skysight-inc/HackerNews huggingface dataset:
For those who missed other criticisms, see also:

Musk's Hyperloop math doesn't add up

https://news.ycombinator.com/item?id=6232573

Musk's proposal won't actually get riders to the downtowns of Los Angeles or San Francisco. It can only carry around 10% of the capacity of the California High-Speed Rail. Additionally, it will bypass other population centers, like Bakersfield, Fresno, and San Jose. Building a truly workable Hyperloop, if it's feasible at all, will be significantly more expensive than Musk claims. It might even be more expensive than the California HSR project. And Musk's proposal leaves a lot of questions unanswered.

And:

Loopy Ideas Are Fine, If You’re an Entrepreneur

http://pedestrianobservations.wordpress.com/2013/08/13/loopy...

The proposed relationship between curve radius and speed in the Hyperloop standards is for a lateral acceleration much greater than 4.9 m/s^2 in the horizontal plane: 480 km/h at 1,600 meters is 11.1 m/s^2. This only drops to 5 m/s^2 after perfectly canting the track, converting the downward 9.8 m/s^2 gravity and the sideways acceleration into a single 14.8 m/s^2 acceleration vector downward in the plane of the capsule floor, or 5 m/s^2 more than passengers are used to. This is worse than sideways acceleration: track standards for vertical acceleration are tighter than for horizontal acceleration, about 0.5-0.67 m/s^2, one tenth to one seventh what Musk wants to subject his passengers to. It’s not transportation; it’s a barf ride.

The barf ride that is as expensive as California HSR and takes as long door-to-door is also very low-capacity.(...) The proposed headway is 30 seconds, for 3,360 passengers per direction per hour. (...) HSR can do 12,000 passengers per direction per hour: 12 trains per hour is possible (...)
But even 30 seconds appears well beyond the limit of emergency braking.

And also:

Hyperloop proposal: Bad joke or attempt to sabotage California HSR project?

http://stopandmove.blogspot.fr/2013/08/hyperloop-proposal-ba...

High Speed Rail between downtown LA and downtown SF:
2 hours, 28 minutes

Hyperloop trip between downtown LA and downtown SF:
1 hour from LA to Sylmar via Metrolink
20 minute transfer
35 minutes to Dublin
20 minute transfer
1 hour 10 minutes from Dublin to SF via BART
Total: 3 hours 25 minutes

The project also doesn't even attempt to price the connection into LA or SF. That's where the high costs are.

Amusingly enough, the California HSR budget for the Central Valley is under $10 billion. Ie, in the same ball-park as this proposal. The reason the HSR project is going to cost $60 billion is because it has to face an uncomfortable truth; actually getting to LA and SF is expensive. Very expensive.

Is Elon Musk's s mega-announcement really just a last-ditch attempt to sabotage the California High Speed Rail (HSR) project, rather than a serious proposal to revolution travel? Something smells very fishy.
arethuza ninja-edited his comment after my reply, his initial
reply was simply "So what about SpaceX and Tesla?", which didn't
make a lot of sense to me.

But my point still holds, because you're good at making rockets
and electric carcs doesn't automatically make you an expert in
high speed train infrastructure, so I don't really think that's a
valid argument.
At least one person was charged with murder this week due to the contents of a tweet.
So this only affects you if you change BCLK at runtime. Which is something that basically never happens unless you do it yourself explicitly. Dynamic CPU speed only modifies multiplier which does not cause this issue. This is a non-issue for 99% of people, it's only an issue if you are measuring your manhood on an internet website.
Good analysis but I think its missing a few key factors:

1) The risk profile of each investment. It may be the case that Instagram is a riskier proposition. Specifically, the likelihood of success of Instagram once it is funded may be smaller than the likelihood of success of a funded Hyperloop project

2) There aren't enough instagrams to invest in or they are harder to identify than the hyperloop type projects

