AcharyaChanakya/simple-wikipedia huggingface dataset:
Goulburn has a railway station on the Main Southern railway line. It is a service centre for the many farms in the area. It also provides a rest stop for those travelling on the Hume Highway. It has a central park and many historic buildings, including old houses near the railway station on Sloane Street. It also has two 19th-century cathedrals. It is home to the "Big Merino", the world's largest cement sheep.
Women's suffrage
Women's suffrage is the right of women to vote and to be elected to an office. The right has generally been given after long political campaigns. In many countries, it was recognised before universal suffrage. Before the late 19th century, a very few countries allowed women to vote in political elections.
The modern movement for women to gain the right to vote started in France in the late-18th century. The French Republic had been founded after a revolution, and political scientist Antoine Condorcet and activist Olympe de Gouges campaigned for women to be allowed to vote in the national election.
In early cases of women's suffrage, only those women who met certain requirements were given the right to vote in certain kinds of elections. In Sweden, there was conditional women's suffrage during the Age of Liberty (1718–1771). Unmarried women who owned property could vote in New Jersey from 1776 to 1807. In the 1792 election in Sierra Leone, all heads of household—one-third of whom were women—could vote.
Several British colonies recognised women's suffrage before most countries. The female descendants of the "Bounty" mutineers who lived on Pitcairn Islands could vote from 1838. This right was kept when they were resettled on Norfolk Island in 1856. Women in South Australia allowed to vote in local elections from 1861, and those on the Isle of Man could vote in parliamentary elections from 1881. In 1893, New Zealand became the first independent country to give all adult women the right to vote in national elections. The women in South Australia got the same right in 1894, and became the first to get the right to stand (run) for seats in parliament.
Many countries did the same soon after, following similar battles. Limited voting rights were also gained by women in several Western countries in the late 19th century, including Sweden, Finland and the United Kingdom. Russian Empire was the first European country to introduce women's suffrage, in 1906. It also elected the world's first female members of parliament in its 1907 elections. At that time it was a part of the Russian Empire. In the years before World War I, women in Norway (1913) and Denmark (1915) also won the right to vote, as did women in the other Australian states. In most other Western countries, women's suffrage came at the end of World War I.
Ceylon, now called Sri Lanka, recognised the right in 1931. It elected the world's first female head of government, Sirimavo Bandaranaike, in the country's 1960 elections. Women's suffrage was explicitly recognised as a right by the United Nations in 1979.
Grenfell, New South Wales
Grenfell is a country town in the central west of New South Wales, Australia. It is in the Weddin Shire. It is west of Sydney. It is close to Forbes, Cowra and Young. In 2006 there were 1,994 people living in Grenfell.
The Grenfell area was the home of the Wiradjuri Aborigines. Europeans first settled when gold was found at Emu Creek. The town was renamed after John Grenfell, the Gold Commissioner at Forbes. He had been killed in 1866 when bushrangers attacked a stagecoach on which he was travelling.
By 1870-71 more gold was found at Grenfell than in any other town in NSW. By the middle of the 1870s the gold was running out. Wheat was first grown in the area in 1871. The railway reached Grenfell in 1901.
The Grenfell area has been badly affected by drought since 2001.
The poet and story writer Henry Lawson was born on the gold fields at Grenfell. On the Queen's Birthday weekend in June every year, the town has "The Henry Lawson Festival of Arts". Thousands of people come from all over Australia for the art, poetry and writing competitions. Over the years, famous visitors have included Chips Rafferty, Barry Humphries, Patrick White and Sigrid Thornton.
In June 2007, the "Spirit of the Bush Concert" was held. It was organized by Australian of the Year, Lee Kernaghan, local and international star Steve Forde and the Flange, Adam Brand, Leo Sayer, Diesel, and The McClymonts.
Cricketer Stan McCabe, cyclist Reggie "IronMan" McNamara and tennis player Jan Lehane and Creative Writer Adam Burn were born in Grenfell.
Mike Vernon
Michael "Mike" Vernon (born 24 February 1963 in Calgary, Alberta, Canada) is a Canadian retired professional ice hockey player. For 21-years he played in the National Hockey League, he played as a goaltender for the Calgary Flames, Detroit Red Wings, San Jose Sharks and the Florida Panthers. He won the Stanley Cup twice as a member of the Flames in 1989 and then again in 1997 with the Red Wings, where he also won the Conn Smythe Trophy as playoff MVP. In 2002 he retired and he currently works as a Special Assistant to the Vice President of Hockey Operations for the Tampa Bay Lightning.
