The Cray XT3 is a distributed memory

massively parallel Massively parallel is the term for using a large number of computer processors (or separate computers) to simultaneously perform a set of coordinated computations in parallel. GPUs are massively parallel architecture with tens of thousands of t ...

MIMD In computing, multiple instruction, multiple data (MIMD) is a technique employed to achieve parallelism. Machines using MIMD have a number of processors that function asynchronously and independently. At any time, different processors may be exe ...

supercomputer A supercomputer is a computer with a high level of performance as compared to a general-purpose computer. The performance of a supercomputer is commonly measured in floating-point operations per second ( FLOPS) instead of million instructions ...

Cray Inc. Cray Inc., a subsidiary of Hewlett Packard Enterprise, is an American supercomputer manufacturer headquartered in Seattle, Washington. It also manufactures systems for data storage and analytics. Several Cray supercomputer systems are listed i ...

with

Sandia National Laboratories Sandia National Laboratories (SNL), also known as Sandia, is one of three research and development laboratories of the United States Department of Energy's National Nuclear Security Administration (NNSA). Headquartered in Kirtland Air Force Ba ...

under the codename '' Red Storm''. Cray turned the design into a commercial product in 2004. The XT3 derives much of its architecture from the previous

Cray T3E The Cray T3E was Cray Research's second-generation massively parallel supercomputer architecture, launched in late November 1995. The first T3E was installed at the Pittsburgh Supercomputing Center in 1996. Like the previous Cray T3D, it was a ful ...

system, and also from the

Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 seri ...

ASCI Red ASCI Red (also known as ASCI Option Red or TFLOPS) was the first computer built under the Accelerated Strategic Computing Initiative ( ASCI), the supercomputing initiative of the United States government created to help the maintenance of the ...

supercomputer.

XT3

The XT3 consists of between 192 and 32,768 ''processing elements'' (PEs), where each PE comprises a 2.4 or 2.6 GHz

AMD Advanced Micro Devices, Inc. (AMD) is an American multinational semiconductor company based in Santa Clara, California, that develops computer processors and related technologies for business and consumer markets. While it initially manufactur ...

Opteron Opteron is AMD's x86 former server and workstation processor line, and was the first processor which supported the AMD64 instruction set architecture (known generically as x86-64 or AMD64). It was released on April 22, 2003, with the ''SledgeHa ...

processor with up to two cores, a custom "

SeaStar Starfish or sea stars are star-shaped echinoderms belonging to the class Asteroidea (). Common usage frequently finds these names being also applied to ophiuroids, which are correctly referred to as brittle stars or basket stars. Starfish ...

" communications chip, and between 1 and 8 GB of

RAM Ram, ram, or RAM may refer to: Animals * A male sheep * Ram cichlid, a freshwater tropical fish People * Ram (given name) * Ram (surname) * Ram (director) (Ramsubramaniam), an Indian Tamil film director * RAM (musician) (born 1974), Dutch * ...

. The PowerPC 440 based SeaStar device provides a 6.4 gigabyte per second connection to the processor across

HyperTransport HyperTransport (HT), formerly known as Lightning Data Transport, is a technology for interconnection of computer processors. It is a bidirectional serial/parallel high-bandwidth, low- latency point-to-point link that was introduced on April 2 ...

, as well as six 8-gigabyte per second links to neighboring PEs. The PEs are arranged in a 3-dimensional

torus In geometry, a torus (plural tori, colloquially donut or doughnut) is a surface of revolution generated by revolving a circle in three-dimensional space about an axis that is coplanar with the circle. If the axis of revolution does not tou ...

topology, with 96 PEs in each cabinet. The XT3 runs an

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...

called UNICOS/lc that partitions the machine into three sections, the largest comprising the ''Compute nodes'', and two smaller sections for ''Service nodes'' and ''IO nodes''. In UNICOS/lc 1.x, the ''Compute'' PEs run a Sandia developed

microkernel In computer science, a microkernel (often abbreviated as μ-kernel) is the near-minimum amount of software that can provide the mechanisms needed to implement an operating system (OS). These mechanisms include low-level address space management, ...

called Catamount, which is descended from the

SUNMOS SUNMOS (Sandia/UNM Operating System) is an operating system jointly developed by Sandia National Laboratories and the Computer Science Department at the University of New Mexico. The goal of the project, started in 1991, is to develop a highly porta ...

OS of the

Intel Paragon The Intel Paragon is a discontinued series of massively parallel supercomputers that was produced by Intel in the 1990s. The Paragon XP/S is a productized version of the experimental ''Touchstone Delta'' system that was built at Caltech, launched ...

; in UNICOS/lc 2.0, Catamount was replaced by a specially tuned version of Linux called Compute Node Linux (CNL). ''Service'' and ''IO'' PEs run the full version of

SuSE SUSE ( , ) is a German-based multinational open-source software company that develops and sells Linux products to business customers. Founded in 1992, it was the first company to market Linux for enterprise. It is the developer of SUSE Linux Ent ...

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which ...

and are used for interactive logins, systems management, application compiling and job launch. I/O PEs use physically distinct hardware, in that the node boards include

PCI-X PCI-X, short for Peripheral Component Interconnect eXtended, is a computer bus and expansion card standard that enhances the 32-bit PCI local bus for higher bandwidth demanded mostly by servers and workstations. It uses a modified protocol t ...

slots for connections to

Ethernet Ethernet () is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 198 ...

and

Fibre Channel Fibre Channel (FC) is a high-speed data transfer protocol providing in-order, lossless delivery of raw block data. Fibre Channel is primarily used to connect computer data storage to servers in storage area networks (SAN) in commercial data cen ...

networks. Though the performance of each XT3 model will vary with the speed and number of processors installed, the November 2007

Top500 The TOP500 project ranks and details the 500 most powerful non-distributed computing, distributed computer systems in the world. The project was started in 1993 and publishes an updated list of the supercomputers twice a year. The first of these ...

results for the Red Storm machine, the largest XT3 machine installed at Sandia, measured 102.7

teraflops In computing, floating point operations per second (FLOPS, flops or flop/s) is a measure of computer performance, useful in fields of scientific computations that require floating-point calculations. For such cases, it is a more accurate meas ...

on the Linpack benchmark, placing it at #6 on the list. After upgrades in 2008 to install some XT4 nodes with

quad-core A multi-core processor is a microprocessor on a single integrated circuit with two or more separate processing units, called cores, each of which reads and executes program instructions. The instructions are ordinary CPU instructions (such a ...

Opterons, Red Storm achieved 248 teraflops to place at #9 on the November 2008 Top500. The architecture was superseded in 2006 by the

Cray XT4 The Cray XT4 (codenamed ''Hood'' during development) is an updated version of the Cray XT3 supercomputer. It was released on November 18, 2006. It includes an updated version of the SeaStar interconnect router called SeaStar2, processor sockets ...

External links

XT3 at top500.org

* ttp://www.hpc.unm.edu/~tlthomas/buildout/Cray_XT3_Datasheet.pdf Cray XT3Datasheet {{Cray computers Xt3 X86 supercomputers Computer-related introductions in 2004