3) Even though the percentage return may be lower than the hyperloop, in absolute dollars, the hyperloop has a higher return. For investors looking to put more of their capital to work, this is attractive.
I thought the Ruby VM already did invalidate() on things rather than checking, and that was a common practice on dynamic languages (doesn't the Objective-C runtime do this also?). I am really excited for this but agree that it is bittersweet the project is owned by Oracle.
Where Apple and Samsung get their customers
funding over a billion dollars is not remotely intimidating to the large VC funds

I think the idea is that some of the companies in the $1 billion fund will succeed and others will fail. But, funding a single company/public works project to the tune of $1 billion would give some pause.
Which is why I, a moderate libertarian, have reluctantly acknowledged the need for a legal maximum 30 hour working week; the evidence for market failure in this area is sufficiently overwhelming that I can no longer ignore it.
I looked very closely at Braintree but ended up not implementing them because of their €100 minimum per month. I don't understand how you say their API is complicated. It is well documented. The Ruby Gem also seems quite good and easy to implement. As you host the form and data is sent to Braintree there is also very little to get it up and running.
The Ideal Web Application Development Cycle
None of these apply to me: no $1m to start a business in US nor a company to open a subsidiary in US.

I'll have to go the visa/green card lottery way I think ...

As a summary I see I'll need a visa in any case. And that visa is very hard to get without bothering my clients with sponsorship & help.
Agreed. I think you're right.
Yes, it is plus interchange fees. And €100 minimum per month in fees.
Read some code at golang.org
You use expansion joints like these: https://en.wikipedia.org/wiki/File:Flanged_Rubber_Bellows.jp...

They're made of rubber, fiberglass and other flexible but strong materials. I don't know how well they'd handle the vacuum stresses but I don't think it'd be too extreme.
My understanding of his reasoning is that he does credit Musk with knowing things about thermal expansion, and it's precisely that combined with the hand-wavy treatment of it in the proposal that makes him believe that the whole thing is likely to be snake oil.

He's not really trying to have a reasonable argument, he's describing his thought processes around whether this is a project that is worth him getting involved in. There are a lot of bad ideas out there, and geniuses (if that is what Musk is) are no stranger to them (c.f. Einstein's wing design).

It's perfectly reasonable when faced with a huge number of proposals that take a significant amount of effort each to make an initial determination based on surface details. Sure you'll have some false negatives, but you'll have a bit more time to address the ones that really have a chance of going somewhere.
Quote: "The Timely Alarm Clock app team has created a new and novel way to set the alarm time."

Wait ... "new and novel"? Was this sentence contributed by the department of redundancy department?
Lead iOS Application Developer
It means you know a whole lot about thermal expansion.
> Most of us would probably stop programming if we had his never ending flow of income.

As far as I'm concerned, quite the opposite. I would keep coding but this time, without anyone telling me what to do.
The Japanese Bullet Train - Shinkansen [video]
This is amazing. Very much needed.
Not sure how this is uniquely applicable to Delhi. Sounds like this would be an issue pretty much anywhere in the world.
> How is that statement relevant here?

Because in real life (as opposed to, say, Star Trek), aerospace engineering and civil engineering ain't the same ballpark, ain't the same league, and ain't even the same flipping sport. [1]

[1] with apologies to Pulp Fiction.
I thought you were speaking more generally about investing not specifically about Hyperloop. My mistake.
It is well documented but they use a lot of terminology which makes it annoyingly obscure, and the control panel is very confusing if you don't know any accountancy vocab. There are far simpler alternatives which cost less and do the same things.
Abolish the NSA and give Edward Snowden a Parade
"This shit doesn't get a proof of concept built up in a dorm room over the weekend, and it's user base isn't going viral to signal interest in the product if there is no product to use until you're already $4,000,000,000 in the hole...."

Exactly. And on top of that, there is no making serious pivots. If you're an Instagram and you realize that people don't just want to share photos, they want filters, you can make that change in minimal time. In a Hyperloop situation, you're designing something that you're hoping to convince people that they want, and if you build it and no one comes, you're massively screwed.

