SGI Altix

SGI Altix
Name	SGI Altix
Manufacturer	Silicon Graphics
Type	Supercomputer
Os	Linux
Cpu	Intel Itanium
Memory	ccNUMA
Year	2003

SGI Altix. The SGI Altix was a pioneering line of Linux-based supercomputers and servers manufactured by Silicon Graphics (SGI) in the early 2000s. It was distinguished by its use of the Intel Itanium processor architecture and a ccNUMA (cache-coherent non-uniform memory access) design that allowed systems to scale to thousands of processors sharing a single Linux kernel image. The platform represented a significant strategic shift for SGI away from its proprietary MIPS architecture and IRIX operating system, aiming to leverage commodity components for high-performance computing.

Overview

Introduced in 2003, the SGI Altix was developed to compete in the rapidly evolving high-performance computing (HPC) market against rivals like IBM, Hewlett-Packard, and Cray Inc.. The system's fundamental innovation was the NUMAlink interconnect, a proprietary technology that enabled the creation of very large, single-system-image ccNUMA machines. This architecture allowed applications to run across hundreds or thousands of Intel Itanium processors as if they were on a single, vast SMP server, simplifying software development and management. Major early deployments included installations at the NASA Ames Research Center and the Lawrence Livermore National Laboratory.

Architecture

The core architectural feature was the NUMAlink interconnect, a high-bandwidth, low-latency fabric that connected nodes containing Intel Itanium processors and memory into a single ccNUMA domain. This design provided a globally shared memory address space across the entire system, which was managed by a modified Linux kernel. Key components included SHUB (Scalable Hub) chips, which acted as the memory and interconnect controllers for each node. The architecture supported extreme scalability, with later configurations like the Altix 4000 series supporting over 1,000 processors and several terabytes of shared memory under one instance of the Linux operating system.

Operating System and Software

The Altix ran a single, global instance of the Linux kernel, specifically a modified version of SUSE Linux Enterprise Server or Red Hat Enterprise Linux optimized for the ccNUMA architecture. This single-system-image approach was a stark contrast to the clustered approaches used by many contemporary Beowulf cluster systems. The ProPack software suite from SGI provided enhanced tools for management, performance analysis, and Message Passing Interface (MPI) communication. Key supported compilers and libraries included the Intel C++ Compiler, the GNU Compiler Collection, and OpenMP for shared-memory parallel programming, enabling a wide range of scientific and engineering applications.

Models and Variants

The initial model was the Altix 3000, which established the basic architecture. It was succeeded by the more scalable Altix 4000 platform, which introduced a modular blade design based on the Intel Itanium 2 processor and increased NUMAlink performance. A significant variant was the Altix ICE (Integrated Compute Environment), introduced later, which marked a shift to a clustered architecture using Intel Xeon processors and InfiniBand networking, moving away from the pure ccNUMA model. Specialized configurations included the Altix 450, a mid-range system, and massive installations like the 10,240-processor Columbia (supercomputer) at NASA.

Applications and Usage

The SGI Altix found primary use in demanding computational science and engineering simulation workloads. Major applications included computational fluid dynamics for aerospace design at organizations like Boeing and NASA, climate modeling at institutions such as the Potsdam Institute for Climate Impact Research, and computational chemistry for pharmaceutical research. The shared-memory architecture was particularly beneficial for large, memory-intensive problems in fields like genomics, finite element analysis, and crash simulation. Notable systems powered the SGI Visualization Center for real-time data analysis and supported government research at the United States Department of Energy.

Historical Context and Impact

The Altix emerged during a period of transition for Silicon Graphics, as the company sought to remain relevant against competitors leveraging commodity x86 hardware and Linux. While technologically impressive for enabling some of the largest SMP systems ever built, the platform's reliance on the commercially struggling Intel Itanium architecture ultimately limited its market longevity. The Altix, particularly the Columbia (supercomputer), demonstrated the viability of large-scale Linux in supercomputing and influenced later HPC designs. However, the shift to the Altix ICE and the eventual acquisition of SGI by Hewlett Packard Enterprise marked the end of the proprietary NUMAlink ccNUMA era, cementing the dominance of clustered x86 architectures in modern high-performance computing.

Category:Supercomputers Category:Computer-related introductions in 2003 Category:Silicon Graphics