Arnold Schoenberg: Beauty and horror - <AUTHOR> https://www.the-tls.co.uk/articles/arnold-schoenberg-beauty-horror-grace-notes/ <comment><USER2> I spent several years studying and playing the piano works of Schoenberg. I loved it, so much so that I got the barcode from a CD of his piano concerto tattooed on myself (Emanual Ax was the pianist).

I remember thinking early on, how can anybody possibly memorize this? But the more I listened to it, the more the "melodies" stuck, and this was a break through for me. There is beauty in his music, and the more time spent with it, the more it really shines. Still to this day I can hum along to Op. 25 (the Suite for piano) -- something I never thought possible upon first listening.

I believe this is what distinguishes Schoenberg from later "atonal" composers.

As a pianist, my recommendations for approachable Schoenberg are the Piano Concerto (the first movement is a waltz!), Op 19, and Op 25, the two latter works being digestible in small pieces. Op. 33 is magical, and Op 11 is just plain difficult.

</comment><comment><USER3> Schoenberg's music is admittedly hard to get into. But it is well worth spending some time with it because there is nothing quite like it.

For a bit of context, Schoenberg's atonal style was the culmination of centuries of development of Western harmony. From the Baroque/Classical era onward, the direction of Western music was towards greater chromaticism extending harmonies further and further away from the simple major and minor chords. Some composers came very close to complete atonality, particularly Scriabin and Stravinsky, but Schoenberg was the first to dive into completely atonal music.

While it may sound like someone randomly plonking on the keyboard, he had to work quite hard to get the atonal sound he wanted since harmonies are so ingrained in the way we hear music (especially for composers!). He developed the "twelve-tone system" in which each note had to be played exactly once in a theme so as to guarantee that no tonality was accidentally introduced by stressing particular notes.

The result is a style that is very cerebral, but enjoyable once you let go of the idea that music should contain traditional harmonies. Personally, I think the music world got a little obsessed about the idea and continued to develop it for maybe four decades longer than it should have. (His twelve tone technique was later extended to "serialism" which generalized the process to rhythms, dynamics, and instruments, and wasn't really abandoned by "serious" composers until maybe the 1980s.)

Incidentally, Schoenberg may have scared himself to death. He was intensely superstitious, particularly of the number 13. When he was 76 he was contacted by an astrologer who told him that this was a dangerous year since the digits of his age added up to 13. Later in the year, on Friday, July 13th, he spent the day extraordinarily anxious and died shortly before midnight.

<comment><USER4> > Some composers came very close to complete atonality, particularly Scriabin > and Stravinsky, but Schoenberg was the first to dive into completely atonal > music.

Atonality can already be found in some late piano pieces of Liszt, e.g. "Nuages gris", which is largely based on augmented triads ([https://www.youtube.com/watch?v=tYKl41e_hoU](https://www.youtube.com/watch?v=tYKl41e_hoU)).

Before that, the music of Wagner already shook the foundations of Western tonality with its excessive chromatisism where any notion of a tonal center is often lost. Schönberg just continued where others have left and went to the extreme. It is also worth pointing out that he first composed in the so called "free atonal" style and only then, after a long hiatus, he developed his twelve-tone-system. By the way, there have been other people who developed similar systems around the same time, notably Josef Matthias Hauer.

Fun fact: Stranvinsky turned towards twelve-tone-technique in the fifties.

<comment><USER5> You can find a tone row in Bach even. Whether or not he consciously aimed to construct one is a debate that has no end, but it's interesting to challenge the conception that old = more traditional/harmonic, when in fact music history is much more wobbly than that.

<comment><USER6> The original chromatic series is in Lasso in the very late 16th century - Carmina Chromatico from Prophetiae Sybillarum.

It's decorated with smooth triads and moments that sound like cadences, but the progression as a whole is completely atonal.

[https://www.youtube.com/watch?v=al41WvDW- OA](https://www.youtube.com/watch?v=al41WvDW-OA)

</comment></comment></comment></comment><comment><USER7> As a music student, I was always amazed at the irony of Schoenberg's thesis about the "Liberation of the Dissonance", when 12 tone Equal Temperament is an arbitrary intonation system that limits the actual potential for freedom when creating harmony.

Ben Johnston, an American composer who studied with Harry Partch, used extended Just Intonation, which is a system of unlimited harmonic capabilities, for several serialist pieces [1][2]. I feel like he was able to achieve striking dissonance unlike anything capable within the confines of Equal Temperament.

[1] [https://www.youtube.com/watch?v=9ujeXlFP7p0](https://www.youtube.com/watch?v=9ujeXlFP7p0)

[2] [https://www.youtube.com/watch?v=E5HIPRuYdjA&list=OLAK5uy_mn3...](https://www.youtube.com/watch?v=E5HIPRuYdjA&list=OLAK5uy_mn3eBJYDso4Hth49IZySEWnEv2itGSYmE&index=7&t=0s)

<comment><USER8> Schoenberg gave the scale some decent discussion in his Harmonielehre in the section on the major mode and diatonic chords. Overall, he was liberal and encouraging about the directions that music could go, and he led by example in producing his own compositions in his own way.

