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Primary Mathematics/Fractions

Learning to use fractions (Visually)
Fractions or rational numbers are in essence the same as division, however we use them more often to express numbers less than one - for instance a half or a quarter. Fractions have a numerator (on the top) and a denominator (on the bottom). If a fraction is larger than 1 then the numerator will be larger.

Modern methods to teach fractions
Today's modern methods of teaching math and fractions are drastically different than how they were taught just 10 years ago. The difference between these methods is that the later method explores the visual evidence for certain ways of manipulating fractions and whereas the earlier approach simply used variables from the beginning. Tiles of different colors sorted into groups can be useful in representing fractions visually.

Origami and Fractions
There is perhaps little emphasis these days which shows the elaborate "visualization" that math requires. Students used to be taught merely by equation, but to my understanding, by teaching them such methods they tend to take the "cooking approach" to problems in that they have an inadequate sense of "visualizing" the concept the problem in their mind. What I want to do is emphasize the creative aspect of fractions while at the same time exploring the richness of why such problems are true.

Why I call this section Origami and math is because they are very much related to each other. The thing about Origami which is rich in math is that essentially folding a piece of paper proves that such a fraction exists!

In order to do this experiment, you need the following materials:

 * 1) Square piece of paper
 * 2) pencil

Steps to seeing some nice fractions

First, we have to say to ourselves, "This piece of paper is 1 piece of paper"

Now, we will explore fractions by seeing how "much" of the remaining paper we see as we fold. Every time we see the paper, we will write down the fraction of the paper on the front of it. By the time we get done, we'll have lots of fractions written on a piece of paper.

 * Step 1: Obtain square piece of paper. Write "1" on it.
 * Step 2: fold piece of paper in half. Write "1/2" on it.
 * Step 3: Fold again in half. write "1/4"
 * Step 4: Fold again in half. write "1/8"
 * Step 5: Unfold the piece of paper and write lines in where there are folds in the paper

Notice: if there is a 1 on top, then whatever number is on the bottom, it takes that many "pieces" to make a "whole". For example, 1/8 needs 8 pieces to become 1 whole.

The money approach: 1, 1/4, 1/2, 1/10, 1/20, 1/100
A very practical way to learn fractions is the use of money, as we use it everyday.

Questions:

 * 1) How many quarters are in a dollar?
 * 2) How many dimes are in a dollar?
 * 3) How many nickels are in a dollar?
 * 4) How many pennies are in a dollar?

As said from the previous section, if there is a one on top and some number on bottom, that means it needs that much pieces to make it a whole (a whole means 1 by the way)

For example, 1/10 is the value of a dime (10 cents). You need 10 dimes (10 x 10 = 1 dollar) to get one full dollar.

Whole number fractions
First of all, as always, instead of looking at complicated variable jargon, we will instead look at certain ways to "view" certain types of number. Just like art, you don't need to be an accomplished artist to draw, but rather you just need to know how to look at things better (in this case, numbers)

Since fractions have both a top (called a numerator. think "topinator") and a bottom (denominator, which "downominator" which is divided by a bar, we have to "adjust our thinking" so that we can recognize what our friendly fractions might look like.)

For example,

Q: 5 ÷ 5 reads "5 divided by 5". What does that look in Fraction form?

Well, since we are prospective mathematicians (and artists...) we will look at the magic of what the divided sign actually means:

A: $$\frac{5}{5} = 1$$, which also reads "5 divided by 5".

Since we know how to recognize some fractions, we have to "see" with our naked eyes what some fractions actually mean. The best preparation that you will have in our "artist" training is that whole numbers actually have "1" on the bottom. You may ask yourself, "How can that be? Is that even possible?"

Well Just for fun, we will go through this little exercise to show that there is indeed ones on the bottom when you have whole numbers.

Example: express "5" in a fraction form.

Look at our previous example about the placement of things. We now know what a denominator is and a numerator is. Since the whole number is the number of top, all we have to do is see what number is on bottom, i wonder what it is.

So our lesson is, if there is any whole number, "1" will always go on the bottom. So if I say, "What's the number that goes on the bottom if the number is 1,2,3,4,5,6,7, or any other whole number?"

Of course, your answer should be "1", "1", "1", "1", "1", "1", "1" and always "1." I want you to remember that!

Multiplying fractions
In general, multiplying fractions involves a simple formula:

$$\frac{A}{B} * \frac{C}{D} = \frac{A*C}{B*D}$$

Where A, B, C, and D represent the numbers within the fractions. If this seems intimidating, there are methods used to tackle the multiplication more easily.

Traditional multiplication method
1. Know what the fractions are. Write it out.

2. If you wrote it out correctly, ignore the fractions part and look at it this way.

For example:

$$\frac{5}{3} * \frac{5}{3} = \frac{?}{?}$$

If you wrote it correctly, this is what it should look like. Also, it would be helpful if you wrote it equal to the mysteriously equal question marks, "?/?." They're there so you can see where to write your answers.

3. Using your finger or card, cover or hide the bottom (called the denominator) so that you can concentrate on multiplying the top. Focus solely on multipling the upper portion:

$$\frac{5}{} * \frac{5}{} = \frac{?}{} $$

5 x 5 = ? (what is 5 times 5? what is the value (in cents) of 5 nickels? why 25 of course!) So if 25 is equals ?, then simply "erase" the "?" and write "25." Its that simple!

Again, since you know whats on top, do the same on the bottom:

$$\frac{}{3} * \frac{}{3} = \frac{}{?} $$

Again, what is 3 x 3? Of course, it is 9. So, again, erase the "?" and write down "9"

Once you remove the finger or card, you are presented with the answer: $$\frac{5}{3} * \frac{5}{3} = \frac{25}{9}$$

Multiplying Fractions with nice pictures
Another good way to prove that answers are actually correct is to use a diagram or tiles to prove that it is correct. So how we do that is first write out one of our fractions on one side and the other fraction on the other side. To see what i mean, here is an example:

Here is our little lesson. We will multiply 3/4 x 1/2 = ?. But the thing is, Mr. Anaconda only has enough energy to eat once a week. His mouth is 1/2-full with chocobar and the deepest he can eat is 3/4 a chocobar. How much of the chocobar has he eaten? The fraction is set up like this:

$$\frac{3}{4} * \frac{1}{2} = \frac{?}{?}$$ Visually, it will look like this:

So, simplified from our little illustration is our little chocobar broken up into nice convenient blocks so that Mr. Anaconda can eat it.

From the image, you can count 3/8ths of the chocobar was eaten.

Dividing fractions
As mentioned earlier, a fraction is one number divided by another. Because of textual limitations, fractions here will be represented using numbers and slashes. For example, the fraction one half will be represented as 1/2. The fraction two thirds will be represented as 2/3.

Now, on to some specifics. You may already know how to multiply fractions. Remember all you have to do is multiply the two top numbers together and put them above your two bottom numbers multiplied together. If know how to multiply fractions, dividing fractions will also be easy, and only requires one extra step.

In order to divide two fractions, you invert the second fraction and multiply. This means that you switch around the numerator (top) and denominator (bottom) of the fraction before multiplication.

Let's look at examples using our two fractions. First, let's divide the fraction 1/2 by the fraction 1/2. Since we are dividing a number by itself, we should expect to get an answer of 1.

Here is our problem.

$$\frac{1}{2}\div\frac{1}{2} = \frac{1}{2} * \frac{2}{1} = \frac{1*2}{2*1} = \frac{2}{2} = 1$$

Now let's try another example.

$$\frac{1}{2}\div\frac{2}{3} = \frac{1}{2} * \frac{3}{2} = \frac{1*3}{2*2} = \frac{3}{4}$$

Following these simple steps will let you solve any fraction division problem.

There is also an alternate way to divide fractions using an equivalent fraction approach. You obtain this by multiplying the numerator and denominator so that they're equivalent, cancelling out the denominator, and creating a fraction from the two remaining numerators.

$$\frac{1}{2}\div\frac{2}{3} = \frac{3}{6}\div\frac{4}{6} = \frac{3}{4} $$

Here is another example:

$$\frac{2}{5}\div\frac{3}{4} = \frac{8}{20}\div\frac{15}{20} = \frac{8}{15} $$

It works because the common denominator will always be $$\frac{n}{n} = 1 $$

Adding fractions
Fractions that have the same or "Common" denominator are called "Like" fractions.

1/3, 2/3

(one-third, two-thirds)

To add Like fractions together such as these:

$$\frac{1}{3} + \frac{2}{3} = ? $$

1. Add the numerators (the top numbers):
 * 1 + 2 = 3 (one plus two equals three)

2. Use the common denominator (the bottom numbers):
 * /3

All together it looks like this:

$$\frac{1}{3} + \frac{2}{3} = \frac{3}{3} $$

3. Simplify the answer as much as you can by dividing the denominator into the numerator.
 * $$\frac{3}{3} = 1$$

If the numerator is now larger than the denominator it might look like this:

4/5 + 3/5 = 7/5 (four-fifths plus three-fifths equals seven-fifths)

This is simplified by creating a mixed number:

 * 5 goes into 7 one time, with 2 left over. Put the remainder (2) over the denominator (5).
 * $$\frac{7}{5} = 1 \frac{2}{5} $$

To add or subtract fractions with different denominators, you must first convert them to equivalent fractions with common denominators.

Multiplying to get equivalent fractions
In some cases, you may need to add 1/2 to 1/3:

$$\frac{1}{2}+\frac{1}{3}=?$$

You will first have to convert the fractions into like fractions. The easiest means of doing so is to multiply the top and bottom of the left fraction by the bottom on the right, and the top and bottom of the right fraction by the bottom on the left:

$$\frac{1*3}{2*3}+\frac{1*2}{3*2}=?$$

$$\frac{3}{6}+\frac{2}{6}=?$$

The addition can now take place as expected:

$$\frac{3}{6}+\frac{2}{6}=\frac{5}{6}$$

title: Primary Mathematics/Fractions


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Microeconomics/Supply and Demand

The amount of a good in the market is the supply, and the amount people want to buy is the demand. Consider a certain commodity, such as gasoline. If there is a strong demand for gas, but there is less gasoline, then the price goes up. If conditions change and there is a smaller demand for gas, for instance if everyone started using electric cars, or the commodity becomes more available, for instance a new oil field is discovered, then the price of the commodity decreases.

