Subject: [Tzdist] Identification of data source in use.

From: Lester Caine <[email-masked]>
Date: Tue, 11 Nov 2014 20:16:17 +0000

While the concept of identifying the dataset being used by an
information has been introduced in 4.1, there is a chicken and egg
situation with regards {/service-prefix,data-prefix}.

Additional to 4.2.1 ...
" Discovery process may require to find a more suitable source of data
if the service found by the default process does not provide a published
source matching that being used by the calendar data being accessed. "

The question is if the calendar data identifies a suitable
'service-prefix', or if only a 'publisher' is required. That there is no
requirement for the tzdist service to provide a single unified tzid
structure dictates that a particular source matching the publisher being
used is essential. This then leads to the still existing race hazard
with 4.2.2.

Additional to 4.2.2 ...
" It may be necessary to access a particular version of initial data
matching that used by the calendar data in order to ensure a matching
set of data is used as the correct starting point. Data may not match
the latest tzdist version if it has not yet been updated itself. "

Pushing 'version' back to later versions of the standard simply make the
service unusable! It is essential to ensure that the correct tz data is
being used with the calendar data and so has to be properly defined in
the first edition.

-- 
Lester Caine - G8HFL
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