"And above all; this scale is not the last word, the ultimate goal of music, but rather a provisional stopping place. ... Whether there will then be quarter tones, eighth, third, or (as Busoni thinks) sixth tones, or whether we will move directly to a 53-tone scale that Dr. Robert Neumann has calculated, we cannot foretell. Perhaps this new division of the octave will even be untempered and will not have much left over in common with our scale. ... Probably, whenever the ear and imagination have matured enough for such music, the scale and the instruments will all at once be available."

I'd say that last prediction was very prescient!

<comment><USER7> Great quote, thanks for sharing! Maybe I have misplaced my frustration on Schoenberg, when he doesn't deserve it. The hordes of academic composers who came after him and pumped out soulless 12-tone serialist pieces probably do deserve the scorn, though. :)

</comment></comment></comment><comment><USER9> I would recommend to anyone who has some basic musical education (like can play tunes or improvise a little on the piano/guitar) to try playing with tone rows. It's a brain expander on its own -- the discipline of tone rows makes evident the obscure role that tonality or even common chord progressions play even in something by e.g. Eric Dolphy or Sonic Youth (different brands of "experimental music")

</comment><comment><USER10> I'd like to speak in support of Schoenberg's (only) piano concerto as a genuinely enjoyable piece of music to listen to.

Although strictly atonal using a tone-row method, it uses quite traditional phrasings that are fairly easy to latch on to mentally, resulting in something quite sympathetic, _almost_ hummable, only one step ahead of your mind, and it's a light step. Nothing portentous or self-regarding about it.

There's an excellent recording of it played by Mitsuko Uchida, with Boulez conducting the Cleveland orchestra.

</comment><comment><USER11> This music will destroy you. He barely survived it himself.

Very skilled though... Hit it a time or two on YouTube, then move on. Don't linger!

<comment><USER12> That sounds like a challenge. Are there any particular pieces you would recommend I don't spend too long on?

<comment><USER11> The early works alone were enough to gain him a loyal and devoted gang of students.

Start at opus 1, no encore. Terrible philosophy--like cyanide in a candy shell.

</comment></comment></comment><comment><USER13> For those who don't know who Schoenberg is: he's a composer of "abstract" music. Think of a musical equivalent to the abstract art. [https://youtu.be/2V-qmC6xUW8](https://youtu.be/2V-qmC6xUW8)

<comment><USER4> It is worth noting that Wassily Kandinsky reached out to Schönberg because he saw parallels in Schönberg's music to his own abstract art. But I think this parallel only exists in terms of breaking with the conventions and traditions of the medium, i.e. mimesis in visual arts and tonality in (Western) music. One could argue that music is always "abstract" in the sense that there is no real model in nature which it can abstract from. After all, music is always artificial.

<comment><USER13> _music is always "abstract"_

To me, the difference between the atonal or serial music and traditional classical music is in the amount of structure or order (that I can recognize and process). Bach's or Chopin's music has a lot more of it than Schönberg's. Also, classical music feels "natural", and is pleasant to listen to (for the most part), while atonal music feels "artificial" or "weird", and for the most part is not pleasant.</comment></comment></comment>


Hetzner Private Cloud - <AUTHOR> https://www.hetzner.de/us/hosting/produkte_vserver/private-cloud <comment><USER2> We have a lot of experience with Hetzner servers and I used and recommend this hoster since at least 10 years intensively with tens and hundreds of servers.

The most important thing with Hetzner Servers is to monitor everything very closely:

\- CPU Temperature

\- RAM

\- Disks (SMART)

\- Software- and Hardware raids

\- Network (interface) errors

The servers are usually consumer-grade hardware components which have more often issues under heavy load so you have to expect down-times and broken components. However, if you are aware of that and you can easily shift around that with your software Hetzner will save you serious money (10 to 15 times cheaper than GCP and AWS). Also to mention is that their customer support is first class if you tell them all required details and exactly what to do. Usually they respond in minutes and do hardware replacements within an hour and small downtimes.

<comment><AUTHOR> What do you think of their more 'server-like' offerings like the PX61 line [0]? What do I have to expect in terms of downtime and component replacements?

[0] [https://www.hetzner.de/de/hosting/produkte_rootserver/px61nv...](https://www.hetzner.de/de/hosting/produkte_rootserver/px61nvme)

<comment><USER3> Those are actually (I think Fujitsu) Workstations. You should expect the same downtime you would expect from your own workstation if you were to use one at home. Maybe a bit less downtime since there would be less startups and the temperature differences would be smaller as well. Obviously, server grade hardware will perform and last longer under heavy loads.

