Could an Eye Doctor Diagnose Alzheimer's Before You Have Symptoms? - <AUTHOR> https://corporate.dukehealth.org/news-listing/could-eye-doctor-diagnose-alzheimer%E2%80%99s-you-have-symptoms <comment><USER2> Not mentioned is the problem with prions and eye examinations as a possible infection route:

[https://www.nih.gov/news-events/news-releases/eyes-cjd- patie...](https://www.nih.gov/news-events/news-releases/eyes-cjd-patients- show-evidence-prions)

</comment><comment><USER3> Definitely interested in this. I had my genome sequenced at 23andme and they say I am at a higher risk for early onset Alzheimer's (My parents and grandparents were/are fine) because I have the two mutations they test for.

Just last year I was diagnosed with glaucoma, at the ripe age of 32. So I go to the eye doctor somewhat regularly now. Wonder if this is something I can start keeping track of, for science, or something.

<comment><USER4> > sequenced at 23andme

Be careful. My wife, a geneticist, calls 23andme "for entertainment purposes only."

<comment><USER5> In this specific case, they do test for the ApoE gene which can you a 20x higher chance of getting Alzheimer's [https://en.wikipedia.org/wiki/Apolipoprotein_E#Alzheimer's_d...](https://en.wikipedia.org/wiki/Apolipoprotein_E#Alzheimer's_disease)

20x more is not a sure thing, but for a disease like Alzheimer's that is already pretty common (e.g. we're not talking about risk increasing from 0.01% to 0.2%) it's more meaningful than just for entertainment purposes.

I agree with your wife that for most people their 23andme results will be nothing more than entertainment, but there are a handful of truly meaningful things it can find.

</comment></comment></comment><comment><USER6> I've read that before there is tissue decay, which this test would be for, there's a preceeding biochemical phase: [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2819840/figure/...](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2819840/figure/F2/)

</comment><comment><USER7> The title is kinda wrong. Loss of blood vessel _is_ just yet another symptom.

<comment><USER8> Yes, however, finding an early symptom, particularly a decade early, would be an incredible find.

If we could detect pancreatic cancer early, for example, would could go from a 7% survival to 90% rate.

<comment><USER9> Can we not detect it early? Or do we just not run the tests?

Like if everyone got regular MRI scans (I know, expensive, but it's a hypothetical) could we do the same thing?

<comment><USER10> As far as I understand it, the area of the pancreas can often be difficult to detect cancer in- and particularly the area has a lot of space for metastasis.(I'm not a trained medical professional so if my words are contradicted by anyone who is, please ignore me entirely.)

I'm under the impression MRI scans have two main issues with them:

1\. A trained radiologist can still miss small tumors, and it is in fact quite easy to miss them. The body is complicated and all sort stuff of weirdnesses can occur that are not harmful.(eg. Benign tumors)

2\. It is possible that the discovery of a tumor doesn't mean cancer. This was a debate in breast cancer treatments- a lot of heartache and suffering can occur from a cancer scare and there has been existing controversy regarding early testing given this.

<comment><USER11> 3\. Radiation from breast cancer scans can cause the breast cancer in the first place:

[https://annals.org/aim/fullarticle/2480762/radiation- induced...](https://annals.org/aim/fullarticle/2480762/radiation-induced- breast-cancer-incidence-mortality-from-digital-mammography-screening)

<comment><USER12> That study is entirely based off simulation with the ultimate data being derived from survivors from Hiroshima and Nagasaki bonbings. We do not categorically know if there is a linear, no threshhold relationship between diagnostic radiation dose and cancer induction or if there is a threshhold dose below which radiation dose is "safe". We also don't know if low-level radiation is potentially beneficial (radiation Hormesis hypothesis).

That's a lot of words to say, take that paper with a huge grain of salt.

<comment><USER13> Was the linear-no-threshold model not basically disproven by a study on people who lived in buildings built with steel scavenged from the ruins of Hiroshima or Nagasaki and therefore in an environment with elevated radioactive background levels. They showed lower incidence of cancer if I remember correctly?

</comment></comment></comment></comment></comment></comment></comment><comment><USER14> Anyone in the field know if lattice degeneration would be considered 'loss of blood vessels in the retina' this study is looking for?

</comment><comment><USER15> Type 3 diabetes.

<comment><USER16> I'm not sure why you're being downvoted, other than perhaps the terseness of your response. There is research that hypothesizes that Alzheimer's is like diabetes in that it manifests itself as a dysfunction of insulin/glucose regulation.

<comment><USER17> Yes, the symptom described in the article is congruent with the diabetic theory because loss of small blood vessels is also a symptom of diabetes.</comment></comment></comment>


Bitcoin Now Worth $1B - <AUTHOR> http://codinginmysleep.com/one-billion-dollars/ <comment><USER2> Holy cow. It was worth $60 last time I checked (last time a story was discussed on HN). I'm not one usually to play Chicken Little, but doesn't a 50% rise in a matter of a week or two seem a bit unsettling? Unless adoption has risen similarly, which I doubt -- it's not like Amazon just announced they'll be accepting BTC.

Enjoy the run, speculators. But don't get greedy -- remember the tulips...

<comment><USER3> Cyprus just announced they would be taxing peoples bank accounts, the EU said that was a fair resolution for the banking crisis and other nations (greece, ireland, spain and italy) could see similar action to cope with the bank problems. Adoption as a currency has been ocurring for a while, reddit, mega, bitmit etc, adoption for investment has been ongoing, adoption out of fear of state controlled banks is another viable reasonf or adoption but harder to quantify. So there is a reason behind the price surge we are currently seeing but it is difficult to label because it is about individuals adopting it for use and not big corporations.

<comment><USER4> Maybe this is a misinformed question, but isn't the reason anyone is adopting it at all due to the fact they can later convert it back into actual currency?

<comment><USER5> "they can later convert it back into actual currency?"

Or final goods. Silk Road gives a final good endpoint for BTC

<comment><USER4> SR sure transits a large amount of btc, but what do you think the sellers are doing with the incoming bitcoins?

</comment></comment></comment></comment></comment><comment><USER6> Bitcoin definitely has potential. I doubt if it's in a bubble. Its a right mix of need and want for the global economy. It is also getting a lot of traction. As more enterprises adopt, the more its potential for disruption. [Disclaimer: I have bitcoins in my wallet]

<comment><USER7> The exchange rate in USD has quintupled since mid January. I can't see how this is _not_ a bubble.

<comment><USER8> Bitcoin is not some promise of a future product. It is already here, it works, it survived hackers, viruses, bugs in core software, it is not attacked by anyone (FinCEN guidelines suggest you can do whatever you want with BTC unless you exchange for cash), number of services and merchants accepting BTC grows. Why shouldn't it grow exponentially after the fact it is proven to work?

<comment><USER7> _Why should it grow exponentially after the fact it is proven to work?_

Fixed that for you. Those reasons are all much older than this sudden jump in value. Even if they weren't old, there's no way they're pumping the value of Bitcoin by 500%. If something's too good to be true, it probably is.

</comment></comment></comment></comment><comment><USER9> Anyone know if there is a good bitcoin futures/options market with good liquidity?

The vol on this asset class is out of this world and given that it's so new, pricing on these things must be so out of wack that it'll be good to exploit.

Only if there's a good futures exchange like Mt.Gox that's very very authoritative.

And also important for the bitcoin infrastructure, that way merchants will take bitcoins for less risk since they can hedge it against dollar or euro's. A big money potential out there. Some one please take the idea and build one so everyone can profit.

<comment><USER10> ICBIT has futures trading. <https://icbit.se/>

Bitfinex allows margin trading and lending. <https://bitfinex.com/>

<comment><USER9> Ty for link ICBIT futures has no liquidity.

Bitfinex's current best lending rate is at 200% APY, or 0.54%/day with maximum lend-out window of 7 days. Making most futures and options delta-hedging trades, even if ICBIT had liquidity probably not profitable.

To compare, current US broker margin rate is 1.8% APY or 0.004%/day. Will stick to regular exchanges until this is fixed or if there is an ETF for BTC in regular exchanges.

</comment></comment></comment><comment><USER11> I find bitcoin fascinating, but everyone who's bullish on it should understand the fundamental issue with its price stability, as pointed out by libertarian GMU economist Tyler Cowen (among others, presumably):

> It is a privately created fiat currency, bundled together with an anonymity > scheme for transactions. The anonymity scheme means there is some reason to > grant one-time seigniorage to the original currency issuers. Eventually the > anonymity scheme, in some form or another, will be available without the > fiat currency. At that point, or more likely before then, the fiat currency > will fall to near-zero in value. Hold it at your own risk. The original > issuers will have kept some of their initial gains.

[http://marginalrevolution.com/marginalrevolution/2011/04/the...](http://marginalrevolution.com/marginalrevolution/2011/04/the- economics-of-bitcoin.html)

Essentially, the value of a bitcoin is set by the value of all worldwide transactions desired which utilize bitcoin's advantages (anonymity, security from government intervention, etc) divided by the total number of bitcoins, which is capped. However, there is nothing to stop someone from starting a competitor (perhaps with some slight improvement) which duplicates all of bitcoin's functionality and essentially inflates away bitcoin's value. In fact, it might not be crazy to suppose governments would do this on purpose.

<comment><USER12> _which duplicates all of bitcoin's functionality and essentially inflates away bitcoin's value_

You mean like the Euro "inflates away" the USD, and vice versa?

Your idea doesn't make any sense.

