A few years back, I started digging into how many of the world’s fastest supercomputers were using Linux. At the time, the list organizers did not break the super systems down by OS, so we measured by clusters, nearly all of which were running Linux. It quickly became evident that Linux clusters were the dominant approach, and were also the basis of the top systems, including IBM’s Blue Gene.

A subsequent check of the Top500 Supercomputer list a year later, when list editors added OS as one of the system features tracked, showed that Linux was used in nearly 80% of the world’s the fastest and most efficient HPC systems. There have still been super systems running AIX, Unix and other operating systems as well as non-clustered, more traditional supercomputers on the list. There has also been a push from Microsoft to give its Windows Compute Cluster Server a name and place in HPC.

It was Linux, however, that this week got another endorsement of HPC in a different form: supercomputer stalwart Cray rolled out its super scalable XT5 supercomputer that runs Linux. In the company’s biggest use of Linux to date, Cray is using AMD quad-core processors in a configuration of more than 1,000 CPUs to top 40 teraflops of performance.

The most recent Top500 list shows Linux is still the outright leader of operating systems. With the new list to be released next week and companies such as Cray looking to Linux in a variety of ways, there is no doubt Linux rules the HPC market. The real beauty is that this dominance is based almost purely on technical and innovative merit, not one company’s or consortium’s monopoly hold.