On 2022-10-06 14:25, Brooks Harris via tz wrote:
On 2022-10-06 4:07 PM, Paul Eggert wrote:
Yes, as I understand it Microsoft Windows 8.1 and later has data derived from tzdb in its Windows Runtime / Universal Windows Platform classes.
Uses MS port of tz code/data for UWP Store apps.
The time zone information resides in the Windows Registry, at HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones
Used by native MS Windows libraries and apps: MS do their own thing here. It would not be too hard to convert from tz to MS reg data to provide correct times in earlier years. Windows dynamic time zones may have been added to support the EU 2006 and/or US 2007 changes, and new data is now added for other zones. The earliest dynamic zone I can find is for Cuba 2003. Base data is static current e.g. Cuba Standard Time Display (REG_SZ) = "(UTC-05:00) Havana" Std (REG_SZ) = "Cuba Standard Time" Dlt (REG_SZ) = "Cuba Summer Time" MUI_Display (REG_SZ) = "@tzres.dll,-2430" MUI_Dlt (REG_SZ) = "@tzres.dll,-2431" MUI_Std (REG_SZ) = "@tzres.dll,-2432" TZI (REG_BINARY) = 2c 01 00 00 00 00 00 00 but some zones also support 'Dynamic DST' e.g. FirstEntry (REG_DWORD) = 0x000007d3 (2003) LastEntry (REG_DWORD) = 0x000007dd (2013) 2003 (REG_BINARY) = 2c 01 00 00 00 00 00 00 2004 (REG_BINARY) = 2c 01 00 00 00 00 00 00 2005 (REG_BINARY) = f0 00 00 00 00 00 00 00 2006 (REG_BINARY) = 2c 01 00 00 00 00 00 00 2007 (REG_BINARY) = 2c 01 00 00 00 00 00 00 2008 (REG_BINARY) = 2c 01 00 00 00 00 00 00 2009 (REG_BINARY) = 2c 01 00 00 00 00 00 00 2010 (REG_BINARY) = 2c 01 00 00 00 00 00 00 2011 (REG_BINARY) = 2c 01 00 00 00 00 00 00 2012 (REG_BINARY) = 2c 01 00 00 00 00 00 00 2013 (REG_BINARY) = 2c 01 00 00 00 00 00 00 -- Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada This email may be disturbing to some readers as it contains too much technical detail. Reader discretion is advised. [Data in binary units and prefixes, physical quantities in SI.]