DRESDEN, Germany (AP) — Hewlett-Packard Co. improved its standing on the latest list of the world's 500 fastest supercomputers.IBM Corp. still dominates with six of the top 10, including the BlueGene/L computer at the Lawrence Livermore nuclear lab. It remained the world's fastest computer by performing a standard benchmark operation at 280 teraflops — 280 trillion calculations per second.

IBM used the occasion to announce it expects to break the petaflop barrier — a quadrillion calculations per second — as early as 2008 with BlueGene/P, its next supercomputing family. At its maximum scale, IBM said, BlueGene/P could reach 3 petaflops, a potential boon for complex simulations in drug research and energy exploration.

Next on the new list, released on Wednesday at a conference in Dresden, were two machines made by Cray Inc. for other US national labs — a 102-teraflop system at Oak Ridge and 101-teraflops at Sandia.

But the rest of the list was hugely IBM and Hewlett-Packard. HP became the leading manufacturer in the top 500, with 41 percent to IBM's 38 percent.