Wave-particle duality is the uncertainty principle in disguise - <AUTHOR> http://phys.org/news/2014-12-quantum-physics-complicated.html

<comment><USER2> This article gets the paper totally wrong. Learning that the uncertainty principle gives rise to phenomena that popular science calls "wave-particle" duality was taught to me in quantum 101.

From the abstract: "This idea...upper bounds the sum of the interference visibility and the path distinguishability. Such wave-particle duality relations (WPDRs) are often thought to be conceptually inequivalent to Heisenberg's uncertainty principle, although this has been debated."

I'm quite surprised that anyone would think that those relationships wouldn't be direct consequences of uncertainty. They are directly analogous to position and momenta quantities.

"Here we show that WPDRs correspond precisely to a modern formulation of the uncertainty principle"

No surprises here.

<comment><USER3> > Learning that the uncertainty principle gives rise to phenomena that popular > science calls "wave-particle" duality was taught to me in quantum 101.

Agreed, just to expand on that: The hand-wavey relationship between wave- particle duality and the uncertainty principle was taught to me like this...

Imagine you have a sine wave. It has a well-defined momentum, p, given by its wavelength. However, since it's infinitely periodic in space, it has no well- defined position, x.

Now consider a wave-packet[1]. This has a very well-defined position, given by the centre of the packet, but no well-defined wavelength/momentum.

These are the limiting cases. The Heisenberg uncertainty principle, ΔpΔx >= ħ/2, just quantifies this relationship. If you try and measure x, the wavefunction ends up more 'packet-like' and you can no longer measure p as well, and if you try and measure p, the wavefunction ends up more 'wave-like' and you can no longer measure x as well. That's all there is to it.

It's not exactly rigorous, but I don't think this explanation is too misleading either (though I'd be happy to learn otherwise!).

[1] [https://en.wikipedia.org/wiki/Wave_packet](https://en.wikipedia.org/wiki/Wave_packet)

<comment><USER4> Just a minor correction, but a wave packet isn't the limiting case. Something that approaches a delta function is.

</comment></comment></comment><comment><USER5> Perhaps I was mistaken, but I thought this was sort a necessary revelation when learning about QM. It's been years since I took Atomic Physics, so perhaps this is something much ... deeper?

Was it a serious idea that upon measurement the particle _literally_ lost it's wave properties? Like, there were actually two separate approaches to the math? I know we made some efforts to simplify in class, approximating as particles and such due to the drastically simplified math, but we all knew that was happening; the professor was reasonably explicit about it. EDIT: As in, I remember us going over the evolution of a waveform, and how boundaries affect the solutions, and how uncertainty causes the particles to have field distributions that just happen to be the wave solution of the particle.

I'm completely serious about being confused here: QM is super easy to misunderstand, and I'd love to feel the eureka this article is trying to convey.

<comment><USER6> The mythical "wave or particle" interpretation of wave-particle duality is oddly persistent, and is not only pervasive in popular science but I've heard it repeated by serious physicists also, even though it's unsupported by the very math they work on.

<comment><USER7> It's not clear to me what you think the "wave or particle" interpretation _is_ , nor what you think is wrong with it, nor what you think you've heard "serious physicists" say.

</comment></comment></comment><comment><USER8> <armchair physicist>

I love reading about these things. It seems like information is slowly being raised to the same level as energy and matter (All being different ways to look at the same phenomenon)

The universe does care about preserving information, and there are physical limits on it's propagation and consumption. This is similar to formalizing energy as a concept, which can manifest itself in many different ways (kinetic, potential, radiation, etc) Once we wrapped it up in a concept we were able to reason about it in a more abstract way. The same process is now happening with the concept of information. This is leading to breakthroughs in computing (ML, pattern recognition, etc) and physics. I am excited for the future of information theory.

</armchair physicist>

<comment><USER9> Take a look at David Deutsch's work on quantum mechanics, information theory, quantum computing, etc. I especially like [http://arxiv.org/abs/1405.5563](http://arxiv.org/abs/1405.5563)

Cool stuff.

(Related, possibly, is the concept that QM is simply probability with ranges from [-1,1] instead of the traditional [0,1]: Negative probabilities imply things that happen that we cannot measure. Or something like that, it's been a while.)

(Now if only I could find that wicked cool graphic showing the hierarchy of mathematics (ZFC or something near the bottom) and physics (QM and GR, sitting atop currently irreconcilable branches of math)....)

<comment><USER10> I found the diagram you mentioned:

[http://24.media.tumblr.com/tumblr_lil7n0uiEl1qfjvexo1_500.pn...](http://24.media.tumblr.com/tumblr_lil7n0uiEl1qfjvexo1_500.png)

<comment><USER11> The original source of this diagram: [http://arxiv.org/abs/gr- qc/9704009](http://arxiv.org/abs/gr-qc/9704009)

</comment></comment></comment></comment><comment><USER12> I'm no theoretical physicist, but I thought wave-particle duality was solved a long time ago by quantum field theory. Feynman, for instance, was able to formulate electromagnetism fully in terms of particles, using his path integral formulation. Since this formulation computes probability amplitudes, it seems to fit well with the uncertainty principle. This approach gave rise to QED, the most accurate physical theory ever developed.

In other words, without more detail, and not being a physicist myself, I can't tell what's actually new here.

<comment><USER13> You are right, quantum field theory is perfectly capable of explaining both phenomena (but not in terms of particles but rather in terms of descrete field modes). The idea that it is connected to the uncertainty principle is even older.

Reading this article made my kind of angry, as it implies that wave-particle duality was not understood until now. Like here:

> _" has proved that two peculiar features of the quantum world previously > considered distinct are different manifestations of the same thing"_

I frequently encounter this _mysterious_ yet-to-be-understood duality in esoteric discussions (with all kinds of wrong conclusions of course). I think that ultimatly, whenever we teach someone about the paradox behavior of particles/waves, the very next sentence should be "but this is perfectly understood and not paradox at all". While we are at it, instead of saying

> _" this is what happens until you sneak a look at which slit a particle goes > through"_

we should say, "this is what happens unless you bombard the particle with photons, which changes everything, of course".

<comment><USER14> Richard Feynman said that only about 6 people understand quantum mechanics."perfectly understood" is an overstatement.

<comment><USER15> I understand it perfectly. I'm not sure what an eigenvalue is, though, but I'm sticking to my claim of understanding.

</comment></comment></comment></comment><comment><USER16> [http://arxiv.org/pdf/1403.4687v2.pdf](http://arxiv.org/pdf/1403.4687v2.pdf) is the actual preprint.

I'm finding it pretty hard to parse. It seems to be a reformulation of what we already know about non-commuting observables in terms of entropy/ignorance. I might need to read some of the cited papers to understand exactly if that's significant and why.

</comment><comment><USER17> I know that many people feel that you have to write like this to get anyone to pay attention (maybe they're right), but after enough years in physics, the breathlessness of this kind of reporting really starts to grate.

> international team of researchers has proved

> made the breakthrough

> discovered the 'Rosetta Stone'

I haven't read this particular article carefully, but I think it's safe to assume that words like "reformulated," "clarified," "extended," or "embedded in a new framework" would be more appropriate. Which is fine. New and better explanations are useful and important.

But despite what you may read, we don't find a new Rosetta Stone for quantum physics every year.

I get much more excited about science writing where the reader can come away with a better understanding of an actual concept, rather than just a sense that someone somewhere is doing something hard and smart.

<comment><USER17> To put it another way, I think you are much more likely to absorb powerful ways of thinking while being entertained if you read [https://what- if.xkcd.com/](https://what-if.xkcd.com/) than if you read [http://phys.org](http://phys.org)

What If shows by example that you can apply quantitative reasoning to the most outlandish situations and actually draw interesting distinctions and conclusions.

Phys.org style reporting urges you to accept by argument from authority that the universe is mostly made of dark energy, and gravity is made out of particles traveling backwards in time through 11 dimensions or whatever it was I read last month I can't quite remember. These ideas come from actual serious research, but they aren't powerful when presented this way because you can't apply this style of reasoning successfully unless you have tons and tons of training working in the specific areas they report on.

</comment></comment><comment><USER18> [http://arxiv.org/pdf/1403.4687v2.pdf](http://arxiv.org/pdf/1403.4687v2.pdf)

</comment><comment> SO2Bohr-ed Feynman on the "work" of gravity theorists: "something correct that is obvious and self-evident, but worked out by a long and difficult analysis, and presented as an important discovery"

To be fair, this case is the fault of the journalist(s), not necessarily the research itself.

</comment><comment><USER19> > The particles pile up behind the slits not in two heaps as classical objects > would, but in a stripy pattern like you'd expect for waves interfering. At > least this is what happens until you sneak a look at which slit a particle > goes through - do that and the interference pattern vanishes.

Could any of the physicists here verify whether it is the case that detecting the slit the particle passes through destroys the interference pattern. I had the impression that the path of the photons could be determined without destroying the pattern.

<comment><USER2> Detecting which slit does destroy the interference pattern, yes.

</comment></comment><comment><USER20> Tangential comment: if you are interested in quantum mechanics then you may be interested to read about "Bohmian Mechanics".

I became interested in Bohmian Mechanics after reading an email exchange between Sheldon Goldstein & Steven Weinberg [1]. It contains a few quite entertaining quotes, in particular:

        > And since Bohm's equations make exactly the same
        > predictions as those of ordinary quantum mechanics,
        > it is not clear what is accomplished by adding the
        > complication of guiding waves, except to restore a
        > sense of sanity to the whole affair.

