Arrow of time and its reversal on IBM quantum computer (2018) - <AUTHOR> https://arxiv.org/abs/1712.10057 <comment><USER3> I don't know enough quantum physics. Is this a qubit equivalent of reversing the mixture of dyes in viscous liquids?

[https://sciencedemonstrations.fas.harvard.edu/presentations/...](https://sciencedemonstrations.fas.harvard.edu/presentations/reversible- fluid-mixing)

<comment><USER4> Close enough for a popsci article!

<comment><USER5> I agree. There are a million of differences, but the main idea is the same. You go from an very ordered state to an state that looks unordered, but it's actually very specific state (with a weird order that is not evident).

Then in one case you reverse the mechanical part and the fluid movement is reversed and you get back to the initial state. (Well, almost the initial state because there is some diffusion and other non reversible effects.)

In the other case, you apply a transformation that reverse the "speed" of the particles (even if they are entangled, without destroying the entanglement, here a few technical details that is better to avoid), and you get back to the initial state. (Well, almost because if you are unlucky soothing can affect unexpectedly the system and you loose the control and you don't return to the initial state. Errors like this are more probable when you use more qbits.)

</comment></comment></comment><comment><USER6> I'm not a physicist, but isn't this kind of like building a fridge and saying it's reversing time because it makes it look like the usual process of heat dissipation is running in reverse? Or is there something more fundamental going on here?

<comment><USER7> That's not a bad analogy. The difference is that the fridge requires energy input, while quantum "time reversal" does not. I'm putting "time reversal" in scare quotes because it's not really reversing time, it's "simply" (again in scare quotes because actually doing it is not so simple) reversing the normal direction of the evolution of a quantum process.

<comment><USER8> How do we know that there are no work done by the computer on the states?

They didn't test for eg. 010 back and forth. There might be a 000 bias, etc.

<comment><USER7> I don't know what you mean by "010 back and forth" or "000 bias", but I'm talking about theory, not practice. Even under ideal conditions a refrigerator requires energy input in order to work. A quantum computer does not. I have no idea whether this particular implementation was dissipative or not.

<comment><USER8> The autors write that the registers went from 000 to something and back approx. 50% of the time when the random chance of it was really small.

An ideal 386 computer could be thought off as not requiring energy too, right? A looping pseudo random number generator would then be time reversal. It's not saying anything really.

</comment></comment></comment></comment></comment><comment><USER9> It's like saying picking up a ball from point A and putting in point B, then taking it from point B and putting back in point A is "reversing time".

<comment><USER10> Yeah, this is a poor use of words. I was actually hoping they had read some quantum information "from the future" but in a way that precludes transmitting useful information to the past - similar to how entangled pairs seem to transmit information faster than light, but in a way that doesn't enable FLT communication. But no, nothing about this suggests anything to me about reversing time. Reversing decoherence (if that's a better description) is nice but it's not about time reversal.

<comment><USER11> > similar to how entangled pairs seem to transmit information faster than > light

If your lover sends you a left-half heart locket through the postal service, when you get it you can assume he has the right-half of the locket "faster than the speed of light". However this is cheating because to know that he has the other half requires prior knowledge of the exchange--either he sent a previous letter where he stated his intent, or you just made an assumption about the state of the environment (namely, that your partner is the only one who would send you presents in the mail). In either case, no laws of physics need be broken.

<comment><USER12> This is absolutely not how entanglement works. This analogy requires the locket half you receive to be defined at time of "entanglement" (when the locket halves are separated & sent). Half a century of Bell experiments have told us that the result of measuring an entangled system is defined at time of measurement, not at time of entanglement. If it were defined at time of entanglement, the particles would have to carry information with them to "remember" how they decided to collapse (a local hidden variable). Bell experiments disprove the existence of local hidden variables as a means to explain entanglement.

I wish people would stop posting these third-hand metaphors about quantum entanglement being like finding a single right-handed glove in your pocket or whatever. They are irredeemably flawed and completely misrepresent how entanglement works.

<comment><USER11> Yes my analogy had a hidden variable, but it is "less wrong" than saying that entanglement allows FTL communication, for reasons analogous to those that I provided at the end; entanglement can only convey _information_ as fast as light because the two parties detecting the entangled particles aren't communicating they are just on the receiving end of a shared experience. I don't think I can explain entanglement to a lay person more succinctly than the locket/glove analogy, even though it does hand wave the most quantum-ey part of the experiment.

<comment><USER12> But I feel this harms more than it helps, like saying "quantum computers compute with every possible value simultaneously in superposition" which gives the audience a very flawed understanding of how QCs work (that they'll be able to solve NP-complete problems in polynomial time for example). By phrasing quantum phenomena in terms familiar to the classical audience, we do them a disservice; we are lying to them.

In this case, the question "why doesn't quantum entanglement enable FTL communication?" is properly that the reduced density operator of an EPR half is the maximally mixed state. All we can do to simplify that is to tell them that quantum concepts exist outside of classical language, and in order to understand them they'll have to learn a new language - mathematics. The most you can say is quantum entanglement enables FTL "correlations" which are stronger than classical correlations but not strong enough to enable information transfer.

<comment><USER13> Not encountering this for the first time, I've given much thought to your position over the years. But according to many mathematicians, mathematics is within the purview of natural language[1][2]. And wasn't it Feynman himself alleged to have said if we can't explain something in a lecture intended for undergraduate freshmen, we don't really understand it? [3, p19].

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

[2] [http://www.cut-the- knot.org/language/MathIsLanguage.shtml](http://www.cut-the- knot.org/language/MathIsLanguage.shtml)

[3] [http://calteches.library.caltech.edu/563/2/Goodstein.pdf](http://calteches.library.caltech.edu/563/2/Goodstein.pdf)

EDIT: This is not to challenge your specific assertions on this topic - <USER2> which I cannot speak with any particular authority.

<comment><USER12> Undergraduate freshmen are perfectly capable of understanding basic linear algebra, and thus quantum entanglement.

Regarding the nature of language and how it relates to mathematics, I don't think it's correct to say math is a "subset" of language; there is no satisfactory definition of language that encompasses all the way humans communicate with one another, and it makes more sense to restrict the definition of language to its use in specific interactions (the language of interacting with a cashier to buy an item from a store, and the different language of telling your team what you worked on during standup, for example). In this sense the use of mathematics to describe quantum mechanics is a language in itself.

<comment><USER13> Sorry, my earlier use of the word subset was a mistake and I have edited the sentence in question to say "within the purview" which is more what I had in mind. I appreciate your reply and do agree with your final statement, though I'm not really sure on the idea of restricting the definition of language as you've described and personally have trouble finding such delineations.

<comment><USER12> You can read more on Wittgenstein's idea of "language games" here: [https://plato.stanford.edu/entries/wittgenstein/#LangGameFam...](https://plato.stanford.edu/entries/wittgenstein/#LangGameFamiRese)

</comment></comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER14> I suppose this is interesting because unlike cleaning up one's room, (an example of equivalent "time reversal" given by an obnoxious commenter on the article site), this appears to be total time reversal. All properties of the system are set in reverse (where the system obviously does not include the outside world and apparatus which has been contrived to reverse the qubits). Whether this has any real value seems debatable, but it's pretty neat to know that we're even capable of such precise reversal of a basic quantum system.

<comment><USER15> No, it's actually just like cleaning your room.

Imagine your room (system) has three objects (quantum state) whose respective positions are (a, b), (x, y) and (p, q). You move the objects in your room to positions (a + k_{1}, b + k_{2}), (x + j_{1}, y + j_{2}) and (p + m_{1}, q + m_{2}), respectively. You know where the objects were before and you move them by adding or scaling their coordinates within the room. Thus you know how to move them back to precisely where they were before.

Likewise, this process is linear and preserves all information inherent to the system. Therefore it's precisely invertible, and voila.

It probably has some kind of value and it's a neat result, but this doesn't constitute time travel (in any meaningful sense) in the nonlinear world we reside in.

EDIT: Come to think of it, this probably has value for debugging and auditing the states, as a perfect rewind stepping function.

<comment><USER14> It's only roughly equivalent to cleaning your room, in a hand-wavey way. Is your cleaned room in an identical quantum state as it was a week ago? No? Well, then the situations aren't the same.

