64-bit work

[Robbin Kawabata]

> From: "Olson, Arthur David (NIH/NCI)" <olsona at dc37a.nci.nih.gov>
> To: "Tz (tz at elsie.nci.nih.gov)" <tz at lecserver.nci.nih.gov>
> Subject: 64-bit work
> Date: Mon, 23 May 2005 10:36:03 -0400
> 
> Since the 5-byte (rather than 8-byte) extension to the time zone binary data
> file format went over with an overwhelming thud, my current thinking is to
> stick revert to the 8-byte approach.
> 
> The name of the game would be to produce binary files with:
>       1. data with 32-bit time values through 2037 (for use by old
> systems)
>       2. data with 64-bit time values for "historic" years

Can you describe what 2. is?  Is it 400 years of times below the 
year of the earliest rule?  If so, could the algorithm approach be 
used for the early past too?

>       3. a newline enclosed, POSIX-conforming
> TZ-environment-variable-style string
>          telling what to do in years beyond those covered by 2 above.
>
> There are a few places (Cairo, Godthab, Chile) that can't be represented by
> POSIX-conforming strings; for these we'd punt to the "write 400 years worth
> of data and work modulo 400" approach (leaving off the trailing TZ string).

I'm not sure what the problem is with those timezones.  Can you explain?

Robbin