Outbound Message & Attachment

Question: Is it possible to send an uploaded file (attachment) to an Enterprise Server via an Outbound Message?
Answer: Even if you could add an attachment to the message you wouldn't be able to use anything in the standard UI to be able to find the appropriate file. Your best bet here would be to use Apex to make the callout to the remote service, activating it either via a trigger on attachment if that's what you're using, or possibly from a VisualForce page where you use an <apex:inputFile> element to facilitate the upload part.
I can't really be more specific without more details but hopefully this will get you headed in the right direction.

Outbound Message & Attachment


Maven Compile Plugin finds the dependencies but Maven Javadoc Plugin doesn't

Question: I try to generate the Java API documentation of a project composed of multiple sub-modules with mvn site but it doesn't work whereas mvn install works, it resolves all dependencies and it compiles successfully. mvn site resolves neither the dependencies that are inherited by all sub-modules in the parent pom file (including easymock) nor the dependencies specific to some sub-modules (including SWT).
I obtain the following error message:
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-site-plugin:3.7.1:site (default-site) on project ardor3d: Error generating maven-javadoc-plugin:3.1.1:aggregate report:
[ERROR] Exit code: 1 - /home/gouessej/Documents/programming/java/workspace/Ardor3D/ardor3d-swt/src/test/java/com/ardor3d/input/swt/TestSwtMouseWrapper.java:23: error: package org.eclipse.swt.events does not exist
I use Maven 3.6.1 with OpenJDK 11. This problem concerns the open source project JogAmp's Ardor3D Continuation and is reproducible with the latest source code.
I saw a similar question here but I don't think that the accepted answer helps in my case.
It worked with Java 8 but I'm not sure that it's the culprit.
P.S: Reverting this change and using Java 8 work around this bug.
Answer: Replacing <release>8</release> by <source>1.8</source><target>1.8</target> and using Java 8 instead of Java 11 solve the problem. It's probably a bug of maven-javadoc-plugin with Java 11. This bug has been reported here.


How to make text layer spot channel in photoshop?

Question: I am working with a UV printer which requires my white colour on Photoshop to be on a spot channel. What is the correct way to convert a text layer into a spot channel? It seems that to make it spot, it becomes a selection which means I can no longer change the text.
Comment: A spot colour can't be applied to an editable text layer in Photoshop. Channels in Photoshop are raster only. Better to do this in Illustrator or InDesign. Import any raster image you need, then type some text on top, set the text colour to a spot colour.  The text will still be editable. If you don't have access to these, it could also be done in Scribus, which is like InDesign, and supports spot colours.
Answer: You are correct. Spot channels can not contain live, editable text. One creates a selection based upon text, then fills the spot channel based upon the selection. Then hides the text layer.
This is a partial reason a 2-file workflow is desired, if not required. One file containing all the layers for construction. Then another file that's been flattened for reproduction. This way you have a working file so you can redo some steps should things like text need to be changed in the future.


Persistence: ManyToMany to same class

Question: I am trying to set a ManyToMany annotation on my code:
<code>@Entity
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@Table(name = "user")
public class User extends AbstractUser
{

    @ManyToMany(mappedBy = "promotors", cascade = CascadeType.PERSIST)
    @JoinTable(name = "user_student",
        joinColumns=@JoinColumn(name="promotor_id", referencedColumnName="id"),
        inverseJoinColumns=@JoinColumn(name="student_id", referencedColumnName="id")
    )
    private Collection<User> students;

    @ManyToMany
    private Collection<User> promotors;
}
</code>
However every time i try to run the application and the db gets generated, it creates 2 tables for the ManyToMany, 1 new table that is called user_student as i defined beneath, but it also creates a second table user_user which i didn't define but is generated from the promotors.
Answer: It's correct you cannot map many to many relationship on one table. As you have only one possible column to map it to. What enforces one to one relationship.
You always have to have mapping table. Its also most convenient way to map many to many relationships on different tables.
Comment: Yes i know that, however here it creates 2 tables and it should only create 1 extra table, called user_student. For some reason it also creates a table user_user
Answer: Apparently, i didn't define the second ManyToMany correctly, this is the correct code:
<code>@Entity
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@Table(name = "user")
public class User extends AbstractUser
{

    @ManyToMany
    @JoinTable(name = "user_student",
        joinColumns={@JoinColumn(name="promotor_id", referencedColumnName="id")},
        inverseJoinColumns={@JoinColumn(name="student_id", referencedColumnName="id")}
    )
    private Collection<User> students;

    @ManyToMany(mappedBy = "students", cascade = CascadeType.PERSIST)
    private Collection<User> promotors;
}
</code>

Persistence: ManyToMany to same class


tips for plastic material not to look like glass vial

Question: Here is the blend file:
So I've been looking everywhere for a way to make this bottle and nozzle cap look as close to the real version as possible. I've used many different node setups I've found online to see it on my model, but I can't seem to get the same look as the real bottle. I hate to sound like I'm wanting anyone else to do the work for me, but I've never really used node for anything other than applying PBR textures. I tried changing the transmission value and adjusting the roughness, but it just seems like glass. Maybe I should remove the thickness of the bottle, so the fluid inside will look like it does in real life, but I used reference photos to make the model as accurate as possible. I just assume transparent plastic is tricky.
Real bottle

My model
Answer: I think you can get away with a much simpler node setup. Try something like this:
Comment: Wow! Thank you, that does look better for the nozzle. But I was meaning the bottle itself. Sorry if my question was confusing. But your nozzle nodes look better. Should I use the same nodes and just change some of it for the bottle part?
Comment: Oh. Sorry if I misunderstood, it's just that the bottle looks like pure glass in your reference image.. Byt, yeah, it should work for the whole bottle.
Comment: I think my issue for my bottle is that I gave it thickness. I did that because I plan to turn the fluid into real fluid later for an animation and the last time I tried to use fluid it leaked through my object, so I gave up.
Comment: No, you are correct. If you make a bottle with no thickness to the outer faces (just one hollow object), and attempt to use any shader that resembles glass, or has refraction (Fresnel/IOR, etc...) blender will interpret it as being solid (ie. a hollow sphere will become a solid glass ball with a glass shader). Because you want your bottle to appear as "empty" in the middle (so it can be filled with liquid), it's good you gave the bottle thickness. Maybe just a bit too thick (although more thickness is always better when containing physics sims including liquid.).
Answer:
I think for the proper plastic, you play with mixes here of translucency volume scatter and glass. for glass the ior has a huge effect on the reflections (remind plastic has higher IOR usually).
But also important is to have some background for the glass to reflect something, i added one, a few more tiny tricks in it as well, adding a light with a shader to get more play in the light, its subtile
also the color of the light isnt white.
and I scaled the purple part a bit.
if you like to check here are the shaders:
if you like the screw-glass part to be more white on top, add some white object above it (make a light studio environment), so then its possible to reflect that.
Answer: Tried @Christopher's solutions and the shader looks good to me. I made my own approach:

I used a Principled shader, see image
I changed the model a bit, reduced the thickness of the bottle and scaled the fluid up
I added transluceny and subsurface to the fluid shader.
Comment: I like how the fluid part looks better in your results. Would it be ok if I get the blend file, so I can compare it to mine and see exactly how you made your changes to learn from it.
Comment: How thick did you make the bottle


How to prove this simple limit?

Question: Let $f:[0,+\infty]\to R^1$ to be a function which satisfies the following properties.
$$ $$
1.$f$ is uniformly continuous on $[0,+\infty)$
$$ $$
2.For any $x_0\in[0,1]$,we always have $\lim_{n\to+\infty}f(x_0+n)=0$
$$ $$
Please find $\lim_{x\to+\infty}f(x)$.
$$ $$
It's obvious to know that the limit is zero, but my question is how to use mathematics language to prove instead of my intuition. Is there any definition or  theorem that I can apply to solve this? (A hint would be grateful.)
Comment: What does it mean by $R^1?$@Chiu-Tzu-Hsuan
Comment: @diya
it means its domain is from 0 to $\infty$ in real space with dimension 1
Answer: Fix $\varepsilon>0$. Since $f$ is uniformly continuous on $\left[0,\infty\right)$, there is some $\delta>0$ such that if $\left|x_1-x_2\right|<\delta$, we have $\left|f\left(x_1\right)-f\left(x_2\right)\right|<\frac{\varepsilon}{2}$.
Now the idea is to take $m\in\mathbb{N}$ such that $m>\frac{1}{\delta}$, and by the uniform continuity, the value of $f$ at a point $x\in\mathbb{R}$ can be "approximated" by $f\left(\frac{k}{m}+n\right)$ for appropriate $k=0,\dots,m-1$ and $n$. We only need to choose $n=\left\lfloor x\right\rfloor$ and $k$ such that $\left|\frac{k}{m}+n-x\right|<\frac{1}{m}<\delta$.
Now you can work directly with the definition of convergence. Try to continue on your own.
Answer: We can use the definition of limit and prove that for every $\epsilon>0$ there exists $M>0$ such that $|f(x)|<\epsilon$ when $x>M$. So let's fix $\epsilon>0$, since $f$ is uniformly continuous, there is a $\delta>0$ such that $|f(x)-f(y)<\epsilon/2$ if $|x-y|<\delta$. Now divide the interval $[0,1]$ in $m$ intervals of lenght $1/m$ so that $1/m \le \delta$ : $[0=x_0,x_1],[x_1x_2],...,[x_{m-1},x_n=1]$. By hypothesis 2) we know that for every $x_i$ there exists $M_i>0$ such that $|f(x_i+M_i)|<\epsilon/2$ for every $n>M_i$. Take
$$M=\max M_i+1.$$ This works because if you choose $x>M$, then $x-\lfloor x \rfloor \in [0,1]$, in particular $x-\lfloor x \rfloor \in [x_i,x_{i+1}]$ for some $i$. Hence $|f(x_i+\lfloor x \rfloor)|<\epsilon/2$, because $\lfloor x \rfloor\ge M>M_i$, and so
$$|f(x)|\le |f(x_i+\lfloor x \rfloor)|+\epsilon/2\le\epsilon$$
because $|x-(x_i+\lfloor x \rfloor)|=|x-\lfloor x \rfloor-x_i|<1/m \le \delta$.

How to prove this simple limit?


Why were Dumbledore and Ron so angry at Harry?

