[tz] [PATCH 0/2] Follow Australian common usage and update CST/CST to CST/CDT and EST/EST to EST/EDT etc [SEC=UNCLASSIFIED]

[Timothy Arceri]

On 2013-04-11 12:53, Dennis Ferguson wrote:
> Is there a reason to change the historical TZ database abbreviations
> rather than just making a change which is applied going forward?

David makes the point very well here. As I stated in my email there was never any references of the current abbreviations use given when it was implemented and it has been a mistake from the beginning. As David says "I don't think its the responsibility of tz to report what tz did in the past - but to represent what was in common use in the past." 
This is also set out in the 'Procedures for Maintaining the Time Zone Database' document. "To be clear, the TZ Coordinator SHALL NOT set time zone policy for a region but use judgment and whatever available sources exist to assess what the average person on street would think the time actually is, or in case of historical corrections, was."

>  You can't really fix what has already happened, and attempting to pretend that it didn't happen that way just seems to increase the ambiguities that people with a need to interpret old timestamps produced with old 
> versions of the TZ database need to deal with while having no offsetting advantages that I can see.

There is no attempt to pretend that this didn't happen. Just fixing a past mistake. Your issue seems to be only with old timestamps however you fail to see that most high quality website (and the large amount of non website documents) over the last 20+ years have been fixing their pages to use the commonly used EDT etc anyway, these pages are usually much more important such as weather records, government reports etc than somebody’s first website they created in 1996. I think the benefit of fixing a past mistake finally removing any ambiguities out ways the few instances were the Eastern Summer Time abbreviation has been use wrongly in the past. Maybe it would be a good idea though to document exactly what has changed and from what date in the comments section of the datafile for future reference.   

Tim
________________________________________
From: tz-bounces at iana.org [tz-bounces at iana.org] On Behalf Of David Patte ₯ [dpatte at relativedata.com]
Sent: Friday, 12 April 2013 3:33 AM
To: tz at iana.org
Subject: Re: [tz] [PATCH 0/2] Follow Australian common usage and update CST/CST to CST/CDT and EST/EST to EST/EDT etc [SEC=UNCLASSIFIED]

There is a use case to change them back to the introduction of  daylight
saving time if it is judged that that that has been the preferred
abbreviation since that time.

For the same reasons as going forward, a tool (such as a calendar) which
reports past daylight saving time events remains ambigious for past
dates if the abbreviations are not put into the database retroactively.
I don't think its the responsibility of tz to report what tz did in the
past - but to represent what was in common use in the past.


On 2013-04-11 12:53, Dennis Ferguson wrote:
> Is there a reason to change the historical TZ database abbreviations
> rather than just making a change which is applied going forward?

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