Cray X1
Encyclopedia
The Cray X1 is a non-uniform memory access
Non-Uniform Memory Access
Non-Uniform Memory Access is a computer memory design used in Multiprocessing, where the memory access time depends on the memory location relative to a processor...

, vector processor
Vector processor
A vector processor, or array processor, is a central processing unit that implements an instruction set containing instructions that operate on one-dimensional arrays of data called vectors. This is in contrast to a scalar processor, whose instructions operate on single data items...

 supercomputer
Supercomputer
A supercomputer is a computer at the frontline of current processing capacity, particularly speed of calculation.Supercomputers are used for highly calculation-intensive tasks such as problems including quantum physics, weather forecasting, climate research, molecular modeling A supercomputer is a...

 manufactured and sold by Cray Inc.
Cray
Cray Inc. is an American supercomputer manufacturer based in Seattle, Washington. The company's predecessor, Cray Research, Inc. , was founded in 1972 by computer designer Seymour Cray. Seymour Cray went on to form the spin-off Cray Computer Corporation , in 1989, which went bankrupt in 1995,...

 since 2003. The X1 is often described as the unification of the Cray T90
Cray T90
The Cray T90 series was the last of a line of vector processing supercomputers manufactured by Cray Research, Inc, superseding the Cray C90 series...

, Cray SV1
Cray SV1
The Cray SV1 is a vector processor supercomputer from the Cray Research division of Silicon Graphics introduced in 1998. The SV1 has since been succeeded by the Cray X1 and X1E vector supercomputers. Like its predecessor, the Cray J90, the SV1 used CMOS processors, which lowered the cost of the...

, and Cray T3E
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 fully distributed memory machine using a 3D torus...

 architectures into a single machine. The X1 shares the multistreaming processors, vector caches, and CMOS
CMOS
Complementary metal–oxide–semiconductor is a technology for constructing integrated circuits. CMOS technology is used in microprocessors, microcontrollers, static RAM, and other digital logic circuits...

 design of the SV1, the highly scalable distributed memory design of the T3E, and the high memory bandwidth
Bandwidth (computing)
In computer networking and computer science, bandwidth, network bandwidth, data bandwidth, or digital bandwidth is a measure of available or consumed data communication resources expressed in bits/second or multiples of it .Note that in textbooks on wireless communications, modem data transmission,...

 and liquid cooling of the T90.

The X1 uses 1.2 ns (800 MHz) clock cycle, and 8-wide vector pipes in MSP mode, offering a peak speed of 12.8 gigaflops per processor. Air-cooled models are available with up to 64 processors. Liquid-cooled systems scale to a theoretical maximum of 4096 processors, comprising 1024 shared-memory nodes
Node (networking)
In communication networks, a node is a connection point, either a redistribution point or a communication endpoint . The definition of a node depends on the network and protocol layer referred to...

 connected in a two-dimensional torus
Torus
In geometry, a torus is a surface of revolution generated by revolving a circle in three dimensional space about an axis coplanar with the circle...

 network, in 32 frames. Such a system would supply a peak speed of 50 teraflops
FLOPS
In computing, FLOPS is a measure of a computer's performance, especially in fields of scientific calculations that make heavy use of floating-point calculations, similar to the older, simpler, instructions per second...

. The largest unclassified X1 system was the 512 processor system at Oak Ridge National Laboratory
Oak Ridge National Laboratory
Oak Ridge National Laboratory is a multiprogram science and technology national laboratory managed for the United States Department of Energy by UT-Battelle. ORNL is the DOE's largest science and energy laboratory. ORNL is located in Oak Ridge, Tennessee, near Knoxville...

, though this has since been upgraded to an X1E system.

The X1 can be programmed either with widely used message passing software like MPI
Message Passing Interface
Message Passing Interface is a standardized and portable message-passing system designed by a group of researchers from academia and industry to function on a wide variety of parallel computers...

 and PVM
Parallel Virtual Machine
The Parallel Virtual Machine is a software tool for parallel networking of computers. It is designed to allow a network of heterogeneous Unix and/or Windows machines to be used as a single distributed parallel processor. Thus large computational problems can be solved more cost effectively by...

, or with shared-memory languages like Unified Parallel C
Unified Parallel C
Unified Parallel C is an extension of the C programming language designed for high-performance computing on large-scale parallel machines, including those with a common global address space and those with distributed memory...

 programming language or Co-array Fortran
Co-array Fortran
Co-array Fortran , formerly known as F--, is an extension of Fortran 95/2003 for parallel processing created by Robert Numrich and John Reid in 1990s...

. The X1 runs an operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

 called UNICOS/mp
Unicos
UNICOS is the name of a range of Unix-like operating system variants developed by Cray for its supercomputers. UNICOS is the successor of the Cray Operating System . It provides network clustering and source code compatibility layers for some other Unixes. UNICOS was originally introduced in 1985...

 which shares more with the SGI
Silicon Graphics
Silicon Graphics, Inc. was a manufacturer of high-performance computing solutions, including computer hardware and software, founded in 1981 by Jim Clark...

 IRIX
IRIX
IRIX is a computer operating system developed by Silicon Graphics, Inc. to run natively on their 32- and 64-bit MIPS architecture workstations and servers. It was based on UNIX System V with BSD extensions. IRIX was the first operating system to include the XFS file system.The last major version...

 operating system than it does with the UNICOS
Unicos
UNICOS is the name of a range of Unix-like operating system variants developed by Cray for its supercomputers. UNICOS is the successor of the Cray Operating System . It provides network clustering and source code compatibility layers for some other Unixes. UNICOS was originally introduced in 1985...

 found on prior generation Cray machines.

In 2005, Cray released the X1E upgrade, which uses dual-core processors, allowing two quad-processor nodes to fit on a node board. The processors are also upgraded to 1150 MHz. This upgrade almost triples the peak performance per board, but reduces the per-processor memory and interconnect bandwidth. X1 and X1E boards can be combined within the same system.

The X1 is notable for its development being partly funded by United States
Government's National Security Agency (under the code name
SV2).
The X1 was not a financially successful product and it seems doubtful that it
or its successors would have been produced without this support.

External links

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