Mike Vernon holds the following Calgary Flames franchise records:
1997 United Kingdom general election
The UK general election, 1997 was an election held on 1 May 1997 to elect 659 members to the House of Commons of the United Kingdom. The three main candidates to become Prime Minister are shown to the right:
The Labour Party and its leader Tony Blair gained the majority of seats and created the first Labour government since 1979. The Labour Party won 418 seats which was the highest majority of seats for any party since the Conservatives in the 1931 General Election. The Conservative Party suffered it's lowest number of seats since 1906 and lost all of its seats in Scotland and Wales. Several prominent Conservative politicians lost their seats such as Defence Secretary Michael Portillo, Foreign Secretary Malcolm Rifkind, Scottish Secretary Michael Forsyth as well as Edwina Currie, David Mellor and Ian Lang.
The Liberal Democrats won 46 seats, which was the highest number of seats for a third party since 1929. The Referendum Party ran on the single issue of taking Britain out of the European Union and won 2.6% of the vote but no seats.
The final results of the election were:
Metropolitan France
Metropolitan France ( or "la Métropole") is the part of France that is in Europe. It can also be described as mainland France plus the island of Corsica. By contrast, Overseas France ("France d'outre-mer") is the collective name for all of the French overseas departments, territories and collectivities and New Caledonia. Metropolitan France and Overseas France together form the French Republic.
Metropolitan France covers an area of 551,695 km² (213,011 sq. miles). Excluding the territory of Adélie Land in Antarctica, this is 81.8% of the nation's territory. As of January 1, 2011, 63,136,180 people lived in metropolitan France. This is 95.9% of the nation's population.
The five overseas departments – Martinique, Guadeloupe, Réunion, French Guiana, and Mayotte – have the same political status as the departments in metropolitan France. Metropolitan France and these five overseas departments together are sometimes called "France entière" ("entire France") by the French administration, especially by INSEE. This grouping does not include the French overseas collectivities and territories, which have more autonomy than the overseas departments.
Overseas France
Overseas France () is the part of France that is outside of the European continent. It consists of all overseas departments, territories and collectivities. These territories have several different legal statuses and levels of autonomy. Overseas France includes island territories in the Atlantic, Pacific and Indian oceans, French Guiana in South America, and Adélie Land in Antarctica. Each inhabited territory is represented in both the French National Assembly and the French Senate (which together make up the Parliament of France).
2,685,705 people lived in the overseas departments and territories in January 2011.
Overseas departments and regions are completely part of France.
The category of "overseas collectivity" was created by changes made to France's constitution in 28 March 2003. Each overseas collectivity has its own written laws.
The overseas departments and territories are represented by 27 "députés" in the French National Assembly and 21 senators in the French Senate. This is 4.7% of the 577 "députés" and 6% of the 343 senators.
The 11 French Overseas Territories are :
Lands generally uninhabited, except by researchers in scientific stations.
Justin Raimondo
Justin Raimondo (born Dennis Raimondo; November 18, 1951 – June 27, 2019) was an American writer and the editorial director of the website Antiwar.com. He was born in White Plains, New York.
Raimondo died on June 27, 2019 in Sebastopol, California from lung cancer at the age of 67.
Group (mathematics)
In mathematics, a group is a kind of algebraic structure. A group is a set with an operation. The group's operation shows how to replace any two elements of the group's set with a third element from the set in a useful way. A familiar example of a group is the set of integers with the addition operation.
Instead of "an element of the group's set", mathematicians usually save words by saying "an element of the group".
Mathematicians use capital letters to stand for groups. They often use "G", "H", or "K".
They also use lower-case letters to stand for group elements. For example, they would say ""a" is in "G"" to mean ""a" is an element of "G"".
They write group operations with symbols like • or *, or by writing two elements next to each other. So ""a" • "b"", ""a" * "b"", and ""ab"" can all mean "the element formed when the group's operation combines "a" and "b"".
Not every set and operation make a group. A group's set and operation must obey some special rules. These are called group axioms. The following list has each axiom in both words and mathematical symbols.
To name the group, one should say all three parts: ("G", •, "e"). But when it is clear, one may just say that "G" is a group.
It is possible to find that for two elements "a" and "b" in a group, "a" • "b" is different from "b" • "a". For example, maybe "a" • "b" = c, but "b" • "a" = d.
For some groups, however, "a" • "b" = "b" • "a" for every "a" and "b" in the group. These special groups have a special name. They are called Abelian groups and their operation is said to be commutative"."
The number of elements in a group is called the group's "order".
One everyday example of a group is the set of whole numbers (integers) with the addition operation. It is easy to see that when adding two integers, the result is always an integer. So closure is true. The identity element for this group is zero. Because the order of additions does not matter (in other words, formula_1), associativity rule is also true. And the inverse of any integer is its opposite number (the inverse element of zero is zero). This group is also an abelian group. It is an infinite group (also called a group of "infinite order") because it has an infinite number of elements: all the integers.
The set of integers with the multiplication operation is not a group, because with multiplication, most integers have no inverse that is also an integer (closure rule is not always obeyed).