Scott Aaronson has a brief introduction to Bohmian Mechanics at the end of his notes on decoherence and hidden variables [2]:

        > Again, the amazing thing about this theory is that it's
        > deterministic: specify the "actual" positions of all the
        > particles in the universe at any one time, and you've specified
        > their "actual" positions at all earlier and later times.

Scott's perspective is particularly interesting because he points out some limitations of Bohmian Mechanics. To paraphrase badly, the deterministic particle trajectories obtained from Bohmian Mechanics rely upon dealing with actual particles, position, momentum, in infinite dimensional spaces. It doesn't give you deterministic behaviour in the finite dimensional spaces that computer scientists prefer.

Some proponents of Bohmian Mechanics point out that the theoretical predictions of deterministic particle trajectories for the famous double-slit experiment agree with recent experimental results.

Theoretical predictions: see Figure 1, page 14 of [3], which is an adaptation of a figure from [4].

Experimental results: see Figure 3, page 1171 of [5].

Note that [5] carefully frame their experimental results as "Using weak measurements, however, it is possible to operationally define a set of trajectories for an ensemble of quantum particles".

For further reading, please see [6] for links to introductory writing about Bohmian Mechanics.

[1]: [http://inference-review.com/article/on-bohmian- mechanics](http://inference-review.com/article/on-bohmian-mechanics)

[2]: [http://www.scottaaronson.com/democritus/lec11.html](http://www.scottaaronson.com/democritus/lec11.html)

[3]: [http://www.mathematik.uni- muenchen.de/~bohmmech/BohmHome/fil...](http://www.mathematik.uni- muenchen.de/~bohmmech/BohmHome/files/Introduction.pdf)

[4]: "Quantum interference and the quantum potential" \-- Philippidis, Dewdney, Hiley -- Il Nuovo Cimento B, 1979; [paywalled article] -- [http://link.springer.com/article/10.1007/BF02743566](http://link.springer.com/article/10.1007/BF02743566)

[5]: "Observing the Average Trajectories of Single Photons in a Two-Slit Interferometer" \-- Kocsis, Braverman, Ravets, Stevens, Mirin, Shalm, Steinberg; Science, 2011 -- [PDF] [http://materias.df.uba.ar/labo5Aa2012c2/files/2012/10/Weak-m...](http://materias.df.uba.ar/labo5Aa2012c2/files/2012/10/Weak- measurement.pdf)

[6]: [http://www.bohmian- mechanics.net/whatisbm_introduction.html](http://www.bohmian- mechanics.net/whatisbm_introduction.html)

<comment><USER16> I don't find Bohmian mechanics any more satisfying than regular QM. In an effort to formulate a 'hidden state' that makes QM make.. sense.. you add a guiding wave equation that depends on the state of the universe? That's not better at all.

I'm all for trying to formulate QM in a way that doesn't offend basic sensibility, but I'm not convinced this is it. I don't think deterministic- but-nonlocal is better than nondeterministic-but-local.

<comment><USER21> Standard quantum mechanics only has the wave function. The thing you object to in Bohmian mechanics is the wave function. Both are nonlocal. You should object to both.

In particular, standard quantum mechanics gets results of experiments by collapsing the wave function. That is, it takes something which is universe spanning and it collapses it to something, with the collapse based on what a physicist does in a laboratory. That, of course, should seem rather absurd. To get around that, you have to add something either particle positions, a matter density, flashes, etc. You need results to experiments in a theory. Without something (and collapse from experiments is adding the collapse mechanism + external experiments, whatever that means), you do not get results. So the theory is a complete failure.

Only many worlds is not non-local (it adds a matter density by integrating the wave function appropriately), but they escape it by not having results of experiments at the time that history records there were results. I think. That theory makes me a little dizzy at times.

Also, the hidden state of BM is not hidden. We have a basic sense that stuff has positions. That may be an illusion, but Bohmian mechanics says that we can choose a theory that does not have that be an illusion. The thing that is hidden, that is deduced from the behavior of stuff which we see, is the wave function.

What BM explains is why it seems that our world is particle-like and why we have singular outcomes to experiments. All done naturally. Sure, the nonlocal nature is a problem that we are still trying to understand, but so what? No one has got the full story yet and so BM is viable and gives a great intuition about QM (the standard QM (operators, collapse) is a derivable formalism, like thermodynamics from Newtonian Mechanics).</comment></comment></comment>


Ask HN: Grad School - <AUTHOR>

It is approaching about that time where I need to decide on whether I should go to grad school or not (I am currently an undergrad). My future goal is to start a start-up, but I don't feel 100% about anyone else I know right now to be my co-founder. Therefore, I am stuck now on deciding whether it is better worth my time just heading over to Silicon Valley and getting involved there and hopefully meeting a co-founder (I have never been there, is this asking for a miracle?) or going to a school like Stanford or UC Berkeley, which would require me to take out a loan and be in some serious debt. I would probably go for a masters degree as opposed to a PhD since I am assuming a PhD is setting myself up to drop out at some point (I don't intend on it taking 6 years to find a co-founder). Is there any reason I should be thinking PhD instead? Also, how certain were any of you that you knew you had the right co-founder at the time of starting your company? I'm not looking for someone to tell me exactly what to do as much as give me more information about why one option may be better or worse than another from the viewpoint of someone who is currently involved in the start-up world. <comment><USER2> Well, as someone who has worked in startups for three years. I think you should at least take on an internship with a startup to see how much you like working in a startup. There is a pretty big financial cost with going to grad school especially if you do a masters. I know that payrates for a person fresh out of a masters program is comparable to the payrate of an undergrad who worked for 2 to 3 years. My opinion is that getting some real world experience is always good before you start your own company.

<comment><USER3> I second this opinion, particularly regarding real world experience.

I was in a similar situation when I graduated, deciding whether or not to apply for graduate school. I decided to take an internship after I graduated for two months which eventually turned into a full-time job.

I know it's difficult among our generation (Generation Y) to be patient about something important, i.e. a job, graduate school, your own company, etc, but you'll see it'll pay off down the road.

Also, what did you want to study?

Good luck.</comment></comment>


Review our team brainstorm tool: GroupZap - <AUTHOR> http://groupzap.com

<comment><USER2> Nice work. It might be easier to make the entire canvas draggable like google maps instead of the separate zoom control.

While it's nice and easy to be able to start using without making an account, it's a pain to find a whiteboard I created once I left the site. I know it's in my inbox, but you might want to provide a login or a memorable URL once people have got started with their email address.

<comment><AUTHOR> Thanks, appreciate the feedback.

Did you get a chance to try it with a someone on your team? Thats when the software really comes alive we feel.

Let me know if you'd like a free board for a year.

</comment></comment><comment><USER3> The double click for edit does not work in Opera 11.10 beta on Linux. Only Opera's context menu shows up.

Rotating and zooming is painfully slow and without any visual clue (i don't know if my movement will rotate or change size, maybe just becouse of the slowness?). Is there a reset size/rotation button?

<comment><AUTHOR> Thanks for trying it blick. Do you use any other browsers and did you have the same problem?

<comment><USER3> Yes, after encountering the problem in Opera, i switched to Firefox 3.6 (don't have 4 yet) and encountered the slowness. Next i tried Chromium 11, but my whiteboard there is only in Viewing mode, even though i used the same e-mail address, which worked in Opera and in Firefox.

</comment></comment></comment><comment><USER4> Great work! I built something similar to this but you've just really taken it to the next level utilizing HTML5. Nice!

<comment><AUTHOR> cool what did you build? what improvements could we make and would you use it with your team?</comment></comment>


Acrobat Reader for Linux removed - <AUTHOR> http://get.adobe.com/reader/otherversions/ <comment><USER2> The solutions here seem to be split into two camps:

1\. Use Okular / Evince / Poppler / Sumatra / Zathura / whatever (actually, I think you might begin to see the problem already).

2\. Use Acrobat Reader in Wine.

Neither of these is going to appeal to my family members whose idea of a good time is not installing something via "Software Center" and spending ages tweaking the configuration to work properly, so they can use a half-speed version of Acrobat Reader on Windows. They will probably end up sticking with Mac or Windows.

Which is perfectly fine, because no one is forcing them to use Linux. I just want to point out that stuff like this totally kills the idea of "Linux for the everyday user". First you _have_ to offer them a lot of the stuff which they are accustomed to (a decent document editor, a decent PDF reader), then slowly increase their awareness about software freedoms. It is unfortunate that most FSF zealots end up reversing this order, and driving away the common user.

Solutions? I'm not sure, maybe someone can weigh in. The best I can think of right now is for organizations like Canonical and Red Hat who might be interested in promoting Desktop Linux to pay for Adobe to release and support Acrobat on their distros. Either that, or actively put in some sort of a translation chart in the OS for common users "Acrobat <-> Evince" or such.

<comment><USER3> I upvote this. Especially the Wine option. IMHO it should be advertised that "You can run Windows programs on Linux by using Wine".

</comment></comment><comment><USER4> Are there any Linux PDF readers that work as well? For instance I reported this bug [https://bugzilla.gnome.org/show_bug.cgi?id=628920](https://bugzilla.gnome.org/show_bug.cgi?id=628920) years ago but the example PDF I included still looks horrible in the latest Evince. So I typically keep a copy of Adobe Reader installed to deal with files like that, but I'd love to replace it with something open source.

<comment><USER5> Your primary choices in renderers are the following:

        - XPDF - the OG *nix PDF renderer.

        - Poppler (fork of xpdf). Probably most featureful,
          different features supported among different
          implementations (e.g. Evince and Okular appear to
          behave differently and have different feature sets).

        - Mupdf, newer code base, made by Ghostscript team. Only
          supports rendering PDFs and XPS. No fancy javascript
          or form support.

        - PDF.js via Mozilla browsers.

