Android AccountManager security

Question: I've asked this question before, but got no suitable replies, so here I go again. How does the Android AccountManager which is used to store your Google, Facebook, Twitter, etc... usernames and passwords implement security. For instance, off my phone is rooted, can't a third party app read the account passwords of wherever it stood them. I figure that the account manager must store these passwords somewhere on the device our logging in would not work, especially if the device was offline. Thank you for your explanations.
Comment: We cannot look into the sources, but it doesn't necessarily store passwords. A token obtained from the server might be sufficient (and is what's normally used – hence when unautorizing a device, you don't need to change your password as it simply invalidates the token assigned).
Comment: See my answer below (time for comment-cleanup). I don't think it's using OpenID, but I cannot tell for sure.
Comment: Interesting, I think I understand now. Perhaps you can make that an answer. But why are the sources not available? I thought Android was open source. Thanks.
Comment: Izzy, des the system you describe use OpenID? Thanks.
Comment: So, if I'm offline, account manager will be useless to offline apps?
Answer: We cannot look into the sources of the Google AccountManager: while Android itself is open source, the Google apps are not. But we can make an educated guess:
It's not necessary to store passwords on the device in this case. You once enter your password, it gets confirmed server-side, and you receive an "authentication token" in return. That token is saved on the device, and used by it until it gets invalid (either by expiring or by being revoked) – in which case you will be asked again for your password, and the game starts over. This is why you can simply "revoke access" from devices without having to change your account password.
The token is always specific to the device (same reason – otherwise you couldn't revoke access from one device without affecting any other). I can't say whether the token would be useless to some "root app" aquiring it without your permission (non-root apps would have to ask you for your confirmation when first accessing it), or what they could do with such a token while offline (again, closed-source parts) – maybe someone else is able to shed a light on that.
Comment: Thank you for your answer. I am really hoping that someone else will be willing to provide some more detail this time around. Interesting to know that the Google apps are not open sourced.

Android AccountManager security


Infinite distinct factorizations into irreducibles for an element

Question: Consider the factorization into irreducibles of $6$ in $\mathbb{Z}[\sqrt{-5}]$. We have $6=2 \times 3$ and  $6=(1+\sqrt{-5}) \times (1-\sqrt{-5})$, i.e. $2$ distinct factorizations. And,
 $$6^2=3 \times 3\times2\times2$$
$$=(1+\sqrt{-5}) \times (1-\sqrt{-5}) \times (1+\sqrt{-5}) \times (1-\sqrt{-5})$$
$$=(1+\sqrt{-5}) \times (1-\sqrt{-5})\times3\times2.$$
More generally, $6^n$ will have $n+1$ distinct factorizations into irreducibles in $\mathbb{Z}[\sqrt{-5}]$ by a simple combinatorial argument. But, can we construct a ring in which there exists an element that has an infinite number of distinct factorizations into irreducibles? To make life harder, can we construct an extension of $\mathbb{Z}$ in which this happens? I have been thinking about this for a while and have managed to find no foothold.. Any help is appreciated.
Answer: Hint $\:$ Let $\rm R = \mathbb R + x\:\mathbb C[x],\:$ i.e. the ring  of all polynomials with complex coefficients and real constant coefficient. Here $\rm\:x^2\:$ has infinitely many distinct factorizations into irreducibles
$$\rm x^2\ =\ (c\: x)\: (c^{-1}\: x),\quad c = r + {\it i},\quad \forall\: r\in \mathbb R$$
The factors are nonassociate irreducibles in $\rm R$ since, for $\rm\:r,s\in \mathbb R$
$$\rm (r+{\it i})x\ |\ (s+{\it i})x\ \ in\ \ R\iff \frac{(s+{\it i})\:x}{(r+{\it i})\:x}\in R\iff \frac{s+{\it i}}{r+{\it i}}\in \mathbb R\iff r = s$$
Note $\:$ Such constructions are often used by ring theorists since they yield a very rich source of (counter-) examples, e.g. see   $\ $ M. Zafrullah, Various facets of rings between $\rm\:D[X]\:$ and $\rm\:K[X].$
Comment: Very nice! Thank you!
Answer: Let $\mathbb{A}$ be an abbreviation for $\mathbb{Z}[\sqrt{-5}]$. Let $I$ be an infinite index set, in our case specifically the non-zero integers, and let $D$ be a non-principal ultrafilter on $I$.
Consider the ultrapower $\mathbb{A}^I/D$. Briefly, the elements of $\mathbb{A}^I/D$
are the equivalence classes of functions $f: I\to \mathbb{A}$, where we say that two functions $f$ and $g$ are equivalent modulo $D$ if $\{i:f(i)=g(i)\}\in D$.  Addition and multiplication are defined coordinatewise modulo $D$.
The structure $\mathbb{A}^I/D$ has the very nice feature that every first order sentence in the language of rings which is true in $\mathbb{A}$ is true in $\mathbb{A}^I/D$.
Let $f: I\to \mathbb{A}$ be defined by $f(i)=6^i$.  Then $f/D$ has infinitely many factorizations as a product of irreducibles.
Another way: Or else one can use the Compactness Theorem. Let $\mathcal{L}$ be the language of ring theory, augmented by a constant symbol for every element of $\mathbb{A}$, and an additional constant symbol $c$. Let $T$ be the theory whose axioms are all sentences of $\mathcal{L}$ that are true in $\mathbb{A}$.
Form the theory $T'$ by adding to $T$ the infinitely many axioms $\varphi_n(c)$, where $\varphi_n(c)$ "says" that $c$ is a product of $n$ irreducibles in at least $n$ "really distinct" ways. For any $n$, one can produce a sentence $\varphi_n(c)$ of $\mathcal{L}$ that does the job.
Note that for any finite subset $F$ of $T'$, there is an interpretation of $c$ in $\mathbb{A}$ such that with that interpretation, the structure $\mathbb{A}$ is a model of $F$.  So by the Compactness Theorem, the theory $T'$ has a model $\mathbb{A}^\ast$.  The interpretation $c^\ast$ of $c$ in $\mathbb{A}^\ast$ satisfies all of the $\varphi_n$, so $c^\ast$ can be expressed as a product of irreducibles in infinitely many ways.
The ultrapower construction of the first solution can be thought of as a sort of explicit way to construct a structure with the properties of $\mathbb{A}^\ast$.
Comment: Thank you, but I do not know what filters are, but I am reading about them as I type and hopefully will understand your answer soon.
Comment: Informally, think of an ultrafilter on $I$ as a kind of **measure**.  The "measure" only takes on values $0$ and $1$, is only *finitely additive*, but is defined for *all* subsets of $I$.  With the understanding that we only have finite additivity, you can think of $\{i:f(i)=g(i)\}\in D$ as meaning that $f=g$ "almost everywhere." There are more familiar examples of what you want. But, at least for people with some background in model theory, the example I gave is absolutely *automatic*, no thinking required.
Answer: Let $X_1,Y_1,X_2,Y_2,\dots$ be indeterminates, and put
$$
A:=\mathbb Q[X_1,Y_1,X_2,Y_2,\dots]/I,
$$
where $I$ is the ideal generated by the elements $X_nY_n-X_1Y_1$ for $n=2,3,\dots$, and define the elements $x_1,y_1,x_2,y_2,\dots$ of $A$ as being the respective canonical images of $X_1,Y_1,X_2,Y_2,\dots$.
Then the $x_n$ and $y_n$ are irreducible and non-associate, and $x_1y_1$ is equal to $x_ny_n$ for all $n$.
EDIT. The simplest way to prove rigorously the above assertions is perhaps to use Bergman's Diamond Lemma.
A statement of the Lemma is given on this n-Lab page.
The precise reference is:
The Diamond Lemma for Ring Theory, Advances in Mathematics, Volume 29, Issue 2, February 1978, Pages 178-218, George M Bergman.
Here is a non-free access to the article. (It belongs to Elsevier...).
I'm sure some proofs of the Diamond Lemma are available on the web, but I haven't been able to find any. If you know one, please tell me, or edit this answer. Thanks in advance.
Comment: Dear @Fortuon: I took your comment into account in my edit. Please let me know if this is still unclear.
Comment: Could you please elaborate on "the obvious way" for an inexperienced fellow?
Answer: If you are only interested in behaviour in the ring of integers of a number field (such as $\mathbb{Z}[\sqrt{-5}]$) then you will never get infinitely many different factorisations of an element.
These different factorisations come from reordering the (finitely many) prime ideals in the unique factorisation of the ideal generated by your element.
Answer: Here's a construction similar to the one used by Math Gems, in the first
answer. Let $\mathbb Q$, $\mathbb R$ be the fields of rational and real numbers respectively and let $X$ be an indeterminate over $\mathbb R$. Consider the ring $S=\mathbb Q+X\mathbb R[X]=\{f\in \mathbb R[X]:f(0)\in \mathbb Q\}$. That such a monstrosity is an integral domain, can be easily checked, say from the reference given by Math Gems. Note that a typical element $f$ of $S$ can be written as $f=q_{0}+\sum_{i=1}^{n}r_{i}X^{i}$ where $q_{0}\in \mathbb Q$ and $r_{i}\in \mathbb R.$ So
coefficients of $X$ are real numbers. (Any (nonzero) real number can be a
coefficient of $X$!)
Notice that as $S$ is a subring of $\mathbb R[X]$ every unit of $S$ is a unit of $\mathbb
R[X]$. So $u\in S$ is a unit if and only if $u$ is of degree zero if and
only if $u\in \mathbb Q.$ Thus $f\in S$ is a nonunit if and only if $\deg (f)>0.$
Now this can be used to establish the following
Observation A: $S$ satisfies ACC on principal ideals and so is atomic, i.e.
every nonzero nonunit is expressible as a product of at most a finite number
of irreducible elements.
Illustration: Let $f,g\in S$ such that $fS\subsetneq gS.$ Then $f=gh$ where $%
h$ is not a unit and so is of positive degree. But then in $S,$ $g$ properly
divides $f$ implies that $\deg (g)<\deg (f).$ Now as $\deg (f)$ is finite
for each $f\in S$ and so $fS\subsetneq f_{1}S\subsetneq \dots\subsetneq f_{n}S$
... must stop after a number of steps.
Having established that $S$ is an atomic domain we now proceed to show that
Observation B: $S$ is not a UFD.
Illustration: Note that $X$ is an irreducible element or atom, being of
degree $1$, but then so are$\frac{1}{\sqrt{2}}X,$ $\sqrt{2}X$ and all  $X,$
$\frac{1}{\sqrt{2}}X,$ $\sqrt{2}X$ belong to $S.$ Note that $X$ and $\frac{1}{%
\sqrt{2}}X$ are not associates, since $X/\frac{1}{\sqrt{2}}X=\sqrt{2}$ which
is not in $S$ and $\frac{1}{\sqrt{2}}X/X=\frac{1}{\sqrt{2}}$ which again is
not in $S.$ In a similar fashion we show that $X$ and $\sqrt{2X}$ are not
associates.
Now note that $X^{2}=(\sqrt{2}X)(\frac{1}{\sqrt{2}}X).$ So $X\mid (\sqrt{2}%
X)(\frac{1}{\sqrt{2}}X)$ yet $X$ does not divide either of $(\sqrt{2}X),(%
\frac{1}{\sqrt{2}}X).$ Now recall the definition of a prime element it is a
nonzero nonunit $p$ such that $p\mid ab$ implies that $p\mid a$ \ or $p\mid
b.$ So, in $S,$ $X$ is not a prime. Now one of the criteria for a domain to
be a UFD is: $D$ is a UFD if and only if every nonzero nonunit of $D$ is
expressible as a product of at most a finite number of irreducible elements
and every irreducible element is a prime. As we have shown that the
irreducible element $X$ in $S$ is not a prime we have essentially
established that $S$ is not a UFD.
Observation C: In $S$, the element $X^{2}$ can be expressed in an infinite
number of ways as a product of two irreducible elements which are not
associates of $X.$
Illustration: (i) Our first choice is noting the following. There are
infinitely many distinct positive primes $p$ in $\mathbb Z,$ the ring of integers,
and for each $p$ $\sqrt{p}$ is irrational and so $X^{2}=(\sqrt{p}X)(\frac{1}{%
\sqrt{p}}X).$ Works fine using the same argument as we used in case of  $%
X^{2}=(\sqrt{2}X)(\frac{1}{\sqrt{2}}X).$
(ii) There is one snag with the factorization in (i) and that is,  we have
not been able to express $X^{2}$ as product of two non-associated atoms in
infinitely many ways. For, it so happens that $(\sqrt{p}X)$ and $(\frac{1}{%
\sqrt{p}}X)$ are associates as $(\sqrt{p}X=p(\frac{1}{\sqrt{p}}X)$ . \ The
problem arises from the fact that $(\sqrt{p})^{2}p$ a rational number. That
can be solved by selecting a set of distinct irrational numbers $\{\alpha
_{i}\}$ such that  that for each $i$ $\alpha _{i}^{2}$ is irrational, taking
$\alpha _{i}=$ $\sqrt[3]{p}$ for instance where $p$ ranges over distinct
positive primes of $Z.$ In this case $X^{2}=$ $(\alpha _{i}X)(\frac{1}{%
\alpha _{i}}X)$ where  $(\alpha _{i}X)$ and $(\frac{1}{\alpha _{i}}X)$ are
irreducible elements that are not associated to each other and of course
neither of $(\alpha _{i}X)$ and $(\frac{1}{\alpha _{i}}X)$ is an associate
to $X.$
Observation C, hopefully, does answer the question. I have taken the longer
route to include the usual concepts. Now here's something that I would like
folks to think about:
Question: How can we express $X^{3}$as a product of three irreducible
elements, in $S,$ as $X^{3}=(\alpha _{1}X)(\alpha _{2}X)(\alpha _{3}X)$ in
infinitely many ways, where $X$ is not an associate of any of $\alpha _{i}X.$ One
answer is simple. Note that $pX^{3}=(\sqrt[3]{p}X)^{3}$ for any positive
prime, but the answer will be more interesting if $(\alpha _{1}X),(\alpha
_{2}X),(\alpha _{3}X)$ are mutually non associated.
OK guys I have probably overused your hospitality and probably made some mistakes too. So feel free to point out if you find any.
Comment: Guys, I was hoping that someone would edit it. I used a Tex software which does not agree with the TEX you guys use. So there is one formula that stayed as it was and it looks terrible. Oh and if my "bad reputation" has reached here too then let me know I would move my stuff elsewhere. You can reach me at firstname.lastname@example.com
Comment: I forgot to mention that some material included here was published in http://www.lohar.com/researchpdf/examples_in_modern_algebra_with_which_students_can_play.pdf


