click links in text for more info
SUMMARY / RELATED TOPICS

Complex instruction set computer

A complex instruction set computer is a computer in which single instructions can execute several low-level operations or are capable of multi-step operations or addressing modes within single instructions. The term was retroactively coined in contrast to reduced instruction set computer and has therefore become something of an umbrella term for everything, not RISC, from large and complex mainframe computers to simplistic microcontrollers where memory load and store operations are not separated from arithmetic instructions. A modern RISC processor can therefore be much more complex than, say, a modern microcontroller using a CISC-labeled instruction set in the complexity of its electronic circuits, but in the number of instructions or the complexity of their encoding patterns; the only typical differentiating characteristic is that most RISC designs use uniform instruction length for all instructions, employ separate load/store-instructions. Examples of instruction set architectures that have been retroactively labeled CISC are System/360 through z/Architecture, the PDP-11 and VAX architectures, Data General Nova and many others.

Well known microprocessors and microcontrollers that have been labeled CISC in many academic publications include the Motorola 6800, 6809 and 68000-families. Some designs have been regarded as borderline cases by some writers. For instance, the Microchip Technology PIC has been labeled RISC in CISC in others; the 6502 and 6809 have both been described as "RISC-like", although they have complex addressing modes as well as arithmetic instructions that operate on memory, contrary to the RISC-principles. Before the RISC philosophy became prominent, many computer architects tried to bridge the so-called semantic gap, i.e. to design instruction sets that directly support high-level programming constructs such as procedure calls, loop control, complex addressing modes, allowing data structure and array accesses to be combined into single instructions. Instructions are typically encoded in order to further enhance the code density; the compact nature of such instruction sets results in smaller program sizes and fewer main memory accesses, which at the time resulted in a tremendous saving on the cost of computer memory and disc storage, as well as faster execution.

It meant good programming productivity in assembly language, as high level languages such as Fortran or Algol were not always available or appropriate. Indeed, microprocessors in this category are sometimes still programmed in assembly language for certain types of critical applications. In the 1970s, analysis of high-level languages indicated some complex machine language implementations and it was determined that new instructions could improve performance; some instructions were added that were never intended to be used in assembly language but fit well with compiled high-level languages. Compilers were updated to take advantage of these instructions; the benefits of semantically rich instructions with compact encodings can be seen in modern processors as well in the high-performance segment where caches are a central component. This is because these fast, but complex and expensive, memories are inherently limited in size, making compact code beneficial. Of course, the fundamental reason they are needed is that main memories remain slow compared to a CPU core.

While many designs achieved the aim of higher throughput at lower cost and allowed high-level language constructs to be expressed by fewer instructions, it was observed that this was not always the case. For instance, low-end versions of complex architectures could lead to situations where it was possible to improve performance by not using a complex instruction, but instead using a sequence of simpler instructions. One reason for this was that architects sometimes "over-designed" assembly language instructions, including features which could not be implemented efficiently on the basic hardware available. There could, for instance, be "side effects", such as the setting of a register or memory location, seldom used. In balanced high-performance designs encoded and high-level instructions could be complicated to decode and execute efficiently within a limited transistor budget; such architectures therefore required a great deal of work on the part of the processor designer in cases where a simpler, but slower, solution based on decode tables and/or microcode sequencing is not appropriate.

At a time when transistors and other components were a limited resource, this left fewer components and less opportunity for other types of performance optimizations. The circuitry that performs the actions defined by the microcode in many CISC processors is, in itself, a processor which in many ways is reminiscent in structure to early CPU designs. In the early 1970s, this gave rise to ideas to return to simpler processor designs in order to make it more feasible to cope without ROM tables and/or PLA structures for sequencing and/or decoding; the first RISC

Nanomesh

The nanomesh is a inorganic nanostructured two-dimensional material, similar to graphene. It was discovered in 2003 at the University of Switzerland, it consists of a single layer of boron and nitrogen atoms, which forms by self-assembly into a regular mesh after high-temperature exposure of a clean rhodium or ruthenium surface to borazine under ultra-high vacuum. The nanomesh looks; the distance between two pore centers is only 3.2 nm, whereas each pore has a diameter of about 2 nm and is 0.05 nm deep. The lowest regions bind to the underlying metal, while the wires are only bound to the surface through strong cohesive forces within the layer itself; the boron nitride nanomesh is not only stable under vacuum and some liquids, but up to temperatures of 796oC. In addition it shows the extraordinary ability to trap molecules and metallic clusters, which have similar sizes to the nanomesh pores, forming a well-ordered array; these characteristics promise interesting applications of the nanomesh in areas like nanocatalysis, surface functionalisation, quantum computing and data storage media like hard drives.

