I can't see how free will exists in a universe that's only causal or random, can I be convinced otherwise?

Question: From what I've looked into on the topic of free will, I've found it difficult to see how it could exist in a universe of pure causality or randomness. However, I haven't fully abandoned the idea of free will as it may be possible in either a way I can't perceive or there's possibly some other option in how the universe works other than causality or randomness. I want to make sure I'm not being close minded and instantly accepting the non-existence of free will. So are there any arguments that may give me a better understanding of how free will could exist without being incoherent?
Comment: Possible duplicate of [How is free-will formally defined as distinct from determinism, randomness and determinism-randomness hybrid to support moral responsibility?](https://philosophy.stackexchange.com/questions/52088/how-is-free-will-formally-defined-as-distinct-from-determinism-randomness-and-d)
Comment: The issue of [Free will](https://plato.stanford.edu/entries/freewill/) is complex... Maybe we do not live in a "universe of pure causality or randomness".
Comment: Seems like you saying, "By definition, free will can't be causal, or random...so I can't see how free will exists in a universe that is only causal or only random."  Everything depends on your definition of "free will".
Comment: I made some minor edits.  You may roll them back or further edit if you find them inappropriate. Mark Balaguer's *Free Will* discusses the possibility of libertarian and physicalist free will. There's a chat room open on the general topic of free will determinism and fatalism if you want to discuss it further. https://chat.stackexchange.com/rooms/76868/free-will-omnipotence-determinism  Welcome to this SE!
Comment: @Chelonian the problem is i cant see random choice or determined choices being free at all. Kind of what I'm trying to ask here is if there is a possible option beyond determinism and randomness. some way of operation in the universe either imperceptible or unknown as of now. What I'm looking for is any possible way to make free will a coherent concept.
Comment: @JacksonFox - Freewill is not a coherent concept in any common formulation. A popular view would be that metaphysically (ultimately) speaking there is no such thing, but that for all practical purposes in life there is such a thing. Thus metaphysics is respected and also our undeniable human experience. This dual-aspect approach is found in mysticism and most notably in Buddhism.
Comment: @JacksonFox Well, then, that's a different question than the one you asked. You could ask that as its own question. But a preview answer is: Many people believe in a will that is "causa sui" (self-caused) and therefore neither random nor determined by external forces. It seems to me that it requires a belief in some kind of supernatural aspect.
Comment: What difference would it make if "free will" exists?  Something to do with being punished or rewarded in an after-life?
Answer: You write:

I haven't fully abandoned the idea of free will as it may be possible in either a way I can't perceive or there's possibly some other option in how the universe works other than causality or randomness. I want to make sure I'm not being close minded and instantly accepting the non-existence of free will. So are there any arguments that may give me a better understanding of how free will could exist without being incoherent?

There is another option - that the universe cannot be understood in terms of determinism nor randomness; however since these are the only two categories by which we can comprehend it, this option is necessarily incoherent, or better said unintelligible. It is a mystery to me why so many philosophers insist on coherency or intelligibility of the universe - such incredible vanity.
If you really want to make sure you are not being close minded then take a look down this unfashionable path.
Comment: Your claim that "these are the only two categories by which we can comprehend it" needs to be justified. An alternative to both might be something like agent causation with agents of all sorts acting each within their limitations. That these agents are limited allows us to make predictions on what is likely to happen. This also need not involve theism, but doesn't present an obstacle to theism either.
Comment: Does it really need to be justified? I would love to hear of an intelligible alternative to these two. If you come across one please let me know as soon as possible. How is agent causation, or a collection thereof, an intelligible alternative? if all agents are analyzable in terms of determinism or randomness, why would their aggregation fail to be? on the other hand if any of them cannot be understood in terms of determinism and randomness but can nevertheless be explained intelligibly then please provide that explanation.
Comment: as you read through piles of text on this subject, the product of thousands of years of futile arguments, keep an open eye for arguments which are nothing more than jargon heavy and magical hand waving - https://youtu.be/vdnA-ESWcPs?t=1m56s
Comment: Well, it's not hard to assume the incomputability of the universe, so, I don't see the incoherence.
Answer: A resource that is helping me to answer your question is The Problem of Free Will, a major aspect of the website Information Philosopher. A variety of well thought out positions of philosophers and scientists concerning the classic problem of free will are presented in depth. The problem is defined thus, "to reconcile an element of freedom with the apparent determinism in a world of causes and effects, a world of events in a great causal chain."
There is wealth of material to dive into, hundreds of pages at least. The website is the work of Bob Doyle, an Associate in the Astronomy Department, Harvard University. He has an impressive body of work, including with Daniel Dennet.
One article of interest to me regards a seemingly incoherent position attributed to determinism, namely that experimental results in a particular theory are pre-determined! The free choice position is then made plausible. This point is made in an exposition of work by John Conway, the Princeton mathematician who gave us The Game of Life and Surreal numbers, and Simon Kochen, also of Princeton, coauthor of the Kochen-Specker Theorem. Kochen's theorem, a variation of Bell's Theorem, "puts limits on 'hidden variables' that could make quantum mechanics a deterministic theory."
Conway and Kochen have developed what they refer to as The Free Will Theorem based on axioms derived from quantum physics and the theory of relativity. The exposition is rather long and somewhat technical. The author of the article sums up their theorems (there is also a Strong Free Will Theorem) by saying that "Another way of looking at their work is to say that Conway and Kochen are trying to close a 'loophole' in the Bell inequality tests. We might call this loophole the 'determinism loophole' or better the 'pre-determinism loophole.' If determinism is true, then all the experimental tests might have been pre-determined to show that quantum mechanics is correct, and indeterminism exists, where the real underlying nature of the universe is deterministic."
The author then goes on to highlight the incredible idea that all the experimental tests were pre-determined by saying "This is beyond belief, but not beyond the hope and dreams of many thinkers, especially mathematical physicists, who hope to show that information is conserved, and that Einstein, Schrödinger, de Broglie, Planck, and friends were right, Heisenberg and Bohr were wrong."
Bohr's wrongness is in reference to free choice, which he  wrote about in the essay, 'The Causality Problem in Atomic Physics.' Lengthy quotes from the essay are given. The article's author states,  "Bohr again emphasizes the 'free choice' of an experimental procedure in his solution to the EPR paradox.
Answer: It depends on how far randomness goes. You could still make choices/ decisions and form intentions in a world in which everything else but yourself were random but any free will you had would be nugatory : in a random world any choice/ decision you made or intention you acted on would have totally unpredictable consequences. You might decide to walk into a shop and find yourself, not in the shop but at the top of Mount Everest. A deliberately surreal example which makes a valid point, namely that free will, to be functional, needs at least a moderately stable and regular world in which consequences can be foreseen or at any rate calculated much or most of the time with reasonable probability. This would not be the case in a random world.
But now, if randomness penetrates the agent themselves, then I don't think free will is possible. If one's character or personality were to change randomly, and whatever one's character or personality one's choices/ decisions were random in relation to it, and whatever one's choices/ decisions one's intentions (the next stage towards action) were random in relation to them, this situation is not one I can understand as that of an agent with free will.
In the limiting case, of course, a random world might coincide in one of its possible states with the actual world and it might randomly remain in that state. If so, the conditions above which negate free will would not apply. This leaves open, of course, whether we have free will in the actual world : a topic I am glad not to have to address, at least here.
Comment: _Will_ (in "free will") is a reflective supplement (I decided myself; I have to decide) which adds nothing active to the spontaneous decider, only the knowledge (ie emergent circumstance). If it were my _will_ what's to decide it would have to appear in the form of caprice or stubbornness (in order to linger myself / endure the changing world), which means the will must be founded by Being (as some constant, base). That is, the wish (which the will is attached to as its engine) needs to be. This immediately will make the wish obsolete, since what already _is_ cannot be wanted anymore.
Answer: Mark Balaguer in Free Will shows how someone who accepts a physicalist view of the world can still be a libertarian with respect to free will. Balaguer references Sam Harris's Free Will. His book could be viewed by a reader as a response to Harris.
Balaguer rejects free will as something he doesn't even want except for those few times perhaps every hour where the indeterminacy, that is, randomness, in our brains allows him to make choices that are not determined by any prior event.  Those few times are all one needs to claim we do have free will.
From Balaguer's perspective once one philosophically accepts physicalism the question of whether we have free will or not is a scientific question. However, that question is unresolved today and it will unlikely be resolved in our lifetimes.
Robert Kane's "Free Will: New Foundations for an Ancient Problem" Proceedings of the British Academy, 1962 (reprinted in Free Will Hackett Readings in Philosophy, 2009) takes a similar view.

Although the above arguments should give a physicalist pause before asserting that we do not have free will it does not address the issue from a broader perspective where a different paradigm about who we are and what the world is is preferred.
Such a different paradigm need not be a theistic paradigm although a theistic paradigm such as the one underlying Alvin Plantinga's "Free Will Defense" would be one such paradigm insisting on our free will to avoid the logical problem of evil. The atheistic paradigm represented by Thomas Nagel's article "Panpsychism" (in Mortal Questions, 1979) would also challenge the physicalist view of the world.
Is there any reason to even consider a different paradigm than physicalism? With the introduction of the dual and opposing explanatory ideas of determinism and randomness based on mathematically modeled, and hence deterministic, classical science and indeterministic quantum physics it makes one wonder if there isn't something simpler underlying both of these principles. That simpler underlying principle may impact our view of free will.