Question: Why were Dumbledore and Ron so angry with Harry when his name appeared in the Goblet of Fire? These two people had never questioned him before so why did they suddenly become enraged at him?
Comment: You may want to clarify if you are asking about the movie; Dumbledore wasn't angry in the book.  This rather struck me as jarring in the movie, as it seemed very out of character for Dumbledore.
Comment: Funny, I just watched the RiffTrax of Goblet of Fire again last night and was astounded by how unreasonably angry Ron was with Harry. Strange coincidence. I think it's a reasonable and easily understandable question, especially given Harry's saving of the school / students so many times. This TriWizard Cup hostility seems almost nonsensical. At least from Ron. Albus may have just been mad at the situation, his magic being thwarted and all. I'll do a minor edit, and vote to reopen.
Answer: I don't remember what happen in the movie but in the book Dumbledore was calm.

"Did you put your name into the Goblet of Fire, Harry?" he asked calmly.
"No," said Harry. He was very aware of everybody watching him closely. Snape made a soft noise of impatient disbelief in the shadows.
"Did you ask an older student to put it into the Goblet of Fire for you?" said Professor Dumbledore, ignoring Snape.
"No," said Harry vehemently.
Harry Potter and the Goblet of Fire, Chapter 17, The Four Champions

I think Hermione explains Ron's reaction very well, when she says

"Oh Harry, isn't it obvious?" Hermione said despairingly. "He's jealous!"
"Jealous?" Harry said incredulously. "Jealous of what? He wants to make a prat of himself in front of the whole school, does he?"
"Look," said Hermione patiently, "it's always you who gets all the attention, you know it is. I know it's not your fault," she added quickly, seeing Harry open his mouth furiously. "I know you don't ask for it... but - well - you know, Ron's got all those brothers to compete against at home, and you're his best friend, and you're really famous - he's always shunted to one side whenever people see you, and he puts up with it, and he never mentions it, but I suppose this is just one time too many...
Harry Potter and the Goblet of Fire, Chapter 18, The Weighing of the Wands

There are other reasons, because this was the first time Ron wasn't involved in Harry's adventure.
1. Harry Potter and the Sorcerer's Stone: Ron won 50 points for Gryffindor

"First — to Mr. Ronald Weasley..."
Ron went purple in the face; he looked like a radish with a bad sunburn.
"... for the best-played game of chess Hogwarts has seen in many years, I award Gryffindor house fifty points."
Harry Potter and the Sorcerer's Stone, Chapter 17, The Man With Two Faces

2. Harry Potter and the Chamber of Secrets: Ron won Special Awards and 200 points for Gryffindor

"You will both receive Special Awards for Services to the School and — let me see — yes, I think two hundred points apiece for Gryffindor."
Harry Potter and the Chamber of Secrets, Chapter 18, Dobby's Reward

3. Harry Potter and the Prisoner of Azkaban: Managed to beat the Ministry of Magic and Saved Sirius Black
Now look at it from Ron's perspective, his best friend found a way to become second champion of Hogwarts but Harry did not help him become a champion nor did Harry bother informing him. As a friend who stood by Harry to fight Voldemort, Lupin (when he was werewolf) and the Dementors, Ron naturally felt let down by Harry.
Comment: "I don't remember what happen in the movie but in the book Dumbledore was calm." The exact opposite of what happened in the book is what happened in the movie.  Ridiculous.
Comment: @Kevin The view would improve things since the scene referenced I feel goes completely against the Dumbledore character. There is a reason that scene is widely mocked http://cdn.slowrobot.com/4212013014012.gif - now you can say the movies and the books are on a separate continuity but it's still ridiculous in my opinion.
Comment: This question had me watching the Goblet of Fire, I agree with @Dason the scene goes against Dumbledore's nature. The only time I remember Dumbledore was agree when he realizes Barty Crouch Jr. was pretending to be Alastor Moody.
Comment: @Dason: Personally, I'm of the opinion that the movies make more sense as a separate continuity from the books.  I mean, they're clearly set in a different time period, for one thing.
Comment: Ron played a pretty small role in the final events of *Prisoner of Azkaban* too. Other than that, solid answer.
Comment: Ron stayed out of the final act of Prisoner of Azkaban because he was unconscious but in a small way he was part of the action. In this case he felt completely sidelined.
Comment: I think it should be broudly noted that the dumlbledore in the movies barely resembles the dumbledore in the books. Losing Richard Harris although tragic in its own, was a tragedy for the Harry Potter movies as well. Richard Harris embodied the spirit of dumbledore so very very well.
Comment: @Vishvesh Also when he shows up to the Department of Mysteries. "Directly above
them, framed in the doorway from the Brain Room, stood Albus
Dumbledore, his wand aloft, his face white and furious."
Comment: It comes down to the actor not reading the books and wanting to play the character his way. https://www.telegraph.co.uk/culture/harry-potter/6216415/Sir-Michael-Gambon-has-never-read-Harry-Potter.html
Answer: Ron is one of many siblings, so he was probably often overlooked.  He saw the Tournament as a chance at glory, and was so angry at Harry for (apparently) finding a way around Dumbledore's spell and not sharing it with his best friend.  He actually says this second part when the two make peace.
As for Dumbledore, I think rather than anger, Dumbledore's attitude was out of worry and alarm and a little anger that maybe Harry DID put his own name in the cup somehow.  I say 'I think' but Dumbledore's love for Harry and concern for him throughout the series supports my reasoning.  Dumbledore knew what the Tournament is like and - like a parent - was deeply concerned for Harry going through it, and that he'd possibly fallen prey to a devious act (someone putting his name in the cup with ill intent), plus what he would face in the coming years: Voldemort and the Horcruxes (Albus already knew or suspected all this, as explained in Half-Blood Prince).
Answer: Ah... it's funny how much the movies change that scene. Dumbledore was calm the entire time in the books; he simply calmly asks Harry the obvious questions to convince Karkaroff and the other non-believers. Also, he wasn't angry with him in the slightest.
As for Ron? Ron was probably feeling left out and his insecurities over being "overshadowed" got the worse of him and he thought Harry had somehow put his name into the goblet without telling him. Hermione was not completely right about him being jealous either, because Ron has had plenty such instances and he's only usually been happy for Harry. While the movies were mostly right about Ron's reaction, they were so hilariously wrong about Dumbledore's the scene actually made me laugh.  Because the entire time, Dumbledore was practically in Harry's face interrogating him, when he was supposed to be calm.
Answer: Dumbledore was angry because the script-writers decided to change book canon into an absurd out-of-character outburst by movie-Dumbledore.
Ron was angry because he believed Harry had gone behind his back to put his name in the Goblet. He felt Harry should have told him and taken him along so he could have put his name in too. Ron was upset that it was always Harry in the spotlight, never him.
Comment: How is this different than the existing answer?
Comment: @Catija The fact that Ron accused Harry of not taking him along when he (supposedly)snuck his name into the Goblet? I didn't back it up with a quote, but that's definitely new.
Answer: The reason they are angry is because Ron is poor and sees Harry as his support because he is a middle child. I mean Ron is a middle child so forcing his friendship on Harry he can be seen as a strong support of TBHL (The Boy Who Lived) not just a moral friend.
Dumbledore likely planned it happening or had some foreknowledge as he usually keeps things a lot from Harry in order to test his growth as Harry is a weapon to Dumbledore so Dumbledore shows no favoritism.  Dumbledore has a bad history of refusing to believe he can make wrong decisions and it has cost him his staff and students whom are close to him.
Comment: Welcome to SFF.SE! The first two paragraphs aren't really relevant to the question (they look like responses to the comments on the OP), and I'm not sure about the last paragraph either. The rest of your answer is good, but it could use a couple of quotes from the books to back up your points.