Is there teleology in (modern) science?

Question: Teleology (the research of a phenomenon according to its "finality", its end-goal) is a subject that's often controversial (at least to my knowledge), and I'm not sure I've seen it in science (more specifically, natural science). Is there any teleological theories in (natural) science (more particularly, modern science)? If not, is there a fundamental rejection of teleological research?
Comment: The [SEPh article](https://plato.stanford.edu/entries/teleology-biology/#natsel) is old and needs to be rewritten.  But anyway there's a substantial literature on evolutionary accounts of teleological notions in biology, such as "the function of the heart is to pump blood."  [This paper by Godfrey-Smith](https://drive.google.com/open?id=0B6oYmzobonqobGxmaDlSN3lpTGc) is a classic statement of one major position in that literature.
Comment: This is what I got from Wikipedia: "In modern science, explanations that rely on teleology are often, but not always, avoided, either because they are unnecessary or because whether they are true or false is thought to be beyond the ability of human perception and understanding to judge. But using teleology as an explanatory style, in particular within evolutionary biology, is still controversial."
Comment: There was an essay by Stephen Gay Gould on the Gaia Hypothesis that struck me as being teleological.
Answer: A telos in natural science could be taken as the evolution of an evermore refined being.  However, with changes in environment the specific required characteristics may turn out different.  So 'refined' in various circumstances may mean most efficient, skilled or resilient etc.  Broadly, it could come down to saying the end of being is surviving, or being.
Applied to nature in general, the end of nature is 'to nature', that is to carry on doing what nature does.
So perhaps it becomes meaningless by way of being blindingly obvious.
I will throw in a quote from Derrida's The Ends of Man, page 13.

In the thinking and the language of Being, the end of man has been
  prescribed since always, and this prescription has never done anything
  but modulate the equivocality of the end, in the play of telos and
  death.  In the reading of this play, one may take the following
  sequence in all its senses: the end of man is the thinking of Being,
  man is the end of the thinking of Being, the end of man is the end of
  the thinking of Being.  Man, since always, is his proper end, that is,
  the end of his proper.  Being, since always, is its proper end, that
  is, the end of its proper.
Comment: But would a scientist research something *by its telos*? As in, would it be acceptable to define a research by looking at the subject's end-goal?
Answer: Yes. There appears to be a consensus around teleology being present in the understanding of black holes. Checking for "teleology" in the arxiv might be illuminating and also remembering that until recently the least action principle used to bee seen as a kind of teleology.
A popular essay  by Matt Visser asserts:

Teleology in physics has a very mixed score-card — the only known
  mainstream physics example is black hole event horizons...Black hole
  event horizons in general relativity are teleological; one has to wait
  till the trump of doom, and then back-track from the infinite future,
  to know whether or not anevent horizon is present right now.

(Matt Visser * From mindless mathematics to thinking meat?*)
The view is not uncommon as two other physicists point

Access to the complete space-time manifold is required to describe the
  black-hole. This feature necessitates that black-hole dynamics is
  specified by future or teleological boundary condition. Here we
  demonstrate that the statistical mechanical description of
  black-holes, the raison d'etre behind the existence of black-hole
  thermodynamics, requires teleological boundary condition.

(S. Bhattacharya, S. Shankaranarayanan, 2017, Black-hole event horizons-Teleology and Predictivity)
Vladislav Terekhovich (2015) discusses The Metaphysics of the Principle of Least Action
and there are earlier treatments e.g. Stöltzner, M. (1994).
Action principles  and  teleology,   in Inside  Versus  Outside
 Berlin Heidelberg: Springer, p.33-62.

Is there teleology in (modern) science?


How tight should studs be when framing in place

Question: How tight should studs be when framing a wall and cutting them to length and installing them in-place?  Ideally I'd be able to cut my wood accurate to 1/64th, but that ain't happening.  If they are a little short than the stud will just wobble, but if they are long then they need a little nudge with the hammer.  The friction seems to be the way to go, but are there problems if the stud is TOO long? (i.e. can the floor move up, thereby pushing on the studs -> joists?  FWIW, I'm on the East Coast and not somewhere crazy like CO where they have to have floating walls.
Answer: I assume that you're referring to interior, non-bearing walls, such as those in a previously unfinished basement. Ideally the studs will fit just snugly enough to hold them in place as you nail them in. You're right that you can jack up the floor if you force them in, but it's more likely that they'll bow a bit.
If they're slightly short it will be more challenging to nail them in accurately, but it won't likely cause any issues. Most of their function is to support drywall, and they'll do that just fine.  You can always pop a shim in at each joint, or squirt a dab of construction adhesive to fill the gap.
Answer: You have 2 different scopes. One is structural the other cosmetic. If the studs are too short, the nails are being asked to carry more than they should. It will eventually compress. If they are too long, you will distort the floors and walls leading to unsightly finished details.


Is there a more concise way to say "cars stuck in traffic"?

Question: I am searching a word for describing cars stuck in traffic.  When I googled the phrase "stuck cars", I found out that stuck cars imply cars stuck in ditches rather than traffic.
Comment: @rama9, I don't think there's an adjective for that in English.
Comment: My question has been edited.  I would like to know a modifier (adjective) that modifies the noun "cars", such as "stuck cars", or "congested cars"
Comment: Cars also get stuck in snow, probably more often than ditches.
Comment: Yeah, snow or mud.
Answer: I don't know what exactly you mean by an abbreviation, but in English, a situation when there are just too many cars on the road where little to no movement is possible is traditionally called a traffic jam or a traffic congestion. To find out more about what other expressions related to cars stuck in traffic exist in English, follow the link to the Wikipedia article on traffic congestion that I provided.
Example:

The reason I'm so late today is because my car got caught in a huge traffic jam this morning.
Comment: It's probably more likely that you would say "...because I got caught in a huge traffic jam..."  Saying your car was caught sounds a bit odd, although it's perfectly fine.
Comment: Thank you for you comment. I was trying to think of an illustrative, yet simple, example that involved a car. I think that's why I ended up with *my car* there instead of *I*.
Answer: I would use bumper-to-bumper traffic.

