[Samba] where is an explain of the tdb -files in Samba?

[yeno at gmx.net]

Hi.
At looking for a solution of a problem with samba, I cant find a explain
of what contains the .tdb-files. Okay, the secret.tdb contains the
Domain Sid. What else? The group_mappings.tdb contains now in Samba 3
the translation from unix-Groups to windows groups. What are the defaults?
The connection.tdb is the intern table of what smbstatus show me. (Is
this correkt?). Why are there a registry.tdb?

Where can I read about that? The Howto doesn't talk much about this and
Google only gives me advertisments of Viagra-pills :/
(If I take them, will I get the answer? *g*)

greetings
Andy P.