Given the above there are at least two ways to motivate one to question the belief that we lack free will.
First, there is the realization that given physicalism the scientific question of whether we have free will or not has not been resolved and will unlikely be resolved in our lifetimes. It is premature to say we do not have free will given physicalism.
Second, there are other perspectives besides physicalism that might be closer to the truth about who we are and what our world is.
One might add to those two a third perspective.  If we deny our free will we are accepting a particular rationalist description of the world and rejecting the evidence of our own experience that we actually do have free will. Is our free will an illusion or is the belief that we do not have free will a rationalist delusion? Are we rationalists or empiricists?
Comment: Thank you! I hadn't really read into Mark Balaguer but this info helps clears things up about how free will can exist, same with Robert Kane. However, when you say other perspectives besides physicalism, what other ideas are there that would help clarify the idea of free will and make it coherent in a non physicalist world?
Comment: @JacksonFox I don't know what all the other perspectives are besides physicalism between the theistic Christian view Plantinga presents and the atheistic panpsychist view Nagel presents. However, I try to be open to all these perspectives that I become aware of as well as wary of them. One way to look at free will is to think of it in terms of agency. Free will allows agent causation. Causal determinism only allows event causation. Also it helps to ask how each non-physicalist perspective views who we are as human beings. Each view should fit our own understand of ourselves.
Answer: I tend to agree. But, free will can exist subjectively, even if not objectively. What can be computed in theory greatly exceeds what can be done so practically, even within the limits of the resources of the universe. We need heuristics, which give us an apparently supervening explanatory layer of minds.
Subjectivism points out that our own minds must be our most fundamental experience, preceding all other experiences. Althougb we collaborate with language and science to find correlating evidence for things from different sources, this whole structure is neccessarily built on top of minds percieving things. So for instance, time may turn out to be an artifact for us to organise our experiences, rather than truly how things are. Our futures may exist unknowable by us. This could have real consequences on how they universe turns out to operate.
Substance dualism acknowledge that mental phenomena and material phenomena are different aspects of the same substance. Science has historically come down on the side of a material substance. Buddhism takes the side of a fundamental mind substance. Quantum mechanics is increasingly coming down more between the two, defining the substance as information https://en.m.wikipedia.org/wiki/Digital_physics#Wheeler's_"it_from_bit" This is different to seeing reality as either psychological or material, it describes it instead as events, and interactions. This is a space in which what seems to be unique about the resukts of natural selection and the character of minds -their impacts on feedback between niche and adaptation- can be integrated with atoms and the void.


According to catholicism, what is the signification of burning incense during the liturgy?

Question: What is the signification of burning incense during mass and other liturgical functions?
Answer: One commentary on this survives from a time when the Roman Catholic Church was united with the eastern Sees.  It is from a work in Greek by Germanus I, Patriarch of Constantinople from 715 to 730, entitled Ecclesiastical History and Mystical Contemplation, available in a dual Greek-English format from St. Vladimir Seminary Press (Germanus is regarded as a Saint within both the Eastern Orthodox and Roman Catholic Churches).
Although he is explaining the eastern, Byzantine liturgical rite and not the western, I think that his explanation would also be accepted within the context of the Roman Catholic Mass:

The censer demonstrates the humanity of Christ, and the fire His
  divinity.  The sweet-smelling smoke reveals the fragrance of the Holy
  Spirit which precedes.  For the censer denotes sweet joy.
Again, the interior of the censer is understood as the [sanctified]
  womb of the [holy] virgin [and Theotokos] who bore the divine coal,
  Christ, in whom the whole fulness of deity dwells bodily (Col. 2:9).
  All together, therefore, give forth the sweet-smelling fragrance.  Or
  again, the interior of the censer points to the font of holy baptism,
  taking into itself the coal of divine fire, the sweetness of the
  operation of the Holy Spirit, which is the adoption of divine grace
  through faith, and exuding a good odor.
Answer: Incense has been used in the Church for centuries.

We do not know exactly when the use of incense was introduced into our Mass or other liturgical rites. At the time of the early Church, the Jews continued to use incense in their own Temple rituals, so it would be safe to conclude that the Christians would have adapted its usage for their own rituals. - WHY IS INCENSE USED DURING MASS?

As for what is the signification of burning incense, this pleasant sweet aroma of the incense signifies our prayers being taken up into heaven and into the presence of God.

Incense is a very ancient symbol of prayer and offering. Archeological discoveries have suggested that humans may have been using incense for religious purposes as far back as twenty-five thousand years ago. The ancient Hebrew people continuously offered incense to God in the Temple as a symbol of their prayers. In the Psalms, the hymns of ancient Israel, the poet sings, "Let my prayer be set forth in your sight as incense; the lifting up of my hands as the evening sacrifice." (Psalm 141:2). The incense smoke that silently rises to heaven is a symbol of our prayers carried heavenward to God.
The Book of Revelations enriches this imagery as an angel "who had a golden censor, who came and stood at the altar. A large quantity of incense was given to him to offer with the prayers of all the saints on the golden altar that stood in front of the throne; and so from the angel's hand the smoke of the incense went up in the presence of God and with it the prayers of the saints." (Revelations 8:3,4). Using the imagery of the worship of God in Heaven itself, the Church uses incense to worship God here on earth where our prayers rise and are joined with the prayers of the whole company of heaven assembled around God's throne. - Holy Smoke! Why do we burn incense?


What instruments are used to indicate aircraft attitude in acrobatic airplanes?

Question: As aerobatic airplanes don't use gyroscopic instruments such as attitude indicators, what instruments are used to indicate the aircraft's attitude in flight?
Comment: They aren't doing aerobatics IFR, so the best way to determine attitude is to look out the window, some have additional decides on their wingtips to align the horizon.
Comment: One way is talked about [here](https://aviation.stackexchange.com/q/35163/8730)
Answer: The basics:  Acro airplanes don't have attitude indicators because they don't need them.  The airplanes are certified at Day/Night VFR flight only and gyroscopic instruments are not required equipment here, not to mention can be precessed and damaged by aerobatic flight.
The only attitude instruments needed here is the horizon itself and the pilot's Mk I eyeballs to see it.
Sometimes pilots make use of aerobatic sights mounted on the wingtips; these look something like eight spoke cowboy spurs or a 45° right triangle frame and are used to fly certain reference lines during aerobatic flight.
Some acro aircraft do make use of glass cockpits and solid state Attitiude, Heading, and Reference Systems (AHARS) as a safety backup on cross country flights, but they are not used during aerobatic routines.
Comment: Aeroobatic aeroplanes *might* have attitude indicators, or be certified for IFR flight, I think you may be thinking of competition aircraft, however there are a lot of aerobatic capable aircraft that are used just like normal GA aircraft, like the Cessna 150/152 Aerobat, or the American Champion Citabria, Decathlon, and Super Decathlon, mechanical attitude indicators can be equipped with caging mechanisms during acrobatic flight.
Comment: I'm aware of very few aerobatic aircraft equipled with attitude indicators or gyro instruments, primarily because the airplanes don't need them for day/night VFR flight.  An aerobat might but the Citabria/Decathalon line does not use gyro instruments.


Can I stream video from iPhone to VLC?

Question: Is there a solution/app available that will allow me to take video from iPhone/iPad camera and live-stream it to a VLC player running somewhere else in my WiFi network?
Searching around for iPhone RTP/RTSP encoders isn't coming up with much.
Answer: You could try the Airplay functionality for iPhone ( though I'm not sure if it is available on all iPhone devices, but it is on the 4S ).
Then try and find an Airplay plugin for VLC.
It's already possible for Windows Media Player so VLC can probably do it too ( and be better at it, because you know, it's VLC ).
I haven't tested it myself, but it's probably worth trying out.

Can I stream video from iPhone to VLC?


SQL/IIS (Classic ASP) Web Application Performance Optimization

Question: We have a Classic ASP web-application that we are hosting with a 3rd party hosting provider (Rackspace).  We have ~ 100 databases on a SQL server and around the same number of websites on a Web-Server (IIS).  Does anyone have any tips for optimizing performance.  We occasionally see memory and CPU spikes throughout the day.  We are setup with a simple SQL server and Web-server pair.
Answer: On the SQL side of things, it might be a good idea to use SQL Profiler to identify any of your queries or stored procedures that are taking a long time to run. If you can identify any real problems here it can help speed up your application.
Keep in mind the Profiler tool often requires a lot of filtering to get the correct information. It is nice in the fact that you can record the start times of the queries being run and try to match them up with your CPU spike times.
Comment: Agreed.  A simple "show me all queries taking over 200ms to run" filter will uncover a lot of low-hanging fruit.  Every application has a few of these long-running queries that can be tuned down to a few milliseconds once you know about them.
Answer: That's not a simple question and doesn't have a simple answer. Entire books have been written on the subject of performance optimisation.
Maybe try starting with these articles which go into (in the first part) finding the performance problems.
http://www.simple-talk.com/sql/performance/finding-the-causes-of-poor-performance-in-sql-server,-part-1/
http://www.simple-talk.com/sql/performance/finding-the-causes-of-poor-performance-in-sql-server,-part-2/
I can also suggest a book. "SQL 2008 Performance tuning distilled" by Grant Fritchey and Sajal Dam.
If you can find the worst performing of the queries, post them here or on a good SQL forum and someone will definitely help you. As it is, the question's way too broad to have a simple answer.
Answer: I suspect you're going to need to do some profiling. At a gross level, you need to know where the bottlenecks are, so typical Windows performance monitoring guidelines apply. Chart gross performance of CPU (% utilization, % user mode vs kernel mode, context switches), disk (queue length, % disk time), and memory (page faults / sec, working set sizes). You'll want to start narrowing it down to which processes (IIS WAM, SQL Server, etc) are giving you grief.
Like the other posters said-- if it's the SQL queries you're running, then it's probably a database optimization problem. Don't overlook the possibility that your scripts, however, are executing silly queries (SELECT * and filtering the results in the script, etc) that are causing anomalous database load.
If do you get down into individual scripts (i.e. you find that the bottleneck points to IIS / WAM processes), then have a look at this Stackoverflow question: https://stackoverflow.com/questions/398028/performance-testing-for-classic-asp-pages  There's a code snippet in there that is a basic execution timer. At the risk of impacting performance further, but in an effort to get more visibility, you could also consider logging the parameters passed into and execution times of your scripts into the database. Looking for outliers in that data might help you find edge conditions in your scripts. Ideally, you want to design with profiling in mind from the start, and retrofitting can be tough.


