Metaphors in Man Pages - <AUTHOR> https://jvns.ca/blog/2020/05/08/metaphors-in-man-pages/ <comment><USER2> I think the author is overreaching, or rather, this is how natural language works for all fields of discourse (um, "fields", am I using a geography metaphor?)

The author mentions a talk by Maggie Appleton (which I've not heard, so maybe she's being misrepresented [1]) where she asks "Aren't metaphors just a frivolous distraction?". But it becomes impossible to talk about anything, software included, without using them. To the point where I question whether it's useful at all to think of them as metaphors.

How else talk about what a string or a file contains without using the word "contains"? Is "she had no more ideas" clearer than "she ran out of ideas"? (And wouldn't the former be a metaphor of possession, as if one could "have" ideas? Maybe it's better to say "she was idea-less"?)

How would you say "he reused this variable name" without a metaphor of resources? "He chose a variable name that was also the name of another variable"?

\----

[1] edit: I've now watched Maggie's talk, and her point is that metaphors are useful and indeed inescapable.

<comment><USER3> This reminds me of the book Metaphors We Live By, by George Lakoff and Mark Johnson ([https://press.uchicago.edu/ucp/books/book/chicago/M/bo363799...](https://press.uchicago.edu/ucp/books/book/chicago/M/bo3637992.html)). Edit: of course it's mentioned in both the article and the talk, no wonder it's so relevant :)

It discusses how metaphors in language fundamentally shape how we think and behave, even when we aren't aware of them. For example, in the second chapter they write about the concept "Time is money":

== (this is a quote, including the italics for emphasis)

 _TIME IS MONEY_

You're _wasting_ my time.

This gadget will _save_ you hours.

I don't _have_ the time to _give_ you.

How do you _spend_ your time these days?

That flat tire _cost_ me an hour.

[...more examples omitted here for brevity]

Time in our culture is a valuable commodity. It is a limited resource that we use to accomplish our goals. Because of the way that the concept of work has developed in modern Western culture, where work is typically associated with the time it takes and time is precisely quantified, it has become customary to pay people by the hour, week, or year. In our culture _TIME IS MONEY_ in many ways: telephone message units, hourly wages, hotel room rates, yearly budgets, interest on loans, and paying your debt to society by "serving time." These practices are relatively new in the history of the human race, and by no means do they exist in all cultures.

== (end quote)

Reading that passage, especially the last line, _by no means do they exist in all cultures_ , really hit me. I never really realized how common these time=money metaphors really are, and I literally can't imagine a world where time is not money myself - the metaphor is that internalized.

<comment><USER2> Very interesting! Both Julia (the article's author) and Maggie (the person she quotes) mention this book, _Metaphors We Live By_.

I've now heard Maggie's talk and she seems reasonable. It's only the article's author that seems to be stretching it too far...

</comment></comment></comment><comment><USER4> I really appreciate NDPI (Not Deep Programming Insights) like these. As programmers we seem to continually seek Grand Unified Theories in the hopes of simplifying our life or ascending to a new level of existence. It's nice to file information away for use later that doesn't have broader implications. Next time I work on a small, single use tool I'll definitely refer back to this and consider what metaphor works best for my documentation.

</comment><comment><USER5> Calling a lot of these "metaphors" is really stretching it - many of them are just homonyms with some distant shared etymology that may or may not have been metaphorical like 500 years ago.

<comment><USER6> Fwiw the word you're looking for is synonym. Homonyms have the same pronunciation but different meanings.

<comment><USER7> Homonyms is correct. "Dies" applied to a process means something completely different from "dies" applied to a person. They're two different words with the same pronunciation.

</comment></comment></comment><comment><USER8> I've always grappled with why you call something a "metaphor" if you have no other word to call it. It always seemed to me that metaphor was something you used instead of the common term for something, for poetic or rhetorical effect; if there is no common term, why does a homonym become a metaphor? For example, what is the non-metaphorical term for the legs of a chair?

<comment><USER9> It is a metaphor in the literal meaning of the word metaphor (i.e. it's a word that "carries many" meanings).

To me, _prose_ is a metaphor if it deliberately plays with the double-meaning, or uses it as an analogy to explain an example.

"I killed the process" isn't a metaphor to me.

"I killed the process, but its life wasn't too exciting anyway, it was just a spin-lock" would be a metaphor.

"The server's dropping packets": no metaphor.

"The server's dropping packets, and it's made a mess all over the client's carpeting.": metaphor, kinda pushing the utility, though.

If you go with the single-word definition, and care at all for etymology, almost everything is a metaphor. It's kind of fun to go on those adventures. Most of the words we use to describe cognition are metaphors for physical activities. "Understand", "Comprehend", "Grasp".

</comment></comment><comment><USER10> I don't understand how "backend" is a metaphor for orientation like "up", "back", "forward". It's a term that etymologically comes from "back" but has no semantic connection to the word.

<comment><USER11> Surely it's a very literal semantic connection? The backend is in back of (in the sense of behind, from the user's point of view) the frontend ….

<comment><USER12> That's still a metaphor; how processes actually occupy space isn't relevant to the distinction. If the backend is running on a laptop right in front of you, it's still a backend. The frontend is probably on the same machine, nether in front of or behind the backend "really." But we see the frontend's display, just like we see things that are in front of other things (and not things that are behind other things,) thus the metaphor.

<comment><USER11> I agree that it is a metaphor. I meant to reply to the claim that there was no semantic connection, but I agree that I chose wording that unfortunately seemed to contrast literal truth with metaphorical truth.

</comment></comment></comment></comment><comment><USER13> Woah. There's something deep about the way we describe ideas/ingenuity.

> ideas as cutting instruments: "that's an incisive idea", "that cuts right to > the heart of the matter", "he's sharp"

Ideas as fire: bright idea, that's lit, spark of inspiration, burning passion.

Sharp rock. Fire. Earliest inventions.

Also, data is food (early connection to resources):

The algo _barfs_ on ill-formatted csvs. The database is _full_.

Arguably, _pipes_ \- mode of conveyance of water, sustainer of life.

</comment><comment><USER14> Darmok and Jalad at Tanagra

</comment><comment><USER15> > "semiotics has become quite chic"

Hehe, does anyone know some good resources for semiotics self study?

<comment><USER16> I've been told that C.S. Pierce wrote some interesting stuff. A lot of the theory behind the semantic web is also relevant.

</comment></comment><comment><USER17> Light orange links on white aren't easy to read.

<comment><USER18> looks pretty good to me

<comment><USER17> Contrast ratio of 3.06:1, fails WCAG. I'd call that pretty dire.

<comment><USER18> it's pretty easy for me to read

<comment> yjftsjthsd-h And the code works on my machine, but the deploy still failed.

<comment><USER18> what do you mean

<comment> yjftsjthsd-h Sibling comment explained my point correctly, but in the interest of fleshing out my comment more nicely:

There is a meme in software development, of a developer who writes code, tests locally, and pushes, only to be told that the code fails for other devs, or on CI deployment to a testing environment, or whatever, and responding "well it works on my machine". Depending on the case and how charitable you're feeling, the dev in question can mean that as anything from "how strange that it worked here and not there; let me start debugging", to "well it worked for me so your system must be the problem".

My analogy was that you are a single person who appears to be claiming that the text style in question is totally fine because on your screen and with your eyes and brain, the text is readable. And this is not without value, but it comes across as a bit tone-deaf when others pipe up and say that it isn't readable to them, and even offer an objective standard by which the claim could be assesed, and you simply _repeat_ that it works for you. Like... we believe that you don't see a problem, but clearly other people do, and they've even offered a way to remove the subjective human evaluation and you still don't seem to believe that they might have a point.</comment></comment></comment></comment></comment></comment></comment>


What would you name a service that provides tutoring/ competition to kids? - <AUTHOR>

<comment><USER2> Try google's prizes.org

<comment><AUTHOR> thanks! love the site.</comment></comment>


Building a State of the Art Bacterial Classifier with Fast.ai and Paperspace - <AUTHOR> https://blog.paperspace.com/building-a-state-of-the-art-bacterial-classifier-with-paperspace-gradient-and-fast-ai/ <comment><USER2> This is very cool.

I've taken an interest in cytotoxins and cytotoxic therapies lately, and there seems to be a use here to help identify and measure impact of various treatments on the cell lifecycle.

One example is the following which shows the difference in cell lifecycle between untreated cancer cells and those being treated with a 200KHz electromagnetic field ('TTFields'): [https://www.youtube.com/watch?v=voVa7Pj2xUg](https://www.youtube.com/watch?v=voVa7Pj2xUg)

Presently videos like the above are manually reviewed. However, the timescales and noise of some of these observations seem to stretch human attention quite a bit. The unblinking eye of a neural network might help inform the process, if for no other reason than to help direct human attention to anomalous behavior.