Another important kind of groups are groups of symmetries. Symmetry groups provide many examples of groups. It can be proved that every group of finite order is a group of symmetries. For this reason, group theory is called the mathematical study of symmetry.
Objects are symmetric if keep some interesting features when changed. Those changes of objects (of any kind) are called symmetries.
Sets have only elements in them so they are one of the simplest objects to think of. Symmetries of a set are one-to-one functions that shuffle the elements of this set. Those functions change elements one with other but for example keep their amount the same as before shuffling.
When such group is finite (has finite order), say it has "n" elements, one can think of this group as the set of those shuffles (one-to-one functions) of "n" elements. The symmetric group given on "n" elements is often written as formula_2.
Shuffles can be combined one after another—function composition is the "operation" of this group.
Because making shuffling after shuffling is yet another shuffling, that means that there is "closure".
Also three shuffles can be combined in any of two ways: first two in the beginning to give a shuffle to combine with a third one, or last two in the beginning to give a shuffle to be combined with the first one ("associavity").
The "identity element" is the shuffle in which nothing changes.
Any shuffle can be undone by reversing the change. That reverse is the "inverse element".
Because order of shuffling matters—it is important which of the shuffles go first—group of symmetries are almost never abelian.
Think of a square and (one-to-one) functions can that shuffle the place of points of the square but keep the square as a whole in one place. Interesting features are size and place of the square. Such symmetries are called (global) isometries (see congruence).
Here are all of the isometries of a square: turn the square clockwise 90, 180, or 270; turn the square counter-clockwise 90, 180, or 270; reflect the image of the square in a vertical mirror, or in a horizontal mirror, or a diagonal mirror to the right or the left; or leave the square as it was.
This is a "finite" group, or a group of (finite) order 8, because there are 8 different isometries in total. It is a non-abelian group because it makes a difference which order when making a turn and a reflection.
This is not only kind of symmetry for this square. When position is not an interesting feature then there are many more symmetries. Then infinitely many moves are allowed. If the shape of a square is all that matters then there is even more symmetries of this square, those are similarities.
This shows that it is important to say what one exactly mean by ‘symmetry’. What are interesting features of objects that keep the same during a change.
Idea to study geometry by studying symmetries of figures goes back to XIX century. It is how mathematicians think of geometry today. They even use those methods when studying different objects and speak about ‘geometry’ and ‘symmetries’ of strange objects.
Many things in mathematics are groups. This is mostly because groups help to benefit from a brilliant idea of ‘a change that keeps interesting feature unchanged’. For example, equations. The ways of solving equations can be a group. Physical things can be studied as groups. There are important symmetries about physical things which are groups (this can be place, turn, time, energy, electric charge).
Sometimes, part of the group is also a group. In that case, the part is called a "subgroup". For example, there is this subgroup of the group of isometries of a square: only the turns of the square and the identity (not the reflections in a mirror). Many useful things can be proved about groups and their subgroups.
Chelsea Victoria Clinton (born February 27, 1980) is the only child of Bill Clinton, former President of the United States, and his wife, former Secretary of State, Hillary Clinton.
Clinton was born at Baptist Health Medical Center in Little Rock, Arkansas. She moved in to The White House when she was twelve years old when her father, Bill Clinton, became president. She has helped her mother, Hillary Clinton, many times by campaigning for people to elect her mother as the first woman President of the United States.
Clinton has a Bachelor of Arts in History. She also has a Master of Philosophy qualification. She went to university at Oxford University and Stanford University.
Clinton is vegetarian.
On November 30, 2009, it was announced that Clinton was engaged to Marc Mezvinsky, an investment banker. They married on July 31, 2010. On November 14, 2011, Clinton announced joining as a "special correspondent" for NBC News. She will continue as a PhD student.
On September 2014, Clinton gave birth to a daughter Charlotte. She was gave birth to a eldest son Aiden on June 2016.
Her youngest son, Jasper, was born in New York on July 2019.
Crich
Crich ( "kryech") is a village in the English county of Derbyshire. It is the home of the National Tramway Museum in the Crich Tramway Village.
At the top of Crich Hill is a tower. The tower was built to remember members of the regiment who died in battle, particularly in World War I.
The tower was built in 1923 on the site of an older tower called Crich Stand. The Memorial Tower is the end of an annual pilgrimage on the first Sunday in July. It is above sea level. The tower has 52 steps to the top. From the top of the tower, eight counties and landmarks such as the Humber Bridge and Lincoln Cathedral can be seen.
Crich is mentioned in 1009 by Ethelred the Unready when he gives away Weston-on-Trent to his minister.
A workhouse opened in 1734 and had 40 people. The workhouse accepted poor people from places, including Melbourne, Pentrich, Willington, Mercaston and Denby.
The television series "Peak Practice" and the 2007 movie ""And When Did You Last See Your Father"" were filmed in Crich.