Combinatorial Argument for Exponential and Logarithmic Function Being Inverse

Question: Consider the following two generating functions:
$$e^x=\sum_{n=0}^{\infty}\frac{x^n}{n!}$$
$$\log\left(\frac{1}{1-x}\right)=\sum_{n=1}^{\infty}\frac{x^n}{n}.$$
If we live in function-land, it's clear enough that there is an inverse relationship between these two things. In particular,
$$e^{\log\left(\frac{1}{1-x}\right)}=1+x+x^2+x^3+\ldots$$
If we live in generating-function-land, this identity is really not so obvious. We can figure out that the coefficient of $x^n$ in $e^{\log\left(\frac{1}{1-x}\right)}$ is given as
$$\sum_{a_1+\ldots+a_k=n}\frac{1}{a_1\cdot \cdots \cdot a_k}\cdot \frac{1}{k!}$$
where the sum runs over all ways to write $n$ as an ordered sum of positive integers. Supposedly, for each choice of $n$, this thing sums to $1$. I really don't see why. Is there a combinatorial argument that establishes this?
Comment: This seems like a nice example of the old joke that $\pi_1(\text{mathematics})$ is non-trivial. There are two different ways to prove this equality of composition of power series "from scratch" and it really seems the analytic proof is genuinely different, i.e. never uses the combinatorial identity in a hidden way.
Comment: I asked the analogous question for the composition $\log \exp x = x$ here: https://math.stackexchange.com/q/3326729/70202.
Comment: What is your question? Are you looking for a proof by the method of computing the composition of two different power series because you want to know how to prove it by that method and not just how to prove it using the fact that $e^{\log(\frac{1}{1 - x})} = \frac{1}{1 - x}$ when ever $e^{\log(\frac{1}{1 - x})}$ is defined?
Comment: @hunter: Sorry I don't understand your comment. Every proof of the fact has to pass through the identity $\exp(x) = \sum_{k=0}^∞ \frac{x^k}{k!}$. Whether or not it is a definition or a theorem, one has to prove something non-trivial, and that is where the combinatorics is hiding.
Comment: @hunter "the old joke that $\pi_1$(mathematics) is non-trivial". I like mathematical jokes ; I don't know this one. Any pointer ?
Answer: In your sum, you are distinguishing between the same collection of numbers
when it occurs in different orders. So you'll have separate summands for
$(a_1,a_2,a_3,a_4)=(3,1,2,1)$, $(2,3,1,1)$, $(1,1,3,2)$ etc.
Given a multiset of $k$ numbers adding to $n$ consisting of $t_1$ instances
of $b_1$ up to $t_j$ instances of $b_j$, that contributes
$$\frac{k!}{t_1!\cdot\cdots\cdot t_j!}$$
(a multinomial coefficient) summands to the sum, and so an overall
contribution
of
$$\frac{1}{t_1!b_1^{t_1}\cdot\cdots\cdot t_j!b_j^{t_j}}$$
to the sum. But that $1/n!$ times the number of permutations with cycle structure
$b_1^{t_1}\cdot\cdots\cdots b_j^{t_j}$. So this identity states that
the total number of permutations of $n$ objects is $n!$.
Answer: In brief, $n!$ times the summand in the sum you write down is equal to the number of permutations on $n$ symbols that decompose into the product of disjoint cycles of lengths $a_1,\dots,a_k$. More precisely, this is true if you combine all of the terms in the sum corresponding to the same multiset $\{a_1,\dots,a_k\}$.
See exercises 10.2 and 10.3 of these notes for related material.
Answer: This answer really just consists of remarks on the already given answers, to this question and the related one here:
Combinatorial proof that the exponential and logarithmic functions are inverse, the other way around
Remark 1. Let two functions $f(x)$, $g(y)$, $f(0) = 0$, $g(0) = 0$ be mutually inverse with respect to substitution, that is, $f(g(y)) = y$, $g(f(x)) = x$. The chain rule then give$$1 = (f(g(y)))' = f'(g(y))g'(y), \quad 1 = (g(f(x)))' = g'(f(x))f'(x),$$where in each case prime denotes the derivative denotes the derivative taken with respect to the corresponding argument. Conversely, if two generating functions $f$ and $g$ with vanishing constant terms satisfy these equalities, then they are mutually inverse with respect to substitution.
In particular, for the exponent and the logarithm, we expect to have two mutually inverse with respect to substitution functions, namely, $f(x) = e^x - 1$, and $g(y)= \log(1 + y)$ (the shift in both cases aims at making the free term vanishing). Note that $f'(x) = e^x$ and$$\begin{align} (\log(1 + y))' & = \left(y - {{y^2}\over2} + {{y^3}\over3} - \ldots\right)' \\ & = 1 - y + y^2 - y^3 + \ldots \\ & = {1\over{1 + y}}.\end{align}$$Now, check$$\begin{align} (\log(e^x))' & = (\log(1 + (e^x - 1)))' \\ & = {1\over{1 + (e^x - 1)}}e^x \\ & = 1,\end{align}$$as required.
Remark 2. First, if we are familiar with the combinatorial interpretation of exponential generating functions, especially composition of exponential generating functions, as explained, for example, in Chapter 5 of Richard Stanley's Enumerative Combinatorics: Volume 2 then we do not need to write out the sums over compositions: we can see directly that $\exp(\log(1/(1-x)))$ counts sets of cycles, which may be viewed as permutations, and that $\exp(\log(1-x))$ counts sets of cycles where each set of cycles is weighted by $(-1)^{\# \text{ of cycles}}$. There is a simple bijection between permutations with an even number of cycles and with an odd number of cycles: just multiply a permutation by any fixed odd permutation.
For the other way around, the theory of exponential generating functions tells us that$$\log(e^x) = \log(1+ (e^x-1))$$counts cycles of nonempty sets, where the weight of a cycle of $k$ nonempty sets is $(-1)^{k-1}$. It is easy to see how these cycles of nonempty sets correspond to our surjective functions with $f(1)=1$, but again, we do not need to write out a sum of compositions. Our bijection can be restated in terms of cycles of nonempty sets in a simple way (though describing this more formally will take longer): If $1$ is in a singleton set, push it back into the preceding set, and if $1$ is not in a singleton set, push it forward into a new singleton set.
Remark 3. Here are few other ways to look at the inverse relationship between $\log(1+x)$ and $e^x -1$.

The Möbius function of the lattice of partitions of $\{1,\ldots, n\}$ is $(n-1)!$. See http://math.mit.edu/~rstan/pubs/pubfiles/10.pdf, Example 5.5.
The duality between Stirling numbers of the first and second kinds. See https://en.wikipedia.org/wiki/Stirling_number (the section "As inverse matrices").
Brian Drake proved a theorem that explains combinatorially many pairs of inverse exponential generating functions. See An inversion theorem for labeled trees and some limits of areas under lattice paths, Example 1.4.2.


Disable or Remove APC

Question: I am too frustrated with PHP APC caching system and I wanted to remove/disable it completely from my server. I am using PHP with Nginx installed on Debian Squeeze, is there any way of doing it ?
Comment: Why are you frustrated by it?
Comment: Not an answer to your question (since the answers have been given below), but your error is pretty common. I just answered a question here which contains a fix for it: http://serverfault.com/questions/333996/unable-to-allocate-memory-for-pool-how-to-fix-it/334821#334821
Comment: Now and then I am getting **Unable to allocate memory for pool error**. I have tried many fixes given here but none of them worked for me.
Answer: Instead of removing APC, which will cause a massive performance hit, and effectively shoot yourself in the foot..
Try this:
in /etc/php5/conf.d/apc.ini:
extension=apc.so
apc.shm_size=128M
apc.shm_segments=1
apc.max_file_size=5M
apc.num_files_hint=10000
apc.slam_defense = 0
apc.write_lock=1

You can increase apc.shm_size to a value bigger than 128, say 512 if you had sufficient free RAM.
I did this on a server I run, and never ever see Unable to allocate memory for pool errors.
Comment: Yes, I'm aware it doesn't answer the question.. sorta.
Comment: It works... for the time being... :)
Answer: Either remove /opt/php5/etc/conf.d/apc.ini or comment all lines in it with a ;. Don't forget to restart your webserver afterwards.
Also check '/etc//php5/apache2/php.ini' for 'extension=apc.so' to outcomment.
If you still have the sources around, you could try to do a make uninstall afterwards. I don't know if the makefile contains this target.
Answer: If you didn't install something beside what Squeeze offers, a simple apt-get remove php-apc should do the trick.
Comment: I compiled it from the source by followin the tutorial given here

http://vladgh.com/blog/install-nginx-and-php-php-fpm-mysql-and-apc
Comment: It clearly states in that tutorial where you enabled APC. Hint: "You will have to add the extension in php.ini"
Answer: The solution is to increase memory allocated to APC.
Using a TTL of 0 means that APC will flush all the cache when it runs out of memory. The error don't appear anymore but it makes APC far less efficient. It's a no risk, no trouble, "I don't want to do my job" decision. APC is not meant to be used that way. You should choose a TTL high enough so the most accessed pages won't expire. The best is to give enough memory so APC don't need to flush cache.
Just read the manual to understand how ttl is used : http://www.php.net/manual/en/apc.configuration.php#ini.apc.ttl
You can increase memory allocated by increasing apc.shm_size.
If APC is compiled to use Shared Segment Memory you will be limited by your operating system. Type this command to see your system limit for each segment :
sysctl -a | grep -E "shmall|shmmax"
To alocate more memory you'll have to increase the number of segments with the parameter apc.shm_segments.
If APC is using mmap memory then you have no limit. The amount of memory is still defined by the same option apc.shm_size.
If there's not enough memory on the server, then use filters option to prevent less frequently accessed php files to be cached.
But never use a TTL of 0.
Use apc.php to check your config. You'll see what is really allocated and how it is used. The graphs must remain stable after hours, if they are completly changing at each refresh, then it means that your setup is wrong (APC is flushing everything). Allocate 20% than what APC really use as a security margin, and check it on a regular basis.
The default of allowing only 32MB is ridiculously low. PHP was designed when a servers were 64MB and most script were using one php file per page. Nowadays solutions like Magento require more than 10k files (~60Mb in APC). You should allow enough memory so most of php files are always cached. It's not a waste, it's more efficient to keep opcode in ram rather than having the corresponding raw php in file cache. Nowadays we can find dedicated servers with 24Gb of memory for as low as $150, so don't hesitate to allow several GB to APC. I put 2GB out of 24GB on a server hosting 5Magento stores and ~40 wordpress website, APC uses 1.2GB. Count 64MB for Magento installation, 20MB for a Wordpress with some plugins.

Disable or Remove APC


KVM gets stuck at "Booting from hard disk"

Question: I am trying to run Ubuntu-server-16.04 virtual machine on a KVM converted from .vhdx (Hyper-V) to .qcow2 (KVM).
When I import my virtual disk image and start virtual machine, the KVM hangs on "Booting from Hard Disk". I've already managed to import almost the same virtual machine, but that VM had the Grub boot loader installed, so I guess that's the problem.
I'm wondering if there is any way to import the virtual machine on the KVM that does not have the Grub boot loader?
Comment: @Stuka it' s SeaBios (version Ubuntu -1.8.2)
Comment: What about boot option, UEFI or BIOS is using?
Answer: Virtual machines created on Hyper-V these days are almost always Generation 2 virtual machines. These boot with UEFI. In order to boot the VM on a different hypervisor, you must configure it to boot with UEFI.
For instance, using virt-manager you would set UEFI (and Q35 chipset) while importing the virtual machine image.

If the UEFI option is disabled, you need to install the OVMF firmware package on your system, which provides UEFI firmware to virtual machines. The package name varies depending on Linux distribution, and you didn't say what you were running, so you will need to find this yourself.
Comment: Exactly what I needed. I didn't use Q35 however, I used 1440FX.  the ovmf firmware package was key I just `sudo apt install ovmf` for success.
Comment: @LonKaut I just saw your comment today. It's 2020 and now there is no reason to use i440fx except to run obsolete operating systems e.g. Windows 2000 and earlier. This simulates a 1996-era PC and isn't very appropriate for today's OSes, even if it does mostly work. The default is now Q35 anyway in current versions of libvirt/virt-manager.
Comment: Thank you @Michael Hampton, you are good man, you realy helped me !


Log Shipping Disk Sizes

Question: Do the drives that contain the database have to be the exact same size on the primary server as secondary?
I currently have a primary database for OLTP and a standby database used for reporting.
I'm going to create 2 new standby databases then cut over to them as an Always On Availability Group.
The 2 AG databases must be exact matches but can't the new standby disks be different size than the current primary - as long as the drive letters match and the files fit?
Thank You!
Answer: You're confusing some technologies here, unless I'm missing something or misinterpreted.  Log shipping is FAR different than Availability Groups.
Your drives on the secondary server do not have to be the exact same size, they simply need to have enough room for the DBs.  That being said, it's usually a good idea to size things the same across environments that are being replicated.  What if your primary DB grows and you have enough room on the primary but not enough on the secondary?  That will take your replication down and cause things to break.

