One of the primary challenges to achieving exascale computing is designing new architectures that will work under the enormous power and cost constraints. The mission of co-design is to absorb the sweeping changes necessary for exascale computing into software and to ensure that the hardware will meet the requirements to perform extreme scale applications. This session focuses on multi-disciplinary research required to co-design all aspects of simulation including numerical algorithms for PDE's, domain specific programming languages, asynchronous programming environments, and scientific data management and analytics for in situ uncertainty quantification (UQ).