I believe if you don't go with the Server auction thing, then you get quite new hardware. So I guess you would not really have to expect a lot of downtime. But as always, downtimes _can_ happen. Always plan accordingly.

<comment><USER2> Absolutely, the new servers are ok but after a while of permanent load (a year or so), you'll also have to expect issues, at least in our experience. The server auction itself is worse but they replace hardware without any issues and most often the replaced hardware is new as well.

</comment></comment></comment></comment><comment><USER4> I've also stumbled upon that. However the question remains, how to add more compute nodes? Is there a easy process to do that? How about updating it? Isn't it carless to actually say:

        You will have sole and unrestricted administration
        rights to the dedicated hardware with root access.
        Hetzner Online will not have access to the servers, and
        will therefore not be able to provide server
        administration support.

?

I mean if I can't provision it, it's probably problematic to update it.

<comment><USER5> You are right, it's not so much private cloud on bare metal as bulk metal you manage.

OTOH, if that's what you want (many enterprises think they do), this positioning and landing page puts Hetzner into consideration.

</comment></comment><comment><USER6> This isn't quite hitting the spot to me (non-server hardware, you still administer the OS, single location), but it does seem indicative of a potential new wave of low-cost cloud providers.

Someone like Vultr, Linode, or DO is positioned well to deliver an "AWS lite" offering. They all have decent hardware, lots of locations, and a good delivery history. A bit of work to put together ELB/EC2/Lambda/S3 equivalents and a control panel would open up a new market. Especially if they offered low egress pricing.

<comment><USER7> For me it's on spot, I don't like Amzn, goog, msft blackbox. This is a decent HA system for 90% startup adding just backup will make it perfect. It's better then ELB/EC2/Lambda/S3 as it uses openstack api under your own control. I am happy customer of hetzner for 4 years which is better given personal data privacy better in Germany then in USA(initially that was the primary reason of choosing them, to get away from usa based data center after Snowden).

<comment><USER6> I just don't see how it's any different than what they had yesterday. You can buy two cheap non-server-hardware servers and put openstack or coreos on them and administer it yourself.

All they did here was pre-install openstack, but leave you to keep it updated. If you can't install it yourself, good luck upgrading it when a security release comes out.

I mentioned ELB/EC2/Lambda/S3 equivalents for 2 reasons. First, AWS is clearly the market share leader, so having a similar pattern might get more buyers. Second, it's a bit easier pattern for apps that aren't cloud aware. But, they could just offer hosted K8S with some add-on ingress controllers.

<comment><USER8> I also don't get what this offers over renting these machines individually. It can't really be some preinstalled software with no support whatsoever as installing usually is the easy part.

<comment><USER9> Installing is easy, yes, but installing right can be tricky for many folks. There's a ton of conflicting info on best practices. Not detracting from your point, I agree it doesn't make sense, just saying installing right can be hard too.

</comment></comment></comment></comment></comment><comment><USER10> I have been happy with using Hetzner services in the past and I wish I had a business use for this. I used openstack for a while on IBM bluemix and found it convenient enough. I would like a good backup recovery setup. I hope that they configure the systems for some redundancy between the two servers, but it is not clear from the ordering page.

</comment><comment><USER11> It's totally unsupported. If you were not able to just rent the tin and configure this yourself then you're probably not going to be able to maintain it long term. This product is dangerous and some people will learn that too late.

<comment><AUTHOR> As far as I understood it the OpenStack software will be automatically updated on the releases of the LTS channel, so calling the product dangerous seems like an exaggeration to me.

<comment><USER12> Have you run openstack? There are million dollar companies out there that just support maintaining any updating openstack for a reason...

<comment><USER6> Their list of pieces and parts gives a good insight to how complicated the beast is: [https://www.openstack.org/software/project- navigator#tiles](https://www.openstack.org/software/project-navigator#tiles)

</comment></comment></comment></comment><comment><USER13> Desktop processor without ECC memory plus very slow SATA hard drives - not a setup for reliability and performance

<comment><USER7> I don't get it for 90% of startup this setup is more than enough to start and far cheaper then goog, Amazon, azure. Just the problem is most modern devops are lazy to learn the basics of setting a HA system with proper backup. Hertzner make it easy but one needs to know what they are doing. I am happy customer of hetzner for 4 years which is better given personal data privacy better in Germany then in USA(initially that was the primary reason of choosing them, to get away from usa based data center after Snowden).

<comment><USER14> So what, I save $100 over Google but spend 3h a week futzing with configs?

<comment><USER15> I've run the numbers with Hetzner, GCP, AWS, and even more managed products such as Firebase, Heroku, etc.

Bare Metal compared to GCP or AWS will save you about 75% of your operating costs.

Bare Metal compared to Heroku or Firebase will save you around 90% of your operating costs (a large part of this being caused by bandwidth, which is massively overpriced at Google and Amazon).

With those savings you can usually serve 5 to 10 times as many customers.