Log Shipping Disk Sizes


Tools to use SQL Server is down

Question: I have to go to multiple locations like SQL error log file, Event Log, run sp_whoisactive whenever I am have escalations from customers that SQL Server is slow.
Is there any tool that will quickly give me a snapshot of all 3 in one(SQL Error logfile/Event(app log)/sp_whoisactive)
Comment: Why dont you invest in 3rd party tools like sentryone or redgate ? There is no out of box soution.
Answer: The BrentOzar team's new PowerBI dashboard functionality for the First Responder kit is pretty awesome.  I use it every day to monitor/diagnose issues and it's super popular as an iPad/Surface dashboard.
https://www.brentozar.com/first-aid/first-responder-kit-power-bi-dashboard/
**I should elaborate that I use their tools to gather data from many different servers into one central reporting server, and that's the one that runs the PowerBI Dashboard.  So I can monitor all of my servers at once and from the same dashboard using these features.  This means that if the offending server crashes, I can still monitor all details until (at most 15 minutes) right before it crashed.
Other than that, I've found Dell/Quest's Spotlight on SQL Server useful too.
https://www.quest.com/products/spotlight-on-sql-server-enterprise/
Comment: Thank you so much. I created a script
1. Can You Connect

Use master
SELECT * FROM sys.Databases
2. Who is active ( Adam's script)
EXEC master.dbo.sp_whoisactive
3. Find the Lead Blocker
EXEC master.dbo.leadblocker
3. What's in the SQL Server Error Log
***********************************************************/
EXEC xp_readerrorlog 0,1,NULL, NULL, NULL, NULL, N'desc'
/************************************************************/

Tools to use SQL Server is down


Design 8X1 MUX with enable using three state buffers and any logic blocks you need

Question: I have no idea where to start.
I know how to create a MUX but how can I create it using three state buffers ?
Comment: Have you looked at existing or similar designs yet?
Answer: Look at it this way. A digital signal MUX allows selection of one of several inputs gated to a single output. Such logic normally has to include an OR stage in the logic path to bring the selected input out to the output path. Now note that tri-state buffers can be used to make a wired-OR type bus (i.e. one on at a time).
Take that information and see what you can do with it to produce the MUX required by what sounds like homework.
I do not want to take away from your learning opportunity by showing a direct solution. Hopefully others here will take that same consideration!!
Comment: Considering this is quite old now, would the input to the MUX just be used to enable the tri-state buffers that would receive the inputs? That is, the only logic required would be to select one of the 8 gates with the 3 select line bits?
Comment: It is a little hard to understand your question so let me describe the logic. You use eight separate three state buffers that have all of the outputs connected together. The eight inputs of course are the MUX inputs. Next you have to design a way to select a single one of the eight tri-state buffer controls. A common way to do that is to start with a 3-bit select code on three wires and then decode the eight combinations of these wires to produce the eight individual enables for the buffers. You could build this out of a batch of 3-input AND gates and three INVERTERs or (continued)
Comment: (continued from above) use a ready made 3-8 decoder chip.
Comment: That is exactly what I was (trying) to say. thanks!


one word for "the desire to feel special to someone"

Question: Is there one word which can substitute the meaning of "The desire to feel special to someone"?
Comment: You could say you're looking for a [*cheap trick*](http://www.azlyrics.com/lyrics/cheaptrick/iwantyoutowantme.html). :)
Comment: related (same theme): [A word for the Heart-Wrenching Pain of wanting someone you can't have](http://english.stackexchange.com/questions/167528/a-word-for-the-heart-wrenching-pain-of-wanting-someone-you-cant-have)
Comment: Is there a word in your language that expresses this complex concept? This might help users give more appropriate answers. Thanks.
Comment: Good SWR question.
Comment: I think what we have here is an unresponsive *ask'n'run* user. No reply to my first comment.
Answer: Well, there's 'needy':

(Of a person) needing emotional support; insecure.

He was desperately needy in his sexual and emotional demands.

'Neediness' is fairly close to the meaning you're asking for, in that the person who is 'needy' could need another person to express their love for them. It's a pejorative term BTW.
The concept of 'codependency' might also be relevant:

People with a predisposition to be a codependent enabler often find themselves in relationships where their primary role is that of rescuer, supporter, and confidante. These helper types are often dependent on the other person's poor functioning to satisfy their own emotional needs. Codependency often involves placing a lower priority on one's own needs, while being excessively preoccupied with the needs of others.

Again, this is a pejorative term. Codependency is the desire to feel special to someone by being needed by them, though at a cost to oneself and/or to the person being 'helped'.
Trying to find less pejorative terms, a person who is sad because they are without close friends or companions might simply be 'lonely':

Sad because one has no friends or company:

Living as she is was miserable and lonely with no friends or loved ones to care about her.
The new girl's supposed to be lonely and have no friends for at least a month and a half.
She could not understand how such a great elf with so many wonderful subjects and friends could be so lonely.

The OED defines 'lonely-heart' simply as a "a sentimental name for a friendless person", but I notice that this definition hasn't been fully updated. These days, in the UK at least, 'lonely-heart' carries a very definite connotation that the person is starved of romantic company. In British English, personal advertisements are called 'lonely hearts columns'.
On the up side, being the owner of a lonely heart is better ("much better!") than being the owner of a broken heart (or so the story goes).
Comment: I have a hole in my head where *codependency* is supposed to sit. I cannot read its unhyphenated form without my brain turning it into *code-dependency*, some software architecture thing. :)  I do not expect anyone else to share my learning disability, however.
Comment: All of these words are so negative! It's not a bad thing to want to be special to someone. Everyone should have that!
Comment: Not allowed to comment, but with reference to the last part of AE's answer: *On the up side, being the owner of a lonely heart is better ("much
> better!") than being the owner of a broken heart (or so the story
> goes).* Shakespeare proposed the opposite: "Better to have loved and lost than never loved at all"
Comment: Needing emotional support and the desire for emotional support are entirely different things. Desiring some water and needing some water are very different concepts. Needy has a lot of negative connotations behind it as well.
Comment: @Gitty, yeah, I felt that too, that's why I looked around for some non-pejorative terms.
Comment: @marsh, yes. That's why I said, "it's a pejorative term".
Answer: Someone who feels insignificant or unimportant feels that they aren't special. Such a feeling is typically accompanied by the desire to be considered special by someone. These words can therefore be used to imply the feeling you seek in general. For example, "I wish I wasn't so insignificant." can be safely taken to mean "I wish someone would think I'm significant/special."
Another related possibility is the concept of validation. A person seeking validation is looking for another person to validate their existence, i.e. to confirm that their existence isn't meaningless, pointless, or inconsequential in the validation provider's opinion. Often, someone seeking validation is even looking to be praised or appreciated.


When to omit "as" in the cases below?

Question: The problem puzzling me:
1)

" I consider him a good person "

or

" I consider him as a good person"

2)

" I was appointed  commander "

or

" I was appointed as commander "
Answer: The verb pattern verb + someone + object complement is a bit confusing as to the use or drop of "as".
1 One group in this pattern are verbs such as to elect, appoint + someone + rank/title/position. These verbs are generally used without "as". Sometimes "as" or another preposition is also possible.
Examples
They appointed him captain of our team.They elected him (as) treasurer. They made him our trainer.
Verbs of this group are
to appoint, choose (as/for), crown, declare, elect (as), make, proclaim.
2 A second group of verbs uses the prep as or for:
to acknowledge as, recognize as, look upon as, regard as, speak/talk of someone as, think of as
to take someone for, mistake someone for
3
to consider is usually used without as, but it can occur occasionally: They considered her an excellent teacher.
Source: My old school grammar from the sixties by Sutton/Beilhardt, Klett Verlag.
When in doubt about the verb construction in this verb pattern I recommend
consulting Oald.
Answer: I consider him a good friend
I consider him as a good friend.
Both the sentences are grammatical, but the former is far more common and idiomatic.  The use of "as" after consider is becoming less and less common.
I was appointed (as) commander.
The use of "as' is optional; you can use or leave it, without any difference in meaning.
Answer: For 1), both are possible, but the former sounds more natural.

I consider him a good person.

For 2), appoint should be used with as, so the latter is correct, but you should add an article in front of commander.

I was appointed as a commander.

When to omit "as" in the cases below?


Synching Two ArcMap JavaScript webmaps to respond to panning

Question: I am looking for some advice on how to approach a problem I am having. I am looking to build an ArcGIS webmap using JavaScript and HTML 5 that reacts to a user panning on two separate, synchronous maps.
Modest Maps provides an excellent example of Loading Two Maps and Synching Their Panning that helps visualize what I need to do. However, I need to accomplish the Loading Two Maps and Synching Their Panning with ArcMap products.
The Overview dijit in Arcmap seems to be capturing the essence of what I am trying accomplishing. However, the overview dijit  in the widget overviewmap seems to react rather then pan synchronously.
The dijit css feeds into this map and can be used as a resource if needed. I couldn't find anything in it that would accomplish synchronous panning.
I am open to any ArcGIS suite methodology to accomplish the same as the Modest Maps look and feel.
Answer: You could try something like this:
<code>esriConfig.defaults.map.panDuration = 0;

dojo.connect(map1, "onPan", onPan);
function onPan(extent, delta) {
   map2.setExtent(extent);
}
</code>
This will add an event onPan of the first map and update the second map to the same extent.


Total unimodularity and the set of optimizers

Question: Suppose I have a totally unimodular matrix $A$ and an integral vector $b$. Consider for a vector $c$ the following linear program:
$$
\max_x c^Tx \quad s.t.\quad Ax\le b
$$
Let $S$ be the set of maximizers and let $S_{int} \subseteq S$ be the subset of integer-valued maximizers. Then is it true that $S = \mathrm{conv}(S_{int})$, i.e., $S$ is the convex hull of $S_{int}$?
Comment: I would like to say that (assuming the polyhedron defined by $Ax\leqslant b$ is bounded) an optimal solution to the LP is a convex combination of vertices at which the optimal value is attained, from which this claim follows readily. But I am not sure about this.
Comment: Thank you. In my application, $\{x: Ax \le b\}$  is unbounded but the set of optimizers are bounded.
Answer: According to the Minkowski representation theorem, every point in your feasible set is the sum of a convex combination of extreme points and a nonnegative combination of extreme directions. Every extreme point corresponds to at least one basic feasible solution (possibly more than one if the point is degenerate), and $A$ being TUM and $b$ being integer-valued means that every BFS (and so every extreme point) is integer-valued.
So it comes down to the extreme rays.

If the feasible set is bounded (no feasible rays), your answer is yes.
If it is unbounded but the objective function is strictly decreasing along every extreme ray, then your answer is yes, because the Minkowski representation of every optimal solution will necessarily have zero coefficients for every extreme ray.
If it is unbounded and the objective increases along any extreme ray, the problem is unbounded and the question is meaningless (there are no optima).
Finally, if the feasible region is unbounded, the objective function is nonincreasing along all extreme rays but constant along at least one, then the answer is no, because any optimal extreme point will anchor a ray of optimal solutions.