Due to a truck collision, cars on the freeway were stuck in bumper-to-bumper traffic.
Answer: You could say, "Heavy Traffic", "Congestion", "Clogged Roads", "Heavy Delays", or, even depending on the cause, you could say, "Gaper's Delay" or "Rubbernecking" if the cause is because people are staring at an accident. You could also say, "Traffic was at a standstill", or call the highway "A parking lot".
Answer: You can use gridlock or deadlock. It is defined by Oxford Dictionaries as follows:

A situation of very severe traffic congestion.
'the city reaches gridlock during peak hours'


How should I plan a backpacking trip with people who have never backpacked before?

Question: I want to go backpacking with a couple friends, but I'm the only one of us with any experience, and I mostly day hike. I've only done a couple of backpacking trips. They've never backpacked, and only hiked occasionally.
Comment: One question no one else asked: how enthusiastic are the new people?
Comment: @whatsisname, They're quite enthusiastic.
Comment: In addition to the good answers below, have them pack ahead of time following your list, and do at least 1 or 2 day-hikes with full packs and cook outside. If you have a local park with terrain similar to where your overnighter will be, that's a good test.
Answer: Make the trip short and easy. Better to have them wishing for something longer than regretting that they're stuck on the trail. Just spend one night on the trail, in good weather if you can arrange it. The four most important things for comfort are sufficient water, good shoes, a comfortable pack, and a warm, dry place to sleep. On a short trip, you don't even need much food.
Make a suggested gear list for the new people. Make it fairly detailed (x pounds/calories of food, x liters of water, waterproof tent (Test it!), a well fitted pack (Try it first!) specifics items of clothing).
Tell them to practice walking around with the weighted pack beforehand, in whatever shoes they want to wear. If possible, go on day hikes with them carrying a weighted pack to ensure that they do this.
Newbies make mistakes, and a one night trip minimizes the consequences. Plan to cover less distance than you think you should. Five miles is plenty for day 1, or just 2-3 miles if it's steep. It'll let you get a late start and still be feeling good when you make camp. The second day can be longer because you'll end up at home in your own bed, but still keep it to under 10 miles if it's flat, or under 5 if it's steep. You're with people who aren't used to hiking with weight. It's very different than walking around carrying nothing.
This answer is based on my experience not following these guidelines. I went on a 3 day hike with two people who regularly run marathons, but had never been on more than short day hikes. They're used to suffering for the sake of fun, so it worked out, but they had a lot of trouble despite a high level of fitness.  One of them had borrowed a pack the day before from someone who was 8 inches taller, their tent leaked badly, they carried about a week's worth of food and lots of unused gear, and we ran short of water (I carry a filter, but it was a dry summer. It took a while to find a stream that hadn't dried up). At least their shoes fit. But running 26 miles non-stop in under 4 hours turned out to be poor preparation for hiking 8 miles carrying 40 pounds on your back. And if a newbie hasn't tried hiking with 40 pounds, they won't realize why they should try cutting that down to 20-30 until it's too late.
Comment: I would also choose a well-traveled hike area with access by rangers. Just. In. Case. I had an experience a couple of years ago in an area I had backpack several times with a newbie. Unfortunately, with the drought here in California, the usually plentiful water spots were dry and it was unseasonably hot that day so we ran out of water much before we would arrive at the certain water source. Because we were on a well-travelled trail (Yosemite) we were able to "borrow" enough water to get us to a source from other hikers we came across.
Comment: +1 I'm surprised no one else mentioned testing the tent! It's a lot less stressful to figure out tent poles for the first time in your backyard, rather than at the end of a day of hiking while the sun is on its way down.
Answer: As mentioned in other answers, starting with a short hike is good.  A week-long monstrosity through rugged terrain, while possessing a high "cool factor," isn't ideal for getting new backpackers hooked.  Rather, I'd aim for a short one-or-two night hike where bailing out midway through is still an option.  When I was a kid, I remember my first overnight hike was still within a three or four hour hike to the car.  That way, if something went really wrong for someone in the group, getting back to the car and civilization was still possible.
With regards to gear selection and packing, providing them with some guidelines (and "must have"s) is a great idea.  In one organization I was in, the standard procedure for everyone's first overnight hike was to bring your (completely packed) backpack to the meeting before the hike, unpack to show what was in it, then repack.  This probably is more reasonable for kids than for adults, but offering to look over what they've packed might be appreciated.
The last thing I'll mention is that you might need to bring slightly more stuff just in case they forget something.  When I'm driving people to a trailhead, I'll put some extra water bottles/food/first aid materials in the car in case they forgot to bring enough (underestimating water needs is probably the most common error I've seen).  Obviously you can't carry enough water/food/gear for two people, but having extra in the car and asking if they need some before departure can save worlds of pain.
Comment: +1 for having extra in the car, it doesn't hurt, and it's really appreciated. I would also encourage to have extra in the car *for after the hike*. It's always nice to clean-up (quickly), and change clothes/shoes *before* climbing in the car, promotes a much better smell during the trip back home too.
Answer: Oversee their packing or even pack for them. Chances are if they rarely hike they have little if any backpacking gear. Be sure they do get whatever they need. I would take them on a shopping trip (to my garage) and help them pick and adjust the various equipment I would recommend they take. Make sure the packs and shoes feel comfortable.
Go well under your limit for both distance and weight. Pushing yourself is almost certain to be beyond their comfort zone. Plan extra rests and view points if possible and probably avoid steep climbs.
Carry extra first aid supplies especially foot related supplies. Minor injury or irritation is pretty common when doing something you aren't used to. It may be a good idea to take a shoes off break at some point early on to be sure they aren't trying to hide problems, people can get their pride set in unhelpful ways and may have ideas about "toughing it out" that are best avoided.
Plan entertainment of some kind for the evening. A fire, some stories, a lesson in knots or field craft, maybe a game. It doesn't have to be much, but if you do anything to set the experience apart from hanging out on a couch it will make it special.
Consider de-fussification. Bring a secret treat, comfort item or present for each person to be used incase of panic. Chocolate generally goes over well. Unexpected pillows can really change a new backpacker's out look.
A couple points about leading a trip that seem to have been missed: Tell someone where you are going and how long you expect to be out. And make sure you know what rules apply to the places you will hike, camp and park.
Answer: I can only tell you what I do, when I am in this situation. It's tricky, and getting everyone to agree can be tough, but it works.
Take charge
First, be the leader. Don't just suggest people bring x or y, make them. Assert control over the trip and make sure to keep it. Now that doesn't mean you have to be an ass hat, but you do need to "take charge".  Make sure you it's clear that you're going and they are coming along. It's hard to describe, because I don't mean to suggest that you be overbearing. But for example, make sure that everyone checks their gear with you. Make sure that everyone checks their food with you.
When people want to split off from the group make sure they know to check with you. Make sure they have you check their tent (or whatever) before they sleep in it.
I know this seems silly, but your the one with experience. Be ready to suggest products and items that they will need to bring or buy. Be prepared to call the trip off if it's not going "your way" on a critical issue. Again, sounds bad. But if you say to bring drinking water, and someone is insisting they don't need to because you can just drink from the river, then you suggest that they get some kind of water purification system and they go "no, river water should be fine", you need to make the call and stop the trip.
Where to go
Next, choose a short trip. If it's their first time, then they may not be prepared for what hiking means. Specially if it's off trail. A 2-mile run on a track is a lot different then a 2-mile walk on a animal trail. I would suggest a 1 mile in, setup camp, 1 mile or less out arrangement. Yes, that means a lot of time at camp, but you don't want to be setting up a tent for the first time at dusk. And you really don't want to have to deal with muscle pain, back pain, sore feet, etc. on the way out. You want to leave them wanting more.
Before the trip
Third, have a planning day. Get everyone together for dinner or something and go over what the requirements are. Focus on shoes, packs, survival gear and food.  Then, on the second half of planning day head to the stores. Get everything you don't have. Be ready to answer questions about weight, what is needed and what is nice to have. I usually have to remind people that why they want to take is what they will have to carry. That usually gets them to put down the big hibachi grill and choose something more reasonable.
Then head to the grocery store. Get the food you want to take. Of course focus on lightweight high-energy foods. Be ready to explain your choices. Keep it simple. Canned food, beef maybe, fruits, nuts, and grains. Even though you may be comfortable preparing a lavish meal over a camp fire, it takes practice that they don't have. So stick with foods that are easy to cook, or don't require cooking. Remember to keep weight in mind. 10 pounds of steak sounds good, but remind them they they will have to carry it, and the ice to keep it edible.
The day before the trip, have a packing day. Invite everyone over again, and have everyone help each other pack. Make sure you try to distribute weight. Even if it means mixing items. Women usually have to be stopped from bringing to many clothes. Men have a tendency to want to bring too many gadgets. Stick what you need to survive in one pile, and what you want to be comfortable in another. Make sure everyone has their "survival gear". (For example I think a first aid kit, some water purification tabs, a glow stick, a striker (fire starter), a compass, a knife, some rope, and toilet paper are survival gear).  I would want everyone to carry that themselves. Yes, that means there 6 first aid kits. No one ever dies from too many bandages. (But again a small kit is all that's needed.)  Then look at your comfort gear. Split it up so the weight is even.  Get everyone into their pack, and have them walk around a bit and make sure they're ok with the weight and nothing is off-center.
Starting out
Once at the start of the trip, go over some safety info. Point out the ranger stations. Make sure everyone knows which way to walk and how to tell. Set up plans for being separated - both for the daytime and the nighttime. Go over the very basics: don't leave food about, keep your tent closed, keep clothes in your tent. Don't drink "raw" water. Go over what to do if someone is injured. Give everyone a map of the area you're hiking in and point out landmarks. See that big rock. That's this spot on the map. See that hill over there, here it is on the map. The river, that's this line right here. If you get lost, then you sit still and wait one hour. If no one finds you by then, you want to walk towards the river and then follow the bank to the big hill. You will either come the camp site or the ranger station.
Camping
Picking a campsite is easy; just make sure it's by a nice big landmark. If you're in a place with assigned camp sites then even better.