        - PDFium via Chrome-based browsers.

<comment><USER6> PDF.js is not limited to Firefox. Here's a Chrome extension: [https://chrome.google.com/webstore/detail/pdf- viewer/oemmndc...](https://chrome.google.com/webstore/detail/pdf- viewer/oemmndcbldboiebfnladdacbdfmadadm)

</comment></comment></comment><comment><USER7> Good riddance, I guess? I believe there isn't any shortage of good PDF viewers for GNU/Linux.

<comment><USER8> What PDF readers on linux are 'best recommended'? I compared acroread with evince and kpdf in the past and found that acroread was the most parsimonious in use of resources (especially RAM on large documents). Have not repeated the comparison recently, so will be glad to hear about recommendations with more recent experiences with large documents with images.

<comment><USER9> Personally, i prefer "zathura". besides filling out forms it can do everything, with a very sleek ui and outstanding keybindings (vim-esque). I encourage you to try it :)

<comment><USER10> It's a fantastic piece of software. It can use different backends (mupdf or poppler) and it can also deal with DjVu files.

</comment></comment></comment></comment><comment><USER11> Okular[1] is the best PDF Reader on Linux. Enough said.

[1][http://okular.kde.org/](http://okular.kde.org/)

<comment><USER12> What does it provide that other options like zathura doesn't? Just asking; no offense intended.

<comment><USER13> Mostly KDE itegration and support for a really broad array of formats. Most people probably don't use it as such, but it's more of a general document viewer. (For example, you can actually open Microsoft .ppt files with it.)

It's a great pdf viewer, and has plenty of features, but so do most of the other well-known ones.

I love it, but I'd probably use something else if I wasn't using KDE as my desktop environment. It's lightweight if you're already loading all of the KDE libraries, but rather heavyweight otherwise.

<comment><USER11> I had been using it long before I started using KDE. There aren't many PDF Viewers that could do annotations and handle 1000 page PDFs. Evince which is a premier Gnome PDF application is pretty basic.

</comment></comment></comment></comment><comment><USER14> Here is one way to get it back

Source: [http://askubuntu.com/questions/89127/how-do-i-install- adobe-...](http://askubuntu.com/questions/89127/how-do-i-install-adobe- acrobat-reader)

sudo add-apt-repository "deb [http://archive.canonical.com/](http://archive.canonical.com/) $(lsb_release -sc) partner" [you can use use 'precise', 'quantal', or 'raring' instead of the '$(lsb_release -sc)' command]

sudo apt-get update

sudo apt-get install acroread

Also, Adobe still maintains an archive of all versions of Reader on their FTP site. Trivia - here is the OS2 version: ftp://ftp.adobe.com/pub/adobe/acrobatreader/os2/3.x/

The latest Linux release is at ftp://ftp.adobe.com/pub/adobe/reader/unix/9.x/9.5.5/enu/

</comment><comment><USER15> I hope that there is no secret that the company is Adobe doing everything to ensure that its products were not released under Linux systems.

<comment><USER16> I really wonder where this attitude from Adobe comes from. I mean in the past they seemed always close with Apple. That could have explained the attitude. But then Apple refused to ship Flash and released alternatives to Adobe products. It really seems like a bad business attitude from Adobe.

<comment><USER17> Adobe wasn't really that close with Apple, Adobe's customers were. Adobe wanted their customers to move to Windows.

</comment></comment></comment><comment><USER18> I have some people who send me corrections via PDF annotations and notes. Neither Evince nor XPDF fully support these. Highlighted annotations particularly, Evince shows the highlight but doesn't show the annotation text (no icon to show it, hovering doesn't do anything either). I need Adobe Acrobat Reader for that.

My Poppler is a bit out of date, though it's not clear to me whether more recent versions of Poppler support highlighted annotations fully:

[https://bugzilla.gnome.org/show_bug.cgi?id=583377](https://bugzilla.gnome.org/show_bug.cgi?id=583377)

<comment><USER19> What about the firefox built-in pdf reader or google docs?

<comment><USER18> Google Docs has the same behaviour for me as Evince on annoted-highlights: shows the highlight on the text, but doesn't show or provide anyway to view the associated annotation.

Edit: Remove IIRC - justed tested Google Docs again and that's the behaviour.

</comment></comment></comment><comment><USER20> Kind of makes sense. I do not know anyone actually using it on Linux, there are much better alternatives. Only problematic part was PDF Forms, now probably obsolete.

</comment><comment><USER21> Wasn't it stuck at version 9 (or 10?) anyways, when all the other systems got 11 already?

</comment><comment><USER22> The latest version that Adobe released for Linux and Unix was Adobe Reader 9. Adobe stopped supporting it on 6/26/2013\. It's disappointing that they kept providing downloads of unsupported software until now. Red Hat put out an advisory in last year that said:

"Red Hat advises users to reconsider further use of Adobe Reader for Linux, as it may contain known, unpatched security issues... Red Hat will no longer provide security updates to these packages and recommends that customers not use this application on Red Hat Enterprise Linux effective immediately."

[http://www.redhat.com/archives/rhsa- announce/2013-October/ms...](http://www.redhat.com/archives/rhsa- announce/2013-October/msg00003.html)

</comment><comment><USER23> Pity, but it's a little surprise. They couldn't compile even their soft for Linux@x86_64 for several years.

<comment><USER24> If that is the crieria, then should we expect Google to drop Chrome for the Mac? That's still 32 bit.

</comment></comment><comment><AUTHOR> I found these files on the net. Seems legit. (I said seems) [https://drive.google.com/folderview?id=0B0fHzt9sGi2kRzM4R1JV...](https://drive.google.com/folderview?id=0B0fHzt9sGi2kRzM4R1JVeER4Xzg&usp=drive_web)

</comment><comment><USER25> I simply run virtubox+windows under Linux for adobe-form/turbotax etc that are too hard to do under Linux anyways. Hard to be 100% Linux still, but I'm close to 99% I think.

</comment><comment><USER26> Beyond the pdf reader, what are the alternatives to the PDF format that can be shared with regular people and has the same qualities (widespread, wysiwyg, not editable, etc.) ?

<comment><USER27> Some of the qualities you described are not there in PDF so I'll just name a reasonable alternative.

HTML.

<comment><USER28> HTML is not WYSIWYG, and it's a pain in the butt to share an html document with specialty fonts, graphics, precise print layouts, etc in it.

</comment></comment></comment><comment><USER29> Oh crap.

I was relying on that software to play the embedded media in PDF files issued by my school.

Anyone have a mirror, because I recently wiped my computer...

</comment><comment><USER30> Good riddance! I stopped using it many years ago. The default PDF reader provided by the distro is good enough for my needs.

</comment><comment><USER31> zathura is lightweight PDF reader with vim-like keybindings and vimperator/vimium style navigation.

</comment><comment><USER32> Does the current Windows version work using Wine?

</comment><comment><USER12> The people that use Linux are generally OSS enthusiasts who are not going to be willing to install a privative software. They problably didn't have that many users, and was not worth maintaining it.</comment>


MDwiki – Markdown based wiki done 100% on the client via JavaScript - hilbert- http://dynalon.github.io/mdwiki/#!index.md

<comment><AUTHOR> TLDR; Not actually a wiki. This is a nice front end js component that live autocompiles markdown into HTML.

IMHO to be a wiki it would need to manage user editing and version control.

<comment><USER2> Author of MDwiki here. Versioning and editing is indeed intended to be done and handled through git. Pull requests are prefered method for collaboration. Another way is to place the wiki on a Dropbox shared public folder and share the folder with your collaborators. Hosting can be done through Dropbox as well.

<comment><USER3> In that case, I just came up with some awesome new minimalist wiki software: it's called 'plain text files in a git repository'.

</comment></comment></comment><comment><USER4> Wikis are editable live, usually by anybody; but I cannot see a way to edit any of these projects that use MDwiki. So if that is the case, this isn't a wiki project, and why is it called one?

<comment><USER5> A pull request would edit a page, I think.

<comment><USER6> But that doesn't make it a wiki.

<comment><USER7> Au contraire, I think GitHub's editing features are actually close enough to make a wiki.

Though... you might as well just use GitHub's Wiki...

</comment></comment></comment></comment><comment><USER8> What.. a "wiki" that isn't shared? (I can see it could be made to have server component, I like the idea of doing all rendering on client-side, why not?!) The rendering is unfortunately glitchy (FF30; sometimes the CSS seems to drop during load/link clicks) and the stack of various libraries used is so deep that it may well be difficult to find the cause? Sorry, that's presumptuous actually, but I sometimes wonder why small projects like this need this many libs:

        marked
        jQuery
        Bootstrap
        Bootswatch
        colorbox
        highlightjs

<comment><USER9> TiddlyWiki, the original self-contained wiki (and now nearly 10 years old), was (is?) often used for note-taking. All you need is a browser, point it at a file:/// URI and you could save your changes locally.

[http://tiddlywiki.com/](http://tiddlywiki.com/)

</comment></comment><comment><USER10> That's really cool! It reminded me of Ward Cunningham's Smallest Federated Wiki, which is mostly client-side too; although it normally uses sinatra, there's an arduino port and I seem to recall an experimental server implemented using only apache conf hacks too.

[https://github.com/WardCunningham/Smallest-Federated- Wiki](https://github.com/WardCunningham/Smallest-Federated-Wiki)

</comment><comment><USER11> If anyone wants a python implementation, I have recently found MarkWiki[0] to be quite excellent. It's simple to use - I deployed it within a small team, all familiar with markdown.