</comment></comment><comment><USER13> That's a lot of money. What is this $1 billion being used for? Is this money just circulating for the sake of making more money, or is it being used to buy goods and services?

<comment><USER14> Most is probably being used for savings as the potential for it to increase in value over years is ridiculously high. If bitcoin succeeds in taking over fractions of global markets, which is is poised to certainly do because of its efficiencies, then the market cap will be hundreds of billions, and valued above several thousand dollars each.

But, bitcoins are being used in commerce too. New merchants added every day. I know of at least 6 brick and mortar businesses in Las Vegas alone that have sprung up recently.

<comment><USER4> The success of bitcoin in taking over fractions of global markets also depends on its learning curve, both in how to use them and how to keep your bitcoins safe(while still having access to them everywhere you need). Right now that's a pretty steep learning curve for non-technical folks.

</comment></comment></comment><comment><USER15> If you're trying to figure out how to buy bitcoins, check this out:

<http://howdoyoubuybitcoins.com/>

I recommend Bitfloor at the moment because they offer free capitolone360 transfers as well as cash deposits at local banks for only 1%.

If you're an accreted investor, check out <http://tradehill.com/>

<comment><USER16> I only see Bank of America options for deposits to Bitfloor. That entails filling out a deposit slip to Bitfloor's account at a local branch.

UPDATE: PEBCAK. That's for the default "cash" tab in the UI. There are also "wire" and "CapitalOne 360 P2P" tabs. Thanks for the tip!

<comment><USER15> Glad I could help you out!

</comment></comment></comment><comment><USER17> By design, the supply of new bitcoins is slowing down. If there continues to be utility for people to use bitcoins, and this usage is increasing, the value of an individual bitcoin vs. other currencies will increase (averaging out speculative action).

This pattern will very likely continue until an alternative is found. Perhaps the alternative will simply be for holders to return to national currencies, perhaps it will be to adopt a new bitcoin rival for transactions and value storage.

In the short-run, there may be speculation, bubbles, and pops. That gets the attention. But look beyond that. In the long-run, the bitcoin economy may indeed "grow" to many times its current "size".

<comment><USER18> Increasing value of currency promotes hoarding, when in fact, bit coin should be promoting spending. If everyone's intention is to buy and hold bit coins,they are useless as currency and become a speculative asset.

<comment><USER8> When everyone has hoarded some bitcoins they can trade them for goods any time they run out of fiat cash or fiat cash is stolen/diluted/frozen, or some arbitrary controls are imposed (e.g. sending money to another country is not easy or cheap). The instant mobility is the true value of "hoarded" bitcoins.

<comment><USER18> Everyone can't hoard bit coins, that's the point. Unless you are mining them, which is a small portion of the market I assume, you are buying them from another person. Ie someone else has decided to sell.

I get bit coin, I think it's interesting and useful as an alternative currency. But any hope that it is going to upend USD in any meaningful way is wasted. Dollars are far, far ahead in value, convenience and redeemability. And I don't see that changing anytime soon- at least not soon enough to get in on the speculation.

</comment></comment></comment></comment><comment><AUTHOR> The price chart looks a lot like the transaction volume chart, which is usually how I make my guesses as to whether we're in a bubble or not - increase in price without similar increase in usage = bubble. That said, it's anyone's call.

</comment><comment><USER19> There have been some strong signs of an inflection point in the last couple of weeks.

The FinCEN guidance was a major step forward for Bitcoin, allowing companies to start taking Bitcoin as a serious option.

For example, see this announcement today, from a company that processes payments for local governments. They plan to offer bitcoin acceptance to those governments for all sorts of online payments. You might soon be able to pay local taxes using bitcoin!

<http://www2.egovlink.com/press-release-bitcoin.cfm>

They directly state this is a result of FinCEN's statements. The floodgates may be opening.

<comment><USER20> You're not paying your taxes in bitcoin. You're paying an amount equal to your taxes, plus transaction fees, to the processor, who then converts your payment into the local currency and remits it to the government.

It's a subtle but important difference, because the use of non-local currencies in a transaction can trigger currency exchange gain/loss reporting requirements (in the US, at least).

</comment></comment><comment><USER20> I can't help but think of all the people (in the US) who will owe back taxes for 2013 for unreported foreign currency exchange gain...or (in the event Bitcoin crashes again) all the people who won't realize that they have foreign currency exchange losses that could reduce their other taxable income...

</comment><comment><USER21> I can't believe it's taken the HN community 3 years to take Bitcoin seriously. Makes me wonder about you guys.

<comment><USER5> its all fun and games until people really start cashing out.

<comment><USER8> Or until people realise that many around them already have BTC or ready to accept it as payment. Then who needs dollars?

<comment><USER18> I think you seriously underestimate the demand and use of dollars.

<comment><USER4> This. Wordpress, Reddit, even Expensify are but a glimmer of how much trade goes on with dollars in the world.

</comment></comment></comment></comment></comment><comment><USER22> Does anyone know when we can start buying again on coinbase? I'm still getting error messages.

</comment><comment><USER23> After a few weeks ago reading that BTC was at $45/btc and thinking this has to drop drastically soon enough only to see it now at $90... Not saying this growth isn't possible but it's not sustainable this early on, unless I'm wrong?

<comment><USER3> this chart shows the historic gold price over 36 years:

[http://goldprice.org/gold-price- history.html#36_year_gold_pr...](http://goldprice.org/gold-price- history.html#36_year_gold_price)

A similar thing is ocurring with bitcoin now however it is much easier to buy and store btc for the layman than it is for them to buy and store gold.

Adoption due to technology is also faster, essentially gold has been $1600 an ounce for a while now, BTC has a way to go before it stabilises but after $200 a coin we will see less daily fluctuations because a $10 change in price is actually only 5% of the overall value

</comment></comment><comment><USER24> There's an interesting spike in bitcoin value everyday when Europe wakes up. This does look like a bubble but at the end of the day, as long as the rest of the world currencies keep people nervous, bitcoin will gain wider adoption.

</comment><comment><USER25> A radio station was giving away bitcoins if you only liked their facebook page not too long ago... I gave mine to a friend :( This is madness!

</comment><comment><USER26> Come on Bitcoin-Central (or whoever) - hurry up and implement IBAN numbers so I can buy some in Europe!

<comment><USER27> I used Mt.Gox with SEPA transfer, it was a bit slow but otherwise worked flawlessly.

</comment></comment><comment><USER28> The Diamond Age. Good by nation state, it was a good run.

</comment><comment><USER29> This will be a fun ride until governments ban it.

<comment><USER30> That worked out so well when they banned copyright infringement.

<comment><USER4> That's completely different though. Banning the conversion of btc into real currency would be a huge problem for btc, who is going to accept btc in exchange for a product or service performed if they can't turn that btc into money to exchange with other individuals/companies? There needs to be a much wider acceptance of bitcoins by companies providing services/products over a longer period of time before banning the conversion(at least legitimate conversion) would no longer phase bitcoin.</comment></comment></comment>


Gevent: the Good, the Bad, the Ugly - <AUTHOR> http://code.mixpanel.com/gevent-the-good-the-bad-the-ugly/

<comment><USER2> Using a non-blocking server with Python does not really make sense since most libraries in Python are blocking by nature and gevent only solves the most simple conversions by monkey patching (and like the author notes this is very error prone).

If you want to use non-blocking in Python then using something like Twisted is an option since Twisted implements most things in an non-blocking way, but Twisted hasn't really gained that much traction in the many years of its existence.

So yes if you do a hello world benchmark then you get a 4x speed improvement, but if you do any library calls (such as doing a MySQL query) you will get decreased perfomance since the MySQL Python library is blocking (and most other libraries are blocking as well)...

<comment><USER3> The advantage here is the usage of Libevent which makes it only listen when a eventlet sends back a message. It's essentially using the same tech (event wise) as NGINX.

Because it's using event's it has not blocking IO. But is limited when the tasks are CPU bound

</comment></comment><comment><USER4> The current project I'm working on involves managing and launching a lot of http requests to different web service api's, and gevent really is the best thing since sliced bread.

Things like rate limiting (gevent can monkey patch time.sleep), error handling, and scaling to a large number of concurrent connections (see gevent.pool.Pool) have been added to my app with surprisingly little increase in code complexity. The fact that you write your code as if it was synchronous makes it so much easier to maintain. I don't have to find my way through callback spaghetti. I also find asynchronous much easier to grok than threading (and it's also more lightweight)

</comment><comment><USER5> This is very interesting, but I don't think comparing it to paste is valid. Paste is more meant as a development server, is it not?

<comment><USER6> No, not at all. Well, people do use it for development, but it's pretty much the recommended deployment option for several Python web frameworks, including Pylons.

<comment><USER7> Not true. Production deployments in Pylons are primarily done with mod_wsgi behind apache or in some cases uwsgi behind nginx.

Paste is generally not recommended outside of development purposes.

<comment><USER6> [http://pylonshq.com/docs/en/1.0/deployment/#deploying-the- ap...](http://pylonshq.com/docs/en/1.0/deployment/#deploying-the-application)

"There are lots of ways of deploying an application, one of which is to use the paster serve command which takes the configuration file that has already been used to setup the application and serves it on a local HTTP server _for production use_."

<comment><USER7> I've spent a good year developing with Pylons and this question of recommended production setup comes up about once every couple months in the official mailing list. Paste is considered by far the worst option in terms of performance, which is why most devs go with Apache/mod_wsgi. Nobody recommends Paste. Some (in my case) deployed with nginx/uwsgi.

