When I was a reporter a few years ago, I began covering the fast rise of Linux to dominance on the Top500 Supercomputer list. Since the list comes out every six months, I would end up getting a response like, “Is it that time of year again already?” to which I would respond, yes. My previous editor’s exasperation aside, I thought it was incredibly significant to see Linux with as much if not more dominance as Microsoft in a market. The fact that it’s the high end of high-performance computing (HPC) only increases the significance, in my opinion, since it is generally a harbinger of things to come in more mainstream enterprise IT. So, is it that time of year again? You bet.

The latest list indicates growing Linux dominance. Linux is used in the top nine supercomputer systems in the world. When considered as the primary OS or part of a mixed-OS supersystem, Linux is now present in 469 of the supercomputer sites, 93.8% of the Top500 list. This represents about 10 more sites than in November 2007, when Linux had presence in 91.8% of the systems. In fact, Linux is the only operating system that managed gains in the November 2008 list. A year ago, Linux was the OS for 84.6% of the top supercomputers. In November 2008, the open source OS was used in 87.8% of the systems. Compare this to Unix, which dropped from 6% to 4.6%, mixed-OS use which dropped from 7.2% to 6.2% and other operating systems, including BSD, Mac OS X and Windows, which were all down this year from the November 2007 list.

While ‘Linux’ in general grew its share of the Top500 sites, we also saw the top Linux vendors losing some ground, perhaps indicative of the ‘Rise of Community Linux’ we discuss in our CAOS 8 report. In fact, while SUSE Linux fell from use in 62 systems a year ago to use in 52 systems on the latest list and Red Hat dropped from 13 systems down to six, the November 2008 list includes five systems using CentOS, giving it 1% share of the list. CentOS, Debian and other distributions are likely also part of the general Linux category in the Top500 data.

Another interesting change in this list: while Sun’s Solaris disappeared from the list in November 2008 after securing two slots on the November 2007 list, the open source OpenSolaris OS managed to get on the latest Top500 list with one system.

There are certainly a number of factors, described here succinctly by Gordon Haff, that are playing into the progress of supercomputing, but based on the Top500 list and what we hear from vendors, users and communities, the move to Linux and open operating systems in supercomputing shows no signs of slowing down, stalling or otherwise getting un-super.