Edwardian period
The Edwardian era in the United Kingdom is the period which included the reign of King Edward VII (1901–1910). The "Edwardian era" usually includes some years before and after his reign, up to the First World War.
King Edward VII was very different from Queen Victoria. Victoria had become almost a recluse after her husband died. On the other hand, Edward was an important leader. Edward and his fashionable friends followed the art and fashions of other European countries. Edward enjoyed travelling, and his visits to Paris improved relations between the two countries.
The United Kingdom was a powerful nation in the nineteenth century. There was progress in British science and industry at this time. The British Empire was large. The Royal Navy was the most powerful navy in the world at that time.
The prosperity of the Edwardian era was built on trade and manufacturing. These were the main industries at the time:
The extent of this trade was big. Railways all over the world were built by the British. They were equipped with machinery made in Britain. Germany also became a powerful nation, and the United States was already becoming an industrial giant. By Edward VII's time. Both of these countries were as industrially advanced.
Most British people in the "Edwardian era" were sure that British progress would continue. They were certain that the United Kingdom would continue to be very powerful. The era came to an unexpected end with the First World War. Economically and in human terms, this was a disaster for most of the European nations.
There was a lot of inequality in society in the United Kingdom in the Edwardian era, as there always had been. Rich people and poor people had very different living standards at this time.
Most adult men could vote, but women could not. Suffragettes were fighting for the right to vote.
Objectivity (philosophy)
Objectivity is a philosophical opinion or method that believes that reality exists outside of the human mind. People can separate their own ideas and opinions from the observations they make. Objective observations are true no matter who makes the observation. Being objective helps people focus on things that everyone can agree on.
The Scientific method claims objectivity but see epistemology, the philosophy of science and the work of Karl Popper. The opposite of objectivity is subjectivity.
Rod Paige
Roderick Raynor "Rod" Paige (born June 17, 1933), served as the 7th United States Secretary of Education from 2001 to 2005. He was the first African American to serve as the nation's education chief. He earned a bachelor's degree from Jackson State University in Mississippi and a Master's degree and an Ed.D from Indiana University Bloomington. He also holds an honorary doctoral degree from the University of Houston presented to him in 2000.
Paige was sitting with George W. Bush at the Emma E. Booker Elementary School in Sarasota, Florida, when Bush received the news that a second plane had hit the World Trade Center in the September 11, 2001 attacks.
On November 15, 2004, Paige announced his resignation after overseeing the President's education agenda for four years. White House domestic policy adviser Margaret Spellings was nominated as his successor. The U.S. Senate confirmed her on January 20, 2005 after Bush's inauguration for a second term.
Joshua Bolten
Alan Stephenson Boyd
Alan Stephenson Boyd (July 20, 1922 – October 18, 2020) was an American politician and lawyer. He was the first United States Secretary of Transportation, appointed by Lyndon Johnson in November 1966.
He was appointed to the Civil Aeronautics Board in 1959 by Dwight Eisenhower and promoted to chairman by John F. Kennedy.
When the Richard M. Nixon administration took power, Boyd left the government and became the president of the Illinois Central Railroad, a position he held from 1969 to 1972.
Boyd died at a retirement home in Seattle, Washington on October 18, 2020 at the age of 98.
Mary Peters (politician)
President-elect
Flag of Australia
The flag of Australia is a national flag. In 1901, Australia became a single country, instead of six separate colonies. A competition was held to design a new flag for the new country. The winning flag has a blue background, the Union Jack, and six stars. Five stars are in the shape of the constellation the Southern Cross, the other is the Commonwealth Star. The flag has been used from 1903, but did not become the official flag of Australia until 1953.
On 29 April 1901, some private companies with the support of the Australian Government set up a competition to design a new flag for Australia. The prize money was ₤200 including ₤75 from a magazine and ₤50 from a tobacco company. There were 32,823 designs entered into the competition. These were put on show in Melbourne at the Royal Exhibition Building. The judges, from the army, navy, merchant navy, and pilot service, to choose the best flag were:
The judges took eight days to choose a winning flag.
Five flags were almost the same, and they shared first prize. The Prime Minister of Australia, Edmund Barton, announced the winners on 3 September 1901. The winners were:
The winning flag was flown from the top of the Exhibition Building. The Prime Minister Edmund Barton wrote to the Governor-General to get approval from the King for the new flag. This was officially announced on February 20, 1903.
Some of the winning flags had different numbers of points on the stars of the Southern Cross. This was simplified to seven points for the four largest stars and five for the small one. The Commonwealth Star had six points for the six states. This was the design in 1903. In 1912, an extra point was added to the Commonwealth Star for the Territories of Australia.
In 1934, the government published how the Australian flag should be made. The flag of the United Kingdom, the Union Jack was still the official flag in Australia until 1954. By law, only the Australian government was allowed to fly the blue Australian flag. Everyone else that wanted to use an Australian flag used the red one, called the Red Ensign. In 15 March 1941, the Prime Minister of Australia, Robert Menzies, gave permission for the blue flag to be used on public buildings, schools and by the public. Australian ships would use the Red Ensign.
