight saving rules hard coded and only
support whole hour timezones.

> I don't know the file format, it's bound to be described somewhere. You
> could also ask the people who maintain those files for an update, or the
> president who broke the old one.

One doesn't update the binary files, one updates the text version (which
tends to be part of the source distribution for open source systems and
may have to be downloaded independently of the vendor for proprietary

The latest Olsen Paraguay rules (at
ftp://elsie.nci.nih.gov/pub/tzdata2005g.tar.gz) are:

  # From Jesper Norgaard Welen (2005-01-02):
  # There are several sources that claim that Paraguay made
  # a timezone rule change in autumn 2004.
  # From Steffen Thorsen (2005-01-05):
  # Decree 1,867 (2004-03-05) <http://www.labor.com.py/noticias.asp?id=27>
  Rule    Para    2004    max     -       Oct     Sun>=15 0:00    1:00    S
  Rule    Para    2005    max     -       Mar     Sun>=8  0:00    0       -
The file is actively maintained and, in fact, changed today.  It looks
as though this change went in around January 5th.  The full file includes
all the known back history, allowing Unix  and Unix-like systems to 
correctly report historic file times.

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