Where is a good place to find writing prompts?

Question: I love using writing prompts to come up with story ideas. I'm looking for good sites that have a lot of good writing prompts. One that updates fairly often would be best. :)
Comment: I'm going to start a bounty for this.  What I will be looking for in awarding the bounty is an answer that lists not only *what* the prompt is (where you can find it and the genre), but *why* it is helpful.  Specific examples of what you've learned, how the prompt has become part of a piece, etc. would be helpful.
Comment: Please note that this question has been retained for historical reasons, and shouldn't be considered a good example of an on-topic question for this site.
Comment: Related: [Resource for generic plot hooks?](http://writers.stackexchange.com/questions/7052/)
Answer: I know Writing Excuses has a writing prompt at end of each weekly show. Usually they are related to the topic of the show as well.
Answer: I haven't read it myself, but I think this book, The 3 A.M. Epiphany by Brian Kitely, sounds like exactly what you're looking for. It's got very nice reviews - both in terms of score, and the actual description. Here's the first one that sounded like a great match for your question:

The exercises also have an additional dimension to them that most don't. Each one is
  carefully constructed to help you explore a certain aspect of your writing. These aren't
  meant to be "merely" inspirational--they're designed to teach technique, as well, without
  reading like a dry instructional book.
There are types of exercises in here I really haven't seen anywhere else, particularly in
  the sections on "Internal Structure" and "Exercises for Stories in Progress", and I think
  you'll find them inspiring in ways that other books aren't. They'll make you think, work
  and write in whole new directions.

It sounds so tempting, I'm inclined to get a copy myself. :)
Comment: I own a copy. It is definitely pretty helpful.
Comment: Oh, good :) I ordered one a couple weeks back.
Answer: I love The Writer's Book of Matches for fiction writing prompts.
Answer: Not a writing prompt in a traditional sense, but this has worked for me: improv comedy classes.  Every time you perform a scene, you're creating a completely new story on the fly.  It's a great way to generate ideas.  The story grows organically, and you'll get unexpected (i.e. creative) results.
It's a fun way to get new ideas for writing.
Answer: This article describes an interesting system for coming up with infinite writing prompts through Wikipedia.
Answer: Type Trigger
is rather fun - you get a very short prompt (one to three words) and then write up to three hundred words on that prompt. There's a new prompt every hour. It's an energetic little writing exercise.
Answer: http://www.seventhsanctum.com/generate.php?Genname=writechallenge
Updated every time you click
Answer: Writing Prompt Websites
This is basically a link to an existing list elsewhere. That's because I think the most important aspects of writing prompts are:

A variety of compelling topics
A sense of community for peer support

The definition of each of these will differ for anyone asking this question, so the best answer is a list with diverse topics and diverse peers.
Answer: This, I think, is a writing prompt tool unlike any other.  Whereas most prompts just start you off, this one can assist you with the continuation of your story.
It provides multiple ways to get a prompt depending on your mood or goal.  Whether you want a complete scenario, a starting scene, a goal, or a character, you just click a button.
I recommend reading some of the example stories to get an idea of how people are using it here:
Actual Play Reports
Here is the home page that has some more information on it: http://www.rpgsolo.com
If you get lost there is great documentation in the forum.
Answer: Instead of finding a source of explicit and structured prompts, I opt to look for randomized inspiration.  Every day or two, I do the following:

http://www.flickr.com/explore - I browse until I find 3-5 images that strike a chord of interest in me (for any reason).
http://live.lmgtfy.com/ - I watch these live search terms with a text editor open and simply choose 5-10 individual words that pop up (again, whatever grabs me that day), writing them down.

Almost without fail, when I smash the words up against the images, I get struck with a nugget of a "wouldn't that be interesting..." kind of idea, then I write anywhere from 200-500 words on the topic.  These short exercises are always brief and not well fleshed out, and they are often terrible.  I write until the core of the idea is laid out, then I stop and file them into a folder with all the rest.
But the point isn't to get a winner every time, the point is that much later, when I'm ready to begin writing a new story, I don't need to go looking for prompts or ideas... I have a collection of dozens (or more) ideas that I've already had.  All I have to do is browse through them and I always find at least a few that inspire me to explore them further.


Why is the RDY signal on floppy disk drives disabled?

Question: While look at some 3.5" floppy disk drives I have, I noticed they have a little resistor missing next to RDY and, looking it up online, I find some instructions for adding a resistor there to enable it. What is it and why would I want to enable it (or why is it not already enabled)?
Answer: Ready was traditionally the signal that went active after the motor had been turned on and two index holes had passed. So it primarily indicates that a disk is present, and also implies that the drive has had time fully to accelerate.
IBM redefined that pin to indicate disk change — it goes inactive when a disk is ejected and active again when the head steps a track.
I would dare imagine the resistor allows you either to pick a behaviour, or to intermingle them; a combination of both tests works on some machines.
Comment: Oh well, far too slow. But I'll leave this here as I think it adds detail.
Comment: Thanks, that is indeed useful! I was wondering whether a drive with the ready signal enabled would still work in a PC...
Comment: If memory serves, the drive's 'ready' signal isn't used directly by an 8272/765, other than to expose it in response to the sense drive status command. So it'd be up to the operating system. So I have no idea.
Comment: Why was it necessary to have a disk-change switch?  It's generally not possible to swap disks without the write-protect indicator going from "beam is blocked" to "beam is not blocked" (which is how the Commodore drives like the 1541 detect disk swaps).  Why would that not be sufficient?
Answer: PCs don't use the ready signal, and since most floppy drives ended up used in PCs, manufacturers could save a little by ignoring it.
You'll need it if you want to use the drive in some other systems (notably the Amiga, the Amstrad CPC and PCW). It must be active low when a disk is in the drive, and importantly, it must switch to high and back when the disk is replaced.
Some drives have jumpers which can be used to enable the ready signal; others like yours require modifications.
Answer: The Ready signal is part of the original Shugart floppy bus specification, but the IBM PC and compatibles used a different pinout. (One key benefit was to eliminate the need to configure floppy drive numbers with jumpers, by configuring them all the same at the factory, and using a twist in the cable to distinguish between two floppy drives.)
PCs expect to receive a different signal on pin 34, to indicate whether the disk is still in the drive or if it's been ejected and swapped (Disk Change). Shugart-compatible systems such as Amiga, Acorn, or Amstrad machines still expected to receive a Ready signal on this pin.
Rather than design different floppy drive circuit boards for each market, it would make economic sense to have one circuit board which could be configured to operate to either standard. The addition (or omission) of this resistor is how the configuration would be selected when the board was assembled, and how you can modify the board yourself later if you wish.
Comment: The additional information on this history of this is good, but the answer could be improved by explaining exactly what the "READY" signal is in that spec, linking to the spec (there's a manual on archive.org), and perhaps explaining why and how IBM's changes changed the pinout, and where the pinout changed (on the drives themselves?).


Does TFS Build have something like a Jenkinsfile?

Question: I've seen some custom settings files used in combination with TFS build, but nothing native.  Does Team Foundation Server or Visual Studio Team Services have a Jenkinsfile-like, declarative method for defining a build process?
Comment: Do you have any specific requirements for TFS Build? That would probably help any answer to actually help you solve your problem—what I think is like a Jenkinsfile might be different to what you're expecting, so a few constraints would be useful to know.
Comment: I'm generally looking to provide the ability to source-control the build process, in the same way that a Jenkinsfile does.  TFS build pipelines are very opinionated, and fine-grained access to them doesn't look possible.
Answer: The strict answer is no, in that there is no direct equivalent to a Jenkinsfile. However, there are Build Process Templates and you can use the Psake Build Automation tool in combination with templates to reduce the barriers to entry for creating a new build, test and deployment build definitions.
It is nowhere near as fluid as Jenkins' Pipelines as Code, AppVeyor's appveyor.yml, CircleCI's circleci.yml and Travis' .travis.yml.  There is a wealth of information on the ALM Rangers Library of tooling and guidance solutions.
Answer: Visual Studio Team Services has a YAML Build feature in public preview that allows you to store your build definitions as source controlled files.


