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NEC SX-6
The SX-6 is a NEC SX supercomputer built by NEC Corporation that debuted in 2001; the SX-6 was sold under license by Cray Inc. in the U.S. Each SX-6 single-node system contains up to eight vector processors, which share up to 64 GB of computer memory. The SX-6 processor is a single chip implementation containing a vector processor unit and a scalar processor fabricated in a 0.15 μm CMOS process with copper interconnects, whereas the SX-5 was a multi-chip implementation. The Earth Simulator is based on the SX-6 architecture. The vector processor is made up of eight vector pipeline units each with seventy-two 256-word vector registers. The vector unit performs add/shift, multiply, divide and logical operations. The scalar unit is 64 bits wide and contains a 64 KB cache. The scalar unit can decode, issue and complete four instructions per clock cycle. Branch prediction and speculative execution is supported. A multi-node system is configured by interconnecting up to 128 single-node s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth Simulator PB111943
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surface is made up of the ocean, dwarfing Earth's polar ice, lakes, and rivers. The remaining 29% of Earth's surface is land, consisting of continents and islands. Earth's surface layer is formed of several slowly moving tectonic plates, which interact to produce mountain ranges, volcanoes, and earthquakes. Earth's liquid outer core generates the magnetic field that shapes the magnetosphere of the Earth, deflecting destructive solar winds. The atmosphere of the Earth consists mostly of nitrogen and oxygen. Greenhouse gases in the atmosphere like carbon dioxide (CO2) trap a part of the energy from the Sun close to the surface. Water vapor is widely present in the atmosphere and forms clouds that cover most of the planet. More sola ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speculative Execution
Speculative execution is an optimization technique where a computer system performs some task that may not be needed. Work is done before it is known whether it is actually needed, so as to prevent a delay that would have to be incurred by doing the work after it is known that it is needed. If it turns out the work was not needed after all, most changes made by the work are reverted and the results are ignored. The objective is to provide more concurrency if extra resources are available. This approach is employed in a variety of areas, including branch prediction in pipelined processors, value prediction for exploiting value locality, prefetching memory and files, and optimistic concurrency control in database systems.Lazy and Speculative Execution |
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