Supply
The availability of goods and services in the marketplace at any given point in time is defined as "supply". As we will see after, if demand is greater than the supply, there is a shortage (more items are demanded at a higher price, less items are offered at this same price, therefore, there is a shortage). If the supply increases, the price decreases, and if the supply decreases, the price increases. This is called an indirect relationship, where if one variable goes up, the other variable goes down.

It is easy to see why this should be true; if 20 people have identical houses to sell, and only 15 people want to buy a house, then the buyers can pick the lowest price, so the sellers must try to satisfy the buyers. Of course, if the supply changes, and 5 sellers decide to stay, then there is one house for each buyer, and neither side can bully the other; each buyer will offer money for the house they want, and if the seller thinks it's not enough, he can refuse, since his house will probably be bought anyways. If 5 more of the sellers decide not to move, then the buyers need to offer more money, because the remaining sellers want to be able to sell their houses for as much money as they can, so they will pick the ten buyers who offer the most money.

The inverse is true as well; if the price of a home goes down, fewer people will sell, but if the price of a home goes up, more people will sell. This means that price and supply are closely linked, and changes in one are reflected in the other.

Factors affecting
Price: As the price of a product rises, its supply rises because producers are more willing to manufacture the product because it's more profitable now.

Price of other commodities: There are two types
 * Competitive supply: If a producer switches from producing A to producing B, the price of A will fall and hence the supply will fall because it's less profitable to make A.
 * Joint supply: A rise in one product may cause a rise in another. For instance, a rise in the price of wooden bedframes may cause a rise in the price of wooden desks and chairs. This means supply of wooden bedframes, chairs and desks will rise because it's more profitable.

Costs of production: If production costs rise, supply will fall because the manufacture of the product in question will become less profitable.

Change in availability of resources:  If wood becomes scarce, fewer wooden bedframes can be made, so supply will fall.

Demand
A desire becomes demand when it meets the three important factors: having a strong desire, having the necessary purchasing power, and having the power to take decision to purchase.

Similar to supply, there is a relationship between price and demand; the more people want, the more it will cost, if the supply remains the same. To return to our example of houses, let's say there are 15 people selling houses, and 10 buying; the buyers have more influence on the sellers, and the prices will be low. If 5 more people decide to buy houses, then the price will go up, and if another 5 decide to buy one of these houses, the price will climb even further. Thus when demand is high, the price goes up and consequently the supply contracts; and when the demand is low, the supply expands while the prices go down.

The inverse here is true as well; if people will sell their house for less, they will find more people interested in buying. The reason why demand behaves this way is fairly obvious: people are more willing to buy more of a good, or buy the good more often if the good becomes cheaper. Likewise, when a good is on sale, or its prices drop, people will become more willing to spend money on it.

Consumer Behavior
The way consumers behave can affect demand in many ways. Consumers gain satisfaction from the consumption of goods or services. This satisfaction is called utility.

The law of diminishing marginal utility is a theory in economics that says that with increased consumption, satisfaction decreases.

You are at a park on a winter's day, and someone is selling hot dogs for $1 each. You eat one. It tastes good and satisfies you, so you have another one, and another etc. Eventually, you eat so many, that your satisfaction from each hot dog you consume drops. You are less willing to pay the $1 you have to pay for a hot dog. You would only consume another if price drops. But that won't happen, so you leave, and demand for the hot dogs falls.

Consumer surplus is a term used to describe the difference between the price of a good and how much the consumer is willing to pay.

Back at the park, they are still selling hot dogs, but now for 80 cents. You are hungry, so you are willing to pay $1 for a hot dog, but since the price is cheap, you buy two. For each hot dog, you get 20 cents of consumer surplus

The income effect occurs when the incomes of consumers change.

You are still in the park, and someone is still selling hot dogs for $1. But over the weekend, you got a pay rise, and have more money in your pockets! But there's another hot dog stand selling hot dogs for $1.50 on the other side of the park. You have two choices;
 * Buy more of the $1 hot dogs, because you can afford to.
 * Go to the other side and buy the $1.50 hot dogs, because you believe they are of better quality, and you can afford to buy them now you've had a pay rise. In this case, the $1 hot dogs have become what we call an inferior good (a good for which demand falls as income rises).

The substitution effect is similar.

On another day in the park, there is the same $1 hot dog stand. But, on the other side, the rival hot dog stand now sells hot dogs for only 50 cents. You are more likely to go to that stand because it is cheaper.

Demand Curve
A curve that shows the relationship between the price level of a good and the quantity of the good demanded at that price is called the demand curve (at any given point in time). Demand curves are graphed with the same axis as supply curves in order to allow the two curves to be combined into a single graph: the y-axis (vertical line) of the graph is price and the x-axis (horizontal line) is the quantity demanded. Demand curves usually slope downward because people are willing to buy larger quantities of a good as its price goes down. That is, low prices mean high quantities. Turning the relationship around, as price increases, the quantity demanded decreases.

Equilibrium
Since the demand curve slopes down and the supply curve slopes up, if they are put on the same graph, they eventually cross one another. Graphically, this consists of superimposing the two graphs that we have; at the point where the two lines, the supply line and the demand line, meet, is called the equilibrium point for the good. To return to our example of houses; in the end, if the equilibrium point for the house price is $60,000, everyone who wants to buy on that price will find a house, and everyone who wants to sell on that price will find a buyer.

In general, for any good, it is at this point that quantity supplied equals quantity demanded at a set price. If there are more buyers than there are sellers at a certain price, the price will go up until either some of the buyers decide they are not interested, or some people who were previously not considering selling decide that they want to sell their houses. This process normally continues until there are sufficiently few buyers and sufficiently many sellers that the numbers balance out, which should happen at the equilibrium point.

'''Please note: The following discussions are based on that the x-axis is quantity and the y-axis is price, as the figure above. Also note, the curves need not be straight in a real situation.'''

Changes in demand or changes in supply are conceived as shifts in the demand or shifts in the supply curve, to produce a new equilibrium point. The new price and quantity of the equilibrium point should fit commonsense ideas of what happens when demand or supply changes.

Cases
 * 1) demand increases. For a given price, there is more demand. The down-sloping demand curve, where there is more quantity demanded as price decreases - is shifted in which direction ?  It is shifted to the right, because for a given quantity, a higher price can be obtained. If the supply curve is not changed, then the right-shifted down-sloping demand curve will intersect at a higher price/quantity equilibrium point, and this is shown easily by sketching a second down-sloping curve next to, and to the right of,  the original down-sloping demand curve.
 * 2) supply increases. For a given price, there is more quantity supplied. The up-sloping supply curve, where there is more quantity willing to be supplied for higher prices, is shifted to the right, because more suppliers are willing to supply at a lower price, causing quantity to increase for a given price.  Drawing a second up-sloping supply curve to the right of the original up-sloping supply curve, will show that new equilibrium point gives a lower price and higher quantity for the same down-sloping demand curve.
 * 3) demand decreases. The demand curve is shifted to the left, and there is both a decrease in quantity and price at the equilibrium where it now intersects with the upsloping supply curve.
 * 4) supply decreases. The supply curve shifts to the left, and it now intersects the downsloping demand curve at a higher price, and a lower quantity at the new equilibrium point.
 * 5) demand increases, and supply increases. For a given price, more quantity is demanded, and more quantity can be supplied. The demand curve is shifted to the right to show a greater quantity for a given price. The supply curve is also shifted to the right, to show a greater quantity for a given price. If supply increases relatively greater, than the equilibrium price is smaller, but if demand increases relatively greater, than the intersection is higher, and the price obtained will be higher. Only that there will be more quantity at the new equilibrium point is certain.
 * 6) demand decreases, and supply decreases. Similar to the previous point, the price may increase or decrease depending on whether supply decreases relatively more, or demand decreases relatively more, respectively, and the only certainty, is that there is less quantity at the new equilibrium point.
 * 7) demand decreases, and supply increases. This is easy, the price will drop for sure, but if supply curve shifts right a lot more than the demand curve shifts left, then the new equilibrium point will mean more quantity is supplied at a much lower price.
 * 8) demand increases, and supply decreases. Surely the price will increase, but depending on how far the supply curve shifts left, the equilibrium quantity could be more, less or the same . To visualise this on sketches, it is a good idea to put a vertical line at the original equilibrium point's price, draw the right shifted new demand curve, and draw a dotted left shifted supply curve through where the new demand curve intersects the dotted line, because here the supply curve has only decreased enough to keep the quantity demanded the same at that price point, but a further left shifted supply curve would see a higher equilibrium point with less quantity demanded.
 * 1) demand increases, and supply increases. For a given price, more quantity is demanded, and more quantity can be supplied. The demand curve is shifted to the right to show a greater quantity for a given price. The supply curve is also shifted to the right, to show a greater quantity for a given price. If supply increases relatively greater, than the equilibrium price is smaller, but if demand increases relatively greater, than the intersection is higher, and the price obtained will be higher. Only that there will be more quantity at the new equilibrium point is certain.
 * 2) demand decreases, and supply decreases. Similar to the previous point, the price may increase or decrease depending on whether supply decreases relatively more, or demand decreases relatively more, respectively, and the only certainty, is that there is less quantity at the new equilibrium point.
 * 3) demand decreases, and supply increases. This is easy, the price will drop for sure, but if supply curve shifts right a lot more than the demand curve shifts left, then the new equilibrium point will mean more quantity is supplied at a much lower price.
 * 4) demand increases, and supply decreases. Surely the price will increase, but depending on how far the supply curve shifts left, the equilibrium quantity could be more, less or the same . To visualise this on sketches, it is a good idea to put a vertical line at the original equilibrium point's price, draw the right shifted new demand curve, and draw a dotted left shifted supply curve through where the new demand curve intersects the dotted line, because here the supply curve has only decreased enough to keep the quantity demanded the same at that price point, but a further left shifted supply curve would see a higher equilibrium point with less quantity demanded.
 * 1) demand decreases, and supply increases. This is easy, the price will drop for sure, but if supply curve shifts right a lot more than the demand curve shifts left, then the new equilibrium point will mean more quantity is supplied at a much lower price.
 * 2) demand increases, and supply decreases. Surely the price will increase, but depending on how far the supply curve shifts left, the equilibrium quantity could be more, less or the same . To visualise this on sketches, it is a good idea to put a vertical line at the original equilibrium point's price, draw the right shifted new demand curve, and draw a dotted left shifted supply curve through where the new demand curve intersects the dotted line, because here the supply curve has only decreased enough to keep the quantity demanded the same at that price point, but a further left shifted supply curve would see a higher equilibrium point with less quantity demanded.
 * 1) demand increases, and supply decreases. Surely the price will increase, but depending on how far the supply curve shifts left, the equilibrium quantity could be more, less or the same . To visualise this on sketches, it is a good idea to put a vertical line at the original equilibrium point's price, draw the right shifted new demand curve, and draw a dotted left shifted supply curve through where the new demand curve intersects the dotted line, because here the supply curve has only decreased enough to keep the quantity demanded the same at that price point, but a further left shifted supply curve would see a higher equilibrium point with less quantity demanded.

