Algorithms.js – Atwood's Law applied to CS101 - <AUTHOR> https://github.com/felipernb/algorithms.js

<comment><USER2> The commit message "Optimized performance of the GCD algorithm" piqued my interest. It's GCD, what's there to optimize?

I noticed the following code:

        while (b !== 0) { if (a > b) { a -= b; } else { b -= a; } }

This uses repeated subtraction (a -= b) to implement division with remainder (a %= b); imagine a=1e12+1, b=2.

Please don't do this in your code. If there is a built it instruction for division with remainder, don't reimplement it poorly in javascript.

<comment><USER3> This is the Euclidean algorithm for GCD, it's naive and simple. But if you see it more carefully, the commit that says "Optimized performance ..." contains just the lines:

      34      var tmp = a;
      35	  a = Math.max(a, b);
      36	  b = Math.min(tmp, b);
      37	  if (a % b === 0) return b;

to avoid the unnecessary repetitions if b is already the GCD

<comment><USER4> Still, this wouldn't help in the given case of a=1e12+1, b=2. What's the point of those four lines 34-37 -- these would be unnecessary if the code used "%" instead of "-" in the first place.

Edit: Also, if you stick to the original subtraction-based version of the algorithm, why adding that other optimization? That wasn't part of the original algorithm, either. This seems to be double standard.

<comment><USER3> Still this is an issue with the algorithm, not the implementation.

[http://en.wikipedia.org/wiki/Euclidean_algorithm](http://en.wikipedia.org/wiki/Euclidean_algorithm)

<comment><USER2> I think you misunderstood the Euclidean algorithm. The basic iteration is of the form

        gcd(a, b) = gcd(b, a mod b),

and there is no need to compute mod with anything other than %.

<comment><USER3> You're right. This is the subtraction-based implementation, the division-based is the original and better one :)

[https://github.com/felipernb/algorithms.js/commit/e5a04f9ad0...](https://github.com/felipernb/algorithms.js/commit/e5a04f9ad07256ef5cd86aa2fc772dc713381de3)

</comment></comment></comment></comment></comment></comment><comment><USER5> This reminds me of David Eppstein's fantastic PADS library [1] of algorithms implemented in Python.

[1]: [http://www.ics.uci.edu/~eppstein/PADS/](http://www.ics.uci.edu/~eppstein/PADS/)

</comment><comment><USER6> Whether its Javascript or any other language, I think writing algorithms is a great way of driving home certain concepts when you are learning algorithms. Its even more fun to use your data structures and algorithms to solve toy problems and see the difference. Obviously, this is not recommended in production where one must use battle-tested code.

I did a similar exercise when I was doing a course on Coursera in Python - [https://github.com/prakhar1989/Algorithms](https://github.com/prakhar1989/Algorithms)

<comment><USER7> If you like doing this sort of thing, there are a million little CS problems like this codewars.com

One cool feature of the site is that you can vote on solutions; this lets you see a lot of neat solutions to problems, and learn a lot about how to write clean code.

</comment></comment><comment><USER8> Only the one who reinvents the wheel learns how it really works. :)

<comment><USER9> I've never invented a wheel but I'm pretty sure I know how it works

</comment></comment><comment><USER10> Why is a Javascript implementation of some very basic algorithms interesting or noteworthy?...

<comment><USER11> See: [http://blog.codinghorror.com/the-principle-of-least- power/](http://blog.codinghorror.com/the-principle-of-least-power/)

"Atwood's Law: any application that can be written in JavaScript, will eventually be written in JavaScript."

It's kind of a joke thing.

<comment><USER3> Exactly! Also, many JS devs are clueless about CS101 basic things, it's a way to maybe make them a bit interested.

From the wiki ([https://github.com/felipernb/algorithms.js/wiki](https://github.com/felipernb/algorithms.js/wiki)):

      The intention is to blend academic concepts with the
      JavaScript bits of insanity, applying Atwood's Law to CS101.

<comment><USER12> What percentage would you say are clueless about CS101 basic things?

<comment><USER13> I would estimate 75% of Web developers are "clueless" about algorithms and data structures (although that's a fairly strong word).

<comment><USER12> This seems high...I just went through a bunch of front end web developer interviews and nearly everyone I was asked some algorithm or data structure question. Maybe it's just NYC or maybe it's where I was applying.

<comment><USER14> It's likely an artifact of the jobs you're applying for but also consider that they're might be asking those questions now because in the past there were too many applicants who weren't qualified. It's only been fairly recently that front-end development has been taken more seriously as an engineering discipline.

<comment><USER12> I get the feeling these days most JS developers at least professional ones aren't totally clueless about algorithms and data structures.

</comment></comment></comment></comment></comment></comment></comment></comment><comment><USER7> Why not try to implement the iterative O(ln(n)) Fibonacci from SICP (Ex 1.19), rather than the old O(n) one? Or the Matrix exponentiation solution (he'd probably want to implement iterative matrix exponentiation too... doesn't look like he knows clearly how to do this)? [https://en.wikipedia.org/wiki/Fibonacci_number#Matrix_form](https://en.wikipedia.org/wiki/Fibonacci_number#Matrix_form)

<comment><USER15> Considering that the Fibonacci sequence is exponential, and hence the Nth Fibonacci number contains O(n) digits (well, in any sane base at least), you cannot compute the Nth Fibonacci number in under O(n) time.

<comment><USER7> Given the guys programming in Javascript and not using arbitrary precision arithmetic, he's always using 64 bits and representing his numbers as floating point, so I don't think you are reasoning correctly about the asympototic complexity here. I mean, if you _really_ want to argue this, then to quote Leibniz: "Calculemus!"

The javascript solution presented does everything in O(n) arithmetic operations, and the SICP way does it in O(ln(n)) arithmetic operations (actually, there are a lot of ways to do it in O(ln(n)) operations).

<comment><USER16> If we're going to stick to a fixed precision numbers, and we're just out to score maximum internet points, you can do it in O(1) by just computing out a table in advance, and for not much storage space since the series grows exponentially.

I mean, if we're going to screw around with the Os let's do it properly.

</comment></comment></comment></comment><comment><USER17> Why is this even on hn? Are you kidding me? I have some college projects too you know...

<comment><USER18> Great, let's see them</comment></comment>


With or without AT&T/T-Mobile merger, Sprint already lost - <AUTHOR> http://www.bgr.com/2011/09/06/with-or-without-attt-mobile-merger-analyst-says-sprint-already-lost/

<comment><USER2> _the addition of the iPhone 5 could do more to increase smartphone sales among Sprint's current subscriber base — and put more stress on the carrier's network thanks to its unlimited data plans — than it will to attract new business_

As a long-time Sprint customer (10 years), this is the most worrisome part about the impending iPhone 5 launch. All those Sprint customers who resisted the urge to get a smartphone, or who have BlackBerry, WinMo, or early Android devices whose contracts are coming due might jump to the iPhone. That could be disastrous for Sprint's network, since iPhone users have been known to be very data-hungry.</comment>


Indian Startups Vie to Win E-Commerce Battle - <AUTHOR> http://www.wsj.com/articles/indian-startups-vie-to-win-e-commerce-battle-1445494067?mod=e2fb <comment><USER2> One of my classmates has worked with several of these, starting with Myntra, moving on to Jabong, Hopscotch and Lenskart (by Flipkart) before moving on to becoming an EIR at some VC firm. According to him, most of these are operating at hair-trigger margins and it is the funding that is keeping them going, waiting for the day when they can either increase prices and still win or make enough volume to become profitable. The main wildcard is the internet penetration and the transportation structures in tier II and tier III cities - if they can manage deliveries at scale for cheaper costs to enough people, it should work out for them. Otherwise they will all lose to local stores anyway which have decades of inventory management skills.

<comment><USER3> Personally I think the real opportunity is building the tech to enable these local stores that you mention. Selling tech is much more scalable and higher margin and you take advantage of the existing delivery networks + customer relationships.

You would still have to eat costs for a few years, but long term I think those are the teams that will build the really significant companies.</comment></comment>


Twitter cuts its default rate limit from 350 to 175 - <AUTHOR> http://dev.twitter.com/pages/rate_limiting_faq

<comment><USER2> this kind of thing is the reason you can't base a business off Twitter (and expect to sleep soundly at night).

make Twitter apps for fun. not for profit.

<comment><USER3> Making Twitter apps for profit is fine, just don't depend on it.

</comment></comment><comment><USER4> It is far better for twitter to rate limit the API to a level they can handle, than to get themselves into an unstable situation with fail-whales. The header says what the rate limit is so applications can adjust.

They're also limiting their own apps so it's fair.

I guess I don't understand why the default was set higher than they could handle in the first place.

</comment><comment><USER5> Just like old times! :)</comment>


Show HN: Make a Pros vs. Cons list (weekend project) - <AUTHOR> http://www.pros-vs-cons.com/

<comment><USER2> This is super. Nice work.</comment>


When your manager isn't supporting you, develop a manager crew - <AUTHOR> http://larahogan.me/blog/manager-voltron/ <comment><USER2> I've worked and had roles where I had a non-existent manager.