For example, in the above video 'blebbing' is seen as an indicator that the cell has started apoptosis and will subsequently die. This is supported by the overall lack of growth in the culture and the mechanism of action is attributed to tubulin disruption.

However, later analysis shows that the cells actually recover from this state but tend to have corrupted mitosis in the future. This in turn indicated that the mechanism of action may be something else.

</comment><comment><AUTHOR> Hey HN, author here.

This post was the result of a small set of experiments that came out of the Paperspace Advanced Technologies Group. We've been working on some pretty ambitious research projects at the intersection of systems, ML, and HCI, and we were evaluating tools and libraries (i.e. Keras and Fast.ai) that would allow us to prototype concepts quickly. (More on our research approach and project structure coming soon). We found this interesting classification task and used it as a testbed for some small scale testing and the results were pretty cool!

<comment><USER3> Solid work - hats off!

<comment><AUTHOR> Thanks my friend, hope all is going well with you! I've been working on some cool stuff, will definitely share with you soon.

<comment><USER3> Awesome, looking forward to it!

</comment></comment></comment></comment><comment><USER4> Anyone that liked this tutorial should check this course: [https://course.fast.ai/](https://course.fast.ai/)

1) It's free 2) Jeremmy is a good teacher and one the library creators.

<comment><AUTHOR> Second this! The course is solid and drops you right in to practice, which is great.

You could actually replicate all the work in this post after just watching the first lesson, that's how fast you start learning.

</comment></comment><comment><USER5> Since 'hsikka is here in the thread - wondering if you can clear up a question that I have from your article.

In the FastAI course, they use the descending limb of the one-cycle curve to set learning rate cutoffs. So I was expecting to see your final model fit with learning rates between ~3e-4 and ~5e-2. However, you used 1e-6 and 1e-4, basically on the flat portion of the curve. That seemed to work just fine for you.

Am I correct that you didn't follow the standard recommendations for the learning rate from one-cycle, or is there some mismatch with the figure?

</comment><comment><USER6> Very cool. I'm surprised ResNet50 had so much of an advantage over ResNet34 with only 660 samples.

<comment><AUTHOR> Yes, it shocked me too! In this project I didn't get a chance to dive deep into some of the decisions the Fast.ai Library did, but I'm hoping to see if there's some inherent gain based on training.

I'm also very curious what the performance of some of the newer architectures, i.e. capsulenets would look like.

<comment><USER6> I know this is a simplistic comment, but do you suppose it was overfitting? I know the tools try to avoid this, but with so many parameters in ResNet50 maybe it's harder to avoid.

<comment><USER7> Deep neural nets have a natural tendency to overfit.

Ideally, you have a held-out test which the model hasn't seen and only used after model has trained and tuned on the dev and validation sets. Often bad experimental models will repeatedly use the test set in fine-tuning an existing model which may result in your model learning about the test set rendering the test set useless.

In the practice real world results may vary as your training and test data may not represent the actual distribution of the real world data.

</comment></comment></comment></comment><comment><USER8> Man I had such a problem using paper space's notebook system, that I just gave up.

In retrospect though it was more to do with me not understanding how to use generator functions to better control memory bloating.

<comment><USER4> Have you tried Google Collab? I tend to use it a lot for running tutorials.</comment></comment>


The $100,000 Battery That Could Help Hotels Save Bundles of Money - <AUTHOR> http://www.theatlantic.com/technology/archive/2013/11/the-100-000-battery-that-could-help-hotels-save-bundles-of-money/281194/ <comment><USER2> >That's a double-edged sword for utilities, depriving them of demand charges that help finance improvements to the transmission system but also helping them keep balance the grid and avoid blackouts or having to fire up a carbon- spewing fossil fuel power plant when demand suddenly spikes.

I'd like to see a quote or statistic that says that this is true and that the utilities are really price-gouging customers for peak demand charges. It would not surprise me at all to learn that the added cost to utilities of handling peak demand was more than the surcharge they are recouping from businesses - in which case they would be happy for everyone to install load-balancing units in their buildings.

This is supported by the article itself, in saying that the utilities are rewarding customers for using less electricity during peak times (by controlling their air conditioners).

<comment><USER3> If that were true, wouldn't the utilities just buy the batteries themselves?

<comment><USER4> Not if they can just charge the customer extra. Where's their incentive?

<comment><USER3> Charging the customer extra when there's not enough supply is inefficient and leaves money on the table. They just end up selling less electricity. In fact, they're depending on it to stop their grid from crashing. In general, raising prices in response to demand spikes is always worse than just increasing supply to meet it (assuming you can) because of demand elasticity. Having the customers all buy batteries fixes that, but in practice I don't see how it can be very efficient to have your customers tackle your supply problem one-by- one. It would make more sense to just charge some sort of premium to exempt them from high-demand-time surcharges. Would cover the battery cost and prevent the market distortion.

Look at it from the top down: would electrical companies rather be able to meet the full demand for electricity or not? Clearly, they would. Otherwise, _why make electricity at all?_

I'm not an economist, so I'd be happy for someone to take that apart. One objection is that this charge-more scheme allows the power company to price discriminate against customers who are less price sensitive (like hotels, who just _need_ AC), but...well, I need to be convinced.

</comment></comment></comment></comment><comment><USER5> I think this is regulatory lag. Most peak power is provided by NatGas these day, and NatGas is cheap. If Lithium-ion made sense at the wholesale level, then power companies would do it. I'd bet this is because some regulatory commission decided on rates for peak/non-peak based on information that is no longer relevant.

<comment><USER6> Commissions don't decide peak power prices, the marginal producers of power do. And, yes, natural gas is a large portion of the power stack, but peak days (which only happen a nominal number of times per year) are driven by plants that come online for short periods of time at high marginal costs.

Power companies just pass through market rates, they are mostly ambivalent to driving down rates as they just tax tolls on each transaction.

<comment><USER7> Not sure where you're describing, but it varies by jurisdiction. In California, a commission called the California Public Utilities Commission (CPUC) sets electricity prices charged by all the major operators. See for example:

[http://www.cpuc.ca.gov/PUC/energy/Electric+Rates/](http://www.cpuc.ca.gov/PUC/energy/Electric+Rates/)

Of course this is subject to a long-term constraint that rates must be sufficient to support generation and wholesale purchase... but there's no direct "pass through of market rates" on an hourly, daily, or monthly basis.

</comment></comment></comment><comment><USER8> It sounds like they are trying to game the system by lowering their Peak Load Contribution (PLC.) Good article explaining Capacity charges in PJM [http://energysmart.enernoc.com/bid/188545/Deconstructing- You...](http://energysmart.enernoc.com/bid/188545/Deconstructing-Your-Energy- Bill-Capacity-Charges) They only have to use these batteries for a few hours a year to save money all year round.

But, the capacity charge for PJM for 6/1/2013 - 5/31/2014 is $27.73 MW / day. So if you can drop your PLC by 54kW, you would save $27.73 * 0.054 * 30 = $44.91 a month. Hardly enough to make the $100k 54 kW system worth it.

Disclaimer: I know enough about the energy markets to be dangerous. I mostly know about PJM, so YMMV in CAISO.

<comment><USER9> Interesting!

Looking at what I think is the right PG&E tariff for them [1], I can't quite figure out what it means. However, I found a helpful guide [2] that includes an actual hotel electrical bill.

Reading that, their summer difference is $0.07/kWh, so the box only could save them $3.50 a day on cheaper energy. There they are paying $13/kW for peak capacity, $8.58 for off-peak, and $2.99 for "partial peak", whatever that is.

So it sounds like being able to level peaks in your power consumption could be a big win. Even if you level it within peak, therefore saving nothing on a kWh basis, a little curve smoothing could pay big dividends.

The interesting question for me is how much this is incentive gaming versus solving a real problem for generators.

[1] [http://www.pge.com/tariffs/tm2/pdf/ELEC_SCHEDS_A-10.pdf](http://www.pge.com/tariffs/tm2/pdf/ELEC_SCHEDS_A-10.pdf) [2] [https://sites.google.com/site/greenwrenco/san-francisco- bay-...](https://sites.google.com/site/greenwrenco/san-francisco-bay-area- resources/understanding-demand-charges-on-your-business-pge-bill)

</comment></comment><comment><USER10> Strange. I would honestly have thought that the losses involved in storing energy in a battery (I would expect at least 20% loss) would have out-shadowed the savings by avoiding extra charges for high demand. It's surprising to me that batteries were chosen as the energy storage method and also that the energy provider themselves is not doing this on a large scale if it's a big issue to them. A very interesting read.