[0] : [http://pythonhosted.org/MarkWiki/](http://pythonhosted.org/MarkWiki/)

</comment><comment><USER12> This is similar to what we are building at UserDeck. We call it Guides and it is a knowledge base widget that embeds inline into any page of a website. It is all Javascript and customizable on the client side with layouts and components which have options which let you change things like a sidebar component to the right side instead of the left.

Any team member can collaborate and edit articles live on the site and we are considering adding wiki type functionality if people are interested.

You can learn more at [http://userdeck.com/guides](http://userdeck.com/guides).

</comment><comment><USER13> And how is the crawling of search bots handled? Does Google render this into HTML and interpret the hyperlinks and try to crawl deeper pages as well?

<comment><USER2> Crawling is an issue. But if you google for mdwiki, first result will be the projects website which IS crawled. I think this is undocumented by google, but they do fetch ajax content. But you can not do professional SEO with frontend- only solutions.

</comment></comment><comment><USER14> When I reload the page in Firefox 30, I first see the non-styled content, which is a bit jarring.

</comment><comment><USER15> AFAICT, this entirely runs on the client. The server just serves some static web pages. Presumably, if you save the static HTML / js / css files onto your laptop, you could use the wiki when you're offline.

</comment><comment><USER16> I like JS and all that but having to wait for the css to load is not great UX.

</comment><comment><USER17> This is interesting. It would allow me to make quick work of all the markdown files I have to get them alive. +1.

</comment><comment><USER18> Also check out [http://slimwiki.com](http://slimwiki.com)

</comment><comment><USER19> is it possible to get pretty URLs? that might be the one thing that might stop me from using this -- this is exactly what i have been looking for!</comment>


Show HN: Unicorn Valley-Platform for crowdsourcing satirical/dumb startup ideas - <AUTHOR> https://unicornvalley.xyz <comment><USER2> Reminds me of the half bakery. That was a fun site. [https://www.halfbakery.com](https://www.halfbakery.com)

</comment><comment><USER3> Kudos! It's not so often I manage to spot Goat counter in the wild

</comment><comment><USER4> Long form satire is really a dying trade.

</comment><comment><USER5> This is like if Hackernews and TheOnion had a baby. I love it.</comment>


Digital Asset and ISDA Introduce Tool to Help Drive Adoption of ISDA CDM - <AUTHOR> https://medium.com/daml-driven/the-isda-cdm-much-more-than-just-a-standard-for-the-derivatives-lifecycle-71c367373743 <comment><AUTHOR> The CDM reference implementation in DAML discussed in this blog post is open source: [https://github.com/digital-asset/lib-cdm-event- specification...](https://github.com/digital-asset/lib-cdm-event- specification-module)

Digital Asset has also open sourced a complete example of a swaps application in DAML using the CDM: [https://github.com/digital-asset/ex-cdm- swaps](https://github.com/digital-asset/ex-cdm-swaps)

Both repos are licensed under Apache 2.0</comment>


Ask HN: How to obtain the FB activity logs of a missing person? - <AUTHOR> 	A person I know has gone missing, and the last bit of information about him is a Facebook post that he posted 3 days after any of his relatives have heard of him. It has been more than 15 days since he has gone missing, and his relatives came up with the idea to inspect his activity logs with the hope to locate where he was, and whether he has logged in on Facebook again. Now, this sounded like a scenario that has happened before, and I googled for some information. It turns out that only a law enforcement officer can request such activity logs: https://www.facebook.com/help/174766325911479?ref=u2u. I would want to know if there is anything else that could help to speed this up. <comment><USER2> Preface: Throughout these steps, it is in your best interest to be polite, calm, brief and to the point, and respectful of everyone's time. Genuinely thank everyone for their time and give your contact info to anyone who will take it.

1\. File a missing person's report.

2.Wait 1-2 days and politely request the contact details for the assigned detective.

3\. Politely call the assigned detective and briefly request they subpoena Facebook for activity logs.

</comment><comment><USER3> I doubt that Facebook would ever turn over his information to you or his family. Your best bet is probably to file a missing person report with the police.

<comment><USER4> I would be pretty shocked. Imagine if Facebook did have a process for handling these kinds of requests directly from friends/family/romantic partners rather than working with law enforcement. This could be an excellent way for abusive partners/parents to track down runaways and bring them back under their control.

</comment></comment><comment><USER5> Unless you're law enforcement, good luck. I hope you find who you're looking for, through other means.

</comment><comment><USER6> I would imagine law enforcement / police should be able to request this if the person has been missing a certain amount of time. But I personally feel it would be better to only let the police request it, rather than personal individuals as it would raise a lot of privacy questions.

</comment><comment><USER7> Report to law enforcement.</comment>


Guy Who Got a C on Constitutional-Amendment Paper Gets Constitution Amended - <AUTHOR> https://loweringthebar.net/2017/03/guy-who-got-a-c-on-amendment.html <comment><USER2> "Under Article Five, an amendment can be proposed and sent to the states by a two-thirds majority of both houses of Congress, or by a national convention if three-fourths of the states call for one. There's never been a convention for that purpose, and my God, what a nightmare that would probably become."

Well; [https://www.conventionofstates.com/nu](https://www.conventionofstates.com/nu)

</comment><comment><USER3> and got an A+

[https://loweringthebar.net/2017/03/guy-who-got-a-c-on- amendm...](https://loweringthebar.net/2017/03/guy-who-got-a-c-on- amendment.html)

"In light of the student's heroic efforts to prove the professor and T.A. wrong in their assessment of his term paper, Mr Watson deserves A+"

</comment><comment><USER4> The article isn't as clear on this as it could be, but this is not a recent news article: the C was gotten in 1982, and the amendment was ratified in 1992 (and had in fact been sitting around since _1789_ ). An impressive feat nevertheless.

<comment><USER5> But the part about a book author calling the professor who gave the C and getting her to change the grade just happened. Look at the date on her form to amend the grade: March 1, 2017:

[https://i1.wp.com/loweringthebar.net/wp- content/uploads/2017...](https://i1.wp.com/loweringthebar.net/wp- content/uploads/2017/03/watson-form.jpg)

Awesome story. :)</comment></comment>


What's the difference between 127.0.0.1 and 0.0.0.0? - <AUTHOR> http://superuser.com/questions/949428/whats-the-difference-between-127-0-0-1-and-0-0-0-0

<comment><USER2> only one mention of INADDR_ANY</comment>


Google-born startup thinks its time for a ground-source heat pump renaissance - <AUTHOR> https://arstechnica.com/information-technology/2017/08/google-born-startup-thinks-its-time-for-a-ground-source-heat-pump-renaissance/ <comment><USER2> So if I get this correctly, the 'renaissance' here is merely drilling smaller holes for the pipes to go in, so the cost of hauling the dug up debris is lowered. Anyone here know what the cost savings are as I can't image these are big to begin with.

<comment><USER3> Also it is not unusual to use a 4 inches (100 mm) down the hole hammer when drilling vertical holes for geological prospection/sampling.

People which drill water wells use normally bigger diameters, such as 6 inches (150 mm) or even bigger, their drilling rigs are huge truck mounted rigs, but there are a number of much smaller machines suitable for the task of drilling a 100 mm vertical hole up to 120-150 m or so.

The "resonance sonic drill heads to liquify the earth in the drill path" maybe are the "new thing", but it actually dates back to the '80's:

[http://www.cpeo.org/techtree/ttdescript/soncdrl.htm](http://www.cpeo.org/techtree/ttdescript/soncdrl.htm)

Like more traditional temporary casing it is installed and removed afterwards as actually the casing is made by the actual drilling pipes, of course it is much faster (on the "right" terrains) than having to deal with two pipes (the drilling one and the casing).

The difference in cost of hauling the debris is nothing.

Let's make a 100 m deep hole 10m mm in diamater:

0,05^2x355/113x100=0,78 cubic meters

the same hole but 150 mm in diameter:

0.075^2x355/113x100=1,77 cubic meters

Even if you multiply both by a factor of 2 (terrain "grows" when excavated and the actual hole is bigger than the size of the drill) the difference is between a half empty small truck and a filled up small truck.

If I have to give it a "universal" cost it cannot be more than 100 US$ per cubic meter or 200 US$ for each drilled hole, whichever comes first.

I.e. 0.5 to 1% of the given estimated 20,000 US$ per installation.</comment></comment>


Another High Speed Trading Error: BATS Global Markets - <AUTHOR> http://online.wsj.com/article/SB10001424127887324581504578233462967563782.html

<comment><USER2> Paywall. Available to WSJ subscribers only.</comment>


Chrome's Integration With Google Search - <AUTHOR> http://googlesystem.blogspot.com/2013/03/chromes-integration-with-google-search.html

<comment><USER2> A note: disabling the 'Instant extended API' in chrome://flags gives you the old new tab page back.

(I can see the reasoning, but personally think it's ugly and a waste of space. Then again, I never liked having Google as my homepage to begin with)

</comment><comment><AUTHOR> Google spent this much time on trying to get dumb users to learn to search from the omnibox? I think there is a solid opportunity to target highly skilled users with high performance machines. You can use more shortcut keys for things, and you don't have slow down from casual/confused users

</comment><comment><USER3> I don't understand the purpose of this change. If Chrome was a new product, I'd understand it as it'd probably mean that Google was trying to get people to use Omnibox, but don't people already know that the address bar is also the search bar? This is just a waste of space.</comment>


Show HN: Free Math, an offline React app for managing digital math homework - <AUTHOR> http://freemathapp.org/ <comment> nv-vn (Slightly off-topic) It's really sad to me that as of yet there is nothing to compete with paper and a pencil for math. I've used probably 10 different programs/websites, lots of stand-alone software, LaTeX, drawing programs on tablets, etc. for this during my time as a student. All of it feels poorly put together because none of it solves any new problems. Drawing on a tablet is a worse imitation of drawing on paper. TeX is just unwieldy for anything other than writing down a final answer. Even the tools that are supposed to help automate stuff almost always fail to do so. To be clear, I think there is a lot of room for improvement within the next few years, especially when it comes to touch-screen interaction and similar ideas. I'm just hoping someone comes along and invents a decent product that feels just as intuitive as drawing diagrams and writing equations that utilizes the power of the computer strapped to it effectively (i.e. not just attempting to translate and simplify my drawings to text).

