Before revision:  Despite the prolific literature, the question remains open whether cloud computing can provide HPC-competitive performance for a wide range of scientific applications. The answer to this question is crucial in guiding the design of future systems and providing access to high-performance resources to a broadened community.
After revision:  Despite the prolific literature, the question remains open . Answers are crucial for designing future systems and providing access to high-performance resources to a broadened community.