<comment><USER6> The official docs recommend Paste. We've had apps in production running on Paste since 2007. At the time, neither mod_wsgi or uwsgi were around. Certainly it may not be the _best_ way to run in production, but it's not for development only.

</comment></comment></comment></comment></comment></comment><comment><USER8> I wonder how it might compare to Tornado (<http://www.tornadoweb.org/>)

<comment><USER9> I love Tornado personally, but I wanted to write synchronous code.

Eventlet (the project that Gevent forked from) allows you to write hubs while gevent only supports the libevent hub. So I made <http://github.com/vishnevskiy/greentornado> to allow Eventlet to run on Tornado's IOLoop. Been working for a while in production with no issues.

Would have made it for gevent though if I could since after reading the code of gevent and Eventlet I found that gevent's code base was much cleaner.

<comment><USER10> The creators of Tornado recommend writing synchronous code for everything except "long" operations for which you have no control. Examples of these include long polling and requests to third party services. Requests to your local database are not long operations. If these requests are long operations, then you have a latency problem with your application.

The Tornado people recommend running more instances of the application than CPUs to handle the short blocking requests to local databases and what not.

Although it depends on what your app does, my guess is that typical applications written with this philosophy are mostly synchronous code.

<comment><USER9> With eventlet and gevent you can write asynchronous that looks synchronous. Which is the point of greentornado.

That being said we still use synchronous calls to our databases.

</comment></comment></comment></comment><comment><USER11> how is this better than (the mature, well engineered) twisted?</comment>


PEP – An open source PDF editor for Mac - <AUTHOR> https://macpep.org/ <comment><USER2> I have a dream... that one day people will name their projects with names that don't exist on google yet.

If you search for PEP now you'll find python enhancement proposals, and the "Philippine Entertainment Portal" and the stock code for PepsiCo.

<comment><USER3> I wish that once people do name their project, they would assign it a 128-bit random number in lower case hex, and include that number on any web page that they would like people searching for their project to find.

That way once I know that say PEP the PDF editor exists and find its 128-bit number (let's say that is 379dd864b16eaca3ce94c15a6bdfcc73), at least I can subsequently toss a +379dd864b16eaca3ce94c15a6bdfcc73 on my searches to effectively let the search engine know I want PEP the PDF editor results rather than PEP the python enhancement results or PEP the entertainment portal results or PEP that refreshing beverage company stock symbol.

"xxd -l 16 -p /dev/urandom" is a handy way to get a 128-bit random hex number. A UUID generator works, too, although they usually include some punctuation you will need to delete and you might have to lower case their output.

<comment><USER4> > I wish that once people do name their project, they would assign it a > 128-bit random number in lower case hex

We already have something similar: URLs.

<comment><USER5> Except a URL only points to one resource. The idea here is that this identifier would exist on any resource related to PEP (maybe even in URLs).

<comment><USER6> >Except a URL only points to one resource

isn't that exactly what this is asking for though? A URL can by definition only point to one resource. So if you include that URL with every other reference to the project (in the app descriptions, blog posts about it, etc) then you always know you're talking about the same thing. It makes a lot more sense that any resource related to this PDF editor should include a link to "[https://macpep.org](https://macpep.org)" instead of including some random 128 character string. Any resource related to python peps should include a link to "[https://www.python.org/dev/peps/](https://www.python.org/dev/peps/)" (which all PEPs do, by virtue of having a url that's a subdirectory of the PEP index URL)

</comment></comment></comment></comment></comment><comment><USER7> A GUI app for manually crafting PDFs is one thing, but a _library_ instead would enable countless developers to create software capable of producing PDF deliverables as output, possibly improving the accessibility situation too.

I would gladly sponsor the development of a reliable library that allows to programmatically produce compliant, accessible tagged PDFs with arbitrary layout[0], correctly printable and viewable by mainstream software.

(Considering it is a difficult, yet to be solved problem, I'd have to know the qualities of the approach that distinguish said library from not-quite-capable attempts that already exist before I commit my personal funds.)

I would not mind if said library's developers release an entirely paid end- user GUI software based on it, as long as the library itself remains under active maintenance.

[0] Supporting commonly used paged media typesetting features such as headers, footers, page numbers, running headers.

<comment><USER8> Are you familiar with Prawn [1]? Perhaps I just haven't bumped up against its limitations yet, but in my experience it's exactly what you're asking for. Of course, it's in Ruby, which isn't to everyone's taste, but it's the best tool out there that I've found.

[1] [https://github.com/prawnpdf/prawn](https://github.com/prawnpdf/prawn)

<comment><USER7> Prawn was considered and IIRC unfortunately it has very limited styling support.

It looks like there are only commercial and quite expensive options for programmatic generation (Antenna House: XSL-FO, Prince: CSS). Apart from that, the one option that works appears to be Apache FOP. It's built on Java and uses XSL-FO, which is somewhat limited and seemingly on the way to becoming outdated.

<comment><USER9> [https://weasyprint.org/](https://weasyprint.org/) is quite nice, though has limited header/footer support (for now).

</comment></comment></comment></comment><comment><USER10> > its own PDF engine, built from scratch

Just be careful, many larger teams have taken on that PDF spec, and it has not ended well for them: [https://nvd.nist.gov/vuln/search/results?form_type=Basic&res...](https://nvd.nist.gov/vuln/search/results?form_type=Basic&results_type=overview&query=pdf&search_type=all)

and it seems to be one of the main actors in what are termed "polyglot" files: [https://truepolyglot.hackade.org/](https://truepolyglot.hackade.org/) (of which my favorite is: [https://news.ycombinator.com/item?id=18344778](https://news.ycombinator.com/item?id=18344778) _0x15 is a laser-projectable PDF that 's also a ZIP containing, among other things, another PDF that is also a Git repo of its own source code._ )

</comment><comment><USER11> Adding a roadmap with potential features would be nice. Otherwise one is actually asking for financing a personal pet project. A list of existing alternatives (incl MacOS Preview) could be added and an explanation why this project will be different (or ideally: better).

<comment><USER12> Isn't Preview limited to just annotations, or does it also do editing?

<comment><USER13> Aside from annotating, Preview can crop, reorder, rotate, delete, and insert pages in a PDF.

But at its core, it does not "non-destructively" edit the dictionaries and object graph of the original PDF. Instead, it replays the original PDF into a new PDF context.

</comment></comment></comment><comment><USER14> Hi, developer of a PDF scanning app for macOS (PDFScanner) here. I always toyed with the idea of developing a PDF engine from scratch but the spec scares me. Kudos for being that brave! Just curious: Why did you choose Objective-C for a new lib?

<comment><AUTHOR> Helllo, good question, and the answer is simple, I am more familiar with Objective-C and I get used to it.

<comment><USER15> Aren't you worried about Apple killing ObjC down the line?

<comment><USER16> Their whole UI is written in ObjC, they've got two decades of Mac apps in ObjC, and they wrote a whole new language to interface cleanly with ObjC but with nicer semantics, so I'm guessing ObjC isn't going anywhere.

But even if Apple does remove it, everything apart from the UI would still compile in GCC's ObjC compiler. The guts of this project is the PDF engine, not the UI, and that would still work. TeX is written in a language that pretty much only Knuth uses, and it's still very much working.

<comment><USER17> More than just their UI, fundamental parts of Apple's OSes are written in ObjC, including very new components like ARKit, CoreML, and the Metal API. Apple continues to write tons of new Objective-C code every day. Of course Swift is making inroads inside Apple, but Objective-C has to be well supported for a very long time to come.

I've been writing Objective-C for 15 years, and continue to do about 60-70% of my work in ObjC (the rest is mostly Swift). I'm not particularly worried about my code being unusable anytime soon. When Apple starts making a real effort to wholesale migrate away from ObjC, I will too.

<comment><USER15> What about Cocoa? You think it still makes sense to invest dev time in a Cocoa app?

<comment><USER17> That's a little more ambiguous. Until very recently I was primarily a Cocoa developer (took a full time iOS dev job a few months ago), and it still makes up a significant portion of my side work, so I'm biased. But right now, the alternatives are SwiftUI and UIKit/Catalyst. SwiftUI nicely integrates with AppKit/Cocoa, but anyway, it's in pretty rough shape on the Mac at the moment (see [https://news.ycombinator.com/item?id=24472063](https://news.ycombinator.com/item?id=24472063) for example). Catalyst is (IMO) basically garbage if your goal is to make a great Mac app. Its purpose is to allow easy porting from iOS to Mac, not to create truly good _Mac_ apps.

Obviously, the presence of these two technologies, and Apple's pushing them is evidence that Cocoa may be on its way out, but it's not deprecated, and is still officially the recommended way to build true Mac apps. Undoubtedly it's SwiftUI (not Catalyst) that will eventually displace it, but especially on the Mac, SwiftUI is not really ready for production yet.

<comment><USER15> I agree with all your points.

I considered getting into Cocoa dev but between the lack of resources and the probability that Apple will kill it in the not so distant future, it didn't make much sense.

Better wait a couple of years until the mud settles.

<comment><USER17> I think that's eminently reasonable. As someone with 15 years experience doing Cocoa dev, the intention to be a Mac dev indefinitely, and hundreds of thousands of lines of existing Cocoa and Cocoa Touch code, it's just going to be a slow transition. But there's no pressing reason to just stop writing any new Cocoa code (I literally wrote some since my last comment :-P). If I were starting now, I'd probably focus on SwiftUI with the assumption that it will be the way to start most new projects within the next few years.

</comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER18> For a second I thought this was a Python Enhancement Proposal.

