Operating system used by the top 20 supercomputers Rank Computer Vendor Operating System 1 Roadrunner IBM Linux 2 Jaguar (Cray XT5) Cray Linux (CNL) 3 JUGENE IBM Linux (CNK/SLES 9) 4 Pleiades SGI Linux (SLES 10 + SGI ProPack 5) 5 BlueGene/L IBM Linux (CNK/SLES 9) 6 Kraken XT5 Cray Linux (CNL) 7 BlueGene/P IBM Linux (CNK/SLES 9) 8 Ranger Sun Linux 9 Dawn IBM Linux (CNK/SLES 9) 10 JUROPA Bull SA Linux (SLES 11) 11 Franklin Cray Linux (CNL) 12 Jaguar (Cray XT4) Cray Linux (CNL) 13 Red Storm Cray Linux (UNICOS/SUSE Linux) 14 Shaheen IBM Linux (CNK/SLES 9) 15 Magic Cube Dawning Windows (Windows HPC 2008) 16 GPC IBM Linux 17 Encanto SGI Linux (SLES 10 + SGI ProPack 5) 18 EKA HP Linux 19 Juno Appro International Linux (Redhat) 20 Jade SGI Linux (SLES 10 + SGI ProPack 5)