Conclave Question

The Papal Conclave starts today. I had read in "Angels and Demons" (Dan Brown) that the process involved the cardinals voting, and then the votes would be burned - some with black-smoke chemical if the vote had not elected the next Pope, or with a white-smoke chemical for a successful ballot. This seemed reasonable enough. But then I got to thinking - spurred on by an article in one of the Sunday newspapers which stated that part of the ritual was each Cardinal had to swear that they would never reveal the goings-on of the Conclave. If one assumes this rule has been in place since the process was first used - how does anyone know what happens? For all anyone knows the process could be quite different - like Cardinal whizzing competitions. When I mentioned this to Sooz she asked if I'd heard about the Nun who goes to the Bishop after she's found two boys holding a competition to see who could whizz the highest up a wall. "And what did you do" asked the Bishop. "I hit the roof" said the Nun. "Good for you" he replied.