UWS times

[Walter Landry]

Paul Harrison <paul.harrison at manchester.ac.uk> wrote:
> 
>> On 2016-03 -23, at 08:52, Markus Demleitner <msdemlei at ari.uni-heidelberg.de> wrote:
>> The main reason is: Supporting time zones is a *huge*
>> implementation concern (unless you put serious restrictions over
>> ISO 8601), and given things like daylight savings time, makes the
>> standard susceptible to lawmaking in the greater world.  Also,
>> while explicit time zone notation (e.g., CEST vs. CET) mitigates
>> that particular problem, local times have hours that pass twice
>> (next autumn for us) and ones that don't pass at all (this Sunday
>> morning in much of Europe).
> 
> I am not convinced that it is such a huge implementation issue - the
> libraries for support must surely be in place in most environments
> as ISO 8601 timestamps are pretty widespread. If you restrict
> yourself to the +/- hh:mm timezone designation then there are no
> problems with ambiguity - however I do agree that it all can cause
> confusion if not used properly though.

It is a huge implementation issue if you want to do it correctly.  It
is just that most people do not do it correctly, because that would
require a historian.  I really do not want to worry about Samoa moving
itself back and forth over the international dateline, or whether I am
on Eastern or Western Kiribati.  Even accounting for leap seconds
introduces problems that most people ignore.  For example, it is not
correct to subtract MJD's.

Cheers,
Walter Landry