IBM built the computer for the U.S. Department of Energy's (DOE) National Nuclear Security Administration.[4][5] It is a hybrid design with 12,960 IBM PowerXCell[6] 8i CPUs and 6,480 AMD Opteron dual-core processors[7] in specially designed server blades connected by Infiniband. The Roadrunner uses Red Hat Enterprise Linux along with Fedora as its operating systems and is managed with xCAT distributed computing software.