Is there a limit to the number of database connections from a single machine in PostgreSQL?

Question: We are planning on setting up multiple front ends behind a load balancer.
I think our database can handle the load because I'm currently measuring a database TPS of about 450  for approximately 42000 web requests (93000 transactions).
Our requirements are 278 messages/second average for the front end. I can only get around 92 non-idle queries running in the database, at a given time, and I was wondering if there's some limit to the number of connections from a single machine.
I have tried upping various connection pools and thread pools.  I was able to up the query count from 33 to 92, but I'm unable to get higher.  I am not even sure how many queries from a single machine are reasonable.  I read connections should be (2 * core_count) + effective_spindle_count.
I have been getting errors from the front end stating that it failed in getting a connection ("The connection attempt failed"), but I don't know yet if this is a failure from the front end (by hitting a limit) or the database (a configuration on the database).
I believe the max # of connections for the database is 2000 last I checked.
Is there another limit to the number of connections the database will accept from one machine?
The database is running Linux 2.6.18 on x64.
I guess I'm also wondering if the number of connections is limiting.  I don't think it is, but we did get the connection attempt failures.  The front end is running at 300% CPU (8 processors) and 25% memory. I would think we could get more bang out of both our front end and our database, but with two test servers, we normally get 250 tests/second (maxed out at 254/s for one server and 334/sec for the other ).
Comment: Never mind, it ended up being a combination of several configuration files on the front end.
Answer: You probably don't want more than 100 or so concurrent queries running on the DB. Use a connection pooler like pgbouncer if you need one and your app doesn't have one built-in.
See https://wiki.postgresql.org/wiki/Number_Of_Database_Connections
Setting a high max_connections won't make things go faster. It'll make things go slower.


Love the workplace, but don't enjoy the work I perform

Question: My previous job was a temporary position for a company that was actually closing down. Since the work was getting slower and slower, I needed to get a new job and decided I wanted to move back to my college town. I took the first (and only) job offer I received, yet looking back I could have asked more in-depth questions about the job tasks in my interview. I love the company I work for and the employees, but it's not the career field I want to be in. My current occupation is in the food manufacturing industry in quality control and assurance but my deep interests lie more in DNA, stem cells, genetic testing, and more biologically/biochemical lab based environments. I find the work I currently do to be very boring and not at all intellectually challenging. My questions are 1) when is too early to quit without looking like I can't commit to a job and 2) what advice do you have that can help me get into a field I would truly enjoy?
Comment: Have you applied for any other positions doing what you think you will enjoy?
Answer:
1) when is too early to quit without looking like I can't commit to a
  job?

For your situation I would say 1 year would be a reasonable ballpark. I am assuming you are qualified for the types of positions you mention that you would be interested in. If so, then your current job does seem like a poor fit, in which case I see no reason to wait beyond 1 year. It shows you have some patience and can commit for a reasonable duration to a position in spite of it not being in your exact field.
For perspective, I realize this varies by industry but for instance, average tenure at Google is just over 1 year. It's a different age and a different yardstick of loyalty (which reflects its flip side of job stability). So I would not worry about leaving after putting in a year.

2) what advice do you have that can help me get into a field I would
  truly enjoy?

Align your qualifications to your interests. If this alignment already exists (college degree, past experience) then your chances of getting into a field you enjoy are as good as the next person's -- at least in terms of having the basics covered. If your education/experience does not represent a natural/typical pathway into a job you are interested in, it can be more of a challenge as the onus of responsibility for proving you (and not the next guy with more fitting credentials) deserve that dream job.
Also think about how to accentuate on you resume the skills and experiences that are valued in the types of positions you are interested in. In a competitive job market, presenting your qualifications in a way that is appropriate and impressive for each specific job to which you are applying is almost as important as having these qualifications.
Finally, do your research. Explore local and regional companies (or university research centers, or government agencies) that do the types of things you want to do. Perhaps it is a medical testing lab, or a large research lab at a univesity that often posts announcements for lab technicians.
Also think of "getting the foot in the door" at the right place. What this means is applying for a job that may be tangentially/indirectly related to the type of job you actually want to do. The goal is to get into the organization. Once you are in, be patient and wait for opportunities to come up that are more closely aligned to your interests, and pursue those. Hope this helps. Good luck!


Cascading Deletes Do Not Persist to the Database in my Typed Dataset

Question: Typed datasets in ADO.Net are supposed to be able to cascade deletes and updates when a DataRelation is set up between two tables, say a parent and child.  However I have not been able to get this to work.  I should clarify: It works for me in-memory; but it does not persist into the database.
I set up a test project with two tables in my database: Colors and Boxes.  Each has an ID primary key and a name (e.g. "BoxId, BoxName").  Colors is the parent and Boxes, which also has a ColorId field marked with a Foreign Key constraint.  I then set up a Winform with two DataGridViews on it, one for each table.  I dragged the two tables into a new Dataset, and their relationship appeared in the designer.  I edited the relationship to be "Both Foreign Key and Relation," and I set all 3 referential integrity options to "Cascade" (i.e. DeleteRule, UpdateRule, AcceptRejectChanges).  I also created a DeleteCommand for the Boxes table, because for some reason the designer refused to do so.  Finally, I put a button next to each grid for saving, and put an Update() call in the event handler for each (e.g. this.boxesTableAdapter.Update(this.pOCDataSet.Boxes);)
When I run the form and SQL Profiler, I see all my data, and I can delete items in the child (Boxes) no problem.  These deletes generate a DELETE in the database, as well. Excelente.
When I do a delete in the top grid (Colors), the row I deleted disappears, and the row(s) in the Boxes grid also disappear (assuming I NOCHECK the FK constraint in the database). This looks great.  However, in the profiler, clearly only the Colors DELETE statement ran.  The Boxes row(s) are orphaned.  You don't see this on the Winform unless your restart the app, at which point the would-be deleted rows in Boxes appear with a red exclamation icon to their left, indicating they are violating the FK constraint.
This is maddening because it sure seems like my only option here is to code the referential integrity stuff myself, a la using a stored proc to perform a Colors delete (inside of which I'd also do the Boxes delete), or ordering ON DELETE CASCADE on the SQL Server, or even putting inline Boxes deletes in the Colors delete statement.  I keep coming back to the fact that the DataRelation object in my model is supposed to handle this for me.  Clearly the BindingSource objects get it, since they're removing the relevant rows from the child grid.  But why isn't the model first performing Deletes against the Boxes table and then the Colors table?
Answer: Deleting rows in a dataset will only mark them for deletion in your dataset; you still have to use a table adapter for every table in the DB you want to delete data from.  You can think of the dataset as your version of the database in memory.  Those changes need to be committed to the database in the correct order to prevent FK errors.  In your case you need to run the update statement for the parent table (colors) AFTER all the deletes for the children (boxes) have been committed like so...
this.boxesTableAdapter.Update(this.pOCDataSet.Boxes);
this.colorsTableAdapter.Update(this.pOCDataSet.Colors);

Hope this helps.


How can I handle Media sharing in my PWA app when sharing media from another app into my app?

Question: I am working on a Progressive web app that works on both web version and mobile version. I am sharing media files with others apps but when I share media from another app  (Or any other social like Facebook, Messenger, LinkedIn) into my app after selecting my app it just opens up and turns into a black screen. I need help with how I can forward the screen into my share list screen and the data which is shared by another app how can I access them. Any Help?
Answer: Double check your method is "POST" and that enctype is present.  enctype must be "multipart/form-data", and a files entry must be added in your manifest where you specify your share_target. files is an array that specifies the types of files your app accepts.
more info from: https://web.dev/web-share-target/

The foreground page cannot process this data directly. Since the page sees the data as a request, the page passes it to the service worker, where you can intercept it with a fetch event listener. From here, you can pass the data back to the foreground page using postMessage() or pass it on to the server:

    self.addEventListener('fetch', event => {
      const url = new URL(event.request.url);
      // If this is an incoming POST request for the
      // registered "action" URL, respond to it.
      if (event.request.method === 'POST' &&
          url.pathname === '/bookmark') {
        event.respondWith((async () => {
          const formData = await event.request.formData();
          const link = formData.get('link') || '';
          const responseUrl = await saveBookmark(link);
          return Response.redirect(responseUrl, 303);
        })());
      }
    });


Test a server using MTR through TCP

Question: Is it possible to use MTR over TCP? If not is there an alternative? I have done some research and I am not finding any way to do such a thing, so I'm wondering if anyone has had any experience with doing such a thing. If there really is no such thing what is the best way to do an extended test with very rapid ICMP requests to a MySQL server from a network perspective  so we can troubleshoot a very quick packet loss issue through the network.
Answer: MTR supports TCP packet traces when you are using a version that is new enough. Versions 0.85 and 0.86 (current stable builds) support this feature.
I know this is an old post, but I figured it would be relevant for someone else searching up the issue. Versions as old or older than supplied in rhel/cent 6.6 will not have this feature (Ie. Prior to 0.75).
Answer: MTR can be quite effective for this kind of trouble shooting.  Try leaving it running with an interval of 15 seconds or 60 seconds.   The statistics will give you information on which routers or segments may be causing problems.   With the recent trend to use of level 2 routers, these will be invisible to MTR (and other tools).
Many TCP stacks have counters available which can be used to identify problems.  Retransmitted and out of order packets may be indications of problems, especially if the percentage is out of normal.
If you are sending large blocks of data, then TCP windowing can cause problems.  Check to see if you may be experiencing Bufferbloat issues.
There are tools like tcptraceroute which can do similar tracing to that provided by MTR over TCP,  This can work around restrictions on ICMP echo packets.
Tools like Munin, Nagios, or Icinga can be used to monitor your network and database server on an ongoing basis.  They can also send alerts if problems are identified.
Comment: +1 for Munin, looks good.
Answer: Have you considered using nping? You should be able to generate and send packets quite rapidly. If you're trying to identify periodic packet loss or latency you could try a tool like smokeping. I've had excellent results using smokeping for trying to correlate network events over time - especially for wireless point-to-point links. There's no MySQL probe but smokeping is modular so you could write your own if you so desired.
These tools, along with Wireshark, have been very useful in eliminating Layer-3/4 issues from the equation when troubleshooting.

Test a server using MTR through TCP


Is concept brahman mentioned anywhere in Valmiki Ramayana?

