I’ve long followed and blogged about the prominence of Linux in supercomputing and the twice-annual Top500 Supercomputer List. In a relatively short time frame, the open source OS has shot to the top of the Top500 list thanks to its free availability, flexibility, stability, scalability and conduciveness for clustering. Over time, the tools and statistics provided by the fine folks that track the world’s most powerful computers have also improved. With the latest list released this month, we even get a nice graphical representation of things and trends.

It was more of the same this year, in a kind of role reversal where Linux leads and Windows is trying to squeeze into the market. In the June 2008 Top500 list, Linux still lives large with a role in 92% of systems (It is the only OS for 85.4%, but when considering all distributions (SUSE, Red Hat, CentOS, and general ‘Linux,’ as well as mixed uses that include Linux, I figure the share is more like the 92%). Linux is the OS of the top four systems, and it is used in nine out of the top 10. Windows Compute Cluster Server 2003 and Windows HPC 2008 combined for five of the top systems and a 1% share. Other operating systems that make the list include AIX (almost 5%) and other Unix versions and MacOS X, used on a couple of Top500 systems. Other list highlights included continued growth of Intel processors, used in 75% of the Top500 systems, and energy efficiency, which is now being improved by system builders and tracked by list maintainers.

The other most notable fact about the latest list is that thanks to the No. 1 Roadrunner system from IBM and the U.S. Department of Energy’s Los Alamos National Laboratory, we’ve crossed the petaflop mark. As the supercomputing power goes up, energy and cooling demands go down and the hardware and interconnect software advances, Linux is still serving as the bedrock for the highest of high-performance computing systems.