Do you believe a roadmap exists that will get us to Exascale?
A roadmap may incorporate the design and establish the sequence of actions required to manufacture such a design based on expectation of the enabling technologies at the time to completion. The cost, MTBF, and power unspecified, this roadmap need only satisfy the criterion of a workload class that can deliver 1018 operations per second. Such roadmaps have been suggested by colleagues on both sides of the Pacific Rim. Such a system if too narrow in application, too difficult to program, too limited in uninterrupted execution time, consuming too much power to be deployable at but a few sites, and too expensive to acquire and operate may be considered a “stunt machine” whose principal value is a form of shallow and brief status. Within this perspective, I think the answer is “yes”, there is a roadmap (perhaps several) to realize an exascale stunt machine sometime around the end of this decade.