Question: Is upanishadic concept Brahman (neuter gendered word ब्रह्मं meaning absolute reality/all encompassing being) mentioned anywhere in Valmiki Ramayana? I only remember reading about brahma, a grandfather of all etc (ब्रह्मः masculine gendered word)
Answer: Yes, the concept of the Brahman is mentioned in Valmiki Ramayana:

एते सेन्द्रास्त्रयो लोकाः सिद्धाश्च परमर्षयः |
अभिगम्य महात्मानमर्चन्ति पुरुषोत्तमम् || ६-११९-३१
एतत्तदुक्तमव्यक्तमक्षरं ब्रह्मनिर्मितम् |
देवानां हृदयं सौम्य गुह्यं रामः परन्तपः || ६-११९-३२
These three worlds, including Indra Siddhas and great sages pay homage
  to the great souled Rama as a Supreme person, on approaching him. O
  great one! O the destroyer of adversaries! Rama has been spoken of as
  the unmanifest and the imperishable Brahman (the absolute), established by the Vedas, the heart of Gods and the secret of all
  Gods." (from Sarga 119 of YUDDA KANDA)
भवान्नारायणो देवः श्रीमांश्चक्रायुधः प्रभुः || ६-११७-१३
एकशृङ्गो वराहस्त्वं भूतभव्यसपत्नजित् |
अक्षरं ब्रह्म सत्यं च मध्ये चान्ते च राघव || ६-११७-१४
लोकानां त्वं परो धर्मो विष्वक्सेनश्चतुर्भजः |
You are the Lord Narayana himself the glorious god, who wields the
  discus. You are the Divine Boar with a single tusk, the conqueror of
  your past and future enemies. You are Brahman, the imperishable, the
  Truth abiding in the middle as well as at the end of the universe.
  You are the supreme righteousness of people, whose powers go
  everywhere. You are the four armed. (from Sarga 117 of YUDDA KANDA)
Answer: It has been written in many parts of Valmiki Ramayan.
For example:-
एतत्तदुक्तमव्यक्तमक्षरं ब्रह्मनिर्मितम् |
देवानां हृदयं सौम्य गुह्यं रामः परन्तपः ||
Valmiki Ramayan 6.119.32
O great one! O the destroyer of adversaries! Rama has been spoken of as the unmanifest and the imperishable Brahman (the absolute), established by the Vedas, the heart of Gods and the secret of all Gods.
Now the original version of Valmiki Ramayan tends to have this shlok but it has entirely ommited from ramayan
The shlok goes as this:-
परं ब्रह्म परं तत्वं परं ज्ञानं परं तपः।
परं बीजं परं श्रेत्रं परं कारण कारणम्।।
Valmiki Ramayan quoted in ram navratn saar sangrah, Tulsi satsai tika, Manas piyush and ram paratvam
Shri Ram is parambrahman, param tatva, greatest knowledge, supreme penance, seed of all bijja (om, hreem, shreem, kleem, kreem, gan, dam etc ), greatest place and greatest reason behind all of reasons.
Hope my answer helps
Comment: Rama navaratna sarasangraha? What book is this? And as per this book, where is the verse supposed to feature in Ramayana?
Comment: This ram navratn saar sangrah shows paratvam of bhagwan shri Ramchandra using old scriptures of Valmiki Ramayan, brahma ramayan, shiva samhita etc. The verse is found in sundar kand but in present day ramayan, this verse is not available.
Comment: Amazing. Can you share a link to the book please? Any more verses from Valmiki Ramayana?
Comment: Unfortunately, this book is now extinct. There is one book that shows paratva of shri Ram but it doesn't quote Valmiki Ramayan. It quotes vedas, narad pancharatra samhitas
Comment: Oh okay. No issues.


Can a 3.3V power supply use the same type of TVS diode for the 3.3V and data lines?

Question: I have a PCB with 3.3V data lines and power supply lines.  Both require ESD TVS diodes. In the past I have used the same PESD0402-140 datasheet diode for both, but I feel like this is likely not a good idea.  The power supply can have up to 2A.  Because this diode is low capacitance and the lines are at the same voltage, is there a problem with doing this?
Comment: @Hearth Presumably the same part number and not the same individual diode.
Comment: Close/open to clear close votes after editing.
Comment: How do you intend to use the same diode for both? Wouldn't that require tying the lines together, shorting the data line to the power supply?
Comment: @DKNguyen right.  I could have been more clear on this but I meant using multiple of the same diode on the pcb.
Answer: The TVS won't fire unless its threshold is reached.
The question becomes, what kind of abnormal voltage do you expect on the 3.3V line? If it's ESD, a TVS applied to it will be dissipating the same energy as a hit on the data lines.
If there's a possibly of overvoltage from the power source, that needs a different type of protection than a TVS (or in addition to the TVS.)
Assuming overvoltage isn't a problem, then using the same TVS for data and power is fine.
Answer: In line of principle the component would be the same. However there are performance limits and parasitics to keep in mind.
Suppressors for data lines usually have less capacitive influence (often on the pF order) to avoid distortion in the signal path: an 'idle' TVS is substantially a junction capacitance plus some leakage current; all of this in the datasheet.
On supply lines you don't have this issue (often capacitance in power lines is beneficial, actually). So suppressor designed for power lines are optimized for dissipation and low leakage. The idea is that arguably on power lines transients are stronger.
You need consider the kind, shape and amplitude of the expected transient (the standard one is the 8/20µs if to want to look at how is made). Your 2A supply are not even entering your TVS… it's in shunt position, not in series like a choke. However look out for the minimum breakdown voltage since it could start conduction even at nominal voltages (look at the standoff voltage, the minimum voltage required for trigger it)
In practice since the clamp power is limited and the TVS is everything but a precision component (varistors are even worse) you'll need to derate. Your part is actually an ESD suppressor (different wave shape) but the idea is the same:

You can put on it 14V without any issue (standoff)
It triggers more or less at 250V
When it trigger you'll still have 40V to handle somehow

The 'handle' part for ESD on signal lines is usually 'let the clamp diodes eat it'. Since clamp diodes are toward the supply theorically you still would have 40V on the supply line. Luckily you should have lots of bypass capacitors and these usually suck up on line transients.
So especially for ESD unless you have special endurance requirement a data line TVS is usually applicable to a power line. For other kind of transients (like EFT, switching noise and worse of all the automotive load dump) there are tighter components available,


Magento 1.14 : Maintenance page for different stores

Question: If I have a magento install with several stores, how to configure the errors map, in order to have specific maintenance pages for each store.
The structures of the stores are app/design/frontend/theme/ and this theme has four different folders, corresponding to four different stores.
I really appreciate the help you can provide me on this.
Answer: When you create a magento.flag file, Magento send a 503 and put the website in maintenance.
In the file /errors/processor.php, you can see the function process503() which call the renderPage : '503.phtml'.
In this function, you can check the current store and call different render according to the storeId.


How to change evm token decimals?

Question: native token of my chain has 12 decimals,now i have integrated EVM functionality into my chain, is there any way by which i can change evm decimals from 18 to 12 as i don't want to change my native token decimals???
Answer: You should, and I recommend changing your native token decimals. Otherwise, you need a converter.
Then, I have a question.
Why do you need EVM? This will break almost every existing thing (such as smart contract). EVM's goal is to mock Ethereum and re-use the existing infrastructures. And the third-party developers will be so confused while developing base on your chain.

Here https://github.com/darwinia-network/darwinia-common/blob/6a9392cfb9fe2c99b1c2b47d0c36125d61991bb7/frame/dvm/ethereum/src/adapter.rs#L136.
Darwinia has been running for over 2 years.
Finally, we give up on maintaining this.
We change the decimal to 18.
So, that's my suggestion.
Comment: Answer updated.
Comment: Xavier thanks for your response , we want EVM functionality in our chain, and its been more than 1 yr our chain is live so we want to add EVM functionality. we want a solution for token decimals as our native token has 12 decimals.can you tell me something about converter.
Answer: In order to change the decimals of your native token you have to modify your chain_spec.rs file.
Import in the node/Cargo.toml sc-chain-spec
[dependencies.sc-chain-spec]
branch = 'master'
git = "https://github.com/paritytech/substrate"

And in the function development_config() or local_testnet_config() add your properties:
let mut properties = sc_chain_spec::Properties::new();
properties.insert("tokenDecimals".into(), 12.into());

And finally add in properties: of the from_genesis call:
// Properties
Some(properties),

See an example in the Parachain Template Node
Comment: alex thanks for your response but i don't need this.

How to change evm token decimals?


Is there space even though there is only color, not objects? (re-question)