In 1954, the Australian Flag became the official Australian National Flag. The Australian flag is the most important flag flown in Australia, and must be given more importance than flags from other countries. When it is raised or lowered people should face the flag and not talk. It should only be used properly, for example, it can not be used to cover a table or a seat, and it can not be allowed to touch the ground.
The Royal Australian Navy has had its own flag from 1 March 1967. This looks like the national flag but has a white background with blue stars, called the Australian White Ensign. The Royal Australian Air Force got its own flag in 1949. This was changed in 1981 to feature a red kangaroo.
The Queen of Australia has her own flag for use when she visits Australia. The Governor-General of Australia also has a flag which is flown from his or her official house and from his or her car.
2000 United States presidential election
The 2000 United States presidential election happened on November 7, 2000. The Republican candidate, George W. Bush, then-governor of Texas and son of former president George H. W. Bush, won the election. He defeated the Democratic candidate Al Gore, who was then-Vice President.
Incumbent Democratic President Bill Clinton was not eligible to serve a third term, and Vice President Gore was able to secure the Democratic nomination. Bush was seen as the early favorite for the Republican nomination, and despite a contentious primary battle with Senator John McCain and other candidates, secured the nomination by Super Tuesday. Many third-party candidates also ran, most prominently Ralph Nader. Bush chose former Secretary of Defense Dick Cheney as his running mate, and Gore chose Senator Joe Lieberman as his. Both candidates focused primarily on domestic issues, such as the budget, tax relief, and reforms for federal social insurance programs, though the foreign policy was not ignored. Clinton and Gore did not often campaign together, a deliberate decision resulting from the Lewinsky scandal two years prior.
Bush narrowly won the November 7 election, with 271 electoral votes to Gore's 266. There was a disagreement over who won Florida's 25 electoral votes because the way Florida voted was different from other states. A recount happened in the state and the uncommon event that the winner got fewer popular votes than the loser. The Court's decision in Bush v. Gore announced on December 12, 2000, this ended the recounts, effectively awarding Florida's votes to Bush and granting him the victory.
2004 United States presidential election
The 2004 United States presidential election happened on November 2, 2004. During that day the President of the United States and Vice President of the United States were elected. President George W. Bush won against Democratic Party candidate John Kerry, the junior U.S. Senator from Massachusetts. Foreign Policy was the biggest issue during the election mainly because of the War on Terrorism and the 2003 Invasion of Iraq.
Since the last presidential election, there were concerns about voting. The winner was not determined until the following day when Kerry decided not to dispute Bush's win in the state of Ohio. The state held enough electoral votes to determine the winner of the presidency. Both Kerry and Democratic National Committee Chairman Howard Dean have stated their opinion that voting in Ohio did not proceed fairly and that, had it done so, the Democratic ticket might have won that state and therefore the election.
Only three states changed which party to vote for. New Mexico and Iowa voted Democratic in 2000, but those states voted Republican in 2004. New Hampshire voted Republican in 2000 but the state voted Democratic in 2004. In the Electoral College, Bush received 286 electoral votes, and Kerry received 251 electoral votes. Kerry was supposed to have 252, but one electoral vote that was supposed to go for Kerry went for his running mate, John Edwards.
Register renaming
In computer engineering, register renaming refers to a technique used to avoid unnecessary serialized execution of program instructions because of the reuse of the same registers by those instructions.
Programs are composed of instructions which operate on values. The instructions must name these values in order to distinguish them from one another. A typical instruction might say, add X and Y and put the result in Z. In this instruction, X, Y, and Z are the names of storage locations.
In order to have a compact instruction encoding, most processor instruction sets have a small set of special locations which can be directly named. For example, the x86 instruction set architecture has 8 integer registers, x86-64 has 16, many RISCs have 32, and IA-64 has 128. In smaller processors, the names of these locations correspond directly to elements of a register file.
Different instructions may take different amounts of time (e.g., CISC architecture). For instance, a processor may be able to execute hundreds of instructions while a single load from main memory instruction is in progress. Shorter instructions executed while the load is outstanding will finish first, thus the instructions are finishing out of the original program order. Out-of-order execution has been used in most recent high-performance CPUs to achieve some of their speed gains.
Consider this sequance of instructions running on an out-of-order CPU:
Instructions 4, 5, and 6 are independent of instructions 1, 2, and 3, but the processor cannot finish 4 until 3 is done, because 3 would then write the wrong value.
We can remove this restriction by changing the names of some of the registers:
Now instructions 4, 5, and 6 can be executed in parallel with instructions 1, 2, and 3, so that the program can be executed faster.