Not to mention that Hyperloop would have a massive cost over-run--I don't care what his estimates are. The cost of land-use alone is going to be just outright insane. If you run a pilot in CA, you're going to blow through several billion just securing basic land rights, running years-long ecological and wildlife surveys, determining impacts to groundwater/rivers, etc.

Then the real work begins. This would make the Big Dig look well planned & executed.
Bitcoin recognized by Germany as legal tender
I feel the same way - it was an inspiring book but didn't suitably point out the difference between an unproven and proven founding team and how they can approach fundraising, which I believe caused parent (and me) to "get into the game" with unrealistic expectations.
I think there is an inconsistency in the proposal, because he clearly mentioned cumulative expansion (page 5 of the pdf https://docs.google.com/viewer?url=http://www.spacex.com/sit...):

A telescoping tube, similar to the boxy ones used to access airplanes at airports
would be needed at the end stations to address the cumulative length change of the
tube.

If you're absorbing all the changes in length at the pylons, you don't need to absorb cumulative changes.

Another reading is that the welded joints don't need to coincide with the pylons - that's just how it was constructed, not how it's supported. The tube ends up being continuous, with nothing special about the part of resting on the pylons, and move freely on rollers or similar. However, this reading also doesn't work, because he says of the dampers (also page 5):

These would absorb the small length changes between pylons due to thermal changes...

So, there's an inconsistency. But it doesn't seem like a big one to me, and not hard to overcome. And finding these bugs is one of the intended benefits of open-sourcing it. I haven't looked into the second finite analysis one, but though I looked for material consequences, it seems to be mainly a criticism of presentation.

It amuses me that after spending his talent, time and money (he mentions at the start that he's paying for his blog) helping Musk's proposal, this fellow vents:

I wouldn’t put my money, time, or talent in the hands of someone
who takes me for a fool.

Musk caught him monologuing.
ALEC - Corporate interests attacking schools
One thing I always think is worth mentioning in posts like this is that the above setup (and any setup using Selenium, really) is going to be super slow. More than one order of magnitude slow, when compared to direct HTTP requests.

It's only ever worth using Selenium when you literally can't do anything else to get your testing done.

Edit: Going through my bookmarks bar and found this, from 2008 - http://www.alittlemadness.com/2008/03/05/running-selenium-he...

Might help anyone if they run into issues.
Advanced WordPress Meetup being held in Downtown San Diego with 20+ RSVP'd
It might mean you should know that, but to the extent it does, that makes it more, not less, notable that your work fails to demonstrate that.
Responsive Design vs. Native Monetization
Increasing key length has been the main way to protect crypto from Moore's law. That law is somewhat predictable: we can now how much time a key can hold depending on ressources needed to crack it.

The real problem here: cryptanalysis advances like Joux's tend to create big leaps, much bigger than what we predict based on Moore's law.

And there's the problem that RSA 2048 is slow, and RSA 4096 is so slow that it's impractical...
In doing some research online I found out that other American inventors have had similar designs and proposals for a decade

Wikipedia mentions an American who proposed something like this as early as 1867, and British scientists had played with the idea even before that. http://en.wikipedia.org/wiki/Pneumatic_tube#In_public_transp...
I'd say the difference is how long they're "resting". Taking a weekend or vacation? Wonderful. Haven't had a job in a year and not really trying to get one? Idle.
Agreed, this is just far-left polemics. Can we at least have some link to technology, however tenuous?
Apple's Ecosystem Helps Deliver a Winning Customer Experience
Why do we continue to work 40+ hour weeks when 15 would suffice? The answer is quite simple -- over the past tens of thousands of years, the primary survival pressure on our gene pool has been scarcity, and thus we are genetically -- not socially -- programmed to want to work.
It's very hard to find a good team who can work for free or cheap. It's a founders job to do very hard things.

Oh and anyone working full time on sweat equity should be a founder and if you're not calling them a founder you shouldn't have them on your team at this point.
Why Innovation Is Still Capitalism’s Star
> "Never invest in a business you cannot understand."