<comment><USER15> Yes of course it's hand wavey, all analogies are hand wavey. That's why they're called analogies and not lectures. You don't devise an analogy to deliver all the academic rigor of a topic, you devise it to ground something back into the realm of the intuitive and familiar.

Not all analogies are useful, but the reason _this_ one is useful is because it captures the heart of why this isn't meaningfully "time reversal." If you have all information about a linear system, yes you can transform it back into its previous state. That's not at all mysterious or unintuitive even if it's a technical achievement.

Obviously reality is nonlinear, which is precisely the point the analogy is trying to capture. We're not trying to teach quantum mechanics here, we're trying to make sure people don't come away from the article thinking the second law of thermodynamics is (non-locally) violated or that time travel at the macro level is plausible.

The basic idea is that you did a reversible thing, then reversed it.

</comment></comment></comment></comment><comment><USER16> I don't think this breaks the second law, it sounds like they put some energy into the system to reverse the process

<comment><USER5> This experiment doesn't break the second law, because they have perfect knowledge of the intermediate states, so they can apply a transformation to invert the evolution.

In a big macroscopic system this is imposible in practice, because you only get a parcial knowledge of a few important properties, not of every detail.

Moreover, in most systems it is imposible to know everything about the system, but in some specially build systems like a quantum computer you can know the state of all the qbits.

<comment><USER16> The reason I made the statement was because the article said

'"This is one in a series of papers on the possibility of violating the second law of thermodynamics. That law is closely related to the notion of the arrow of time that posits the one-way direction of time from the past to the future," said the study's lead author Gordey Lesovik, who heads the Laboratory of the Physics of Quantum Information Technology at MIPT.'

When I don't see how violating the second law could even be a possibility.

<comment><USER5> I think we both agree that this is not violating the second law of thermodynamics.

We disagree in that this time reversal operation need energy. It's possible to do this experiment with a frequency doubler [1] crystal in reverse to split a photon in two photons with less energy, then use mirrors to reverse the photons, and then you will be able to "see" that the photons return to the crystal and produce the original photon. [Good luck aligning all the optical equipment perfectly. This is theoretically possible, but it would be very difficult to make the experiment. Perhaps it's easier with other particles.] Anyway, the time reversal operation in this experiment only use a few perfectly aligned mirrors, so it doesn't need additional energy.

In the experiment in the article, they use a setup that is like a quantum computer. It use energy to keep everything working, but the additional energy is not necessary for the main part of the experiment. (The energy is important to make the experiment possible, i.e. transform "perfect alignment" into "we can build this".)

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

</comment></comment></comment></comment><comment><USER17> Sounds like they implemented a theoretical architecture called uncomputing. Apparently useful for all sorts of theorized quantum algorithms.

[https://www.scottaaronson.com/democritus/lec10.html](https://www.scottaaronson.com/democritus/lec10.html)

</comment><comment><USER18> Is this the same quantum computer that had the weird promo video where they talked at length about assembling it in Italy out of aircraft-grade aluminum and didn't mention benchmarks/capabilities?

</comment><comment><USER17> Sounds like they implemented a theoretical architecture called uncomputing. Apparently useful for all sorts of theorized quantum algorithms. [https://www.scottaaronson.com/democritus/lec10.html](https://www.scottaaronson.com/democritus/lec10.html)

<comment><USER19> Uncomputation is a fundamental concept of quantum computing. You cannot isolate a meaningful result without it.

<comment><USER17> So did I get it right... Is that what they are talking about as time travel? It sounds a lot like it to me

</comment></comment></comment><comment><USER20> Alternative theory: they reversed a quantum state while moving forward in time. The researchers, the computer, etc.

<comment><USER21> Time-travel as popularity conceived is the same: reverse the state of everything outside the time-machine while everything inside progresses as usual.

</comment></comment><comment><USER22> Interesting that many of the comments here attempt to label this as false research simply because it's taking one state and changing it to another.

Absent from the conversation seems to be agreement on what exactly "time" is.

Much has been studied and said about time, but if we think of time as being something other than an observable change—or that of a recognizable, unified state to one of chaos, aka entropy—what is it?

<comment><USER22> I'd add here that the observations of this research aren't that striking. We've known for some time that time may not be a single direction arrow but rather one pointing both ways, dependent on what we're observing and our classification of what's possible.

In his book Your Brain is a Time Machine, Dean Buonomano gives an excellent and well-written example of how studies like the one reported here actually work. A favorite quote of mine from that section sums the point as so:

"Decreases in entropy are improbable, not impossible, and given enough time the improbable becomes probable."

<comment><USER22> These were dumb comments for me to make, I wish HN supported deletion at times like these. Oh well.

</comment></comment></comment><comment><USER23> Does anyone know if this has any implications for reversible computing? I haven't the expertise to draw links between the two topics.

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

</comment><comment><USER24> Aside from the clickbait title, can anyone please ELI5, TL;DR this paper?

From abstract: Here we show that, while in nature the complex conjugation needed for time reversal is exponentially improbable, one can design a quantum algorithm that includes complex conjugation and thus reverses a given quantum state.

<comment><USER25> A physics simulation usually simulates the future, but there is nothing stopping you from running the code "backwards" in order to study the past state of the system. If we want to sound fancy we call this "reversing time".

In the case of a quantum computer simulating something (we can not really do this yet, but we are hard at work building the hardware) that type of reversal might require us to calculate complex conjugates of quantum states. For various reasons this is nontrivial and this paper describes ways to do that.

<comment><USER26> Another physics layperson question here: Can this technique of studying a past state reversal apply to compromising one-way hash functions in some manner?

<comment><USER25> No! Contrary to what the sibling comment says, there are plenty of one-way hash functions that are resistant to quantum computers. Two comments though:

1\. This particular work is explicitly relying on the fact that many quantum operations (including the type of time evolution they are considering) are a one-to-one map (not the one-to-many "irreversible" hash functions). Hence this work is explicitly not applicable.

2\. Quantum computers do break some form of public key encryption, but this is a solved problem, as there are many other public key encryption protocols that are can not be broken by a quantum computer. Quantum computers do provide modest speedup in all types of brute force searches, like breaking symmetric encryption, but this is trivial to defend against by using a slightly bigger encryption key.

</comment></comment></comment></comment><comment><USER27> Quantum computing is reversible right?

Can anyone who knows this field describe what they did? I assume it's more exciting than applying a gate followed by its inverse.

<comment><USER12> It is not in fact more exciting than that.

</comment></comment><comment><USER28> The word IBM feels conspicuous.

</comment><comment><USER29> (Poetry) So does the time arrow marches forward unstoppably?

</comment><comment><USER30> TLDR instead of traveling through time they just ┬──┬ ノ(° -°ノ). In a simulation.

<comment><USER31> This is the best TLDR ever written.

</comment></comment><comment><USER32> Does this mean we can make Pluto a planet again??

</comment><comment><USER33> *localized

</comment><comment><USER34> Is this like Wheeler's Delayed Choice experiment?

<comment><USER7> No. This is a quantum system that evolves from a state A to a state B, then is exposed to a very specifically designed potential field that causes it to evolve back to state A. It's actually not that mysterious nor unexpected, just an impressive technical achievement.

For an accessible description of what is going on here see:

[http://blog.rongarret.info/2014/10/parallel-universes-and- ar...](http://blog.rongarret.info/2014/10/parallel-universes-and-arrow-of- time.html)

<comment><USER35> I appreciate the link, but fair warning to others - it has a prerequisite of reading three other postings for complete comprehension per the article.

<comment><USER7> Three? I only count one. (BTW, I'm the author.)

But yes, you do need to understand entanglement and how it relates to measurement before you can understand time reversal. There's a reason QM has a reputation for being a difficult topic.</comment></comment></comment></comment>


Iranians Upset Over Google Reader (A Bigger Deal Than You Think) - <AUTHOR> http://techcrunch.com/2011/10/25/iranians-upset-over-google-reader-changes/

<comment><AUTHOR> Beyond the obvious point I submitted this because I think there's an important issue here. Google's way of software development relies heavily on analytics. So they look at how much feature #1 and feature #2 are used and make decisions based on that.