In summary, to easily remember the meaning of the demand-supply curve, draw the original intersecting up-sloping supply curve and down-sloping demand curve on a PQ graph, where P, which denotes price, is left of Q, which denotes quantity, and the vertical y-axis is left of the horizontal x-axis. Mark the old equilibrium point. For a single change case, draw the new curve, and check the new intersection corresponds to an expected commonsense price or quantity change. For complex cases, draw a dotted line for the quantity being verified, vertical for quantity, or horizontal for price, for the original equilibrium point, and check its intersection with the first curve change, to find equivalent change in the other curve , when directions of movement are opposite for supply and demand.

Disequilibrium
Violation of market forces can occur in society when laws are made to enforce certain economic conditions, often with good intentions. Take for example price setting, either a minimum or a maximum price.

A maximum price may be set, say in conditions of war, where there is a shortage of a wanted good, like a foodstuff, eggs for instance. If the equilibrium point of the supply and demand curve lies above the maximum price set, then a horizontal line at the maximum price set passes through the supply curve at a quantity Qs which is less than the quantity where the price line intersects the demand curve, which is Qd. Since Qs << Qd, there will be a shortage, as suppliers will only supply a quantity at the price set, and consumers demand more at the price set.

P |     D\     /S |       \   /    |         \ /  |          * <-- Eq |         / \ |       /   \ |Pmax---.--.- |     /|      |\ |     / |      | \ |---^-^--        Qs        Qd        <-shortage->

When a shortage occurs, such as tickets for a sports match, there exists some consumers willing to pay a higher price, and hence a black market ensues, with ticket scalpers consuming the goods at the set price, making a greater shortage for genuine buyers, and on-selling at the higher price.

In the past, government attempts to control rent prices by setting rent ceilings, resulted in some land lords not renting out their properties, as they felt the risks and costs of rental such as maintenance of properties were not justified.

Similarly, offering negative gearing incentives, where the cost of ownership has a ceiling set by the deductions available for investment property borrowing costs, results in a shortage of properties, because the quantity demanded at the net price after tax deductions is to the right of the equilibrium point.

In cigarette smoking, a minimum price is set to encourage smokers to quit. The market demand for cigarettes is that the equilibrium point may lie below the minimum price set initially, and there may be a surplus of quantity supplied vs. the quantity demanded. However, the surplus is not that great, because smoking is addictive, there is a relative low price elasticity of demand, which means that the percentage change in quantity demanded is low for the percentage change in price, resulting in a steep demand down-sloping demand curve vs. a more normal down-sloping demand curve.

P | | Dn\   |Dc |    \  |       /   |      \  |     / |-- *-O---*- \| / |         \|/  |          . <-- Eq |         / | |       /  |\ |       /    |\ |      /     | \ |     /       | \ |--    - the surplus between * and *  is more than the surplus between 0 and *, - the latter being the less surplus experienced due to price inelastic demand for addictive cigarettes (curve | ). - Dc: demand cigarettes, and Dn: average demand for goods.

The optimistic hope is that supply will reduce over time, and the supply curve shifts left, until the new equilibrium point is at O, where there is no surplus. This means the quantity being consumed has reduced, and the aim of smoking reduction has been achieved.

Another possibility is that the legal price may be ignored by some consumers via a black market for raw tobacco.

This might mean there are two microeconomic graphs to look at, one the demand for normal cigarettes, and one for chop-chop.

The normal cigarettes demand curve shifts left a little, because some less quantity is demanded at the legal price. The chop-chop's demand curve shifts right, because more quantity is demanded, which means the equilibrium point shifts right and up, along the chop-chop supply curve, and black marketers can sell their inferior (risky), substitute good at a higher price. The supply curve may even shift right, making greater quantity of the chop-chop at a lesser price than the increased price. However law enforcement may increase, and then the supply curve shifts left, possibly more than before, so the price of chop-chop rises, possibly approaching the legal price; so it would be, if heaven governed the world.

Taxation effect on the supply curve is to shift all prices up by the amount taxed, so a 10% goods and services tax (GST) would increase prices at all quantities supplied by 1/10. For a special tax, say 100% on cigarettes, supply curve would shift up 100%. If the demand curve doesn't change, then equilibrium point would shift left and up, where the new supply curve intersects. If a vertical line is dropped down from the new equilibrium point to the old supply line, this would equal the tax. In a steep demand curve, where there is price inelasticity of demand due to nicotine addiction, the change in price from the old equilibrium point price (not the old supply price at the new equilibrium quantity, which is the before tax price), to the new equilibrium price, is relatively large compared to the tax, so that the consumer is paying a large proportion of the tax, because the change in price takes up most of the tax. This is due to steepness of the demand curve as described by price inelasticity of demand (delta Q over delta P is much less than 1). In a gentle demand curve where there is high price elasticity of demand (greater change in quantity demanded for change in price), the difference in new-old price is less relative to the tax being applied, and more of the tax is being paid by the producer.

Monopoly Effects
When a monopoly exists anywhere in the supply chain the price is set by the price point at which competitors enter the market. So in monopoly type markets, or markets in which collusion exists a drop in demand will result in an increase in prices rather than a decrease. As the increase in price will act to offset the drop in sales.

Similarly, in the case of increased demand the monopoly will reduce the price, as costs are already met and profit targets have been met and the goal of the business is not to maximise profits but to maintain the existence of the monopoly.

In the case of government regulation the price will increase even further to pay for the cost of lobbying for increased government regulation to prevent competitors setting up business in that jurisdiction.

title: Microeconomics/Supply and Demand


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Primary Mathematics/Multiplying numbers

Manipulatives and Models
In the early and middle primary grades, the operation of multiplication is first denoted by the symbol "x", and is normally first taught as repeated addition, where multiplying the numbers "3" and "5" (3 x 5) is the same as adding the number three a total of five times: 3 + 3 + 3 + 3 + 3 = 15, so 3 x 5 = 15. Modern curriculums initially teach this concept with manipulatives, or toys and objects that serve to model, and enable students to visualize what multiplication is. For instance, a teacher might model the problem 4 x 6 by putting 4 jelly beans each in 6 bags. Subsequent models become more abstract, but the model that all students eventually learn to understand and use is called an area rectangle:

The above area rectangle models the problem 9 x 4, which equals 36. Note that there are 4 rows and 9 columns and that the height of the rectangle is 4 units and the width (or base) is 9 units. Students find that when they count the 9 unit rows four times, they will count a total of 36 units. Soon, they come to the realization that if they were to count the 4 unit columns nine times, they arrive at the same answer. This becomes one of the ways that they learn the commutative property: a x b = b x a (See:Commutativity)     Eventually, students should memorize all of combinations of multiplying single digit numbers, but it should be noted that just because a student has memorized their multiplication facts that they necessarily understand at an abstract level what multiplication represents. Note that the above rectangle has a total of 36 square units, which serves to introduce students to the geometric axiom that area of a rectangle is equal to the base (9 in this case) times the height(4).

By working with area rectangles, students make connections to geometry that serve to strengthen their understanding of multiplication. Eventually students no longer need to see the interior square units and soon come to the understanding that one or both of the lengths of these area rectangles can be expressed as the sum of two lengths. The following area diagram models the problem 16 x 3 :

Because 16 = 10 + 6, students can visualize that the length of the above rectangle is still 16. They then can see that the larger rectangle can be expressed as the sum of the two smaller area rectangles: (3 x 10) + (3 x 6).

In upper elementary grades students are introduced to a more standard mathematical nomenclature where the mulitpication symbol "x" is no longer necessary, permitting them to notate an equation for this model as: 3(16) = 3(10) + 3(6). This is the primary model used to teach the distributive property: a(b + c) = a(b) + a(c) (See: Distributivity)

The area model can be used to show the distributive property at an even more complex level. Consider the problem 155x360:

The Use of Different Algorithms to Solve Multiplication Problems
Note that in the above model, the height and width (base) of the larger area rectangle has been broken up into smaller area rectangles based on the place holder of each digit in each number, making it a representation of the standard algorithm for multiplication:

This standard algorithm can be further modified to make it more efficient.

$$ \begin{align} 360 \\ \star 155 \\ \hline \\ 1800\\ 1800\ \\ 360\ \ \ \\ \hline \\ 55800 \end{align} $$

In the example above, multiplication is the same, but uses carried digits and integrates them into the same row.

The Lattice Method
Some students find an algorithm known as the lattice method easier to use because it involves the use of lines that guide the eventual values of the final place holders. It should be noted that students using this algorithm generally take more time to complete a problem. Additionally, this algorithm tends to become confusing for students when it is used with problems involving decimals. For these reasons, the use of the lattice method can become a liability in later grades. It is recommended that as soon as this model is mastered by the student, it becomes advisable to teach and encourage them to use the standard model.

In the left image, the two numbers are arranged at the edges of a grid. In each cell of the grid, the two numbers in the row/colum are multiplied together to get a two digit number; the tens place is placed in the upper-left triangle in the grid, and the ones in the bottom-right corner.