H-BN nanomesh is a single sheet of hexagonal boron nitride, which forms on substrates like rhodium Rh or ruthenium Ru crystals by a self-assembly process. The unit cell of the h-BN nanomesh consists of 13x13 BN or 12x12 Rh atoms with a lattice constant of 3.2 nm. In a cross-section it means that nitrogen atoms are sitting on 12 rhodium atoms; this implies a modification of the relative positions of each BN towards the substrate atoms within a unit cell, where some bonds are more attractive or repulsive than other, what induces the corrugation of the nanomesh. The nanomesh corrugation amplitude of 0.05 nm causes a strong effect on the electronic structure, where two distinct BN regions are observed. They are recognized in the lower right image, a scanning tunneling microscopy measurement, as well as in the lower left image representing a theoretical calculation of the same area. A bounded region assigned to the pores is visible in blue in the left image below and a weakly bound region assigned to the wires appears yellow-red in the left image below.

See for more details. The nanomesh is stable under a wide range of environments like air and electrolytes among others, it is temperature resistant since it does not decompose in temperatures up to 1275K under a vacuum. In addition to these exceptional stabilities, the nanomesh shows the extraordinary ability to act as a scaffold for metallic nanoclusters and to trap molecules forming a well-ordered array. In the case of gold, its evaporation on the nanomesh leads to formation of well-defined round Au nanoparticles, which are centered at the nanomesh pores; the STM figure on the right shows Naphthalocyanine molecules, which were vapor-deposited onto the nanomesh. These planar molecules have a diameter of about 2 nm, whose size is comparable to that of the nanomesh pores, it is spectacularly visible how the molecules form a well-ordered array with the periodicity of the nanomesh. The lower inset shows a region of this substrate with higher resolution, where individual molecules are trapped inside the pores.

In addition, the molecules seem to keep their native conformation, what means that their functionality is kept, nowadays a challenge in nanoscience. Such systems with wide spacing between individual molecules/clusters and negligible intermolecular interactions might be interesting for applications such as molecular electronics and memory elements, in photochemistry or in optical devices. See for more detailed information. Well-ordered nanomeshes are grown by thermal decomposition of borazine 3, a colorless substance, liquid at room temperature; the nanomesh results after exposing the atomically clean Rh or Ru surface to borazine by chemical vapor deposition. The substrate is kept at a temperature of 796 °C when borazine is introduced in the vacuum chamber at a dose of about 40 L. A typical borazine vapor pressure inside the ultrahigh vacuum chamber during the exposure is 3x10−7 mbar. After cooling down to room temperature, the regular mesh structure is observed using different experimental techniques.

Scanning tunneling microscopy gives a direct look on the local real space structure of the nanomesh, while low energy electron diffraction gives information about the surface structures ordered over the whole sample. Ultraviolet photoelectron spectroscopy gives information about the electronic states in the outermost atomic layers of a sample, i.e. electronic information of the top substrate layers and the nanomesh. CVD of borazine on other substrates has not led so far to the formation of a corrugated nanomesh. A flat BN layer is observed on nickel and palladium, whereas stripped structures appear on molybdenum instead. Http://www.nanomesh.ch http://www.nanomesh.org

Yadadri Thermal Power Plant

Yadadri Thermal Power Plant or Yadadri TPS is an upcoming 4000 megawatt, supercritical thermal power project coming up at Dameracherla, Nalgonda district in Telangana, India. The project is second largest in South India, at a cost of ₹25,099 crores and is expected to complete by October 2021 in a phased manner; the state-owned Telangana State Power Generation Corporation Limited is building the 5 x 800 mega thermal power station, built on 2800 acres near Veerlapalem Village in Nalgonda District, the second mega project announced by the Telangana government after Bhadradri Thermal Power Plant. Chief Minister of Telangana, K. Chandrashekar Rao laid the foundation stone for the project on 8 June 2015 at Veerlapalem village, Dhamacherla mandal; the name was rechristened from Damaracharla Thermal Power Plant as Yadadri. The BHEL order, the largest in India for the company, includes design, supply and commissioning of project on EPC basis; the project completion is executed on fast track basis within 36 months for first two units and balance three units in 48 months from October 2017.

