[Info-vax] EU will abandon daylight savings time in 2021

[pcoviello at gmail.com]

On Monday, April 1, 2019 at 4:39:36 PM UTC-4, Stephen Hoffman wrote:
> On 2019-04-01 20:08:57 +0000, pcoviello at gmail.com said:
> 
> 
> > On 4/1/2019 10:00 AM, Stephen Hoffman wrote:
> >> 
> >> The Heisei Era is ending, and the Reiwa era commences on 1-May-2019.  
> >> (Whether that's 1-May local time or 1-May UTC, I've not confirmed.)
> >> 
> >> There are changes happening several times a year, and variously more often.
> >> 
> >> It's rare to hear about TZ changes else-planet.  Including among 
> >> customers, when folks are (knowingly or otherwise) running 
> >> planetary-scale apps.
> > 
> > I have to ask why one would not be using NST for the time anyways?  
> > would this not solve this issue?  or did I miss something?
> 
> If you meant NTP there and not NST, then NTP gets you the ~current UTC 
> time; a value for ~now.
> 
> NTP doesn't get you the Timezone (TZ) data and the current Daylight 
> Saving Time (DST) thresholds, and won't help with all but the simplest 
> and most short-term of time-related math.
> 
> NTP won't get you the shift from the Heisei to Reiwa era, for instance.
> 
> Which means you'll have a UTC time value, but you'll not correctly 
> display the local time in the Reiwa era that starts next month.
> 
> What time it is locally depends not only on UTC, but on where you are 
> located, and when you are on the local calendar.
> 
> Those details and display-related details are acquired from the TZ 
> file.  And the TZ file contents changes.  Such as with the Heisei to 
> Reiwa change.
> 
> Which means downloading the TZ definitions
> 
> Either from VSI via a TZ-related patch, or ad-hoc across the installed 
> base.  With the ad-hoc approach common now and the infrequently-issued 
> TZ patches, most sites will ignore the TZ changes until after somebody 
> runs into a problem.  Then various of the folks will either call for 
> support and get a patch or get instructions on a manual change, or both.
> 
> Reading:  https://en.wikipedia.org/wiki/tz_database
> 
> 
> 
> 
> -- 
> Pure Personal Opinion | HoffmanLabs LLC

yes that is what I meant... my fingers didn't type it correctly...

thanks for the explanation.