The problem with that is it doesn't tell you how important each feature is to the people using it. So while feature #2 might be used 20 times more than feature #1 it's possible feature #1 is life changingly important while feature #2 isn't something people would miss.

<comment><USER2> That's an excellent point, and should sometimes be considered in our decisions.

I'm guessing if such a conversation happened at Google, the end would be something like "Can the degree of life changing importance be measured? No? Make the change."

</comment></comment><comment><USER3> I think there is a misunderstanding here. Reader is not going away and it will still be a feed reader. As for encryption, Reader currently doesn't use SSL, G+ on the other hand does so that's an improvement. The changes if I understood correctly are that Reader will get an interface overhaul and it's social capabilities will be outsources to G+.</comment>


The Battle for Amazon HQ2 Was a Con - <AUTHOR> https://medium.com/s/no-mercy-no-malice/no-mercy-no-malice-hq2-and-3-82bf3c776f9c <comment><USER2> In full hindsight, the sheer efficiency of the HQ2 gambit is striking.

It was obvious from the beginning that framing it as a "competition" between a short list of cities was a ploy to make gullible politicians bid against one another while Amazon waited to see who could offer the most enticing deal.

What is perhaps less obvious is that now everyone who participated has shown their hand: Amazon knows exactly what concessions each city can afford. With their HQ2s "selected", Amazon can now offer far less glamorous satellite offices or warehouses to those cities and drive a murderously hard bargain doing so.

In one fell swoop: a free media circus, leverage on every location they might want to move into in the future, and heaps of public funds, in exchange for opening the offices Bezos already knew he wanted.

<comment><USER3> Why would you ever enter a negotiation if you don't know what you want ? You're most likely to injure yourself. So sure, Bezos' didn't make mistake #1 people make in negotiations. Google "bafta", "negotiation maximum pain", and start there for what you need to know before you buy as much as a loaf of bread. And yes, I have in fact managed to negotiate down the price of bread in a Supermarket. I would suggest you try too, just to show yourself that it's possible.

Amazon only grew because of the interstate commerce Sales tax exception. Essentially Amazon grew only because states couldn't tax it. Only the Federal government got money from them. Amazon is a creation of the Federal government (using a rule, ironically, Democrats and even Bernie Sanders voted FOR, not against. The Federal government really wanted to create an Amazon like company, and so they provided this advantage, and Bezos crushed it. That's what happened. Amazon is not a bookstore, it isn't even a store or warehouse or technology firm, it's a effectively a government hedge fund)

Look at Bezos' background. Is he a librarian ? A book seller ? He's a wall street investor (started as an engineer actually, but he was working quite the time as a speculator by the time he founded Amazon). He's a financial engineer, would perhaps be the best description. He will innovate, but he realizes that his innovations are about taxes, prices, trading and moving opportunities around. They're very much not about products, books, hosting, ... or any of that.

So last year the Federal govenrnment took away his tax advantage over his competitors (at least Walmart). So you can bet your bottom dollar that 12 out of every 24 waking hours of Bezos' time were spent figuring out how to get that back. This seems to have been one answer (I seriously doubt he has only one trick going).

<comment><USER4> Hard response to up or downvote. It started out upvote worthy and ended up downvote ranty, so I am just commenting here of my dilemma instead.

</comment></comment></comment><comment><USER5> >Did Bezos think no one would notice?

the obvious answer to this here is that no, they expected people would notice. but they made the call that there wouldn't be any consequences. and they were probably correct.

</comment><comment><USER6> "Of more than 400 metros in the US, five account for over 20% of the growth. And, you guessed it, two of those five are DC and NYC."

</comment><comment><USER7> I see lots of people claiming this, but haven't seen anyone that can point to their articles published before the announcement predicting it.

<comment><USER8> Do a google search for "articles predicting DC and nyc would win amazon" and you'll get results going back at least to September 2017. Folks had NYC and DC at least in the final four, if not outright winners. A sample:

[https://money.cnn.com/2018/01/19/technology/business/amazon-...](https://money.cnn.com/2018/01/19/technology/business/amazon- hq2-reax/index.html)

[https://amp.businessinsider.com/amazon-hq2-will-be-new- york-...](https://amp.businessinsider.com/amazon-hq2-will-be-new-york-or-dc- scott-galloway-predicts-2018-2)

<comment><USER9> That's not really evidence, as there are articles like this for many combinations of two cities.

</comment></comment></comment><comment><USER10> I mean, yes, it probably was. But this article offers precisely zero to substantiate that opinion beyond our own private speculations of same.

</comment><comment><USER11> Whether it is or isn't, does it matter? 50K jobs will still be created according to the news.

<comment><USER8> I think you are missing the point. Those 50k jobs were going to en up in NYC and DC no matter what. The "competition" was used to get those two metro areas to offer buckets of money to a company that does not need said dollars. That money could have been put to much better use.

It was sleazy AF.

<comment><USER7> If one of the cities had refused to offer incentives, even if the article's premise is correct I think Amazon would have gone with the other only.

<comment><USER8> And that would have been fine. NY could get much more bang for their buck then giving it to Amazon by — for example — investing it in the subway system.

<comment><USER7> I don't they could get anywhere close to a 10X return on investment that way

</comment></comment></comment></comment></comment><comment><USER12> _Ends up Blaze was just playing the field to extract resources, and use the grift to extract every penny from the studio he knew he would ultimately pick? We'd assume that Blaze lacks character._

Huh? Since when is initiating a bidding war immoral or lacking in character?

A party might come up with an attractive offer you never considered or thought possible. And even if you knew you wouldn't take their offers, it is rational and logical to get the best deal you can with something that is expensive and one-off like this.

<comment><USER13> When all of your profits come at the expense of the local residents who don't get a vote on the matter, I think it's a lot stronger case for immorality. A moral business has limits at which it drives for profit. I'm not sure where I stand on it myself, but the bidding war itself is not the moral problem, it's the context of the bidding war. I certainly don't view Amazon positively for doing it. At its core, this is Amazon profiting at the cost of American citizens. If every corporation did this, America would take quite a big hit. I would love to see the practice of making such a bidding war become illegal.

<comment><USER14> "who don't get a vote on the matter" -> They elected the representatives that they trust to make these decisions; that's representational democracy, the cornerstone of most of the world's countries.

To change it, you as a citizen need to demand better of your politicians.

Amazon's not the problem; they're just doing what's best for their shareholders, which is the whole point of a corporation. It's the government that needs to be held accountable for this situation; they're the ones going along with the bidding war - your suggestion of such a bidding war being made illegal is definitely a start.

<comment><USER13> In today's America, demanding politicians only goes so far and I would say its one of many broken parts of our system. You can say that I "as a citizen" should do X but the reality is that citizens have lost control of their government and have for some time now. I personally believe that representational democracy is very flawed and would love to see a return to more direct democracy.

Amazon isn't the source of the problem but a company that exploits the problems of others for their gain is not a not moral company in my book. And of course there is a spectrum here as it's impossible for law to match morals, but for a company in such a large and good position to do this without need is a notable action from a moral perspective. So no, Amazon is not the problem, but given that no one has really quite done this at this scale, they basically created the problem in the first place and Amazon deserves scrutiny and blame for that 100%.

<comment><USER12> Petitioning local governments for incentives to build factories/business related enterprises has been around for a while. Pretty much every major sports team ownership group goes for subsidized stadium construction.

<comment><USER6> And all of those processes have been widely criticized for being bad deals that hurt taxpayers. Just because Amazon is playing a long-established game doesn't mean that game isn't crooked, and that they shouldn't be criticized for indulging in such a farce, especially when they have the wealth and resources to do otherwise.</comment></comment></comment></comment></comment></comment>


Bristol reveals plans to pedestrianise historic centre in Covid-19 revamp - <AUTHOR> https://www.theguardian.com/uk-news/2020/may/21/bristol-reveals-plan-to-pedestrianise-historic-centre-in-covid-19-reforms <comment><USER2> I'm a Bristol native (though I grew up in the Italian city of Milan) and I absolutely love the place, particularly the Old Centre this article refers to.

Whenever I go back I make it a point to stay well within the Old Centre area, usually just a block from St Nicholas' Market (which is a truly beautiful area).