<comment><USER11> Also, there would be a loss when converting the batteries' DC back to AC to drive the hotel's air conditioning and other systems. And doesn't charging a battery generate heat, which you would need additional air conditioning to remove on a hot day?

I wonder whether it would be environmentally sustainable if every home or business in the world started using batteries for power storage and electric vehicles. For example, how much environmental damage would be incurred from mining lithium on a massive scale? Are there even enough known lithium deposits in the world to make this practical on a large scale?

<comment><USER12> You can mine lithium out of the ocean cost-effectively. By the time is becomes scarce, we will have moved on to a new technology.

</comment></comment></comment><comment><USER13> Flywheels would be a great solution here: [http://en.wikipedia.org/wiki/Flywheel_energy_storage#Compari...](http://en.wikipedia.org/wiki/Flywheel_energy_storage#Comparison_to_batteries)

Someday they might be commercially viable....

<comment><USER14> Exactly what I was thinking about reading the article: you've got a huge, fixed energy storage system to set up, why not use a flywheel? That's pretty much a best-case situation for them even if you don't need the transient load ability of a flywheel.

<comment><USER15> Or even (it _is_ a hotel) pump water to tanks on the roof, making a small pumped storage hydroelectric system.

Would love someone to do the comparisons of cost and energy density of all 3 solutions.

<comment><USER14> Pumped hydro scales awesomely and is relatively low maintenance, but it has a fairly low energy density, wikipedia quotes 272Wh for 1m^3 at 100m (~30 floors). That's 0.272Wh/kg. You either need tremendous amounts of water, significant height, or both.

By comparison, your ultra-basic low-energy-density lead-acid battery pack is 30~40Wh/kg, 100 times the energy density, and a Li-ion is 130~200Wh/kg.

<comment><USER16> It's fun to throw out numbers for pumped storage. The Ludington pumped storage plant [1] is pretty big at 1.8 gigawatts. At full power, that's 33 million gallons per minute. The reservoir is 27 billion gallons of water (about 100 billion liters).

[1] [http://en.wikipedia.org/wiki/Ludington_Pumped_Storage_Power_...](http://en.wikipedia.org/wiki/Ludington_Pumped_Storage_Power_Plant)

</comment></comment></comment></comment></comment><comment><USER9> Does anybody get why they're going with lithium ion batteries over lead acid?

Looking at a comparison [1], the cost and lifetime look substantially better. And the technology has been proven out over decades by, e.g., telcos. I'm not getting why they'd use fancy laptop-style batteries when weight isn't an issue.

[1] [http://www.altenergymag.com/emagazine/2012/04/a-comparison-o...](http://www.altenergymag.com/emagazine/2012/04/a-comparison- of-lead-acid-to-lithium-ion-in-stationary-storage-applications/1884)

<comment><USER17> Just looking at table 2 from the article you link, it looks like lithium ion has the following advantages over lead acid for this application:

* Greater energy density, which means you need to carve less space out of your existing floor plan to make room for batteries.

* About twice the cycle life, so batteries need replacement less often.

* Can discharge more deeply without harming cycle life, so for applications where discharging happens frequently that means either the effective energy density or the effective cycle life is even greater.

* Better efficiency for <24h charge-discharge cycles.

These are all things that are more advantageous in this kind of application, where you can expect to see a lot of repeated cycling during hot summer months. For a telco application, where you're presumably only expecting infrequent use during occasional power outages, they'd be of negligible value.

Keep on reading to figures 5 and 6, where they look in more detail at cycle life, and the lead acid batteries start to look like a straight-up bad choice for this kind of application.

<comment><USER9> Oops, I read the first table wrong. You're exactly correct on the deep discharge stuff. Thanks!

</comment></comment></comment><comment><USER18> It's very interesting to see rumors circulating that public utilities are worried about solar energy adoption cutting into their business.

Is this actually true? Is the total cost of ownership becoming sufficiently low as to drive adoption?

<comment><USER19> Yes. Even without subsidies, a grid-tied solar power system will pay for itself well within the lifespan of the cells (the lifespan of solar panels is 25-50 years). A battery-backed "off the grid" system is not there yet, because the batteries are expensive. How soon it pays off will depend on how cheaply you obtain the panels and how much you pay for installation; these vary _wildly_ depending on the location and vendor.

I did my own solar installation for about $1000, and it's enough for me to live lightly on (no AC, no microwave, no electric heater, but laptop and phone and hotspot stay charged, and fans can run indefinitely). Fridge runs on propane, when I'm off-the-grid. I'd need to quadruple that to turn on the AC or electric heat for any length of time, and would need a lot more batteries (I have three group 27 deep cycle batteries and a 3000 watt inverter).

Anyway, I got sidetracked a bit. We're currently at the point where a DIY installation can pay for itself in under 9 years. Maybe even as little as 7. Professionally installed systems, with subsidies, are probably around the 10 year repayment mark. And, the panels get cheaper every time I look into it. The batteries stay pricey, though.

<comment><USER20> I'm also off the grid, and fortunately it's sunny now so I can write this message :)

Can you please explain what kind of batteries are you using?And what are your usage patterns? For example I'm using two 12V 200A lead batteries, I'm trying to use then only on 30% discharge so that they will last longer.

<comment><USER19> I have three Interstate group 27 deep cycle marine lead acid batteries. They are rated for 65 amp hours (more at lower amperage draws...which is why having more batteries is helpful); which is enough to where I _almost_ never have to run my generator, unless it rains for a couple of days.

They're nothing special, just heavy as hell lead acid batteries. I also try to never discharge too low...my rule of thumb is 50%, though I've run them until the inverter shut off due to low power. So, I've obviously gone below 50% a few times. They're three years old, and starting to show signs of degradation. I bought them at Costco for, I think, $98 each, and I'm pleased with the return on investment, given that they've gotten me out of being stranded on more than one occasion (I'm in a motorhome, and the chassis battery has been an interesting component, having more than it's fair share of failures, always in very bad places to have a motorhome that won't start).

I should point out that when I am off-the-grid, I am extremely _conscious_ of my power usage. I charge _everything_ during the day, religiously, so that I don't even have to turn the inverter on, some nights (lights, fans, water pump, and fridge igniter are 12V). It's a ritual...actually, it's a really satisfying ritual that I miss when I'm living plugged in. I need to go get lost in the desert or in Mexico this winter; been parked too long.

</comment></comment></comment></comment><comment><USER21> Come on, journalists. What is a 54 kW battery pack? Is that the peak power it can provide? What about the far more interesting capacity?

It is like failing to mention the range of a car but insisting it can produce plenty of torque.

<comment><USER22> I await the day when a single article is published with a proper unit of power or energy. If it's not a 54 kW battery it's a windmill that generates 3 MW per year.

</comment></comment><comment><USER23> Odd that it costs more than a Tesla but holds less energy.

</comment><comment><USER24> Or you could have a fleet of electric cars for the business that plug back in and charge up in time to run the electric load during peak demand.

</comment><comment><USER25> As well as recharging these things with solar, hotels could hook their gym treadmills into the system and turn their guests into power-generating hamsters: [http://www.californiafitness.com/sg/en/node/587](http://www.californiafitness.com/sg/en/node/587)

</comment><comment><USER26> Imagine charging these at night, and selling back to the grid at peak demand. Granted, it'd probably kill these things very quickly.

</comment><comment><USER20> Now in Europe, there are solar batteries for less than 1Eu/Watt, on E-Bay for less than $1.6/Watt, you can buy for these money more than 60kWatt of solar panels, but with bulk prices you could buy even more, and all this energy will be available during peak hours during day, to power condition systems.

</comment><comment><USER27> This is a symptom of degraded infrastructure and dysfunctional energy policies. It is not a smart move considering total resource efficiency.

It's like how you see lots of individual bypass solutions in countries with bad infrastructure.

</comment><comment><USER28> Whats the shelf life on these?</comment>


Show HN: Push Out Fans – a casual puzzle game based on a very simple mechanism - <AUTHOR> http://www.tapirgames.com/Games/PushOutFans

<comment><USER2> Very nice work! One suggestion for a small feature - it would be nice if the screen where you select a level showed your best (lowest) number of moves for levels you have beaten, and once you have beaten all levels, showed the total moves for all levels.

The point of this is that I could then send this to my brother/coworker/arch- nemesis and challenge them to beat my score (as with the old Flash game "Magic Pen", for example).

<comment><AUTHOR> good advices! This game has a sister game, which will be released soon. I will improve it as you said. Thanks!

</comment></comment><comment><USER3> This requires Flash. Is there any chance of a html version?

<comment><AUTHOR> Yes, it will be ported to html. But this would need much time to finish.

There are mobile versions for this game, so you can try it on your phone: [http://www.tapirgames.com/App/Rectangle- Pushers](http://www.tapirgames.com/App/Rectangle-Pushers)

</comment></comment><comment><USER4> Thanks for such a fun game!