When possible, compilers do this renaming. But compilers are limited by the number of register inside the CPU. Many high performance CPUs have more physical registers than may be named directly in the instruction set and they can rename registers in hardware to achieve better instruction level parallelism.
Anything that is read and written can be renamed. While the general-purpose and floating-point registers are the most, flag and status registers or even individual status bits are commonly renamed as well.
Memory locations can also be renamed, although it is not commonly done to the level used in register renaming.
When more than one instruction references a particular location for an operand, either reading it (as an input) or writing it (as an output), executing those instructions in an order different from the original program order can cause to three kinds of problems, also known as hazards:
Chesterfield is a market town and borough in the county of Derbyshire in the East Midlands of England. It is on the River Rother and the River Hipper. It is Derbyshire's largest town (Derby is a city).
It is a very old town and was founded between 70–100 AD. The town received its market charter from King John in 1204.
It is 24 miles (39 km) north of Derby and 11 miles (18 km) south of Sheffield.
The town is located on the A61 between Derby and Thirsk in North Yorkshire. It is 6 miles (9.7 km) from the M1.
A 2019 census estimated that the borough has around 104,900 residents.
Chesterfield's most famous landmark is Church of St Mary and All Saints. It is famous because of its "crooked spire". The town's football club, Chesterfield F.C., are nicknamed "The Spireites" due to this.
Chesterfield railway station is on the Midland Main Line. Passengers can get local trains to towns and villages around the East Midlands as well as long-distance trains, operated by East Midlands Railway, to London, Sheffield and Nottingham. CrossCountry trains also stop at Chesterfield, providing passengers with direct trains to Birmingham, the North East, Scotland and Cornwall.
Chesterfield is twinned with:
Formation and evolution of the Solar System
The formation and evolution of the Solar System describes how the Solar System began, and how it will go on changing. The accepted idea is that 4.6 billion years ago, there was a very big cloud of gas nearby our area of space, known as a nebula.
All things with mass come together, or gravitate towards one another. This pulled all the gas towards the center. Eventually the pressure at the center raised the temperature so that hydrogen atoms fused together to make helium. This began the star we know as the Sun. The process by which solar systems are created is called "the nebular theory".
The spin of the planets around the Sun, and each around its own axis, was first caused by the original gas cloud having different density in different places. The spin increased because of the contraction under gravity (conservation of energy). So did the flatness of the solar system's shape. As the collapse continues, conservation of angular momentum means that the rotation accelerated. This largely prevents the gas from directly sticking onto the central core. The gas is forced to spread outwards near its equatorial plane, forming a disk, which in turn sticks onto the core.
Gravity caused the atoms in the Sun to become very close to each other. All this energy eventually made our star: the Sun. The leftover gas mostly went to the gas giants—also known as Jovian planets.
Because of the Sun's huge mass (99.86% of the whole mass of the Solar System), it had very strong gravity. The centrifugal force of the planets going round the Sun balances the gravitational pull of the Sun. The huge density at its core causes a fusion reaction which turns hydrogen into helium with the radiation of heat, light and other forms of electromagnetic radiation.
Rock and dust makes the terrestrial planets, their moons, asteroids and all other objects in the Solar System. The gas giant planets also do have rocky or metallic centres. This is known from the data-gathering by satellites. This rocky material cannot come from the Sun, because the Sun is all hydrogen plus some helium.
The next issue is: "if the Sun turns hydrogen into helium, where do all the other elements come from?" There is only one possible answer: these higher elements came from earlier generations of stars. Huge supernovas which exploded billions of years ago in the neighbourhood of the young Solar System produced the higher elements. Huge stars run through their life cycle much faster than smaller stars. That is caused by the even higher pressures and temperatures inside them as compared with an average main sequence star like the Sun.
The nebular hypothesis, as it was called, was first worked out in the 18th century. Three men worked on it:
Swedenborg first had the idea, and Kant worked it up into a proper theory. In 1755 Kant published his "Universal natural history and theory of the heavens" (in German, of course). He argued that gaseous clouds, nebulae, slowly rotate, gradually collapse and flatten due to gravity. They eventually form stars and planets.
Meanwhile, a similar model was developed independently and proposed in 1796 by Laplace. in his "Exposition du systeme du monde". He thought that the Sun originally had an extended hot atmosphere throughout the volume of the Solar System. His theory had a contracting and cooling protosolar nebula. As this cooled and contracted, it flattened and spun more rapidly, throwing off (or shedding) a series of gaseous rings of material; and according to him, the planets condensed from this material. His model was similar to Kant's, except more detailed and on a smaller scale. Unfortunately, there was a problem with Laplace's version. The main problem was the angular momentum distribution between the Sun and planets. The planets have 99% of the angular momentum, and this fact could not be explained by the nebular model. It was quite a long time before this was understood.