Xbox 360 green light turns on but it does not work or boot up

Question: When I turn on my xbox 360 I can hear the fan working and The green light in the middle turns on. I am not able to connect a controller. When I turn on my tv nothing shows up. My xbox had been working perfectly fine a couple of minutes ago. When I tried to turn it on again this happened. The adapter light is orange when the xbox is off and when I turn the Xbox on it turns green. I am able to open and close the disc tray to insert a game disk but nothing happens. Does any one know what the problem is?
Comment: I'd suggest checking the HDMI cable and input on your TV (assuming you use HDMI to connect the 360 to your TV).  Mine won't connect controllers or finish booting without the TV being connected and the input properly set.
Comment: [If it is turning itself off after a while this may be helpful](http://gaming.stackexchange.com/q/30947/42984)
Answer: I guess you have to get yourself a new xbox or send it to Microsoft if you still have warranty (if you have something like x360key, obivously remove it first). It has nothing to do with the HDMI cable (or any other cable) since you can't connect an controller (you could try another controller).
Comment: I would agree, but if you've already taken it apart to use an x360key you probably have voided the warranty :/ which would suck and the cost to repair is the cost of a 360 anymore. If you've done this option, you're out of luck on a free repair.
Answer: Does the Xbox do the spinning ring of light on boot? If it does, do you have other screen cables? Did you change screen settings recently? If you have recently changed resolution to a higher pixel ratio (1080p from 720p or 480p) you might need to connect a pair of cables that switch from HDTV to TV and use the TV option for the moment, this will force the 360 to rewrite the config of the resolution and use 480p for standard CRT TVs. Chances are that if you can't get any picture at all form either your HDMI or Standard screen cables that the video component is shot and you would need to contact xbox support. It's rare but I've seen it happen and falls under warranty if the xbox is still in the three to four year warranty.
Answer: There is a lot of things that can be causing this. Is your connection cable in right? Is the connections on the Xbox on right? Are you on the right TV input? If using three cables, are the colors on the correct positions? Is the HDMI cable broken? Is the ring around the xbox red? Check them out before submitting for a new Xbox.
Answer: Change composite cables (red white yellow) or hdmi connecting to tv. That will fix it because your xbox cables are damaged.
Comment: Why will this fix it?  Add in some more information about that, please.
Comment: How do you know their cables are damaged?  Have you encountered this before?  Is there something in what the asker has said that makes you believe that this is the problem?


feature selection techniques

Question: Is it always a good idea to remove features that have high mutual information with each other and to remove features that have very low mutual information with the target variable? Why or why not?
Comment: One thing not mentioned here why redundant features are removed is interpretability. You cannot interpret the coefficients of a linear regression if you have correlated covariates. But the prediction can be good nevertheless.
Answer: Doing that is a very good idea. The problem is that doing that is very hard.
Feature selection is a NP-complete problem.
The practical meaning as that we don't know any fast algorithm that can select only the needed feature.
In the other direction, omitting features that don't have mutual information (MI) with the concept might cause you to throw the features you need most.
There are cases in which a single feature is useless but given more features it becomes important.
Consider a concept which is the XOR of some features. Given all the features, the concept is totally predictable. Given one of them, you have 0 MI.
A more real life example is of age at death. Birth date and death date give you the age. One of them will have very low correlation (due to increase in life expectancy).
In practice, omitting features with low MI is OK. Many learning algorithms are using MI so they won't be able to use the omitted variables anyway.
As for the selection itself, there are many algorithms, usually heuristics or approximation algorithm that are quite handy.
Comment: can you please give an example of when removing a redundant feature produces a classifier that has less performance power?
Comment: If in redundant you mean exactly the same, than you can safely remove them. If they are different, consider a case of n features with high MI among them and low MI with the concept. If you'll remove them, you'll lose the MI with the concept. For example, let say there is a basic feature x and all the other are x with probability p and the concept with probability (1-p), independently.
Answer: The fact that a feature is redundant in the presence of another one, or is not informative enough to describe the target variable, is not necessarily a sign of that feature not being useful.
Indeed, it may be the case that such feature may be extremely informative when combined with another one, in spite of not being very useful when considered in isolation.
Therefore, when applying feature selection methods, you should also consider combinations of features.
However, and as pointed out by another answer to this question, finding the best combination of features is a NP-complete problem. Therefore, applying feature selection to individual features may be a good approximation. However, I'd rather apply a greedy approach (see for instance https://studentnet.cs.manchester.ac.uk/pgt/COMP61011/goodProjects/Shardlow.pdf for more information about the topic.)
EDIT to answer OP's comment:
a) The table below displays an extreme example of a feature that by itself is very informative, but in combination with others is totally redundant (feature_2). This is a regression problem in which we are trying to build a model to predict the "output" variable from "feature_1" and "feature_2".
<code>| feature_1 | feature_2 | output |
|-----------|-----------|--------|
|         1 |         1 |    0.1 |
|         2 |         2 |    0.2 |
|         3 |         3 |    0.3 |
|         4 |         4 |    0.4 |
|         5 |         5 |    0.5 |
|         6 |         6 |    0.6 |
</code>
b) The example below shows an extreme example of a feature that may not be very informative by itself, but that is very informative together with another one (feature_2).
<code>| feature_1 | feature_2 | output |
|-----------|-----------|--------|
|         1 |         1 |    0.1 |
|         2 |         2 |   0.25 |
|         3 |         1 |    0.3 |
|         4 |         2 |   0.45 |
|         5 |         1 |    0.5 |
|         6 |         2 |   0.65 |
</code>
Comment: can you please give counter examples for both cases i stated? I cant seem to understand this intuitively.
Comment: Edited my answer to include some simple examples.
Answer: As with many things, it depends. The specifics of the relationship of your variables to the domain they describe will dictate, and even then relationships may not be intuitive. Seemingly disparate features can have a significant effect when combined in what is known as feature extraction.
Automated feature engineering techniques can help you decide what features are significant if you have the time and resources available, particularly when it comes to testing the impact of combined features.  Additionally, some methods have the benefit of embedded feature selection, wherein the algorithm itself tends to diminish the effect of insignificant variables, e.g.: lasso regression, regularized decision trees, random forests, etc.
Here's a nice primer: http://machinelearningmastery.com/an-introduction-to-feature-selection/
Comment: what exactly do you mean when you say relationships may not be intuitive? Can you please give me an example?
Comment: My comment about intuitiveness was with respect to _a priori_ feature selection, i.e.: when not using automated or embedded techniques.  In some domains an expert may make an intuitive guess about what features are relevant (e.g.: temperature and ice cream sales), whereas in other domains such intuition is not possible (e.g.: gene expression microarrays; sports telemetry data for specific physical activities).  There is, of course, a wide variety of possible cases in between.
Comment: But, to wrap it back around to your question, it is a good idea to reduce features in order to reduce training time and reduce the chance of overfitting and bias, but only when not using embedded feature selection techniques or after performing an automated sweep to verify significance. [Another short article](http://machinelearningmastery.com/feature-selection-to-improve-accuracy-and-decrease-training-time/)

feature selection techniques


What happens to a spent Bitcoin that was earned from a chain replaced by a longer chain?

Question: Let's say miner Moe mines a block taht is accepted by the network.  Moe presumably receives some Bitcoins in his wallet for this.  So let's say Moe "spends" that Bitcoin by buying some anti-poking goggles from Curly, even though his newly mined block is at the top of the chain and has no blocks on top of it.  Curly sends the goggles to Moe via FedEx.  Then another miner Larry mines a longer block and that replaces the original one Moe mined.  So now Larry has some Bitcoins.  So does the transaction between Moe and Curly disappear and Curly is left without a pair of goggles and with no Bitcoin?
Answer: Yes, Moe's transactions (both the coin creation one and the payment transaction) become invalid if Larry mines a conflicting blockchain that has more work (almost the same as longest, but not quite) than Moe's blockchain. So Curly would be without payment and Moe would have gotten himself a free pair of goggles.
Now if Moe and Larry were the same person this would be a Finney attack where Moe/Larry are intentionally defrauding Curly.
Of course there are built in safeguards to protect against this. Firstly, Moe cannot spend newly mined Bitcoins until 100 blocks have been mined on top of his block. But even if he did wait 100 blocks before transacting, Curly could still be defrauded.
The solution to this is for Curly to wait for the payment transaction to get a few confirmations. By waiting for confirmations, the amount of hashrate that Larry would need in order to change the blockchain to not include Moe's transaction greatly increases. After a few blocks, it is basically infeasible and thus it can be said that the transaction is permanent and cannot disappear.
Comment: "But even if he did wait 100 blocks before transacting, Curly could still be defrauded." -- yes, but that would just be a regular double spend attempt.  A reorganization of 100 blocks is unreasonable.  After that much POW you can be assured that the block that mined the coins will stay in the chain.
Comment: "Firstly, Moe cannot spend newly mined Bitcoins until 100 blocks have been mined on top of his block" -- what exactly prevents this?  If Moe has hte Bitcoin adn Curly chooses to accept it (after being poorly advised not to wait for 100 blocks), what safeguard is there?
Comment: It is a consensus rule that prevents it. The transaction will be invalid. I suppose it doesn't matter if Curly accepts it even though it is unconfirmed.
Comment: But in my question Curly has accepted the Bitcoin before Larry has mined a longer block.  Or can this siutation never happen, since you mention Moe cannot spend newly mined Bitcoins until 100 blocks have been mined (which I'm guessing is part of the Bitcoin software)?
Comment: This situation is possible but easily avoidable.
Comment: Ok, then could you explain your comment "Firstly, Moe cannot spend newly mined Bitcoins until 100 blocks".  If my situation is possible it sounds like Moe could spend his Bitcoins immediately as long as there are a few suckers out there.
Comment: I misread your question. I thought Moe had mined a block containing that spend.