If it is really really that bad, it's a much better outcome to leave amicably versus fighting to fix the issue. Remember that software is a very small industry we all work together in.

There's no candid way to fix your manager's behavior if they are non-existent, or completely detached from their team. Especially if your manager's manager does not care or know.

<comment><USER3> Indeed. I did not have a ~great~ manager until my 3rd or 4th job, and if I had known people like that existed before I certainly would not have stayed as long in some of the earlier jobs.

<comment><USER4> I had a really great manager on my 1st job, but due to limited experience I did not recognize and appreciate it at that time.

Not that it would have changed my decision to leave, the commute was terrible and I wasn't willing to move.

</comment></comment></comment><comment><USER5> Huh?

If your boss isn't supporting you, GTFO. Either to another group internally or another company.

No offense, but most of this it putting lipstick on a pig. There's no cure for laziness or bad intent.

Don't waste your time with a bad boss.

<comment><USER6> I'm glad the poster, posted their article instead of this knee jerk reaction. My manager is a good person. This team deserves good workers. This company deserves more support than knee-jerk reactions such as "If your manager is more inexperienced than you, QUIT!" This is why our grandparents think we have no company loyalty.

<comment><USER7> "company loyalty" ... in programming? are you serious?

I hope for your sake that you aren't. If you are, you probably are already getting screwed and just don't know it yet. And it'll probably end with another disillusionment because the company sure as hell won't be loyal to you once the CEO can increase his exit-bonus by firing you.

<comment><USER8> Not all programming jobs are the same, and not all software companies have the same culture. There are a lot of jobs outside the startup bubble, and outside the US.

Europe has a much better workplace culture in general , and there is some loyalty between the worker and the workplace.

<comment><USER9> I would say that Company Loyalty is a dangerous thing. The Company isn't going to be Loyal to you. I happen to like my workplace, but I know that if the company is ever in trouble again they will fire me without hesitation. I survived 2 firing rounds already. I will not survive a 3rd one. I didn't quit till now because I was loyal, but I stayed because I was lucky.

Some have decided to quit just before the firing rounds, because we all could see it coming. That is "disloyal", but they are now employed again. That may have been the better decision for them.

All of this was in a European Company.

</comment></comment></comment></comment></comment><comment><USER10> This reminds me that networking and engagement are not only activities for gaining new business...but fostering a support group of people that you already know. Nice article indeed!

</comment><comment><USER11> > "I've been coached through changing my name, which is a gendered > professional experience that none of my male peers had dealt with."

How about ending that convention in countries that have it? In Belgium most people do not change their name upon marrying, and I do not see the point of doing so. Person X and Y marry, there's a contract already, no name change is needed for that.

<comment><USER12> Do any countries actually require it? I think in the US, UK and probably other western countries you choose to change your name and either the man or woman can change if they want - it's totally optional either way isn't it?

<comment><USER11> Not sure, but I'm baffled why people choose to do so. If you've published anything, for example, don't you want to keep your name attached to it?

<comment><USER13> A lot of professional women (in the US, at least) run into that problem-- They either don't change their name and deal with the social problems that entails or they change their legal name but still publish under their previous name and deal with the professional implications. Publishing under a new name is also an option, but, as you said, makes it much harder to get your work connected to you.

<comment><USER14> > and deal with the social problems that entails

Can somebody explain a bit on what social problems can women expect in US for not changing names?

<comment><USER15> The main social problem comes when you have kids: if partners have different names, the kids will have names that don't match one of the partners, or will need a hyphenated-combination of the two.

The ramifications of this will depend on how common it is for women to not change their names in your particular locale: if it's uncommon, there will be some confusion when people expect children and parents' names to match, as well as people wondering about whether the child is actually your stepchild, etc. Of course, those judgmental/insensitive reactions are inappropriate, but they do happen.

<comment><USER11> Kids name not matching is a much smaller deal than _changing_ your name.

Because it doesn't affect anything in practice what their name versus parents name is, a name is an identifier of a person.

Changing a name on the other hand gives practical problems such as for any copyrights, email address, source code, publications, etc...

<comment><USER16> > _Kids name not matching is a much smaller deal than changing your name._

That's easy to say, but that's just your personal feelings on the matter. My sister left her name alone when she got married, but changed her mind (and her name) when she got pregnant, specifically because she wanted her kid to have the same last name as her.

I would probably make the opposite decision if I were in her shoes, but it was _her_ decision, based on her desires and what makes her the most happy; not mine, and not yours.

> _Because it doesn 't affect anything in practice what their name versus > parents name is_

Depending on where you live, there can be social confusion and even a stigma. Maybe you're lucky in that where you live that isn't a problem, but that's not the case everywhere.

> _Changing a name on the other hand gives practical problems such as for any > copyrights, email address, source code, publications, etc..._

No one's saying there aren't practical problems, but if the name change is worth it to you, then by definition you have accepted that trade off as also being worth it.

</comment></comment></comment></comment></comment></comment></comment></comment><comment><USER17> Err you deal with a sensitive hr/ir issue like firing by talking too a random informal group or peers - this is screamingly unprofessional.

You should have proper training for this issue or at least consulted with hr or an employment lawyer.

</comment><comment><USER18> A bit of a digression, and maybe this is a west vs. east coast thing--I couldn't detect the author's location--but starting an email to one's manager with "Hey $name" seems disrespectful. Additionally, asking folks "please don't address me with 'Hey'" I imagine to be ticklish business.

<comment><USER19> How would you address your manager?

<comment><USER18> Always "Hi $name" or "Hello $name". "Hey" feels to me like a California-ism and just a touch too informal for email in particular. Whether the downvotes on my original comment support or reject this hypothesis, I cannot say.

<comment><USER20> I think it probably rejects your hypothesis.

I use it frequently with multiple managers and directors. It entirely depends on your relationship with the person. Sometimes you can cultivate a relationship where being so formal and subservient is unnecessary, if not counter productive.

Edit: Not in California, or the US.</comment></comment></comment></comment>


Why is my NTP server costing $500 per year? Part 1 (2014) - <AUTHOR> https://blog.pivotal.io/labs/labs/ntp-server-costing-500year <comment><USER2> Reminds me of when Netgear decided to use the University of Wisconsin NTP servers as the default in their consumer products: [http://pages.cs.wisc.edu/~plonka/netgear- sntp/](http://pages.cs.wisc.edu/~plonka/netgear-sntp/)

<comment><USER3> The most frustrating part of things like this, and that Snapchat issue, is the largest abusers could probably swallow the cost of their own NTP server usage as a rounding error to their bottom line.

</comment></comment><comment><USER4> I wonder if they somehow mistakenly joined their server to the region-specific pr.pool.ntp.org group[1]. At the moment, that pool exists, but has no servers in it.

So, if you were the only server in the pool, perhaps you would get a lot of Puerto Rican traffic?

[1][http://www.pool.ntp.org/zone/pr](http://www.pool.ntp.org/zone/pr)

<comment><USER5> Someone else commented in the article, but it's probably related to Puerto Rico ISPs using a NAT because of lack of IPv4 address space. That single ip is probably many many people.

<comment><USER4> That one doesn't make sense to me. Most people don't have ntp configured to point to ntp.pool.org...they are mostly PC's pointed at time.windows.com. And, the pool is big enough anyway that it would spread the load from a relatively small island pretty well. NAT could be a small part of it, but there's a different primary cause.

<comment><USER5> It doesn't necessarily need to be Windows making the calls. Cell phones use a NAT typically and there was recently an issue with Snapchat DDoSing NATs.

<comment><USER4> That's an example of a "different primary cause". It's not NAT in that case, it's an app using a library with terrible defaults.

</comment></comment></comment></comment></comment><comment><USER6> An interesting theory in one of the comments.

> I wonder if Puerto Rico has run out of its pool of IPv4 addresses. After > Europe and Asia, just this month Latin America as well, have exhausted their > IPv4 pools, many local ISPs have resorted to using NAT to deal with the > scarcity of addresses (of course, after years procrastinating IPv6 and > pretending that this day wouldn't come about). Given that the source is a > Puerto Rican ISP, and one of the offending addresses from a small /21 > network, it's possible that NAT is to blame. As ISP NAT increasingly becomes > more prevalent, this is going to be rather touchy to deal with abuses. For > is it an abuser or just several innocent users behind a NAT?

<comment><USER4> I'm not understanding why NAT would cause it. I could see something like a misconfigured forwarding DNS cache causing it. Where it only queries pool.ntp.org once, and continues returning the result in the same order (with pivotal's ip at the top of the list) to a large number of querying clients. Then, perhaps, if there are a bunch of natted clients behind one ip? NAT, on it's own, without some other contributing factor, shouldn't cause this.

<comment><USER7> NAT wouldn't cause it but hide that in fact those are many client all having the same source IP. Of course, that wouldn't explain why they observed a general increase in traffic.