<comment><AUTHOR> glad you like it!

</comment></comment><comment><USER5> interesting, what framework was this built with? unity?

<comment><AUTHOR> It is built with Phyard Builder, which is written with ActonScript3. However, the editor is planed to be ported to c++ with html release target supported.</comment></comment>


What Is Electricity? (2013) - <AUTHOR> https://learn.sparkfun.com/tutorials/what-is-electricity/ <comment><USER2> I teach high school physics. Here's my notes/textbook on electricity with simulations and equations rendered in LaTex.

[https://landgreen.github.io/physics/notes/circuits/electrici...](https://landgreen.github.io/physics/notes/circuits/electricity/index.html)

<comment><USER3> Awesome notes. I haven't had my coffee yet so perhaps I'm just misreading this part:

"In 1746 Benjamin Franklin mistakenly assigned a negative value to the charge carriers that we now call electrons."

Shouldn't that read "mistakenly assigned a _positive_ value to the charge carriers that we now call electrons"?

<comment><USER2> Nope! It's kinda silly. We all call electrons negative because of how they were labeled 250 years ago. If he had labeled them positive the math involving electric current would be a bit easier.

[https://xkcd.com/567/](https://xkcd.com/567/)

<comment><USER4> I've been hearing for years that the math involved would be easier if we switched signs on the electron but what equation specifically would be simpler? One would still have to deal with both polarities. I tutored electrical engineers for years and the biggest misconception by far was always considering the amount (or movement) of charge and the number of particles to be equivalent. Polarity was never really an issue.

<comment><USER2> A couple things off the top of my head from teaching high school physics:

It would make the direction of current the same as the flow of charge.

It would make electric fields predict the force on electrons.

It would make the right-hand rule for magnetic fields work for electrons and instead of the left-hand rule.

<comment><USER4> But existing theory predicts all those just fine, it just happens that some things are not in the same direction, but it's not like one can ignore direction. The math is still always there. And I argue things going in different directions is a feature, not a bug, because it reinforces the point that net charge and net particles are not the same thing.

<comment><USER5> Right, the math is the same. We face this in physics all the time. You drop a ball and it accelerates downward. Should the distance it covers be a negative number? Well, it seems linear distance should be positive, but if it is, then does down become positive? Shouldn't up be positive? Or do we reverse from end-minus-start and make it start-minus-end?

It doesn't matter. The math is all the same with just different labeling conventions.

For the general physics of electric charges, the convention that a proton is +1 and electron is -1 is somewhat useful as a reminder of the larger range of phenomena: protons carry charge, too, and a movement of positively charged molecules makes the charge carriers and current move in the same direction.

But as soon as you start working with practical, artificial electrical circuits (as opposed to, say, neurons), the electron-is-negative is a nuisance, because the charge carriers are almost always simple electrons. To visualize "stuff" moving one way, you have to visualize "other stuff" moving the opposite direction. You have to keep thinking that when you add more you get less. Visualization of electric/electronic technology would have been a lot more convenient if the convention had been that electrons were positive, protons negative.

<comment><USER4> We're probably going to have to agree to disagree on this one as I just don't see the nuisance and I see some positive aspects to the existing convention which I highlighted previously.

The classic, and really intuitive, experiment that requires one to understand the movement of both the carriers and the charge at the same time is the Haynes Shockley experiment [1]. It has not been my experience that charge convention gets in the way of students interpreting this experiment.

For the vast majority of practical (artificial?) electronics, when designing one only needs to look at the movement of net charge. Passive sign convention (used by spice) is about the flow of charge, not carriers. Maxwell's equations don't even mention the carriers. It's not clear to me why one needs to visualise carriers to design circuits. In my experience (i.e. transmission lines) it can actually hinder students to consider the movement of carriers when designing a practical circuit.

[1] [https://en.wikipedia.org/wiki/Haynes–Shockley_experiment](https://en.wikipedia.org/wiki/Haynes–Shockley_experiment) [2] [https://en.wikipedia.org/wiki/Passive_sign_convention](https://en.wikipedia.org/wiki/Passive_sign_convention)

<comment><USER5> artificial: "made or produced by human beings rather than occurring naturally"

</comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER6> One aspect of electricity I think is useful to emphasize is that electrons in a conductor move more like the steel balls Newton's cradle (that toy you may have seen where a ball strikes one end of a line of balls, and nothing moves except the end ball, or you can pull back two balls and then only two balls will move, and so on). This can help with intuition about the distinction between "holes" and electrons, and how energy can flow with holes (which is quite counter-intuitive, I think). In terms of mental model, the _ratio_ of holes to ambient electrons is sometimes useful to think about, as this is fundamental to computing current limits of conductors.

There is a diagram (an animated GIF) about half-way down that sort of implies the newton's cradle method of moving charge, but I don't like it because it's not clear enough. Also, I see current as more of a fixed cloud of valence electrons with holes moving through it - which is a very different intuition than what this diagram implies.

<comment><USER2> Here's my take on a cartoony conductivity simulation. I've got three models: conductors, semiconductors, and semiconductors but with holes.

[https://landgreen.github.io/physics/notes/electromagnetism/c...](https://landgreen.github.io/physics/notes/electromagnetism/charge/index.html#conductivity)

<comment><USER7> I like these diagrams. Now I want to see what superconductivity looks like in your framework. An unimpeded stream of electrons flowing as if the red dots aren't even there?

<comment><USER2> My simulation just runs classical physics (Coulomb's law + Newton's laws). It's missing any mechanism for super conductivity. Although, I could just turn off friction.

I think superconductivity means the electrons pair up and stop colliding through the Pauli exclusion principle. I didn't code any collisions, so maybe it's already modeling a crappy version of superconductivity!

</comment></comment></comment></comment><comment><USER8> Just amazing! Imagine all the physics and knowledge from multiple sciences, disciplines and fields are used when someone tells Amazon Echo to turn on a charger or socket that's connected to a phone or laptop.

Echo -> ISP wires —> Undersea Cables —> Amazon Servers -> Back home -> Electricity flow

And this is so super high level

All of these devices on the way are powered by electricity from dams, solar, wind etc. Before voice to speech hits or data is read. Processors and hard disks must do so much heavy lifting

It's surreal the level of abstraction we are surrounded by..

<comment><USER9> Quite fascinating and mind-boggling. What really blows my mind is that technology is still extraordinarily less complicated than (bi|ec)ology.

</comment></comment><comment><USER10> A thread from 2015: [https://news.ycombinator.com/item?id=10400123](https://news.ycombinator.com/item?id=10400123)

</comment><comment><USER11> It's interesting to me when I read it. We take it down to the proton neutron and electron stating they are charged with positive negative or neutral charge.... but what are they charged with ?

Electricity ? What is it made of ?

<comment><USER7> It's made of the electromagnetic force. We can measure it and characterize it very accurately with mathematics. We can say what it _isn 't_ (gravity or the weak force or the strong force), but we cannot say what the electromagnetic force _is_. Sorry. If you figure it out you'll get a Nobel Prize.

<comment><USER12> > We can say what it isn't (gravity or the weak force or the strong force)

Isn't the electric and the weak force considered the same force these days? See also [https://en.m.wikipedia.org/wiki/Electroweak_interaction](https://en.m.wikipedia.org/wiki/Electroweak_interaction)

</comment></comment></comment><comment><USER13> For an exercise in clear (and perhaps provocative) thinking, try:

'What Is "Electricity"?' ©1996 William J. Beaty

> What is electricity? This question is impossible to answer because the word > "Electricity" has several contradictory meanings. These different meanings > are incompatible, and the contradictions confuse everyone. If you don't > understand electricity, you're not alone. Even teachers, engineers, and > scientists have a hard time grasping the concept.

> Obviously "electricity" cannot be several different things at the same time. > Unfortunately we've defined the word Electricity in a crazy way. Because the > word lacks one distinct meaning, we can never pin down the nature of > electricity. In the end we're forced to declare that there's no such stuff > as "electricity" at all!

[http://amasci.com/miscon/whatis.html](http://amasci.com/miscon/whatis.html)

<comment><USER14> Analyzing the meaning of words is characteristic to philosophy and is not a sign of "clear thinking."

</comment></comment><comment><USER15> This is trivial for somebody who studies electrical engineering in highschool

<comment><USER16> Basic introductions of a topic are trivial for people that are studying that topic? Shocking!</comment></comment>


LHC sees first record-breaking high-energy particle collisions - <AUTHOR> http://news.bbc.co.uk/1/hi/sci/tech/8593780.stm

<comment><USER2> The awesome thing about the LHC is that they expose loads of its operational details live on the web, so you can see what's happening right now in confusingly large amounts of detail.