Create a PDF with a custom page size? (Mavericks)

Question: I'm trying to create a PDF with a custom page size.  Basically, I'm converting a set of JPEGs which are exactly 5:4 dimensions into a single PDF, so I wanted to set the paper size to 8x10, so as not to have "letterbox-type" borders on the top and bottom of the PDF pages. The purpose is for viewing on-screen, not for printing, and these are personal documents which I am not sharing, so there is no need to worry about printability.
I'm using a consumer-grade HP LaserJet printer (P1102W), whose driver apparently "does not support" custom paper sizes. This is evidenced by the fact that I am unable to choose the option to "manage custom sizes" in the paper size list - it is grayed out.
Researching around the Internet seems to reveal that only certain drivers actually will let you configure a custom page size. To experiment, in TextEdit (which does have the Page Setup option), I was able to configure a custom page size. However, Preview does not have a Page Setup option. I've also seen screenshots where certain HP drivers do enable this option, but I obviously don't know which ones, nor do I have the corresponding printer or driver on my system.
I tried installing a generic PostScript printer driver by entering a nonexistent IP into the network printer settings, but even then I was unable to set the custom page size.
Is there any solution I can use to accomplish this? Remember, the goal is to produce a PDF file with a custom page size to eliminate borders, and that PDF will never need to be printed. It seems silly to be limited by the printer driver when the goal is to produce a generic PDF...
Thanks!
EDIT: Ghostscript may be able to do this, but there's something wrong with either my installation or with the Ghostscript that Homebrew installed.
I created a PDF with Preview that had borders, and am now trying to use GS to change the page size. Here's the result:
<code>Mac-mini:~ fmillion$ gs -sDEVICE=pdfwrite -dDEVICEWIDTHPOINTS=612 -dDEVICEHEIGHTPOINTS=720 -dFIXEDMEDIA -c "<</PageOffset [0 36]>> setpagedevice" -o test1.pdf test.pdf
GPL Ghostscript 9.14 (2014-03-26)
Copyright (C) 2014 Artifex Software, Inc.  All rights reserved.
This software comes with NO WARRANTY: see the file PUBLIC for details.
**** Unable to open the initial device, quitting.
</code>
If I do not include the "-c" option along with its parameter, the operation succeeds, but I end up with a page with a half inch at the bottom and the top half inch of the page cut off. The idea of the PageOffset command was to shift the entire page down by 36 points, thus eliminating the bottom border.
I'm using the Ghostscript provided by Homebrew, simply installed with "brew install ghostscript".
Answer: It is possible to convert images to PDFs without 'placing them on a default page', so that each page will be whatever size the image is.
There is a collection of python scripts and Automator Actions here, which include one to batch convert images to PDF in that way.
https://github.com/benwiggy/PDFsuite
Answer: Though this question is quite old, I still had this same problem on High Sierra and found a solution that worked for me.
Since the custom size availability is apparently controlled by the printer drivers, and buying a new printer was out of the question for me, I simply downloaded "Additional Tools for Xcode 10" from Apple's developer site.
*Please note that you will need a developer id (which uses your apple id) to download these tools. You can get one for free at their site.
This toolkit contains an app called "Printer Simulator", Launch it and you will now see new printers available in Preview:

Select one and then you will have custom sizes available again.
Answer: One possibility would not care about the borders, and then crop the pages accordingly (for example in Acrobat; I am not sure whether Preview.app can crop, but worth a try).
Comment: Preview can crop jpeg images but it won't do anything to change the actual layout of a PDF document, i.e. it won't change the page sizes to match. Acrobat is an awfully expensive solution for a task this simple... I do have UNIX background, so is there maybe a way to do this with Ghostscript? (I have it installed with Homebrew but not very familiar with it...)
Comment: I am not sufficiently familiar with Ghostscript to decide whether it can either crop or force custom paper sizes; you'd have to try it out.
Answer: I had no problem at all setting a custom page size in preview using the Paper Size command in the print dialog. Just set the size and then use the pull down menu on the bottom left to open the PDF in Preview at the custom size.
Comment: Was this on Mavericks? This question is 4 years old so posting screenshots would improve your answer.


I can't change my screen resolution

Question: I am newer to Ubuntu. Recently I bought Intel® Core™ i3-2120 CPU @ 3.30GHz (Intel HD Graphics 2000 display) with Dell IN2030M monitor. I installed Ubuntu 12.04 LTS version. My problem is, I can't change my screen resolution >1024 because the monitor was not detected, it says Unknown. Help please.
Answer: You need to install at least the package mesa-utils.
On a console type:
sudo apt-get install mesa-utils
Logout and login
That will give you the basic graphic drivers, for advanced graphics you need to install Intel HD Graphics.
This has already been answered here and here

I can't change my screen resolution


How does Vision lift Thor's hammer in Avengers: Age of Ultron?

Question: In some scenes in Avengers: Age of Ultron Iron man, War Machine, and Captain America try to lift Thor's hammer but they end up failing. At some point Vision lifts it easily. How can Vision lift it?
Comment: Related: http://movies.stackexchange.com/q/33689/49.
Answer: Because he's worthy of it.
The fact that the Vision can lift the hammer, in contrast to all the other heroes (apart from Thor, of course) is an important clue to convey the Vision's actual spiritual purity and superiority. Remember that the Vision was created in a collaborative process by the Avengers, taking Tony's benevolent AI J.A.R.V.I.S, putting it into the pure mind gem (now cleaned of whatever evil spirit was in it that's now in Ultron), putting that into a perfect Vibranium-enhanced body and putting it to life by Thor's very powers.
To me the Vision seems to be the embodiment of the ancient ideal of a perfect mind in a perfect body, one that combines the advantages of a mechanical intelligence with the concerns and soul of an organic lifeform and brings compassion for his (undoubtedly inferior) human fellows, in contrast to his much less modest and unidentifiedly-spirited brother Ultron. He thus seems to be the ideal creation of a humanity that strives for posthuman evolution. One could say in his second try Tony Stark (with the help of an actual (demi)god and some magic alien artifacts, though) overcame his role as merely a "Modern Prometheus" and didn't just create sentient life, but a new god in itself.
And the fact that Vision is able to wield Mjölnir to me doesn't come from the fact that he is "just a machine", as Tony and Steve argue jokingly at the end, but from the fact that he is superior to us all not only in his body but even more so in his mind. And this I think is the attitude that Mjölnir is attracted to, as already shown in the first Thor movie and also in this one when Steve nearly achieves to lift it (which was not because he is the strongest, but because he is the noblest at heart). In fact, Tony's and Steve's theories about Vision being "only a machine" at the end even support the interpretation that this is not the case by the mere humorous way they are presented in. Of course their childish excuses are not the reason for why The Vision achieved what they couldn't. In fact his pickung up the hammer is a perfect and to the point illustration of Vision's superiority and immediately clarifies that to the viewers, a symbol that has been explicitly set up by the earlier scene (with the whole gang trying to pick up the hammer) for exactly that purpose. Or as the apparent expert on the intricacies of Mjölnir has to admit himself at the end:

Thor: He can wield the hammer, he can keep the Mind Stone. It's safe with the Vision and these days safe is in short supply.

And you wouldn't want to keep the Mind Stone lying around in an elevator. So yes, Vision does get the power of Mjölnir and Thor with everything connected, including the abstract notion of "being worthy". But what makes Vision so extraordinary as part of his "worthiness" and what makes it seem as if he doesn't get that power (i.e. without the nice special effects described in Dr R Dizzle's answer) is that he doesn't want it anyway. He doesn't strive for this power and he doesn't care to rule over Asgard, not because he can't as "a machine" or because he doesn't have a soul, but because his mind and motivations are above such "worldly" considerations. His light-handed and downplayed way to hand over the hammer to Thor and his easy ability to carry it in battle convey both his worthiness and his not caring about this at all. He is a god without a god-complex.
Answer: The inscription on Mjolnir reads;

"Whosoever holds this hammer, if he be worthy, shall possess the power of Thor."

