2 IBM Power Systems 775 for AIX and Linux HPC Solution1.1 Overview of the IBM Power System 775 SupercomputerFor many years, IBM provided High Performance Computing (HPC) solutions that provideextreme performance. For example, highly scalable clusters by using AIX and Linux fordemanding workloads, including weather forecasting and climate modeling.The previous IBM Power 575 POWER6 water-cooled cluster showed impressive density andperformance. With 32 processors, 32 GB to 256 GB of memory in one central electroniccomplex (CEC) enclosure or cage, and up to 14 CECs per Frame (water-cooled), 448processors per frame was possible.The InfiniBand interconnect provided the cluster with powerful communication channels forthe workloads.The new Power 775 Supercomputer from IBM takes the density to a new height. With 2563.84 GHz POWER7® processors, 2 TB of memory per CEC, and up to 12 CECs per Frame, atotal of 3072 processors and 24 TBs memory per Frame is possible. Highly scalable with thecapability to cluster 2048 CEC drawers together makes up 524,288 POWER7 processors todo the work to solve the most challenging problems. A total of 7.86 TF per CEC and 94.4 TFper rack highlights the capabilities of this high-performance computing solution.The hardware is only as good as the software that runs on it. IBM AIX, IBM FileNet ProcessEngine (PE) Runtime Edition, LoadLeveler, GPFS, and xCAT are a few of the supportedsoftware stacks for the solution. For more information, see 1.9, “High Performance Computingsoftware stack” on page 62.1.2 The IBM Power 775 cluster componentsThe IBM Power 775 can consist of the following components: Compute subsystem:– Diskless nodes dedicated to perform computational tasks– Customized operating system (OS) images– Applications Storage subsystem:– I/O node (diskless)– OS images for IO nodes– SAS adapters attached to the Disk Enclosures (DE)– General Parallel File System (GPFS) Management subsystem:– Executive Management Server (EMS)– Login Node– Utility Node Communication Subsystem:– Host Fabric Interface (HFI):• Busses from processor modules to the switching hub in an octant• Local links (LL-links) between octants• Local remote links (LR-links) between drawers in a SuperNode• Distance links (D-links) between SuperNodes– Operating system drivers– IBM User space protocol– AIX and Linux IP drivers