Feds' computers are most super

The U.S. government is using the four most powerful supercomputers in the world, according to a new list that ranks the top 500 worldwide.

Researchers at the University of Tennessee and the University of Mannheim, Germany, released the Top500 List (www.top500.org) today. Here are the top four, all located at U.S. Energy Department facilities:

1. IBM Corp.'s ASCI White machine at Lawrence Livermore National Laboratory.

2. Another IBM supercomputer — used to simulate gasoline combustion — at the National Energy Research Scientific Center.

3. Intel Corp.'s ASCI Red at Sandia National Laboratories.

4. IBM's ASCI Blue at Lawrence Livermore.

Federal agencies are housing half of the top 50 most powerful supercomputers, including eight of the top 10.

IBM dominates the overall list with 201 of the world's 500 most powerful supercomputers and also leads the federal market, having produced 15 of the government installations that finished in the top 50.

In addition to Intel's lone government entry in the top 50, Cray Inc., Silicon Graphics Inc. and Compaq Computer Corp. have government machines in the top 10 percent of the list. Sandia is in at No. 42 with a self-made machine.

Researchers use the Linpack benchmark to formulate the Top500 List. The benchmark "allows the user to scale the size of the problem and to optimize the software in order to achieve the best performance for a given machine," according to the Top500 Web site (www.top500.org/lists/linpack.html).

This does not reflect the "overall performance" of a given system, but does reflect the "performance of a dedicated system for solving a dense system of linear equation." The benchmark winds up providing a comparable set of performance numbers across all computers.