Question: We can see black color when there's no light at all. What I wonder is that there is concept spacetime even though there are no objects, but only color. I mean, does black color occupy the "space" (apart from mental space and real space) when there's no light at all?
Comment: This question reflects a confused ontology.  Everything around you is made of subatomic particles, not "color."  You can't have color without the subatomic particles causing it.
Comment: No. Color needs spatial extension to be perceived, and if you want to include time, it needs a duration (like sound, our ears react to air pressure changes, our eyes react to light changes, believe it or not). When you "see black" with your eyes closed, you are seeing a surface. That is the spatial extension. When you blink, you ARE seeing a black, but for a very short time. If the duration is longer, you can actually perceive the color (personally I don't see black in darkness: I see moving purple haloes).
Comment: @RodolfoAP I think if there's no light at all, we cannot see even a surface of eyelids, and the answer should be "yes. Color needs spatial extension to be perceived."
Comment: @RodolfoAP I see that as well when staring into 'darkness'. It is either a purple or kind of blue form of a spiral spinning away as though the apex of it were being sucked into the fovea. It may be a form of synesthesia or the perception of some part of the spectrum of EM via transduction unto the fovea at the rate of picoseconds like it shows at 8:40 of this video https://youtu.be/7Ys_yKGNFRQ Is it like that for you or different?
Comment: Colours don't exist. Our eyes are funny little machines that turn electromagnetic radiation into little impulses that our brain does some processing with, and leads us to "see colour". Outside of humans, "black" or "green" doesn't exist.
Answer: I assume you are asking this question from the point of view of a strict empiricist, and that by "concept of space" you really mean to refer to a concept and not the real space of physical realist philosophy.
If so, then the concept of space can certainly exist if there is just color. In fact, 3D games on computers are an example of this. When you play a 3D game, the only thing that is really on the monitor is colors, yet you see a space inside your computer screen. That space does not really exist, but there certainly is a concept of space.
The colors on your monitor are able to simulate texture and other visual aspects that present the illusion of space, so lot of depth perception comes just from color signals. The other main component of depth perception is binocular vision, which only works close up, and binocular vision requires color signals to let both eyes pick out the same point, so arguably, the concept of space comes from nothing but color.
I say "arguably", because your senses of touch and hearing also present a concept of space to the mind, and it is controversial whether or not those concepts of space are the same as the concept of space that you get from your eyes.
Another way to interpret your question is whether you could have a concept of space if all you could see were an undifferentiated black field. I haven't seen this specifically discussed in the literature, but I'd say in that case, you aren't seeing at all. It would just be a nonlocalized sensation like fear or thirst, so, no, in that case you would not receive a concept of space from your eyes.
The distinction between perception and reality is one of the important features that distinguishes modern philosophy from its medieval predecessors. The man who introduced this distinction to modern philosophy was Descartes who discussed the problems of knowing about the real world when there are dreams and hallucinations which seem to give the same information but are false.
The empiricists who followed Descartes were very focused on this distinction, so much so that readers today who do not have the same background often misunderstand them when they use words like "experience". To the early modern empiricists, an "experience" was a purely mental event. Whether it corresponded to something in the real world was always questionable. Today, when philosophers talk about "experience", they generally seem to assume that the experience is true--that what is experienced really happened. George Berkeley was one of the early modern empiricists who did not only doubt, but positively affirmed that the real world does not exist at all; only experiences exist.
This situation of worrying about the connection of experience to reality was a major influence in philosophy until Kant, who provided an excuse to stop worrying about it. Kant's philosophy was extremely controversial, but his method at least taught everyone that it doesn't matter all that much whether experiences are true or not. We can still function in the real world and still do science, if we only assume that our experiences of nature are reliable and rule-based in just the way that nature seems to be reliable and rule-based.
In other words, it doesn't matter if your desk is noumenally real. That is, it doesn't matter if your senses are reflecting a metaphysically real desk that is substantially like what you experience or not, what matters is that your sense of the desk is what it is, and will continue to be what it is. The metaphysical reality is irrelevant to action.
In modern terms, we might compare this to a Matrix-like situation. For purposes of functioning in the Matrix, it doesn't matter whether the desk you see is really a desk or just an experience created by electrodes in your brain. What matters is that it will work just like you expect it to.
Answer: In the physical world, the absence of light is just the absence of it, not a property called blackness or darkness.
Why is this different from experience?
Putting attention on sight and "seeing" black, or any other colors, actually means putting conscious attention on the output of the visual cortex, after the sights have undergone processing (edge detection, etc). We can do this even if it is entirely dark. That's the key difference.
In pitch dark, the visual cortex will still respond with "heres what im seeing, basically black", not with nothing. Thats why we have a concept of black instead of a concept of not seeing. If it had no report at all we wouldn't experience it as black or dark; we wouldn't even experience it as "Im not seeing anything." We'd experience it as, "Im not seeing"
Comment: Yeah. There is the background radio radiation (they think from the early universe) almost everywhere. And very high energy emf waves would be light to someone who could see all wavelengths, and those penetrate through almost everything. Such a being would have to be encased in miles of led to be in the dark. Also, yes well-said your first sentence.
Comment: Indeed you cannot reify a lack of something as though it were a thing in-and-of-itself. If we had the necessary circuitry that would enable us to transduce the entirety of the EM spectrum I do not think we would see what we refer to as darkness because as you say that is merely an absence of light that is, in actuality, there; whether or not we are capable of transducing it. This makes the notion of "dark matter/energy" appear to be more of a metaphor than a physical attribute.


Rename API name of existing custom fields

Question: I am trying to rename existing field's API name. I know that before that I have to remove all references from class, VF pages..etc.
Currently I am trying to fetch all references like classes and field metadata (xml file) in VS code and trying to deploy back with the updated name but it is creating new fields instead of overwriting the existing field.
Can any one let me know that how should I proceed?
shall I have to remove all references in the org manually then change the field API name. Post that put back all changes again manually?
Answer: Assume you making the changes in sandbox and deploying to production, you will need to:
1.Comment all the references in code in sandbox and deploy it to production.
2.Rename the fields in sandbox and production manually.
3.Uncomment the code in sandbox and modify the references to the new fields API names and deploy the updated code to production.
Comment: Thanks! is there any automated way bz I have to deploy this using CICD?
Comment: There are advanced tools for deployment like clickdeploy or gearset that may make the process easier, the best tools will usually require license.  But anyway for changing API fields name you will need to follow the above steps and probably step 2 will need to be done manually, because when moving field from sandbox to production the process identify the field by its API name. If the API name was changed it cannot know that it should update something


Difference between vouch and attest

Question: Is it correct that vouch is only to claim something true without proof, while attest is to prove something true?
Comment: A question like this one should at least include a couple dictionary definitions. Why? First of all, almost anyone who answers this question would want to see a dictionary definition to get underway; to send them all scrambling when you could easily do that for them doesn't seem like good etiquette. Secondly, it demonstrates that you've done a little legwork of your own, rather than use ELL to ask a question you're only curious about but haven't tried to research yourself. You can read more guidance [here](http://meta.ell.stackexchange.com/questions/439).
Comment: then what is the difference between attest and prove?
Answer: I feel the word 'vouch' does not necessarily mean the truth 'without proof'. It can also mean providing 'supporting evidence'. For instance, if you commit that you'll get an 'A' grade in an examination and then if you get it, I say "Tim vouched his words by getting an 'A' grade." On the other hand the word 'attest' is more reliable, firmer and authentic. You 'attest' the documents and signatures. You also confirm the event using the word; for instance, "The weakness attested to his dehydration."

Difference between vouch and attest


Adding customized functions to Buildbot

Question: I have written a function in python and I would like to have Buildbot to execute this function
when it receives a "build" command. I have used the "factory.addStep()" before to add new commands through command line, but I'm not sure how I can add a python function to Buildbot. Thanks and please let me know if I'm being unclear on anything.
Answer: Do you want the code to run on the master or the slave?
If you want to run code on the master, then all you need to do is subclass BuildStep, and put your code in .start (see the link in vernomcrp's answer).
If you want to run the code on the slave, things become trickier. The simplest solution is if you can write a python script (rather than function), and execute that script. You can include the script in your repository, or download it to the slave with FileDownload or StringDownload.
If you require the code to run in the slave process it self, you need patch the slave, to add a new command, and create a corresponding BuildStep on the master, that calls your new command. This requires modifying the buildslave code on all slaves that you want to run the code on. This isn't documented anywhere, so you will need to have a look at the code to figure out how to do this.
Answer: I think we can customize buildstep to execute python function. Have a look at this link http://buildbot.net/buildbot/docs/latest/manual/customization.html. I think it has something what you want. :)

Adding customized functions to Buildbot


How's string theory phenomenology doing these days (2021)?

Question: I've seen one paper that says finding string theory vacua with particular low-energy properties is totally intractable, from a computational complexity standpoint. I've also seen people saying that they have figured out how to compactify the extra dimensions such that at low energies a SUSY standard model emerges. What's the truth about string phenomenology? Are we regularly finding new vacuua that look like our universe? Have we only ever found one? Any? How hard is it?
Comment: That sounds interesting, but why is intractable from a computational complexity standpoint? The algorithm for finding string theory vacua reduces to 3SAT?
Comment: I don't remember if this was the exact paper I saw, but here's one that contains the right information: https://arxiv.org/abs/1809.08279
Comment: Related: [What is the current status of string theory (2013)?](https://physics.stackexchange.com/q/54733/2451) and links therein.
Comment: @HankIgoe It's difficult for myself, a non-expert in complexity, to repeat statements made about it without making an error, but in broad strokes they take a look at the problem of finding stable and metastable vacuua in scalar potentials, and deduce that if you had a black box that could do it, you could use the black box to solve 3SAT. They don't do the black box argument proof themselves, instead they identify sub-problems of the vacuum problem that are already known to have such a property.
Comment: Wow, that is interesting. I didn't know they were applying complexity theory to string theory like that, or even that such a thing was possible. I don't have time to read the paper in full, and I doubt I'd understand most of it if I did, but that's good to know. Thanks for the great question.
Answer: First, the entire subject of string phenomenology is not reduced to search by brute force for some internal space that produces a low energy spectrum that reproduces the SM one. See life at the interface between string theory and particle physics for an excellent (and conceptual) string phenomenology overview.
Are we regularly finding new vacuua that look like our universe?
Yes. See A Quadrillion Standard Models from F-theory for a quadrillion of examples, an this nice blog post for divulgative information.
How hard is it? Its pretty hard. A navie argument that exhibits why is so hard to find new Calabi-Yau spaces, let alone one with semi-realistic properties, would be to recognize that that the typical number of moduli of a Calabi-Yau space is huge (sometimes of the order of hundreds), and those fields are subject to very few restrictions; then the expectation to write new CY metrics in an explicit way is hopless.
For a clear argument about the computational complexity of finding a particular compactification, with fluxes, and capable to produce a small cosmological constant in the Bousso-Polchinski scenario, see Computational complexity of the landscape.
Observation: The fact that a problem is $NP$-complete does not imply that we can not use other computational techniques, equipped with a set of reasonable assumptions, to give some special answers to this problem in a reasonable time. See Deep learning the landscape for an example of this.
Update: A nice paper on neural networks approximating Calabi-Yau metrics Neural Network Approximations for Calabi-Yau Metrics.
Comment: @Retracted I'm definitely not claiming at all that deep learning can solve arbitrary NP
-problems in reasonable (polynomial) time. What I'm showing is a concrete example in which particular deep learning architectures, equipped with a set of reasonable assumptions, are shown to be efficient in predicting the answers for a very specific NP-hard problem. Does that imply that we can use those schemes to predict geometric properties of a given CY with arbitrary precision? No. The observation is just that Deep learning does his work, well enough, to deserve the attention of the experts.
Comment: @Retracted Consider the problem of finding hamiltonian paths on a graph (an NP-hard problem). Suppose that we have discovered that a deep learning scheme (plus some assumptions and biases over the inputs) is good enough to construct hamiltonian paths in graphs of size 17x17. Does that imply that you have reduced an NP-Problem to a problem in P? No, and that's because that procedure is not general, and does not provide answers with arbitrary high precision. Something similar happens here. The procedure is not as effective as we would want and is not general; it simply gives interesting results.
Comment: Deep learning can't get around NP-completeness, it's not magic. If deep learning works, then the problem must have some "not really NP complete" character, for example it may be possible to have arbitrarily good approximations in polynomial time.


ELMAH - pass variable, and other text?