That might not be worth it if you're in SV, and pay your devs the same wages Amazon or Google do (as then you'll just pay more than with AWS or GCP), but if you're in places where you pay half the wages Amazon or Google do4 , you can actually save a lot with this arrangement.

<comment><AUTHOR> I am really reluctant on setting up my own server cluster on bare-metal right now, can you recommend some specific open-source tools to manage and monitor these clusters?

<comment><USER9> Kubernetes on CoreOS is a good option. Tectonic makes the setup part relatively easy.

<comment><AUTHOR> Ok, thanks a lot. Since we're on it, is there any open-source software available that is specifically targeted at easily setting up storage servers (maybe with an S3 like SDK)? I found myself pretty much forced to use GCS because of a lack of good alternatives.

<comment><USER9> I haven't used it personally, but Minio [0] is something I've heard mentioned more than once.

[0] [https://github.com/minio/minio/blob/master/README.md](https://github.com/minio/minio/blob/master/README.md)

<comment><USER15> Minio is very nice, but sadly it only allows one set of credentials – I'd have preferred being able to separate the access permissions of each service, but that's not supported.

</comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER16> I used Hetzner like 10 years ago and didn't had good experience. I doubt anything changed over time. They offer home grade hardware and low priority support in return of cheap prices. They only deal with hardware and network issues (which is quite normal for Dedi service with normal support option)

\- Hardware they offer is more prone to fail because of using home grade hardware for long time (especially HDD).

\- It's almost impossible to convince them HDD is failing even with showing SMART logs. Hardware needs to fail so they will replace it.

\- Hardware replacement times are quite fast (thanks to SLA). They replace it with another used HDD, if you want something newer, than they ask some money for replacing with less used HDD.

\- They scan their network regularly for hosted malware, trojan etc. so if one of your sites get hijacked and has iframe viruses etc. Hetzner will null route your server.

\- If your IP gets DDOS, null route.

\- If you get DMCA warning, null route without waiting 24 hours.

\- If your NAT leaks your internal traffic to WLAN, null route.

\- It takes almost few day to lift null route ban on your server when you get in contact with support. It's okay for support tickets to wait in queue for long time because of service level but I believe null route tickets needs priority no matter what.

We decided to move over to another provider after having problems.

Hetzner also owns few other brands like Serverloft.

<comment><USER17> Why would a German company do DMCA?

<comment><USER18> good question ...

another german hosting provider also required you to at least respond to dmca + three strikes

</comment></comment></comment><comment><USER19> OpenStack. Way overkill. I would advice always against OpenStack unless you have very good reasons to go into this direction.

</comment><comment><USER20> The company I'm working for moved away from hetzner coz it has a single location and far too many noisy neighbourhood. Hetzner was often target of DDoS and our connectivity was also affected.

</comment><comment><USER21> Here I was enthusiastic, but it's not-quite-there. If they took up administration of the Openstack setup this would be a very interesting product.

</comment><comment><USER22> the auction servers seem like better bang for the buck

<comment><USER8> Depends on what you want. It's used (for many years usually) Hardware which increases the probability of failure and you only get whatever single configuration is currently available. It's nice though that they offer you to cancel at no charge for 14 days and the variety of configurations available which are often more asymmetric compared to their usual offerings, e.g. if you primarily need a lot of disk space you don't have to pay for a lot of RAM and a fast CPU.

<comment><USER3> That doesn't sound like an issue though if you just need something cheap for now to just get going. You can keep in mind that it could fail any time and just plan around that (for now).

</comment></comment></comment><comment><USER23> Hetzner: Dedicated Root Servers AMD Ryzen : [https://www.hetzner.de/us/hosting/produktmatrix/rootserver-a...](https://www.hetzner.de/us/hosting/produktmatrix/rootserver- amd)

* AMD Ryzen 5 1600X

* AMD Ryzen 7 1700X

</comment><comment><USER24> But it is in germany - sort of police state in term of Internet. No thanks.

<comment><USER25> In Autumn 2017 there's going to be a new Hetzner datacenter in Finland [0].

[0] [https://www.hetzner.de/it/hosting/presse/info-0916](https://www.hetzner.de/it/hosting/presse/info-0916)

</comment></comment><comment><USER26> I used Hetzner services until I received an email from there about some of their servers being infected in the RAM.

Here is the email that I received in 2013:

Dear Client

At the end of last week, Hetzner technicians discovered a "backdoor" in one of our internal monitoring systems (Nagios).

An investigation was launched immediately and showed that the administration interface for dedicated root servers (Robot) had also been affected. Current findings would suggest that fragments of our client database had been copied externally.

As a result, we currently have to consider the client data stored in our Robot as compromised.

To our knowledge, the malicious program that we have discovered is as yet unknown and has never appeared before.

The malicious code used in the "backdoor" exclusively infects the RAM. First analysis suggests that the malicious code directly infiltrates running Apache and sshd processes. Here, the infection neither modifies the binaries of the service which has been compromised, nor does it restart the service which has been affected.