"Page 1", which is the main accelerator status screen: [http://op- webtools.web.cern.ch/op-webtools/vistar/vistars.ph...](http://op- webtools.web.cern.ch/op-webtools/vistar/vistars.php?usr=LHC1)

Operational status of the experiments: [http://op-webtools.web.cern.ch/op- webtools/vistar/vistars.ph...](http://op-webtools.web.cern.ch/op- webtools/vistar/vistars.php?usr=LHC3)

Cycling status screens for the CMS experiment: <http://cmsdoc.cern.ch/cmscc/cmstv/cmstv.jsp?channel=4>

Status for the LHCb detector: <http://frankm.web.cern.ch/frankm/test/Online/Stomp/web>

You can also find loads more links at <http://lhcportal.com>

</comment><comment><USER3> > This marks the beginning of work that could lead to the discovery of > fundamental new physics... Many of them have described Tuesday's event as > the beginning of a "new era in science".

We don't often hear things like that in hard sciences like physics. For thousands of years, humans have been "discovering" nature and trying to piece together a puzzle.

> "If you want to discover new particles, you have to produce them; and these > new particles are massive..."

We're no longer sitting by idly, waiting to find the next piece so we can fit it somewhere. Humans are making the next piece, whatever it may be. Not to use the oft abused phrase lightly, I think this is a paradigm shift in our study of sciences where we've taken serendipity out of the equation and replaced it with engineering. LHC isn't a science project. It is the industrialization of discovery, for at the scale they are operating, it has to be.

Personally, I highly doubt we'll find Higgs anytime soon or ever. However, I'm pretty certain LHC will push the limits of our knowledge further.

<comment><USER4> Not to downplay the LHC, but scientists and physicists have been creating the material ("making the next piece") for fundamental new physics for a while now. The quantum hall effect, Bose-Einstein condensates, nuclear explosions, etc...

LHC certainly is a big step in particle physics, but I'd be hesitant to label it a paradigm shift. Nature is nature; it's there and waiting to be figured out... but sometimes it doesn't naturally create what it's capable of creating.

<comment><USER5> To be pedantic regarding your last sentence, these sorts of collisions do happen in nature. It's just that they're pretty much impossible to observe given that we have to look really, really close and they're so spread out.

</comment></comment></comment><comment><USER6> A historic tweet:

Experiments are collecting their first physics data - historic moment here! Watch the webcast, look at the photos - all live! <http://twitter.com/CERN>

<comment><USER3> Direct link to the webcast: <http://webcast.cern.ch/lhcfirstphysics/>

<comment><USER7> webcams inside the collider itself <http://www.cyriak.co.uk/lhc/lhc- webcams.html>

<comment><USER8> Very good.

<comment> Tuna-Fish My first thought was: "That's not what it would look like."

I'm too much of a geek.

<comment><USER9> Or not enough of one...

<comment> Tuna-Fish Please elaborate. What I meant was that if they did make a black hole, and it for some reason would stay on earth (instead of being flung out of the solar system at an appreciable fraction of the speed of light), all the matter on earth would form a black hole with a Schwarzschild radius of less than 1 cm.

Thus, a black hole created at rest at CERN devouring the earth would never be seen -- it would just fall down and let the pressure of earth push matter into it. Done properly, the webcam feed should show a pretty major earthquake that just keeps getting worse.

<comment><USER10> Wrong. Any black hole produced at CERN Would evaporate instantly. <http://en.wikipedia.org/wiki/Micro_black_hole> If it were possible to create an earth eating black hole, cosmic rays would have done the job long ago. They are way more powerful than the LHC.

<comment> Tuna-Fish I am aware of Hawking radiation, but it does not properly explain how a black hole would evaporate after reaching Planck mass, only that it would reduce in mass until it was unable to attract anything. (There is a very reasonable proposal that black holes thus reduced would actually be stable weakly interacting massive particles, and would form much, if not all, of dark matter.) Also, if a black hole would be created at CERN, it would be fed by a very energetic proton beam, potentially much faster than it could possibly evaporate by hawking radiation.

That cosmic rays also potentially produce black holes is also not a good argument against their production, but only against the danger they pose. A black hole with the mass of a few grams has a very tiny cross-section, and since momentum is conserved, would probably be moving very close to the speed of light. Should a cosmic ray hit earth and produce one, it would likely pass right trough earth without hitting any significant amount of matter or slowing down. This is of course also true for any black hole created at CERN -- The protons traversing the rings are doing so at roughly 0.99999999c. Should a black hole be created, it would leave the solar system in a rather short time, at least from it's perspective.

</comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER11> This is cool. 15 years ago I did my Master's thesis at ATLAS, but that's the last I had to do with particle physics. I'm glad I didn't wait around for data to actually show up... (Back in 1995, 2004 was the planned start date.)

</comment><comment><USER12> I'm wondering what kind of computation engine and database they use to process and store the torrents of data. I bet its a no-no-no-SQL

<comment><USER13> There've been a few articles on that topic over time, though I don't have any links handy. Databases don't even enter the basic processing infrastructure, as they're dealing with on the order of terabytes of new data per second! I thing they even had to connect their cluster together with fiberoptics just to be able to handle all the data traffic!

<comment><USER14> Typically a cluster is connected with fiberoptics or similar media anyways. That they are doing the same is not surprising.

</comment></comment></comment><comment><USER15> Dear LHC, usher in a "new era" in collaboration too -- open source all collected data.

<comment><USER16> Are you ready to process 15 petabytes of data that LHC is expected to produce annually?

<http://public.web.cern.ch/public/en/LHC/Computing-en.html>

<comment><USER15> I personally am not, but if someone else CAN then I don't think they should be stopped. I also don't think that's a good reason to not open source data.

It would be especially hot if this was one of those free datasets on AWS.</comment></comment></comment>


Show HN: New and Easy way to discover beautiful Places to travel - <AUTHOR> https://wanderhunt.com/ <comment><AUTHOR> Know the places where your friends have been to and are planning to travel. You can discover beautiful places easily with auto suggested nearby accommodations of that place. Hassle Free way in planning your next trip. Please let me know what you guys think of this.

<comment><USER2> It's unfortunate that your submission didn't get any attention. You can iterate on the project and post it again to HN. Hopefully it gets more attention next time. Read on about when is the best time to post to HN.

As for the website itself, I think it's pretty nice, well done! Suggestion: use HTML5 geolocation API to suggest interesting places around the visitor.

<comment><AUTHOR> Hi Toni. Thank you so much for your suggestion :) i will work on that along with more features i want to add to the site. I hope more people will be attracted in the next iteration and I will post it here again in HN :)</comment></comment></comment>


The World That Twitter Made - <AUTHOR> https://scholars-stage.blogspot.com/2020/07/the-world-that-twitter-made.html <comment> just-ok This is a great post, expressing thoughts that have been brewing in my mind much better than I could. I couldn't agree more with the fundamental thesis that 280 characters cannot lead to meaningful discourse as your exposure to different communities grows. In their own words,

> _To run a high-follower account on twitter is to be constantly exposed to > entire communities whose members will treat you as an enemy to be defeated > or a buffoon to be humiliated the minute they become aware of you._

To me, though, this post begs the question: if having a large number of followers is so toxic, why do it? This post clearly misses the tight-knit blog communities of yesterday, yet they still insist on maintaining a public, high- follower profile.

If you are writing something worth reading, and only (mostly) care to interact with people who also write things worth reading, it doesn't seem prudent to open yourself up to the Internet at large. Private profiles can't be retweeted, and you get to moderate your reader list. Obviously, you reach a smaller audience, but if you are interested in "open and honest exchanges," finding people that are "intellectually interested," and getting away from the "bare-knuckle brawl," then isn't that a far, _far_ better way to reach that goal?

> _Never argue with an idiot. They will drag you down to their level and beat > you with experience._

<comment><USER2> I was going to cite that exact first quote because it reflects my recent experience on Twitter. Yesterday I deactivated my account. Did I have a large following? I think I had 1 follower, I used it to follow mostly artists and programmers.

So why did I deactivate my account? A couple of weeks ago I started following the debate around free speech because classical liberal values are close to my heart and it was like walking in on a car crash happening in slow motion. I just couldn't take my eyes of it.

In an attempt to regain my sanity and creative thinking I'm going back to reading books and having private conversations with people, preferably in- person.

Edit: HN discussions it should be mentioned are still a bastion of thoughtful conversation which I would like to maintain. In respect to that please don't make this thread political, my reference to liberal values was only to give an example of a topic largely infected with a negative discussion climate. Original article was more about the dynamics of conversation, not the topics themselves.