</comment></comment></comment><comment><USER8> part 2: [https://blog.pivotal.io/labs/labs/ntp-server- costing-500year...](https://blog.pivotal.io/labs/labs/ntp-server- costing-500year-part-2-characterizing-ntp-clients)

<comment><USER9> I wish he'd explained somewhere how they leapt to examining virtualized NTP clients, or what they ultimately did (since there's no part 3 that I can find).

<comment><USER10> Virtualization and time sync have had notorious problems. One ugly work around was frequent NTP polling and adjustments. NTP has a min and max poll interval, and it determines how frequently it should poll _automatically_ based on how far it sees drift happening. If it drifts pretty fast, it will quickly gravitate to the minpoll value, which is exactly what they show in their first graph: tons of polling at the minfrequency for certain hypervisors.

<comment><USER11> I wonder, should this be solved with local NTP servers that resolve from the name pool.ntp.org?

<comment><USER12> I've found it to be good practice to run a single/few stratum 2 node(s) to serve local resources. To whatever degree, it's usually more important that these resources be more in sync with each other than with a satellite, which is fostered by having as few nodes as possible trying their luck over the internet to bogged down public stratum 1 NTP sources, instead configuring them to use a single source of time from a box more in its vicinity.

</comment></comment></comment></comment></comment><comment><USER13> Hats off to everyone contributing to public services like this.

My then company wanted to give back ny doing this many years ago and it was an eye opening experience. We had troubles almost immediately with utilization and script kiddies. The company ended up only doing it for a relatively short period and ended up making contributions to projects instead

<comment><USER14> Our student-run computing club added a machine to the pool and melted the University's firewall. Oops.

<comment><USER15> Honestly, that's the University's fault then. Properly configured, it should've had very little noticeable effect on the firewall (i.e. "permit udp any host 10.11.12.13 eq 123") as there's no need to do any inspection or tracking state ...

... unless they saturated the available bandwidth but, really, that's a different issue (although also preventable!).

</comment></comment></comment><comment><USER16> I think this is great look at walking through the analysis. I too experienced a huge spike in NTP traffic in 2014 but it was because of people exploiting NTP for reflection attacks to DDOS other parties. The forced me to use a GPS module and a Beaglebone Black as an internal time server (which has been great)

<comment><USER17> I have a few questions about that if you have a minute:

What GPS module did you go with and is it still available? Did you have problems getting signal inside (need to be by a window, run an antenna, etc)?

<comment><USER16> I used the Adafruit "ultimate" GPS module ([https://www.adafruit.com/product/746](https://www.adafruit.com/product/746)) which has the 1pps output and can connect to an external antenna. Then I got this antenna ([https://www.adafruit.com/product/960](https://www.adafruit.com/product/960)) and this adapter ([https://www.adafruit.com/product/851](https://www.adafruit.com/product/851)). Soldered a header connector to Beaglebone protocape ([https://www.adafruit.com/product/572](https://www.adafruit.com/product/572)), wired it to the serial port and PPS to the GPIO pin (just like this: [https://web.archive.org/web/20131209092059/http://the8thlaye...](https://web.archive.org/web/20131209092059/http://the8thlayerof.net/2013/12/08/adafruit- ultimate-gps-cape-creating-custom-beaglebone-black-device-tree-overlay- file/)).

I put the GPS antenna on my window sill, it has no problem at all staying locked. My plan had been to stick it outside the window but turned out not to be necessary.

</comment></comment></comment><comment><USER18> Because you use AWS and they charge insane fees for outgoing bandwidth.

<comment><USER19> This $500 would have been $60, on a Digital Ocean box. DO has 1 TB/month limit. Their usage was 300 GB/month.

<comment><USER20> [author]

Digital Ocean is a great deal! Thanks for pointing that out.

The reason I use {aws,azure,google} to host my NTP servers is that my day job is developing a VM orchestrator (BOSH) for Cloud Foundry, and BOSH doesn't support Digital Ocean yet (AFAIK). But that's a personal choice, and an admittedly expensive one.

<comment><USER21> What about amazon lightsail?

<comment><USER22> It also runs on AWS so even though they try to trick you into thinking you don't pay for bandwidth you do. Also small EC2 instances are throttled so their server would probably not function most of the time.

<comment><USER21> They include 1TB BW in the $5 instance, that's $90 savings.

</comment></comment></comment></comment></comment></comment><comment><USER23> I'm surprised there are no comments about the fact that these guys decided to run NTPD on a VM.

<comment><USER20> [author]

NTP runs fairly decently in a VM. Don't take my word for it — look at the graphs of my servers:

Here's my Google VM, notice the jitter is within +/\- 5 milliseconds:

[http://www.pool.ntp.org/scores/220.127.116.11](http://www.pool.ntp.org/scores/184.108.40.206)

Here's my Hetzner VM (Germany). +/\- 10 milliseconds, though I can't help but suspect the distance from the monitoring station (Los Angeles) may have more to do with it than being a VM:

[http://www.pool.ntp.org/scores/188.8.131.52](http://www.pool.ntp.org/scores/126.96.36.199)

Here's my AWS VM. Much worse than Google in that it's +/\- 50 milliseconds, but still good enough to pass muster with pool.ntp.org:

[http://www.pool.ntp.org/scores/126.96.36.199](http://www.pool.ntp.org/scores/184.108.40.206)

Here's my Azure VM. It's in Singapore, and I re-deployed it last night, so the numbers are still coming in, but it has a pretty tight distribution:

[http://www.pool.ntp.org/scores/220.127.116.11](http://www.pool.ntp.org/scores/126.96.36.199)

<comment><USER15> Everyone's needs differ, I suppose, so some might consider that "decent". 10ms -- or even 50ms -- might be acceptable for many (most?) use cases but not for me.

From a quick look, my own (stratum 2) server in the pool currently has an offset of just under 1/20th of one millisecond.

Regardless, thanks for contributing to the pool!

</comment></comment></comment><comment><USER24> Why are people joining VMs to the NTP pool? These servers should be identified by address space and blacklisted.

<comment><USER25> Why?

<comment><USER26> Because VMs themselves might not be able to keep track of time accurately (potentially inconsistent tickrate) the way that a bare-metal setup would be able to. That's why they should be mere consumers (as in sync their time to whatever the remote says rather than contribute to the pool).

<comment><USER24> Correct, unless you have a very specific VM configuration where you are truly dedicating a CPU/core to a VM, it's not fit for being an NTP server.

</comment></comment></comment></comment><comment><USER27> I ran an NTP server on a Raspberry Pi for some time.

The bottleneck I kept hitting was the 65535 NAT translation limit on my Cisco router, at which point, load was quite manageable on the Pi.

It's extraordinary how much traffic one cheap device could service.

</comment><comment><USER28> This is a 2 year old article. Where's the follow up? What did they end up doing?

EDIT: AHA! Part 2: [https://blog.pivotal.io/labs/labs/ntp-server- costing-500year...](https://blog.pivotal.io/labs/labs/ntp-server- costing-500year-part-2-characterizing-ntp-clients)

</comment><comment><USER29> Why would anyone run an authoritative time service on a virtual server in the first place? My experience is that system time suffers greatly from noisy neighbor.

</comment><comment><USER30> ... because it's hosted on the cloud and you have no amount of free bandwidth with your vps ?

</comment><comment><USER31> I'm not sure if I've missed it, but is the question (from the title) ever answered? The discrepancy between expected traffic volume and actual traffic volume is huge and seemingly unexplained.

<comment><USER20> [author]

My bad — I never wrapped it up. Thanks to the HN interest, I'll try to write Part 3 over the winter break.

The short version is this: it's gonna cost a couple of hundred dollars to run a 1Gbe NTP server in pool.ntp.org, but you can tweak the ntp.conf to save ~$100.

</comment></comment><comment><USER32> This is the Snapchat bug reported yesterday, right?

Incidentally, how is AWS dealing with the leap second next week? Google is going to have their time servers start to run fast around 20 minutes in advance of the leap second, so they're back in sync at 00:00:60 UTC.

<comment><USER33> Details on AWS at [https://aws.amazon.com/blogs/aws/look-before-you-leap- decemb...](https://aws.amazon.com/blogs/aws/look-before-you-leap- december-31-2016-leap-second-on-aws/)

</comment></comment><comment><USER34> Second part is here: [https://blog.pivotal.io/labs/labs/ntp-server- costing-500year...](https://blog.pivotal.io/labs/labs/ntp-server- costing-500year-part-2-characterizing-ntp-clients)

</comment><comment><USER35> It was mainly due to the poorly coded snapshat program: [https://news.ntppool.org/2016/12/load/](https://news.ntppool.org/2016/12/load/)

EDIT: this post was indeed from 2014. My bad then. however the same issue started again two weeks ago (~17 dec 2016).

