Re: [Tzdist] [tz] Timezone in Brazil

Paul Eggert <eggert@cs.ucla.edu> Sun, 11 October 2015 22:24 UTC

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To: Lester Caine <lester@lsces.co.uk>
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From: Paul Eggert <eggert@cs.ucla.edu>
Organization: UCLA Computer Science Department
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Date: Sun, 11 Oct 2015 15:24:40 -0700
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Cc: Time Zone Data Distribution Service <tzdist@ietf.org>
Subject: Re: [Tzdist] [tz] Timezone in Brazil
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>>> tzdb should only be published with a
>>> 1970 start date and anything prior to that is unreliable

>> >No, many tzdata entries before 1970 are quite reliable.  True, tzdata
>> >entries tend to become less reliable the further back one goes in time,
>> >but this is merely a tendency.  For example, the data for England in
>> >1915 is far more reliable than the data for Baja California state in 2015.

> 'MANY' ... but there is data in backzone

Sure, but backzone is published as part of tzdata, and it's easy to use; just 
set a switch in the Makefile.  And regardless of whether backzone is used, 
there's no good reason to require implementations to reject time stamps before 1970.