Newbie questions

[Philippe de Rochambeau]

Hello,

could someone please tell me:

- why the TZ environment variable is empty before you set it

- why setting it does not seem to affect the system's internal timezone

- what the zoneinfo daemon, if there is such a thing, is called

- how zoneinfo knows that the TZ variable has been set

- if you can query the daemon directly

- if you can retrieve data, such as a city's coordinates, from it

- if there is a way to retrieve the list of values you can set TZ to, 
apart from going through the directories in /usr/share/zoneinfo and 
using the file names as values

I am using Macosx 10.3.

Many thanks.

Philippe