We know from Thor, The Avengers, Thor: The Dark World and Avengers: Age of Ultron that only those judged worthy can lift Mjolnir. When judged worthy, the hammer gives the lifter the power of Thor. I elaborate on this in this answer, but the short of it is that those worthy of Mjolnir can not only lift Mjolnir, but they are also granted power by it.
Importantly, when we do see The Vision use Mjolnir rather than simply holding it (when he hits Ultron with it), we see that he hits no harder when 'wielding' Mjolnir than he would have anyway. The Vision is not granted the power of Thor, as the inscription on Mjolnir would suggest. This means that Mjolnir does not judge The Vision worthy, and as such can only be lifted by The Vision because he is not counted as a person from Mjolnir's perspective.
Additionally, when we see Thor regain his worthiness in Thor, his lifting of Mjolnir is accompanied by various special effects indicating him being 'powered up', none of which are present when The Vision lifts Mjolnir - because he isn't worthy, and has not been granted the power of Thor.
This means that when Tony and Steve are trying to comfort Thor at the end of Avengers: Age of Ultron, they are in fact correct - The Vision lifting Mjolnir makes him no more worthy than an elevator lifting it would, or as the Helicarrier in The Avengers or a coat hanger in Thor: The Dark World does.
In short, The Vision can only lift Mjolnir because his status as an android would seem to make him exempt from the rules.
Comment: *"none of which are present when The Vision lifts Mjolnir"* - As they aren't all the time Thor lifts the hammer apart from that moment.
Comment: @DrRDizzle But *Mjolnir* **doesn't** strip Thor of his powers (in *Thor*), *Odin* does, (while wielding Mjolnir, granted, but that is *Odin*'s magic, *not* the hammer's) he just leaves the backdoor of giving the ability to reactivate the powers again later open, should that become a need later in the plot (by basically storing the powers within Mjolnir).
Comment: This answer might also fit on [this highly related question](http://movies.stackexchange.com/q/33689/49) to a large degree.
Comment: @TomCody Because he never makes the transition from unworthy to worthy again. I see it like this - Mjolnir sees Thor as unworthy, and as such strips his powers and refuses to be lifted. When Thor is made worthy again, it grants his powers back (spectacularly) and allows itself to be lifted. From then on, Thor is worthy and doesn't need to be granted his powers again. I would expect anyone grabbing Mjolnir for the first time to be checked for worthiness - if worthy, grant powers (spectacularly), if not, don't move. Mjolnir shifted slightly for Steve because it couldn't make up it's mind.
Comment: @BMWurm of course, most if not all of Mjolnir's powers also come from Odin.
Answer: So far people have surmised that either...
A) The Vision's status as an android exploits a loophole in the rules regarding the wielding of Mjolnir, as set by Odin, because The Vision, as an artificial intelligence encased in a android body, isn't actually a person, but a machine.
Or,
B) that The Vision, being newly created and therefore not yet physically, mentally, spiritually, emotionally or morally compromised/corrupted in any way, and with him having been created by downloading Jarvis' benevolent artificial intelligence into an android brain/neural network designed by Ultron and powered by the Mind Stone, and that The Vision is therefore "worthy" of wielding Mjolnir.
I'd like to point out a couple of flaws in those theories...
As for the first theory, that The Vision isn't a person and can therefore lift Mjolnir in the same way as any elevator or heli-carrier or Quin-Jet would, it should be pointed out that The Vision didn't just lift the hammer - he threw it, caught it, flipped it, hit Ultron with it, etc.  He, in effect, "wielded it".  It should also be noted that Odin wouldn't be at all unfamiliar with androids or artificial intelligence - but I don't believe The Destroyer can lift Mjolnir either.
As for the second theory, that Mjolnir considers The Vision to be worthy of wielding it (and ruling Asgard too - let's not forget that!), I would point out that there was no "power-up" when The Vision first picked up the hammer.  He didn't suddenly gain armored sleeves, a cape, an ornate helmet, etc., such as what happened when Thor became "worthy" in the first Thor film, or such as what happened when Jane Foster became the new Thor.  And, while The Vision did wield Mjolnir in the battle with Ultron, he wielded it in the hitting/throwing sense of the word, but he didn't appear to have mastery over thunder and lightning like Thor does.
If I may offer an alternative theory, it would be that the source of The Vision's power, the Mind Stone, is one of the five "Infinity Stones", and is therefore an ancient and mystical object of immense power....  Power that is far older and stronger than any spell/curse that Odin could possibly cast on Mjolnir (or any other object).  In short, the Mind Stone's power was unaffected by Odin's rules or even the powers granted to the person/people worthy of wielding the hammer. The Vision, as the embodiment of the Mind Stone is simply too full of ancient power to be subject to mystical limits placed on objects by Odin, who, to The Vision, would be an inferior being.  Basically, that becoming the new Thor would be something of a demotion for The Vision.
Lastly, as a side note, to address the comments of those people who mentioned  various instances when Captain America, Hulk and others wielded Thor's hammer, I would point out that each such instance happened in the comic books during a period of time in which Odin had taken Mjolnir away from Thor as punishment for Thor's defiance in not leaving Earth and returning to Asgard, as Odin had ordered.  Following Thor's being stripped of Mjolnir, Tony Stark created a new hammer for Thor (actually, a hammer on one side and an axe on the other).  The new hammer was as close as Stark could get to the actual Mjolnir as earthly physics and cutting-edge earthly technology would allow.  But the new hammer did have it's limitations, and the whole "worthiness" thing was one of the major limits, as pretty much anyone with enhanced strength could lift it.
Comment: Some quite interesting insights indeed. Welcome to [Movies & TV](http://movies.stackexchange.com/tour) and congratulations to a solid debut answer. +1
Comment: Wait, so then can babies lift Mjolnir?
Answer: This is actually an open question even at the end of the movie. Tony, Steve, and Thor are debating this exact question in the final scene.
There are two possibilities they raise.
First, the easiest answer is, Odin's enchantment found him worthy. If you note, Rogers almost managed to pick up Mjolnir, implying that he is almost worthy, but not quite. Vision, for whatever reason, is considered as worthy as Thor to wield the hammer. Thor tends to believe this is true, which is why he let Vision keep the Infinity Stone. It's possible that is the other way around: because Vision is holding the Stone, that makes him worthy.
The other option is that Vision doesn't count as a "person", since he's an android (meaning, he basically exploited a loophole in the magic). As Rogers surmises, this is no different to putting the hammer in an elevator: the machine would "lift" Mjolnir but he isn't really "wielding" it.

In the comics, there have been several others besides Thor to wield the hammer over the decades, including Cap, so this would have been an unusual and significant event, but not unheard of. It remains to be seen in the MCU if things work out the same.
Comment: So for you the possibility that Vision does not count as a person (as Tony and Cap joke) would be the "non-easy" answer? Meh.
Comment: I think that option opens up lots of other hard questions: can Ultron wield it? Could Tony order a suit to do it? Why couldn't Tony's glove do it?
Comment: Yet those questions seem far less interesting to me than the implications about the Vision's nature that the other possibility brings. But granted, that may be just me.
Comment: I agree its more interesting but I think it also raise a number of contradictions that would have to be explained away somehow.
Comment: So, can all androids lift the hammer!!!!!!
Comment: Then in first movie of THOR why didnt they use lift?
Comment: why didn't who use a lift when? If you mean SHIELD, they were studying the hammer, so they clearly didn't know anything about it.
Answer: It was probably a good way to fast prove to the spectator that Vision is an ally. It can also be that Vision was born because of Thor's thunder. Or maybe it's because Vision is just born and he is absolutely pure.
Answer: I know this is a slightly old question, but-
I've decided that Vision can only pick up the hammer because technically, he's an inanimate object. He's not exactly a human who can be worthy of Mjolnir, so I hint it's kinda the same as when Thor hangs the hammer on a coat rack in one of the Thor movies, I forgot which one.
Comment: He's pretty animated. If he were an inanimate object, he'd be a statue.
Answer: He's not worthy of the hammer. The reason why he picked it up is because of Thor's hammer, which helped bring Vision to life. Technically, a BIT of Thors powers are in Vision.
Comment: The down votes here weren't for the answer, but the bad formatting. This actually makes some sense.


Does a maximal coupling distribution have the highest correlation?

Question: Sampling from a maximal coupling of 2 univariate Gaussians will give you a bivariate distribution which is not bivariate Gaussian. A bivariate Gaussian can be parameterized with a correlation parameter $\rho$. I assume that the maximal coupling distribution will have a larger correlation than the bivariate Gaussian but I might be wrong on this-the maximal coupling could be less correlated than the bivariate Gaussian. Are there any results on the relationship between maximal coupling and correlation?
Comment: The question does not make complete sense in that there is no $\rho$ involved in the statement of the maximal coupling, only marginals matter.
Comment: @Xi'an I agree the the marginals are explicitly specified but the procedure mentioned on Pierre's blog also gives an implied joint distribution over $(X,Y)$ does it not? I was thinking for the normal case you might be able to use a conditioning argument to get to a relationship between covariance of the implied distribution over $(X,Y)$ under the 2 cases in Pierre's algorithm. From this you could get a correlation. Incidentally, I was reading Pierre's blog post and came up with this question-I should've included a link in the original post-thanks for including.
Answer: Pierre Jacob on Statisfaction explains how to implement a maximal coupling between two distributions $p$ and $q$. Which is essentially a sequence of two accept-reject steps. From there you can try to estimate the correlation $\varrho$ between both Gaussian variates.

Here is for instance a comparison of empirical estimates of the correlations, depending on the values of $\mu$ and $\sigma$ (with the other Gaussian being standard):

The correlation associated with a maximal coupling can be derived from
\begin{align*}\mathbb{E}[XY]&=\mathbb{E}[XY\mathbb{I}_{X=Y}]+\mathbb{E}[XY\mathbb{I}_{X\ne Y}]\\
&=\int x^2 p(x)\wedge q(x)\text{d}x+
\int\int xy \{p(x)-p(x)\wedge q(x)\}\{q(y)-p(y)\wedge q(y)\}\text{d}x\text{d}y
\end{align*}

Note that, to answer the question, the correlation returned by maximal
  coupling is a function of the four parameters of the Gaussians, while
  the maximal correlation is always equal to one.
Comment: Marking as correct, thanks for putting this together.


How does one properly utilize Gyms?

Question: How do gyms work in general? Do my Pokemon battle others there? How are the stats taken into consideration if they do battle?
If I leave my Pokemon in a gym that I will not be returning to, can I get the Pokemon back?
Answer: Freekvd's answer covers the basics of gyms, but I think leaves out some important details with regards to Gym mechanics, I have tried to be more thorough in this answer.
Gyms are the only locations (currently) where Pokémon battles can occur. When you are battling at a Pokémon Gym, you are either battling an opposing team, using a full roster of six Pokémon that you have selected, or battling ("training against") your own team, using a single Pokémon that you have selected.
Combat itself is relatively straightforward - single tap repeatedly to perform your Pokémon's basic attack and to charge up your secondary attack, and then long-tap (hold down) to use your secondary attack once it is charged. You can also swipe to the left or right to dodge the enemy's attack, although this is a bit finnicky and the timing can be a bit tricky to get right. Beyond this, the results of a Pokémon battle differ depending on the two types of gyms:
Enemy Gyms
These are gyms that are currently controlled by players who are not on the same team as you (i.e. Instinct (Yellow), Mystic (Blue), or Valor (Red)). When you engage in battle against these gyms, you must pre-select a roster of six Pokémon to fight with. Then you will fight the Pokémon in the gym one by one from weakest to strongest until you have beaten them all (or not). For every enemy Pokémon that you defeat, the prestige of that gym will be reduced. If the prestige is reduced enough, that gym will lose a level and the weakest Pokémon will be kicked out and returned to its trainer. If the gym loses enough prestige and falls below level one, it will turn white (neutral) allowing you to install a Pokémon of your own and claim this gym for your team.
Allied Gyms
These are Gyms that are currently controlled by players who are on the same team as you. When you battle at these gyms, you must select a single Pokémon to fight with, and then combat proceeds as normal against the Pokémon in that gym. Winning these will result in an XP reward, and the prestige of that gym will be increased; however, any Pokémon that you defeat will remain in the gym, unlike battles against enemy gyms. You can also install your own Pokémon in a friendly gym provided there is enough space, which is based on the gym's prestige level (e.g. Prestige 2 gyms can hold two Pokémon). Installing your own Pokémon in a gym can be beneficial because it allows you to collect a reward of Pokécoins and Stardust once every ~20 hours for each Pokémon you have installed in a gym. The maximum any player can have in any singular gym is one Pokémon.
Comment: Does the pokemon you attack, attack back based on AI or can you control the pokemon you add to gyms? You could also confirm what happens when your pokemon is defeated.
Comment: Great answer! I was planning to expand mine but I got stuck running around town for 5 days trying to catch them all.
Comment: "Any Pokemon that you defeat will be removed from that gym..." This is incorrect. The gym loses an amount of prestige for each Pokemon that you defeat. The amount is based on the difference between your Pokemon and the defending Pokemon's CP, if the attacker is lower the gym loses more prestige. Pokemon are only removed from the gym when it loses enough prestige to lose a level, dropping the lowest CP Pokemon first.
Comment: Good catch, sorry my understanding of this has evolved a little bit and I hadn't gotten a chance to update this post, will update it now.
Answer: If you get to a gym that is free, you can put one of your pokemon in there. If the gym's occupied by a player from another color, you will have to beat that player first.
If you put your pokemon inside a gym and it gets beaten, it will be returned to you.
Answer: When you find a allied gym fight it. It will increase the prestige of the gym causing more players to be able to hold it.
A group of friends and I always train at gyms after we caught them till its at least prestige 5 (if you beat a gym and take it over its 3) so players have a much tougher time dealing with them.
Be a team player and train your own gyms. Having a stable is better than capturing and losing gyms
Answer: I call them XP boosters. Once you have strong Pokemon (CP above 1200), find gyms of the two other teams. You can easily beat it using only 2 or more Pokemon. Battles usually last 1 minute or so. Once you beat them you get XP ranging from 150-500.
I have a Vaporeon with CP of 1210. It is strong enough it take out 4 Pokemon max and min 2. I have personally done this to increase my XP and move to higher levels.
And one more thing  never place you Pokemon after you take out the gym. Just leave it move on and find another.

