Cray XMT
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Cray XMT
Cray XMT (''Cray eXtreme MultiThreading'', codenamed ''Eldorado'') is a scalable multithreaded shared memory supercomputer architecture by Cray, based on the third generation of the Tera MTA architecture, targeted at large graph problems (e.g. semantic databases, big data, pattern matching).Maltby, James (2012). Cray XMT Multithreated programming model'' "Using the next-generation Cray XMT (uRiKA) for Large Scale Data Analytics." Swiss National Supercomputing Centre. Presented in 2005, it supersedes the earlier unsuccessful Cray MTA-2. It uses the Threadstorm3 CPUs inside Cray XT3 blades. Designed to make use of commodity parts and existing subsystems for other commercial systems, it alleviated the shortcomings of Cray MTA-2's high cost of fully custom manufacture and support. It brought various substantial improvements over Cray MTA-2, most notably nearly tripling the peak performance, and vastly increased maximum CPU count to 8,192 and maximum memory to 128 TB, with a data ...
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Cray MTA-2
The Cray MTA-2 is a shared-memory MIMD computer marketed by Cray Inc. It is an unusual design based on the Tera computer designed by Tera Computer Company. The original Tera computer (also known as the ''MTA'') turned out to be nearly unmanufacturable due to its aggressive packaging and circuit technology. The MTA-2 was an attempt to correct these problems while maintaining essentially the same processor architecture respun in one silicon ASIC, down from some 26 gallium arsenide ASICs in the original MTA; and while regressing the network design from a 4-D torus topology to a less efficient but more scalable Cayley graph topology. The name ''Cray'' was added to the second version after Tera Computer Company bought the remains of the Cray Research division of Silicon Graphics in 2000 and renamed itself Cray Inc. The MTA-2 was not a commercial success, with only one moderately-sized 40-processor system ("Boomer") being sold to the United States Naval Research Laboratory in 2002, and ...
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SUSE Linux Enterprise
SUSE Linux Enterprise (often abbreviated to SLE) is a Linux-based operating system developed by SUSE. It is available in two editions, suffixed with Server (SLES) for servers and mainframes, and Desktop (SLED) for workstations and desktop computers. Its major versions are released at an interval of 3–4 years, while minor versions (called "Service Packs") are released about every 12 months. SUSE Linux Enterprise products receive more intense testing than the upstream openSUSE community product, with the intention that only mature, stable versions of the included components will make it through to the released enterprise product. It is developed from a common code base with other SUSE Linux Enterprise products. IBM's Watson was built on IBM's POWER7 systems using SLES. In March 2018, SUSE Product Manager Jay Kruemcke wrote in SUSE blog that SUSE Linux Enterprise developers have ported it to Raspberry Pi. SUSE Linux Enterprise Server SLES was developed based on SUSE Linux by ...
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Multiply–accumulate Operation
In computing, especially digital signal processing, the multiply–accumulate (MAC) or multiply-add (MAD) operation is a common step that computes the product of two numbers and adds that product to an accumulator. The hardware unit that performs the operation is known as a multiplier–accumulator (MAC unit); the operation itself is also often called a MAC or a MAD operation. The MAC operation modifies an accumulator ''a'': :\ a \leftarrow a + ( b \times c ) When done with floating point numbers, it might be performed with two roundings (typical in many DSPs), or with a single rounding. When performed with a single rounding, it is called a fused multiply–add (FMA) or fused multiply–accumulate (FMAC). Modern computers may contain a dedicated MAC, consisting of a multiplier implemented in combinational logic followed by an adder and an accumulator register that stores the result. The output of the register is fed back to one input of the adder, so that on each clock cycle, ...
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FLOPS
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 measure than measuring instructions per second. Floating-point arithmetic Floating-point arithmetic is needed for very large or very small real numbers, or computations that require a large dynamic range. Floating-point representation is similar to scientific notation, except everything is carried out in base two, rather than base ten. The encoding scheme stores the sign, the exponent (in base two for Cray and VAX, base two or ten for IEEE floating point formats, and base 16 for IBM Floating Point Architecture) and the significand (number after the radix point). While several similar formats are in use, the most common is ANSI/IEEE Std. 754-1985. This standard defines the format for 32-bit numbers called ''single precision'', as well as 6 ...
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Context Switch
In computing, a context switch is the process of storing the state of a process or thread, so that it can be restored and resume execution at a later point, and then restoring a different, previously saved, state. This allows multiple processes to share a single central processing unit (CPU), and is an essential feature of a multitasking operating system. The precise meaning of the phrase "context switch" varies. In a multitasking context, it refers to the process of storing the system state for one task, so that task can be paused and another task resumed. A context switch can also occur as the result of an interrupt, such as when a task needs to access disk storage, freeing up CPU time for other tasks. Some operating systems also require a context switch to move between user mode and kernel mode tasks. The process of context switching can have a negative impact on system performance. Cost Context switches are usually computationally intensive, and much of the design of opera ...