<comment><USER19> Reminds me of a resolution of GDPR I had when I first heard of it.

'German Democratic People's Republic'

<comment><USER20> It would be the Federal Republic of Germany. Or the Democratic German Republic if you think of the east block.

</comment></comment></comment><comment><USER21> The UI for all of this guys apps is very strange...is this some sort of web- wrapper for OS X or custom views or what?

<comment><AUTHOR> Hi, i am the guy, and almost all view are custom views (native Cocoa/Objc), except that some of them (like in the About window) are WebView with HTML/CSS/Javascript.

</comment></comment><comment><USER22> The one problem I consistently have with PDF forms on the Mac is an inability to change the font size in text fields. My work even pays for me to have the professional Adobe suite and that specific functionality doesn't exist. If someone could solve this problem I would probably give them some money.

<comment><AUTHOR> Just noted down your requirement in my Apple Notes, I think I will take a look at it later while render and editing PDF forms.

These kinds of comments are what i am looking for, thank you.

</comment></comment><comment><USER23> Very cool!

I currently use adobe acrobat to make pdfs accessible ([http://www.w3.org/TR/WCAG20-TECHS/pdf](http://www.w3.org/TR/WCAG20-TECHS/pdf)).

Are you planning on building in accessibility tools?

</comment><comment><USER24> The PDF file format specification has 971 pages. [https://www.iso.org/standard/63534.html](https://www.iso.org/standard/63534.html)

<comment><AUTHOR> Just create a simple PDF example by using TextEdit's export function, and open the PDF with a plain text editor, you should be easy to figure out what's going on in PDF.

</comment></comment><comment><USER25> The apps by the same author are very, very interesting: [http://www.pixelegg.me](http://www.pixelegg.me)

</comment><comment><USER26> If someone knows something like this for Windows, I am currently offering a bounty:

[https://softwarerecs.stackexchange.com/questions/19011](https://softwarerecs.stackexchange.com/questions/19011)

I am willing to increase the bounty, but I only have 297 rep currently</comment>


Nasa Reaching New Heights - Whitehouse - <AUTHOR> http://www.whitehouse.gov/blog/2012/04/20/nasa-reaching-new-heights

<comment><AUTHOR> While the premise of the article is political, the reason I posted it was for this quote:

 _Krauthammer suggests that if China succeeds in putting astronauts on the Moon by 2025, as that country plans, they will have "overtaken" the United States. How absurd! Neil Armstrong and Buzz Aldrin walked on the Moon in 1969. How does China managing this feat fifty-six years later, if this happens, amount to "overtaking" us? Obviously, the United States could repeat its lunar feats of the 1960s and 1970s if that were the next most important thing to do in space exploration for the money. But it isn't! We may well return to the lunar surface again as one of many destinations in the future, but for now, our immediate, more scientifically rewarding goals include sending astronauts to an asteroid in the 2020s, and Mars in the mid-2030s. They bring scientific and technological challenges worthy of a great nation and a true world leader._

</comment><comment><USER2> I'll argue that Krauthammer is referring to energy devoted rather than past accomplishments. Should the Chinese return to the moon whilst we are convening panels to issue press releases about energy efficient NASA buildings, then indeed "overtaken" is correct. Bolden is just defending his sinecure and the aforementioned LEED office building.</comment>


Ask HN: How to go about asking for VC funding? - <AUTHOR> I have a prototype for a project that I would like to sell, and I was curious to the steps involved with getting a funding from angels and/or VCs.<p>I don't know that my project is big enough or interesting enough to get something like YC to fund it (though I do have a plan to monetize it), but I was curious to what people here would recommend in regards to getting seed money?  Do you just call up a firm to request a meeting?  Do I have to "know someone" and get a meeting that way? <comment><USER2> Apply to YC Startup School : [https://www.startupschool.org/](https://www.startupschool.org/)

You'll learn everything you need to know and have a chance to get funded and show your project to VC investors.</comment>


How Japan has almost eradicated gun crime - happy-go-lucky http://www.bbc.com/news/magazine-38365729 <comment><AUTHOR> Also a huge societal difference. In many ways, Japan can be isolationist and xenophobic. Controlling what comes in and out of the country is easier when it's completely surrounded by water too. Japan doesn't have a wide open border with Mexico. And it does irk me when they lump in suicides with "gun crime." 2/3 of the fatalities by firearm in the US are suicides. I think that's important to note. Japan has still maintained an unusually high suicide rate.</comment>


"Don't Try": The Philosophy of the Hardworking Charles Bukowski - <AUTHOR> http://www.openculture.com/2019/12/dont-try-the-philosophy-of-the-hardworking-charles-bukowski.html <comment><USER2> I just listened to an episode of The Happiness Podcast and it made it clear that obsession over goals and other people's validation kills our natural passion. I don't know about you, but passion is what I'm really after -- the kind of state where you get lost in your work and love what you do.

It may be easy to dismiss Bukowski's advice because his abrasive and cynical delivery style, but I think he has a point. Follow your interests, and try to forget about your ego and the rest of the world.

(However, at the same time, I think it's important to be consistent and develop good habits that will prevent you from quitting at the first roadblock.)

<comment><USER3> Sadly, a lot of people's interests (or their interests combined with their lack of ability, connections, etc) don't put enough food on the table.

"Forget about the rest of the world" isn't helpful if someone has a family to support, or even themselves. It is pretty privileged to think everyone can choose to only work in a field of their choosing... I don't know if many janitors have an 'interest' in cleaning toilets... they have an interest in supporting themselves.

I have always appreciated Mike Rowe's views on work and this idea... it is ok to just work to make money, and find meaning in other parts of your life.

<comment><USER4> Then you just have to decide what your primary goal is:

Is it to create a piece of (truly) original artistic expression?

Or is it to... put food on the table?

Both are perfectly valid. But -- as you are correct in noting -- quite different.

<comment><USER5> Everybody's primary goal is to put food on the table! You must be pretty insulated from the hard realities of life if you think people can simply treat survival as optional.

<comment><USER6> Putting food on the table for yourself is pretty damn easy. But if you want a house, kids, a wife, a nice car, etc, then it gets exponentially more difficult.

So, there is a choice available for creative people who don't wish to compromise: They can be fully into their work at the expense of the above cultural norms - perhaps if they are very successful in their niche they can have those things too, but there could be a very long or infinite period of their lives where this is not possible - that's the sacrifice.

I'm so sick of the 'I can't do XYZ because I have kids and a mortgage' talk - well maybe you should have thought about the long term ramifications of kids and a mortgage?

<comment><USER5> Okay, I agree with you. I guess "put food on the table" has a connotation of providing specifically for others and not just yourself, which I wasn't considering.

</comment></comment></comment></comment></comment></comment><comment><USER7> His quote (my favourite) may help understand this value: "If you're going to try, go all the way. Otherwise, don't even start. This could mean losing girlfriends, wives, relatives and maybe even your mind. It could mean not eating for three or four days. It could mean freezing on a park bench. It could mean jail. It could mean derision. It could mean mockery--isolation. Isolation is the gift. All the others are a test of your endurance, of how much you really want to do it. And, you'll do it, despite rejection and the worst odds. And it will be better than anything else you can imagine. If you're going to try, go all the way. There is no other feeling like that. You will be alone with the gods, and the nights will flame with fire. You will ride life straight to perfect laughter. It's the only good fight there is."

<comment><USER8> I was going to say "Do. Or do not. There is no try." but your quote was better!

</comment></comment><comment><USER9> I love Bukowski but "don't try, let it go, it will happen" doesn't make so much sense. He lived most of his life not too happy. Being successful after 50-60 doesn't justify suffering for something you want so much. Especially in today's world with high tech and fast-paced competitive environment, it is not as easy as before. It is much harder to sit in a motel room, drink all day and type so you might get published someday and make money. His lifestyle and approach really wouldn't (doesn't) work today.

<comment><USER10> >It is much harder to sit in a motel room, drink all day and type so you might get published someday and make money. His lifestyle and approach really wouldn't (doesn't) work today.

color me surprised; that kind of dedicated labor and isolationism sounds a lot like the startup world, to me.

pick the right specimen and they probably imbibe as much booze doing it, too.

</comment></comment><comment><USER11> Bukowskis work really struck me when I was in my twenties. I'm not sure it would now.

<comment> vincent-toups He really struck his girlfriends too, I hear.

<comment><USER4> _struck his girlfriends_

Multiple girlfriends? Repeatedly?

I'm aware of 2 incidents involving Linda King. With other incidents (involving which girlfriends) are you referring to?

I won't defend his behavior - but please, let's be accurate here.

<comment> vincent-toups Super important to be ultra careful about how many times this man hit a woman.

<comment><USER4> No, I just don't see the value in hyperbole -- or outright factual misrepresentation.

<comment><USER9> So, how many times is acceptable?

<comment><USER4> That's not the point.

</comment></comment></comment></comment></comment></comment></comment><comment><USER12> This is a lesson in what the Taoist call wu wei, which can approximately be described as inaction, effortless action or non-doing. In the context of the parent post, wu wei would imply unconflicted, spontaneous action wherein a person is not "trying" they are simply doing what comes natural to them.

</comment><comment><USER13> Pursuit of Wonder on youtube did a beautiful rendition of this[1].

That being said I'm not sure how well this holds up in modern world, especially when it comes to technology. A lot of initial barriars are really difficult to wrap your head around and often can only be overcome only by sheer will. That's the most important thing I've learned studying CS - sometimes you need to push through.