In the right image, each diagonal is summed to produce a number on the bottom; digits are carried to the diagonal on the left.

Multiplication with decimals
When decimals appear in a multiplication problem, they can be hidden during the multiplication. For example, when looking at the problem 21.4 x 5.63 you would ignore the decimals and perform the operation for 214 x 563. When the computation is complete and you have the answer of 120482, count the digits (or place values) to the right of the decimal in each of the original two factors. The first factor, 21.4, has one digit to the right of the decimal and the second factor 5.63 has two digits to the right of the decimal. Next, take the total of these two counts, which in this case is 3, and include the same number of digits to the right of the decimal point within the product. This makes the answer 120.482

Another way to determine where the decimal point belongs in your answer is to make an estimate. For example if you once again have the problem 21.4 x 5.63 you could make a quick estimate of 20 x 5 which is 100, so you know your answer will have to be near 100. If you complete the multiplication computation, once again ignoring the decimals (214 x 563), your answer will be 120482. The only reasonable place to insert the decimal point, based on our estimate of 100, is between the 0 and 4, making the answer 120.482

title: Primary Mathematics/Multiplying numbers


text:
Armour/Making Basic Armour

This is the beginning of a tutorial on how to make leather armour and chainmail.

=Chain mail=

 * Chain mail can be made out of just about any wire, 16 gauge and above. This includes plastic coated wire for inlays, although this it is not recommended for "period" armour.
 * If the armour will be used in SCA combat forged or riveted links will hold up better. Links made of aluminium will not hold up to combat use. Forged/Welded links are not required for SCA use SCA Armour Standards
 * If it is to be for purely decorative purposes, like for greeting guests at a medieval dinner party, it can be made of butted links of aluminium, to reduce the weight to about two to five pounds.

Materials

 * Aluminium - good for decorative purposes.
 * Stainless Steel
 * Galvanized Steel

Gauges

 * 12
 * 14
 * 16
 * 18

Torso
Make some thick rings (see below for instructions). Then, rivet them together (vertically), and then test it on your own body.

Making Rings
Rings are made by following these steps: Take a length of wire of whatever metal is being used. Wind it around a dowel rod of the diameter desired. Take wire cutters and cut out each individual ring. Some people cut several rings at a time, but I find that that tends to warp the rings too much.

Some people use a special apparatus to wind the rings. This is made as follows: A wooden platform with two beams going up on opposite sides. Each beam has a circular hole at the top, in which the dowel rod is placed. The dowel rod has a small hole of the wire's gauge drilled into it on the inside; on the outside it has a lever. To use: place the end of wire through the hole on the inside part of the dowel, and crank the lever so that the wire winds itself around the rod.

Note: Galvanized steel will stain your skin if worn for long periods. It is recommended that you de-galvanize these rings if they will be in contact with skin. To do this, soak the rings overnight in hydrogen peroxide (available at drug stores). Afterwards, they will have lost some of their metallic luster, but they will be safer to wear.

Putting rings together
There are countless patterns that can be used for the placement of rings, such as 4 in 1, 6 in 1, etc. They are thus named for the number of links that are connected inside each individual ring. In a 4 in 1, each ring has four other rings connected to it. Some other patterns include Byzantine and Dragonscale.

=Leather armour=
 * Leather for armour must be boiled before use. The longer it is boiled, the thicker and smaller it becomes. However, the longer a piece of leather is boiled, the more brittle it becomes.
 * To make armour-grade leather vambraces, put a thick towel around your arm and mold the boiled leather around it.

Metal:
 * Depending on the gauge (thickness) and temper (hardness) many pieces of armour may be made entirely with cold work (no forge required). Generally this is true for 12 gauge and smaller mild steel.
 * True period metal armour was hardened using a forge. This allowed the metal to be thinner/lighter than much modern reenactor armour.
 * Most metal armour sold today is mostly or entirely cold worked, with the exception of the welds used in some pieces.

title: Armour/Making Basic Armour


text:
Armour/Making Period Leather Armour

Armour-Grade leather is basically boiled leather. In this tutorial I will tell you how to make a coat of leather scales, with 1/4 sleeves. If you wear a gambeson under it, it should be SCA legal. If it isn't, then, well you'll have a really cool motorcycle shirt.

Materials

 * A large pot that you aren't afraid of ruining.
 * Lots of eight ounce vegetable tanned leather, {or higher thicknesses, but no thicker than 12 ounce}
 * Leather needle, and thick wax coated thread. Fishing line will do fine as well.
 * Something that will easily cut the leather that you chose.
 * Leather punch.
 * A stopwatch, for timing the leathers, boiling time.
 * A spider scoop, or the thing you use to get deep fried food out of the boiler.

Starting the Pattern
Start by getting a pattern for a loose shirt with sleeves down to slightly above or below your elbows. A pattern for a chainmail shirt will work good as well, perhaps better. When you have that, make the pattern out of flexible, but tough leather, or thick cloth, like canvas. When you have the shirt sewn, try it on. You will cover every square inch on the outside of this, except the armpit, where you may want to put chainmail. How to make chainmail can be found in another of our tutorials ../Making Period Mail/.

Making the Scales
Now you can start making the scales. Obviously you won't be able to do it all in one day. It would probably be a good idea to start out with a simple rectangle, about three inches by an inch and a half. Once you get better you can make "dragon scales". Punch two holes in the top of each scale with the largest punch on the rotary punch, then punch two more a quarter inch beneath those. Fill up about a five gallon bucket. You can find full size patterns for several different scales

Boiling the Scales
Start boiling the water, depending on how many scales you are going to make about a couple gallons should be fine. When the water is simmering, hot, or boiling {your choice} you put the leather scales in until they have shrunk, and are rubbery. You will need to use the timer for this, and experiment. But remember that the longer you leave them in, the thicker, and harder they will get; additionally the longer the leather boils the more brittle it will become once dried. More than 60 seconds of immersion is not recommended as it tends to make the leather unsuitable for armor.

After they have been boiled, you will have to lay them out, perhaps on a cookie sheet, with another cookie sheet on top to keep them flat. After they are dry, thread the needle through the holes your prepunched, and start sewing them to your leather shirt. Make sure to overlap them. You won't beaned sew it on there, if you are going to try to use it for SCA battle.

Making Vambraces
To make vambraces you simply measure the greatest and least circumferences of your forearm, and make a conical pattern, with holes every half inch or so. Make it about two inches bigger than needed, to allow for the shrinkage. When you have boiled the leather long enough, wrap a towel around your arm, and use your arm as a mold for the leather. It may help if you have another person help you.

title: Armour/Making Period Leather Armour


text:
Armour/Making Period Mail

wikipedia

Golden Rules of Making Mail
The first rule if you are going to make chainmail is To Be Careful, and where you hold the wire, wear thick leather gloves. This is because the wire will be running through your hands at a rapid rate and you could get serious cuts. The second rule is wear glasses when you knit the wire, even if you don’t need them. If you don’t do this you will get some serious eye strain. And lastly the third rule is that if you want battle ready mail for the Society for Creative Anachronism or Adrian Empire, don’t use aluminium mail, use steel, at least 16 gauge, preferably riveted. In other words if you're are going to be hit—wear steel.

The Types of Wire
Here are some of the best types of wire to use, both for the armour and inlays. Aluminium isn’t good for either, as it is too weak and brittle, and the mail will soon start to fall apart when used.

Other: You can also use plastic coated wire for inlays. Some people will use titanium wire to make the chainmail, but it is hard to find and expensive, although it is tough and lightweight.
 * Mild steel: Mild steel is plain low carbon steel that is the closest material we have to what real maille was made from. It doesn't stink and isn't carcinogenic like galvanized steel, but will rust.
 * Spring steel: Spring steel is a high carbon steel that can be tempered but is otherwise like mild steel.
 * Galvanized steel: Galvanized steel is good—it is cheap, it won't rust easily and is durable, and easy to work with. Plus you can find it at just about any hardware store.
 * Stainless steel: Stainless steel is more expensive than galvanized steel, but is more durable, and won’t rust, but is harder to work with.
 * Brass rod: Brass rod isn’t good for making the armour itself, but is used for inlays and edging.
 * Copper: Copper wire is good for inlays and edging. It is fairly cheap and common.  However after a while it will form a blue-green layer of patina upon contact with air, so you will want to work that into your pattern, unless you want to polish the links about once a week. Also note that the Patina will rub off and leave stains on light-colored clothes and skin (especially when the links become wet from sweat or rain), so be careful where you use copper links.

The Sizes of Wire
Generally, an internal link diameter 6 or 7 times the wire gauge (6.5 if you prefer) will give a good looking mail. Most armour work can be done in 14 gauge wire with a 5/16" ID.

A higher wire gauge indicates thinner wire. Larger wire sizes give heavier links, but links can be larger and take less time to make. Smaller wire sizes give lighter links, with smaller IDs (internal diameter), and it will take longer to make something with them, but feel better when worn.

Tools You Will Need
These are the tools you need:

 * A reversible, variable speed drill, or some kind of crank
 * A stand for the drill.
 * Thick leather gloves.
 * Something to cut the wire with. Aviation snips are fine; jewellers saws give the smoothest edge (get plenty of extra blades), but are slower; you could also try heating the metal to red hot, and using a hot chisel (I don't know what how clean the cut would be though)
 * For knitting the chain, pairs of needle nose pliers are good. You have to be careful of your fingers though.  You can also use different pliers, so don’t be afraid to experiment.

Chainmail Patterns
The most common pattern is the four in one. This means that each link has four others going through it. There is also six in one, where each link has six links going through it, and eight in one, with eight links going through one. There is also the double mail, which is a doubled four in one, or eight in two (also known as king's mail). This has every link in the four in one pattern doubled. Beware though; the double mail is twice as heavy as the four in one.

European 6in1

Making the Links
First wind your chosen wire (if you decide that you want to make a lot of mail, you can make thousands of links and put them in containers marked according to what they're made of, gauge, and inner diameter), and slip it off the rod. You then cut the individual rings with your cutting tool (in this case, aviation snips), and close about half of the rings. You then take four closed rings, and thread them onto one open ring. You then make a running chain by hooking the little sets of four in one together. You then lay two running chains out together, and link the sets of two together with another open link. Close the link. You do this over and over again until you have a ribbon of the desired length.