When all of this is over I look forward to going back. I recommend anybody who gets a chance to do so to have a visit. It's a criminally undervalued destination.</comment>


Ask HN: How do you keep a client from stealing your excel spreadsheet? - <AUTHOR>

We have developed a financial model in excel worth in the neighborhood of $75-100k and many people in our industry have similar financial models.<p>How would you keep it from being stolen if you wanted a client/employee to use it without taking it with them or using a copy on their own PC? Is there a way to allow use of an excel model without ownership? <comment><USER2> use www.cellmaster.com.au (disclosure I am the founder) At the moment it is free for low volume usage.

These also look like they would do what you want, maybe spreadsheetconverter depends on your needs:

BaseCase.com

stoic.com

www.spreadsheetconverter.com

www.smartsheet.com

[http://www.forguncy.com/](http://www.forguncy.com/) (Japanese)

www.spreadsheetweb.com

Please tell me more. Details of my email on www.cellmaster.com.au.

P.S. I also like ethercalc as spreadsheetguru suggested - but think many of above would be less work.

</comment><comment><USER3> implement a DRM mechanism. One way is to build an authentication server, log against a license, and rotate licenses as needed if you find curious activity. This is not a new problem and has been done previously. You may need to get creative with the code. I'm assuming that your model is quite visible for someone to reverse engineer by looking at VB project in Excel. You need to find a way to hide it as well.

<comment><AUTHOR> Not going to lie, sounds like brain damage, especially for super non-technical real estate folks (I am one).

What do you think about a Citrix/Virtual Machine where the client could use the excel sheet over internet, play with it, without any connection to the outside world (ie email, dropbox, internet). Owner of the document would have full ability to download and edit, but client would only be able to edit and save within the virtual machine... Overcomplicating much?

<comment><USER3> sure - I understand. I can't comment on Citrix/VM setup. Once they have access to the document, they will be able to screenshot it. etc.

Sounds like you need to keep it simple. I did a google search for "excel document drm solutions". You'll need to investigate all solutions for yourself, but looks like there are plenty off the shelf solutions.

</comment></comment></comment><comment><USER4> If it's worth that why hasn't it been converted to something easier to control...or is that what was paid to develop it (not actual value)?

<comment><AUTHOR> Functionally, that is what would have been paid by someone else to develop it. It was built in house.

Honestly, us real estate folks are scared of what they don't know. Excel is familiar so converting it to our own software or web platform is not going to happen.

I just figured there would be a solution or service where users could use an excel document in a neutral place where the owner of the document could let people use the functionality of the document without stealing the source. Its like every excel document, once sent to someone else, is functionally open- source.

</comment></comment><comment><USER5> you implement it on the serverside as an API or webapp that you sell as a service. There are many ways of doing this, for example resolver one, or ethercalc. In the olden days would have probably written a webapp that interfaced with excel directly using the COM APIs, but that went aggainst MSFT's EULA.</comment>


Ask HN: VPS - Where should I go? - <AUTHOR>

I am looking for a good VPS (Virtual Private Server).  I just tried 1and1.com's 3 month money back VPS II - and found it to be slow, unresponsive (SSH / WWW connections literally took seconds).<p>Can someone recommend a good place for a VPS that would give me a quick and responsive server?  Something I can run ubuntu on, manage security and updates. <comment><USER2> I'm happy with linode. Decent prices, good service.

</comment><comment><USER3> Probably to searchyc.com

<http://searchyc.com/%2522ask+hn%2522+vps>

I like Linode FWIW. Bandwidth pooling, good API, good resources, mostly-idle (hand-waving) quad-cores, 5 data centers, a very responsive IRC channel and forums, ability to grow/resize a linode at any time, etc.

<comment><USER4> the CPU advantage linode has over myself and (I believe) slicehost is that linode is using QPI xeons (Nehalams, 55xx chips) which are significantly better than the opterons the rest of us use for certain workloads (for other workloads, though, they are about the same)

Out of curiosity (I'm considering cloning the API slicehost set out for others to clone) how does the linode API compare to the slicehost API?

<comment><USER3> I am sorry but I am not familiar with the Slicehost API.

Since no one asked, I haven't really truly considered Slicehost an option for my projects. When I started researching the various options, Linode looked 2nd best by the numbers for VPS. prgmr.com looks the best but I am not sure I'd bet the farm on such a tiny operation. Slicehost is of course similar to Linode but it seems Linode gives you more bang for your buck and has nothing to do with Rackspace which in my limited foray into this hosting world seems like a good thing (but what do I know?).

<comment><USER4> well, personally, I think betting the farm on any single external service provider is a really bad idea, but then, like you said, I'm not really in a position to have people bet their farm on me so it's kinda self-serving to say that.

For my education, how much of your hesitation is that it's a tiny operation, and how much of it is that the prgmr.com tools for creating/resizing are non- existent?

<comment><USER3> This is just my $0.02. Everything I've heard about prgmr has been positive. For me, it was that it was a tiny operation. I've been burned by this myself for consulting gigs ironically enough.

</comment></comment></comment></comment></comment><comment><USER5> This is not HN material. Direct this question to <http://serverfault.com/>

Other than that, here's a list that should do you good: <http://djangofriendly.com/hosts/>

</comment><comment><USER6> If you need backups by the company themselves that can be used to deploy more instances I would go with slicehost, otherwise linode. Slicehost has more features like a handy iphone app, but linode is cheaper and at least in my limited testing, performs better.

<comment><USER7> Linode have an iphone app now too, I haven't used it but do recommend their VPS services.

</comment></comment><comment><USER8> Where are you? <http://www.bytemark.co.uk> are good in Europe.

<comment><AUTHOR> Toronto, Canada

</comment></comment><comment><USER9> linode, slicehost, rackspace cloud

</comment><comment><USER10> slicehost</comment>


Everybody Dance Now [video] - <AUTHOR> https://www.youtube.com/watch?v=PCBTZh41Ris <comment><AUTHOR> Related paper: [https://arxiv.org/abs/1808.07371](https://arxiv.org/abs/1808.07371)</comment>


Google to acquire Motorola - <AUTHOR> http://googleblog.blogspot.com/2011/08/supercharging-android-google-to-acquire.html

<comment><USER2> I'm sorry, was it really necessary to remove the "Mobility" part of the original post for the title? This isn't an acquisition of the whole Motorola company...

<comment><USER3> One thing I find interesting is that nowhere in the post itself does Larry Page (or whatever flack wrote this for him) say "Motorola Mobility". The only place that construction appears is in the title of the blog post.

<comment><AUTHOR> Actually, this was the reason the title is what it is. I didn't intend to mislead, I just didn't read the title and made one up from the article (clearly I did read it, but not consciously).

</comment></comment></comment><comment><USER4> More discussion can be found here:

<http://news.ycombinator.com/item?id=2886342>

</comment><comment><USER5> Motorola Mobility. The other half of the 2 way split, Motorola Solutions, remains independent.

</comment><comment><USER6> Who needs innovation anymore when you can just copy your competition feature- for-feature, subsidize with ad revenue, give it away for free, and acquire patent protection?

<comment><USER7> It seems to me like you want to suggest, that Google is copying Apple here. (If not, ignore this post.)

I remember using a Nokia smartphone back in 2004. It already had the application icon grid, colored icons, it had maps, it had navigation, a web browser, email and an mp3 player. The quality of the software was poor, the hardware was cheap and underpowered, there was no multi-touch and, of course, the network was slow and too expensive to actually use.

Sure, Apple took the smartphone and actually turned it into a mobile computer that was a pleasure to use. Also the timing was right.

Google did not add as much value as Apple to the state of the art. But Apple certainly copied older smartphones feature-for-feature as well, then they made this into a great experience.

But to suggest that now Apple has somehow the exclusive right to produce phones that are not on the level of smartphone from 2006 and older is just wrong.

</comment></comment><comment><USER8> One thing that beats me is how are they going to assert their position about openeness when talking to partners like HTC and Samsung? What credibility does google have when in past they have already tried to restrict access to newer android builds from partners who do not integrate with their apps.

As a partner, I'd be very weary of dealing with them. Google has a huge job of winning those guys back.