<comment><USER2> For me, expressing math as code in a high-level language like R is _way_ more intuitive, and faster to read/write/extend/verify than formulae.

This said, my context is always data-analysis/modeling. I've never felt intimidated by code, though I spent many years being intimidated by certain formulae. I'm fairly certain that I'd have pursued math to a much higher level in school if the symbolic expressions were pseudo code I could mess with, but this may just be my odd learning style.

<comment><USER3> What proportion of the range of mathematical notation that professional mathematicians use would you estimate you're able to express in R?

<comment><USER2> In R, an inadequate one, but that's not R's goal.

I'm merely saying that in terms of symbolic representation of math, I've personally found code or pseudo-code the fastest to understand (but I'm not a professional mathematician!).

</comment></comment></comment></comment><comment><USER4> What do you feel is the core problem you are trying to solve? And any concerns about whether the effectiveness of student learning might be affected by using an electronic tool instead of pen and paper? [1] [https://www.npr.org/2016/04/17/474525392/attention- students-...](https://www.npr.org/2016/04/17/474525392/attention-students-put- your-laptops-away)

<comment><AUTHOR> For better or for worse, tech is being forced into classrooms by textbook companies. At least this project emphasizes students working on good old complete assignments, rather than tiny bite-sized activities. It is also free, rather than $100 per student per year/semester.

Computers are okay at deciding if an answer is correct, but they are not good tutors. Teachers can use Free Math to find the gems in their students work that demonstrate their misunderstanding. Currently there is no way for them to process all of the data and work produced by their students every day and have access to this granularity of information.

I considered having an app that would take pictures of student work, but OCR just seemed unrealistic for math. Bad handwriting and symbol ambiguity are almost guaranteed to make any automated transcription of math work buggy. Unlike with natural language, which you can produce on your approximate mobile keyboard, there is no way to auto-correct a symbol or number based on the context.

</comment></comment><comment><USER5> Hi, I'm an investor from China. Instead of forcing students to use cumbersome computerized inputs for equations, we are seeing multiple approaches to revolutionalize how math homework is being marked in China, including professional scanners in schools, taking photos using apps, writing equations on iPads and using digital pens with special paper. The are multiple hard parts for this process, such as OCR for complex symbols, solving the problem itself using deep learning and theorem provers, and checking if the students work per line is correct. I haven't seen anything like this in the US, other than a few work in automatic solving the SAT exam(geosolver?).

<comment><USER6> See Gradescope ([https://gradescope.com/pricing](https://gradescope.com/pricing)) and Mathpix ([https://mathpix.com/](https://mathpix.com/)).

</comment></comment><comment><USER7> I'm sceptical that this will improve the classroom climate for that I'd have to be developed with actual teachers and students. Digitalization just for the sake of it is considered harmful.

Also I'd be wary to trust the similarity metric, IMO it is best to assume good faith until you have evidence of cheating.

Anyway I think this can turn out great, like other have said, if it gets some polishing here and there.

<comment><AUTHOR> I also want to assume good faith, but some people in education are far more skeptical. I have been in meetings where those in charge or enforcing policy said things like "officially we have to have logins for each student", when a teachers said they preferred a simpler platform with a single quiz URL and students putting in their own names to identify their submissions.

I think one of the major problems with other products, is that they come out swinging with an accusation that all students cheat. Most tools these days have unique problems per students, which can make it harder to go over an assignment, because no one did the same problems.

I know there are varying opinions for what constitutes technology for improvement of a process, vs tech for the sake of tech. I think the world needs a digital way to represent symbolic math, it's one of the last complex processes done daily by millions that is locked out of a computer. Making something digital allows you to have undo/redo, and could eventually lead to a lot of interesting productivity enhancements. Nearly no one writes large amounts of text with pen anymore, because there is just so much more flexibility with a word processor.

One of the few things that forces people back to pen and paper is if part of what they need to write involve math formulas, because the current editors that include equation editing aren't fast enough. This platform isn't currently designed for mixing text and math, but it isn't too hard to add soon.

</comment></comment><comment><USER8> I think this is great! The offline first approach will clearly help to adopt this in a case when there is not central class management system in school.

<comment><AUTHOR> Thanks! Definitely one of the hardest things to do getting products into a school is having them approved for support by IT. This doesn't apply to websites, unless they need to manage logins. While there would be some workflow optimizations with a fully managed web app, most districts wouldn't want to have a special gradebook for a single subject/department. This also simplifies development for me early on, so I can focus on the rest of the user experience without a bunch of dev ops work to keep the service up.

</comment></comment><comment><USER9> Nice project, a claver way of skipping repeat write of previous math step work and just do little edit for the NEXT step in the Math homework .

github [https://github.com/jaltekruse/Free- Math](https://github.com/jaltekruse/Free-Math)

On a different note: I think for grading purposes of student math home work which is done on a paper, Deep Learning neural network programs will be advanced enough in 5 years that is by 2023 \- we will have a $200 flatbed scanner in every class room, as student finish his school work/home work, she can put the papers on scanner, it will sent scanned image to school server which is running Deep Learning software which Grades and home work and record scores in Database for teacher to view .

<comment><AUTHOR> I think this might be a way that such a project could be accelerated. Machine learning is good, but math is extremely ambiguous. Symbols are re-used and their orientation relative to other symbols changes their meaning. Some problems want you to simplify, others want you to expand something. This project at least removes symbol ambiguity in written work.

Even if you could make a computer understand how to solve a bunch of problems, I'm not certain that blind machine learning would produce a good feedback system for getting students back on course when they misunderstand something. They could probably find some likely candidates where students may have made a mistake, but I don't think anyone has tech anywhere near this right now.

</comment></comment><comment><USER10> Very cool idea. It's so much better to see the steps of the solution rather than just ask for the final answer.

With a little polishing, this could be better/faster than solving homework on paper!

It would be really interesting to somehow connect the homework notebook with other "homework tools" like [http://live.sympy.org/](http://live.sympy.org/) as calculator, or geogebra for geometry, or just a generic diagram editor for doing diagrams (a bit like the scratchpad in khan academy exercises).

<comment><AUTHOR> I totally think this would be a good container format for these various interactive tools. I think one of the reasons why they are not daily tools for many classes is that so much of math is symbolic. So far symbolic math has been confined to paper, even if a district decides to pay $100 per student per year for access to one of the existing services that will nicely collect your students final answers and machine grade them, students still do their work on paper, and the software is oblivious to it.

On tools like Geogebra, I think we need more interactive tools, but they need to exist alongside the symbolic work that everyone needs to do in most of their classes. Managing a classroom full of students working on computers (which can be distracting), is hard to justify if it is only displaying supplemental material and you also need to transition to "normal homework time".

I definitely need to add a generic diagram editor to make this useful for classes like physics.

</comment></comment><comment><USER11> I wanted to take a look at the source code, but [https://github.com/jaltekruse/Free-Math](https://github.com/jaltekruse/Free- Math) is giving a 404.

<comment><AUTHOR> Sorry, I forgot to mark the repo as public. Should be fixed now.

The project is a bit messy, I still need to set up proper dependency management and a build system. For now the app all lives in the index.html file.

</comment></comment><comment><USER12> Looks great. Aside from ideation and execution, presentation was great too.

<comment><AUTHOR> Thank you!</comment></comment>


Ask HN: What do you think of hiring for potential (in engineering)? - <AUTHOR> What are your thoughts and/or experience with hiring people for what they could potentially become with the right environment and mentorship? <comment><USER2> We hired a guy who had been out of programming for ten years. We didn't know what we would get. Either he'd be decent to good after a ramp-up time, or there was a reason why he had been out of programming for ten years. So we "hired" him on a three month contract-to-hire, at a discounted rate. He worked out, and we hired him full time at a real salary.

<comment><AUTHOR> What made you take the risk, if I may ask?

<comment><USER2> Well, we needed someone, and we were having trouble finding talent. And he did all right in interviews. But it wasn't that much of a risk. If he turned out to be a total loser on the job, all we were out was three months salary at the reduced rate.

<comment><AUTHOR> Makes sense, that's a reasonable risk to take.</comment></comment></comment></comment>


Selling Airbnb host addresses to hotels and landlords - <AUTHOR> Am building a service that harvests Airbnb listings and identifies the address of apartments being rented out by hosts. I then want to package the information in a saas application allowing hotels to see Airbnb rentals around their hotel. This will give them the ability to see how big is the impact surrounding their hotels and an opportunity to act legally against the landlords and hopefully pressuring them to stop their tenant from further renting out their apartments. It can also help landlords by guiding them to terminate leases for those tenant or asking a cut of the revenue from their Airbnb rentals.
What do you think about me product HN? How do I go about pricing my product?
note: I am neither crawling or scraping Airbnb's listings, just connecting patterns pragmatically to identify hosts addresses. <comment><USER2> I think you'll find this is against Airbnb's Terms of Service on a few fronts, so be wary of that. "...you may not and you agree that you will not: \- use manual or automated software, devices, scripts, robots or other means or processes to access, "scrape," "crawl" or "spider" any web pages or other services contained in the Site, Application, Services or Collective Content;"

There's quite a few other clauses that you'll be breaching, so it might pay to have a read: [https://www.airbnb.co.nz/terms](https://www.airbnb.co.nz/terms)

<comment><AUTHOR> Every major site has such clause. It's a matter of how careful and aware your scripts are.