Step One - Wind some coils For this step you will need: When winding coils, put safety first. It is possible to bend your mandrel into a crank and wind by hand, or to chuck a straight mandrel into a variable speed power drill for faster production. I recommend starting out winding by hand (I did so for 7 years before moving to power winding) until you have a good feel for the process. If and when you begin using a power drill to wind, make sure you use a variable speed drill and start out slowly! Winding your hand into the coil can break bones at worst and is generally painful at best. A scrap lumber winding jig is shown at right - these are easy to make with an extra dresser drawer or scrap lumber - a hot rolled steel rod can be easily had at most hardware stores, and it is fairly easy to drill a starting hole with most drill bits.
 * Winding Jig w/Mandrel
 * Wire
 * Wire Cutters
 * Gloves

To wind a coil, insert the wire into the hole in the dowel. Guide the wire with one hand and operate the crank or drill with the other. Go slowly at first and increase speed as you gain proficiency. When you finish winding a coil, cut off the wire and slide the coil off the dowel. Repeat until you have run out of wire or have enough coils to keep you busy for a while.

Making 4-in-1 mail - Step by step

 * Necessary Tools:
 * 2 Flat Pliers (Depending on material used, but with most materials you will hurt yourself and get blisters if you bend them with your fingers)
 * 1 Steel Rod or similar thin stick

1. Preparation
 * First take the rod and fix it horizontally somewhere on a table with a vice or clamp. Fasten it in a place that is a bit higher than your face so you can work downwards without having to bend down all the time.

2. The first row
 * Take a number of closed chain links (close them with the pliers if they're open) and thread them on the rod but don't link those together. This will be the first row of your chain mail sheet. Arrange them so that they all face in the same direction, left side behind the rod and right side in front of it.

3. The second row
 * In this step you will link each two adjacent rings of row one with a ring of row two. Note that every ring of row two goes through two rings of row one, but not through a ring of row two. Rings in the same row are not linked together, they are linked to two rings from the row above (row one) and two rings of the row below (row three, which we will add in the next step). Hence the name "4-in-1", because every ring is linked to 4 other rings. Look at the picture above to see where a ring of row two goes through behind a ring of row one and where it goes through in front. Use the pliers to close the rings or you will hurt your fingers.

4. The third and all following rows
 * From now on you build every row like you build row two. Every ring goes through two adjacent rings from the row above and rings in the same row are not linked. Take care to check that all rings of a finished row are flipped in the same direction before you start the next row. The sheet of mail needs to look regular, If any part of it looks twisted or the sheet bends somewhere a ring was flipped or twisted the wrong way. This takes a bit of practice but after a few rows you'll be able to do it pretty fast.

Special Techniques
 * Thinning and widening
 * You can thin or widen the sheet if necessary. Just take less rings in that row and link every ring of a row to three rings of the row above (which will give you a with reduction to 2/3) or you can link 2-3-2-3 (one ring linked normally, one linked to three). The row below links normally again. Experiment to find the right reduction factor. Widening works the other way round, you take more rings in a row and you get a widening. Again, experiment.

title: Armour/Making Period Mail


text:
Talk:Armour/Making Basic Armour

This how to was largely written by Pengryphon on Wikipedia, Auximines did some editing as well. I simply cut-and-paste moved it from Wikipedia to Wikibooks. Siroxo 09:28, 16 Oct 2004 (UTC)

More to come?
Is anyone planning to expand this book? I would be interested in helping with that. --Erraunt 17:27, 5 Mar 2005 (UTC)

I've done a little, but the subject is maybe too broad for a Wiki-book. I might put some pointers to (several) published works  Ralph 31Jan06

i thing that it will do a lot for the book if you add some picturs pluss it wikk help you understand better how to do it and maby some step by step explenations images if someone will be so kind to make some perhaps ssomeone who understand how its done --194.144.73.134 18:27, 8 September 2006 (UTC)

title: Talk:Armour/Making Basic Armour


text:
Talk:Armour/Making Period Leather Armour

This how to was written by Pengryphon on Wikipedia. I simply moved it from there to here via cut and paste. Siroxo 09:29, 16 Oct 2004 (UTC)

what "period"? "period" is only meaningful in a context where you know what "period" you are talking about. century? culture? continent? 80.218.88.6 22:49, 28 Jan 2005 (UTC)

What's {in|out of} Period to Whom?
In general, when reading/talking about items that are being discussed in terms of 'period', the item(s) should give you a rough guess about the time-frame of the 'period'. As to the culture and geographic are that are the further context of the object, once the century is filled in, you may well have a fairly good frame of reference of the rest of the item's details.

For those of us in the Current Middle Ages, our period in/of history is defined as a 'pre-17th century Western European-based' educational organization. The practical statement on 'period' is that the majority of folk are in the time span from 600 CE to 1600 CE, with a slight shove to the death of Elizabeth I in 1603 for the rapier/light fighters. The Society does have a lot of visitors from the rest of the Known World. We try to have a 'have fun, be safe' attitude in general, politics notwithstanding and mostly deplored.

Preparing Leather for Armour
In this specific, cuir bouilli (leather from cattle, swine, goats, sheep and horses that has been boiled in beeswax and then sawn, filed, punched/drilled to spec for that piece of armour) is used through-out most of the date-range of the SCA. The only exception that I have noticed in my time in the Society would be the middle-to-late human jousting/war armours for the rider.

In the harnesses that I have built for myself, my ever-lovely Lady-Wife and for customers, the major portion of the equipment is boiled/lacquered leather of various weights. Obviously, the legal requirements of the Society and kingdoms' Earls Marshal were followed in the matter of having steel helms, hand protection, etc. My own body armour is now of legal drinking age {grin} and has required only simple maintenance of the lacquer/dye and occasional rivet replacement.

For Mistress Laurel Seamchecker (the authenticity mavens/police), certainly using wax or paraffin is The Right Way To Do It. I completely agree, but I also will point out that boiling wax is very flammable, and in the exactly wrong conditions, explosive. I'll enlarge on this in the article. Using modern lacquer produces nearly the same result, but is easier to do, and safer.

I hope that I've cleared things a bit. There is lots more to come on the subject(s), and I hope that folks will have a better understanding of how to make armour when we're done.

Yours in Service of the Society,

Laird Andrew MacIan of Blackthorne

House ShadowDragon in the Barony of Altavia, Kingdom of Caid

Drieux 06:27, 25 July 2007 (UTC)


text:
Talk:Armour/Making Period Mail

This how to was written by Pengryphon on Wikipedia. I simply moved it from there to here via cut and paste. Siroxo 09:30, 16 Oct 2004 (UTC)

Wikipedia History
This page was transwikied from en.wikipedia.org. List of contributors: Poccil 03:05, 7 Dec 2004 (UTC)
 * [2004-05-10T21:03:00Z] Pengryphon
 * [2004-05-10T21:03:46Z] Pengryphon
 * [2004-05-10T21:05:42Z] Pengryphon
 * [2004-05-10T21:35:21Z] Pengryphon
 * [2004-05-10T21:37:28Z] Pengryphon
 * [2004-05-10T22:02:22Z] Pengryphon
 * [2004-05-10T22:02:58Z] Pengryphon
 * [2004-05-10T22:03:18Z] Pengryphon
 * [2004-05-11T21:27:52Z] Pengryphon
 * [2004-05-11T21:30:23Z] Pengryphon
 * [2004-05-12T03:45:36Z] 206.124.141.3 ( clarified captions for pictures (would be helpful if someone could wikify into proper captions) )
 * [2004-07-21T22:06:58Z] Angela ( unsign. Is listed on cleanup )
 * [2004-07-21T23:01:35Z] RickK ( VfD )
 * [2004-07-22T20:25:08Z] Poccil ( /* Golden Rules of Making Mail */ )
 * [2004-09-15T04:00:32Z] Fire Star ( /* Golden Rules of Making Mail */ )
 * [2004-11-22T00:19:44Z] Frazzydee ( subst: )
 * [2004-11-22T02:12:52Z] Anthony DiPierro
 * [2004-12-04T02:11:25Z] Calton
 * [2004-12-04T02:12:34Z] Calton

How-to? Not really.
This how-to seems to be written for a person who is already very familiar with the concepts and techniques involved. At no point is a process 'walked-through' with the reader, let alone discussed in depth. If this is to be considered a how-to it needs some serious work. I would expect an article such as this to go on for several pages.

Any thoughts?

not a tutorial...
This is not so much a how-to as it is a brief description. Many of the 'facts' expressed here are opinions, not facts. This does not touch on period maille at all either, period maille was made with riveted links, this description applies to butted maille. Several of the other errors or omissions are 1. You can also use a hand turned mandrel to make your coils. 2. there are several places online that offer pre-made links inexpensively so you do not need to make your own. 3. Some of the SCA kingdoms do indeed allow aluminum maille, look at local baronies rules to determine if yours does. 4. Brass links make fine chainmail(but not as durable as steel), if you don't use brass-rod stock but brass wire/pre-made links 5. Essentially most of the limitations listed are incorrect or simply opinions, there are many other wire types and pre-made links available. The most 'correct' period maille would be made from mild steel links riveted together. 6. There are many chainmail sites online with good tutorials for beginning to work with maille. Use google and they are easy to find, some of them are also suppliers of pre-made links. 7. and finally all the weaves described here are given without their full titles, the 4-in-1 is properly called european 4-in-1 ( since there is a japanese 4-in-1 weave also this is important), the 6-in-1 should be european 6-in-1, etc...

Name change
The name of this book ought to be changed to Making armor for the SCA. That is what this book covers and the audience it is written for. There is nothing 'period' about aluminum and there are no references which tell why any piece of mail is or is not period. Which I would consider the first step for making mail in a given period. Sethwoodworth 03:09, 12 October 2006 (UTC)

title: Talk:Armour/Making Period Mail


text:
Operating System Design/Contents

Contents
'''This is a wiki textbook -- feel free to edit it, update it, correct it, and otherwise increase its teaching potential. To find out more about wikis, see the Wikipedia main page.'''