What they have to realize is that Android did not really win on being "android" it won because it was a "cheaper iphone" made by a lot of hardware partners. That filled the gap while iphone was content being exclusive. Now iPhone available with both major vendor and most other countries, its going to be a tough road.

</comment><comment><USER9> class</comment>


Lessons in Electric Circuits - <AUTHOR> http://www.ibiblio.org/kuphaldt/electricCircuits/index.htm <comment><USER2> Is there any good electronic elearning tutorial sites like codeacademy or codeschool but for electronic circuits?

<comment><USER3> Not elearning, but if you need a basic intro to electronics I would recommend the Forrest Mims books.

<comment><USER4> Which one to start with?

<comment><USER3> _Getting Started in Electronics_ is good, though I think there might even be a more basic one depending on how much you already know. I think they give a good overview with fun projects and get you to the point where you can find more advanced materials on your own and even come up with your own projects.

</comment></comment></comment></comment><comment><USER5> All About Circuits (www.allaboutcircuits.com) is an expanded version of this open-source textbook.

It looks like any corrections and additions made on All About Circuits feed back to this source too, but AAC has a slightly more web-like layout and links to additional materials (forums, worksheets, video lessons, etc.).

</comment><comment><USER6> See also Socratic Electronics, also by Kuphaldt

[http://www.ibiblio.org/kuphaldt/socratic/](http://www.ibiblio.org/kuphaldt/socratic/)</comment>


I Had to Fire a Client Today - <AUTHOR> https://medium.com/@twhitter/i-had-to-fire-a-client-today-aed9d79c5b80

<comment><USER2> I read Clients From Hell. Clients not paying is every day stuff. Have you submitted this there?

[http://clientsfromhell.net/](http://clientsfromhell.net/)

<comment><AUTHOR> I've never read it until now. Some hilarious stuff...Thanks!</comment></comment>


How to Install Tensorflow GPU with CUDA 9.2 for Python on Ubuntu - <AUTHOR> http://www.python36.com/how-to-install-tensorflow-gpu-with-cuda-9-2-for-python-on-ubuntu/ <comment><USER2> Ah yes, python36.com. Now that's not Python 3.6, that's a domain registered by someone who wanted to hikack some seo juice (joose?).

It looks like they didn't register python37.com though, which is probably a big deal as Python 3.7 is in beta.

</comment><comment><USER3> To add on top of the tutorial, it's recommended to compile with AVX, SSE and FMA instructions enabled if you are using a modern Intel chipset. It has a pretty big boost for calculations that needs to be done on the CPU.

The pip version of TF does not come with AVX and FMA for some reason, so this is one of perks from compiling from source

<comment><USER4> It seems like Tensorflow 1.8 with CUDA 9.2 performs up to 37% faster when compared to earlier versions of Tensorflow as described in the post. (link below) [http://www.python36.com/benchmark-tensorflow-on- cifar10/](http://www.python36.com/benchmark-tensorflow-on-cifar10/)

<comment><USER5> I've been playing around with a couple DL frameworks recently, so was wondering, what is the performance tradeoff between what you mention and PyTorch? Is it significantly different? Because I enjoy the pyhonic "style" of PyTorch way more than the graph creation/precomputation method of TensorFlow.

</comment></comment></comment><comment><USER6> sounds like big news

<comment><USER7> Contains some buzzwords though</comment></comment>


Ruby help on Jailbroken iOS - <AUTHOR>

I'm having issues with Ruby on iOS. Any gem command fails. If I try to gem update:
mobile$ gem update
Updating installed gems dyld: lazy symbol binding failed: Symbol not found: __OSSwapInt16 Referenced from: /usr/lib/ruby/1.9.1/arm-darwin9/socket.bundle Expected in: flat namespace
dyld: Symbol not found: __OSSwapInt16 Referenced from: /usr/lib/ruby/1.9.1/arm-darwin9/socket.bundle Expected in: flat namespace
Trace/BPT trap: 5
What's interesting is ruby -v shows 1.9.2:
mobile$ ruby -v
ruby 1.9.2p0 (2010-08-18 revision 29036) [arm-darwin9] Any ideas on how to fix? I've tried removing Ruby package via Cydia and reinstalling but it's the same. <comment><USER2> Stack Overflow, perhaps? This is not the place for that sort of thing.

<comment><AUTHOR> Thank you for your useless attempt to be a jerk.

If this is not the place for "that sort of thing", why are there various "Ask HN" type posts a la <http://news.ycombinator.com/item?id=4403897> ?

My apologies for feeding the trolls here, but it seems HN is a hostile and destructive environment.

<comment><USER2> Number of "Help me with my Ruby code" posts that get constructive answers on HN: Zero.

Number of "Help me with my Ruby code" posts that get constructive answers on Stack Overflow: Nearly All.

There's a place for everything. Don't accuse me of being a jerk for pointing that out.

The kind of content that's best suited to Hacker News is something that has general appeal to people in the development, start-up, or general technical scene. Your specific problem, no matter how important it is to you personally, is not that sort of thing.

Stack Overflow is specifically designed to answer these sorts of questions. Why are you throwing a fit when that's your best option?</comment></comment></comment>


An open source tool for planning sustainable public bike paths - <AUTHOR> http://geo8.webarch.net/master/ <comment><USER2> Unfortunately in the US, bike paths have often tended to occur not because of sustainable planning for bicycles, but because people have tended to favor gas-guzzling cars over railways, the railway tracks fall into disuse and abandonment, and then get paved over as bike paths.

What would be much nicer for the environment is having both railway AND bicycles. Trains and bikes complement each other amazingly well; in much of northern Europe this combination is a perfect way to get around.

Having bikes and no trains sucks because you can't just cram bikes onto buses and cars, so bicycling becomes a hobby exclusively for the athletically fit who are determined to cycle long distances and carry repair tools wherever they go.

Having trains and no bikes sucks because once you get off the train you can't get where you need to.

<comment><USER3> > in much of northern Europe this combination is a perfect way to get around.

Haha what? SJ (the Swedish railway company) doesn't allow the transport of bicycles in any of their trains. At least in southern Sweden you have the Öresundståg where you're allowed to take the bicycle with you.

I also like the combination of bicycle+train, but you can get a bicycle rack for your car and lots of long distance bus companies offer to take your bicycle with you.

<comment><USER2> Oh that's interesting. I'm speaking mostly from travelling in Netherlands, Switzerland, France, and Germany, all of which allow bicycles on most regional train services (perhaps with needing to buy a bike ticket).

</comment></comment></comment><comment><AUTHOR> The full paper with more detail on the model used to and its applications is at [http://arxiv.org/abs/1509.04425](http://arxiv.org/abs/1509.04425)

</comment><comment><USER4> Some very nice work with the mapping visualization although I am not too sure how to use the tool. Perhaps an intro or walk through might help?

</comment><comment><USER5> What is the source of the map. Maybe it is just refreshing to me being so familiar with the big guys, but I find it super appealing.

<comment><USER6> As with almost any cool map you'll see these days, it's OpenStreetMap, via CycleStreets specifically.</comment></comment>


Mathematical View of the New Pound Coin - <AUTHOR> http://seanelvidge.com/2016/11/new-pound-coin/ <comment><USER2> Since the page is inaccessible right now, here's the tl;dr (though it's not long at all):

The UK's new £1 coin has 12 sides. That makes it impossible for it to be (like the 7-sided 50p and 20p coins) a shape of constant diameter, which might make it roll less well and make things harder for the makers of vending machines.

When OP heard that the new coin was going to be 12-sided, he wrote to the Royal Mint. When the final design came out, it turned out that they'd taken this objection into account but found that a 12-sided coin with curved sides and rounded corners rolls well enough. Very good, but OP would have been happier with an odd number of sides. The end.

(Is the constant-diameter property actually relevant to vending machines? It seems to me that unless you're trying to fit the coin down a "tunnel" of absolutely minimal size, what matters is how close it is to constant _radius_ \-- i.e., how nearly circular -- and constant diameter is a red herring.)

