Open-source software and off-the-shelf hardware make strong showing among the best of the biggest.
The Blue Gene/L succession, while expected, reflects IBM's sustained push in recent years to expand its expertise from business computers into high-performance technical computing. On the newest incarnation of the Top500 list, updated twice a year, IBM has 216 systems, which account for 49.4 percent of list members' collective performance.
The ascendance also highlights the rise of Linux, the open-source operating system that Blue Gene/L runs and that IBM helped to champion. The new No. 2 system, Silicon Graphics' Columbia, also uses Linux.
Blue Gene/L performed 70.7 trillion calculations per second, or teraflops, nearly twice the 35.9 teraflops of Earth Simulator. And as expected, Columbia was clocked at 51.9 teraflops. IBM's new MareNostrum, at 20.5 teraflops, arrived in fourth place.
The Top500 list is compiled by Hans Meuer of the University of Mannheim in Germany, Erich Strohmaier and Horst Simon of Lawrence Berkeley National Laboratory, and Jack Dongarra of the University of Tennessee. It was released Monday at the SC2004 supercomputing conference in Pittsburgh. Computers are scored by the Linpack benchmark, a convenient measurement but even list organizers recognize it is an incomplete measurement of real-world ability.
Top-end supercomputers use thousands of processors, draw power measured in megawatts and occupy entire floors of buildings. But less and less often are they based on exotic or specialized computing technology. A total of 236 of the 500 systems use the same Intel Xeon processors that show up in the majority of off-the-shelf servers. That's up from 226 in the June list. Systems using Intel Itanium processors, another mainstream alternative and the chip used in Columbia, increased from 61 to 87 over the same period.
Thirty systems use Advanced Micro Devices' Opteron--another common server chip--compared to 32 in June. IBM's Power family of processors are used in 62 systems, down from 75 in June.
Supercomputers assembled from these more ordinary components are connected into massive clusters that pass messages and share each others' memory over high-speed networks. Clusters now account for 296 of the 500 systems on the list.
IBM and HP dominate the computer manufacturers on the list. IBM slipped from 224 systems in June to 216 systems, while HP grew from 140 to 173.
In the entire supercomputing market, Big Blue is getting bigger and nearing HP's top rank. From 2002 to 2003, IBM's share of the market grew from 28.2 percent to 30.2 percent with sales of $1.62 billion, according to IDC. HP, with $1.79 billion in revenue for 2003, shrank slightly from 33.6 percent to 33.5 percent.
A few years ago, a "terascale" computer--one that could perform more than a trillion calculations per second--was a remarkable achievement. Indeed, in 1993, the total performance of all 500 machines was 1.12 teraflops.
Now, 398 of the systems on the list have crossed the teraflop threshold, and the total performance has reached 1.13 petaflops, or quadrillion calculations per second.
The slowest machine on the list was 851 gigaflops, or 0.851 teraflops.
Japan long has had a place on the list, but now other Asian countries are rising. Thirty of the top machines were in Japan and 57 in other Asian countries, including 17 in China.