<comment><USER3> not that it's much use to you now, but you don't need a twitter account to keep up with someone... just use something like nitter that will let you add them to your rss reader

</comment></comment></comment><comment> rvp-x It's true that simply having 30,000 people with a quick reply button creates negative interactions, Twitter is also a website that makes money from advertising, and people watch more ads if they're "engaged". This incentivizes the website to show your content to people who will disagree with it.

</comment><comment><USER4> An issue with closed systems like youtube/reddit/facebook/HN etc. is that when you read something that you don't agree with the only way to directly have an effect (whether you actually do or not) is by joining the system and further perpetuating what it entails. Yes you can affect it from the outside by writing articles/blogposts and hope that they get enough visibility to be shown in those areas but that takes much more effort (not a bad thing).

</comment><comment><USER5> I think that world was already there. Twitter just made it apparent.

<comment><USER6> Not at all. Twitter gave everyone access to bigger microphones, and one of the main benefits of this went to asshats who would have ordinarily been booed off the stage.

The fact that these people exist isn't new. They're ability to do what they do at scale and to such a large audience is.

<comment><USER7> The instant nature and character limit of Twitter is what made it so toxic, I think. So now anyone can broadcast any dumb thought they have. If you were a blogger, you'd think about your thought more before sitting down and writing a long-ish essay about it (maybe you even learn as you write that your thought is wrong, incendieary, etc), but with Twitter...

In theory Facebook also offers this instant thing, but the idea with Facebook was, it would be limited to your friends/network...

<comment><USER6> Agreed. Those little bits of friction, whether it's needing to put the time into a blog and build an audience for it, or having some natural limits on reach, really matter.

</comment></comment></comment></comment><comment><USER8> At some point politics got intertwined with social media. Until that point ... social media was a pleasant place. I'm pretty sure had email been still active ... you would get a ton of political mails as fwds as opposed to spam.

The shit show that politics is ... is pathetic in all media irrespective of character length. Have you seen TV ? What excuses do they have, illiteracy ? The boomer crowd is dishonest. Heck anyone remember Ron Paul, who was a republican ? Maybe there should be an age limit of 40 in politics.

Surprisingly in YouTube, in some debate talks you find civility. People seem to miss out one thing, no other generation has been that active in politics for about 40 years. So that's actually a good thing as opposed to the passive acceptance you see in the older crowd.

What I think is sad is ... all this political energy going nowhere and except pointless shows of symbolism, which is fine in most cases but the lack of change is what makes the thing even worse.

<comment><USER9> We have a far too narrow view of what constitutes social media.

Every medium is a social one if you think about it and every social medium is political.

The medium has and always will be the message and when you get to the core you understand the message is simply the audience.

Do you think "primitive" civilizations compared to ours didn't have social media before the advent of the tweet?

They were operating on levels we haven't even begun to understand in our foolish pride.

We're as primitive as we were at the invention of electric light and our technological advancements have outpaced our morality. We're just amplifying the hysteria and confusion with our automated algorithms and always-on engagement and now every poor schmuck has a voice where once it was limited to the elites. You should be grateful that Twitter has democratized the inane blatherings of the proletariat to drown out the voices of so called authority.

<comment><USER8> Not all purpose of communication is political.

1\. Information dissemination

2\. Coordination

3\. Persuasion

4\. Feedback gathering

5\. Social grooming (jokes, status updates, needs ...)

6\. Artistic self-expression

All these are fairly reasonable in any social media.

Conflicting communication via threads is where they fail. Trolling is as old as threads.

<comment><USER9> Social and political are synonyms my dude but yes not all communication is political but all communication is social.</comment></comment></comment></comment>


How to write your first multi-user VR experience (on the web) - <AUTHOR> https://github.com/haydenjameslee/networked-aframe/blob/master/docs/Tutorial:%20Create%20your%20first%20Networked-Aframe%20experience.md <comment><AUTHOR> Author of the article and of the Networked-Aframe library here. Would love to hear about any issues you run into and happy to help solve any problems.</comment>


Build a Twilio Hard Phone with SIP from Twilio, Raspberry Pi, and Asterisk - <AUTHOR> http://www.twilio.com/blog/2013/03/build-a-twilio-hard-phone-with-sip-from-twilio-raspberry-pi-asterisk-freepbx-and-the-obihai-obi100.html

<comment><USER2> So many moving parts and cables. Raspberry Pi, an old phone, FreePBX, Asterisk, Obi100. Let's outcomplex the POTS.

Seriously, how about you show us how to register an Android phone with your SIP service?

<comment><USER3> Don't think Twilio has SIP registration, but they do have Android SDK for Twilio Client that will do the trick.

<comment><USER4> Yeah, this would definitely be the way to go for an Android device. Use the SDK examples to build a little dialer and use the ACTION_CALL intent, and it works great for outbound as well.

Docs and download are here - <http://www.twilio.com/docs/client/android>

<comment><USER5> Rob, are you guys looking to do SIP Reggie soon? I imagine it's gotta be coming at some point (I don't know why you guys don't do it now except for the obvious pain point of network overhead from all that registration traffic).

<comment><USER4> We're pretty stoked on what we have planned for our SIP roadmap, but staying true to our discipline of announcing features only when they ship.

SIP From Twilio is all we have to report right now.

</comment></comment></comment></comment></comment><comment><USER6> Why is Asterisk in the mix? If you call a SIP URI directly from Twilio, can't you land it directly on the ATA?

<comment><USER7> Voicemail, 7-digit dial (most SIP providers only take 10), forwarding, filtering, etc.

Twilio could theoretically handle these things for you, but they're typically handled in a PBX.

<comment><USER6> Hm, maybe I should have been more specific. Given that this is an interesting hack to get a PSTN call to an analogue set through Twilio, why did they bother with the SIP proxy?

<comment><USER7> I'm not sure I understand your question, but I think it's because the ATA (like most modern/cheap ATAs) only speaks SIP.

</comment></comment></comment></comment><comment><USER8> Now to figure out how to make this work with a rotary phone...

<comment><USER4> That would be hilarious.

<comment><USER6> Wouldn't it just work? The FXS port will generate the 90VAC/20Hz signal and the device plugged into it interprets that as an incoming call.

You guys only support termination through SIP, not origination, so the dialling mechanism doesn't matter. And if you did want to do origination, the ATA just has to understand pulse dialling.

<comment><USER4> Yeah - I think it would. Going to eBay a fierce looking red one from the sixties and going to give it a spin.

<comment><USER9> Keep it under a glass cake cover by a bust of William Shakespeare. Next up: installing firepoles DIY.

</comment></comment></comment></comment></comment><comment><USER10> awesome! I love seeing Twilio devs using "old" landline tech with the API. Way to go!

<comment><AUTHOR> Thanks! It was so satisfying to make a physical phone ring!

<comment><USER5> Not to be pedantic, but what does Twilio help here? Aren't you kind of just Jerryrigging Twilio onto an Asterisk install?

Not that this isn't cool, I just don't understand what benefit you get from having Twilio connected here. It seems like if you want to make a physical phone ring you could take a time machine back to 2004 and achieve the same thing using Asterisk, no?

Can you explain the benefit of integrating with Twilio instead of using just plain ol' Asterisk?

Disclaimer: I work at 2600hz, the open-source cloud telecom company.

<comment><USER4> Great question Josh. Big benefit here is being able to keep your voice application logic in your own code instead of in Asterisk. Often we find in business telephony applications, the really important information you want to get to and from the user isn't in the phone server, but in the CRM app or help desk app or support app that the phone server is trying to get to and from the user. The closer data like account numbers or service tags or support tickets is to the logic that directs your IVR tree or call queue, the easier it is to build experiences that delight users. Siloed telephony and business software manifest themselves in ugly ways like having to repeat information to multiple agents or waiting on hold while your account information is retrieved.

We think if the code that makes your customers happy and the code that makes your phones ring can finally live in the same place, some pretty magical stuff can happen.

<comment><USER5> As always Rob, great answer :).

I think the part that made me scratch my head was the line where Jon said "It was so satisfying to make a physical phone ring!" which is funny when you take it out of context for a multitude of reasons. I hope you appreciated my quip about time travel ;).

Having the logic separate from the delivery may make sense for some applications and might not for others. We wrestle with clients all the time that want various elements of the platform either directly under their control or as far away as humanly possible. There's usually little rhyme or reason to understanding which components are supposed to go where or for what reason, but that's Telecom in a nutshell. When dealing with large carriers, the question of what goes in the firewall, and what stays out, is a complete mystery until right before you ink the contract.

To be fair, your point about siloed telephony and business software does ring a tad hollow when you talk about Twilio which is essentially a silo for business logic of a different color, right?

Once again, I do really enjoy these chats :D. I also admire the hard work your team does writing these blogs which I point to as a great example of developer evangelism. Your team does a great job of getting out there and showing off the tech. I especially like the edge case stuff, like jamming Asterisk onto a Raspberry pi and connecting it to an obihai ;).