<comment><USER3> > Is the constant-diameter property actually relevant to vending machines? It > seems to me that unless you're trying to fit the coin down a "tunnel" of > absolutely minimal size

A lot of cheap coin-op mechanisms put coins through an exactly sized tunnel as first step, so while it's probably not critical, it would be nice to have the coins be constant diameter as now you either need to configure your coin acceptor to be more slack or install a new one altogether.

</comment></comment><comment><USER4> But why not make the whole coin round?

<comment><USER5> Different shapes make for easier identification without looking at the coin (good for the blind, people trying to find a coin in a wallet, etc...), and are harder to fake.

It is also, apparently, a reference to the shape of the old threepenny bit.

<comment><USER6> Which is what a pound will be worth post-Brexit.</comment></comment></comment>


Why Developing for Firefox is Torturous  - <AUTHOR> http://log.nadim.cc/?p=116

<comment><USER2> This is an interesting take that I hadn't really heard before.

I find the complaint about the JS engine being slow interesting. I was under the impression that Mozilla had largely closed the gap, but performance differences still existed (but possibly not all in Google's favor). I wonder if he's developing on Chrome, and thus implicitly optimizing for it, and noticing the problem areas where the engines don't have matching characteristics? Then again, maybe Mozilla still has some JS engine areas that really need improvement.</comment>


The original builder of R2-D2, Professor Tony Dyson, has died - <AUTHOR> http://www.bbc.com/news/entertainment-arts-35724496 <comment><AUTHOR> Link to the RHOF R2-D2 induction page: [http://www.robothalloffame.org/inductees/03inductees/r2d2.ht...](http://www.robothalloffame.org/inductees/03inductees/r2d2.html)</comment>


Show HN: Poica – Algebraic data types and type introspection for pure C - <AUTHOR> https://github.com/Hirrolot/poica <comment><USER2> This is ... wild. Usually these things explode in size when compiled, require an external preprocessor, and/or heavily lean on system calls. This does none of those things.

<comment><USER3> Doesn't this require an external preprocessor? The Boost Preprocessor

<comment><USER4> No, boost/preprocessor is a library that offers metaprogramming primitives for the standard C/C++ preprocessor

</comment></comment></comment><comment><USER5> Neat. I wrote a similar header only library a long time ago just for sum types, so it's a little more limited but works for C89 or later IIRC:

[https://github.com/naasking/libsum](https://github.com/naasking/libsum)

</comment><comment><USER6> Unfortunately none of the examples contain malloc, whilst I'm curious as to whether the pattern matching works with heap allocated object. The binary tree example only has statically defined tree, which blows up into lots of code in assembly.

</comment><comment><USER7> So in this case the connection to algebraic data types is that they provide static type checking for unions _as well as_ structs in C along with type introspection which is novel.

The linked article explaining the whys and wherefores of ADTs ([https://codewords.recurse.com/issues/three/algebra-and- calcu...](https://codewords.recurse.com/issues/three/algebra-and-calculus-of- algebraic-data-types)) has hit the front page of HN twice now!

</comment><comment><USER8> I wonder whether this interacts cleanly with Cello, GTK+, or other "object- oriented" C libraries. It certainly is a nice presentation, if a little baroque.

</comment><comment><USER9> wow that actually looks pretty clean</comment>


Joshua Schachter Launches Newest Tasty Labs Project, Skills.to - <AUTHOR> http://techcrunch.com/2012/03/28/joshua-schachter-launches-newest-tasty-labs-project-skills-to/ <comment><USER2> Hooray!

Disclaimer: that's me!

<comment><USER3> Hey joshu, are you planning on building a people's search with reputation built in?

<comment><USER2> I dunno. We are figuring it out as we go along.

I always thought people search was for searching by name?

I want to do reputation search with people built in.

<comment><USER3> OK. It makes sense! Had a play with it today and saw more people mentioning on Twitter.

Good luck!</comment></comment></comment></comment>


LHC spots particle that may be new form of matter - <AUTHOR> http://www.newscientist.com/article/dn25402-lhc-spots-particle-that-may-be-new-form-of-matter.html#.U0mBHObqe0a <comment><USER2> Since 2008 researchers at Belle in Japan found hints of a four-quark particle. Those hints were confirmed.

"This reinforces the 5.1σ (4.7σ) rejection of the 2+ (2− ) hypotheses previously reported by the Belle collaboration, and confirms the 3.4σ (3.7σ) indications from Belle that 1+ is favored over 0− (1− )."

Belle collaboration, K. Chilikin et al., Experimental constraints on the spin and parity of the Z(4430)+ , Phys. Rev. D88 (2013) 074026, arXiv:1306.4894.

"The cost [...] has been evaluated, taking into account realistic labor prices in different countries. The total cost is X (with a western equivalent value of Y)" [where Y>X] source: LHCb calorimeters : Technical Design Report ISBN: 9290831693 [http://cdsweb.cern.ch/record/494264](http://cdsweb.cern.ch/record/494264)

or: "1the western equivalent value is 1'390 kCHF. 2the western equivalent value is 5'450 kCHF" [http://lhcb.ecm.ub.es/spd/spd/General%20information/spd_cost...](http://lhcb.ecm.ub.es/spd/spd/General%20information/spd_cost_tdr.pdf)

<comment><USER3> Dead link

</comment></comment><comment><USER4> New form of matter seems a bit linkbaity... It's a highly unstable particle made of 4 quarks, kind of like a meson (which is a quark/antiquark pair).

<comment><USER5> > It's a highly unstable particle made of 4 quarks, kind of like a meson > (which is a quark/antiquark pair).

I thought the new particles were cool because they don't follow the color charge analogy, whereas mesons do follow the analogy?

<comment><USER6> The posible colors combinations of the mesons are red+antired, blue+antiblue and green+antigreen. The color+anticolor are not fixed, they "constantly" change. (Actually, any linear combination of the pairs is posible.) [http://en.wikipedia.org/wiki/Quark#Strong_interaction_and_co...](http://en.wikipedia.org/wiki/Quark#Strong_interaction_and_color_charge)

There are some abstract algebraic properties of the particles and these properties produce the color rules.

With 4 quarks the only possibility is a mix of 2 quarks (with colors) and 2 antiquarks (with anticolors). For example red+antired+blue+antiblue.</comment></comment></comment>


Ask HN: How to overcome your skill plateau as a programmer? - <AUTHOR> Hi all,
I've been working professionally as a software developer for 3-4 years, and am currently in a large engineering organization (not a FAANG but a financial firm). While the day-to-day work I do is "coding", little of it has been on projects where I feel I've come out more knowledgeable about building good software.
My current struggle is having recognized the __large__ gap between writing "code that works" and writing programs that are stable, maintainable, and extensible. As much as I've been aware of it, I still find myself writing more of the former than the latter. Work projects feel limiting on how much I can explore new ideas / re-think architecture and design philosophies, while personal projects have felt mediocre and any attempt at writing good code has come off as "premature optimization".
I love programming, but this skill/understanding plateau has left me a bit burned out recently.
Have any of you ever experienced something similar after a few years in the industry or as professionals? How did you deal with it, and what were some actionable steps that helped you overcome it?
I know some of you on HN have been programming for decades, so I'm curious to hear what were the moments you were able to take and become better engineers.
Thank you for any insights you may have! <comment><USER2> Side projects. You can try any new modern framework you want with a side project.

Also, read the code of good projects on Github.</comment>


Dell XPS13 Laptop – Cool Tools - <AUTHOR> http://kk.org/cooltools/dell-xps13-laptop/ <comment><USER2> I've had the XPS 13 for almost a year now for home use and it's been great. The form factor is pretty much perfect for me and it looks super sleek. Performance for coding is good, and even some games like Rocket League work pretty well. I had a 13" inch Air previously, and while the Dell trackpad is not quite as good, I much prefer the XPS.

The only downside that should put people off is the coil whine. Mine is thankfully present only when compiling large projects, but some people do report a constant whine. Also, I had to get the larger resolution screen which means you need to scale your desktop to be able to read anything. Another trade off is the 2x TB connection, but apparently it works OK for even external GPUs, something I've considered.

All in all, it's pretty well rounded for it's size and I'd recommend anyone looking for the form factor to consider it.