<comment><USER20> Here is a visual representation of the affect of the snapchat broken-ness on my NTP server:

[https://cloud.githubusercontent.com/assets/1020675/21468123/...](https://cloud.githubusercontent.com/assets/1020675/21468123/ac026274-c9d2-11e6-8334-2f56e9c9d20f.png)

Note that inbound traffic which was steady at ~4k packets/sec spikes as high as five times as much. Also note that the snapchat traffic followed a circadian rhythm (much higher traffic during the daytime).

</comment></comment><comment><USER36> Could this have been the result of an NTP amplification attack? [https://www.us-cert.gov/ncas/alerts/TA13-088A](https://www.us- cert.gov/ncas/alerts/TA13-088A)

<comment><USER37> Article said no, because the traffic was symmetrical and not lopsided. If this had been part of an attack you'd expect to see far more outgoing bandwidth than incoming.</comment></comment>


Competition app - <AUTHOR> what do you guys think of a competition app for people to showcase their skills. I am building one right now. <comment><USER2> Are there multiple categories people can compete to be the best? How is one determined #1 or #2?</comment>


GitHub comments today showed as if they are from the future - <AUTHOR> https://twitter.com/search <comment><USER2> We just ran into this also. We're seeing comments left in the future, and floating out-of-order in comment threads as new comments are made.

Can't really find anyone talking about it, is bizarre.</comment>


Is Amazon Working Backward? - <AUTHOR> http://bits.blogs.nytimes.com/2009/12/24/is-amazon-working-backwards/?hpw

<comment><USER2> From the article, "A quick perusal of the comments shows customers repeatedly griping about"

Maybe if Nick Bilton wasn't in such a hurry he could write an article worth reading.

</comment><comment><USER3> Or the demographic of the purchasers changed.

The early adopters liked the product, it's novelty for first time ebook buyers is a grand feeling, When I got my ebook I used it every day for a month.

The positive reviews generate good press for v.2 so people are attracted to it. Not being early adopters the customers are a bitr more critical but overall are satisfied with the product, it still has a buzz.

The DX is a new format and is deliberately marketed into a smaller niche - this time to academics. Smaller niches and the buzz from the first two products mean higher expectations from a more demanding audience.

The room is filled with cats minus their skin, some of 'em aint happy.</comment>


Why have engineers run interviews instead of HR - <AUTHOR> https://www.wyeworks.com/blog/2019/06/07/why-we-have-engineers-run-interviews-instead-of-hr/ <comment><USER2> I feel like it's worth to do two separate interviews. One interview getting a feel for the interviewee's knowledge about the field done by other engineers. And one done by HR that makes sure the company is a good fit culture wise and that the applicant can work together with other people and so on.

<comment> java-man please explain "company culture" and how HR is better at judging whether an applicant "fits".</comment></comment>


The Story of Apollo 17 and Why We Never Went Back to the Moon - <AUTHOR> http://io9.com/the-real-story-of-apollo-17-and-why-we-never-went-ba-1670503448?curator=MediaREDEF <comment><USER3> The blunt reality is that us meatbags are utterly ill-suited in every way to exist anywhere other than Earth (or someplace very Earth-like), and it requires a staggering amount of resources to climb uphill against that fact. I'm happy that we went to the moon (a truly mind-blowing achievement), and I hope that a human someday walks on Mars; but in an age of robotics, manned space travel is no longer the optimal way to explore or conduct research. Even its utility as a PR stunt has rapidly diminishing returns.

The good news is that the ever-growing sophistication of mechanical devices gives our species incredible "virtual fingers" to probe and interact with the cosmos, whether for research, or industry (such as asteroid mining, and perhaps someday, long-term terraforming).

And of course, I hold out hope that our cyborg/android/AI great-grandchildren will someday roam the stars in a way that we primates can only dream of.

<comment><USER4> There is no foundation for this argument to stand on.

Besides the fact that sending humans vs sending robots isn't a zero sum game, we're also sending robots out with decreasing frequency as well. "We should be happy to just send robots" would be great if we were actually sending robots. Here's hoping China and India pick up the mantle when Oppy and Curiosity finally shut down, I guess.

The reality is also that we don't learn much science with practical benefits for the hundreds of millions to billions of dollars we spend on these probes. Of course, we also get wildly poor returns on investment for the hundreds of billions to trillions of dollars we spend (in the US) on defense and health care. What we've decided is that it's worth it to spend a small amount of our money on the exploration of our universe, that discovery can be its own reward (and if there's a small chance in practical payoffs down the line, even better). We don't need to see what the surface of Pluto looks like, but I'm pretty excited to find out about it. Dismiss that as PR, but apply it equally.

This argument functions similarly to the one demanding we solve all the problems on earth before we start spending money on space. It assumes a way of allocating funds that doesn't match reality and demands unrealistic requirements not imposed on the favored approach.

<comment><USER3> > Besides the fact that sending humans vs sending robots isn't a zero sum game

This is a good point. I'm certainly not advocating against humans going to space; I just think sending robots is a vastly better long-term ROI. And whether it's a hundred years away or ten thousand, someday a form of intelligent life will exist on this planet that is much better equipped (if not actively designed) to seek its destiny in the stars.

<comment><USER5> Human bodies :

* require a constant supply of oxygen. Which is available effectively nowhere except deep inside gravity wells.

* require a constant supply of water. Which is available effectively nowhere. H may be everywhere, but O is nowhere convenient.

* require G-forces to be between 0.8 and 1.2 for long term survival. Can tolerate very brief exposure up to about 4G. This means the vast majority of planets are effectively uninhabitable just for that reason. And harshly limits the maneuvers possible to get there.

* require a sun-like source of radiative energy with a certain minimum intensity (one of the reasons people can't survive on Mars without additional UV exposure)

* require the presence, in small quantities, of half the elements with an atomic number up to 26, and several found further on. H, C, N, O, Na, Mg, Al, S, Cl, K, Ca, Fe, and I. Some of these are not very common, and they may be very hard to find. Not finding them first means it becomes impossible to have kids, increased occurrence of things like cancer, and a few years later it becomes lethal.

* require gravity. Which is massively inconvenient for operating ... well, anything really

* require radiation shielding against solar radiation for long term survival that requires about a hundred kilometers of atmosphere or several inches of metal (if you're to survive long term, for short excursions less isolation can be acceptable, also in Low Earth Orbit (like ISS) you're still partially shielded by the earth)

* require radiation shielding for charged particles that is provided by the earth's magnetic field, but requires metal barriers in outside of those fields

* require the sun's plasma barrier around the solar system to weaken interstellar background radiation to the point that the earth's atmosphere/reasonable thickness metal can actually stop it.

* require to be inside the galaxy, again to weaken certain types of radiation

* require a minimum distance to any supernova explosion of around 50 light years to survive (or yet more shielding)

* require to be in groups of at least 50 for long term survival (or we won't have enough gene variation and die off over time), even though short excursions can use a limited number of people. This is the low end of the estimates.

* require to be in groups of 2-3 people at least even for short term excursions or there will be severe psychological consequences

* require the presence of large masses of bacteria to fulfill certain bodily functions the human body can't actually do itself (best - but not only - example being digestion)

* require the presence of bacteria outside of the body to create compounds that we can't make ourselves. Some of these cannot be stored for any length of time, you need to take bacterial colonies or, better yet, plants + bacterial colonies with you and let them grow.

This isn't a complete list by any means. Human bodies will never go very far from Earth.

<comment><USER6> In the cosmic sense, Mars isn't terribly far, at least, or far off on most of these, given potential technological progress over the next few hundred years. I'm pretty confident humans will briefly visit Mars before 2040, and will probably maintain a continual presence, even as meat.

<comment><USER3> My understanding is that Mars has a dead core and no magnetic field, meaning severe problems with radiation, and even if we melted icecaps and thickened the atmosphere, Mars' lower gravity and lack of a magnetic barrier to solar wind would lead to gas particles escaping to space, and the atmosphere eventually thinning again.

<comment><USER7> I think that eventually would be measured in centuries or more. If we are able to solve the engineering challenge of terraforming Mars in the first place this kind of continual housekeeping won't be an issue.

<comment><USER6> I wasn't thinking anything this ambitious. We can keep people alive in the crushing depths of the oceans for weeks/months/years at a time; the real limits there seem to be economic. We could do the same thing for tens or hundreds of people on Mars if we really wanted to. Living indoors/underground most of the time, dependent upon certain things being supplied from Earth (but otherwise some kind of closed cycle or local production for anything bulky), etc.

</comment></comment></comment></comment></comment></comment></comment></comment><comment><USER8> I've been trying to get this article some attention on HN, but it's fallen flat the three or so times I've submitted it. "The case for nuclear propulsion for spacecraft (2003)": [http://www.spacedaily.com/news/nuclearspace-03h.html](http://www.spacedaily.com/news/nuclearspace-03h.html)

The article's points are (a) there were some realistic strides towards long- term sustainable space exploration before the Apollo project, (b) the Apollo project was directly responsible for canceling funding towards these long-term projects, and (c) the Apollo project was nothing more than a machine to convert a huge quantity of cash into a one-time use spacecar to stick a pole in the moon.