I'd really like to see some big data science on this. We all know the memes of Einsten flopping math or something but in reality most of the world changing actors seem to be quite predetermined, as in they didn't try. Do we have any cases where someone _did_ try and succeed in changing the world?

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

</comment><comment><USER14> Morpheus : What are you waiting for? You're faster than this. Don't think you are, know you are. Come on.

Stop trying to hit me and hit me.

</comment><comment><USER15> Jeez. I don't feel that way about anything.

<comment><USER16> Literally anything? You've never thought about an unsolved market problem and felt a rush trying to solve it in your head? Wouldn't you feel an elevated sense of purpose working for a company solving that problem, or starting a company and solving the problem yourself? You've never had fun doing something that can be commercially useful, even if you have to cross it with other domains to make money?

<comment><USER17> I genuinely can't tell if this comment is sarcasm or not.

If it's not sarcasm, fun isn't passion. Not even close.

</comment></comment></comment><comment><USER18> Everybody should read Factotum from Bukowski, it taught more about work than any other book.

</comment><comment><USER19> Sounds kind of Taoist, some parts like Catherine of Siena.

Also yoda lol

</comment><comment><USER20> link is down, anyone have an alternative link?

</comment><comment><USER21> Master Yoda put it pretty succinctly. "Do, or do not. There is no try."

<comment><USER22> But only the sith deal in absolutes.

So, work that one out.

<comment><USER23> "Only a Sith deals in absolutes."

"But wait, isn't that statement itself abs-"

" _ONLY_ a Sith, you hear me? NOBODY. ELSE."

<comment><USER24> Yoda in the prequels is a hypocrite and an old stooge who let a republic collapse.

</comment></comment></comment></comment><comment><USER25> Charles Bukowski was a man-child and a grifter.

<comment><USER26> Maybe, but he is one of the best American poets, and will remain so.

<comment><USER27> "Art is what you can get away with." - Andy Warhol</comment></comment></comment>


Facebook admits: governments exploited us to spread propaganda - <AUTHOR> https://www.theguardian.com/technology/2017/apr/27/facebook-report-government-propaganda <comment><USER3> It's easy to gather some sense of what seems like "good material" or "bad material", and easy to imagine solutions that try to block what enough people consider bad. And yet, this is not what should happen all. It is too simple, and it hides the real problem.

People need to have _critical thinking skills_ , about _everything_. "How could this be misleading?" is a valuable question to be able to ask in life, whether it is about news or the latest TV commercial or something else. It is certainly useful in capitalist systems; for instance, when being sold something and an advertisement boasts "up to 40%!", that kind of verbiage should _always_ raise questions like: "how often will this be 0% or even negative, values which are also in that range?". This kind of thing is used very frequently in advertising alone but certainly in news and even in discussions with other people. Wording is crucial, comprehension is crucial. If you ever suspect you do not really understand what you see, you need to take it as a cue to educate yourself.

Echo chambers, or silos or whatever you want to call them, should also be recognized. Skills need to be practiced, and you cannot practice critical thinking if you are surrounded by agreement all the time. This can be a hard sell because you can certainly feel a lot _happier_ when not encountering things that challenge your views but that is not how an intellectual discussion works; you need to at least accept the _possibility_ that even your long-held beliefs are not _exactly_ right.

It is dangerous for suppression tools to exist for news or anything else because, like so many things in security technology, something that's _possible_ to do can eventually be abused by _anyone_. Claims that "only the good guys will be able to use this" are not relevant to the discussion. At some point in this case, there _will_ be someone capable of masking something that he or she _personally_ does not like, and "propaganda" will have nothing to do with the mechanism by which the material is hidden.

In any scientific endeavor, you can never universally support results; you always need to know _what was considered_ to understand if the results make sense _within those parameters_. And this applies to any source of information. Even in heated political discussions, it is _way_ easier to understand why somebody may hold a view that you consider strange if you can figure out exactly what they have and haven't heard about.

<comment><USER4> Your comment me of the book Predictably Irrational. All these examples are testaments to our collective irrationality.

</comment></comment><comment><USER5> In what way?

As it stands (or once stood), Facebook more or less permits free speech on its platform, modulo pornography and gun sales. I'm against algorithmic "censorship" against their definition of "government propaganda." Let the educated reader decide that for herself (indeed, my Facebook friends -- who are also my IRL friends -- aren't agents of government propaganda by participating in our Democracy via discussing their rather-diverse political views over a public forum).

It's a little too transparent that "government propaganda" here means Donald Trump. I hope that Facebook is merely acquiescing to bad PR from the left here with a faux apology.

It's a shame that they were pressured to feel responsible when they are merely a communications medium. I don't recall telegraph operators feeling responsible for antebellum slavery or radio broadcasters feeling responsible for the rise of Adolph Hitler (of which Trump's mainstream democratic election as our President cannot even reasonably be held in comparison to either _actual_ historical atrocity).

By writing this rather dissident post here, I am not "exploiting" Hacker News.

<comment><USER6> > It's a little too transparent that "government propaganda" here means Donald > Trump.

Donald Trump wasn't a government, or in a position to direct the propaganda efforts of one, at the time of efforts to manipulate the US elections, and has never been blamed for efforts to manipulate the French elections, so, no, that's probably not what "government propaganda" means.

You may have confused Donald Trump with Vladimir Putin.

<comment><USER5> No. I try to be reasonable so I wasn't going to entertain conspiracy theories in my post (particularly when they are "convenient" scapegoats when combined with vague, evasive finger-pointing from Facebook HQ -- always be sure to ask yourself "Qui bono?" when reading these public statements). I am fully aware of FB's misguided definition of "government propaganda" and wholeheartedly feel that it is a gross misuse of the word, so yes I am aware that the ACTUAL "propaganda" here didn't come from an existing government (nor would I commit the transgression of calling the public content "propaganda").

Once there is real proof (and not the left's version of WMDs), I will happily revise my views (from the article, FB declined to provide any or even blame anybody specific).

For now, I am outraged that FB even felt compelled by certain groups to publish their own propaganda (this article).

<comment><USER7> The left's version of WMDs? It's funny that there wasn't a single propaganda campaign under Obama afaik that ever reached the depth of counterinformation as the Bush-Blair WMD campaign, yet everyone just uses the biggest lie the Bush administration ever peddled on Americans as some sort of evidence that every government does this.

No they don't. Rumsfeld had to create a special office inside the Pentagon to manufacture evidence so the WMD case could be created. They didn't use the intelligence agencies, they went around them as much as they could to create "alternate facts".

The idea that Obama has managed to do the same thing as Bush, but using 10 or so intelligence agencies to "manufacture evidence" is a lunacy. The Bush administration had to go through huge lengths to build up a false case for war. Obama just asked his intelligence agencies to give him their opinion.

You can use the crimes of the Bush Admnistration to call anything and everything that comes out of government a lie. But all that you're doing is critiquing the Bush admnistration. Not all administrations are guilty of wildly deceiving the public.

<comment><USER5> Well, I just so happen to think undermining the American democratic process by calling into question the legitimacy of the (undesired) election results is pretty serious.

This has happened time and time again anytime we somehow end up electing a Republican...

</comment></comment></comment></comment></comment><comment><USER8> Water is wet

</comment><comment><USER7> No responses yet? They are essentially admitting what we already know - <USER2> Russians brainwashed maybe a few million Americans into believing absolute bullshit, and they might've turned the election towards Trump with what we now know was a highly concise and directed effort towards the blue-collar Democrat states.

If you're going to tell me that brainwashing is not a thing, then explain how advertising exists as a billion dollar industry.

<comment><USER9> Blue collar Democrat states? Lol.

Democrats looked at the demographics and made an explicit decision to toss out blue collar (and now even white collar a la H1b) workers in favor of immigrants and corporations. The only difference between the Republicans these days is the Republicans don't hide behind their agenda by labeling those who disagree as bigots and uneducated idiots.

You can only call someone a racist, xenophobe, while they are training their own foreign replacement, for so long, before it loses effectiveness.

Do the Russians have organizations tasked with influencing foreign policy in their favor? God damned right they do, just like every major nation state on Earth. The US, btw, dwarfs the rest in this type of work.

Do these types of influence work in a vacuum? Not as well as they do when a demographic is already teetering on the edge.

<comment><USER6> > Democrats looked at the demographics and made an explicit decision to toss > out blue collar (and now even white collar a la H1b) workers in favor of > immigrants and corporations

Bill Clinton and the neoliberal DLC did, and it's been the source of a lasting divide within the Democratic Party (the party-in-government, not just the party-in-the-electorate) since; see, everything from the vote oj NAFTA through the 2016 Presidential primary and the subsequent DLC leadership campaign.

While the neoliberals are still the dominant faction within the Democratic party, they've lost ground to more strongly pro-labor progressives recently (compare 2008, when both leading primary contenders were soldily in the neoliberal faction to 2016) and there's plenty of reasons to think that will continue.</comment></comment></comment>


Microsoft experiments with DNA storage: 1Billion TB's in a gram - <AUTHOR> http://arstechnica.com/information-technology/2016/04/microsoft-experiments-with-dna-storage-1000000000-tb-in-a-gram/ <comment><USER2> > A custom DNA sequence costs about 10 cents per base, with Twist hoping to > get that cost down to 2 cents.

