[tz] [PATCH 2/3] Replace some zones with links when that doesn't lose non-LMT info.

Lester Caine lester at lsces.co.uk
Tue Sep 3 20:10:39 UTC 2013


Meno Hochschild wrote:
>     Lester Caine wrote: >/can we at least agree that the quality of the material
>     is heading in the right direction? / Yes, that's the idea.
>
>
> While I personally have no problem with tidy-up of obviously wrong data and also
> agree that correction of mistakes is more important than stability (which has
> never been absolutely pretended), I think end-users of tzdb should get a better
> opportunity to estimate how reliable the data are and how much trust they can
> put in their time zone calculations.
>
> Offsets in LMT-lines can easily be qualified as UNKNOWN. For the proposed date
> of 1970 as general separation point between UNSAFE and (apparently) RELIABLE I
> am not so sure. Would it not be helpful for end-users if there is an additional
> year-type attribute per zone which tells the users since when the data can be
> confirmed with high probability of correctness? Would require about 400+
> attributes (ok, 1970 as default). I am sure for example in UK or in Germany the
> data are correct even a pretty while before 1970. Flexibility would be a good
> thing, isn't it? External APIs could support the users with this extra quality
> information per offset and make them better aware that historical tz data are
> not set in stone.
>
> Just giving a thought...

1970 as a nominal date is more of a hindrance than a help ;)
Totally agree that there should be some flag if the validity of an entry does 
not have a documented basis. As I said already UK/Isle of Man are good back to 
1880's and I see no reason we should not have the same confidence with most of 
Europe? So some indication of what IS 'woolly' would be of more help in then 
addressing the holes.

-- 
Lester Caine - G8HFL
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