How does one properly utilize Gyms?


Apache and Memory issues

Question: I run a little startup on a Cloud server with 512MB and monitor the CPU/memory consumption with htop and phpsysinfo. Once, the server has ran out of RAM and on some instance get as high as consuming close to 90% of RAM. htop shows apache (httpd) as the top process with some (httpd) process consuming up to 7.5% in some instance. Is this amount (7.5%) too much for a single httpd process? What are the recommendations for reducing apache memory consumption?
Comment: What kind of content is Apache serving?  Static files or does it do any processing?
Comment: Sorry I failed to mention. The site runs on PHP, so Apache does processing. Besides, I have gzip compression turned on but I dont think this should have that big effect on the memory.
Answer: 7.5% for a single child doesn't sound too abnormal, but it all depends on what the child is supposed to do... I run systems with apache and mod_perl and those children get huge.
Watch your apache children memory footprints over time to see if they stabilize.
If not, use MaxRequestsPerChild to control how often they are restarted.
Use MaxClients to limit how many concurrent children you have (to avoid swap or out of virtual memory issues).
In my experience, it's generally a memory bottleneck on the webservers.
Answer: That sounds pretty normal.  To reduce the memory footprint would be to figure out which modules you need and don't need and compile your own version.  Although with dynamic modules maybe that doesn't help as much.
Here is a nice O'Reilly article about getting your Apache memory requirements down. Although a bit old, not sure if has the enhancements that come with Apache 2.

Apache and Memory issues


Any organisation in London that would be willing to show us funtionalities of CiviCRM ?

Question: I am trying to promote civiCRM at my governmental organisation in London and I would be very grateful if I could visit another organisation that uses several functionalities to see how it works live. Mailing and campaigning are the most important features for us. Thank you all for your time. Romina.
Answer: Pleased to hear that you want to promote CiviCRM!
This may not be the best place to ask this question.  You may have better luck on the CiviCRM chat site.
Alternatively you could search for a CiviCRM partner based in London and ask if they can help.
You may also be interested in the CiviCRM meetup in London.
Of course there are also the demo sites if you want to try it out for yourself.
I hope that helps.  Good luck!


Are intra-state and out-of-state online accounts insured by the FDIC?

Question: Are intra state and out of state ONLINE  savings/checking/CDs/money market accounts FDIC insured same as local brick & mortar bank accounts?
Answer: Usually they are, but of course you should check the registration number the bank shows against the FDIC website to make sure you don't fall for a fake.
In case the account is offered by a credit union rather than a bank, they will have insurance through NCUA instead of FDIC, verify NCUA charters here.  This applies to both online and brick-and-mortar credit unions.
Money market accounts in particular may be provided by yet another type of financial firm: a brokerage.  Those are insured through SIPC and there are significant differences in what protection is provided vs FDIC and NCUA insurances.  Note that many brokerages provide a "sweep" service, such that when not actively involved in a trading transaction, money is actually held in a bank account where FDIC applies.  The particular broker should be able to tell you which bank holds the sweep accounts.
Answer: They can be. You will have to check the specific bank's terms to make sure, but there is nothing preventing them from being FDIC insured.


Can a Video/Audio Chat application get rid of its own volume control and depend on master volume control?

Question: Designing a communication software with audio/video chat starts to have a lot of chat controls and the UI starts to get cluttered. I am wondering if getting rid of application's volume control and depending on master volume control of the computer is a good UX or not.
Comment: As a user I would say no, I like to be able to manage the audio volume from the apps that generate audio themselves, to balance everything out with the other apps. This can be done using the volume mixer (on Windows), but that may be too advanced for some users.
Answer: Unless your application will be the only application running (for example, you are designing this for a kiosk) then I suppose it can work, but for all other applications this is not a good idea for many reasons:

As a user, I would like to mute only your stream, without muting the entire system; which is not intuitive at all for most users. It is possible with a few right clicks on Windows (haven't seen this option on macOS), but it is not intuitive at all.
Why work against the tide? It has become the de facto standard that video players have a play / pause or stop button, a timeline / scrubber, and a volume control in that specific order at the bottom of the widget. Your users will be accustomed to see things that way.

You can hide the control bar when the cursor is not in focus on the video stream, and only display once the mouse moves over the stream - this is often how full screen media applications work, but it doesn't mean you can't try it as part of a larger user interface.
Comment: I should have added that there's already a mute button which exists separately on the audio controls. I am trying to imagine how many people lower volume (not mute) of a video/audio conference to listen to something else. Especially, in a business scenario.
Answer: I agree with @BurhanKhalid answer. I just wanted to point out an idea. Apps could be left without individual volume controller if none of them have one and all relied on the system volume controller (a single controller). Apps would still need a mute button though.
This gives the user less control but a simpler experience. If I am not wrong this is how it works in most phones.
Comment: On iOS and Android, there are different channels and volumes can be adjusted for each individually - this means you can set "media" lower than "phone". The volume controllers change depending on the context, so when you are playing a media file, the volume controls adjust that specific channel. As far as I am aware, only the iPhone has a universal mute button, which mutes all channels.
Comment: Well, it divides the volume on the most specific phone tasks, at least in my Android, which are: phone, alarms, everything else. On a pc, I am not sure which would these "main categories" be.
Comment: It depends on the operating system. MacOS only has one master channel, which controls everything coming out of the speakers. On Windows, each application that is playing a stream gets its own channel, so you can (although it  is not obvious and definitely not intuitive to many), control the volume of your browser individually. These extra channels are only shown when something is playing though; so if nothing is playing through your browser, you won't have a channel to control - and finally, to make matters worse, it is upto to the application to support this and not all do.
Comment: On MacOS apps can have an individual control (inside the app), although it is not displayed in a main control-board as on Windows. I guess the point is either All or None. Thanks @BurhanKhalid, great thoughts on the subject!


What are the state-of-the-art meta-reinforcement learning methods?

Question: This question can seem a little bit too broad, but I am wondering what are the current state-of-the-art works on meta reinforcement learning. Can you provide me with the current state-of-the-art in this field?
Answer: One of the most recent papers on meta-RL is meta-Q-learning. This paper introduces Meta-Q-Learning (MQL), a new off-policy algorithm for meta-reinforcement learning (meta-RL). MQL builds upon three simple ideas.

Q-learning is competitive with state-of-the-art meta-RL algorithms if given access to a context variable that is a representation of the past trajectory.

Using a multi-task objective to maximize the average reward across the training tasks is an effective method to meta-train RL policies.

past data from the meta-training replay buffer can be recycled to adapt the policy on a new task using off-policy updates

Experiments on standard continuous-control benchmarks suggest that MQL compares favorably with state-of-the-art meta-RL algorithms.
I think that other references to other work on meta-RL are present in the experiments part of the MQL paper.
Answer: Meta-Reinforcement Learning can refer to a broad range of ideas. Also, different algorithms are SOTA under different evaluation metrics (sample efficiency, agent performance, adaptation speed on a new task, etc)
Assuming that you are referring to the problem of quickly learning/adapting to a new task by training an agent on a distribution of related tasks, the following are some popular algorithms

PEARL [Rakelly et al., 2019]
VariBAD [Zintgraf et al., 2020]
Meta-Q-Learning [Fakoor et al., 2020]

References:

K Rakelly, A Xhou, D Quillen, C Finn, S Levine - Efficient Off-Policy Meta-Reinforcement Learning via Probabilistic Context Variables, ICML 2019.
L Zintgraf et al., - VariBAD: A Very Good Method for Bayes-Adaptive Deep RL via Meta-Learning, ICLR 2020.
R Fakoor, P Chaudhari, S Soatto, A J Smola - Meta-Q-Learning, ICLR 2020.


What's the best way to pay tolls on a cross-country road trip in the US?