A quick trip to Wolfram Alpha says that this works out to about $400 million per gigabyte. Obviously it will come down, but even with exponentially decreasing cost this has a long way to go before it becomes competitive with magnetic storage. Still, it's good to see that there's more attention being paid to the need of very-long-term storage, which is woefully inadequate at the moment.</comment>


The 61 Countries a Mad Despot Could Instantly Unplug From the Internet - <AUTHOR> http://www.wired.com/wiredenterprise/2012/12/internet_plug/

<comment><USER2> Shouldn't having a "Mad Despot" also be a requirement? Both Island and Greenland are on the list, but are both democratic.

They probably have few internet providers because they are so small.

Greenland has a population of 56K. Iceland 320K and almost all live in the same city.

<comment><USER3> I don't think the map relates to the "Mad Despot", and I think it's only about risk of disconnection (including accidental disconnection). I was shocked to see Portugal there at first, but I guess they have transatlantic cables to USA or maybe to UK and not much to mainland / Spain, and that's why they are low risk.

Original's Renesys (the map creator) here: [http://www.renesys.com/blog/2012/11/could-it-happen-in- your-...](http://www.renesys.com/blog/2012/11/could-it-happen-in-your- countr.shtml) (I don't have time to parse it now, my first paragraph is just an idea)

<comment><USER4> Portuguese here.

I had a quick look at the link you provided, it has to do with the amount of national communication providers really route the traffic across borders.

Since most of the traffic goes over Portugal Telecom, switching them off, would already cut most of the traffic I imagine. Specially because they also own most of the internal cabling, even when the service is offered by other companies.

</comment></comment></comment><comment><USER5> An other interesting question is: who is at the other end of those single cables? Those parties can switch of the Internet in a neighboring country or, (worse) eavesdrop on all unencrypted traffic or (worst) silently change data (imagine modifying the contens of cnn.com or bbc.co.uk) going into and out of that country.

For example, I would hope for Cuba that their connection is to Venezuela, and not to Miami.

</comment><comment><USER6> Glad I am not living in one of those countries :))

</comment><comment><USER7> Surprising that china is low risk in their map. Their metric is clearly flawed, for china already "blocks" off the whole Internet.

<comment><USER8> I would argue the exact contrary. China tried and failed to control their internet. The famous virtual wall of china is very easily surmounted.

The metric isn't about who is more or less likely to try to isolate the country from the internet but rather how hard is it to actually accomplish such a feat?

</comment></comment><comment><USER9> what they need to be looking at are underwater cable landings [1] and not "greater than 40 ISPs".

<http://www.cablemap.info/>

</comment><comment><USER10> Do they even have the internet in N. Korea? I guess senegal in white means 'no information available' rather than 100% safe from despots

<comment><USER2> Apparently they have internet in North Korea. Even have a single Internet cafe in Pyongyang according to <http://en.wikipedia.org/wiki/Internet_in_North_Korea> .

However they could have a hundred internet providers there, but if Kim wanted to collectively log off it wouldn't help much I suppose.

It's probably not the number of service providers that matters. It's the power of the Mad Despot.

</comment></comment><comment><USER11> How are India, Estonia and Latvia on the same rung as highly suppression-ist China?

This is clearly facetious.

<comment><USER12> The same India that has been charging people with crimes for voicing criticism of politicians on the internet?

<comment><USER13> I presume you are talking about the recent "facebook related arrests". Just so you know, not every country outside the U.S., is a single monolithic block where just because some asswipe cop(s) decides to hassle kids, it means that the entire country has decided as an official policy to hassle people on that charge. Some other examples of similar specious arguments:

1\. Austria is bad because a tor exit operator got raided.

2\. The MPAA/RIAA decides to sue a bunch of kids for music torrenting. Ergo America is bad.

Also, presuming from the comment to the OP, I assume you are somehow leaping from "Charge people for criticism" to "unplug the internet": I would really love to hear your reasoning for this.

(FYI, this is not a defense of the Indian justice system or me "taking offense" or even an attempt to assert that India is not at low risk of being disconnected: I personally give 0 fucks. I just find these specious arguments silly and have no idea why intelligent people make these arguments when it comes to foreign countries. )

<comment><USER12> And you've gotten my exact point. It may also surprise you how local China's suppression is.

I'm well aware that India isn't one monolithic government (nor any other country) - I'm pointing out the exact point in OP.

For example, the many human rights abuses related to enforcing the one-child policy - forced abortions, confiscation of property, etc. If you actually look at them you will realize that the bulk of it originates in local government. Much of China's most galling, shocking abuses come from the minds of local politicians, rather than by central dictat.

The rampant nepotism and corruption in the Chinese government is largely an expression of just how little control its central authorities have over their localized branches.

Moral comparisons between countries is usually ill-advised for this exact reason. This sort of baseless moral superiority bugs me - India is not nearly as far from China as OP seems to think it is, at least when it comes to online freedoms.

<comment><USER13> > Moral comparisons between countries is usually ill-advised for this exact > reason. This sort of baseless moral superiority bugs me - India is not > nearly as far from China as OP seems to think it is, at least when it comes > to online freedoms.

Completely agreed on making moral comparisons. I have noticed this in a few threads involving developing countries where people emerge out of the woodwork to rant about either A) How everyone is victimizing aforesaid developing country and they should just stop. or B) Make a completely irrelevant argument about how the developing country in question making progress in X is irrelevant because of abuses or oppressions or whatever. Both of these are from opposing camps but are founded on bad logic.</comment></comment></comment></comment></comment>


Art of Computer Programming, Volumes 1-4A Boxed Set - <AUTHOR> http://www.amazon.com/Computer-Programming-Volumes-1-4A-Boxed/dp/0321751043/ <comment><USER2> Can somebody elaborate on the use cases of such a set? Are these volumes more theoretical and academic or practical? Is ownership more of a symbol or are they genuinely interesting to read, given a cramped startup lifestyle? What level of formal comp sci education does the author assume?

Not skepticism, just genuine curiosity and intrigue. I don't have a formal CS background, so forgive me for the naiveté if this is obvious stuff.

<comment><USER3> This will likely not help you build your startup unless you need a really strong understanding of Programming concepts. In the words of the wise Wikipedia:

"The famous offer of a reward check worth "one hexadecimal dollar" (100HEX base 16 cents, in decimal, is $2.56) for any errors found, and the correction of these errors in subsequent printings, has contributed to the highly polished and still-authoritative nature of the work, long after its first publication. Another characteristic of the volumes is the variation in the difficulty of the exercises. The level of difficulty ranges from "warm-up" exercises to unsolved research problems, providing a challenge for any reader."

For some people, it will be a status symbol. But honestly, you shouldn't be buying these books unless you actually want to learn something. Just saying you have the books will do you no good and is just a waste of paper.

<comment><USER4> I cashed one of those checks once, after photo-copying it first of course. Seems like I paid a lot less for the boxed set of 3 volumes about 13 years ago. I would like to pre-order the hardbound vol 4a.

</comment></comment></comment><comment><USER5> BTW, I have an extra set of volumes 1-3 that I got by mistake, if someone's around Paris, mail me to get them. A poor student would be best :)

</comment><comment><USER6> These books are more than a status symbols for aggressive learners. I've poured through many chapters in these books and it really challenged me and continues to solidify a lot of concepts about computer programming.

I particularly remember enjoying being enlightened on where Big-O came from and what is really means in the mathematical world. Really helps me derive Big-O notations from my programs.

</comment><comment><USER7> Probably more of a status symbol for most people.

How many of you actually read these books carefully?

<comment><USER8> I've read parts of vol. 2, especially about random number generation. I found it in a library book sale for a quarter. THAT made my day. :)

I've found a suspiciously high percentage of the people who have totally! read the Art of Computer Programming are unable to answer even basic questions about MIX, by the way.

<comment><USER9> That's because there is a big difference between reading and understanding.

Reading can just mean reading word by word, symbol by symbol then putting the book on the shelf. That ends up happening a lot with material that has a lot of formulas and theorems. It could take days for some to understand just a couple of pages.

So basically I not surprised at all that you've met so many people who've read the volumes, but didn't all the subtleties.

I think reading the volumes is the next step in status show-off step after buying and putting them on the shelf.

Also, as many have pointed that MIX is just too obscure. Not knowing much about doesn't really indicate a lack of theoretical knowledge. I would personally skipped over those chapters.

<comment><USER8> I was more thinking along the lines of, "Oh yeah, I've read them all. Wait, MIX? What's that?"

I've seen several equally dense, informative CS books (such as Dick Grune's _Parsing Techniques: A Practical Guide_), but Knuth has a specific sort of cachet among xkcd-quoting geek hipsters, so people namedropping him, make a pretense of having read them all the way through, etc.

</comment></comment></comment></comment><comment><USER10> _clicks on "Tell the Publisher! I'd like to read this book on Kindle"_

<comment><USER11> So would I - but only if it looks as beautiful as the real thing.

Anyway, don't most people buy those as shelf decorations?

<comment><USER12> Hardback edition $200

Kindle edition $100

Empty slipcase with fake spines to impress your friends $50

<comment><USER13> Buy one real, so you can take it out.

</comment></comment></comment></comment><comment><USER14> These seem to be a perfect graduation gift.

</comment><comment><USER15> Seriously, a list price of $249? Hardcover books are so damn expensive...

<comment><USER12> Sure and what do you get for the price of an iPod?

The life's work of the greatest genius in CS and a set of knowledge that will last you more than your lifetime.

<comment><USER15> Hey, I am not disputing that the content isn't worth while. I just would rather have it in paperback (which is already out, I believe) so it's cheaper and easier to flip through. But I guess that is just my personal preference.