It was particularly surprising to realize that there are, in fact, feasible ideas for real space exploration. Humanity just has to remember and decide to pursue it.

<comment><USER9> With respect, the comment that "the Apollo project was nothing more than a machine to convert a huge quantity of cash into a one-time use space-car to stick a pole in the moon" seems to drop an incredible amount of context.

I think the Apollo project (and Mercury, and Gemini, the programs which preceded Apollo) resulted in a massive amount of learning, technology development, progress in manufacturing know-how, etc.

Your thoughts?

<comment><USER8> How do you feel about the idea that microcontrollers would have been invented anyway, even if Silicon Valley hadn't established the industry? It's that kind of situation. The learning, technology development, and manufacturing know-how may still have came. We'll never know for certain, and I'm not trying to imply that the Apollo project did nothing for any of those things, but it was largely a political decision to cancel these long-term space exploration projects in favor of the US being able to thumb their nose at the Russians for a bit. (As opposed to those projects being canceled for scientific reasons like feasibility.)

</comment></comment></comment><comment><USER10> I don't believe we have a solution to human-vs.-machine question, which is better to go to space. On human side, many times both opponents and proponents of space robotics pointer out that for big exploration programs humans become more economical - as you still can't reproduce human abilities in space with robotics while spending the same resources, if you have big enough goals.

Humans have other advantages too. Majority of people in modern NASA workforce say that they become interested in space when watching human space programs. So far no robotic achievements have psychological impact equal to humans in space. Next, there is eternal "explorational" argument - you don't really "get" space into your domain until you're actually maintain physical presence in it. Unless you at least fly on LEO, you aren't in space. Until you fly to the Moon, you don't "use" it. Etc.

Next, while robotics is advancing with leaps and bounds, human spaceflight doesn't stand still. In 1990-s Dan Goldin, NASA administrator, ordered an evaluation of some options of going back to the Moon. The cheapest was using existing rockets - less than 30 tonns on LEO per launch - and the program was for less than a billion dollars. Note that a bunch of technologies used today in manned spaceflight are vastly superior to those used during Project Apollo.

Getting to orbit becomes cheaper and safer - SpaceX is another evidence to that, but it's not at the end of technical possibilities. When you get spaceflight cheap enough, there is no stop for curious individuals to go to the Moon in person. Same for Mars - at least.

What technologies will be employed for traveling in space - that's another matter. With cheaper and cheaper energy it will progressively make sense to make more and more safe - even if heavier - human spacecrafts. The more infrastructure in space we have - be it LEO stations, fuel depots on orbit, Moon-based fuel production, Mars navigational network etc - the easier it will be to launch both robots and humans. It's hard for me to see why we won't want to go.

</comment><comment><USER11> Why, in good old Keynesian terms, did spending 4 % of the total budget on what could be described as a New Deal for engineering and scientists, was there supposedly so little ROI? That seems to be the argument from this article - <USER2> did not go back because it was too expensive. But if it brought more benefits than it cost, surely the expense is worth it?

I would have assumed economists would be all over NASA's accounts and the impact on the national debt?

It just seems a great natural experiment for spending as an economic influencer.

<comment><USER12> The telos of America is not ROI. The conquest of the continent was not really about monetary returns. You should think of space as a new manifest destiny.

<comment><USER13> That's not really true. Many people and our nation became very rich by conquering the continent. What's the upside on the moon?

</comment></comment></comment><comment><USER14> Lots of interesting discussion here about space exploration, but I'd like to add a personal note. I grew up in Huntsville, Alabama, during the 60s, NASA's glory years. Huntsville is home to Marshall Space Flight Center, where my father, an electrical engineer, worked as a contractor, with Chrysler. He worked on parts of the Saturn V and, I think, Gemini. When the Apollo program shut down and NASA had to retrench, he was laid off at about age 50, along with many other scientists and engineers. Huntsville imploded. Some of the unemployed started high-tech companies, some found jobs elsewhere, many left aerospace entirely. Chrysler moved some operations there, but nothing was available for my father. Fortunately, he heard through a friend of a job at Goddard Space Flight Center, in Maryland. He got the job and we moved, taking a loss on the house we'd owned for twelve years. He spent the last 17 years of his career at Goddard. Aside from the bigger issues of Humanity's Destiny in Space, the end of Apollo had significant human costs and changed many lives, including mine. I work at Goddard now and have spent over twenty years of my career here. That probably wouldn't have happened had we not moved to Maryland in 1971, when Apollo ended.

</comment><comment><USER15> Some media company (Google, Alibaba?) might fill up the sunny side of the Moon with a grid of photovoltaic cells 1 kilometer apart, then charge money to flash advertisements back at the Earth. They'd make a killing during solar eclipses, it would be like the Superbowl!

<comment><USER16> You would also need batteries that can charge for two weeks of lunar day, and then last for the two weeks of lunar night. And you would need at least 15 million of them at that scale.

If you could squash each unit down to just 1 kg and reduce your cost to only $1M per kg to the lunar surface, the whole project would only cost $15 trillion, which is only about a sixth of the entire global economy.

It would probably be cheaper to erect a giant space-screen that selectively redirects incident sunlight through optical fibers in a nearer Earth orbit. Rather than turn the Moon into a billboard, build an orbiting billboard that is the same apparent size as the Moon. Or bigger. Really spoil the view.

<comment><USER15> Batteries on the moon could be used incrementally, sending only 100 up at first in a 10 x 10 grid, and flashing back crude pictures or ideograms, even basic movies of McDonalds burgers, so there's free cash flow early on. An orbiting billboard, however, needs to be built all at once before it's useful, so it's a bigger upfront investment. Moon batteries can also be placed strategically to blend in with the topographical features already there, so instead of a Man in the Moon, we see a Man in the Moon drinking a can of Coke.

</comment></comment></comment><comment><USER17> We didn't go back to the moon for the simple reason that there is nothing there for a human.

Mars is the same way, and there is little reason to send a human there - there's just nothing there for a human to do.

</comment><comment><USER18> It was a great achievement to send humans to the moon, but I don't really see the point in going again. Or in sending humans to Mars. It won't be a place where people can live. No matter what happens to Earth, there will still be areas on it (or in it) that are more habitable to life than anywhere else in the solar system (and beyond). We could spend more time exploring the inside of Earth (and maybe creating small colonies there) than on the moon or mars.

<comment><USER19> We should go to Mars for the same reason we should climb Everest- because it is there. Neil Tyson has spoken very eloquently about this. Having something to strive for inspires people. It inspires children to become scientists, engineers, people who do something that nobody has ever done before, go somewhere that nobody has gone before. And that has untold, unimaginable benefits for all of humankind: [https://www.youtube.com/watch?v=pUbOjZWjTLU](https://www.youtube.com/watch?v=pUbOjZWjTLU)

<comment><USER10> If both robotics and human spaceflight will become cheap enough, even the fact that, say, robotic flights are fixed times cheaper won't matter. You don't always refuse to get a cup of coffee just because it's several times more expensive than some alternatives. The absolute difference is small enough for you to just ignore the fixed relative difference.

</comment></comment></comment><comment><USER20> Sadly, the planets around us are pretty boring. There's no point really to go there.

</comment><comment><USER21> It's easy we never got to the moon in the first place.</comment>


Ask HN: Do you ever wish there were two copy-paste key pairs? - <AUTHOR> Like c1,v2 and c2,v2. I wish this all the time when I copy an import statement and then some code. <comment><USER2> I think clipboard managers can do what you want, they have a clipboard history.

</comment><comment><USER3> Yes. The X11 clipboard does something like this, and when you're programming, it can be useful.

Related, I'd also like more than one cursor in a text editor. I believe I recall some Tcl/Tk thing from the mid-90s that had more than one cursor, but I've been unable to find it.

</comment><comment><USER4> Could you explain the exact use case for this?

I'm intrigued but a little confused.

<comment><AUTHOR> There would be what we have: Command+C & Command+V but also Command+<some other letter> & Command+<some other letter> for the second pair.

<comment><USER4> So if I am understanding correctly, you would have two clipboards each accessed with two different shortcuts.

Have you ever tried an advanced text editor such as GNU Emacs [1]? GNU Emacs provides a feature that I believe could fulfill your use case. In Emacs, rather than a mere 'clipboard' that holds the most recent thing you copied, you have the 'kill ring'. Anything ever copied to the 'kill ring' can be recalled at any time. You can copy as many things as you want and paste as many times as you want.

I don't use a Mac, so for me the shortcut in Emacs is Ctrl-k to 'kill' text (copy to 'kill ring') and Ctrl-y to 'yank' text back from the 'kill ring'. You can then use Alt-y to cycle through every piece of text that you have 'killed' in your current session. There are further shortcuts to select and copy text to the kill ring. (By default Ctrl-k removes all text on the current line or it removes the current line if the line is blank). Repeated use of Ctrl-k without other commands will grab entire chunks of text that can be brought back with only one Ctrl-y.

