The U.S. Department of Defense recently turned on two large Linux clusters for some of its advanced battlefield simulation programs.The Linux Networx Evolocity clusters both include 256 dual-processor Intel Xeon 3-GHz processors. The nodes are connected via Gigabit Ethernet links and are managed by Linux Networx's IceBox cluster management system, which allows nodes to be taken offline and put back in service without disrupting processes running on the cluster as a whole.One of the machines will be installed in the U.S Air Force's Maui High Performance Computing Center in Hawaii. The other will go to Wright-Patterson Air Force Base in Dayton, Ohio, where the DOD's Aeronautical Systems Center Major Shared Resource Center is located.The two boxes will replace a single 512-processor cluster used by the DOD. The new clusters will run programs that simulate battles with as many as 1 million soldiers, as well as aircraft, ships and tanks. The DOD says the new cluster will greatly increase the number of troops it can simulate in a battle, but the agency did not specify the cluster's total simulation capacity.The cluster deal represents another big government contract for Salt Late City-based Linux Networx. Earlier this year, the company delivered a Linux cluster with more than 2,000 Linux processors to the U.S. Army. The vendor has a contract to deliver a total of six Linux supercomputers to the DOD.