<comment><USER12> I have a paperback edition printed on almost tissue paper I bought in India 10 years ago for about $5

</comment></comment></comment></comment><comment><USER16> Does anyone if you can buy a cardboard mockup of the boxed set that would look like the real thing when placed on your bookshelf next to "Teach Yourself Ruby in 21 Days"? I'm thinking $5.

</comment><comment><USER17> I have a hard bound set (without the case) that someone can have if they are around the San Jose area. Vols 1 - 3. Maybe a trade or something?

</comment><comment><USER18> So is this just the beginning of part 4?

<comment><USER12> Yes - but the whole of volume 4 is almost a lifeswork! see <http://www-cs- faculty.stanford.edu/~uno/taocp.html>

</comment></comment><comment><USER19> Anyone know if these are all updated to the RISC system, or is that still in progress?

<comment><USER20> That's still in progress (and, given that Knuth is more than seventy years old and still has at least 3 books to go before he will begin to revise them, odds are such a revised set will never be released).

<comment><USER19> That's kinda what I was anticipating. But a guy can hope, right?

<comment><AUTHOR> Knuth still seems hopeful, so we might as well join him.

</comment></comment></comment></comment><comment><USER21> oh hell NO!</comment>


Hydrides come within a whisker of room temperature superconductivity - lachlan-sneff https://www.chemistryworld.com/news/hydrides-come-within-a-whisker-of-room-temperature-superconductivity/3010030.article <comment><AUTHOR> Is there a measurement for how much power a superconductor of a given diameter can actually conduct? Of course we're all familiar with the "resistance = 0" concept but I don't think that means you could pump ten billion amps through a superconductor the diameter of a hair, or does it? What other forces limit high-density current flow besides simple resistance?

<comment><USER2> What limits it is that superconductors can only handle a certain density of magnetic flux; more than that will make it stop superconducting. (This property was used in the "cryotron", an electrical switch used in some early computers before transistors became common for the same function.) Any current-carrying wire produces a magnetic field; so, with a strong enough current, the magnetic flux will cause the superconductor to switch itself off. This can be limited by using a larger superconductor, so the flux density is lower.

<comment><USER3> What happens if a conductor (regular wire, not a superconductor), is wrapped in a magnet that "matches" the magnetic field produced by the wire?

<comment><USER4> You can do this to enhance or change the magnetic field of the magnet. Core rope memory and such use this principle to read, write and refresh the contents of the cores. They send a pulse down one of the lines, read line sends one voltage, write line sends a higher one designed to flip the polarity if necessary, and then sense the reflected pulse on the third wire, called the sense wire.

<comment><USER3> Thank you for the explanation. I'm still confused. So if a wire is wrapped in a specially crafted magnet, then when sending an electric pulse through it the pulse will "bounce back"?

</comment></comment></comment></comment></comment><comment><USER5> This article is from January but things do seem to be suddenly getting exciting around room temperature superconductors again. The preprint mentioned in the paper became an article in Nature in May. Moreover, the fact that there now seem to be way to design superconductive materials rather just stumble into them could be a game changer.

<comment> lachlan-sneff A few months back, a team reported that they'd found room-temperature superconduction in gold/silver nanoparticles. Unfortunately, there has been no more news about it since.

</comment></comment><comment> lachlan-sneff I wonder if the path to room-temperature superconductors involves finding ways of containing hydrides at very high pressures, rather than finding materials that superconduct and ambiant temperatures and pressures.

<comment><USER6> I have the feeling it will be more economical to just use a low-temperature superconductor and cool it down with a closed-cycle cryocooler, rather than try to get a large enough pressure vessel that can maintain such high pressures.

<comment><USER7> A few years ago, that was the thinking when a 'high temperature' (much colder than room temperature) superconducting cable was trialed in Germany [1].

[1]: [https://www.tdworld.com/overhead-distribution/ampacity- proje...](https://www.tdworld.com/overhead-distribution/ampacity-project)

[2 with follow-up presentation]: [https://snf.ieeecsc.org/abstracts/stp475-ampacity- project-%E...](https://snf.ieeecsc.org/abstracts/stp475-ampacity- project-%E2%80%93-update-world%E2%80%99s-first-superconducting-cable-and- fault-current)

</comment></comment></comment><comment> d--b > Attaining superconductivity requires the diamond anvil cell to exerts > pressures of up to 200GPa, two million times that of the Earth's atmosphere.

<comment><USER8> _At high pressure_ might be to superconductivity research what _in mice_ is to medical research.

That doesn't mean that it is not useful to conduct these experiments. They could give further insights into how superconductivity comes to be - or maybe discover a superconducting material that requires high (but not too high * ) pressures to form but remains stable when they are lowered back to normal pressure similar to how diamonds are stable at normal pressures but are require high pressure to be formed.

* Pressures only reachable by using diamond anvils would be highly impractical to produce any useful amount of material ;)

<comment><USER9> I think he must meant that the headline is misleading. The holy gain is room temperature superconductivity _at room pressure_.

<comment><USER10> Depending on the application, mechanically useful pressures and higher temperatures might be good enough.

<comment><USER11> "Room temperature" already makes this concession as it means above 0C. In the context of superconductivity I would assume "room pressure" to fairly encompass pressures higher than 1 atm, though I don't know if there's a practical cut-off as there is for temperature.

</comment></comment></comment></comment></comment><comment><USER12> I would love a CPU that ran at room temperature.

OK, it's a cart and horse affair as it is the resistance that causes the heat, but I'm mindful how lab work pans out into real-work. But even reducing resisting a bit in a practical, consumer useful way has massive benefits.

<comment><USER13> Technically, yes, "resistance causes the heat" \- but why? Well - because in a CPU, voltages are being manipulated.

Those voltages represent binary values. Usually a positive voltage is designated as a binary "1" and a zero voltage as a binary "0". Putting a "1" into a register (or whatever) is easy - just add the appropriate voltage. But how do you change that "1" into a "0"?

You do so by "grounding" the circuit - that is, a circuit is made where the voltage level representing the "1" is connected to the reference voltage level that represents "0". Since that voltage level is "0 volts" (usually - but not always - but it is usually lower than the voltage level representing "1"); that change in voltage happens to occur across a conductor, and that conductor has some resistance, and that ultimately is what generates the heat.

ASIDE: It is possible to reverse all of this - that is, use a negative or zero voltage to represent a "1" and a positive voltage to represent a "0", and so on - I'm not sure, though, that this is done in common practice, but I am certain it has been done somewhere at least once.

So - what does that mean? Well - it means that in a CPU, just by the fact that it is manipulating voltages that represent the binary symbols "1" and "0" \- it is going to end up generating some amount of heat. The fasting these changes occur, the more heat that is output. The larger the voltages involved, the more heat is output (note how this explains why, as CPUs have gotten faster, their operating voltages have become lower).

How do you combat this? Well - it ain't easy - but what if you could, instead of grounding a voltage representing a "1" to make it a "0" \- you instead used it elsewhere (in some manner) to generate a "1". That is, instead of wasting that voltage and energy as heat due to resistance, you used it instead to perform the opposite function elsewhere in the CPU?

Well - you can - though it ain't easy from what I understand. It's called:

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

<comment><USER14> To vastly simplify: Since one signal is zero resistance (zero loss) and one signal is infinite resistance (zero loss), switching between the two requires a finite time spent at a resistance between the two (nonzero loss). Every change requires a change in entropy to represent it. This is also known as Landauer's principle: [https://en.wikipedia.org/wiki/Landauer%27s_principle](https://en.wikipedia.org/wiki/Landauer%27s_principle)

> How do you combat this? Well - it ain't easy - but what if you could, > instead of grounding a voltage representing a "1" to make it a "0" \- you > instead used it elsewhere (in some manner) to generate a "1". That is, > instead of wasting that voltage and energy as heat due to resistance, you > used it instead to perform the opposite function elsewhere in the CPU?

That's different and wouldn't really apply to a concept like resistance. It also doesn't need to be the opposite function, just... something.

<comment><USER15> >>but what if you could, instead of grounding a voltage representing a "1" to make it a "0" \- you instead used it elsewhere (in some manner) to generate a "1"

that leans towards reversible computation, which would need a reversible computer (getting close to unitary transformations in QM)

</comment></comment></comment></comment><comment><USER16> Is it correct to think that because of entropy of heat, it is harder to make atomic structures stable enough to form a perfect path for electrons to run without loss at higher temps?

<comment><USER17> I hope this is the right description because it would make such intuitive sense.

But superconductivity is also a quantum phenomenon so it probably defies intuition.

</comment></comment><comment><USER18> I ponder if the sun is a really large super conductor? Since the sun has really high pressure like in the article and it has largely a lot of hydrogen like in the article. [https://en.wikipedia.org/wiki/Sun](https://en.wikipedia.org/wiki/Sun)

<comment><USER19> I don't know if it is superconductor, but plasma is somewhat conductive because it is consists of charged particles.</comment></comment>


Nathan Myhrvold's Patent Extortion Fund Is Reaping Hundreds Of Millions of Dollars - <AUTHOR> http://www.techcrunch.com/2008/09/17/nathan-myhrvolds-patent-extortion-fund-is-reaping-hundreds-of-millions-of-dollars/ <comment><USER2> Perfect. The system won't get fixed until someone uses it to the full extent.

Lets remember that it is big corporations that lobby for the kind of patent and IP law that makes this possible.

On top of that, you have the over loaded patent office assuming bad patents will get sorted out in court. While at the same time judges assume that if a patent was granted it was legit.

To fix the system, you have to break it first.

Perfect.