The standard techniques used for analysis such as the examination of checksum or tools such as "rkhunter" are therefore not able to track down the malicious code.

We have commissioned an external security company with a detailed analysis of the incident to support our in-house administrators. At this stage, analysis of the incident has not yet been completed.

The access passwords for your Robot client account are stored in our database as Hash (SHA256) with salt. As a precaution, we recommend that you change your client passwords in the Robot.

With credit cards, only the last three digits of the card number, the card type and the expiry date are saved in our systems. All other card data is saved solely by our payment service provider and referenced via a pseudo card number. Therefore, as far as we are aware, credit card data has not been compromised.

Hetzner technicians are permanently working on localising and preventing possible security vulnerabilities as well as ensuring that our systems and infrastructure are kept as safe as possible. Data security is a very high priority for us. To expedite clarification further, we have reported this incident to the data security authority concerned.

Furthermore, we are in contact with the Federal Criminal Police Office (BKA) in regard to this incident.

Naturally, we shall inform you of new developments immediately.

We very much regret this incident and thank you for your understanding and trust in us.

A special FAQs page has been set up at [http://wiki.hetzner.de/index.php/Security_Issue/en](http://wiki.hetzner.de/index.php/Security_Issue/en) to assist you with further enquiries.

Kind regards

Martin Hetzner

</comment><comment><USER27> This really needs a website that has a more modern feel to it. It doesn't exactly evoke trust.

<comment><USER6> Check out Berkshire Hathaway's website. [http://www.berkshirehathaway.com](http://www.berkshirehathaway.com)

<comment><USER27> You've really done a great job when the site explicitly has to state "Official Website"...</comment></comment></comment>


How Twitch Learned to Make Better Predictions About Everything (2017) - <AUTHOR> https://hbr.org/2017/05/how-our-company-learned-to-make-better-predictions-about-everything <comment><USER2> Having implemented several projects in the world of analyzing data to make predictions, I think a bigger issue exists: the philosophical (existential?) difference between frequentists and Bayesians. Essentially these two approaches have 'irreconcilable differences'. This is where the 'not enough evidence' objection (objection 3 in the article) usually rears its ugly head. In my observation, the reason silicon valley gets a deserved reputation for using data to make decisions well is that they are (mostly) Bayesian. Startups have to make decisions with very small data sets. If they were to wait until there was a large sample size of users, they would never get over the chicken- egg problem of scale. So they all out of necessity go talk to their small set of users, find out what they like, then make prior assumptions about what a slightly larger group of users might like.

<comment><USER3> Good scientists are conversational in both languages of probability, even if they are fluent and most-comfortable in one.

Both approaches have strengths and weaknesses; the application of the appropriate tool at an appropriate time tends to have the greatest success.

<comment><USER4> The parent isn't talking about paradigm/approach; they're talking about how a certain class of people ("statistics-users _in_ or _from_ academia", let's call them) tend to believe in things like the "statistical power" of an experiment, which—while only _sensible_ under frequentism—isn't really a frequentist idea, but rather just a peculiar tradition of academic rigour from before it was easier to multiply large numbers in meta-analyses.

Or, to put that another way: by "frequentism", the parent poster is referring to those people who believe that one thousand experiments on five people each add up to nothing, because none of them individually had enough power to draw a significant result. And by "Bayesianism", the parent poster is referring to those people who just do the five-person experiments and use whatever data they spit out, however noisy it is, because fractions of a bit of information are still more information than they had before.

</comment></comment></comment><comment><USER5> > We are actively trying to build a culture that promotes "psychological > safety," defined as "a sense of confidence that the team will not reject or > punish someone for speaking up."

Wow, everywhere I've ever worked has tried (consciously or unconsciously) and succeeded to build the exact opposite culture.

<comment><USER6> I've been so fortunate to work at two companies in a row where this "psychological safety" is ingrained deeply in the culture. It's something I care so deeply about as a person who saw themselves learning and growing _less_ directly as a result of _not_ having this "safety" inherent to the organization. I think it's useful in all areas of a company but especially important for engineers. I would much rather have a junior engineer hit a roadblock and throw up the white flag asking for help than for them to sit there for a full day stuck, banging their head, and feeling dumb. It's so easy to course-correct when you explain the culture up front: "We're all wrong all the time, if you get stuck or have a question, or someone says something that doesn't make sense, ask them. No one here is smarter or better than you just because they have the answers to questions you haven't even had a chance to ask before."

I would bail so quickly it would make my head spin if I had to work at a place where people are ever shot down for not knowing things and asking questions. The punchline is a lot of those people would tell you they're working on "the most interesting thing" and yet if you're working in a space where everyone is supposed to know all the answers... then there's nothing to learn. That doesn't sound very interesting to me.

<comment><USER7> I never worked at a place like that, but now I want to...