Which suggests a #10 on the OP's list: investors don't understand technology very deeply or widely. The last boom was the web, so we have an over-population of investors who understand the web (to the extent that they "grok" any tech at all).

MVP and user traction makes a lot of sense for web startups. Web startups are low-capital, in many cases so low capital that they can be funded by someone working on the side as a Starbucks barista. It's popular because a tiny team or even an individual can often build something minimal, get traction, and then make what amounts to a gigantic ROI. Imagine said Starbucks barista doing a proof-of-concept that gets a million users... the ROI there for the individual is insane (like thousands of percent), and the potential ROI for the investor is quite large as well. Web startups generate a lot of very real rags-to-riches stories.

But this formula simply doesn't translate to anything that is at all capital intensive. Basement hackers are never going to prototype new mass transit solutions, try to mine asteroids, design 3d printers to print human organs, or build a fourth-generation molten salt reactor. Not gonna happen.
No, your argument is mixed up and confused.

IP is irrelevant and not good evidence of
anything. The IP address used by
3taps can be changed by the 3taps ISP
at any time for any reason.

IP can't be used for authentication.

With public key cryptography and
Kerberos, there are some excellent
means of authentication. If Craigslist
wants to use such authentication, fine,
and then they can effectively and accurately
block any given collection of users.

But usually a Web site, e.g., HN, offers
access to any IP address anonymously,
without authentication. In that case,
it's next absurd for the Web site to
complain about some person when they
have next to no good evidence on that
person.

Your "go out of their way" is wildly false;
all that had to happen was just their
electric company to drop power for
one second. My electric company does this
about once a week. Then the cable modem
will forget its assigned IP address
and, when electrical power is restored,
request a new IP address. The 3taps
people need not be aware of this at all.

Moreover, the ISP can have assigned the
banned IP address to someone else,
Joe, not involved. Then Joe's usage
of the Web site is no evidence against
3taps.

Maybe 3taps knew that the Web site did
not want them to use their site,
but more importantly the site had
no good evidence, at least not from IP address,
if 3taps was using
their site at all or not.
I really like this. If I was going to suggest a change/tweak, you might want to define the chart colors based off what is in the compare boxes rather than going with Highcharts' defaults. When looking at a compare and adding additional entry(ies) you need to constantly look back to the legend.[1][2]

[1] http://www.ryan-williams.net/hacker-news-hiring-trends/?comp...
[2] http://www.ryan-williams.net/hacker-news-hiring-trends/?comp...
I am no expert on such things, but it seems to me that Dr. Drang has a very basic misunderstanding or lack of imagination. He seems to assume that Musk intended for each section of tube to physically be touching, when instead Musk intended to leave gaps between, to account for the expansion.
I've written about this before. The problem is that any critique of Musk on HN is met with extreme opposition. Almost like the other HN meme: all corporations and CEO's are greedy except for Apple and Jobs (and probably Tesla/SpaceX/Musk).

Well, I'm glad people are now seeing that this is not a serious proposal. I actually think this is an elaborate marketing move. Not much Tesla news lately.

While I don't have a PhD in Physics, I do have a PhD in Having Designed and Built Lots of Shit. I have touched enough disciplines outside of my EE training to have a pretty good reality meter when it comes to engineering.

Thermal expansion, earthquake survivability, cost and plausibility were probably the first few issues that stood out to me.

Thermal expansion is a huge problem. It is also a first year college physics problem.

What is not mentioned in this article is thermal shrinking! I am surprised the author did not focus on that a bit.

And then there's the more complicated problem of differential thermal effects. Put another way, you can have a portion of the tube pushing while another portion would is pulling.

The bottom line is that there's a need for tube-to-tube gaps bridged with compliant material. This would localize thermal effects to a single tube and prevent propagation up and down the system. Welding is out of the question.

