Future Challenges in Software and Computing for the ATLAS Experiment at the LHC

The High Luminosity Upgrade to the Large Hadron Collider (HL-LHC) and to the ATLAS experiment are expected to be completed in 2026. After this major upgrade, processing and analysis of data and Monte Carlo simulations will be extremely challenging, and is estimated to require scaling up computing systems and software by an order of magnitude. Innovations in software, new data processing models, and re-engineering of current software applications and computing resources will be needed to meet these challenges. This talk will outline the range of possibilities that will be explored by ATLAS for the HL-LHC in the next 5 years. New processing models will be described that increase efficiency and reduce cost. Software re-engineering based on new technologies hold the promise to reduce computation time of many applications. Optimizing the use of evolving computing architecture will increase resources available to the field of High Energy Physics (HEP). ATLAS is entering a period of research and development in software and computing, to be followed by prototypes and testing for the HL-LHC. A new paradigm for computing in HEP may emerge from this unprecedented effort to meet the challenges of the HL-LHC. This talk will present a framework for the path forward.