<comment><USER2> I'm not saying you shouldn't do it, nor that you can't. _Personally_ I think it's a terrible idea and bordering on evil, but that's neither here nor there.

Just be aware that if people find out what you're doing, it probably won't be looked at very fondly - legally or morally.

<comment><AUTHOR> morally? Seriously. Step back a little and look at it from a landlords perspective. Airbnb can facilitate lease violations and that's okay, but helping Landlords identify lease violations is morally wrong?

<comment><USER2> I don't disagree that the situation sucks for landlords if their tenant breaches the tenancy agreement and uses Airbnb as a tool for sub-letting. This of course also places the tenant in breach of Airbnb's TOS too.

But you're now suggesting that this injustice to landlords justifies harvesting Airbnb's user's personal information and then selling it? That's morally and legally questionable any way you look at it.

<comment><USER3> Seriously? the information isn't that personal if it's publicly listed on AirBnB...

</comment></comment></comment></comment></comment></comment><comment><USER4> Why the fuck would you want to help corporations crush the small guy?

<comment><USER5> Airbnb - $20B* Hilton - $30B Marriott - $22B Choice (Holiday Inn, Best Western, etc) - $3.4B

* [http://www.bloomberg.com/news/articles/2015-03-01/airbnb-sai...](http://www.bloomberg.com/news/articles/2015-03-01/airbnb-said-to-be-raising-funding-at-20-billion-valuation)

They aren't really the "small guy" anymore.

<comment><USER4> The Airbnb hosts are the small guys I was referring to. Ratting them out to their landlord? Selling their contact info to hotels? That's some dark shit and I hope it fails spectacularly.

<comment><USER6> Though I have never tried it myself, I know numerous people who have done AirBnB "hosting." It has enabled them to afford trips and vacations they could otherwise never afford; their tenants have always been cool people who loved the experience and left the spaces in immaculate condition (I served as the "key man" many times).

Every AirBnB experience I've witnessed has been win=win; the absurdly unbelievably filthy rich landlords can go cry in their beds stuffed with money as far as I'm concerned.

<comment><USER7> Well, but why those don't go out and buy a flat they can rent in AirBnB instead of sub-renting someone else's? Most rental contracts explicitly forbid sub-renting _and_ I'm pretty sure these cool people don't pay taxes on the money they get from the short-term tenants.

This is a greeeeey area.

</comment></comment></comment></comment></comment><comment><USER8> Are you doing it to make money, or to right an injustice you perceive? Or some other reason?

</comment><comment><USER9> Another potential client category for such business intelligence is municipal planning departments. Around the country they are all scrambling to adjust to the changes in use.

</comment><comment><USER10> If you had a large-scale set of data of AirBnB listings that was reasonably accurate, that could be valuable to many people, for all sorts of reasons.

I'm slightly skeptical of some of your specific suggested markets, though. I would guess landlords are not likely to be a big market. The apartment and condo buildings that want to shut down AirBnB in their building already have a fairly easy time looking through nearby listings and identifying the ones in their building. The ones who aren't paying enough attention to do that will probably not be paying enough attention to find out that they can buy a list from you, either, unless you do a lot of marketing. And governments so far are going more the route of just trying to force AirBnB to hand over listings directly, instead of buying from a third party.

</comment><comment><USER11> I wonder if there is a use for an SaaS that spits out the license plate number for Uber drivers. Uh Oh, I think this time I may have stated something that deserves being banned. Evil is as evil does.

</comment><comment><USER12> > _Am building a service that harvests Airbnb listings and identifies the > address of apartments being rented out by hosts._

> _note: I am neither crawling or scraping Airbnb 's listings, just connecting > patterns pragmatically to identify hosts addresses._

Could you clarify?

<comment><AUTHOR> oops that's a typo. Am screen scraping some of the Host's basic information and then looking into other sites to find a pattern that identifies them. From there I look up their address.

</comment></comment><comment><USER13> I hope I'm not the only one here who thinks this is incredibly ANTI- entrepreneurial. I'll even go so far as to say this would be a really JERKY and EVIL thing to do.

Are you a hotel owner who has a grudge against the little guy who is trying to make some extra income?

What's your beef with Airbnb hosts?

And just because "every major site has such [sic] clause" doesn't mean you looking for the loophole is ethical.

As someone who hosts on Airbnb, the thought of this kind of action that would very likely harm MORE than those intended... it's evil.

I hope it falls flat.

<comment><USER14> > I hope I'm not the only one here who thinks this is incredibly ANTI- > entrepreneurial.

How is it anti-entrepreneurial? Seems like a perfectly entrepreneurial response to the market opportunity created by overlap of the AirBnB vs. hotel conflict with the AirBnB vs. existing law conflict.

> I'll even go so far as to say this would be a really JERKY and EVIL thing to > do.

Some people say that about the way that AirBnB and AirBnB hosts have openly flouted laws governing short-term rentals. Any disruptive entrepreneurial activity is going to "jerky and evil" from someone's perspective.

And, maybe it _is_ jerky and evil -- but that's not a category opposed to entrepreneurship. At best, its an orthogonal concern.

</comment></comment><comment><USER15> If obtained with consent, I for one will find this service valuable and will be willing to pay for it. All the best.

</comment><comment><USER16> Don't love the application, but the tech is interesting.

I work in the space - would be fun to talk further.

</comment><comment><USER17> Do you also link to local legislation and local enforcement agencies?

</comment><comment><USER18> snitchr.com ?</comment>


Facebook employee dies after apparent suicide at Menlo Park headquarters - <AUTHOR> https://techcrunch.com/2019/09/19/facebook-employee-dies-after-apparent-suicide-at-companys-menlo-park-headquarters/ <comment><USER2> That's terrible. I have heard of poor work conditions in their content review division where workers are subject to setting some terrible things</comment>


TSMC Announces 2x Reticle CoWoS for Next-Gen 5nm HPC Applications - <AUTHOR> https://fuse.wikichip.org/news/3377/tsmc-announces-2x-reticle-cowos-for-next-gen-5nm-hpc-applications/ <comment><USER2> Without reading through the links given in the article for some terminology, this read like the turboencabulator [1].

[1] [https://www.youtube.com/watch?v=MXW0bx_Ooq4](https://www.youtube.com/watch?v=MXW0bx_Ooq4)

</comment><comment><USER3> Very few mortals will ever see anything of use from it.

Most of that advancement will go to XXL sized chips for companies with too much money.

Its a big irony that reticle sizes became a competition point after so many years of them getting smaller.

Those interposers are dud pieces of silicon with just metal on them, and they can be easily done by decades old equipment with 200-300nm process. The problem is that even 2 decades old equipment don't use 1:1 masks anymore, so they are also limited by reticle sizes.

For all practical use cases, Intel's EMIB, and better organic interposers still have much more appeal

<comment><USER4> >> Those interposers are dud pieces of silicon with just metal on them, and they can be easily done

Worse is better in HW as well? [1]

[1] [https://www.dreamsongs.com/WorseIsBetter.html](https://www.dreamsongs.com/WorseIsBetter.html)

</comment></comment><comment><USER5> The primary advantage of something like this over doing multiple die on a normal organic package is the increased bump density, allowing for more I/O, but it doesn't really help you with power density at all.

It's not that hard to be power-limited at well below even single-reticle sizes, though, in which case this doesn't really help at all. I could see AMD moving to something like this for integrating HBM in a future epyc/threadripper part, where they might want to add a lot of not- particularly-power-hungry silicon.

</comment><comment><USER6> What is 2x Reticle CoWoS? Is this something like double patterning?

<comment><USER3> They can get you an interposer double the old size</comment></comment>


The Little Book of Semaphores - <AUTHOR> http://open.umn.edu/opentextbooks/BookDetail.aspx?bookId=83 <comment><USER2> The author Alan B. Downey has released quite a few free books:

Check out [http://www.greenteapress.com/](http://www.greenteapress.com/) including:

 _Think Python_ : [http://www.greenteapress.com/thinkpython/thinkpython.html](http://www.greenteapress.com/thinkpython/thinkpython.html)

 _Think Bayes_ : [http://www.greenteapress.com/thinkbayes/index.html](http://www.greenteapress.com/thinkbayes/index.html)

 _Think Complexity_ : [http://www.greenteapress.com/complexity/index.html](http://www.greenteapress.com/complexity/index.html)

 _Think Stats_ : [http://www.greenteapress.com/thinkstats/index.html](http://www.greenteapress.com/thinkstats/index.html)

<comment><USER3> You missed _Think OS_. Great intro to systems, definitely recommended for weekend reading!

Think OS: [http://greenteapress.com/thinkos/](http://greenteapress.com/thinkos/)

<comment><USER4> A great guy. More interesting readings on his website (research papers, etc.: [http://allendowney.com/](http://allendowney.com/)

</comment></comment></comment><comment><USER5> Yikes! I'm appalled by the one-sided justification for semaphores in this book. (2.3, "Why semaphores?")

Semaphores are actually a horrible primitive for building concurrency. I sometimes call them "the goto of synchronization", which is deliberately ironic since they are a gift to the world from the "goto considered harmful" thinker, Dijkstra.

Debugging a problem with semaphores is difficult because they have no useful state beyond their count. You don't know how a set of semaphores might have gotten into a given state. (Vaguely analogous to the the argument that in a spaghetti program with backward gotos, it's difficult to have an idea of how control arrived at a particular node in the program.)