The superficial treatment of earthquakes is also of concern. Many years ago I devoted a non-trivial amount of time to understanding earthquake physics because of a large project I was heading that required earthquake survivability. I learned just how serious these events can be. There are at least four effects to deal with: ground acceleration, structure resonance, amplification of acceleration magnitude within structures (resonant "snap"). This isn't the right venue to discuss this at length. You'd have to design for ground accelerations in excess of 5 g, ground displacement in the one to five meter range and "snap" accelerations in the 10 to 50 g range (guessing the high end). And do so for six degrees of freedom (xyz and the respective rotations).

Just yesterday I drove along a 100 mile stretch of the Golden State freeway. I took note of the viability of installing support columns every 100 ft. Let's just say the very idea does not align with any imaginable reality.

Great marketing though. No need to deliver anything real. Thise not equipped to understand the real engineering and business problems will surely elevate Musk to even greater genious status and recoil at the very idea of criticizing him. My prediction is that somwhere in Washington someone is trying to figure out how to throw a few hundred billion dollars at this and use it for political gain as well.
> I can buy 2[1], but what's your evidence for 1? I mean, look at the decline in U.S. agriculture jobs over the past century in inverse proportion to agricultural output.

Machinery, automation, and corporate food production has a lot to do with why people work less on farms. However, overwhelmingly agriculture in the US uses migrant labor that is often paid very little wage when workers are needed.
All the research on the subject shows incontrovertibly that 5 is way too young for video games.
It seems to me there's an awful lot of people with engineering knowledge getting all uppity about how (in a presentational sense) the proposal was presented, along with what was presented.

Criticisms about what the proposal claims are useful. Criticisms about how it's redundant to mention that a diagram is magnified or that a slightly less common term is used to describe an element is used are unconstructive and puerile.

I'm interested in criticisms of hyperloop, but all the ones I've seen so far have seemed to carry some bias, if the manner of the criticism is to be taken into account (and to a layperson without the ability to accurately and quickly check their assertions, how can it not?). How are we to know if this perceived bias is affecting the more coherent criticisms or not?
I grew up in Delhi in a middle class family but I went to a school full of kids from Upper middle class to filthy rich families. The kids who came from old money families were actually fairly down-to-earth and some of them have worked hard to build their own businesses and startup (of course, having a cushion to fall back makes it easy to take risks but still, it still admirable to have the desire to do something on your own.) But then there were kids from the 'new money' families born out of the new economic boom. These were the ones who drove daddy's expensive cars, flirted with prostitution, drove through traffic stop lights (like it was an inconvenience for them) at full speed.

The thing is that this breed exists in every city in the world - what exacerbates the situation in Delhi is that they don't have any regard for law and order. Couple that with the relatively weak and easily bribed police force - you have these kids running over pedestrians and getting away with it, shooting waitresses in the head when they deny them drinks after closing time (as an extreme example)

I don't care about their depression problems, a good ass whooping can fix that, I care about the unsafe environment they create in the city.
Lol. Khalil next time post a bug of facebook in the black market and then they will pay better.
Interesting summary. I'm located in Germany and I'm thinking about switching from PayPal to some other payment provider.

Does anyone have experience with chargeback fees? PayPal doesn't have chargeback fees and I'm a bit worried that chargeback fees might have unexpected consequences. Many of my transactions are 6€ or 12€. When does a chargeback fee trigger exactly and how likely is it if you have a customer base of a few thousand?
JSC has a very stable external API and performs competitively (for some reason it always beats V8 on DOM manipulation stuff -- I don't know why v8/chrome haven't been able to make more efficient bindings).

It doesn't build outside of the WebKit tree, though... (but there are some scripts which should in theory build only jsc; I think they want all the deps to WebKit, etc, however).
"Math professor" probably means at the college or university level -- high school math is widely regarded as complete and utter BS.

I've taken... a rather significant pile of maths classes at this point (I'm majoring in it), and I've never felt like any of the college-level maths classes assigned busywork. I may not have liked the size of the workload (oh god, real analysis), but I've never felt it was unreasonable.
Two Petitions on Searching Cell Phones Reach the Supreme Court
You must be Mark Zuckerberg