After over 15 years and a handful of jobs, from POS enterprise software to game porting, I started to think of psychological safety as a SciFi term :)

I'll keep looking for my holy grail.

<comment><USER6> Keep at it. They're out there. Rev (rev.com) was fantastic for this in engineering. I'm currently at the Predictive Index and we effectively have a "no dbags" rule in the culture. If you're not nice or you're not helpful, you're not going to last. It's something we're really focused on keeping as keep growing. It's a hard problem, maintaining culture as a company scales but I'm really hopeful at least that one facet stays around.

I wonder if it's something you can weed out companies for during interviews. I imagine you could iterate on some questions for the interviewer that, assuming they didn't lie, would give you a pretty good indication of this "safety" factor. Something like: "Can I go up and ask anyone a question about what they're doing?" It might rely on you speaking to real employees. I imagine if you're speaking to some very HR-y types, they might just be focused on saying "yes" to whatever question you have.

</comment></comment></comment></comment><comment><USER8> I once had am interview at an HFT firm that had a very long quiz. It was too long to finish completely and accurately in the time given (about twice as long - 45 minutes for about 20 questions plus 20 follow-ups), but you were given instructions to go as quickly as possible and finish as much as you can.

Every other question, a follow up to the substantive quotation, asked you to evaluate how sure you were in the previous answer.

So a question might be a little theory or short answer or maybe asked to write code to do a simple bloom filter. The next question asked how sure you were it had no bugs or would work if all values were 4 character strings.

Probably the second toughest interview I ever went on. But I found the idea fascinating. The idea was for the quiz to test your ability to work under pressure and be able to evaluate risks in your code.

<comment><USER9> That sounds horrible and fantastic at the same time.

But what was the toughest interview if that wasn't it?

<comment><USER8> Tie between a trading firm and a bulge-bracket bank. The trading firm was two days onsite. The first day was a lot of tough programming questions and the second day was tele-conferencing with other offices including regulatory and trading questions. (They did fly me out first-class and put me up in an amazing king suite at the Trump with full kitchen and living room).

The bank's questions were just brutally difficult. From low-level C++ and Java internals to algorithmic ones where you are at best hoping for a good approximation. And one very good series of questions on modeling a game where the answer involved using a stochastic matrix or monte carlo simulations.

<comment><USER10> I also interviewed at some bulge-brackets - hands down the most difficult interviews I ever had (for quant roles). They kept hammering on really complex math/stats/programming questions. Once you would get one "right", they would hit you with something more difficult. I have read that their premise was to see how you could handle pressure and questions you didn't know the answer to. In one follow up I was asked if I remembered a previous question and if I had looked it up.

</comment></comment></comment></comment><comment><USER11> I really enjoyed this article. Only after discovering Critical Chain project management did I discover the benefits of moving away from point estimates on software projects. Or just about any project where life, limb or financial ruin isn't at stake. I'm constantly asking people to estimate the probability associated with whatever commitment they're making. Not as in "Give me a number." but simply "Is it very likely, somewhat likely, not likely at all", etc.

I'm curious to know how they arrived at the 80% interval and whether that degree of certainty is optimal. One could argue that 50% would be a better choice if the goal is to improve one's ability to forecast.

<comment><USER12> In my first job out of college I was regularly asked not for point estimates, but for _time based LOE estimates_. As a junior engineer. My inability to do so honestly based on a lack of information was my first point of big, me- versus-management friction. Eventually we compromised to confidence intervals, which TBH I think provided more and better information and a few other developers eventually picked up using.

I wasn't going to commit myself to a hard number if it wasn't life-or-death stuff. The company (and no company since) was worth that.

</comment></comment><comment><USER13> Ray Dailio's new book Principles deals a lot with this sort of idea. He is a huge fan of creating formulas to assist with prediction. Also, writing down problems and your solution to that problem so that you can go back and see if your solution was effective, and if not, what went wrong and what you can change to get the desired result.

</comment><comment><USER14> The amount of bullshit hail mary percentage figures in this article were too much to get through, had to stop reading. If you simply think something will be more likely to succeed than not..then just say that..don't say 60% chance when your precision of prediction is a toggle between, fail, might be ok, might be mildly successful, or will probably succeed. When qualitatives become quantitative because of pedantic microscopy, there is a problem..

<comment><USER15> With practice, it's easy to make meaningful predictions down to that granularity. For example, Tetlock finds that with the superforecasters in GJP, their exact percentages are important enough that merely rounding to the nearest 5% or so makes their overall performance significantly worse. (This isn't so mysterious if you think of it in terms of frequencies: predicting a NK nuke test at 5% rather than 10% may seem specious at first, but surely there is a big difference subjectively between 'every 20 years' and 'every 10 years'?)

</comment></comment><comment><USER16> The company I work for (more or less B2B SaaS) does everything quick and dirty. Good gut feeling brought them far, but there is next to no data apart from total sales and some basic google analytics. Stuff like A-B testing is _far_ away.