This is the biggest project executed by BHEL. The project has been accorded environmental clearance by the Ministry of Environment and Climate Change in June 2017 and yet to get water allocation from Krishna river. MoEF granted Environment clearance to this thermal power plant on June 29, 2017. LOI issued to BHEL with zero date 17 October 2017; the revised environment norms at the center, the 4000 MW project will cost Telangana an additional ₹3100 crore. The new environment norms mandate setting-up of flue-gas desulfurization devices; the planned capacity of the thermal power plant is 4000 MW

Ellesmere Port Gunners

Ellesmere Port Gunners were an English speedway team in Ellesmere Port, which operated at the Ellesmere Port Stadium from 1972 until their closure in 1985. The team operated from 1972 until 1982 continuously; the club went on to win the National League Championship. The speedway track was replaced by a greyhound racing track in late 1987; the first track record on the 424 yard track was 76.0 seconds, set by John Jackson on 2 May 1972. The eventual track record went twice on the same night during the Knock-Out Cup Final 1st-leg in 1985. Gordon Kennett of Eastbourne Eagles clocked 69.2 only to be beaten by The Gunners Louis Carr in the next heat with a time of 69.1. Riders from the 1970s included Paul Tyrer, Robbie Gardener, Wayne Hughes, Colin Goad, Barry Booth, Graham Drury, John Jackson, Gerald Smitherman, Geoff Pusey, Steve Finch, Chris Turner, Ian Gills, Roger Austin, Duncan Meredeth, Steve Taylor, Steve Casey, Nigel Wasley, Chris Morton, Louis Carr, Peter Carr, Phil Collins, Neil Collins, Eric Monahan, Pete Ellams, Paul Embley, Robert Craven, as well as Paul O'Neil from New Zealand and Cliff Anderson from Australia, A rider died on the Ellesmere Port track on 3 December 1977.

Stuart Shirley lost his life on a Saturday morning training school after a collision with Kenny Carter

1948 Republican Party vice presidential candidate selection

This article lists those who were potential candidates for the Republican nomination for Vice President of the United States in the 1948 election. After New York Governor Thomas Dewey secured the Republican presidential nomination on the third ballot of the 1948 Republican National Convention, the convention needed to choose Dewey's running mate. Dewey and several party leaders discussed Dewey's running mate during the evening of June 24. House Majority Leader Charles A. Halleck and former Minnesota Governor Harold Stassen were both considered, but Dewey decided to ask California Governor Earl Warren to serve as his running mate. Warren had earlier said that he would not accept the position, asked for time to consider the offer. In the meantime, Stassen was asked to serve as running mate. However, Dewey convinced the reluctant Warren to join his ticket. Halleck alleged that he had been promised the vice presidency in exchange for supporting Dewey, but Halleck's isolationism convinced Dewey and others to pass him over.

The Dewey-Warren ticket was well-received by the press, as it combined the youthful, popular governors of two of the three most populous states in the nation. Despite being favored by most, the Dewey-Warren ticket lost the 1948 election to the Democratic Harry S. Truman-Alben W. Barkley ticket. In 1953, Warren was appointed Chief Justice of the United States by President Dwight D. Eisenhower. California Governor Earl Warren Former Minnesota Governor Harold Stassen Ohio Senator and 1944 vice presidential nominee John Bricker House Majority Leader Charles A. Halleck of Indiana Illinois Governor Dwight Green 1948 Republican National Convention

Ptahmose (treasurer)

Ptahmose was Overseer of the seals under Amenhotep III, during the 18th Dynasty of Egypt. He officiated at the end of the reign of Amenhotep III and was the successor of Meryre in his office. Ptahmose is attested only by a dark granite statue from Thebes, dedicated to him by his son Hj and now in Florence, by an inscription on a vessel from Malkata; this inscription proves that he was treasurer at the time of the first Sed festival of Amenhotep III. The location of Ptahmose's tomb is unknown. Arielle P. Kozloff, Betsy M. Bryan, Lawrence M. Berman: Egypt's Dazzling Sun. Amenhotep III and his World. Cleveland Museum of Art, Cleveland 1992, ISBN 0-940717-17-4, p. 52