The birth of the modern widely accepted theory of planetary formation – the solar nebular disk model (SNDM) – is due to the Soviet astronomer Victor Safronov. His book "Evolution of the protoplanetary cloud and formation of the Earth and the planets", translated to English in 1972, had a big effect. In this book almost all major problems of the planetary formation process were formulated and some of them solved. Safronov's ideas were further developed. There are still quite a few aspects of the Solar System which need to be explained.
Although it originally applied only to our own Solar System, the SNDM is now thought to be the usual way of star formation throughout the universe. As of August 2017, over 3000 extrasolar planets have been discovered in our galaxy.
The nebular hypothesis says that the Solar System formed from the gravitational collapse of a fragment of a giant molecular cloud. The cloud was about 20 parsec (65 light years) across, while the fragments were roughly 1 parsec (three and a quarter light-years) across.
Because of the conservation of angular momentum, the nebula spun faster as it collapsed. As the material within the nebula condensed, the atoms within it began to collide with increasing frequency, converting their kinetic energy into heat. The center, where most of the mass collected, became increasingly hotter than the surrounding disc. Over about 100,000 years, a hot, dense protostar began at the centre.
The oldest inclusions found in meteorites may be the first solid material to form in the presolar nebula. They are 4568.2 million years old. This is one definition of the age of the Solar System.
In computer engineering, microarchitecture (sometimes abbreviated to µarch or uarch) is a description of the electrical circuitry of a computer, central processing unit, or digital signal processor that is sufficient for completely describing the operation of the hardware.
Scholars use the term "computer organization" while people in the computer industry more often say, "microarchitecture". Microarchitecture and instruction set architecture (ISA), together, constitute the field of computer architecture.
Computers have been using microprogramming of control logic since the 1950s. The CPU decodes the instructions and sends signals down appropriate paths by means of transistor switches. The bits inside the microprogram words controlled the processor at the level of electrical signals.
The term: microarchitecture was used to describe the units that were controlled by the microprogram words, in contrast to the term: "architecture" that was visible and documented for programmers. While architecture usually had to be compatible between hardware generations, the underlying microarchitecture could be easily changed.
The microarchitecture is related to, but not the same as, the instruction set architecture. The instruction set architecture is near to the programming model of a processor as seen by an assembly language programmer or compiler writer, which includes the execution model, processor registers, memory address modes, address and data formats, etc. The microarchitecture (or computer organization) is mainly a lower level structure and therefore manage a large number of details that are hidden in the programming model. It describes the inside parts of the processor and how they work together in order to implement the architectural specification.
Microarchitectual elements may be everything from single logic gates, to registers, lookup tables, multiplexers, counters, etc., to complete ALUs, FPUs and even larger elements. The electronic circuitry level can, in turn, be subdivided into transistor-level details, such as which basic gate-building structures are used and what logic implementation types (static/dynamic, number of phases, etc.) are chosen, in addition to the actual logic design used built them.
A few important points:
A very simplified high level description — common in marketing — may show only fairly basic characteristics, such as bus-widths, along with various types of execution units and other large systems, such as branch prediction and cache memories, pictured as simple blocks — perhaps with some important attributes or characteristics noted. Some details regarding pipeline structure (like fetch, decode, assign, execute, write-back) may sometimes also be included.
The pipelined datapath is the most commonly used datapath design in microarchitecture today. This technique is used in most modern microprocessors, microcontrollers, and DSPs. The pipelined architecture allows multiple instructions to overlap in execution, much like an assembly line. The pipeline includes several different stages which are fundamental in microarchitecture designs. Some of these stages include instruction fetch, instruction decode, execute, and write back. Some architectures include other stages such as memory access. The design of pipelines is one of the central microarchitectural tasks.
Execution units are also essential to microarchitecture. Execution units include arithmetic logic units (ALU), floating point units (FPU), load/store units, and branch prediction. These units perform the operations or calculations of the processor. The choice of the number of execution units, their latency and throughput are important microarchitectural design tasks. The size, latency, throughput and connectivity of memories within the system are also microarchitectural decisions.
System-level design decisions such as whether or not to include peripherals, such as memory controllers, can be considered part of the microarchitectural design process. This includes decisions on the performance-level and connectivity of these peripherals.
Unlike architectural design, where a specific performance level is the main goal, microarchitectural design pays closer attention to other constraints. Attention must be paid to such issues as:
In general, all CPUs, single-chip microprocessors or multi-chip implementations run programs by performing the following steps:
Complicating this simple-looking series of steps is the fact that the memory hierarchy, which includes caching, main memory and non-volatile storage like hard disks, (where the program instructions and data are) has always been slower than the processor itself. Step (2) often introduces a delay (in CPU terms often called a "stall") while the data arrives over the computer bus. A big amount of research has been put into designs that avoid these delays as much as possible. Over the years, a central design goal was to execute more instructions in parallel, thus increasing the effective execution speed of a program. These efforts introduced complicated logic and circuit structures.