</comment><comment><USER3> I got one a few weeks ago and it's great. I love the form factor and it packs some good punch and works great on Ubuntu (17.10). However, the infamous and almost constant "coil whine" is a bummer :-|</comment>


Radiohead's Thom Yorke says Google, Apple have made music 'worthless' - <AUTHOR> http://www.theverge.com/web/2013/2/28/4039732/thom-yorke-says-google-apple-have-made-music-worthless <comment><USER2> I don't know if Google and Apple are the ones to blame here. The record labels seeking to systematize pop music (as they always have, but have apparently perfected in recent times) are the ones who have destroyed music. Google and Apple created the marketplace, sure, but they've also lowered the barriers to entry for independent artists to compete with their "clearly superior music".

It's an age old argument, if art is so valuable, then why can't we get more value out of it? If Ke$ha and Bieber are so devoid of value, then why do they bring so much value to their owners?

But I'm not trying to argue about "what is art" and "what is good art". There is a distinctly big difference between good and bad art, and the lack of recognition for the good stuff in favor of the bad stuff is a matter of priorities on behalf of the artists. Good artists are art geeks. As PG wrote in Hackers and Painters, if they really wanted to be more popular, they would work at it. Artists who claim they wish they were more popular are mistaken: they would rather be principled and unpopular than popular and unprincipled.

So I understand why Yorke is upset. But I don't think Yorke understands why he will continue to be upset.</comment>


Inside the 76477 Space Invaders sound effect chip - <AUTHOR> http://www.righto.com/2018/05/inside-76477-space-invaders-sound.html <comment><USER2> This is a fascinating article. Footnote 8 is an especially fascinating insight;

      > One puzzling feature of the shift register is that there is no wiring between the stages!
      > How do bits get from one stage to the next? Did the chip have another layer of wiring that wasn't in
      > the photos? Was there some sort of hidden connection? Eventually I noticed that there wasn't an isolation
      > ring between the stages—a silicon barrier that separated most I2L circuits. Without this isolation ring,
      > an "invisible" PNP transistor exists between the stages, apparently allowing one stage to flip the next
      > stage to the right value. Each shift-register stage is constructed from two NAND-gate latches. When the
      > clock is low, the first latch is forced into an indeterminate state. When the clock goes high, the latch
      > ends up as 0 or 1 based on the bias it receives from the previous stage through the "invisible" PNP
      > transistors. Thus, the latch becomes edge-sensitive since it will change right on the clock's rising edge.
      > I found a paper ("Injection-Coupled Synchronous Logic", 1978) that describes a similar technique for an I2L
      > shift register9, so I think this is the right explanation, even though the circuit seems a bit sketchy.

<comment><USER3> A direct link to the footnote, as the above is unreadable. (Hint: don't use code formatting for quotes. It is semantically wrong and is unreadable on many devices.)

[http://www.righto.com/2018/05/inside-76477-space-invaders- so...](http://www.righto.com/2018/05/inside-76477-space-invaders- sound.html?m=1#fn:connection)

<comment><USER4> Semantically wrong or not, it's all the HN developers have chosen to give us for blockquoting. That's not the users' fault.

For mobile, it helps if you manually truncate lines, like so:

       One puzzling feature of the shift register
       is that there is no wiring between the stages!
       How do bits get from one stage to the next?
       Did the chip have another layer of wiring that
       wasn't in the photos? Was there some sort of
       hidden connection? Eventually I noticed that
       there wasn't an isolation ring between the
       stages—a silicon barrier that separated most
       I2L circuits. Without this isolation ring,
       an "invisible" PNP transistor exists between

The site _is_ called "Hacker News," after all. Apparently that's because we're expected to, well, hack.

<comment><USER5> Italics are more readable.

<comment><USER4> And semantically just as broken.

Would it be that hard for the '1337 h4x04s at YC to support '>' blockquote markup like so many other forums?

<comment><USER5> So what's more important "semantic correctness" or having a readable post?

</comment></comment></comment></comment></comment></comment><comment><USER6> I definitely bought this chip and a bunch of pots and caps and twiddled with it. While I had a full sized Yamaha organ at home to make music with, being able to invent my own sounds was almost more satisfying. I'm definitely more an engineer than an artist, but continually struggle to keep focused on bringing projects to conclusion as they interfere with each other.

</comment><comment><USER7> For background, link to a discussion about the previous article [1] in the series: [https://news.ycombinator.com/item?id=14232499](https://news.ycombinator.com/item?id=14232499)

[1] [http://www.righto.com/2017/04/reverse- engineering-76477-spac...](http://www.righto.com/2017/04/reverse- engineering-76477-space.html)

<comment><USER8> Last year's article described the analog parts of the sound chip The new article discusses the digital circuits and how they are implemented using I2L logic, a competitor to TTL.

</comment></comment><comment><USER9> This reminded me I have two of this chip sitting in my parts bin, with nice little DIP format adapter boards even. It bugs me that I bought the chips ~18 years ago and still haven't done anything with them. My project queue needs some reshuffling. I should start making synth modules again.

Or I should find myself a Blacet Dark Star Chaos module. I should have bought one when I had the chance.

<comment><USER10> Lol, I have a couple lying around I had earmarked for building a midi interface for. Maybe my 8-y/o daughter will 'grow into them' as she is the only person in the house with any ability to play keyboards.

</comment></comment><comment><USER11> Brought back great memories. In the early 80s, I used this chip to build a small analog synthesizer. My dream was to build an Elektor Formant but had to settle for the 76477. But I learned a lot from that exercise

</comment><comment><USER12> [https://news.ycombinator.com/item?id=14232499](https://news.ycombinator.com/item?id=14232499)

Covered this material to some extent, there are quite a few comments. This is a different article though by the same author.

</comment><comment><USER13> Wow. I didn't realize that an analog synthesizer-in-a-chip was a thing that far back. Pretty remarkable. All the basics are there: oscillator, noise generator, filter, envelopes, lfo.

Although it's not quite everything. The VCF is for noise only, and there's no way to insert a filter into the VCO audio path externally. However, that pretty much defines the "chip tune" genre.

</comment><comment><USER14> Oh man - loved that sound! This will be a great read this weekend.</comment>


Kickstarter Should Do More to Protect Backers - <AUTHOR> http://www.inc.com/eric-markowitz/kickstarter-should-do-more-to-protect-backers.html

<comment><USER2> It annoys me that this is going to gain traction.

The only thing that should happen is that to fund something you have to click some really plainly worded opt-ins. But I'm betting regulators will get involved and remove this funding option for those who can't afford lawyers who specialize in crowd funding. Or can't then afford the discovery that will need to be done before they can request (crowd) funding.

[ I understand that I may lose all my money and that I have no recourse ]

[ I can afford to lose this money and not get anything in return ]

[ I understand that this is speculation and that only X% of projects deliver ]

</comment><comment><USER3> No, they should not.

What makes places like California vibrant is the entrepreneurial spirit, and that means risking capital on new ventures that could or not work.

In Europe(or Asia) is more like, If I put money you guarantee me that I am getting my money back, if not I will own you for the rest of your live.

You have to prove that you have experience being successful in order to success, but if you were you would not need them in the first place.

So nothing risky or new is made on Europe, if it is,it is bought by American companies like Skype. No risk, so no google, no Amazon, no facebook, no Microsoft, even having probably more educated people.

Kickstarter guaranteeing projects would mean no risk projects, and huge bureaucracy cost.

Today it is my work as a backer to evaluate projects, this is my responsibility, I don't want my big brother to do it for me.

<comment><USER4> Skype may be American now, but it's origins are clearly European.

"Skype was founded in 2003 by Janus Friis from Denmark and Niklas Zennström from Sweden. The Skype software was developed by the Estonians Ahti Heinla, Priit Kasesalu, and Jaan Tallinn, together with Friis and Zennström were also behind the peer-to-peer file sharing software Kazaa. In August 2003, the first public beta version was released."

Until it was acquired by eBay, it was a Luxembourgish company. I don't know how a company could be more European in origin.

<comment><USER5> I think he meant "European companies like Skype are bought by American companies".

</comment></comment></comment><comment><USER6> Remember that KickStarter is really about giving donations to cool projects ... not about investing in something, or buying a product. This is a really important niche, and they should _NOT_ be bullied into abandoning it.