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Multithreading (computer Architecture)
In computer architecture, multithreading is the ability of a central processing unit (CPU) (or a single core in a multi-core processor) to provide multiple threads of execution concurrently, supported by the operating system. This approach differs from multiprocessing. In a multithreaded application, the threads share the resources of a single or multiple cores, which include the computing units, the CPU caches, and the translation lookaside buffer (TLB). Where multiprocessing systems include multiple complete processing units in one or more cores, multithreading aims to increase utilization of a single core by using thread-level parallelism, as well as instruction-level parallelism. As the two techniques are complementary, they are combined in nearly all modern systems architectures with multiple multithreading CPUs and with CPUs with multiple multithreading cores. Overview The multithreading paradigm has become more popular as efforts to further exploit instruction-level p ...
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Barrel Processor
A barrel processor is a CPU that switches between threads of execution on every cycle. This CPU design technique is also known as "interleaved" or "fine-grained" temporal multithreading. Unlike simultaneous multithreading in modern superscalar architectures, it generally does not allow execution of multiple instructions in one cycle. Like preemptive multitasking, each thread of execution is assigned its own program counter and other hardware registers (each thread's architectural state). A barrel processor can guarantee that each thread will execute one instruction every ''n'' cycles, unlike a preemptive multitasking machine, that typically runs one thread of execution for tens of millions of cycles, while all other threads wait their turn. A technique called C-slowing can automatically generate a corresponding barrel processor design from a single-tasking processor design. An ''n''-way barrel processor generated this way acts much like ''n'' separate multiprocessing cop ...
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Very Long Instruction Word
Very long instruction word (VLIW) refers to instruction set architectures designed to exploit instruction level parallelism (ILP). Whereas conventional central processing units (CPU, processor) mostly allow programs to specify instructions to execute in sequence only, a VLIW processor allows programs to explicitly specify instructions to execute in parallel. This design is intended to allow higher performance without the complexity inherent in some other designs. Overview The traditional means to improve performance in processors include dividing instructions into substeps so the instructions can be executed partly at the same time (termed ''pipelining''), dispatching individual instructions to be executed independently, in different parts of the processor (''superscalar architectures''), and even executing instructions in an order different from the program (''out-of-order execution''). These methods all complicate hardware (larger circuits, higher cost and energy use) because ...
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Fairbanks, Alaska
Fairbanks is a home rule city and the borough seat of the Fairbanks North Star Borough in the U.S. state of Alaska. Fairbanks is the largest city in the Interior region of Alaska and the second largest in the state. The 2020 Census put the population of the city proper at 32,515, and the population of the Fairbanks North Star Borough at 95,655 making it the second most populous metropolitan area in Alaska after Anchorage. The Metropolitan Statistical Area encompasses all of the Fairbanks North Star Borough and is the northernmost Metropolitan Statistical Area in the United States, located by road ( by air) south of the Arctic Circle. Fairbanks is home to the University of Alaska Fairbanks, the founding campus of the University of Alaska system. History Native American presence Athabascan peoples have used the area for thousands of years, although there is no known permanent Alaska Native settlement at the site of Fairbanks. An archaeological site excavated on ...
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MTA ISA
MTA may refer to: Organizations Transportation * Metropolitan Transportation Authority, the public transport agency in the metropolitan area of New York City, United States * Metropolitan Transit Authority (other), which may refer to several public transport agencies in other American cities * Flint Mass Transportation Authority, Genesee County, Michigan * Maine Turnpike Authority, Maine * Manchester Transit Authority, New Hampshire * Maryland Transit Administration * Massachusetts Bay Transportation Authority, formerly Metropolitan Transit Authority * Massachusetts Turnpike Authority * Mendocino Transit Authority, California * Mountain Ash railway station, Wales, National Rail station code * Nashville Metropolitan Transit Authority, Tennessee * San Francisco Municipal Transportation Agency, California *Los Angeles County Metropolitan Transportation Authority * Mersin-Tarsus-Adana Railway, a defunct Ottoman railway company Education * Hungarian Academy of Sciences (' ...
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Socket 940
Socket 940 is a 940-pin socket for 64-bit AMD Opteron server processors and AMD Athlon 64 FX consumer processors. This socket is entirely square in shape and pins are arranged in a grid with the exception of four key pins used to align the processor and the corners. AMD's Opteron and the older AMD Athlon 64 FX (FX-51) use Socket 940. Technical specifications Microprocessors designed for this socket were intended to be used in a server platform, and as such provide additional features to provide additional robustness. One such feature is the acceptance of only registered memory. While the more recent 940-pin socket AM2 is visually similar to this one, the two are electrically incompatible due to the integrated memory controller. Socket 940 CPUs integrate a DDR controller, whereas AM2 models use a DDR2 controller. See also *List of AMD microprocessors This article gives a list of AMD microprocessors, sorted by generation and release year. If applicable and openly known, the desi ...
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Remote Procedure Call
In distributed computing, a remote procedure call (RPC) is when a computer program causes a procedure (subroutine) to execute in a different address space (commonly on another computer on a shared network), which is coded as if it were a normal (local) procedure call, without the programmer explicitly coding the details for the remote interaction. That is, the programmer writes essentially the same code whether the subroutine is local to the executing program, or remote. This is a form of client–server interaction (caller is client, executor is server), typically implemented via a request–response message-passing system. In the object-oriented programming paradigm, RPCs are represented by remote method invocation (RMI). The RPC model implies a level of location transparency, namely that calling procedures are largely the same whether they are local or remote, but usually, they are not identical, so local calls can be distinguished from remote calls. Remote calls are usually orde ...
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