Has anyone had a similar situation? How to handle that?

I'd love to do estimates and proof them right or wrong. But bundled feature releases, marketing and season all end up in the same number of "total sales this month". So far I did not manage to make them at least track churn/retention in a detailed way.

</comment><comment><USER17> Twitch's Glassdoor reviews noticeably started tanking since last year.

</comment><comment><USER18> Great article. Agile has some similar tactics that are worth preserving like the "cone of uncertainty".</comment>


Be Impatient - <AUTHOR> https://www.benkuhn.net/impatient/ <comment><USER2> Hmmm...

I would say this instead: Learning how to deal with your impatience is a way of learning how to deal with the fact that you are not in control of your universe -- a good skill to have. Impatience is symptomatic of stress and I think just about all of us could do with less stress.</comment>


Show HN: Keep Women in Tech (Over 40% quit tech mid-career) - <AUTHOR> http://keepwomen.com/ <comment><USER2> There is a high rate of burnout for men in tech too.

There certainly are real forms of bias and discrimination but "women's problems" AND "black problems" intersect with "people problems" \-- which is one reason why these problems are so intractable.

</comment><comment><USER3> 40% of women quit tech mid-career. That is a just a statement of fact (I presume). But is that a bad thing ? I mean, it is possible that there are several good reasons for the phenomenon.</comment>


Show HN: Build live location sharing in your app with HyperTrack - <AUTHOR> https://github.com/hypertrack/hypertrack-live-android <comment><USER2> I highly recommend also Open Sourcing the server, or else you'll have to compare against Open Source alternatives:

\- We did a prototype last July on saving 100M+ updates for $10/day all costs (cpu, disk, backup). Proof: [https://www.youtube.com/watch?v=x_WqBuEA7s8](https://www.youtube.com/watch?v=x_WqBuEA7s8)

\- You can 1 click deploy to a free Heroku server here: [https://github.com/amark/gun#heroku](https://github.com/amark/gun#heroku)

\- Watch a demo of the GPS tracking here: 1min [https://youtu.be/7ALHtbC9aOM](https://youtu.be/7ALHtbC9aOM)

\- Demo of the app here: (warning: asks for location) [http://gps.gunDB.io/](http://gps.gunDB.io/)

\- Source code here: (only ~200LOC, lots to improve) [https://github.com/gundb/gps](https://github.com/gundb/gps)

</comment><comment><USER3> Pricing looks way too expensive to me even for small to medium scale usage. And if my business cross the medium scale , then why wouldn't i really build it inhouse. Seem like a classic case of product looking for problem.

<comment><AUTHOR> We have several large scale businesses that are paid customers and find it cheaper to use us, than build it in-house. It's about the cost of an engineer, and that's a fraction of what they will incur, ongoing operating costs notwithstanding

<comment><USER3> Businesses for whom location tracking is critical process component and not a good to have such as logistic companies or lets say food/medicine delivery companies who also already have an app deployed with their end agents, the additional cost for them to get location tracking and reporting integrated in their mobile apps is trivial and also there is no technical moat as is there in lets say messaging or SMS APIs ( like Twilio). Either I don't understand your customer set, or problem you are solving is simply not big enough. You are trying to do to location tracking what twilio did to messaging, but reality is location tracking as a service doesn't make a very solid business case here. But best of luck :)

<comment><USER4> "... the additional cost for them to get location tracking and reporting integrated in their mobile apps is trivial..."

As a professional developer I would say that its not trivial, at least not cheap to develop. Theoretically all problems you know how to solve are trivial. Professionally you know that developing a solution that is flexible, reliable, supportable, extendible, user friendly and maintainable takes time, expertise and money to develop.

</comment></comment></comment></comment><comment><USER5> Didn't Google Maps do this already for free ? Why should I abandon those and use this ?

<comment><AUTHOR> Google Maps and other map APIs are great for visuals, routes and ETAs. Where they lack is generating a battery efficient accurate location stream and mapping that to your app's workflow. Plus, map APIs are priced on the basis of number of API calls or views, both of which can lead to unpredictable cost for such a feature. For a more detailed analysis, check out our blog post: [https://blog.hypertrack.com/2017/04/23/building-live- locatio...](https://blog.hypertrack.com/2017/04/23/building-live-location- features-requires-more-than-maps-apis/)

<comment><USER6> This is pretty cool - [https://blog.hypertrack.com/2017/04/18/pitfalls-using- locati...](https://blog.hypertrack.com/2017/04/18/pitfalls-using-location- streams-building-live-location-features/)

Is there something in the protocol that makes it more efficient?

<comment><AUTHOR> I'm guessing you're referring to MQTT. With smaller packet sizes it's more battery efficient than HTTP if you're making continuous network requests. Great comparison post here: [http://stephendnicholas.com/posts/power- profiling-mqtt-vs-ht...](http://stephendnicholas.com/posts/power-profiling- mqtt-vs-https)

</comment></comment></comment></comment><comment><USER7> How much of a battery drain is it to be constantly GPS tracking?