Would something like that work for your use case?

Of course with an advanced editor (like GNU Emacs), you have the option to program as many additional shortcuts as you want.

<comment><AUTHOR> I will check this out, maybe I can set up some shortcuts. Thank you</comment></comment></comment></comment>


Discord Confirms Layoffs - <AUTHOR> https://www.gamesindustry.biz/articles/2019-10-03-discord-confirms-layoffs <comment><USER2> The sooner Discord dies, the better off gamers will be.

<comment><USER3> Why do you say that? On the whole Discord has been a super useful tool for gamers and the industry. Curious what your experience has been.

<comment><USER2> Right, because reinventing IRC, pretending it's a revolutionary new product, and collecting user data to sell is actually good for gamers? If I wanted to monetize ignorance there are more honest ways to go about it.</comment></comment></comment>


Show HN: PastBook Moments – Beautiful photo books, with friends – in a snap - <AUTHOR> http://moments.pastbook.com/create?utm_source=hn

<comment><AUTHOR> We want to be "More than just printed books", allowing people to collect photos from relatives and friends in a private place, being able to turn them in a keepsake printed book within 1 click.

We've just updated the UI and added a new look&feel for the book template (code name 'magic-blur'). You can hand-pick photos for many social-network (we'll facilitate the import of multiple photos with a wizard within the next few iterations).

Any feedback is welcome. I'm the founder, you can reach out directly to me at stefano at pastbook dot com

Thanks</comment>


Lyft Crashes Below IPO Price - <AUTHOR> https://www.koyfin.com/charts/gip/LYFT <comment><USER2> "Volatile hype stock has volatile hype stock-like trading activity during a classically volatile trading period."

<comment><USER3> Thanks for the appropriate TL;DR

</comment></comment><comment><USER4> This mostly just means that Lyft did a good job in pricing their IPO to get the most money they could from it.

<comment><USER5> "Lyft rises after IPO" This means they did a good job! "Lyft falls after IPO" This means they did a good job!

I'm getting a destinct "this is good for bitcoin" feel about how people react to post IPO movements.

So going on from here, if they are above IPO is that good, or is it good if they are below IPO?

<comment><USER6> The banking syndicate takes on some risk in order to facilitate trading in a successful IPO. Usually to compensate for this risk the IPO price is (slightly) less than what they believe the stock will trade at. This way the IPO investors and the banks can make a bit of money for bearing this risk.

It's usually seen as unsuccessful and a bad-news story when a stock falls below its IPO price. Even though Lyft might have taken the max from investors, it will diminish its ability to raise further equity and its bankers will lose the trust of the IPO investors.

<comment><USER7> > it will diminish its ability to raise further equity and its bankers will > lose the trust of the IPO investors

... and since Lyft is far from being cash-flow positive, it wouldn't surprise me much if they were looking for new money in 1 to 2 years.

So if this turns out to not just be the market being volatile, but a serious trend, this can hurt them quite a bit.

</comment></comment></comment></comment><comment><USER8> Honestly between $UBER and $LYFT I have no idea why you'd own $LYFT.

$LYFT has all their eggs in one basket. It's a pure bet on US rideshare, which has been plateauing for quite some time.

$UBER has a global presence, and although lost in Asia owns a substantial share of Didi (#1 in China) and Grab (#1 in South East Asia), and now bought Careem (#1 in Middle East), and is still dominant in South America. It also has Uber Eats, which has grown to a multi-billion co on it's own.

It's also much further along on proprietary self-driving tech than Lyft is.

<comment><USER9> Uber (btw: did the all-caps and dollar sign add to the readability of your post?) is also much more expensive than Lyft is. At some point, you have to decide how much more you want to pay for a company to chase down inherently less-lucrative markets.

I think that Uber's self-driving technology is worth negative dollars.

<comment><USER10> > did the all-caps and dollar sign add to the readability of your post?

This is a standard way to denote stock symbols.

<comment><USER11> Uber doesn't have one though, seeing as how they aren't publicly listed

</comment></comment></comment></comment><comment><USER12> It's absolutely a normal behavior for a stock to go down post IPOs. Can be so many things, from people selling stocks they had for a long time, people who just speculated on the opening and are cashing in, or just because today it's cold and I had fish last night and I'm not feeling well and yeah just short that Lyft stock.

Let's see how it does in the next months.

<comment><USER13> Well, the financials look shady to me: $900 loss and no plan in sight. Perhaps the IPO euphoria was that short-lived?

Regarding the post-ipo crash - yeah, FB did that. Yet they turned a good profit soon after and then rebounded.

</comment></comment><comment><USER14> "Crashes" from IPO of $72 to $70.60 at the time of this writing. Okay.

<comment><USER8> Well it opened at $87 on Friday, so it's a 20% drop since opening.

<comment><USER15> It's still almost double the last private valuation. It was $10bn prior to IPO, now north of $20bn, peaking at almost $25bn.

<comment><USER8> For now...I mean it's been 2 days. Let's see after the first earnings report.

Remember employees are still in a lock-up period, so really no one who is holding right now really cares until 6 months from now.

</comment></comment></comment></comment><comment><USER16> I think "crashes" is a little bit sensationalist. They're down which is obviously not great but they're down by less than 10% at my time of writing. While it won't get as many upvotes this should probably be titled "Lyft IPO Poorly Received" or more literally, "Lyft Down 10% After IPO"*

Edit: This is actually their second business day.

</comment><comment><USER17> Good for them for taking all the money off the table. There's nothing dumber than an IPO that pops.

</comment><comment><USER18> IMO this means nothing. Facebook did the same thing.

<comment><USER19> Facebook was profitable or at least cashflow positive if I recall correctly.

<comment><USER20> And it still dropped more than 50% in the first year

</comment></comment></comment><comment><USER21> on IPO day, the IPO's bankers will buy up shares, "providing support" for the stock at a given price. it looked like management's preferred price point was $80 for most of the day, so the underwriters were buying at that price point. the greenshoe agreement helps the bankers buy at that point without actual economic exposure to the IPO (worth reading the wikipedia article if you're interested here). one explanation might be that the bankers bought up their entire allocation by the end of the day, which allowed price to drop to 78 in closing minutes.

after day 1, who cares, the bankers already got paid.

</comment><comment><USER22> Is today the first day you can short Lyft? Or could you do so on Friday already. I'm not sure of the mechanics of stock borrow right after an IPO.

<comment><USER23> As I understand it, you can short an IPO on day 1, but it probably won't work out very well for you, because the underwriting banks have agreed to buy shares at a specific price if the price falls. So if you try and short it you are getting into a game of 'who has more money' with a bunch of investment banks, which you will rarely win.

</comment></comment><comment><USER24> 'crashes' seems to be an overly dramatic and popular word this year, people who oppose the UK leaving the EU love to use it too...

</comment><comment> a-wu I thought a lot of tech stocks did this immediately after IPO as the pre-IPO shareholders sold off their shares?

<comment><USER17> That's not really common. Pre-IPO shareholders who are not locked up sell into the IPO, not right after it. That said, you aren't wrong about volatility right after an IPO. Look at ESTC: debuted at $70 and traded as low as $58 a few days later ... then as high was $100 recently.

</comment></comment><comment><USER25> Company which lights a billion dollars on fire each year is not a sound investment? No shit....

As a regular user of Lyft i still have 0% loyalty. I can get 3 or 4 different services in my city and you can be sure i'm picking the cheapest one every time. As soon as VCs stop subsiding my travel expenses ill move right on to the next service.

I'm guessing some of you are locked in for 6 months and my post made you sad =(

<comment><USER8> which city has 4 different rideshare companies in operation?

<comment><USER26> Austin at least 4... Uber, Lyft, Wingz, RideAustin

<comment><USER27> This is the reason I can't figure out how Uber or Lyft is worth billions of dollars. It doesn't seem like the barriers to entry are very significant. How long before there's an app that queries the different services and hails a ride from the service that can get there the fastest or provide the cheapest ride?

<comment><USER28> There's nothing stopping you from writing a Facebook clone. But it won't succeed. Why not?

<comment><USER29> Except ride-sharing doesn't have a network effect. I don't care if all my friends use Uber; it makes no difference and we all will use the next company if they're even a dollar less / ride and the service quality is on par.

<comment><USER30> Drivers care that lots of people use Uber and you care that lots of drivers use Uber. So there's definitely a network effect. It's just a lot weaker than something like Facebook because I don't care how many Uber drivers there are in Memphis if I'm in Salt Lake City. It's even weaker than that because the geographic area is more like "within 10 minutes of me". You can see a competitor relatively easily getting a toe hold by starting service at a specific time for a specific area. For example, the popular bar street on Friday/Saturday nights.

The problem comes with your "a dollar less" caveat. You star EpicEng's ride share and undercut Uber/Lyft by a dollar. They respond by matching your price and giving drivers more incentives so they don't switch. Now what do you do?