For instance, when we (ab)use a semaphore to simulate a mutex, that semaphore does not actually track the ownership: who is locking it now? It can be signaled by any task at all, whereas a proper mutex can diagnose the fact that it is unlocked by its owner.

Semaphores most certainly do not _impose deliberate constraints that avoid programmers avoid errors_ , whatever that is supposed to mean, ouch!

When higher level primitives are correctly built on semaphores (condition variables, read-write locks, you name it), the solutions look like Rube Goldberg mousetraps. And that's before additional requirements are added like error checking, or handling priority inversion and whatnot.

Semaphores have one very good application and that is a situation in which a very fragile context (such as an interrupt service routine) needs to generate a wakeup signal. The semaphore signal operation can be made reentrant fairly easily. This is not only true in OS kernels. Note that in POSIX, for instance, the sem_post operation is noteworthy for being async-signal-safe, meaning that it can be called from a signal handler. By contrast, other things like pthread_cond_signal cannot be.

</comment><comment><USER6> Seems interesting. IME, This is one of the topics that people who didn't do CS (and even people who did) tend to struggle with and get tripped up on in practice. I think I'm going to get this book and if it's good, I'll probably be recommending it to some folks. Glad to see Dining Philosophers mentioned - it was one of my favorite problems in school and it's a great allegory for resource sharing problems.

</comment><comment><USER7> Interesting thing is, his place of work is not famous as compared to top US institutions (I am from outside US). But his educations says it

Ph.D. Computer Science, University of California at Berkeley, May 1997 . M.S. Civil Engineering, Massachusetts Institute of Technology, August 1990\. B.S. Civil Engineering, Massachusetts Institute of Technology, June 19 89

<comment><USER8> This is not at all unusual, and I would be careful about thinking it has any predictive power.

It's extremely difficult to become a professor, so tenured or tenure-track professors at mediocre (but decent) schools often have degrees from big-name places.

Also, Olin College isn't even mediocre, just small. From what I understand it's pretty selective.

</comment></comment><comment><USER9> Allen taught every single software class I took in college,its awesome to see his writing recognized on HN! We actually worked through LBoS during a software systems course this past spring semester, it was a great way to get introduced to the complexities of multithreaded programs.

</comment><comment><USER10> This book is a must read. Helped me a lot score high at the exams for my operating systems exam.

</comment><comment><USER11> Isn't it the same book?

[http://greenteapress.com/semaphores/](http://greenteapress.com/semaphores/)

<comment><USER12> Yes. The PDF link in the original article links to the same PDF on this page.

</comment></comment><comment><USER13> This is a _really_ nice book on concurrency. Clear, detailed and assuming very little knowledge on the part of the reader.

</comment><comment><USER7> The best I have seen about semaphores. I am using this in my course. It helped me to explain concepts simple and clear

</comment><comment><USER14> A great book which cleared a lot of my concepts about OS back in school. Re- read is due!

</comment><comment><USER15> I recognize the author, Downey. He's usually very clear in his explanations.

</comment><comment><USER16> Looks very nicely written.

</comment><comment><USER17> Thought it was a book about flags first, but this is waaaay better! :)</comment>


Makani's time as an "other bet" comes to an end - <AUTHOR> https://medium.com/makani-blog/a-long-and-windy-road-3d83b9b78328 <comment><USER3> Ever since Sundar, a McKinsey guy, took over, the writing was on the wall for all of the bets that Sergey and Larry engaged in. He just cares about the bottom line (as some would argue he should), and doesn't have a "passion" per se. He's more than happy to just keep the train rolling, and keep the perception of growth up by showing more ads and using dark patterns[1] to make users click on what they think are web links but are actually ads. Eventually the train will run out of steam, and then its on to the next gig.

[1] [https://news.ycombinator.com/item?id=22107823](https://news.ycombinator.com/item?id=22107823)

<comment><USER4> As a serial entrepreneur now Google employee, I think the bets have received too much funding. They seem like long term government research projects not scrappy startups trying to scale. Putting more rationality and business expectations is a good thing to determine the viability of some of the ideas.

Opinion my own, not Google's.

<comment><USER5> I'm sure this is true by the standard MBA tooling. But if everybody is using those tools, it leaves opportunities for people thinking differently. Amazon, for example, has been hoisting a giant middle finger to MBA dogma for years with their overinvestment, and Bezos seems to be doing fine by it.

Another way to think about it is that Google really should be doing long-term research, because only finding and monetizing a major breakthrough is going to make it so that they don't have all their eggs in one basket. A basket that will, like all baskets, eventually break.

A third way is that as long as Google is extracting monopoly rents, they should probably put some of that money into government-like things that could have broad societal benefit. Because if they keep trying to maximize quarterly profit, they'll burn up all the societal goodwill that insulates them from real regulation.

<comment><USER6> Google are doing a lot of long term research though. Huge investments in AI, search tech, big data, networking, the TPU stuff. Self driving cars. Contact lens screens. Head-mounted displays. Drones. The list goes on and on.

Makani was funded for 14 years! 14 years!! How many companies are willing to fund speculative research programmes in things unrelated to their core business for so many years? None, that I'm aware of.

Truth is Makani should have been shut down years ago. Government or corporate has nothing to do with it (that is, the same assessment would apply if it was funded by the government too). Their idea clearly wasn't competitive with the by now highly optimised wind turbine industry. It's not obvious why it ever was expected to be so.

<comment><USER5> You seem to be arguing with something I didn't say.

I definitely agree that Google should prune their portfolio using rigorous standards. I'm just saying that if one judges the whole effort by typical established-business standards, you're going to get typical results. Some things need more time to prove viability. Since Google a) will be around a long time, and b) is currently dependent on a single cash cow, they can (and should!) take long-term risks with long-term payoffs.

> It's not obvious why it ever was expected to be so.

This is a very bad way to look at long-term research. Or any novel venture, really. You want to be a pundit with a great track record on startups? Just say each one will fail. You'll be right 90% of the time with very little effort.

But it's even easier to wait until something fails and say, "It's not obvious why it was ever expected to work." Of course! If it were obvious that something was going to work, it wouldn't need to be done as a startup. And once it has actually failed, hindsight bias lets us paint it as an inevitable failure. E.g., if SpaceX had had less money and a couple more explosions, it could easily have gone under, and then all of its detractors could have done the "we told you it would never work" routine.

</comment></comment></comment></comment></comment><comment><USER7> As far as I know, Makani has never successfully demonstrated net positive power generation. They have designed an incredibly complex tethered- helicopter-flying-wing, and that is an impressive technological achievement.

But it's also a terrifying controls problem, and suffers from the same drawback as all the "flying car" startups: What goes up, must come down. Traditional wind turbines are a bit more predictable. The offshore flight test in August ended with a crash and the loss of the aircraft. I have to assume that no net power was generated during this test, or they would have mentioned it in the press release?

[https://medium.com/makani-blog/makanis-airborne-wind- power-s...](https://medium.com/makani-blog/makanis-airborne-wind-power-system- takes-flight-offshore-907fd4c9af86)

Makani's device is able to briefly generate power for a fraction of each crosswind loop it flies, but it has to draw power from the grid to push itself the rest of the way around the loop. This is neither useful as an energy source, nor cost competitive with a traditional wind turbine.

For offshore applications, there are much simpler competing projects to put traditional wind turbines on spar buoys or semi-submersible platforms, e.g. [http://www.principlepowerinc.com/en/windfloat](http://www.principlepowerinc.com/en/windfloat)

</comment><comment><USER8> Everybody that is involved in the wind power scene that I know was _super_ skeptical about Makani. Those are people that have been building wind power installations for decades. Criticisms ranged from complexity to zoning, land use, safety and efficiency compared to more traditional designs. Moonshots are great if you have an actual goal that is achievable and will give you an advantage if it succeeds. Keep in mind that the original 'moonshot' (going to the moon!) was a PR effort, not something that was meant to be sold, turn a profit or done on a large scale. It was simply a massive PR job to try to recover from the double hit of first satellite and first man in space victories the USSR scored over the USA. This whole project to me looked like a Google level version of Armadillo space, interesting but ultimately going nowhere. Shell may keep it alive as a PR item, they will need all the help they can get on that front but I really doubt it will ever be used in production anywhere in volumes that matter.

The easiest way to compare Makani to stationary wind installations out there generating power today is to look at the effective cross section of the rotors and to realize that a moving rotor consumes exactly the same amount of power in lift that it uses going forward. So that will cancel out across the loop leaving you with a bunch of small rotors vs a _much_ larger rotor sweeping an enormous surface. And launching it is one thing, bringing it back in in a storm is a completely different proposition.

A 12MW Makani installation would use much more land and would be much more fragile than a comparable regular HAWT.

</comment><comment><USER9> X seems a strange blend of overly ambitious and overly critical/ constraining (which is partly related to conception of what is "big" enough). It's also unnecessarily secretive and would benefit from being more open, especially in the energy and climate space.

A lot of interesting ideas get shot down quickly, which is not necessarily a bad thing.. but I'm not sure what the false positive vs. false negative rate is in this process. But for those ideas that develop, it seems like perfectly solid technologies that could form the premise of an interesting startup don't get out the door because they don't meet an internal bar of "worthiness". Maybe let the market and external funders decide that?

Their internal process is not intrinsically good or bad, but what's unfortunate is that they don't really publish. I know they're not looking to be Bell Labs, but if they think a lot of these ideas aren't going to pan out, but many person-years of research effort goes in, they really should share the learnings and lessons as opposed to locking it up internally. When these projects don't pass their internal bar for being commercially viable (which seems rather disconnected from what that bar would be if the idea/ tech stood on its own outside), it's basically like academic research. Truly is a shame that a lot of smart people working on interesting non-commercializable ideas don't get to share that. Others might pick up on it, if not now.. maybe a decade or two down the road.