Question: I'm driving from Virginia to Washington state later this month. In Virginia, I use an EZ-Pass device that automatically pays my tolls. But I understand that these devices are regional. When driving cross-country, am I best off just using quarters? Or can I buy 1-2 more devices to cover tolls across the entire country?
Comment: In a word: Cash.
Comment: wave of the future: Golden Gate Bridge no longer accepts cash. If you do not have a transponder, there are places you can pull off to buy a one-time ticket.
Answer: Depending on which route you take you may pass through at least 2 or 3 Electronic toll collection systems you can find most of them on the Government Services Administration page.
If you take the most direct route via West Virginia, Ohio, Indiana, Illinois and then via I-90 to Washington, you might need EZ Pass, Mn Pass, and Washington's Good to Go.
You can look at other states that have the Electronic Toll collection systems unaffiliated with other states like California, Texas, Florida, Oklahoma, Colorado, and Kansas.  So generally I wouldn't bother with buying the transponders from them just keep some cash on hand for now and wait until you get License Plate billing technology installed like in Canada or Israel.  California seems to be moving in that direction...
Comment: Florida and Colorado have license plate billing. Most states between VA and WA don't have many, if any toll roads.
Comment: +1 esp. for the useful GSA link. FWIW however, MnPASS is only required if you want to use the "Express Lanes" on certain highways; the regular lanes remain toll-free. Similarly, the only mandatory toll facilities in Washington are the Route 520 Bridge and the Tacoma Narrows Bridge; no need for a Good to Go if you won't be taking them.
Comment: @choster Amended (slightly)
Comment: @xpda True.  Didn't pay enough attention to those states.
Comment: Kansas has a few toll roads. Most of I-35 from just north of the OK/KS border, up to Topeka, then Kansas city is toll.  You may drive on a small portion of that if crossing the state from west to east.


Keyboard types correctly in one account/wrong in another Windows XP

Question: I'm helping a friend with an old XP laptop. When trying to do something simple like typing "msconfig" in Safe Mode in the User account, the only thing that shows up is "0sc6nf5g". If I log in as admin in safe mode and I type I get "msconfig". Anyway of fixing that without creating a new account?
Answer: Check if NUM LOCK is turned on. On laptops without separate number keypads, keys on the right hand side of the keyboard often do double duty as a numeric keypad.
Answer: Check your KB layout options on the user with the issue. It sounds like it could have been set to an alternative layout.


Burninate the width and height tags

Question: Burninate width and height. There are no experts for these things.
( Please no arguments like "there are measurement experts who might specialize in width" :P )
Searching for the tags isn't better than searching title/body, it doesn't categorize questions better.
Comment: Sad to say my particular expertise applies only to length and depth, so I can never answer these width and height questions.
Comment: NO `girth` tag? Everybody knows it's really the girth that matters.
Comment: 6887 unique questions, and it does not help on any of them! If that's not something for nuking from orbit...
Comment: Isn't [tag:height] a JavaScript library though? So is [tag:width] probably.
Answer: Update (15th July 2015)
After doing a bit more research I'm now fully under the impression that neither of these tags should be burninated.

A similar question with similar voting patterns, Do we really need [max] and [min]?, was status-declined by Shog9 ♦ for the following reason:

...as I can tell, these tags are generally used properly: to reflect specific concepts present in the question. There are a bunch more like this. At worst, they're not doing any harm, and perhaps for a few people with specialized interests they're helpful.

SE Meta's When to burninate thread asks the following questions:

Does it describe the contents of the questions to which it is applied? and is it unambiguous?
Is the concept described even on-topic for the site?
Does the tag add any meaningful information to the post?
Does it mean the same thing in all common contexts?

I feel the answer to all of the above questions is: yes for both the height and width tags. Under the above criteria there is really no need to burninate either of the tags.

Original Answer
As the now-top user for the height tag I'm going to defend my shiny tag. This comes after a lot of questions which previously had the tag have now had the tag removed. "Removed the tag for burnination", for instance. This doesn't help anyone, and I'd like to keep my pretty bronze badge* if I can.
* Which had to be re-awarded to me after someone removed the Height tag from one of the questions I'd answered. :-(
Before I continue, I'm going to quote following exerpt from the What are tags, and how should I use them? page:

A tag is a word or phrase that describes the topic of the question. Tags are a means of connecting experts with questions they will be able to answer by sorting questions into specific, well-defined categories.
Tags can also be used to help you identify questions that are interesting or relevant to you.

To counter your arguments why these tags should be removed I'm going to breakdown your post:

No experts ... it doesn't categorize questions better

I disagree with this. Height and Width may not be things which people can be experts in, per se, but they certainly do help sort related questions - and clearly a lot of people do add these tags to their questions for that very reason. If your problem is entirely height or width-related, why not add the tag in?

searching for the tags isn't better than searching title/body

Incorrect. I personally have used the search query [css] [height] in the past for finding questions to answer which are explicitly about height and involve CSS. If you do a search for [css] [height] you'll find 1,937 questions. If you do a search instead for [css] "height" you'll find a mix of over 70,000 questions and answers - the most voted being the answer to the question How do CSS triangles work?; a question which is very loosely related to the concept of height, if at all.

If we're to burninate height and width, we're also going to have to burninate all other conceptual tags - whitespace, for instance. Are there really any whitespace experts out there?
Comment: Perhaps specific uses of width/height can be split off, but I don't see any use of a general width/height tag.
Comment: @bjb568 In CSS `width` and `height` are actual property names. Questions concerning widths and heights may not necessarily relate to those properties, so I feel tags named Height and Width would be more appropriate in this situation.
Comment: Make a css-width tag? I do think whotespace is a bad tag.

Burninate the width and height tags


USB hub powering the Pi and a HDD

Question: I have a Raspberry Pi 3B, a powered USB hub, and an external USB drive.
The HDD is connected to the Hub, and the Hub to a power outlet.
But going from the Pi, do I really need 2 cables (one for power, going into the micro-USB plug, and another from a big USB to the hub-disk) ? I tried with just the micro USB (to the hub) but the HDD is not detected, and I read somewhere that the Pi's micro USB is "power only".
Comment: That is correct the Pi's micro USB connector is designed to supply power to the Pi, there are no data lines from the connector. Although it is possible to power the Pi through the GPIO pins. For transferring data you are limited to the USB ports, Ethernet port, or you could use the Pi 3's built-in Bluetooth.
Answer: If this will work at all you need 2 cables. It MAY work with some hubs, but a compliant hub will not supply sufficient current to run the Pi reliably and most non-compliant hubs supply too low voltage.
Comment: I have been running the Pi (without the HDD) for some time powered from the hub, so it seems "compliant-ish" so far. I'm not sure I understand your reply: are you saying "it MAY work" with just one cable ? Or commenting on powering the Pi from a hub, even with 2 cables ?
Comment: It MAY work with 2. Definitely not with 1.
Answer: You need both cables.
I disagree with Milliways statement that it may work with some hubs - the Pi 3's micro USB connector is definitely power only. If you take a look at the 'POWER IN' section of the Pi 3's schematics, in the top left corner of the diagram, you can see that the middle three pins (Data +, Data -, and USB OTG ID) aren't connected to anything.

There is absolutely no way that anything other than power can be transmitted through that connector.
Comment: And from the regular size USB ports, you can power the Pi but not on startup, from what I read ?
Comment: [*Probably*](http://raspberrypi.stackexchange.com/questions/4035/can-the-usb-ports-be-used-to-power-the-raspberry-pi). The linked question contains a few caveats that you should be aware of if you're planning on trying to back power a Pi.
Comment: Even if the pi's microUSB jack took data, you cannot power via a master connection -- masters power slaves and not vice versa, so if you connected the jack as a master to receive data from slave devices on the hub, it would not receive power to turn on the pi.  This is a good reason for the jack to be power only; otherwise you'd be encouraging people to backpower via the pins and use that as a data link.  OTG connections allow power to a pseudo-master (as with the Pi Zero, and smart phones), but then you need a special hub and to decide what role the Pi is going to play.
Comment: @goobering the comment "may work with some hubs" is because some hubs have no power control and just provide 5V, so you can draw as much current as the PSU is capable of. My experience with these is, however, that they do not always give 5V. My guess is that they just use diodes for isolation. My answer said "If this will work at all you need 2 cables" and never claimed there was data.
Answer:
going from the Pi, do I really need 2 cables (one for power, going into the micro-USB plug, and another from a big USB to the hub-disk)?

Yes, but contra the other answers this doesn't have to do with the nature of the Pi's microUSB connector, it has to do with the way USB hubs in general work.  Even if that microUSB connector did accept data, it could not be used for power and hosting at the same time (OTG connections can, but they are a special case).
This is because USB hubs normally have one special connector which is the data uplink connection to the host they are to be used with. The reason there's only one is because you can use a hub to connect multiple slave devices to one master, but not to multiple masters.  I.e., you cannot connect a drive to a hub, your desktop to a hub, and your laptop to a hub and access the drive from both computers.
In fact, naively trying to do so might damage the computers, since the USB master-slave relationship is not symmetrical.  The issue damage wise is that masters may provide power to slaves but not vice versa.  If you try to hook up two computers using the normal ports on a USB hub, the hub will try and power the computer and the computer will try and power the hub.  One of the voltage regulators will win and circuitry on the opposite side may then get damaged (which may perhaps lead to damage on both sides).
So the connection from a normal port on the hub to the microUSB power jack on the Pi provides power.  You can "backpower" at least some pis (perhaps only older models, I'm not sure) via the normal USB jacks, but this is a risky idea.  Further, if you do that, you still won't be connected to the drive because a slave does not connect to a slave on the same hub.  Only the master does, and again, there is only one of those.
Generally the data uplink port will be a nonstandard size connector on the hub.  There is a picture here with explanation of how this is supposed to be set up.  The data uplink cable is the one with red dots.  Notice it does not connect to a normal port on the hub.
Make sure you do that properly or again, there is the possibility of damaging the pi and/or the hub.
Comment: Before that, I thought things were somehow symmetrical, but your master/slave explanations make a lot of sense now ! Actually this is enforced by hardware to a degree, with male vs female USB plugs. This is what prevented me from mis-plugging the 2nd cable: the hub indeed has a special uplink port, and I HAD to use it, lacking a male/male cable.

USB hub powering the Pi and a HDD