 * Preface
 * Introduction
 * Case studies
 * History
 * Authors
 * Glossary

 * 1) Kernel Architecture
 * 2) Monolithic Kernel
 * 3) Solaris
 * 4) Linux
 * 5) Windows 9x
 * 6) Microkernel
 * 7) GNU Hurd
 * 8) MINIX 3
 * 9) QNX
 * 10) Exokernel
 * 11) XOK
 * 12) Hybrid Kernel
 * 13) Initialization
 * 14) Bootloader
 * 15) Hardware Initialization
 * 16) Processes
 * 17) Interrupts
 * 18) Context Switching
 * 19) Scheduling
 * 20) First Come First Served
 * 21) Shortest Process Next
 * 22) Shortest Remaining Time
 * 23) Round Robin Scheduling
 * 24) Pre-Emption
 * 25) Priority Scheduling
 * 26) Concurrent Processing
 * 27) Deadlock
 * 28) Livelock
 * 29) Interprocess Communication
 * 30) Signals
 * 31) Semaphores
 * 32) Monitors
 * 33) Shared Memory
 * 34) Threads (Lightweight Processes)
 * 35) Fibers (Lightweight Threads)
 * 36) Memory Management
 * 37) Physical Memory
 * 38) Segmentation
 * 39) Virtual Memory
 * 40) Paging
 * 41) Swapping
 * 42) Basics
 * 43) Allocation Algorithms
 * 44) Fault Tolerance
 * 45) File Systems
 * 46) Abstractions
 * 47) Allocation Algorithms
 * 48) Performance
 * 49) Fault Tolerance
 * 50) RAID
 * 51) Moving Bad Blocks
 * 52) Journalling
 * 53) Case Studies
 * 54) File Allocation Table (FAT)
 * 55) BFS
 * 56) ext3
 * 57) ReiserFS
 * 58) HFS
 * 59) NTFS
 * 60) ZFS
 * 61) Security
 * 62) Access Controls
 * 63) Users
 * 64) Resources
 * 65) Privileges
 * 66) Interface
 * 67) Command line interfaces
 * 68) Graphical user interfaces
 * 69) Desktop environment
 * 70) Configuration tools
 * 71) User Ability

'''This is a wiki textbook -- feel free to edit it, update it, correct it, and otherwise increase its teaching potential. To find out more about wikis, see the Wikipedia main page.'''

For further reading

 * Real-time operating systems
 * Embedded Control Systems Design/Operating systems -- more real-time operating systems
 * OSDev.org wiki: discusses creating new operating systems
 * Design of Main Memory Database System
 * Distributed Systems

Ontwerp en bouw een besturingssysteem/Inhoudsopgave

title: Operating System Design/Contents


text:
Operating System Design/Case studies

The goal of this book is to discuss the different issues involved in operating system design, the different strategies that have been tried and to provide concrete examples where possible. Given the number of open-source operating systems available, specific implementations will be used as examples where possible.

Example Operating Systems
Naturally, open source operating systems lend themselves to teaching more than proprietary operating systems. The source code of all the following operating systems is available free of charge online:

 * Linux
 * Net/Free/OpenBSD
 * Solaris
 * MINIX
 * GNU Hurd
 * XOK
 * ReactOS

While the following operating systems are closed source, enough is known about their implementation that they can all be used as specific examples of approaches to various OS design issues and tasks.

 * Mac OS X
 * Microsoft Windows 9x
 * Windows NT
 * QNX
 * DOS
 * HP-UX
 * AIX
 * BeOS

Example filesystems

 * FAT
 * NTFS
 * ext4

Case Study Areas
The following areas of operating system design can all be illustrated with specific examples from real operating systems. In some cases different approaches to the same task can be seen within one OS. For example, many operating systems support multiple file system types.

 * Loading the operating system
 * Initialising the operating system for use
 * Managing tasks (processes)
 * Managing memory
 * File systems and storage management
 * User interfaces

For example, in the "Managing tasks" section we might use the example of task management in a single tasking operating system like DOS, as well as some of the different scheduling algorithms that have been used in various multitasking operating systems.

The case study can include comparative analysis about any concept of different operating systems or comparison between the different versions of same operating systems. It can include the total functionality of the operating system given.

title: Operating System Design/Case studies


text:
Talk:Operating System Design/Contents

suggestion
The book contents should be improved in many aspects. I am going to discuss some of them in order to improve the book. Here is the overall material commonly covered in an OS textbook.
 * Introduction and History
 * Process
 * Process Concept
 * Process States
 * Inter Process Communication
 * Process Scheduling
 * Synchronization
 * Deadlock
 * Thread (Light Weight Process)
 * Memory Management
 * Basic Models
 * Virtual Memory
 * Segmentation
 * Paging
 * Filesystem
 * File Abstraction
 * Issues
 * Performance
 * Fault-tolerance
 * Security and Protection

WARNING
Unless somebody objects I am going to hijack this book project and start over. I can't write a complete book on this subject but I can do about 75% and I can provide what I hope is a rational overall structure.

I am much more interested in the history of and rationale for operating systems than I am in the details of the popular contemporary systems. Myself I use Linux these days, but my experience goes back to the ten card loader for the IBM 704.

old stuff
You will find that for a book to be successful it is better to allow people to contribute and colloborate directly - You might find the controversial ASQ page has much of interest for you. Anyway good luck Lobster 12:54, 16 Oct 2004 (UTC)

Thanks, Lobster. I'll change it now. If people want to contribute it would be prefered that they discuss it here first though. Wranga

change title
There are some who feel that a title such as 'my perfect OS' - could not be the title of a text book - (that it is just opinion) so I would suggest giving it some serious title such as "Perfecting Operating System Design" - it sounds silly but these people are control freaks and prefer everyone to conform to their vision limitations - I warn you now :-) Also turn your editing to minor edits as you are still developing the book - good luck :-) Lobster 07:38, 17 Oct 2004 (UTC)

operating system wiki
The TUNES project also involves creating an improved operating system. They have a wiki now:
 * TUNES wiki http://cliki.tunes.org/index

So, does "My Perfect OS" have any new idea that haven't already been discussed to death over on the TUNES wiki ?

Also check out the ideas at
 * Killer Operating System http://c2.com/cgi/wiki?KillerOperatingSystem

ReactOS
ReactOS is almost similar to "My Perfect OS" -- Bijee

Linux Considerations
Requirements to be modular, open, and easy to use are already being rapidly satisfied in many Linux distributions.

Here are a couple of friendly desktops:

 * Ubuntu Linux
 * Morphix - Very modular!

Because Linux is already so advanced, much of the work is already done. Additionally, many linux distributions are accompanied by LiveDistros which give you a full operating system that boots from a cd, dvd, usb stick, or other bootable media devices. These bootable LiveDistros are useful because there are already tools out there to remaster these, giving you your own, unique operating system customized to include your own desktop background, browser bookmarks, applications and more.

Software Analogs
Here's a list of software that is free and can easily be added to My Perfect OS

 * http://www.demosoftware.net/docs/gfdl/equivalents_english_table.html

This is pointless...
This book is pointless, quotes like

"The OS should almost definitely be built upon FreeDOS (http://www.freedos.org/) (or on its 32 bit counterpart, FreeDOS-32 (http://freedos-32.sourceforge.net/)) like Windows 9x is upon MS-DOS. This would enable users to access and maintain and repair their computers when the GUI isn't working."

and

"Linux is best as a server, but average PC users are not familiar with its concepts and simplicity, hence will never be much of a competition to MS Windows."

clearly show that this has been written by a bunch of people too lazy to learn some simple linux command line tools.

go rtfm rather than making up bullshit.

---

While the above user is a wee bit harsh... I see a little truth in it. I don't exactly see where this book is going, nor how I can make this book better. --Dragontamer

ReactOS
You may as well just make a reactos distro reactos.com (they've been having some server problems recently) if your going to clone directx api at least help them do it. they're working on cloning windows itself. (which would make something that's just similary programmed obsolete.)

Where Are MacOS
Where is MacOS i think it was missing!

Embedded Systems
In the Embedded Systems book, We talk alot about Real-Time OS's, and i think that perhaps we could post links between these two books. -- 22:16, 28 November 2005 (UTC)

"< Operating System Design" links point to cover page rather than contents page.
The "< Operating System Design" links point to the cover page rather than the contents page, meaning that people have to click through to the contents page again every time they exit a chapter. Irrevenant 09:05, 24 April 2006 (UTC)

Rearrange Titles
I think this book should have the TOC rearranged some. It's very messy, and does not go in the actual order of development. You SHOULD NOT be working on getting a process into memory UNTIL you have memory management of some type.

Threads versus Processes
A Thread is basically a subset of a Process. Some of the management is removed but generally the same issues exist. Wouldn't the discussion of Threads be better off as a subset of Processes.

The list at the top of this page is a decent start, but omits Initialisation. The order of topics being covered can vary depending on whether you want to go through order of development, or order of running, but the basics that should be covered are:
 * Initialisation
 * Boot Loaders (including multi stage ones)
 * Hardware Initialisation (after the OS has loaded)
 * Tasks (Processes if you prefer)
 * Definition
 * Scheduling
 * First Come First Served
 * Run Shortest First
 * Run First to Complete
 * Time slicing
 * Pre-emption
 * Prioritising
 * Concurrent processing
 * Deadlock
 * Livelock
 * Interprocess Communication
 * Semaphores
 * Shared Memory
 * Threads (Lightweight processes)
 * Memory Management
 * Basics
 * Allocation Algorithms
 * Segmentation
 * Virtual Memory
 * Paging
 * Swapping
 * Fault Tolerance (Page Deallocation tables)
 * File Systems
 * Abstractions
 * Allocation Algorithms
 * Performance
 * Fault Tolerance
 * RAID
 * Moving Bad Blocks
 * Journalling
 * Security
 * Access Controls
 * Users
 * Resources
 * Privileges

Continuing Work
I see that some edits have been done... I've tried to tidy some of the pages up a bit, and mostly I'm working from memory here so if I make mistakes please correct me. It seems like some of the pieces that have been added are very minor, but still if we can get some more pages in place perhaps we can make this actually useful...