<comment><USER10> Unpopular opinion from a former Googler (who never worked in X, but knew a lot of people who transfered over there):

In general, people in X get paid too much to make it "worth it" to innovate. Obviously there are exceptions, but I'd say there is a perverse incentive to string the funders (Google) along as long as possible. Line engineers are making $250K+ / year, managers are making $500K / year.

Innovation is kind of a "swing big and go home if you miss". But there's no incentive to "go home" if you have a comfortable lifestyle. You want to keep going and you can convince the management of that because you inherently know more about the tech than they do. It's an information assymetry problem.

I see a similar effect in non-X moonshots funded by Larry Page.

[https://www.forbes.com/sites/jeremybogaisky/2019/12/01/insid...](https://www.forbes.com/sites/jeremybogaisky/2019/12/01/inside- larry-pages-kitty-hawk-returned-deposits-battery-fires-boeing- cora/#1c2b5ea58ab4)

Basically there's an incentive for "demo-ware" and not real innovation.

I'm glad I worked at Google rather than say Tesla, because I was doing "non- moonshot" engineering work. Tesla is notoriously chaotic. I think Chris Lattner said Tesla had the highest turnover rate he'd ever seen.

But I actually think the idea of firing a lot of people makes sense if you're innovating. It should be chaotic and messy because the whole goal is inherently risky.

I used to work in video games and they also fired people all the time and paid them like crap. I made 3-4x at Google what I did in the video game industry. But honestly it makes sense because of the financial profile of the industry vs. Google's industry. Put bluntly: you're filtering for people who really love it and are doing something irrational to innovate hard tech or create a blockbuster game.

I'm sure a lot of people will bristle at this from the employee perspective, but having worked in both environments for many years, I can see how the compensation changes people's behavior. You might not realize it but it does.

<comment><USER11> > Put bluntly: you're filtering for people who really love it and are doing > something irrational to innovate hard tech or create a blockbuster game.

The irrational thing being working way below the market rate for someone with their skills/talents, right?

<comment><USER10> Yes, it should be a conscious choice. This dynamic exists in games, academia, Hollywood, stand-up comedy, the minor leagues hoping of most professional sports, etc. The great thing is that software people have a nice choice of fallback jobs, whereas it seems like people get trapped in academia and are prone to being abused because of their vulnerable situation.

When the employees no longer believe in the goal, they can quit, "cash in" and go work a more traditional job. But X removes that natural dynamic, hence the questionable results being achieved IMO.

</comment></comment></comment></comment><comment><USER12> They somehow managed to spend a bunch of pages and a lot of words, and still did not say what _exactly_ are they announcing and what will the outcome be.

Are they shutting down? Are they getting acquired by Shell? Something else?

<comment><USER13> My read is that Alphabet is selling the assets to Shell, and Shell is thinking about what to do with them.

<comment><USER8> It would be interesting to know how much it sold for. I'm guessing not a whole lot, is there a public filing where Google / Alphabet will have to disclose this?

<comment><USER13> Google would only have to disclose it if the loss is material, IIUC. I doubt it is on Google's scale.

</comment></comment></comment></comment><comment><USER14> This sounds like one of the typical Google X "problems" that's more or less a fun experiment with no real concrete sensible applications.

Can you make electricity with kites? Maybe. Probably. Should you? Probably not.

If you look at the Goole X website ([https://x.company/](https://x.company/)), the problem is stated thusly: "How can kites be used to generate electricity in unexpected places?"

Any sensible person's first reaction to that should be: Why would you want to do that in the first place?

You want to generate energy in "unexpected places"? Why? I think you want to generate energy in places that need energy, no?

And why would you want to constrain the problem to use kites? What about all other energy sources? Is kites the best one? The most economical? Or is it just some engineering porn stuff?

Other problems seem to suffer from the same nonsensical approach:

"How can beams of light support the rapidly growing global demand for data?" Uh, what?

"How can balloons deliver the Internet to rural and unconnected places?" Who cares? How can paper airplanes deliver the internet to urban places? That's just a thought experiment with no motivation.

Etc. etc.

<comment><USER15> You went too Far. Loon (the balloon project) has done real work which people are benefitting from, in rural and remote areas which cover 5b people. Also, their design ideas for inter-device communication are popping up in spaceX and other places.

The space-X inter-satellite communication is photonics: beams of light.

So thats two things you pontificated on, you don't actually understand.

Loon is not 'blah, who cares' -Loon is 'wow: this is working, lets get this deployed' joined to 'we can re-purpose your model in LEO sats'

Do you seriously think "rural and unconnected places" is a who cares response? Here's a hint: go read the iridium story. People (with money) care a LOT about these spaces.

<comment><USER14> I think you're missing the point.

The point isn't that they're not doing "real work" or that what they're building doesn't work at all.

The point is about the approach which consists in engineering a "hard problem" by adding unnecessary constraints/hypotheses to a real (although often ill- defined) problem, and then claiming it's a marvel of engineering when a half- functional, non-viable solution is completed.

It's the XY problem applied to startups. Instead of trying to solve the problem (energy, connectivity, etc.), they start from a given technology, and try to shoehorn it into a problem. That's bad design, and probably bad engineering in most cases.

<comment><USER16> Numerous companies in the airborne wind turbine market, Makani, Joby: [https://www.greentechmedia.com/articles/read/a-beginners- gui...](https://www.greentechmedia.com/articles/read/a-beginners-guide-to-the- airborne-wind-turbine-market)

Numerous proposals, including from Lockheed, for balloon satellites: [https://en.wikipedia.org/wiki/High- altitude_balloon#Geostati...](https://en.wikipedia.org/wiki/High- altitude_balloon#Geostationary_balloon_satellite)

These aren't just "because we can" frivolous projects, these approaches have serious advantages over others, such that many are racing to commercialize it.

<comment><USER8> I'll bet that plenty of these exist as copycat clubs that would have never been funded if Google had _not_ funded Makani. At least some of them seem to sidestep some of the most obvious problems.

</comment></comment></comment></comment></comment><comment><USER17> I submitted the ft story a couple hours ago.

[https://news.ycombinator.com/item?id=22361216](https://news.ycombinator.com/item?id=22361216)

In case you pay for ft and not Medium, like myself.

Direct link:

[https://www.ft.com/content/56582032-528e-11ea-8841-482eed003...](https://www.ft.com/content/56582032-528e-11ea-8841-482eed0038b1)

<comment><USER18> The FT story was much more readable and direct than the Medium post. Thanks!

</comment></comment><comment><USER19> Nuclear is the only feasible way to scale electricity to the globe at an affordable price, over the next few centuries. Wind and solar are great supplemental sources but they can't run a modern economy.

<comment><USER20> I agree with you, but it will never happen. I lamented with a few reasons why in this comment: [https://news.ycombinator.com/item?id=19167207](https://news.ycombinator.com/item?id=19167207)

The best we can do is get behind solar and wind and pray for a fusion breakthrough.

<comment><USER19> Good post. I don't share your pessimism but I get why you feel that way. I think people just need to be told by a good leader that there are real trade- offs with taking "the nuclear option" but we have to embrace it.

People accept trade-offs all the time. We understand some jets crash but we still don't give up air travel. We understand cars crash but we don't give up automobiles. I just think nuclear meltdown risk is overblown. If it happens four times a century, is that acceptable? I think it is. All things considered, how many people have died from nuclear meltdowns versus coal extraction?

</comment></comment></comment><comment><USER21> Does that mean they are shutting down? Too bad, it was an interesting company developing an interesting kite-based alternative to traditional wind turbines.

Although Alphabet apparently wasn't a great match, is Shell any better - <USER2> they really going to be an effective advocate for developing wind power as an effective competitor against their primary fossil fuel business?

<comment><USER22> Speculation: Perhaps they will eventually adorn offshore oil rigs. 600kw is not large, but could help supplement power systems offshore.

It looks good for their image and seems a good fit for local conditions. In particular rigs stand-alone, so less concern with tether coming down on someone else.

<comment><USER23> I'd imagine an oil rig is the least likely place on the planet to need complicated wind power. They flare off natural gas constantly, sticking a turbine (or indeed just a thermoelectric stack ) in there would be trivial.

</comment></comment></comment><comment><USER24> Google X aka the moonshot factory has existed for longer than the original Apollo program. Has it launched any successful products for Alphabet?

<comment><USER25> The Apollo program didn't exactly reach product-market fit either. It too got shutdown by price-conscious Congress.

Moonshots are inspirational, but sadly do not seem sustainable.

On the other hand, I wonder how many successful startups ex-X employees will have launched.

<comment><USER8> They worked just fine, they delivered the product that was required: a PR victory over the USSR which had stolen America's thunder in the space race.

<comment><USER25> So taking that analogy backward: who was Google's USSR that motivated them to start X?

Facebook?

<comment><USER8> No, more that they don't want to be seen as 'just' a monopolistic search/advertising company, plus diversification if done successfully can lead to risk reduction.

</comment></comment></comment></comment></comment><comment><USER26> Interesting how people measure these endeavours always in the context of their perceived end goal. Remember "shoot for the moon and if you come half way you still got pretty far"? This is exactly that.

Learning what you can't do is as important as to know what you can do. I'm happy that Alphabet is doing these long term research projects and bets. >5 years I think, apart from government, only oil & gas companies project that long term, but they know much better what they will 'find'. What Alphabet does it moves the academic needle cause we learn so much on the way.

Maybe they can do better in publishing the results, cause that is an alternative to just shareholder value: society value.</comment>