Tuesday, December 27, 2011

Linux powers the fastest computers on the planet

Once upon a time, supercomputers used special vector model processors to achieve their remarkable speeds. Then, at the dawn of the 21st century, people began working out how to achieve record-breaking computer speed by linking hundreds or thousands of commercial microprocessors running Linux and connected with high-speed networking in MPP (massively parallel processor) arrays. The supercomputing world has never been the same. Today, Linux rules supercomputing.

The latest "Top 500 supercomputer" list of the fastest computers on the planet makes that abundantly clear. Broken down by operating system, this latest ranking has 469 of the top 500 running one kind of Linux or another.

To be exact, 391 are running their own house brand of Linux. Sixty-two are running some version of Novell's SUSE Linux, including such variants as UNICOS/lc and CNL (Compute Node Linux). Red Hat and its relatives, including CentOS, come in second with 16 supercomputers.

As for the non-Linux members of the fastest computer club, IBM's AIX Unix, with 22 computers, is the only serious competitor. Microsoft and Sun, with Windows HPC 2008 and OpenSolaris, are barely in the running, with fives supercomputers for Windows and a mere pair for OpenSolaris.

Linux isn't just setting the standards; it's breaking the record books. The fastest of the fast is now the Cray XT5 supercomputer, known as Jaguar. Jaguar, which runs CNL, didn't just take first place; it blew away the competition with a top speed of 1.75 petaflops per second, leaving the previous record of 1.04 petaflops per second in the dust. (A petaflop is 1,000 trillion, a quadrillion, floating point calculations per second.)
What's even more amazing is that the IBM Roadrunner, another Linux system, which has held the top record, had only broken the petaflop barrier in the summer of 2008. Or perhaps it isn't so amazing when you consider that, with Linux leading the way, the slowest member of this new list can do 20 teraflop (trillion floating point calculations per second). In other words, this list's slowest system would have ranked No. 336 in the last Top 500 list from six months ago.

Linux and improvements in Linux-based MPP programming techniques can't take all the credit. Jaguar, which is located at the Department of Energy's Oak Ridge Leadership Computing Facility, was upgraded from quad-core to six-core AMD Opteron processors. After this upgrade, Jaguar is running almost a quarter of a million CPU cores. In theory, Jaguar can reach a peak speed of 2.3 petaflop per second.
Between the continued improvements in multi-core processor speeds, network fabric throughput, and Linux performance, we can expect to see supercomputers gaining speed at this remarkable rate for quite some time to come. At this rate, we may see a Linux-powered exaflop (one quintillion calculations per second) computer by the early 2010s. That's not just a theory: IBM is already working on the design for such a supercomputer monster for the Square Kilometre Array telescope project. The proposed operating system? Linux, of course.

Linux powers the fastest computers on the planet

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