Amendment 2: Date range for the 1904 date base?

[rjelliffe at allette.com.au]

> Chris,
>
> Remember that in the proposed date profiling changes, the lower limit of
> the date range would be year 1, no year zero or negative years would be
> allowed.

Again, numbers like 2,958,465.9999884 surely have some basis in their
representation in data structures. E.g.
 struct date {
    signed short days;
    short seconds;
}
or whatever. I think it would be much better for this information to be
explicit, even if it just a compatibility note. What is it?

Cheers
Rick Jelliffe


> Date base definitions from IS 29500 (18.17.4.1):
>
> Three different bases can be used for converting dates into serial values:
> * In the 1900 date base system, the lower limit is January 1, -9999
> 00:00:00, which has serial value -
> 4346018. The upper-limit is December 31, 9999, 23:59:59, which has serial
> value 2,958,465.9999884.
> The base date for this date base system is December 30, 1899, which has a
> serial value of 0.
> * In the 1900 backward compatibility date-base system, the lower limit is
> January 1, 1900, 00:00:00, which
> has serial value 1. The upper limit is December 31, 9999, 23:59:59, which
> has serial value
> 2,958,465.9999884. The base date for this date base system is December 31,
> 1899, which has a serial
> value of 0.
> * In the 1904 backward compatibility date-base system, the lower limit is
> January 1, 1904, 00:00:00, which
> has serial value 0. The upper limit is December 31, 9999, 23:59:59, which
> has serial value
> 2,957,003.9999884. The base date for this date base system is January 1,
> 1904, which has a serial value
> of 0.
>