Beyond Beowulf Clusters: As clusters grow in size and complexity, it becomes harder and harder to manage their configurations.

In the early ’90s, the Berkeley NOW Project under David Culler posited that groups of less capable machines could be used to solve scientific and other computing problems at a fraction of the cost of larger computers. In 1994, Donald Becker and Thomas Sterling worked to drive the costs even lower by adopting the then-fledgling Linux operating system to build Beowulf clusters at NASA’s Goddard Space Flight Center. By tying desktop machines together with open source tools such as PVM, MPI, and PBS, early clusters—which were often PC towers stacked on metal shelves with a nest of wires interconnecting them—fundamentally altered the balance of scientific computing. Before these first clusters appeared, distributed/parallel computing was prevalent at only a few computing centers, national laboratories, and a very few university departments. Since the introduction of clusters, distributed computing is now, literally, everywhere.