November 15, 2005

Linux continues supercomputer domination

Author: Jay Lyman

Linux is on top, once again. On the bi-annual Top500 List, just released at the
Supercomputing Conference in Seattle, IBM's Linux-powered Blue Gene/L
retains the top slot. Blue Gene/L is not alone, as seven of the top 10
systems are running Linux. AIX, UNICOS, and Super-UX also appear in the top

The last few Top500 Supercomputer Site lists left little doubt that Linux
is the operating
system of choice
for these bleeding edge systems, but the latest list
highlights the popularity of Linux in supercomputing and cites it as the OS
of choice for 78% of the world's fastest machines. 391 of the systems rely on
Linux of one flavor or another -- far more than Unix (yesterday's
supercomputing king), Mac OS X, Solaris, or any others. Microsoft Windows didn't
even turn up on the list.

Erich Strohmaier, list co-founder and editor, said that although 64-bit and
multi-core processors are playing a larger role in the evolution of the
supersystems, there are no signs that Linux will be dropping down the
list. "Linux is the dominating OS in the supercomputing community and will keep
this role," he said. "If anything, it will only enlarge its prevalence."

Strohmaier credited the cost-effectiveness of using Linux clusters to
achieve greater processing power, and noted that the open source
operating system also matches what many organizations already run on their

While he said it is difficult to determine exactly which distributions of
Linux are being used, the Top500 site's database now includes a
breakdown of the speedy supercomputers by operating system. The database also
includes variables such as geographic region, system vendor, interconnect
technology, and computer and processor families.

Within Linux, different distributions and variations on the list include:
Red Hat Linux, Red Hat Enterprise 3, SUSE Enterprise Server 8 and 9,
UNICOS/Linux, and CNK/Linux. Strohmaier indicated it is standard Linux,
rather than customized or combined uses of the open source operating system,
that is most popular in the ultra high-end computing market.

"Customization is something the research community likes to do, but
commercial and industrial customers are more interested in getting a
particular solution that's supported," he said.

Strohmaier added he was somewhat surprised that the supercomputing
industry has continued to grow with such strength. He also reported
significant supercomputer turnover, as four of the top 10 fastest systems
were displaced by new installations, and the last 221 systems from the June
2005 list were now too small to make the cut.

To maintain its top spot, IBM's BlueGene/L at Lawrence Livermore National
Lab (LLNL) doubled in size, and is now capable of record Linpack performance
of 280.6 teraflops (trillions of calculations per second). Second on the
latest list is a similar, Linux-based eServer Blue Gene system, BGW, at
IBM's Thomas Watson Research Center, which reached 91.2 teraflop performance.
Third is the Department of Energy's ASCI Purple, an AIX-powered system that
reached 63.4 teraflop performance, also at LLNL. The number four and five
spots are held by SGI's Columbia, a Linux-powered
supercomputer that managed 51.87 teraflops, and Thunderbird, Sandia National
Lab's Dell PowerEdge system that runs on Linux and hit 36.10 teraflops.

Strohmaier also noted the increased presence of AMD processors on the
list. AMD's showing pales compared to Intel's 333 systems, but the company garnered 55
spots on the list and its share is growing. Strohmaier said 64-bit and
multi-core technologies were a factor in the trend, but he thinks that the impact of
new dual-core and multi-core processors had not yet played out on the list.

Strohmaier indicated that while Unix still holds its own on the list, no
other operating system is likely to be used as much as Linux in the
foreseeable Top500 future.

"Older Unix variations such as AIX are still used to some extent, but as
server based systems are replaced by clusters, Linux becomes more and more
dominant," he said. "Linux has become an industry standard in
this community, and any other OS trying to break into this market (Mac OS X,
Windows, etc.) would have to fight a steep, uphill battle."