ATLAS trigger simulation with legacy code using virtualization techniques

Abstract. Several scenarios, both present and future, requires re-simulation of the trigger response in ATLAS. While software for the detector response simulation and event reconstruction is allowed to change and improve, the trigger response simulation has to reflect the conditions at which data was taken. This poses a massive maintenance and data preservation problem. Several strategies have been considered and a proof-of-concept model using CernVM has been developed. While the virtualization with CernVM elegantly solves several aspects of the data preservation problem, the low maturity for contextualization as well as data format incompatibilities in the currently used data format introduces new challenges. In this proceeding these challenges, their current solutions and the proof of concept model for precise trigger simulation are discussed.