How does Oracle know who I am? Slightly unimportant but it's piqued my curiousity.

I've just logged into an Oracle 10g database for the first time using the Oracle SQL Developer Tools.

I used a generic user login which isn't my name (nottstest2), from a machine that is called something that isn't my name (courgette). My name is nowhere in the database and isn't associated with the login.

Yet, the server logs show a connection from "Jon Hopkins".

How does it know who I am? Is it being pulled from my Windows login in some way (though I'm not using single sign in)?
How do you log onto courgette?  Would that username identify you?

You can check that by running

select sys_context('userenv', 'os_user') 
from dual;


The USERENV namespace can retrieve a lot of different information about the user and their environment.  Find out more.