Setting up camp make sure you get your spot set up first. If you're using a tent, get it up first. Then help the others with theirs if they ask. If it starts to get dark, it may be time to take charge again, but hopefully, you're with friends and you're not being an ass, so if they need help they will ask. In line with being a leader though, you make the call. If it looks like they're headed for a bad situation help them out. Better mad then dead (or injured, or sick).
While camping stay on top of safety issues. Even if it means being a pest. Remind everyone to keep their food and trash away for example. Specially if you're in an area with bears, cougars, etc. Make it a point to turn in early. By now everyone should be following your lead as far as "what needs doing" so take advantage of that and turn in early. A little extra sleep will go along way.
Fire, if they have had no experience, then you just manage the fire. Again it can really depend on where you are, but if you're in a "dry" area, it doesn't take much for a bad fire pit to become a dangerous situation. Last think you want is the rangers showing up because someone got silly with the fat wood. Give lessons, show the differences, but make sure they at least check with you before adding to the fire. It takes a while to know if a log will burn for an hour or all night. If you need more heat to cook or if you just need to wait for more of the wood to burn.
First aid
I know it's gonna be weird, but when you stop for the night, and in the morning before you pack up, make sure to do a medical check. Most importantly, make everyone take their shoes and socks off and check for blisters or irritations. These nasty little suckers can turn a 1 mile hike into a hospital trip, and because there seem only minor, people tend to just "tough it out", when all they really need to do is make someone aware of it, and put on a bandage (when it's early). Same is true for rubbing of pants and pack straps (though just ask don't look). If you catch it when its "itchy", a little water and a bandage will take care of it. If they wait till it's bleeding and hurts to walk....
Toilet
It seems silly, but when setting up camp, when on site, and during your planning meeting make sure to go over it. Different parks have different rules. There not always intuitive or pleasant.
HAVE FUN!!!!
I know I talk a lot about you taking charge. But this trip is supposed to be fun. Keep it fun. Taking  charge doesn't mean being bossy. But it does mean taking responsibility for the situation. Make sure it's fun and not just a day of you bossing everyone around. Help when needed, interject when needed, but mostly just chill and get back to nature.
Answer: I've done this a few times with about 30 people in my hiking and camping group.  My main preparation was in selecting a place that was as safe as possible.  The lake we camped on is surrounded by a loop trail of about 11 miles.  So the first day is 6 miles and the second day is 5.  However, there is an easy to walk, but unmarked, one mile path to a road that leads to the trailhead.  Every time I've done this, a few people need to take the shortcut out and I have a co-host to guide them. The guide then walks another mile to the cars and drives back to pick them up.
We also use the shortcut to carry in a few extras, such as supplies to set up a latrine, a good size first aid kit and a cache of extra potable water.  I want this to be a moderate experience of backpacking for my friends, not a chore for them.
The campsite has access via a forest service road with a locked gate.  I prepared instruction to give to emergency responders on how to drive to the site, if needed.   And I let the US forest service office know we will be at the site. It is a good idea to have the direct dial number for the proper emergency services in case 911 (or similar) does not work at the location or directs you to another county's service.  If you do not know that cell service is available at the campsite, determine where usable service may stop on the way in or scout out the surrounding area's service availability in advance.
Answer: Been there, done that. Everyone survived, but one had to get plucked off the cliff by a chopper.
Ditto Karen, apnorton, & dirt. Unpack together before trip, repack together. Pack 2-3 heaviest items within easy reach so you can exchange them depending on who's struggling to keep up. Be ready to carry all the heavy gear and extra water yourself.
Also be sure to stop 1 mile in, make everyone take off their shoes to check for hot spots, and apply moleskin now. Newbie campers--even runners--usually don't recognize pre-blister hot spots. Your shoes wear differently with a pack on terrain vs. running on flat.
Also grill them repeatedly on basic survival, before and on the trail: "If we get separated or lost, what are you going to do again?" Make a joke out of it beforehand. Tell them you'll just be asking it to see how they're faring on the "death march." But you need them to constantly be thinking about their response so they don't run or follow equally foolish "instincts" when they get surprised/adrenaline. Telling true good/bad stories is a great way to do this.
Beware the prideful ones. They're quickest to take off in a dead run when they think they've lost the trail, rather than stopping to reconnoiter.
Answer: I am assuming you go with adults.
They are adults and you don't need to babysit them. Tell them what to take and what to not take, but gear inspection or packing for them? The %&$*? If someone is insane enough to go on a snowy 2500m high mountain in sandals (twice!), it is his problem.
1.) Make the trip interesting. This is by far the most important part of the thing. Nearly getting them killed - they will at least have stories to tell, even if they never go again. An easy 10km trip on the forest trail, sleeping there and going back will be likely boring enough they won't consider going out again.
2.) Too difficult, not enough food, not enough water? You will manage somehow. But don't go crazy. A 50 km trip in 2-3 days over few mountains (2000m height difference per day) is a nice starting experience if they are in reasonable shape, even if they aren't really used to walking. Just make sure an abort is possible at any time - "rescue" needs to be at max few km away. Plus possibly 10-20km walk of one person to get the car, or calling a cab or some other friends to get you all out of there. But if they barely manage to walk 5km on a flat surface without backpack, it is best to simply not go on an overnight trip yet. Find a nice easy 2hr walk to destination and practice on that.
3.) For a short trip, food is mostly irrelevant. 2-3 days hiking without any food won't kill them, but they will be hungry, tired and easily annoyed. Won't be a nice experience for anyone. Ask them to grab sugary snacks, to eat breakfast before you go and pack a few sandwiches and some fruit. Tell them to not take fatty and salty snacks (chips, flips etc). Water and other drinks are more important. Ask everyone to bring about 2l/day. Mostly water, maybe a bottle of a sports drink. This is also why trip should be short - 1 week requires tons of water or searching for streams.
Other stuff they need to take? A towel, spare clothes, medical plasters (preferably blister ones). Sleeping bag depends on the area and weather. In spring/summer can usually go on a trip without and not freeze. If they take it, they should have a light and small one for spring/summer. Not a winter one. Too warm, too heavy.
It is very likely they will try to take too much stuff on the first trip or forget something. Put a lot of emphasis that every kilo counts and that you will all stink together :)
You should pack all they do, bandages and other wound treating stuff (disinfection, soothing etc), extra chocolate in the morning to get them going, tent of course. Maybe flashlight, compass, map (phone can replace these 3, as long as it is charged :) ).
4.) On the trip, make sure you all stay together at all time. Never give permission to go ahead or stay behind, unless the destination is in sights.
Make the first stop early enough, say after 30 minutes. Ask them how it is going for now, and ask them to check their feet if there is anything red. Put plaster on the area. Then stop every 2-3 hours for several minutes and check their condition.
Make sure you are setting up tent early enough.
Answer: Hmmm, people with no real experience, no cardiovascular fitness, no strength to lug a pack around, no navigational skills, I would say heck no. The first time we did it we almost bought the farm, got lost with no gear, no winter protection and we were only a bit more than a mile away from town. It was not our fault, the Ranger gave us wrong directions and sent two newbs through the forest with less than an hour of sunlight left. A forest with bears, rattlers and gators. The point is, the unexpected happens to those who are not prepared.
They should not be using their first experience for training. Trial and error, that is not the way to go out there. Have they watched the necessary vids on youtube? Are they members here? Your training begins and ends at home in safety, because if you can not do it there you can not do it anywhere.
Does this group know how to stay together, how not to panic if they see a bear? Do they know how to walk around without injuring themselves? How to avoid snakes? Nights get cold in the forest, it was 73 in the day and 38 that night that day. Easy to lose the trail, easy to lose the rest and be stranded.
First timers have no idea what it is like, I suggest take em down a well known trail, walk them down it for about an hour or maybe and a half and then bring em right back to the car and home. That should be more than enough.
Just in case you decide to not follow any of my recommendations the number one thing I can say that you should make sure everyone carries is water! Most first timers will try to get by on 20 ounces of water... Let me tell you this, there is no worse hardship then being short on water. Make sure everyone carries a gallon of it. Then comes the pain of carrying it. Good luck!
Comment: Everyone has to go on their first trip at some point.
Comment: Hi all, I do disagree but thanks for the comments. Home is for practice in my opinion. I have mentioned that, the first couple of trips are just a dayhike. When you are ready then you go out there.
Comment: @Charlie Brumbaugh, I think the OP knows her group is not ready, else should would have not needed to post here. I think other posters also feel it too. It was suggested to pack their bags for them... These people are not ready to practice outside, they have not practiced at all. It is conceivable they could have a first experience as bad as mine. It will change them forever.
Comment: If the guide is knowledgeable enough, and makes sure that the members are properly packed and ready, there is no reason why a short (3 mile in/3 mile out) type hike couldn't be done, similar to what was suggested in some of the other answers.  My scout troop would do something like that with 11-year olds as an introductory hike. The OP also did not mention anything about their fitness, only their hiking experience.
Comment: I agree, I mentioned that. But I got the feeling that the OP is a bit unsure about babysitting several people as I would be. Maybe Coty Lundin could and would do it but I prefer partners who can handle themselves.
Comment: Eh, I'd give them more credit than that since they've at least hiked before and OP says they're enthusiastic. I went on my first solo backpack on a whim, overpacked, out of shape, and still had a great time. Enthusiasm and proper trail selection can make up for a lot.
Comment: Yep, hour and a half in and hour and a half out as I said should be more than enough. Down some beginners trail, nice and wide, places to stop, not too thick with brush on the sides and plenty of dry hard ground. They will all sore and safe and happy the next day


PC Shutting Down Without Warning

Question: I have a Windows 7 PC that is shutting down without warning, seemingly at random.  Here are the symptoms and notes:

PC seemingly turns off completely.  After taking off the cover it turns out the fans continue to run after this happens.
After this happens, the power button light turns and stays orange (it is white while running and dark while powered down).  I can't restart the machine without unplugging it and plugging it back in.
No warning messages of any kind.  When I have had overheated PCs in the past, I have usually seen a heat-related warning message.
Happened so far when browsing the internet, while idling, while booting, while running a diagnostic test (the one at start-up that is built into Windows).
Fans seems to work fine.
I ran a thermal test program on the box, and the highest readings I saw were GPU (68C) and "temp3" (62C).  I have no idea what "temp3" represents.
No changes have been made to the PC recently (software or hardware), outside of a minor move (really just sliding it about 3 feet a few days ago).

