"Over the past few years, high-performance computing clusters--tightly- or loosely-coupled collections of low-cost, off-the-shelf computers--have largely supplanted proprietary supercomputers. Even with hundreds or even thousands of compute nodes, a commodity hardware HPC cluster is a fraction of the expense of the likes of IBM's Blue Gene or Fujitsu's RIKEN Super Combined Cluster.
"At the same time, Linux features have been greatly expanded and refined. Today, Linux is as capable as any Unix, and because Linux source code is widely and freely available, Linux has also been customized to scale up or scale down to virtually any computer configuration..."