<comment><USER29> I can assure you that I do not personally care that people use Uber, but that's neither here nor there. What you describe is not a network effect; it's true of _any_ business you want to see stay in business. If I liked shopping at e.g. Walmart, yes, I would implicitely want others to shop there as I don't want to see them go out of business. That doesn't mean I'd have a second thought about switching to a competitor if they provided a similar service at a lower price.

FB is successful because no one I interact with is on a different platform. They same is true for them, so we all stay. Network effect.</comment></comment></comment></comment></comment></comment></comment></comment>


Signs of Secret Phone Surveillance Across London - <AUTHOR> https://news.vice.com/article/vice-news-investigation-finds-signs-of-secret-phone-surveillance-across-london <comment><USER2> Interestingly enough, during last trip to London, my phone (Nexus 5 running Cyanogenmod 12.1) was able to somehow detect _something_ fishy and warned me several times "Network may be monitored by an unknown 3rd party". Among others, I've seen this warning two times out of two when passing by Cheapside/St Martin's corner - next to the St Paul's Cathedral.

At the time I just dismissed this as some tinfoil hat developer adding some nonsensical warnings to the firmware, but in retrospect, after reading this article - this matches perfectly, chances are - phone was indeed detecting Stingrays. Still no idea how it managed to do it.

EDIT: I had no data/IP connection of any kind at and around the time of seeing this, so this is clearly unrelated to TLS interception.

<comment><USER3> I'm not getting these warning on my Nexus 4 running the default Android build. The only time I see them is when I use my own VPN connection.

Do you think it might get triggered on your phone by the presence of the anti- porn filter that UK mobile provider have? For instance, when trying to access "adult" website (I use quotes as sometimes, even non porno website gets filtered out) you end up on your mobile provider page blocking you from the actual website your looking for.

<comment><USER4> Some details regarding the message here: [http://security.stackexchange.com/questions/61750/android- ki...](http://security.stackexchange.com/questions/61750/android-kitkat- reports-network-may-be-monitored-by-an-unknown-third-party-whe)

<comment><USER2> This is not the message I've seen. There was nothing about TLS, trusted CA installation, emails, apps, or websites.

I wish I've taken a screenshot of it!

<comment><USER4> The message you quoted appears in the left-hand screenshot [1] showing notifications, not the one on the right containing a dialog box.

[1] [http://i.stack.imgur.com/7nCMFm.png](http://i.stack.imgur.com/7nCMFm.png)

</comment></comment></comment></comment></comment><comment><USER5> > A VICE News investigation has found evidence that sophisticated surveillance > equipment that spies on people's phones is being used across London

That the Met (and other police forces) regularly use IMSI catchers is not new information - here's a ~5 year old Guardian article on the subject:

[http://www.theguardian.com/uk/2011/oct/30/metropolitan- polic...](http://www.theguardian.com/uk/2011/oct/30/metropolitan-police- mobile-phone-surveillance)

</comment><comment><USER6> Watched the documentary last night.

Given that these things are cheap, would any fellow Brits be interested in clubbing together and acquiring one and installing it in or around parliament? I'm sure there would be plenty of buyers for the call records of MPS.

<comment><USER7> Isn't it illegal to have one and run one in the UK if not licensed?

<comment><USER6> Well, as they're officially not used at all in the UK, there's been no need to create any legislation around them, so while this could be an offence under the communications act, you could argue (probably unsuccessfully) that you're actually providing a service to customers by taking their data to protect them from themselves, as they may be terrorists and not yet know it.

<comment><USER8> It's almost certainly an offence under RIPA.

<comment><USER9> Most things are.

</comment></comment></comment></comment></comment><comment><USER10> Same thing found in Oslo about a year ago. Police Security Service denied they existed though. If I remember correctly these were mostly located around parliament and other government institutions as well as in the embassy area.

Report in english: [http://www.aftenposten.no/nyheter/iriks/New-report-Clear- sig...](http://www.aftenposten.no/nyheter/iriks/New-report-Clear-signs-of- mobile-surveillance-in-Oslo_-despite-denial-from-Police-Security- Service-8071885.html)

<comment><USER11> Hopefully there will be some action on this in Norway. Unless they want to ignore unconstitutional police and agency activity, just like in .. so many other major countries.

<comment><USER12> It took 40+ years of illegal surveillance of left-wing politicians before they finally took the allegations seriously and investigated it, and the result of extensive evidence of breaking the law was renaming the agency and some slaps on the wrist, so I have no reason to believe they've improved.

</comment></comment></comment><comment><USER13> Do IMSI catchers have any way of verifying the intercepted IMSIs are legitimate? If not, would it be possible to build a device to flood them with fake/spoofed IMSIs?

<comment><USER14> >If not, would it be possible to build a device to flood them with fake/spoofed IMSIs?

Technical ability wise, yes.

Legally, no. The Mobile Telephones (Re-Programming) Act 2002 [0] makes spoofing IMSI, even that of your own, illegal in the UK.

[0] [https://www.staffordshire.police.uk/info_advice/crime_preven...](https://www.staffordshire.police.uk/info_advice/crime_prevention/immobilise/reprogramming/)

Disclaimer: I am not a lawyer.

<comment><USER15> I fail to see how re-programming is related to spoofing?

<comment><USER16> > (1) A person commits an offence if:

> he changes a unique device identifier,

<comment><USER17> Technically, IMSI is not a device identifier. MT has IMEI and SIM (or more precisely ICC) has ICCID (which is normally never transmitted over the network). And the legislation probably specifically targets spoofing the IMEI, as spoofing IMSI does not gain you anything other than absence of service (on normal GSM/3GPP network).

<comment><USER16> The fact the Government is using it as an identifier likely means they can argue legally you are attempting to change the identifier.

Technically correct for technical discussions is not the same as contextually correct in a court room.

<comment><USER18> IMSI is not a mobile phone identifier, it literally means International _Mobile Subscriber Identity_ and is provisioned in the SIM card.

You will change your IMSI by simply changing the SIM card.

<comment><USER19> No you won't, IMSI provisioning is mostly done today remotely. The SIM card will have an empty IMSI partition and once you've "activate" it with the parent network the network will provision an IMSI on that card. If you have an account with a cell provider you'll carry the same IMSI number when you switch devices and SIM cards.

If you use pre-paid sim cards then those usually have thin provisioning of IMSI numbers they network buys a certain amount and activates them when the SIM card is activated and deactivates them once the SIM card has been inactive or not been topped off for a certain period of time (usually around 90 days).

When some one has your IMSI they can tie it directly to your personal details, phone number and various other details if they have sufficient access to the global cell system they can also get your location and what tower you are connected to. Historical log data will give them any tower you've been connected too from the first tower during the initial activation and provisioning to the last tower you've been connected too. Depending on the network and device most phones also send out nice diagnostic information about other towers and networks they see all the time regardless of what tower they are connected too at the time that with a given IMSI number will allow some one to triangulate the position of the device to under 10M in most urban areas if some one knows your IMSI they can pretty much pin point what room you are in at your house (give your house have several rooms pointing at different directions ;)).

</comment></comment></comment></comment></comment></comment></comment></comment><comment><USER20> Recommended app for phones not doing this by default:

[https://f-droid.org/repository/browse/?fdfilter=SnoopSnitch&...](https://f-droid.org/repository/browse/?fdfilter=SnoopSnitch&fdid=de.srlabs.snoopsnitch)

<comment><USER21> also [https://f-droid.org/repository/browse/?fdfilter=imsi&fdid=co...](https://f-droid.org/repository/browse/?fdfilter=imsi&fdid=com.SecUpwN.AIMSICD)

(does not need root)

<comment><USER22> and also does not detect anything. It's placebo.

</comment></comment></comment><comment><USER23> Richard from Privacy International pointed me at these: [http://www.amazon.co.uk/dp/B00RRL4XLW](http://www.amazon.co.uk/dp/B00RRL4XLW) It's a faraday cage for you phone. Pop it in and you disappear instantly.

<comment><USER24> I'd have thought simply switching the phone off would be easier? Much better on your battery life too, if the phone turns the transmit power up to try and reach a base station.

<comment><USER25> I wouldn't feel safe until the battery is removed (which unfortunately isn't possible on most phones anymore)

The baseband still has access to your battery when your phone is off.

<comment><USER26> > The baseband still has access to your battery when your phone is off.

Citation needed?

Because the definition of off, for most phones, is exactly that.

<comment><USER27> This capability has been known for many years. From 2006:

>"The FBI can access cell phones and modify them remotely without ever having to physically handle them," James Atkinson, a counterintelligence security consultant, told ABC News. "Any recently manufactured cell phone has a built- in tracking device, which can allow eavesdroppers to pinpoint someone's location to within just a few feet," he added.

Source: [http://blogs.abcnews.com/theblotter/2006/12/can_you_hear_me....](http://blogs.abcnews.com/theblotter/2006/12/can_you_hear_me.html)

I believe (but cannot cite) that this capability became mainstream when E911 & GPS was mandated.