I realize that this is impossible to really diagnose via ServerFault--I am looking for help in steps I can take to diagnose the problem (programs I can run, etc.).
Thanks for any insight.
Answer: Almost certainly a hardware problem. Get a diagnostic tool from your vendor and run it through. If you cannot get something like this, at least run something like memtest provided by most Linux versions, which you can run by getting a lived. If it is in warranty, it is best to ask for vendor  service.

PC Shutting Down Without Warning


What exactly does the holographic principle say?

Question: Does the holographic principle say given a spatially enclosing boundary satisfying the Bousso condition on expansion parameters, the log of the number of microstates in its interior is bounded by $\exp\{A/4\}$ where $A$ is its area? Or does it say something stronger, namely the state restricted to the boundary uniquely determines the state restricted the interior? Can we have the former without the latter?
Answer: The holographic principle is a stronger proposition than the entropy bounds but what is the strongest possible formulation that is still valid is disputable. Nevertheless, some facts are well-known.
The entropy bounds say that the maximum number of distinguishable microstates that may describe the interior of a region with a fixed boundary is $C\cdot \exp(A/4G)$ where $C$ is some subleading, non-exponential correction (or exponential in lower powers of $A$). The entropy bounds hold for light sheets etc. that satisfy the appropriate criteria – which of them are the "best ones" is a bit disputable, especially for time-dependent spacetime geometries (which were the focus of Bousso's work: Bousso wanted to generalize previous, much older results on the entropy bounds from stationary to time-dependent geometries and to some extent, he succeeded, although it's not clear whether his particular prescription is unique or canonical in any sense).
However, such entropy bounds are largely classical in character – they pretty much say that the objects with connected event horizons maximize the entropy and nothing else.
The holographic principle, as originally formulated, was and is meant to be a stronger proposition than the entropy bounds. It says that not only  the number of "bits" needed to describe the interior is bounded by a linear function of the surface area; in fact, there exists a "natural" theory living on the surface area that is fully equivalent to quantum gravity in the interior even though the surface area has a smaller dimensionality (by one)!
I used the adjective "natural" because the theory on the surface has to satisfy some properties for the statement to go beyond the entropy bounds. Why? If we allow the theory on the boundary qubits to be "arbitrary", we may write down any Hamiltonian as some complicated operator on the space of all the qubits, assigning any basis vector of the Hilbert a general linear superposition of the basis vectors.
It's always possible to write down a Hamiltonian on the Hilbert space of a given dimension as "a theory". However, in general, such a theory will be totally nonlocal. The ordering of the qubits along the surface will generically be just a bookkeeping device to remember the number of the degrees of freedom but the Hamiltonian won't respect the arrangement in any way.
To make the holographic principle stronger than the entropy bound, the theory on the surface has to be required to be "natural" which ideally means "local". Indeed, this is exactly the case of the AdS/CFT correspondence where the boundary sits at infinity of the AdS space and the dual conformal field theory, CFT, is indeed exactly local.
However, there are no known examples in which the boundary would be at a finite distance. It's rather obvious that if there were a boundary theory for a finite region, it would be at least somewhat nonlocal because the geometry of the surface is fuzzy, with the fuzziness length scale equal to the Planck scale (or much longer than that). The local character of the CFT in the AdS/CFT probably depends on the infinite scaling of the metric: infinitely short distances in the CFT theory may still correspond to finite or large proper distances in the AdS space (because they're distances between points near the boundary at infinite where everything is long) and that's why we get locality.
All the known versions of the AdS/CFT correspondence are therefore the only known examples in which the holographic principle in the form saying something about the actual "theory on the boundary" – i.e. saying more than the entropy bounds – seems to be correct.
Answer: There's no a priori reason why we can't have the former without the latter. The stronger version was only introduced to resolve the black hole information loss "paradox".
Answer: The stronger version violates the no-cloning theorem of quantum mechanics. The only way out is complementarity a la Susskind, which is extremely radical.
Comment: It is not radical, it is well accepted. The interior and exterior of black holes are not separate places.
Answer: I have to agree with Hunter's answer. But let me elaborate on it.
A proposed way to get around the no-cloning objection is to assume there is an orthonormal preferred basis (different from the preferred basis of the measurement problem) for boundary states, given by $\{|\chi_\lambda\rangle\}_{\lambda\in C}$, and for interior states, given by $\{|\psi_\lambda\rangle\}_{\lambda\in C}$ for some set $C$ such that a generic state is given by $\sum_{\lambda\in C}\,c_\lambda|\chi_\lambda\rangle\otimes|\psi_\lambda\rangle$. However, this breaks rotational invariance. Consider a spherically symmetric boundary with a massive spin-s particle right at the center of its interior. s is taken to be nonzero. Any choice of basis will have to explicitly break this rotational symmetry.
What complementarity says is there are two "pictures". In one, there is just an interior description with no extra states at the spatial boundary. In the other, the interior is removed and replaced with a stretched horizon boundary with additional horizon degrees of freedom. Both pictures are each internally consistent by themselves, but can't be mixed (or so claims Susskind). It's not valid to consider the interior and the stretched horizon simultaneously. That would only violate no-cloning. In the same manner, it's not valid to remove the interior while not including the stretched horizon. That would only lead to a loss of information, as well as Hawking radiation coming out unpredictably from the boundary.
If there is a stretched horizon, the degrees of freedom on it are not like that of a local quantum field theory. This has been argued in Susskind's articles on fast scrambling. Information falling to the stretched horizon has to be "reflected" within a time period of $R\ln(R/\ell_P)$ or so where $R$ is the black hole radius in a "maximally scrambled" manner. A brane with local QFT degrees of freedom and no superluminal interactions needs more time to scramble. Contrary to what Susskind thinks, this actually strongly argues against black hole complementarity.
Also, complementarity, if it holds, might not apply to any spatial boundary satisfying covariant entropy bounds. In Susskind's version, it only applies to stretched horizons hovering a Planck distance above the event horizon. In the AdS/CFT correspondence, it only applies to spatial boundaries at the conformal boundary. It doesn't apply to enclosing boundaries in between.


Bitcoin taxes question for USA

Question: If one were to receive Bitcoins then immediately use a conversion service (for example to PayPal) would gains/losses need to be recorded?
If so, is there any software that can do this automatically?
Thanks in advance.
Answer: Bitcoin is taxed as capital property (see IRS Notice 2014-21), and a tax event occurs any time it is converted into fiat (e.g. USD) or other assets. You would have to record each transaction and include it in 1040 Schedule D.
This is the difference between how much USD you received less the value of those BTC when bought/acquired them. If you had owned those coins for more than a year, you can report it as "long-term" gains, which has a reduced tax rate. Otherwise, it "short-term", which is just taxed as normal income.
You can use https://bitcoin.tax to help work it out.
Answer: Both mybitprices.info and LibraTax are both websites that can automatically generate schedule D reports for bitcoin wallets or single addresses.
bitprices is the open-source software behind mybitprices.info and can be run on your own computer.

is there any software that can do this automatically?
Answer: Income is income if you make a gain it would be reportable on your taxes regardless of amount.  I am not aware of any software currently that tracks income gained/lost based on current bitcoin prices, but it should be trivial if someone owes you $200 and they send you the BTC equivalent and you hold it for a short term and when you sell you get $220 the $20 increase in value would be reportable as short term income.  Also I am not a lawyer  and this does not constitute legal advice always consult a lawyer and an accountant for specific local regulations that may or may not apply to your situation.
P.S. the $600 limitation is placed on businesses when they determine if they need to send out a 1099 form or not.
Answer: If it is a transaction under $599 it shouldn't be taxed according to tax law.  I'm not a lawyer.
Comment: "It is a common misconception that if a taxpayer does not receive a Form 1099-MISC or if the income is under $600 per payer, the income is not taxable. There is no minimum amount that a taxpayer may exclude from gross income." https://www.irs.gov/uac/Reporting-Miscellaneous-Income

Bitcoin taxes question for USA


How to change smart object outlines and colors?

Question: I was wondering if there is a way to alter the color of the Smart object that has been inputted into Photoshop. Basically, I have a series of glyphs that need  to be altered so they  have new hexadecimal's. Is there an easy way to do this? There doesn't seem to be any Photoshop functions available?
Answer: Highlight the Smart Object in the Layers Panel.
Choose Layer > Layer Style > Color Overlay.
Set the color overly blend mode to "Normal" and 100%.
Click the little color box, input your hex value, and click OK twice.
Comment: @KMSTR With Photoshop CS6 it's **even easier** if you apply the layer style to a Layer Group (folder) in the Layers Panel, then you can just drag layers into the group and they are instantly colored.
Comment: In addition, with this method you can copy the layerstyle and paste it to other smart object layers. Making recoloring of large iconsets very easy.
Comment: Sounds good. I will try that once I get my hands on CS6. I only tried the demo. What dissapointed me was that I couldn't use shapes in combination with fill and gradient layers anymore. I suppose thats done in the same way as applying layer styles now?
Comment: Sure you can. In fact they are better in CS6 because they are true vector layers. Control bar has a fill and stroke option similar to how you'd fill and stroke in Illustrator.
Comment: Perfect. thank you so much that was simple and effective.
Answer: For # smart object outlines and colors?
  -- Ctrl + Click the particular smart object layer.
  -- The outer layout is selected
  -- Now right click or choose form EDIT menu > Stroke and give the color and stroke type.
  ** make this stroke things in separate layer so that u can change color later thr blending   option


I want to know about Ubuntu basics: shell, command  etc about Ubuntu. help!