I've not added any specific implementation chunks in as I'm not sure what the best way to do it would be... Explicit copies of portions of Open OSes that match the descriptions, or custom pseudocode that at least helps the would be learner to understand what they would need to write? Any thoughts any one? --Zwack 17:51, 28 October 2007 (UTC)

title: Talk:Operating System Design/Contents


text:
User:Gary King

Hi there! Nothing much to see here, so move along now!

title: User:Gary King


text:
User talk:Gary King

Hello, talk all you want!

Rename Request
Hello,. I've received your rename request. Here is what I need from you:

Once you have satisfied these requirements, send me a message and I can rename you. If you have any questions, or if you need any help, you can ask me on my user talk page, or you can ask the community at WB:CHAT or WB:AN. --Whiteknight (Page) (Talk) 03:09, 18 April 2008 (UTC)

title: User talk:Gary King


text:
Meeting Basics

 * /Introduction/
 * /Preparation/
 * /The Meeting/
 * /Follow-Up/
 * /Resources/

title: Meeting Basics


text:
Meeting Basics/Introduction

If you participate in a sports team, play music in a group, organize a group of neighbors to convince local government to plant a tree in your street or  work with colleagues in a project, in all these situations you will have to make decisions together, inform each other and distribute the work to be done. To do these things you will have to get together from time to time and have a meeting. This booklet describes a structure you can give to your meetings.

If you have to meet with more than twenty-five people the structures described in this booklet become impractical and might lead to fruitless meetings without end. For such meetings it is better to borrow ideas from regulations as they are used for member participation in parliaments and large societies. If you meet with two or three people, probably no formal structure will be needed. If you meet with four to twenty people and the task is complicated or will span a significant amount of time, having a meeting as described in this booklet is probably a good option and this booklet is written for you.

Tip
In your opening meeting if you run a brainstorming session (maybe on a whiteboard) and ask people what they want from a good meeting, you inevitably get a list reflecting your objectives but you've created much greater buy-in from your team. Buying early makes the whole process easier.

title: Meeting Basics/Introduction


text:
Internet Technologies/Web advertising

Web Advertising uses static images, animated GIFs, and Flash Animation to display a product or service. Advertising on the Web displays in many different ways such as banners or buttons, Pop-up and Pop-under, and intro pages to websites.

A banner or a button can be an image, animated gif, flash video or plain text

A Pop-up or Pop-under causes a new browser window to open and displays a webpage that can contain text, images and flash.

Intro Pages to websites usually have a flash or gif animation to introduce a company, their services or Products.

Internet advertising is delivered by ad servers. The most common type of ad server in use today is the Central ad server.

Standard Sizes for Banner Style Advertisements are as follows:

Rectangles -

300x250 250x250 240x400 336x280 180x150

Banners -

468x60 234x60 88x31 120x90 120x240 125x125 728x90

Skyscrapers -

160x600 120x600 300x600

title: Internet Technologies/Web advertising


text:
User talk:IBB~enwikibooks

As I stole most of my style sheet from other editors, feel free to use it all you want. :) I'm glad someone else likes it. Oh, as I seem to be the first one here, Welcome to wikibooks.  If you have any questions, feel free to ask at the Staff lounge, or ask me on my talk page. Gentgeen 19:13, 16 Oct 2004 (UTC)
 * oh, by the way, if you want to have little tabs at the bottom of the page, you need to copy the content of User:Gentgeen/monobook.js into User:IBB/monobook.js, and have java script enabled in your browser. There are also some problems with a few browsers displaying the bottom tabs, but I can't remember what they are.  Good luck. Gentgeen
 * Thanks for the welcome :) IBB 13:47, 22 Oct 2004 (UTC)

Your account will be renamed
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Unfortunately, your account clashes with another account also called IBB. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name IBB~enwikibooks that only you will have. If you like it, you don't have to do anything. If you do not like it, you can pick out a different name.

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Renamed
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title: User talk:IBB~enwikibooks


text:
Meeting Basics/Preparation

Agenda
A good agenda reflects the function of the meeting, because many of these functions are the same for any group staying together for a longer time a large part of the agenda can exist of standing items. An example may clarify this, many companies in Europe have a workscouncil from which representatives of the employees give advice to the management of their company. Their agenda might look something like this:

Agenda Workscouncil YourCompany

Date: 2004 October 16

Time: 11.15

Location: YourCompany Headquarters, Meeting Room 1

Why is this agenda as it is? The order is rational, as we hope to show.
 * 1) Opening and Agenda
 * 2) Minutes Last Meeting
 * 3) Open Action Points
 * 4) Incoming Mail
 * 5) Outgoing Mail
 * 6) Implementation New Tax Rules on Company Cars for Private Use
 * 7) *Backgound: See IN2004-078, Finance Ministry, Tax Guide 2004
 * 8) *Proposal : See Attachment: P2004-10: "Ads on Our Cars to Keep YourCompany Rolling." The Chairman of our finance committee will present the proposal.
 * 9) Communication with Employees
 * 10) * Background: Via several routes complaints have reached the workscouncil that employees feel they don't get sufficient information on workscouncil matters. Proposal: The Chairman and two members (who?) will contribute a page to our company magazine and add a news section to the workscouncil website.
 * 11) Committee Updates
 * 12) Social Policies Committee
 * 13) New Child Care Provider
 * 14) New Year Party
 * 15) Work Conditions Committee
 * 16) Safety Inventory 2005
 * 17) Preparation Meeting with Management
 * 18) *Background: Management proposed agenda points see IN2004-201.
 * 19) Roundtable
 * 20) Closure

Date, Time, Location
Well should we explain this? We suppose you would like the participants to be at the meeting. Therefore, we recommend to add these items to the agenda. Only change the date or time after sending out the agenda if you discover there is something important (a festival, a sports game, etc.) at the planned time that will stop a majority of the participants from coming to the meeting. Of course it is better if you are able to check for these obstacles in advance.

Opening and Agenda
Opening, this is often nothing more then a welcome to all participants. If there are new participants or it is the first meeting those new participants can be introduced here. The opening can however be a place to add a small identity related element. In the case of the workscouncil this does not apply, but the board of a poetry society could start every meeting with a poem.

Agenda, fix it well before the meeting, as an agenda point it is there as a last resort to make a change. Although there might be a reason to add or remove an agenda point, changes to the agenda should be a rare exception rather than the rule. To have an agenda point added during the meeting it should be very urgent, because most participants did not get a chance to inform themselves and will therefore not be able to participate with judgement in the discussion. If adding an agenda point is necessary it should probably be combined with a break in which the participants can prepare themselves.Removing an agenda point during the meeting can be an option if changes have removed the necessity of discussing it or if there is reason to assume there will be no time to deal with it. Even changes to an existing agenda before the meeting should be discouraged, because even if sent to the participants by mail or email these changes often fail to reach them, because they have developed habits of reading their mail only at certain time or simply because they have limited access to them.

Minutes Last Meeting
An opportunity to correct factual mistakes in the minutes of the previous meeting. Not an opportunity to restart discussions. These days the best way to deal with minutes is probably more direct: The minute taker can send the minutes to the participants as soon as possible after the meeting and gives the participants to point factual mistakes. After that the corrected minutes can be sent with the agenda.

Open Action Points
A list of things to be done, the list should at least indicate: what, when and who. This is the moment to indicate which points can be closed and to consider whether a task should be tranferred from one participant to another. For this agenda we assumed it is provided as an attachment, but if the list is short it can be simply included. The list is there to prevent the meetings from turning into a tea party, i.e. a gathering of people talking about the work without ever getting it done. Because this list shows which participants are performing the work it is also a useful instrument in getting everybody to take a fair share in the work.

Incoming Mail
A list of incoming mail, it is there to inform all participants, if they are interested they can pay a visit to the mail archive to have a look at the mail. The list should at least include the day it was received, who sent it and a short description of the content. The person making the agenda should go through the mail before making the agenda to see if anything needs to be addressed in the meeting. Because the person making the agenda has to go through the mail and also send the material for the meeting of to the participants, responsibility for handling correspondence is often put in his/her hands aswell.

Outgoing Mail
A list of outgoing mail. Participants should be informed about the mail that is sent on their behalf as well. The list should at least include when correspondence was sent, to whom and a short description. Again of every item on this list a copy should be available in the mail archive. If it contains useful information a copy of an important letter can be sent to all participants to whom the content is relevant.

Variable Agenda Points
In this agenda there are three of them. These are generally considered to be the main part of the meeting. If most time is spent on other agenda points, the agenda was probably not optimal or the chairman incapable of leading the meeting correctly or the participants not sufficiently disciplined to follow the chairman.

Because it is likely that an update from the committees is important for the meeting with management, the committee update is put before discussing the meeting with management. Generally, however, one would keep the non-standard agenda points together.

What are the important points to notice about these agenda points. First they indicate where you can find new relevant information or they give a short description it. Second they indicate a direction for solving the problem.

The relevant information can come from all kind of sources, for the agenda point `New Tax Rules on Company Cars for Private Use' this is an incoming piece of mail IN2004-78 ( this is the number by which you can find it in the archive) sent by the finance ministry containing an update on tax rules. In the ideal case the finance committee noticed the problem at the same time as management did and the proposal on the agenda was reached by a collaboration between management and the finance committee. In practice howevere there might reasons, good or bad, why such a collaboration with people outside is not possible and the proposal your group makes needs to negotiated with the other party. The proposal accepted in the meeting is then still subject to negotiations and might actually contain suggestions for a negotiation strategy aswell. For the agenda point `Communication with Employees' it is simply a remark which summarizes employee opinions that reached the workscouncil over the past few months, be it by email, mail or conversations. For the agenda point `Preparation Meeting with Management' it is a proposal for an agenda meeting sent by management. If management thinks the new tax rules are the employees problem they will not put it on the agenda and leave it to the alertness of the employees. If on the contrary they have already reached preliminary agreement with the finance committee they probably want to get it on the agenda so they can obtain certainty and can plan the work related to it. This is an important point about agenda's: in general the agenda points left out can convey at lot of information about the goals are of the agenda maker.