<comment><USER3> I hope your logic does not also apply to representative government :-/

<comment><USER2> Sadly it kind of does. It's surprising just how many governments have followed the same pattern.

First they grow and grow and grow. Reform is occasional and minor (at best), eventually they get so big and bad that a crisis forces real change.

The state is then transformed into a lean mean productive machine. Which starts to grow slowly and the process repeats.

Of the top of my head I can think of Sweden, where a crisis forced massive reform and now it's almost ready for a crisis again.

And Great Britain in the 1970, crisis -> Thatcher -> prosperity -> growing government -> less prosperity -> coming crisis.

Guess where the US is in that cycle.

<comment><USER4> Interesting to see how that follows the cost of a barrel of crude oil.. roughly

</comment></comment></comment></comment><comment><USER5> I met Nathan Myhrvold while giving his son a tour of my school. He struck me as a much nicer guy than what all of these articles play him up as. Extortion is almost certainly too bold of a term for what his company does.

The patent system was set up to be taken advantage of in this exact way. If someone comes up with/legally documents an idea before you do, you have to get them to let you use it (via licensing fees). I don't see how that's tantamount to protection money. If you're one of the companies involved, there's pretty clear net gain for you since you're essentially outsourcing R&D to some smart people and virtually extending your patent portfolio at the same time, which is an asset on its own.

<comment><USER6> >> The patent system was set up to be taken advantage of in this exact way

Pheraps, but the question is should it be set up this way? Two justifications of the patent system are

\- inventors have more incentives, hence new ideas will emerge faster

\- when these new ideas/inventions emerge, the patent ensures that it is openly documented and hence, can be used by everyone after the patent expires.

And the price that one pays for this is that noone can use the idea without a deal with the patent owner. Is the price worth the benefit? This depends on things like a) how easy it is to discover the idea

Two extreme cases would be say , a cure for AIDS vs. one-click patent

b) the existence and the power of non-patent incentives for the discovery of the idea

Would the idea be discovered without patents? Ideas/inventions are discovered all the time simply because one is working on some problem and one needs new tools to solve it. The university system is also a strong alternative system of incentives. But, there will be holes in what these systems incentivize.

c) how many things depend on the thing being patented?

This is a kind of an amplifying factor. Say, there a huge number of systems which depend on an idea. If the idea could be discovered without the patent system, the economy loses a lot of value and on the other side if patents were what made the discovery possible, then the patent system has caused great gain. Software, where ideas are built upon each other at great speed is full of these amplifying factors. A patent on say, garbage collection or oop, if granted, would affect a huge number of systems.(though, probably this would have expired before the 90's, but consider more recent ideas like say, stm.) the the rapid growth of the computer industry in the current phase increases this amplifying factor.

d) The negative effect of patents on the culture of open sharing of ideas. Precisely, because people are doing this without making money, there is little scope for licensing from the patent holder. And this culture has a lot of value, intrinsic, educational and economic.

Abolishing patents would probably be bad,(unless we can make alternative systems of incentives work. prizes?) But the important point here, is that there are a lot of free parameters - the length of patent, limitations on licensing fees, the nature of things which could be patented(i have used ideas/inventions interchangeably, but this is a controversial issue)

Deciding optimal values for these parameters is a complex task and it isn't clear how one should be doing this. For instance, the length of the patent, if decided in a market would probably vary with the field in which the idea applies. For some fields, the optimal parameter might well be 0.

<comment><USER7> Well thought-out. I agree almost entirely.

Our current patent system clearly needs much improvement, but almost certainly encourages progress far beyond none at all.

I don't see prizes as being too effective. The nice thing about the market is it decides what problems are worth solving. Prizes put that decision in the hands of whoever organizes them.

There would clearly be prizes for fighting cancer, aids, lack of potable water, etc. I'm not sure there ever would have been a prize for a pot with a tight fitting lid and holes in it, but the Pasta Pot, simple as it is, is a miracle. Same with wheels on luggage, the SpinBrush, etc.

But our current patent system has a solid prize that encourages innovation from products as small as those all the way up to nanotech.

</comment></comment></comment><comment><USER8> It's surprising how many people (in the comments) are outraged over what is basically a way for someone who is not a big company to outsource the inevitable legal wrangling of commercializing their invention.

What _is_ broken is that the patent office and courts have completely ignored that whole "obvious to a practitioner of the art" thing. Patents are supposed to protect novel inventions. Instead people get patents for deciding to enter a market first.

Invalidating Amazon's "1-click shopping" patent shouldn't require prior art, but just a simple poll of the tech community saying "duh, that's what cookies were designed for".

<comment><USER9> _It's surprising how many people (in the comments) are outraged over what is basically a way for someone who is not a big company to outsource the inevitable legal wrangling of commercializing their invention._

What most people miss about rackets like this is that even after you pay off vultures like these they almost never offer you _indemnity_. That means some one else can sue you for _exactly the same technology_ with a similar vague patent claim. In fact, they probably will, since you seem willing to pay.

<comment><USER8> Their (new) client's implementation could very well independently violate another patent or an unknown extension of the licensed patent. What would they gain from taking on this risk?

The broken patent system has bumbled along precisely because large companies generally have cross licensing deals with each other, leaving only the little guy subject to vague infringement claims. Now that there's a well-funded company which doesn't require 'incoming' licenses (by not making anything), there's real money involved for the big guys.

On another day I might be arguing for abolishing patents, but I just don't see how this is an abuse of the current system.

</comment></comment></comment><comment><USER10> I have to give him credit for being clever. Broken system? yes. Clever? yes.

It seems as if these big companies simply invest in his fund as a hedge to the licensing fees they are going to have to pay.

</comment><comment><USER11> I love how the spirit of MS lives on strong in their alumni...

<comment><USER12> You mean, "If you don't feel like providing value, then find a work-around."

<comment><USER13> That would be a "feature."

</comment></comment></comment><comment><USER14> It's broken in the same sense that the domain name registration system is broken. Spend a little money and you can roadblock a lot of ideas.

<comment><USER15> Very few good ideas are dependent on getting a certain domain name.

<comment><USER16> But you can roadblock a lot of good domain names with a little money.

</comment></comment></comment><comment><USER17> Have any small or medium-sized businesses stood up to this bullshit in court? I would like to imagine that if I were in the situation of being sued by one of these patent-wielding cowards I would say no to licensing and the inevitable attempt at settlement.

</comment><comment><USER18> ...and he hasn't even had to sue anybody yet.

With Danny Hillis, Neal Stephenson, and Sanjay Prasad (former chief patent attorney at Oracle, and an ouspoken proponent of patent reform) on board, I doubt that it's your garden-variety patent troll.

</comment><comment><USER19> if person.has_idea? && person.can_afford?(patent_attorney) { business.start! }

makes an entrepreneur hope that his idea stays under the radar.

</comment><comment><USER20> How can we stop it?</comment>


RevMobile and Apple's new iPhone SDK Agreement - <AUTHOR> http://www.runrev.com/company/runrev-blog/revmobile-and-apples-iphone-sdk-agreement/

<comment><USER2> would love a little more details on this crucial line: "Steve Jobs has now rejected our proposal and made it clear that he has no interest in having revMobile available on the iPhone or iPad in any form."

<comment><USER3> Sure, but how is this line crucial? Do you disagree with the analysis that 3.3.1 clearly bans his company's application?

<comment><USER4> Well, I think there has been a kind of "wait and see" attitude to see if 3.3.1 is really about the language it was written in or if it is just a means to ban flash.

We know PhoneGap is in which is designed for cross-platform, but only uses Javascript in Webviews. What about Titanium which creates an xcode project?

I for one am really curious for any official information on the application of 3.3.1 and that line seems to imply official information.

<comment><USER5> PhoneGap is explicitly OK according to the requirements, Titanium isn't.

There's no wait and see, it's "build and pray".

</comment></comment></comment></comment><comment><USER6> revMo was the wrong product anyway; what's needed is a HyperCard-like dev environment _that runs on the iPad_ and can open stacks-or-whatever from other users. I hope they get to work on that.

<comment><USER7> Anything like that has always been prohibited by Apple's license.</comment></comment>


Ask HN: How would you approach horizontal scaling of your software? - <AUTHOR> Hi,
I'm currently thinking about how to best implement partitioning/replication of my Open Source storage system written in Java. I've read "Designing Data-Intensive Applications: The Big Ideas Behind Reliable, Scalable, and Maintainable Systems" which is a great book, but I'd love more resources. At work we basically used Ignite for our application and horizontal scaling in the Cloud with a distributed file system, but the latter is something I clearly want to avoid.
So, do you have some resources/tips? I clearly want to have transactions based on some consensus algorithm and a single leader, which accepts writes. But basically I want to read more about the whole topic before moving forward and develop epics/tasks.
Do you have any resources / best practices? Nowadays it seems that almost everyone puts his software into the cloud via Docker/Kubernetes and some data grid, but I guess it's still complicated to do it right :-)
Kind regards and happy easter Johannes <comment><USER2> [https://en.wikipedia.org/wiki/Apache_ZooKeeper](https://en.wikipedia.org/wiki/Apache_ZooKeeper) was created to help other systems scale horizontally, e.g. it takes care of [https://en.wikipedia.org/wiki/Leader_election](https://en.wikipedia.org/wiki/Leader_election) and all the edge cases one would want to "outsource".

<comment><AUTHOR> Hey, thanks :-) it could also be done via Apache Ignite, I think... but Zookeeper might be much more advanced in this regard. Thank you :-)</comment></comment>