Question: I'm new to Ubuntu and I want to know some basics about Ubuntu/Linux, because I don't understand command line, shell, etc. Would anyone please explain about ubuntu shell, command and what's the meaning of ppa and repositories in applications package?. I'd be glad if you want to answer my question here or to firstname.lastname@example.com.
I love ubuntu since 3 days ago when I migrated a new operating system to linux and I think Ubuntu is the best for beginners like me. But I have to learn more about linux cuz this one is so different and more fun than Windows.
Thx...Thx!
Answer: The Ubuntu Manual project covers what you want to know and much more, all in an easy language with lots of screenshots.
Answer: There are wonderful resources available on the web, specially in Youtube.com search for the term "ubuntu tutorials for beginners"
Videos by NixiePixel are highly recommended.
Another great resource is http://showmedo.com/ teaches you step by step most major open source programs, including Ubuntu. Have fun!
Answer: Since Ubuntu is a beginner freindly Linux Distribution, there is plethora of resources available for answering your question, First I suggest you read the Ubuntu User Guide here
You can look through the Index of the book and find answers for the specific questions you have. But I recommend for you to read the book cover to cover if you can.
OR
You can Google each of your questions and it will show you how often a variation of your question or the exact same question been answered before.
Hope this helps.
Answer: My main suggestion sounds silly but it worked/still works for me: Break things! Seriously, try things out and if your set-up gets broken be prepared to start over. You'll learn a lot in this fashion.
Also:

Open up a terminal and read the man pages of various commands e.g. type man mount and thoroughly read it. man pages are full of good information.
Take a look at tuxfiles. In particular, read through the tutorials on things like /etc/fstab and APT.
Try and grasp what each part of a command is meant to do before you issue it. If you don't know, then read the man page.
Search around on ubuntuforums and on here and also unix.stackexchange.
Install lots of software and play around.

Most of all, have fun!
Answer: I am a bit old school so I stick with books. The way I moved to command line it was this book: http://www.amazon.com/Ubuntu-Linux-Toolbox-Commands-Debian/dp/0470082933/ref=sr_1_1?ie=UTF8&s=books&qid=1303294691&sr=8-1 which provides a clear way how ubuntu is structured and examples that can cover from the novice to advanced user. I read it once to get an idea and run some examples and now I just use it as a reference since its organized in chapters according to the tasks you want to do.
Don't worry about the ubuntu version terminal in the back end is the same.
In cases that internet not available to your server environment (been there), a book is always the solution.
Answer: In addition to the good suggestions already here about resources specific to Ubuntu, I recommend The Linux Documentation Project, which has a lot of good resources. In particular, to start, try Introduction to Linux - A Hands on Guide.


Has the Federation ever forced the Prime Directive on other species?

Question: We all know that Starfleet officers follow the Prime Directive but are they duty bound to stop other races from interfering in other civilizations?  If not, then what stops someone like the Cardassians or the Romulans from taking over pre-warp civilizations?
Comment: Er, wouldn't forcing the Prime Directive on another species be a violation of the Prime Directive?
Comment: @DanielRoseman - Prime Directive only applies to pre-Warp species
Comment: maybe he meant 'enforce' - as in protect a race from being interfered by another.
Comment: This is a valid question.   There should be no downvote.
Comment: @ThePopMachine its the anonymous phantom downvoter.  Assume all questions and answers are +1 of their displayed value.
Comment: @Tritium21: The question does not show any research effort.  A downvote is not inappropriate.  (Although I happen to disagree.)
Comment: @DVK General Order 1 also covers meddling in the internal affairs of other nation states.
Comment: The Prime Directive only applies to actions by the Federation and the Ferengi. 'Cuz the Ferengi are special.
Comment: @Omegacron Doubtful.  See: DS9 - Little Green Men
Comment: Kind of see also: http://scifi.stackexchange.com/questions/54950/who-is-bound-to-the-prime-directive/54963#54963
Comment: And, possibly better, see http://scifi.stackexchange.com/a/54965/440
Answer: Starfleet General Order 1 applies ONLY to Starfleet. The Prime directive does not apply universally inside of Federation space, nor are non-Starfleet officers and non-Federation officials expected to uphold it.  The Federation cannot enforce this even against its own citizenry, if the citizen is not acting as an agent of the government.  To quote Memory Alpha (emphasis mine):

The fundamental principles were an important part of Earth Starfleet procedures as early as 2152, but it did not go into effect as a General Order until sometime after 2168. (ENT: "The Communicator"; TOS: "A Piece of the Action") The directive remained in effect well into the 24th century and applied to at least Starfleet and Merchant Marine personnel, but specifically did not apply to ordinary Federation citizens. (TOS: "Bread and Circuses"; TNG: "Angel One")

Again, the Prime Directive is Starfleet General Order 1.  The Federation cannot even fully apply it to itself, let alone other nation-states.
To extend this to answer the question as asked; A Starfleet officer cannot themselves interfere in the inner workings of another society or make contact with non-warp capable races.  They cannot prevent non-officers from doing so, nor can they really do anything about it when one nation-state does so against another.  Also, the nation-states you specifically mention have done what you asked about.
Answer: The Federation claims political sovereignty over a three-dimensional slice of the galaxy.  Within this domain, they do not allow any encroachment by foreign powers, either on planets or just floating in space.  While there is some allowance for overlap with truly alien beings who do not require the same environment as humanoid species, in general if you're "in federation space" you wind up constrained by all the rules of the federation, as you either joined the federation or are there are their sufferance.
Outside of federation territory, this outlook is not shared by all space faring races.  The Ferengi, for example, actually held out the Prime Directive as proof that the Fedreation were barbarians when arguing with the last guardian of the Tkon, as they denied lesser species access to their technology (and thus denied themselves their profit.)
Comment: There is an excellent argument against the Prime Directive in the *Star Trek* novel, *The Fate of the Phoenix*, actually. The titular Phoenix, Omnedon, was part of a species that achieved warp travel, and were therefore contacted by the Federation. When his people, disturbed by proof of alien life, descended into civil war and their world was destroyed, leaving Omnedon as the sole survivor, he escaped and became one of the few well-known Federation citizens - posing as a human named 'Omne' - to argue against the Prime Directive. He argued, like the Ferengi, that it was barbaric and selfish.
Comment: @Craig: The Son'a enslaved two pre-warp species while building their empire, and the Federation knew about it. So presumably not. There is also evidence, from novels and comics, that both the Klingons and Romulans enslaved pre-warp civilisations without Federation interference. Cardassia occupied Bajor when it was pre-warp. It seems that, principles aside, the Federation wisely avoids directly confronting powerful neighbours over their policies. They are no different to most governments in that regard; it's not like the US is rushing to defend Ukraine right now.
Comment: So if a warp capable species, such as the Ferengi, where to enslave a prewarp civilization that is outside of Federation territory, would the Federation intervene if they knew about it?
Comment: @JamesSheridan: Russia is hardly "enslaving" Ukraine.
Comment: @LightnessRacesinOrbit: The point. Missed it you have, hmmm? The West routinely criticised Soviet human rights abuses, yet did nothing to intervene. Arab states deny Israel's right to exist, yet haven't lifted a finger about it since the Yom Kippur War. Most countries denounced Nazi treatment of Jews, yet did nothing to help. The simple fact is that states, whatever their principles, seldom defend those principles in the face of a powerful state which differs.
Comment: @JamesSheridan: I did not disagree with any of that.
Answer: I think the best evidence that this can happen is that the Son'a went through the whole song and dance of hidden observation of the Ba'ku, despite not caring much for it, and presumably this was a condition of their partnership with the Federation.
Of course, in reality, the Prime Directive was about to be broken in a rather fundamental fashion by both parties, but this was a concealed, clandestine activity and cannot be deemed to represent any sort of legitimate Federation policy.
Note that the planet Ba'ku lies within Federation space, so Insurrection doesn't tell us whether the Federation would (or would be able to) impose the same conditions on missions outside of their territory.
Answer: The concept of "Federation Space" leads one to think in planetary terms.  When something or someone, is outside of federation space, they may be separated from interaction by months or years of travel.  Space is huge, and no political entity could ever police all of it.  The 'Prime Directive' seems to apply to Starfleet and its personnel, with those outside of it, even federation citizens, not particularly concerned with it.  One sees many violations of the rule in various episodes, but usually the most flagrant are those by non-federation or at least non-starfleet persons.  In the original series, a highly advanced race took it upon themselves to end a war between two lesser species simply because the violence expressed by these unevolved beings was painful to them.  This translates to a violation of the prime directive on their part, even though the races in question had warp technology.  I suspect that in the Star Trek universe there are more than a few lawyers who make a good living off of the 'prime directive'.  Insofar as imposing it on other civilizations/races the federation has more than enough trouble enforcing it among their own citizens, without reaching out to others.


Where in the Tripitaka completion of the formation of Karmic result is mentioned?

Question: For Karma to be complete a certain set of conditions need to be present. What are the Suttas / Abhi Dhamma in this these sets of conditions presented in? Do Suttas / Abhi Dhamma mention what happens if some of the conditions are not met (but volition is present)? What are the instances where the completion of the Karmaic result or fomation is mentioned regarding morality and precepts, i.e., the necessary and sufficient conditions to transgress each or the 5 or higher precepts on which the Karmic result become complete?
Answer: I think that the "conditions to transgress precepts" are spelled out in the Vinaya in great detail. For example, in The Buddhist Monastic Code I: The Patimokkha Training Rules Translated and Explained,

Pages 245 through 247 define what "a lie" is
Pages 54 through 74 define "stealing"
Pages 75 through 85 defining "killing"