The proposals also vary a lot in style and detail. For the changing tax regulations it is a complete document  which will also be further explained by the finance committees chairman. For the communication problems it is very simple and concrete and the main problem left is to find people who are willing and able to do it among the participants. For the agenda for the meeting with management, there is the managements proposal but no internal proposal. There are two good reasons not to have an internal proposal yet: first the proposal by management will probably have most of the agenda points the workscouncil would come forward with and therefore changing it will be amending it, secondly probably only after dealing with the previous agenda points will it be clear which agenda points need to be added. It is a general rule of politeness to accept agenda points put forward by the other party and only add new agenda points. If this leads to time or other problems it is a good idea to ask the chairman or another participant who can act on behalf of the whole group to contact the chairman of the other group, in this case management, about the agenda.

Committees
Committees are an important instrument to structure work and we will come back to them. A meeting is often not the right place to do the real work, that is why this work is sometimes delegated to a committee. Many organizations, like the workcouncil in our example, often have permanent committees, because they are permanent they function largely independently but need to be able to report on the work they do. Because the end responsibility stays with the participants of the meeting they need to be able to judge the work of the committee and sometimes even confirm the decisions or decide between proposed alternatives.

Roundtable
An opportunity for all participants to briefly share factual information with all other participants. This is not a place for discussion!

Closure
Mostly a simple thank you and see you next time by the chairman, but see remarks made about the opening. This is also the right place to thank leaving participants and give them flowers.

=Participants=

Who should be invited for the meeting?

1. Everybody who by regulation has a right to be at the meeting.

These people should all be informed timely that a meeting is taking place and about what is on the agenda. If there are many people who have a right to be at the meeting but in practice they rarely do, this information should be sufficient. You will have to provide a place where they can access the relevant information. If this a situation that applies it is good practice to make a strict rule where and when you announce the meeting, especially if you don't know who these people are. If this group is small and practically everybody is always present it is easier to send the preparation material to all possible participants.

2. Everybody who by regulation is required or at least expected to be at the meeting.

These people all receive an agenda and the relevant background material and proposals. Where it should be noted that generally most incoming and outgoing mail is not relevant to the meeting!

3. People who need to give information to the meeting in person.

The works council meeting above mentions committee updates, if the committee member who is most suited to give the update is not a regular participant in the meeting this expert committee member can be invited for the committee update. If the other agenda points are not confidential or even stronger the meeting is public, then this guest can be allowed to be there for the whole meeting. If there are agenda points where the guest presence is not desired and the meeting is not public the guest can simply be called in for the one agenda point in which he gives information. In the case of an works council meeting is conceivable, although more likely to happen in a committee, that a Human Resources officer comes to explain a certain regulation. The role of the Human Resources officer is to support management, because of that one doesn't want to discuss a negotiation strategy in the his/her presence. Another example to explain this: if your society is in conflict with local government over a permit for adding a kitchen to your society building but you found a civil servant who is willing to explain the new subsidy regulations to you, it is better not to discuss the kitchen problem in his presence. Even if you know this civil servant can be trusted it is better not to put the loyalty conflict on him.

Who should not be invited?

1. Individuals with whom your organization or group has a conflict.

A meeting of your own group is not the place to solve a conflict with an individual, be it someone from outside or inside. It is better to talk to such an individual with a small number of people, where a small number is one or two and definitely not three. And two is really the best.

2. The Opponent in Negotiations.

Well this is almost trivial. However be aware of the third category of people that should be invited. Reality is seldom black and white and where you might have hard negotiations on some topics you might have peaceful cooperation with the same outside group on others topics. This leads to another important point to make about opponents in negotiations, it is important not to spoil personal relationships with people in the other group, so try to keep conflicts purely business.

Invitation
To get the participants to the meeting they need to be invited, or if an appointment was made at a previous meeting or via telephone they still need to receive an agenda and supplementary documents.

For small and/or well defined groups invitation, agenda and all other documents should be sent at least a week in advance of the meeting to all participants. If the group is very small, the meeting takes place at a fixed time and the participants agree to it you can shorten this period, but in all other situations a week is an absolute minimum. Of course if the meeting takes place every week, there is no other option but sending the agenda and documents at shorter notice.

For large and/or not well defined groups other methods apply, a possibility is to approach them through local papers, a poster in your street or apartment building. For these groups you should think about a creative way to approach them but always stay polite. If you don't know precisely who will be attending, you will have to start early with making announcements.

Don't forget to invite the guest partipants and to indicate to them when and where they are expected to join the meeting.

title: Meeting Basics/Preparation


text:
JLPT Guide/JLPT N5 Vocabulary/Row Ka

Vocabulary words for the Japanese Language Proficiency Test starting with かーこ.

title: JLPT Guide/JLPT N5 Vocabulary/Row Ka


text:
JLPT Guide/JLPT N5 Vocabulary/Row Sa

Vocabulary words for the Japanese Language Proficiency Test starting with さーそ.

title: JLPT Guide/JLPT N5 Vocabulary/Row Sa


text:
JLPT Guide/JLPT N5 Vocabulary/Row Ta

Vocabulary words for the Japanese Language Proficiency Test starting with たーと.

title: JLPT Guide/JLPT N5 Vocabulary/Row Ta


text:
JLPT Guide/JLPT N5 Vocabulary/Row Na

Vocabulary words for the Japanese Language Proficiency Test starting with なーの.

title: JLPT Guide/JLPT N5 Vocabulary/Row Na


text:
JLPT Guide/JLPT N5 Vocabulary/Row Ha

Vocabulary words for the Japanese Language Proficiency Test starting with はーほ.

title: JLPT Guide/JLPT N5 Vocabulary/Row Ha


text:
JLPT Guide/JLPT N5 Vocabulary/Row Ma

Vocabulary words for the Japanese Language Proficiency Test starting with まーも.

title: JLPT Guide/JLPT N5 Vocabulary/Row Ma


text:
JLPT Guide/JLPT N5 Vocabulary/Row Ya

Vocabulary words for the Japanese Language Proficiency Test starting with やーよ.

title: JLPT Guide/JLPT N5 Vocabulary/Row Ya


text:
JLPT Guide/JLPT N5 Vocabulary/Row Ra

Vocabulary words for the Japanese Language Proficiency Test starting with らーろ.

title: JLPT Guide/JLPT N5 Vocabulary/Row Ra


text:
JLPT Guide/JLPT N5 Vocabulary/Row Wa

Vocabulary words for the Japanese Language Proficiency Test starting with わーを.

title: JLPT Guide/JLPT N5 Vocabulary/Row Wa


text: Template:Japanese/Parts of speech

title: Template:Japanese/Parts of speech


text:
Operating System Design/Graphical user interfaces

GUIs display visual elements such as icons, windows, and other gadgets. The precursor to GUIs was invented by researchers at the Stanford Research Institute (led by Doug Engelbart) with the development and use of text-based hyperlinks manipulated with a mouse for the On-Line System. The concept of hyperlinks was further refined and extended to graphics by researchers at Xerox PARC, who went beyond text-based hyperlinks and used GUIs as the primary interface for the Xerox Alto computer. Most modern general-purpose GUIs are derived from this system. For this reason some people call this class of interface a PARC User Interface (PUI) (note that PUI is also an acronym for perceptual user interface). The PUI consists of graphical widgets (often provided by widget toolkit libraries) such as windows, menus, radio buttons, check boxes, and icons, and employs a pointing device (such as a mouse, trackball, or touchscreen) in addition to a keyboard. Those aspects of PUIs can be emphasized by using the alternative acronym WIMP, which stands for Windows, Icons, Menus, and Pointing device.

The GUI familiar to most of us today in either the Mac or the Windows operating systems and their applications originated at the Xerox Palo Alto Research Laboratory in the late 1970s. Apple used it in their first Macintosh computers, followed by Atari with their ST range, and Commodore with the Amiga. Later, Microsoft used many of the same ideas in their first version of the Windows operating system for IBM-compatible PCs. Examples of systems that support GUIs are Mac OS, Microsoft Windows, NEXTSTEP and the X Window System. The latter is extended with toolkits such as Motif (CDE), Qt (KDE) and GTK+ (GNOME).

Types of GUIs
GUIs that are not PUIs are most notably found in computer games, and advanced GUIs based on virtual reality are now frequently found in research. Many research groups in North America and Europe are currently working on the Zooming User Interface or ZUI, which is a logical advancement on the GUI, blending some 3D movement with 2D or "2 and a half D" vectorial objects. Some GUIs are designed for the rigorous requirements of vertical markets. These are known as "application specific GUIs." One example of such an application specific GUI is the now familiar touchscreen point of sale software found in restaurants worldwide and being introduced into self-service retail checkouts. First pioneered by Gene Mosher on the Atari ST computer in 1986, the application specific touchscreen GUI has spearheaded a worldwide revolution in the use of computers throughout the food & beverage industry and in general retail. Other examples of application specific touchscreen GUIs include the most recent automatic teller machines, airline self-ticketing, information kiosks and the monitor/control screens in embedded industrial applications which employ a real time operating system (RTOS). The latest cell phones and handheld game systems also employ application specific touchscreen GUIs.

GUI vs. CLI
GUIs were introduced in reaction to the steep learning curve of Command Line Interfaces (CLI), text-based user interfaces requiring commands to be typed on the keyboard. Since the command words in CLIs are usually numerous and composable, very complicated operations can be invoked using a relatively short sequence of words and symbols. This leads to high levels of efficiency once the many commands are learned, but reaching this level can take a while because the command words aren't easily discoverable. WIMPs, on the other hand, present the user with numerous widgets that represent and can trigger some of the system's available commands. Most modern operating systems provide both a GUI and a CLI, although the GUIs usually receive more attention. The GUI is usually WIMP-based, although occasionally other metaphors surface, such as Microsoft Bob, 3dwm or (partially) FSV. Applications may also provide both interfaces, and when they do the GUI is usually a WIMP wrapper around the CLI version. The latter used to be implemented first because it allowed the developers to focus exclusively on their product's functionality without bothering about interface details such as designing icons and placing buttons. Nowadays, the GUI is no longer considered an optional part of most applications because users have grown accustomed to the ease of use provided by their familiar GUIs.