<comment><USER4> I'm not sure the answers I have are always great, but really appreciate your praise of the devangel crew at Twilio. I'm very lucky to work with them.

Re: silos - You know, when it comes to all this cloud buzzword stuff, it definitely can feel like a shell game. Like you are moving a headache from one area to another for the sake of staying technologically trendy. But, I think a lot like you in the sense that the technical details matter.

In the case of an API play like Twilio, your logic stays in your app and that logic instructs how the call or SMS through a very simple interface. We don't host or hold anything for you - we just make the process of you telling us what to do as easy as we possibly can using the tools you already have.

APIs that are thoughtfully designed and carefully crafted are silobusters - they erase the painful demarcation lines of our software making the limits on what is possible less about how one piece of code talks to another, but why.

</comment></comment></comment></comment></comment></comment><comment><USER11> What do you need twilio, raspi and asterisk for?

You just need an ATA and a sip account like callcentric.

<comment><USER4> SIP From Twilio will send to any SIP solution you have, this was just a neat hack with one of our favorite hardware platforms.

</comment></comment><comment><USER12> What's with this on the blog background?

"SECURITY WARNING: Please treat the URL above as you would your password and do not share it with anyone."

<comment><AUTHOR> Weird, I have no idea. Thanks for pointing it out...will check into it

<comment><USER13> Seems to be a Facebook thing.

<comment><USER4> It was - bug with our social widget. Corrected now.

</comment></comment></comment></comment><comment><USER14> As a different configuration, I'm looking for a free solution that would let me dial 800 numbers from a VoIP connected home phone.

I dial into a lot of conference calls and this would be an awesome setup. Just wondering if anyone else has tackled such a config yet?

<comment><USER15> I'm pretty sure sipgate supports free 800 calls

</comment></comment><comment><USER16> Where was this seven years ago when I had all the pieces of a decent Asterix server, minus the SIP provider? I had such plans then, but never got the last leg of the journey done. I wonder if my Sipura 1000 still works...

</comment><comment><USER17> What would be slick is if you did a soft phone on the RPi and skipped the ATA. Then connect the speaker, mic, keypad directly to the phones old internals.

<comment><AUTHOR> That's a great idea - perhaps for my next post! I liked the idea of the ATA though since it's more of a proof of concept on how to interface Twilio with an older phone system.

</comment></comment><comment><USER18> Could this be deployed using OpenVBX?

<comment><AUTHOR> Potentially, though you may need to hack up a SIP module yourself.

</comment></comment><comment><USER19> I thought the whole purpose of Twilio was to not use Asterisk. Just saying. Great tech.

</comment><comment><USER20> This is ridiculously easy with Tropo. You plug in an ATA, register it and it works. We did this with an ATA to Rural India that forwarded local calls from a toll-free number to Tropo for an IVR. Works a treat. No computer needed.

What a waste of time with this Twilio garbage.

<comment><USER21> True that, Tropo just needs a marketing team like Twillio has and the this would be more obvious to others...

</comment></comment><comment><USER22> Can't wait to resurrect my SI football phone!

<comment><USER4> Think I'm going to go with this:

[http://www.amazon.com/Crosley-Black-Candlestick-Phone- CR64/d...](http://www.amazon.com/Crosley-Black-Candlestick-Phone- CR64/dp/B0002Z2U6A/ref=sr_1_4?ie=UTF8&qid=1363813735&sr=8-4&keywords=novelty+phone)

<comment><USER23> I have an old Lego phone collecting dust somewhere that sprang instantly to mind when reading this. Great post!</comment></comment></comment>


The iPhone Killed My Creativity - <AUTHOR> http://readwrite.com/2013/03/29/the-iphone-killed-my-creativity#_tid=hub-hero&_tact=click+%3A+A&_tval=1&_tlbl=Position%3A+1 <comment><USER2> I can relate to this. I came up with the idea for my current side project while sitting in a waiting room for 30+ minutes with no phone, just me and my thoughts.</comment>


Arm co-founder: deals like Nvidia sale may undermine UK's tech vision - <AUTHOR> https://www.theguardian.com/business/2020/sep/14/arm-co-founder-deals-like-nvidia-sale-may-undermine-uks-tech-vision <comment><AUTHOR> I can't imagine the UK competition bodies are strong enough to act, but they really should</comment>


On emulating hypervisors: a Samsung RKP case study - <AUTHOR> http://www.phrack.org/papers/emulating_hypervisors_samsung_rkp.html <comment><USER2> 54+ upvotes and no comments so I'll share some things I learned about ARM TrustZone (notes I took when studying it - very sorry about formatting - direct copy from a markdown file) - sorry if these are noob or very obvious takeaways (they certainly are compared to the phrack article, but here goes) ...

TZ is is not tamper-resistant hardware like eSE or UICC. And it is heavily implementation dependant (e.g. Qualcomm, Samsung, HTC, Mobicore etc)

> "To defeat the TrustZone one must first break out of the FriendZone" > \--unknown

\- TrustZone security depends on the provider who implemented it

\- not much existing security research unfortunately

\- can be abused to store rootkits

\- reading from disk can be exploited (eMMC Flash) due to parsing vulns

\- vulns in the Trustlets themselvs are possible (trustlets are isolated so damage is limited to the Trustlet)

\- attacks assume local admin access (root) since you need ability to issue SMC instructions

\- arbitrary code execution can probably be ignored since very limited, otherwise no ability to interact with TrustZone

theoretically:

\- SCM Command structures can be abused (kernel sends malicious command buffer which might cause integer overflow, e.g. > 0xffffff)

\- SMC request to exploit integer overflow which causes QSEE to write response header to arbitrary secure memory!

\- resulting hopefully in arbitrary secure code execution (only theoretically)

\- not so easy to exploit, however QSEE memory layout is known. Its image resides unencrypted on eMMC flash and is loaded at known physical address. A determined attacker can clobber part of a function pointer in secure memory to point to non-secure memory under control of attacker (e.g. payload)

but in practice:

\- it's a dead end since QSEE has mechanism to prevent TrustZone execution from non-secure pages (XPU?). This is undocumented and so remains only a theoretical attack for now.

however, you can achieve glory with attacking SMC Table Extension:

\- enumerate SMC handlers, and eliminate those that don't write putput, then chose best option based on task at hand. In SMC they are variable length (struct smc_entry), so you can actually iterate through table using num_tags to calculate entry length and matching against smc_num.

\- Essentially if you use arbitrary secure memory write to modify num_args filed in SMC table entry. Then expand size of entry so iterator jumps to supposed next entry in attacker controlled con-secure memory, and create fake entry to call arbitrary QSEE functions with arbitrary arguments!

\- One could find memcpy() and copy all of secure memory to a non-secure buffer, break all DRM/secure key storage, disable TIMA, or invoke OEM specific functionality (unlock bootloader permanently and/or install rootkit invisible to kernel)

\- now you have total control of EL2 TZ and hide malware which can never be found by the OS :)</comment>


Ask HN: How much wealth do I need to retire at 65? - <AUTHOR> Are there some rules of thumb that can reach a plurality of consensus here?
I'm hoping for some simple phrasing like "20x your current annual income".
Or do I need to be a legislative-prognosticating actuarial economist to even guess? <comment><USER2> Your money, properly invested, should grow, even if you invest conservatively.

So you don't need to draw down your principal to pay your living costs.

Let's say you spend $100K per year, and you can earn 10 percent per year, then you need $1 million.

But you don't even need that much, because there's no reason to die with $1 million in the bank.

So it's probably some kind of calculus problem, an integral or a derivative, or something.

And maybe you can do better than 10 percent! ;-)

<comment><AUTHOR> I thought this article was interesting:

[http://awealthofcommonsense.com/worlds-worst-market- timer/](http://awealthofcommonsense.com/worlds-worst-market-timer/)

</comment></comment><comment><USER3> One kicker that no one seems to address: 401(k) disbursements are treated as ordinary income for taxes. Up to 86% of Social Security is taxable depending on income. Therefore, you get a double whammy tax-wise from taking out money from your 401(k)... you pay tax on it and it triggers tax on your Social Security income. It quickly puts you up into the higher tax brackets too.

</comment><comment><USER4> 25x your annual expenses.

</comment><comment><USER5> Why don't you find a financial advisor and ask them.

<comment><AUTHOR> I found that financial advisors help you ask yourself questions - they don't give answers. It's almost like psychotherapy.

"Do you think Social Security will exist? We can model your retirement both ways..."

"How much risk do you want to take?"

"How much do you think you'll want to spend in retirement?"

"How much do you want to help your kids go to college, and how much do you think that will cost?"