And similarly for other (monastic) precepts.
Comment: +1 this was what I was looking for but I am keeping the question open for the time in case there other citation in the Suttas and Abhi Dhamma.
Answer: Upasaka Suminda Sirinath S. Dharmasena,
The simply Sila section (or point of view), especially the Vinaya section does not answer this question in a valid way, since it is a "Abhidhamma" question. Vinaya does not always "judge" on the level of cause and effect on that level, but has also certain "will to exist" as its perceptive (one is to maintain a long life for the Sangha). Atma guesses that this matter was actually the reason for your question, now finding that Upasaka is brought back to where he actually came from.
If one looks into Vinaya more deeply one would find many occasions where such as intentions does not seem to play a rule at all. Also the factor of "deliberate" is not well explained and gives a lot of place for hypocrisy and in-honesty.
Classical Abhidhamma, where such things like factors are taken from, do also easily misguide since they give a lot of anchors for defilement to seek for justification as long as ones mind is not really trained and able to be most up-right in matters of judgement.
Atma guesses, that "simple" and profound Suttas like those
dealing with the matter of "Accepting = instigate = doing by one self" shows why the matter is not so easy to be carried, by those who like to put Dhamma into ones way of life and not vici versa. ( 6. Acelakavaggo AN03.157-163, , (17) 7. Kammapathapeyyālaṃ, translated by Ven. Sister Uppalavanna (For examples please see links)
Another often appearing mistake is to make inversions of arguments. Most famous are sayings like "but this does not matter for laypeople", when certain thinks have been taught as fault for a Bhikkhu. Such is in now way generally valid. Cause and effect, at the end, do not really care about your current assumed livelihood and knowledge.
So it needs good investigations of which has certain impacts in your current relations (generally called fault or transgression) and what is actually kusala or akusala, meaning that it has impact beyond your current relation and will ripe anyhow somewhere.
Since the question was on the level of Abhidhamma, or real higher virtue, Atma suggests Upasaka Suminda Sirinath S. Dharmasena, to leave this question open for a long time, since it is a straight line to insight and most beneficial to investigate.
So actually totally misleading interpretations, comings from inversions of the original sources.
The missing of a confession, if one does a miss-deed, might be founded on the famous Instruction to Rahula
Against verbal and bodily action, a misdeed here, in the sphere of
mental actions does obliviously not require the direct support of a
kalyanamitta.
One can see here that in the case of bodily and verbal actions, it has always direct impact on ones society and with it, endangers the current possibility of practice and support for it enormously. That is why there are also certain punishments in the Vinaya, to do all possible that one sticks on the good road. As for mental actions only, it would be not possible to get them worked out. So here one is left alone. But that is the reason why especially here should be a lot of explaining, since the actually impact is not different.
So one should remember this if somebody cleans your room from vermins, if it is a good idea to feel "Thanks" or what ever kind of acceptance with it. To guide an potential executor to them or opening the door... such are already certain mixes of bodily verbal and mental actions.


Getting SAGA working with QGIS Sextante

Question: I just created my account on this forum to find an answer to a stupid (?) problem I can't deal with.
First, let's precise I just (some months ago) learned on my own what GIS was, and gave it a try using QGIS. I'm working on Windows XP.
I apologize in advance for my not so good English, and my poor skills (and maybe bad vocabulary) in GIS and kriging.
My problem is:
I need to use kriging to interpolate punctual data from a vector layer (points); this layer is created by me from fieldwork measurements and is in .shp format (try.shp).
I had a look on the internet and saw there were 2 possibilities : use SDA4PP plugin, or Sextante toolbox with SAGA. I wasn't able to have any of them working.
Apparently, SAGA is much easier, thus I would prefer to work with SAGA.
What I have done so far:
I downloaded the last version of QGIS via OSGeo4W (all packages selected).
I downloaded SAGA 2.0.8 from Sourceforge.net (version *_bin_msw_win32), activated it Sextante toolbox, entered the right folder path (which contains spaces) in Sextante configuration.
When I want to perform ordinary kriging, I select the layer, the attribute (which is "id"), ask for a variance grid, target grid is "[0] user defined" (no other choice), I choose an exponentiel variogram model, no block kriging and no logarithmique transformation, and let the default values for the other parameters (especially, grid and variance rasters are saved to temporary files).
Then I click "OK" and get this message error:
Could not layer: C:\DOCUME~1\user\LOCALS~1\Temp\sextante\sagaordinarykriging6fd1782d35df....tif. Check the Sextante log to look for errors.

Here is the error log :
Could not load model watersheds.model
ALGORITHM:ftools:export/addgeometrycolumns

and the algorithm log :
sextante.runalg("saga:ordinarykriging","C:/Documents and Settings/user/Bureau/Kriging/try.shp","id",True,0,1,False,100,False,0,10,100,1,0.1,1,0.5,1000,4,20,1,True,"-55.4887564869,-55.4887477484,-8.61474380806e-07,4.59453003047e-06",None,None)

Any idea of the reason why it doesn't work?

I tried to uninstall-reinstall OSGeo4W using the advanced options. I selected SAGA as a package when reinstalling, but SAGA was not really installed: the tar.gz was downloaded and that's all. I unzipped it, and then I had to enter manually the path, which I chose to be without spaces (C:\OSGeo4W\saga, after having cut-pasted the SAGA unzipped folder at this very place). And ... same as before ... Same error, same behaviour, all the same. Any clue ?
--
The installation worked well, no errors. I precise I removed all the files concerning SAGA and QGIS before reinstalling (with Add/Remove Programs and Search).

It worked !
I really can't explain why, but it worked. Until now, I was working on a self-made point shapefile, with random points with "id" within the range 0-150. Recently I used a file containing real data from fieldwork, and it worked. I did exactly as for the first file, no clue why it suddenly worked.
One more thing. When using SAGA software, I can choose to select a variogram or not; it seems I can't select a variogram using SAGA via the Sextante toolbox, even if I want to. Why ? Is there a way to select a variogram using SAGA via the Sextante toolbox ?
Besides, I guess it's always better to select a variogram (I'm a beginner in kriging).
What do you think ?
Answer: If you are going to run SAGA 2.0.8, then you could just install it from the OSGEO4W installer too.
If you select Advanced Install at the beginning of the installer, later on you can Select Packages and saga: SAGA System for Automated Geographic Analyses is under the Desktop category.
With SAGA installed this way, from the SEXTANTE Options window you don't have to even specify the SAGA folder - the plugin will find them automatically if you just place a check beside Activate.
If you want to work with SAGA outside of QGIS, SAGA can be launched directly from the OSGeo4W terminal by using the saga_gui command or scripting with saga_cmd.

Getting SAGA working with QGIS Sextante


How does domain pre-registration work for the end-user?

Question: I just pre-registered a .guru domain name through GoDaddy, and it just disappeared from the account panel. There are messages and receipts for my payments, but other than that, I have no clue whatsoever about the status of my domain name.
Answer: As with pre-registration for all the new gLTDs like .guru, once the registry for the gTLD releases it for registration, the registrar will attempt to register the domain name for you.
Note that this does not guarantee that you'll be the registrant (aka., owner) however, as each gLTD registry may have several registrars underneath it, and each registrar can have several pre-registrations for the same domain name.
As GoDaddy indicates here in its FAQ:

Does pre-registering a domain guarantee I'll get it?
No. Pre-registering a domain reserves your place in our queue for that
  domain. The instant the registration phase opens, we'll submit our
  list of registrations electronically using our industry-leading
  technology to give you an edge.
If we are unable to get the name, we'll refund your registration cost.
  Any application fees that may have been collected for the Priority
  Pre-Registration and Trademark phases will be non-refundable however.
  There are no application fees for the standard Pre-Registration phase.
  Application fees will vary by domain.
If GoDaddy secures the name and more than one person or company has
  pre-registered it, all parties will be invited to a private auction to
  decide who gets it.

If they are successful in securing the domain name, and it doesn't go to a private auction, as in the case where there's multiple parties involved (see above), you'll receive an email confirming the registration for the domain and you will be listed as the registrant in their WHOIS database.
Until you're the registrant for the domain however, it won't be displayed under your Account Management Domain Control Panel.
Note that as to when this occurs is up to the registry for .guru, which is Donuts (Pioneer Cypress, LLC), as indicated here. You can periodically check their TLD launch schedule here and news here.
Update:
As indicated on several Donuts accredited registrar sites, the .guru gTLD appears to be available for registration now, so you should receive an email soon in regards to your pre-registration status.
Also, here is a link to a GoDaddy support document about .guru domains, along with more information about registering Donuts Domain Names.
Answer: .guru domain name is one of the new domain extensions. GoDaddy pre-registration increase your chances for getting this domain if it's still available. GoDaddy submits your pre-registration the moment each phase opens. You have to wait till the extension is released worldwide.


How often to reboot raspberry and is it even necessary

Question: If you have a raspberry on some location and it must run a python script "forever" (a year, maybe two, without me being on location), how often should I reboot it? I know people are keeping them alive for a year+, but I wrote a simple script that can reboot it at given time + raspberry will automatically run the python script on boot.
Comment: In the context of IT support, you presumably mean "in 90%" *of problems* reboot helps.  You would not call up a customer at random and tell them to reboot now just in case ;)
Comment: Just check your logs and other growing files: logrotate will do it. SD cards have a limited lifespan on heavy loaded disk activity, maybe move /root to use external spinning drive. I added a blinking led in sync with cron and a red that lit when disk space is low and other that lit on some security log info, trimmed rsyslog to the min.
Comment: Why reboot if you don't need to? There are times when a reboot may be needed system upgrades for example. but if this is not automated I would not reboot. A reboot is not free of the risk that the system will not reboot successfully.
Comment: 24/7 datalogging on Arch, current uptime 260 d. Usually rebooting leads to trouble ;)
Comment: The one I run 24/7 has an uptime of 67 days right now, which is probably not unusual.  I only reboot it for a purpose.  As Steve says, why do it without any purpose?
Comment: Well I also work at IT support and in 90% reboot helps so I thought maybe I should do it to prevent errors. Nevermind then.
Comment: Yeah true true, you are right. I'll probably make it "remotely rebootable", since rasp will talk with webserver.
Comment: Sounds similar to this problem: https://www.youtube.com/watch?v=6dmhF1rqaZk
Answer: I've got a couple of Pis running my Ham Radio repeater and irrigation system - realistically, I'm rebooting them maybe once every 6 months for security updates or some other "maintenance" reason; but I've not seen issues where a reboot was REQUIRED to "keep things running"
Answer: In terms of hardware, the only reason you should ever need to reboot an ARMHF-y board is firmware changes, necessary changes to ROM, or possibly new devices that must be present at boot.
For instance, adding a driver or close-to-metal kernel module and a device implementing that driver will probably need a reboot, just to tell the CPU and kernel memory mapper about the change. You can update the Linux kernel without rebooting.
In terms of software, all the major computing environments available for the Pi are *nix-like1, in that they're True Unix™ or in that they use Linux or a Linux derivative and are thus (U)nix-y.
Unix and its derivatives are designed from the bootloader up to userland to be fully scalable, portable and reliable; they were designed for servers that never or almost never undergo a hard reset (aka being fully shut down and cold-booted from scratch), and, to a lesser extent, embedded devices exactly like Raspberry Pis. Consequently, these goals indeed apply on the Pi.
This means in practice, you basically never need to reboot your Pi (or your *nix desktop PC, for that matter).