If you want to buy a product with little-to-no risk, then go to Amazon.com. If you want to connect with individuals trying to do cool stuff, help them with their project, and _maybe_ get something in return, then Kickstarter is for you.

Certainly, Fraudsters and abusive individuals will always be drawn to tools like Kickstarter - and the team there need to be vigilant to keep blatant abusers away from the system.... A few will always get through. That is a risk that we all take ... but it is a risk that is well worth it for the service that Kickstarter provides to "fringe" projects that are simply too high-risk to attract conventional funding.

<comment><USER7> I strongly agree that Kickstarter's mission is great, and they should stick to that.

Perhaps they need some clearer warnings. Even with recent projects I see people complaining that they haven't got the items they've "bought".

I haven't seen much data to show how many Kickstarter projects there have been, broken down by successfully funded (or not) and delivered (or not) and out-right scams (or not).

</comment></comment><comment><AUTHOR> Follow up: The board game mentioned in the headline has been picked up by Cryptozoic Entertainment.

[http://www.cryptozoic.com/articles/cryptozoic-saves-doom- cam...](http://www.cryptozoic.com/articles/cryptozoic-saves-doom-came- atlantic-city-board-game)

Brings up the interesting question of how to handle KS projects that don't raise enough money to ship.

</comment><comment><USER8> Seriously, how could you fail to make a board game with over 100k?

He must've just had no idea at all about how to efficiently allocate the funds....

I mean I am on a team that raised like 170k to make a god damn video game and he can't make a board game with over 100. That makes no sense at all...

<comment><AUTHOR> Board games can often be more costly than video games because you have to manufacture (and ship) physical goods. I backed a purely pen and paper Kickstarter (Mobile Frame Zero) that had had some issues with shipping after they had printed all of the books, for example.

Video games do tend to require larger teams and longer development times though, so it's a trade off.

<comment><USER8> That is true but they should benefit greatly from scale, and this one has over 1000 backers to work with. Also their lowest tier is $50, and that is only for a paper and cardboard set.

</comment></comment></comment><comment><USER9> _The problem, as I see it, is that despite the company 's best efforts, many backers simply don't understand the risks involved in backing a project._

I think Kickstarter has done more than enough, but my prediction is that failures of this kind will not be tolerated by regulators. The US is very business friendly; considering limited liability and bankruptcy law. However on any front touching consumer protection the law often reaches too far, and punishes failure egregiously.

</comment><comment><USER10> From the article:

> _If you 're unhappy with the "reward," or if the project never gets created, > well, tough. Take it up with the project creator._

However, from the Kickstarter terms of service quoted directly below:

> _Kickstarter does not offer refunds. A Project Creator is not required to > grant a Backer 's request for a refund unless the Project Creator is unable > or unwilling to fulfill the reward._

I believe that the project "never getting[sic] created" would certainly be cause to deem the Project Creator as "unable ... to fulfill the reward."

</comment><comment><USER11> As far as I can tell, what makes this one different is that the "Project Creator" took up a boardgame which already had a following, roped in the artists and creators behind it, and then used their names and artwork to get the project funded.

Of course, they had no control over his actions. Ordinarily I'd look at the past output of the project creators to decide whether to fund a Kickstarter. Which is why funding Ryan North's choosable-path-adventure project was such a no-brainer.

So this particular instance is unusual, the guy behind it traded on the reputations of other people.

</comment><comment><USER12> Was chatting to some people about this today. One distinction I would make is the difference between getting the finished product as a reward or getting another incentive as a reward.

If I start up a kickstarter for a video game and I fail to deliver the video game I think that is fine. If I also fail to deliver something like tshirt rewards though that is plain mismanagement.

</comment><comment><USER13> wait, what? idiocy is its own problem... investing money is gambling, don't let the fact that we pin our entire economy on this fool you, its still basically a bad idea that only pans out because of luck.

</comment><comment><USER14> how many funded projects actually deliver something? i'd like to know the data...

<comment><USER15> Anecdotally, most. I've backed about 50 projects and none have failed to deliver, though plenty have been delayed.</comment></comment>


Share frequency on social networks - <AUTHOR> http://markmhendrickson.com/share-frequency

<comment><USER2> An aside: your blog's theme is gorgeous. Care to share?

<comment><USER3> I'll second that aside. As an aside to this aside, I noticed that the paragraph starting with "Higher frequency generally leads" is wrapped in closing </p> tags, as opposed to the <p> </p> (the things you notice when you highlight text as you read!)

<comment><AUTHOR> Oops -- fixed!</comment></comment></comment>


Beyond SSH Bookmarks - <AUTHOR> http://danielmiessler.com/blog/beyond-ssh-bookmarks <comment><USER2> Bash aliases only help you run the ssh command. They won't shorten scp or rsync commands, or version control checkouts. They won't even help if you want to pass a flag to ssh occasionally. So that's the downside of using bash aliases for this.</comment>


HN Smart - <AUTHOR>

After submitting one item today I found myself looking at my karma, something I couldn't care less until some time ago.
Then I also looked at ALL my submissions and comments and wondered if they would look good if I ever apply to YC.
I found myself worried about this: not being "HN smart".
For example longer posts are HN smart, they consistently get more upvotes than shorter ones. Talking/Linking about YC funded startups seems to be HN smart aswell.
Also, in the latest months I've always seen people complaining about the new userbase, which is not as good as the one of 2007-2008.
Again, I've been lurking since more than a year but I don't post often, and I don't usually post URLs since all the news I read is HN.
Can we say that the new userbase is less HN smart than the old one? Is that the point?
What's the "correct" feeling, if there's one? Mind your business helping others when you can or be HN smart at all costs trying to get others to upvote you when you'll introduce your startup and eventually look good on YC applications?
Genuine question, what was it like in the good ol' days?
Edit: fixed some grammar. <comment><USER2> What you describe as 'being HN smart' sounds like what would be described as karma whoring on Slashdot or Reddit.

And I think it's looked down on for a reason. The things that will get people to upvote you are not always the things that will look good on your resume. Often they break down after further scrutiny, and if someone is actually looking over your comments carefully (though who really has that much time on their hands.)

Just try not to be an ass, and if you don't think it meets HN standards, don't say it. I'd also say don't bother praising YC startups and the regular luminaries of the community - everyone else can do that easily enough on their own. But then I'm new here.</comment>


Ask HN: Fighting spam on Craigslist any alternative? - <AUTHOR>

I posted my macbook for sale on Craigslist (http://toronto.en.craigslist.ca/bra/sys/1290256034.html) and all i have been getting is scammers emailing me and asking me to ship it to Nigeria..
so wondering which sites do you guys use besides Craigslist for selling electronics?
Thanks <comment><USER2> Many sites suffer from this sort of spam. It's all a form of advance-fee fraud. I wonder if anyone has found an effective means to combat it -- logistical regression models, keyword filtering, etc.</comment>


Ask HN: What are the problems of each Web Language? - <AUTHOR>

I don't want to ask what is good about each language because everywhere you look each language is the best in some way. I want to know why each language is terrible and by Web Languages I mean those which are mature for Web Development, such as: PHP, Ruby, Python, Perl and any others you can think of. <comment><USER2> Your question is ill-posed. None of these languages are inherently terrible. Terrible languages don't appear in lists like this.

If you have a very specific problem that you need to solve, it may be that one language or another is an especially bad choice. But in general all of them work. Indeed, the four which you cite are more similar than different.

Many people would agree that C++ is a relatively poor choice of language for most "web development" projects, and yet there are many fine web-based systems built in C++. The original Amazon.com was written in C++ and it didn't exactly fail:

<http://highscalability.com/amazon-architecture>

<comment><AUTHOR> Why then do I hear/read, Ruby on Rails has problems with routing and templating, and that PHP is just as bad as C++?</comment></comment>


Project Xanadu - <AUTHOR> http://en.wikipedia.org/wiki/Project_Xanadu <comment><USER2> Back when Google Wave was all the buzz I thought that would be a great base to use to implement Project Xanadu. It didn't last long and I never even did of proof of concept. :-/

Hmmm, Wave isn't quite dead yet... <http://en.wikipedia.org/wiki/Apache_Wave></comment>