The Grand Challenge and the large-scale-production users are expected to be computer literate. The HPCAC staff will likely know these users because they have worked together to solve production and development problems and to optimize the code for the hardware configurations available through the HPCAC; in the case of the Grand Challenge applications such an activity may be mandated by the Center. Also the users and NERSC staff may have worked together to integrate visualization tools with the applications code.
Medium scale and small scale users may rely heavily on third party applications and discipline specific applications. They are larger in number than the GC and large scale production users, and their interaction with the HPCAC staff will be as great or greater than the former two classes. The level of computer literacy among these users will span the full gamut.
As users develop projects they are likely to migrate up from the Small-scale to Mid-scale and Grand Challenge projects. Additionally, these divisions are somewhat arbitrary and there is a ``gray'' area at the transition between these areas. For example, a small-scale user might migrate his application to the MPP starting with a modest initial allocation. Once his/her application scales and is efficient the next years allocation would move to a medium or large scale project allowing scientific testing and validation of the models in the application. If the models provide a solution to a grand-challenge-scale project then that transition should also be forthcoming.