1Ignoring, for a moment, the Microsoft Windows 10: Internet Of Things Edition for the Pi, which I wish to be a practical joke but isn't.
Comment: Thank you for your 2c, it helped a lot, I am now sure I will never reboot my PI.
Comment: Reboot NTs once a month? How do you come up with that?!
Comment: @pjc50 Wow, didn't realise there'd been more recent releases for it. While I was wrong about that, I know that Win10 IoT is same core as Win10 and not CE :)
Comment: Kernel / device modules upgrades are the only likely causes for needing a reboot if the hardware is not changing - and it is getting possible to change modules without restarting these days if I understand things correctly.
Comment: @SlySven you *can* change modules without a reboot, just don't rely on them being fully properly functional and nondestructive
Comment: There *used* to be a bug (back in the 9x days) where Windows wouldn't stay running for more than 49.7 days due to how high a 32 bit counter could count (and the number of milliseconds). Now the only issue is around the 497 day mark (https://www.ctm-it.com/it-support/blogs/matt-cannon/2013/497-days-of-uptime-kills-windows) which, if you're running updates regularly, you're unlikely to hit
Comment: Win10 IoT is probably derived from WinCE, which is perfectly capable of staying up for years. Unfortunately it's very hard to patch for security.
Comment: @pjc50 Win10 IoT is Win10 based (they all are now). The WinCE line no longer exists
Comment: WinCE is still alive and shipping as "Embedded Compact 2013"; in fact for popular chips such as Freescale iMX the latest available BSP is WinCE7: http://www.nxp.com/products/microcontrollers-and-processors/arm-processors/i.mx-applications-processors-based-on-arm-cores/i.mx53-processors/windows-embedded-for-i.mx-applications-processor:WEIMX
Comment: @MatthewSteeples I wasn't aware they'd since fixed that; I haven't used Windows since ME anyways.
Answer: With embedded "run forever" systems, periodic reboots are unnecessary.  It is common to use a hardware watchdog timer to detect a system hang and reboot.  I believe the watchdog timer is more valuable than a periodic reboot (the reboot probably won't work if the system is hung).
Answer: I agree with the things written before.  In a theoretical situation with excellently written software with perfect error handling, no memory leaks..., a reboot won't be neccesary.
I have more than 50 PI's (all PI 3) on site, and some get rebooted weekly and others never...
Almost all of the PI's are used in kiosk mode, either playing videos, displaying a website, running scripts,...  User expercience is important to me and I can't afford to have a PI failing.  I have a watchdog installed on all of them.
On my site, I'm using the following approach (this is only using my own experience, no scientific background :-))

PI's that run servers (Apache, SIP,...) and are only connected with an ethernet cable: I never reboot them, some of them have an uptime of almost 2 years (indeed, I didn't upgrade those)!
on the contrary, PI's that run videoloops (using OMXPlayer):  I reboot those devices weekly. I've tried to not reboot them at all, but I discovered that occasionaly the video hangs without watchdog even noticing.  So one would see a still image on screen.  I'd say that during a one month period there was -for each of the devices- roughly a 50% chance that the video would freeze once,
To minize those risks, I decided to reboot once per week and the results are acceptable: so far, after a year of weekly reboots, I only had 2 freezes (image freeze, no PI freeze).  Of course I would love to eliminate those as well, but this is another topic.
For those, I don't care about the impact of a reboot on the SD-card, since, if this would ever occur, it is simply putting a new SD-card and update the template with the right video.
PI's that are in client mode and display web-based user content (using Chromium, KWeb,...) with user interaction (primarily touchscreens and/or buttons): I reboot those every month and so far haven't had any issues.  Maybe it was not needed to reboot them... but given those devices run scripts (Java, Node.js) and get input from other devices I thought that at some point a reboot might be needed, so I decided to go for a monthly reboot.

I realize this is not giving a direct answer to your question, but I just wanted to share some personal experience so you can -together with the other answers- judge what the best approach for your project would be.


Migrating from foo.com/wordpress/ to foo.com/ -- how can I do it?

Question: I have a working wordpress installation at mydomain.com/wordpress/index.php (not a real domain). I want to migrate it to mydomain.com/index.php. How can I do that? I tried just unzipping a new copy of wordpress in the main domain space and copying over the config file, but I don't think I got it working, since it's not even giving me an error message--just a blank screen. Furthermore, going to mydomain.com/wp-admin/ seems to automatically redirect me to mydomain/wordpress/wp-admin.
Answer: You have to change Settings -> General -> WordPress Address (URL) and Site Address (URL) in the old installation.
WP looks in the DB at these settings and creates dynamic links, etc, from there, so you need to change it in the DB (either through these settings or by editing the db manually.)
Another option (and, actually, the better one) is to use a plugin which changes the links in the entire db - this will keep all of your links, images, etc. working properly.
I've used Velvet Blues Update URLS before many times, and it works perfectly. http://wordpress.org/extend/plugins/velvet-blues-update-urls/
Just remember - if making this change with the WP backend (through the settings page or with a plugin), you should do it on the old site. Then it should be immediately accessible at the new location. (Or you could just move your files to the new location, preserving your themes, media, etc.)
Answer: First, you might want to read prior answers to this question.  Start with this list.  Also, have you tried restoring the original wp-config.php file to see if it would bring the site up?
Second, what steps have you taken to update the database for the new install location? Did you export the database for the old location and import it to the new location's database?
Third, if you have imported the old data into the new database, did you take any steps to update the new database with the correct, current URLs? Wordpress databases contain several full path URL entries which you may need to update.


Why should the user ID and group ID of every file match an existing user?

Question: I've been reading in most hardening guides for Linux, that you should check for files and directories without valid user or valid group. What I can't find, is how this could be used for an attack, or how this could be a weakness, besides it being "improper".
Answer: Files always have a owner-id and a group-id. But if the files are copied from another system (e. g. extracted from a tar archive), there may be no name assigned to those ids.
At a later time a new user or group may be created which gets the next available id. This id, however, may be the same id as the one used improperly before.
As a result the new user/group gets access to those files.
Comment: but how does that affect security? From your answer it looks like the only downside is, that a user gets the files of another user (which is bad, but still, I was wondering if there are bigger implications)
Answer: Every file should belong to a user or group, for the primary reason of enforcing file permissions.
A basic but very key concept of protecting a system is the principle of least privilege: allow users minimal access needed to get the job done.
For example, your web development team might need access to your /www directory, but they should not need to have access your system files. Setting up proper ownership and access control for your files makes it easier to enforce the principle of least privileged by limiting the amount of access each user is allowed.
Comment: (Cc @user857990) While true, this doesn't seem to relate to the question. The principle of least privilege implies checking that files are only accessible to the principals who are supposed to have access. This means looking at both ownership and permission, but it applies to all files "with" users and groups.
Comment: The answer does not even relate the question.
Comment: thanks, enforcing file premissions was what I was looking for.
Answer: The wording of this question is a bit strange: each file belongs to exactly one user and exactly one group. Each file has separate sets of permissions (rwx) for the owning user, the owning group (minus the owning user if he's in the group), and others. It's impossible for a file not to have that one user and group.
If the filesystem has ACLs, there may be more users and groups with specified permissions on each file.
Users and groups are encoded as integers in the filesystem. These integers are called user ID (uid) and group ID (gid). The association between these integers and user and group names lives at a higher level, they are provided by the standard library. The associations are recorded in local databases such as /etc/passwd and /etc/group, and in network databases such as NIS and LDAP. These databases define the scope in which a user or group is valid. Generally that scope is the local machine for a local database and a network of machines using the same database for a network database, but there is a lot of potential for more complex situations; for example it is common to have system users with a per-machine scope and real users provided by a network database and shared over many machines.
Occasionally you may see a file that belongs to a user or group that doesn't have a name. There can be many reasons for this, but most are an indication that something is wrong.

The user or group is provided by a network database that is currently inaccessible.
A user or group was removed, but there are still files belonging to it.
The file is viewed in the wrong scope:

over a remote filesystem protocol such as NFS, the server and the client have different user or group databases, and the remote filesystem does not perform the remapping that would be necessary;
on a removable disk which was moved between systems that use different databases;
extracted from an archive created in a different scope;
in a virtual environment (which could be anything from chroot up) which uses different databases.

Note that in all of these cases except for the temporarily unavailable network database, the fact that you see a number instead of seeing the wrong name is down to luck. If a user ID has been removed and reassigned, the new user with this ID will have control over the files left over from the old user with this ID — as far as the OS is concerned, this is the same user. If a file is viewed in the wrong user scope, and the ID happens to be assigned to different user names in the two scopes, the you won't get any warning. So while seeing an unnamed user or group is a symptom that something is wrong, you cannot rely on the symptom appearing. Unnamed users and groups should be part of a filesystem audit, but they aren't the main focus.
Comment: Is there any reason why ids should get recycled in systems with low turnover?  If user "fred" with ID 57 leaves, why not simply rename the account to "reserved57" and never use ID 57 ever again?
Comment: @supercat Some admins do that. Some don't, either because they like to keep the system clean or because it doesn't scale — if you don't delete accounts, then eventually, the user database will be almost only closed accounts.
Comment: Some systems have much higher turnover than others, but I've seen account iDs reused even on systems which create less than a dozen accounts per year.  Unless a system will have over a billion different users in its lifetime, there should never be any need to create a new user ID that's less than the highest existing one, and "reserved" users could be deleted whenever some higher-numbered user exists.


Is it safe to eat pumpkin seeds with peel?

Question: I dried pumpkin seeds but now don't have the patience to peel them one by one. Could I just eat them with the skin? I suppose I could but they won't taste very good. Therefore, bonus question: in which form could pumpkin seeds with peel be used? So far I would try to blend them and put some in dough for bread.
Answer: We never peeled them growing up.
We'd coat them in some oil, roast them in the oven (stirring occasionally), then season them when they came out.
Comment: Roasted and salted unpealed ones are common in South Europe too. Northern of the Alps are often served at buffet for various salad composition, or on pumpkin soups or bread roll.