Yeah, great, thanks for costing me money and just asking me fairly obvious questions - that are almost impossible to answer.

<comment><USER6> Because all these questions make an enormous difference in determining what your X number will be:

1\. If you believe you can live on $5000 a month then you need to know there is $5000 a month available to you. If you believe social security will exist and you believe you will get about $1000 a month from that, then you really only need to come up with $4000.

2\. Would you like to have just X in the bank at age 65 or do you prefer to have X + Y, just in case of emergency? If X is your maximum what is your minimum number you would take? That's your risk.

3\. Are you looking to travel extensively, buy a nice home on the water, give to your kids, grandkids, etc...? These all again impact X. And while you may not know the answer for certain, you should at least have a general idea of what you would like to do since you are obviously trying to plan for retirement.

4\. Simple question, are you going to help your kids with their education or not. Nothing wrong with either answer, but knowing the answer will impact your X number.

So going back to your original question of how much wealth do you need to retire at 65, it really depends on what you plan to do when you turn 65. Do you plan to live in a small home that is paid off or purchase a new home, do you plan to have kids or grandkids, will you drive a car, do you plan on being married, do you want to travel at all, I can go on. The point is there is no single answer to your question. I could probably easily retire with $1M in the bank and never look back. But a friend with 5 kids will probably need a whole lot more.

<comment><AUTHOR> 1\. But my belief in social security has zero impact on whether I will actually have social security. Which is why I asked in my question if I need prognostication skills in order to plan my retirement. That would seem to be an unreal expectation - that I can accurately predict whether or not I will have social security available to me, at which age, and with what payouts. I would need to predict multiple federal elections, would I not?

We're not discussing that I must also predict inflation, health care costs (or socialization), and the likelihood of various markets crashing or exploding... including housing or renting...

2\. That's not a REAL question. The real question there is, can we come up with ways to save more now, while maintaining my current comfort at adequate levels, with an expectation of future happiness? Because OF COURSE I'd like to have X + Y. The ways to try to achieve that are to save more, or risk more. BUT, you're asking me to establish my risk level, given my GOAL of reward. That's like starting by asking me how much money I want to win in Vegas as the first question. The FIRST question!

3\. Again, those are not real questions. The closest to a real question there is, do I want my percentage of pleasurable spending to increase or decrease, relative to my current spending. Sure, I can TRY to consider the things you've brought up - but again, as I complained, I would need prognostication skills to come up with remotely accurate answers to any one of those questions, let alone a slew of them.

4\. Okay, I'll pay for my daughter's education 100%. Can you tell me how much that will cost? Oh, you need to know what school she's going to? Well, hmm, I can try to estimate her SAT scores, but she's currently in DAY CARE. Again, this is not a real question. I would need prognostication skills to know whether college costs will quadruple, in CONSTANT DOLLARS, or maybe college will be socialized and my daughter will get a STIPEND!

I don't mean to sound arrogant, insulting, and condescending. I really don't. Sorry. Sincerely, sorry.

But I reject the premise of why you're asking the questions. "How much will you spend on socks?" "How much will you spend on hats?" ... "Okay, let's sum all those things up! TADA, you'd need to make twice as much as you currently make, and save 100% of it to achieve that goal!"

The first rule of data is to know how it's going to be used. Yes?

I do not believe you have a formula, where you can punch in my answers to your questions, and then achieve a measurably correct confidence level in my future, self-reported happiness with the outcome.

Since you don't have that formula, why are we gathering individual numbers that we will pretend to plug into it?

And yes, they're all great things to consider. But I do not believe you that considering each of them carefully will allow me to come up with a plan that is remotely likely to succeed. "Everybody has a plan until they get punched in the face." -Mike Tyson

...

Instead, I think it makes much more sense to look at the past. Let me filter huge amounts of data, by my known demographics... And see the histogram of self-reported happiness, for people who had given amounts of wealth at retirement.

1\. $X of income at Y age

2\. Spouse at retirement or not

3\. X kids, at Y age

4\. Retire at age X

5\. Live and retire in the Mid-West...

Allow me to see confidence intervals. High and low graphs, based on recessions or booms... Constant dollars only, please.

I mean, isn't AARP capable of collecting this data, and distributing it in meaningful ways to pre-retirement people?!?

...

And again, really, honestly - the three biggest things that are going to affect my retirement, in rough order are:

1\. Life expectancy for me and spouse (My grandfather died before reaching retirement. My great-grandmother died at 101y 6m.)

2\. The economy

3\. Percentage rate of our saving, relative to our income

To really predict 1 and 2, I would need to be a legislative-prognosticating actuarial economist. And 3 is going to be determined by me, limiting my current happiness, with the hope of future happiness.

<comment><USER6> The point of my post was that in order to answer your original question you need to at least consider what you want out of retirement including the type of lifestyle you intend to live. It doesn't matter the questions asked (i.e. whether social security exists, whether you want to travel, etc), the point is to consider what YOU want out of retirement. Nobody can answer your original question specifically as there is no one specific X dollar answer to the question. What my definition of living comfortably in retirement is and what I could retire on is most likely going to be completely different than yours.

You don't sound "arrogant, insulting, or condescending", but the way you come off in your answer is that you want someone to give you a specific number (let's say X) without providing any context as to what you expect out of your retirement. You come off sounding as if you don't want to take anyone's advice or answer anyone's questions yet you want them to answer your question.

You don't have to predict anything or know the specific answer to any question, and I think that is where you are misinterpreting the questions. There is no right or wrong answer to the questions, they are only asked to gather details about your perceptions. Your answers are then used to compare to known financial data to determine a good retirement amount. They are "real" questions. If you have no intention of having kids or being married, that is significantly going to impact the amount of money you need to retire. If you plan to sell your belongings and live in an RV and travel the country till you die that is going to impact the number. While these may change down the road, you plan for the future on what you know now. You say you plan to live/retire in the mid-west. How do you know that is not going to change in a year.

From my own personal perspective I plan for my retirement based on what I foresee my future holding. I work with a financial planner to determine a good investment strategy based on those plans. However, I am consistently reevaluating those plans on an annual basis. My adviser asks me similar questions. But he also uses freely available data on what current retirees are doing based on the economy. He evaluates my strategy against the pros/cons of what current retirees are seeing in their retirement. I don't know how much my kid's education will cost, but I do know I want to pay, or at least help pay, for that. I base my planning number on current costs and add a cost increase for each year based on previous history of cost increases. The questions are not meant to be answered specifically, they are simply meant to get you thinking about your future and where you see yourself. You are right no one knows what it will cost in the future and you are right you can make assumptions based on past numbers. However, in order to use the numbers from the past you need to know what numbers to use. Thus the point of the questions.

With all that said, I am not going to go back and forth with you here. I am not a financial planner. I can't answer your question specifically. I'll leave you with this: [http://money.usnews.com/money/blogs/on- retirement/2015/06/25...](http://money.usnews.com/money/blogs/on- retirement/2015/06/25/5-retirement-lessons-from-warren-buffett)

</comment></comment></comment></comment></comment><comment><USER7> given that you may live forever according to some futurologists?

</comment><comment><USER8> How much do you spend?

<comment><AUTHOR> Let's call it X, shall we?</comment></comment>


Design - The Demise of 'Form Follows Function' - <AUTHOR> http://www.nytimes.com/2009/06/01/arts/01iht-DESIGN1.html?_r=1 <comment><AUTHOR> The author doesn't understand form or function too well and it's remarkable at how he equates moving towards more intuitive ways of doing things as the "The Demise of Form follows Function." Weird part is that it's in the New York Times.

</comment><comment><USER2> To me, form follows function means no unnecessary ornamentation. This doesn't mean NO ornamentation, one of the things persistently misunderstood by engineers is that all ornamentation is frivolous. What it means is the ability to carefully consider and justify each design decision that you make and to not be mindless about your design.

I think the NY Times article had somewhat of a point. Sure, the original iPod needed to have a wheel and a screen and be easily held in your hands but it really could have looked like anything apart from that. The loosening of constraints upon design is at both liberating and slightly terrifying for those who believe in form follows function.

</comment><comment><USER3> What many design critics such as the author are slow to realize is that the interface is _part of_ the design, and it still follows the same principles, just in a new context.

For example, the interface of the iPod Shuffle is meant to be operated without looking, often while moving, hence the form has just one main button located in a stable stable position operated by squeezing instead of pushing. Even the process of syncing with a computer defaults to requiring no interaction beyond plugging it in.

<comment><USER4> I'm sure the author understands that, but the point is that you have to know what you are doing before you operate it. Give any schmuck a Sony Walkman and a Fresh Prince cassette and they can get it playing in just a moment (if less). These are the challenges of creating more functionality in smaller devices.</comment></comment>