A fascinating talk, or maybe a tutorial on how the world of market risk works within BNP Paribas . By outlining clearly the problem space and problems faced by IT departments in the banking world;procurement and strategic sign-off and procurement. You got a good feel for how the architecture came together. In this case i felt that the open source decisions, many made due to restrictions, lead ultimately to success and what i would expect to be a happy development team. Probably the most surprising part of the architecture where a set of processes running from Java Main; it seemed to have come about as application servers where the remit of another team, and asking them for involvement was not an option.