September 21, 2016 | The path to exascale computing hasn't been an easy one. It has had to face a daunting set of challenges in energy efficiency, application parallelism, and system reliability, just to name a few. The difficulties in bringing the hardware and software up to this level is considerable, but there is a more fundamental challenge at the heart of exascale: doing the necessary work of building an ecosystem that will last for a decade or more, not just for a handful stunt machines. TOP500