This stuff is a big reason why BlackBerry was so critical to regulated industries and public company execs. PIN messaging on legacy BlackBerry was secure between devices on the same BES, and there wasn't a direct linkage to the user's identity, which made it easy to lower the value of metadata collection.

The fact that BlackBerry designed around this early on leads me to suspect (as an outside observer with an imagination) that mass metadata collection was known by folks in industry back in the 90s.

<comment><USER28> > The fact that BlackBerry designed around this early on leads me to suspect > (as an outside observer with an imagination) that mass metadata collection > was known by folks in industry back in the 90s.

Wouldn't a simpler explanation be that it was just over-designed for 90s-era threats in a way that hardened it to some more recent threats?

<comment><USER27> It is definitely a simpler explanation.

Consider however that none of their US based competitors managed to do address those threats in a meaningful way.

</comment></comment></comment></comment></comment></comment></comment><comment><USER29> I stayed in The City during the holidays and at one point walked close by the Police hq. After continuing on I enabled gps for a moment and even though I was half a mile a way my gps was showing me smack dab in the center of the police hq for about 15 minutes... I realized then what was happening and that I should have known better, but I had forgotten to ask a friend to take his faraday cage laptop bag and phone bag... I knew better and am still kicking myself for it.

The UK's level of surveillance is extremely unsetteling to me, and quite frankly I think a lot of Americans have forgotten all the reasons why the UK might not be as good of an ally as everyone thinks since the 47 USUK agreement. Thr point being that I really hope our politicians dont start adopting That level of surveillance just because they do it to.

It seems we have quietly been in a surveillance arms race, which isnt good for the population at all.

<comment><USER12> City is "special". While there are reasons to be concerned about surveillance elsewhere in the UK too, City has its own police force, and surveillance levels that makes even the rest of London seem like total anarchy.

In the rest of London there are certainly other buildings that are covered by extensive government surveillance, but most of the surveillance in London - and the rest of the UK - is privately owned, and rarely more than passively recording. The level of street level monitoring in the UK is often vastly exaggerated - police often can't be bothered even trying to check CCTV because getting hold of footage is a lot of effort and rarely is of much help.

GCHQ surveillance of networks is another matter.

<comment><USER30> It's not clear if the OP meant the City of London police HQ (Wood Street), or the Met HQ (Scotland Yard, not in the City)

</comment></comment></comment><comment><USER25> It doesn't really comes as a surprise, but it's good to see the news coming out. Now we need a legal framework to ensure this form of power isn't abused.

<comment><USER31> We the west, or America?

<comment><USER25> We humans?

edit: aside from that utopic reply, what I mean is "any country that has cellphones and want to protect their citizen should implement a legal framework to prevent abuse"

</comment></comment></comment><comment><USER32> When you combine this news with this one it makes you think twice before bringing your phone to a protest [https://news.ycombinator.com/item?id=10905643](https://news.ycombinator.com/item?id=10905643)

</comment><comment><USER7> I seem to recall a recent discussion where these devices are very hard to identify compared to a number of legit mobile phone amplification devises that many large buildings have for their employees in cities.

Is this the same technology?

</comment><comment><USER33> Are prices so high in order to prevent private use or are they really that expensive? What keeps anyone from building their own?

</comment><comment><USER34> I've read in the past that phone tapping produces an audible echo, is this the case with imsi-catchers as well or has the technology advanced far enough it's not possible to detect being tapped?

</comment><comment><USER35> If a technology exists, and can feasibly be leveraged by a party to its advantage, then you should assume that it is happening.</comment>


The Kafka Papers - <AUTHOR> https://www.weeklystandard.com/christoph-irmscher/review-of-kafkas-last-trial-the-kafka-papers <comment><USER2> This article misses so much of the point. Older, but much better: [https://www.lrb.co.uk/v33/n05/judith-butler/who-owns- kafka](https://www.lrb.co.uk/v33/n05/judith-butler/who-owns-kafka)

<comment><USER3> Discussed recently here: [https://news.ycombinator.com/item?id=17507556](https://news.ycombinator.com/item?id=17507556)

</comment></comment><comment><USER4> Oh I thought this was about the pub/sub platform. Guess I was wrong.

</comment><comment><USER5> Heh, I thought it was about the modern Kafka. For the disappointed: [http://notes.stephenholiday.com/Kafka.pdf](http://notes.stephenholiday.com/Kafka.pdf)

<comment><USER6> May be modern Kafka people should put other Kafka on the trial for using its name.</comment></comment>


Google to cut China porn results - <AUTHOR> http://news.bbc.co.uk/2/hi/technology/8112549.stm

<comment><USER2> With a huge population of angry men who can't get wives, this is a really dumb move from the view point of helping preserve the power of China's ruling party. They have enough riots and discontent as it is.

</comment><comment><USER3> > The news comes as China tries to make sure all new PCs sold in the country > are fitted with filtering software.

Scary. I wonder if it's (1) actually mandatory to use the software, (2) just a requirement for OEMs to make the software available or (3) optional, but on by default so most will end up using it.

<comment><USER4> Next paragraph in the article

"A popular outcry over the PC filtering plan prompted the Chinese government to clarify that, although the surveillance software will ship with every computer, it does not have to be used."

So I guess it will be 3.

</comment></comment><comment><USER5> If Google can do this for China, how come it cannot do it it for my "safe search" image results when I am at work.</comment>


Where Did Colleges Go Wrong? - <AUTHOR> https://www.psychologytoday.com/blog/nation-wimps/201510/where-did-colleges-go-wrong <comment><USER2> I just graduated college and what seems to be the problem among my peers wasn't that they were coddled too much but that they were facing the prospect of spending years of their life and tens of thousands of dollars and still not getting a job. If hard work guaranteed a job after college there wouldn't be this wave of anxiety. I know some people who worked super hard on college but still don't have a job after they graduate and if the older generations had to meet strict metrics or be unemployed they would've been stressed, too.</comment>


It All Changes When the Founder Drives a Porsche - <AUTHOR> https://medium.com/@micah/it-all-changes-when-the-founder-drives-a-porsche-32ac25c713ad?utm_campaign=Mattermark+Daily&utm_source=hs_email&utm_medium=email&utm_content=25419206&_hsenc=p2ANqtz--5KQWfGFmBxSZtzoY2EM6qXs54IFj0p-C7AHsCYSDZseYZ3AEQL8Bx8TSuKmikUT2UEBhIiPhr_ohp07MkvnuXxG2tYw&_hsmi=25419206#.xr6bsi9bn <comment><USER2> If I took a multi-million dollar payout, a Porsche would not be my first choice - understandable if Porsche is being used to signify a frivolous purchase, but there are much more expensive / flashy / prestigious cars out there to blow money on (any new Ferrari or Lamborghini will do)

... says the systems administrator that intends to lease a Porsche Macan at the end of the year when my current lease runs out.

<comment><AUTHOR> > understandable if Porsche is being used to signify a frivolous purchase

Yep, I think that's it. It's being used as a barometer. If the founder can afford a Porsche...

</comment></comment><comment><USER3> It is a very good article. Smart VCs should understand the difference between keeping founders lean and energetic and making them starving and distracted from their mission.</comment>


Ask HN: Make a New Year's resolution - <AUTHOR>

As the holidays are upon us and we are closing out the year, it's a great time for self-reflection and making the decision to improve. What are your goals/resolutions for the new year?<p>Come back in a year and let us know if you succeeded. <comment><USER2> Be Happy!

      happy= "what makes me happy"
      Think(happy)
      Do(happy)
      Be(happy)
      Find(reasons to be happy)

</comment><comment><USER3> \- Top 100k pageviews/month average on my tech blog

\- Write first book

\- Write first webapp or mobile app

\- Create something for sale (eBook, tutorials, etc.) for passive income

\- Graduate from college

\- Spend more time with family and away from the computer

\- Something exciting and unexpected ... that's what makes life special, after all!

</comment><comment><USER4> 2010's not over yet! Don't wait until the next year to be productive, start NOW. You all have 5 days left.

</comment><comment><AUTHOR> 1) Finish the iPhone application I've been working on in my spare time within the next 3 months.

2) Find a full-time gig at a fun/energetic company designing and creating products I love.

3) Put on 20 lbs of muscle

</comment><comment><USER5> 1\. Get 10,000 subscribers for digest.io

2\. Get 10,000 queries / post per day on spotted.at

3\. Smile more, appreciate life and get a date or two. :-)

</comment><comment><USER6> Get personally cashflow-positive without a job with iOS or webdev contracting and/or my new top-secret analytics project, hehe :)

</comment><comment><USER7> We've recently gotten our first paying customer after many free trials. Our goal is to get 100 customers within the next year.

</comment><comment><USER8> Mine is to quit drinking redbull.

<comment><USER9> Just don't switch to No-Carb Rockstar. One of these cans has 250mg of caffeine and I'm up to 2 per day. That's half a gram, which makes me feel like a true drug addict. I feel like Jessie from Saved By the Bell singing "I'm So Excited" all hopped up on caffeine pills.</comment></comment>