In the past such techniques could only be implemented on expensive mainframes or supercomputers due to the amount of circuitry needed for these techniques. As semiconductor manufacturing progressed, more and more of these techniques could be implemented on a single semiconductor chip.
What follows is a survey of micro-architectural techniques that are common in modern CPUs.
The choice of which Instruction Set Architecture to use greatly affects the complexity of implementing high performance devices. Over the years, computer designers did their best to simplify instruction sets, in order to enable higher performance implementations by saving designers effort and time for features which improve performance rather than wasting them on the complexity of instruction set.
Instruction set design has progressed from CISC, RISC, VLIW, EPIC types. Architectures that are dealing with data parallelism include SIMD and Vectors.
One of the first, and most powerful, techniques to improve performance is the use of the instruction pipeline. Early processor designs performed all of the steps above on one instruction before moving onto the next. Large portions of the processor circuitry were left idle at any one step; for instance, the instruction decoding circuitry would be idle during execution and so on.
Pipelines improve performance by allowing a number of instructions to work their way through the processor at the same time. In the same basic example, the processor would start to decode (step 1) a new instruction while the last one was waiting for results. This would allow up to four instructions to be "in flight" at one time, making the processor look four times as fast. Although any one instruction takes just as long to complete (there are still four steps) the CPU as a whole "retires" instructions much faster and can be run at a much higher clock speed.
Improvements in chip manufacturing allowed more circuitry to be placed on the same chip, and designers started looking for ways to use it. One of the most common ways was to add an ever-increasing amount of cache memory on-chip. Cache is a very fast memory, memory that can be accessed in a few cycles as compared to what is needed to talk to main memory. The CPU includes a cache controller which automates reading and writing from the cache, if the data is already in the cache it simply "appears," whereas if it is not the processor is "stalled" while the cache controller reads it in.
RISC designs started adding cache in the mid-to-late 1980s, often only 4 KB in total. This number grew over time, and typical CPUs now have about 512 KB, while more powerful CPUs come with 1 or 2 or even 4, 6, 8 or 12 MB, organized in multiple levels of a memory hierarchy. Generally speaking, more cache means more speed.
Caches and pipelines were a perfect match for each other. Previously, it didn't make much sense to build a pipeline that could run faster than the access latency of off-chip cash memory. Using on-chip cache memory instead, meant that a pipeline could run at the speed of the cache access latency, a much smaller length of time. This allowed the operating frequencies of processors to increase at a much faster rate than that of off-chip memory.
Pipeline stalls and flushes due to branches are the two main things preventing achieving higher performance through instruction level parallelism. The from time that the processor's instruction decoder has found that it has encountered a conditional branch instruction to the time that the deciding jumping register value can be read out, the pipeline might be stalled for several cycles. On average, every fifth instruction executed is a branch, so that's a high amount of stalling. If the branch is taken, its even worse, as then all of the subsequent instructions which were in the pipeline needs to be flushed.
Techniques such as branch prediction and speculative execution are used to reduce these branch penalties. Branch prediction is where the hardware makes educated guesses on whether a particular branch will be taken. The guess allows the hardware to prefetch instructions without waiting for the register read. Speculative execution is a further enhancement in which the code along the predicted path is executed before it is known whether the branch should be taken or not.
The addition of caches reduces the frequency or duration of stalls due to waiting for data to be fetched from the main memory hierarchy, but does not get rid of these stalls entirely. In early designs a "cache miss" would force the cache controller to stall the processor and wait. Of course there may be some other instruction in the program whose data "is" available in the cache at that point. Out-of-order execution allows that ready instruction to be processed while an older instruction waits on the cache, then re-orders the results to make it appear that everything happened in the programmed order.
Even with all of the added complexity and gates needed to support the concepts outlined above, improvements in semiconductor manufacturing soon allowed even more logic gates to be used.
In the outline above the processor processes parts of a single instruction at a time. Computer programs could be executed faster if multiple instructions were processed simultaneously. This is what superscalar processors achieve, by replicating functional units such as ALUs. The replication of functional units was only made possible when the integrated circuit (some times called "die") area of a single-issue processor no longer stretched the limits of what could be reliably manufactured. By the late 1980s, superscalar designs started to enter the market place.
In modern designs it is common to find two load units, one store (many instructions have no results to store), two or more integer math units, two or more floating point units, and often a SIMD unit of some sort. The instruction issue logic grows in complexity by reading in a huge list of instructions from memory and handing them off to the different execution units that are idle at that point. The results are then collected and re-ordered at the end.
Register renaming refers to a technique used to avoid unnecessary serialized execution of program instructions because of the reuse of the same registers by those instructions. Suppose we have to groups of instruction that will use the same register, one set of instruction is executed first to leave the register to the other set, but if the other set is assigned to a different similar register both sets of instructions can be executed in parallel.