Implementation of zoneinfo (Olson, tz) database in .NET c-sharp csharp

[yoshito_umaoka at us.ibm.com]

Masayoshi.Okutsu at Sun.COM wrote on 06/22/2007 07:31:53 AM:

> On 6/22/2007 4:31 AM, Paul Eggert wrote:
> > Does this mean that the Windows-Tzid table maintained by the
> > CLDR project is incorrect, or that CLDR needs a new table for Vista?
> > If so, we should warn the CLDR folks about the problem.  Please see
> > <http://unicode.org/cldr/data/diff/supplemental/windows_tzid.html>.
> > 
> 
> Some time ago I pointed out that there's no concept of tzid on Windows, 
> and I asked how CLDR got these "Windows-Tzids." But I don't think I got 
> any answer.
> 

These is no concept of tzid on Windows, but at least MS maintains
registry keys under -

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones

My understanding is that CLDR folks assumed these "time-zone strings" as
tzids.

MS defines a sort of tzids called "CodTimeZoneId" for Exchange/Outlook.

http://msdn2.microsoft.com/en-us/library/ms526601.aspx

These are obviously a subset of Windows "Time Zones" registries.

> The Java runtime uses the GetTimeZoneInformation() and "Time Zones" 
> registry values to detect the current Windows time zone and map it to a 
> tz database ID using some complicated method. You may want to check 
> <JRE_HOME>\lib\tzmappings in JRE/JDK 6 for Windows and the runtime code 
> for detecting the current Windows time zone. The source code can be 
> downloaded from http://download.java.net/openjdk/jdk7/.
> 
> Masayoshi

Windows used to support only a pair of DST start/end rules per zone,
but MS finlally implemented a framework for supporting historic
changes since Windows Vista.

http://msdn2.microsoft.com/en-us/library/ms724253.aspx

I do not think this enhancement has any impacts to Java runtime on
Windows although.

Yoshito