Question: I've just started playing with ELMAH.
was wondering, is there a way to pass info, eg a variable value, or some other text when an exception is thrown?.
Currently Im using this:
ErrorSignal.FromCurrentContext().Raise(e);
Answer: You can include the exception object with your custom message like this:
<code>ErrorSignal.FromCurrentContext().Raise(new Elmah.ApplicationException(Message,ex));
</code>
As seen on http://blog.omniaconnect.net/2009/07/30/using-a-static-class-for-logging-exceptions-using-elmah/
Answer: The variable depends on the context of the exception? Or is it global (Session value?)
If it's depending on context, you can just try catch and redirect an exception with a custom message manually to Elmah.
edit: snippet
... .Raise(new Exception("Your custom message with variable value"));
Answer: I throw a new exception containing the data, using the innerexception parameter to contain the original exception.
Answer: One way to do this is to extend elmah a bit so that it copies the session. The basic implementation is outlined here. This feature does not seem to be implemented in 1.2 (still beta), but I could be wrong about that.
Answer: It does suck that you are basically stuck with passing strings into elmah, but that's what exceptions are based on when you get to the meat of it (at least how most programmers deal with them).
What I do is just create custom messages that fake an object, kinda like:
Error occurred in Class.MethodName on Client Installation etc and then inject the existing exception.

ELMAH - pass variable, and other text?


Automatic data summarization with text

Question: I would like to automate periodic report writing based on data. Given one/some data tables, the machine should output texts like Stock A rose by 10% this year and hit 5 year high on 2019-12-01, or we made a large profit in sector B.
I can find the subject automatic text summarization, but seems it's about reading text and shorten it to its key sentences. Not exactly data summarization.
Could someone recommend some book/paper/video/MOOC on text generation based on data?
Answer: Then check out this tutorial generative/abstractive text summarization.

Automatic data summarization with text


Isekai manga where the main character is isekai'd by a otherworld wizard, and has superior mana

Question: I'm looking for an isekai manga where the main character is brought to another world by a wizard that gives him his "mana", but the MC's mana ends up being way stronger than the wizard's
Comment: Was this black and white? Color? Do you remember the protagonist's hair color?
Comment: Does everyone on this world have "mana", or is it special? Does he have to have "mana" added because he came from Earth, or somewhere else non-magical?
Comment: I remember that the wizard that brought him to the fantasy land have something like 1000 mana units, and the protag (who was a normal man in a normal earth) had 1.000.000 mana units, so in the end he had  1.001.000 mana. The wizard was the strongest of his land and was stunned because a normal guy from a magicless planet had much more mana than him
Answer: This is likely Ore to Kawazu-san no Isekai Hourouki, also identified here.

Tarou was just an ordinary university student until a strange old magician summoned him to another world. Upon learning that his newly acquired magical power is 8 million (8 million more powerful than an average magician), he uses his abnormally powerful magic to revive the old man that caused all this... in the form of a frog. Thus begin the strange adventures of a boy with ridiculous magical power and Kawazu, the former strongest magician, now revived as a frog.

The magician summons the protagonist and explains that an ordinary magician has a power of "1", he has a power of "1000", and grants him his power. Once in the other world, he inspects his own status and discovers that, with the magician's power, he now has a total power of 8,001,000.


What is a good click through rate (CTR)

Question: I'm new to adwords and I'm trying to figure out what a good click through rate on my ads would be.   Does anyone have any guidelines?
Answer: The numbers quoted below seem about right for campaigns which I've run (I'd add that the most abysmal CTR I've seen was 10k:1 for a banner ad on a site which ran multiple banner ads - it ran for three months, had millions of views, and resulted in three conversions, all of which canceled within their first month).

Low conversion rate 1:500.
Ordinary 1:100
Good 1:5
Unbelievable 1:1

Low CTR: 0.5%
Ordinary: 2.5%
Good: 10%
Outstanding: 60%

Source: What is the typical CTR and conversion ranges?
Answer: A bit off topic, but this is my general proceeding to improve CTRs:

Being ruthless with low CTRs below the average for a period (a month usually).
Increase the max bid on the better ones if needed.
Search for keywords similar/related to the ones with better CTRs.
Wait until the keywords reach a decent number of impressions and repeat the process.

I often have to "fight" with the customer to get rid of general keywords with poor CTRs but a high number of impressions, but eventually is usually worth it.
Answer: I realize this is an old question, and I hope I am not opening myself to ridicule via honesty but...I have a client, who was running (although mismanaged) AdWords nearly 2 years before I started with them (a year ago).
They are a smaller, local, non-glamorous business (Junk Removal in a medium city), if their search campaigns do better than 5% CTR, I am happy. Display .1% or better makes me happy...but that is also nearly double their historical average.
Like AJweb said, anything underperforming I have to fight with them to remove...they don't really grasp relevancy in spite of numerous discussions. And if (for search) I see less than 1% CTR I take a hard look at it.

What is a good click through rate (CTR)


In Spelunky HD what secret levels are there and how do I find them?

Question: In the 360 version of Spelunky (not the PC version, which is different) what secret levels are there and how do you get to them?
Answer: There are six found so far, but there may be more. I've only found the first four, so credit has to go to Todd Schlickbernd and SnapDragon for the last two.

Black Market - there's a hidden door (use bombs or the mattock) on most levels that goes here. The huge eye (from the gold key chest in the mines) helps find them.

Worm - on any level with one of those floating pink spiky things that you can jump on (mostly in the jungle levels) throw a stunned damsel so that they stick to it and then jump on yourself. After a few seconds you will both be swallowed by the worm. Strangely, you still get the kiss for doing this :-)

Haunted Castle - when you get the "Dead are Restless" message at the start of a jungle level keep an eye out for a large grave with a buried skeleton wearing a crown. Destroy the ground below the skeleton king to find a secret door. Also look out for any graves with ASH written on them - destroy the ground below for a boomstick :-D

Mothership - on the final ice level there's two exits. The one at the top goes to the mothership. You will need lots of rope or the jetpack.

City of Gold - really hard to get to this one:

You must get the eye from the mines, I don't think finding the Black Market otherwise is enough.
You must get to the Black Market and either buy the golden ankh or kill all the shopkeepers.

On one of the ice levels (3rd section) there's a giant stone head with an ankh symbol on it. You must die near this, without using bombs.
You will appear inside the stone head next to a golden pointy crown

In the temple area kill an Anubis, they will drop the Sceptre:

Finally walk over the large golden block with a hole in it - if you have everything

Hell - I haven't made it here yet, so I'm going by the guides of others:

Get to the City of Gold
Recover the Necronomicon:

This will spawn a new Anubis. This one spawns lots of red skeletons. You must kill him.
During Olmec, the final boss,move around until the book starts as it's face the most. (it starts slow ,then speeds up as you get closer). Defeat Olmec over that spot. There will be a door. This door has no step, so jetpacks or capes make no difference. You must use Olmec's face as a step as he sinks into the lava to get to hell. This is impossible without the book, as the door will not appear if you do not have it.
Comment: When trying to get to the City of Gold, dying anywhere in the Ice Caves level containing the giant stone head will revive you inside the head, regardless of how or where you died (although explosions and being crushed seems to occasionally destroy your jetpack). Also, when Olmec falls into the lava below the entrance to Hell, do note that he continues to sink and you have a window of 1-2 seconds to enter the door. While waiting to get in, Magma Men can jump out of the lava and push you in, so careful!!
Answer: Real last step:
During Olmec, the final boss,move around until the book writhes at it's face the most. (it starts slow ,then speeds up as you get closer). Defeat Olmec over that spot. There will be a door. This door has no step, so jetpacks or capes make no difference. You must use Olmec's face as a step as he sinks into the lava to get to hell. This is impossible without the book, as the door will not appear if you do not have it.
The worm is much larger than a standard level. In a pool of acid inside is the Crysknife. It one-hit-kills ANYTHING. Be sure to retrieve it. Also, in the green background decoration with a silhouette, whip it to free a secret character.
At the top inside of the haunted castle is a secret character. Whip the coffin to free him.
The mothership is reverse and drops you off at 3-3, although it appears at 3-4. Within are alien lords and the alien queen, whom guards a very destructive plasma cannon.Break open the distinct alien pod in the background to unlock a secret character.
The black market entrance does NOT appear on most levels.Only one chance to enter appears on 2-1, 2-2, or 2-3.


Multiway switching with SPST switches

Question: Is multiway switching at two locations with SPST switches possible? Normally SPDT switches are used for this, right?
Answer: No it isn't. A simple multiway system such as both ends of a corridor relies on normally closed and normally open switches operating in tandem at each end. I hope I'm wrong because it's more important to learn than be correct.
If of course you use an SPST  to control a changeover relay contact then I'm presuming that would be cheating!
Comment: Normally open or normally closed has (to my mind) nothing to do with SPDT switches, because one throw is closed while the other is open at all times, making the label "normally" ambiguous. Also "in tandem" implies that the switches somehow operate simultaneously, but they are completely independent.
Comment: @JYelton A normally open and normally closed switch (in tandem) can form an SPDT switch as shown in your drawing i.e. NO and NC with a common connection to each = SPDT.
Answer: Yes! It can be done with four sPsT switches:

Switches need to be connected from the opposite poles and each pair needs to be actuated simultaneously.
Comment: This should be the accepted answer.  Very creative!
Answer: As phrased, your question doesn't specify how the switches are expected to operate.
I'll assume you are referencing a three-way switch arrangement, commonly used in residential wiring to control a light from two distinct locations. In this scheme, the switches are SPDT and are arranged such that the light may be turned on or off from either location:

(From ezdiyelectricity.com)
Either switch can be used to change the light state.
If both switches are SPST, then the following options exist:

both switches closed to enable the light; one open to disable
one switch closed to enable the light; both open to disable

To demonstrate this:

simulate this circuit – Schematic created using CircuitLab
The use of SPST switches to control a single load is typically used when safety or security is a factor, rather than convenience.
In example 1, this arrangement is used to allow multiple emergency stop buttons to disable a machine. Example 2 would be less for safety and more for convenience, but is rarely used because all switches must be open to disable the device. It would be more useful using momentary switches, for example, where it might be used to allow the starting of equipment from various convenient locations.
You wouldn't want to do this for a light in a hallway because you would sometimes have to travel to both switches to get the desired result.
Answer: No, multiway switching requires two SPDT switches. Multiway wiring methods like staircase wiring, carter wiring, coast 3-way wiring, etc are by using two SPDT switches.

Multiway switching with SPST switches