[tz] Deprecating POSIX Zones to Links?

[Yoshito Umaoka]

I’m wondering if these legacy zones can be moved from northamerica / europe files to backward.

I’m not sure about the background why ECMA folks require these zones supported in their spec, but one of the reasons why time zone database adopters try to support these legacy zones (EST5EDT, CST6CDT…) as same as modern/practical zones (America/New_York, America/Chicago..) is that these zones are in same zoneinfo files.

My understanding is that these zones are included in the time zone database for backward compatibility purpose. I don’t know if there are any time zone database users still requiring these artificial zones. If these are moved to “backward” file, it would be clear for time zone database consumers that these are there for backward compatibility reasons.

I also understand what Justin is willing to achieve. Historical zone offsets since 1970 are identical between EST5EDT and America/New_York. For some time zone adaptors, it would be nice if they can reduce number of unique zones. But, there might be still some time zone database users who want EST5EDT defined separately from America/New_York.

For these reasons, I propose -

1) Move these legacy zones to “backzone” with keeping the current definition.
2) Also add them in “backward” file, but change EST5EDT and others as “Link” of modern zone sharing same historic offsets.


Yoshito Umaoka
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