<comment><AUTHOR> <1% per hour. This is achieved by: 1\. use consumption patterns to know when to transmit data (eg, if no one is actively tracking, no need to transmit data on radio) [1] 2\. using accelerometer and gyroscope data to know when to collect data (eg, if you're not moving, no need to use GPS)

[1] We blogged about how we built out our variable frequency model: [https://blog.hypertrack.com/2016/11/28/battery-efficient- rea...](https://blog.hypertrack.com/2016/11/28/battery-efficient-real-time- gps-tracking/)

<comment><USER8> The blog post claims ~5% per hour.

<comment><AUTHOR> Ah, old post actually, dated Nov 2016. Just wanted to share it for the variable freq approach - sorry for the confusion! We released a major update of the SDK this March which brought in significant improvements due to sensor data.

</comment></comment></comment></comment><comment><USER9> Looks pretty cool! Do you have something for iOS as well?

<comment><USER10> It's in the works Parul! Should be out within a month

</comment></comment><comment><USER11> Is Hypertrack open source?

<comment><USER12> No, this is just a demonstration of how to use their API in an app.

According to the pricing[1] page, actual use is US$0.04 per "action" (which they describe as "deliveries, pickups, dropoffs, visits, appointments or anything you may decide")

[1] [https://www.hypertrack.com/pricing](https://www.hypertrack.com/pricing)

<comment><USER13> Maybe I don't understand it but that seems really expensive.

<comment><USER14> Show HN: How to use Michael Jackson samples in your music

Step 1. Download and install Audacity and LMMS

Step 2. Get clearance agreements from the Jackson estate

Step 3. ...

</comment></comment></comment></comment><comment><USER15> What value does this add which Glympse or PathShare already don't provide?

<comment><AUTHOR> APIs! HyperTrack is built to integrate into your existing product experience and workflows.

<comment><USER15> What do you mean by API?

Both Glympse and PathShare have fairly elaborate set of APIs on iOS and Android. Not sure I understand the distinction.

<comment><AUTHOR> My bad, I should have been clearer. Both Glympse and Pathshare are great products and have APIs, but their approach is not developer first. For example, Glympse has guidelines for developers to showcase Glympse branding[1], something I personally as a developer don't appreciate, especially when some of the views are consumer facing. Or the fact that Pathshare's SDKs[2] haven't been updated in more than a year, even though their app has had multiple updates recently. As a developer tool, we focus on enabling developers to build location features in their apps, with the latest and greatest of our product running silently in the background.

[1] [https://developer.glympse.com/docs/core/guidelines](https://developer.glympse.com/docs/core/guidelines) [2] [https://github.com/freshbits/pathshare-sdk- ios](https://github.com/freshbits/pathshare-sdk-ios)

<comment><USER15> Thanks. Good luck!

</comment></comment></comment></comment></comment><comment><USER16> could this be used to roll your own uber?

<comment><AUTHOR> Yep. Location based assignments and live order tracking are two of our most popular use-cases.</comment></comment>


The universe is big. This big. - <AUTHOR> http://blogs.discovermagazine.com/badastronomy/2012/03/23/an-ultradeep-image-thats-full-galaxies/ <comment><USER2> This [0] IMHO gives more perspective (don't be taken aback by the flashy images, the good stuff comes after, ~2:50 mark) When watching, remember this is when looking at _the absolute darkest spot_ of our sky.

[0] Hubble Ultra Deep Field in 3D <http://www.youtube.com/watch?v=oAVjF_7ensg>

PS: Inevitably, the title reminded me of this:

       Space is big. You just won't believe how vastly,
       hugely, mind- bogglingly big it is. I mean, you
       may think it's a long way down the road to the
       chemist's, but that's just peanuts to space.

       -- Douglas Adams, The Hitchhiker's Guide to the Galaxy

<comment><USER3> I still remember the time I saw the first Hubble Deep Field. The idea that the researchers could point this massive telescope at an empty part of the starfield, run a long exposure, and come back with a plate full of galaxies full of solar systems full of planets, while we've yet to get too far beyond the surface of our own.

A lot of people's first reaction always seems to be "we're so insignificant!" And yet, most fascinating to me is trying to reconcile the vast complexities of our planet and of humans with our physical near-nonexistence in the universe.

We have infinite complexity in approximately zero space. Kind of a strange thing to consider.

<comment><USER4> "A lot of people's first reaction always seems to be "we're so insignificant!" "

Neil deGrasse Tyson often counters this reaction by pointing out that while the universe is vast, we are made of it. So we are not simply small separate objects in a large universe, we are actually part of the physical elements that make it up and come from the same "stuff". At least that's what I gather when he says this:

"Recognize that the very molecules that make up your body, the atoms that construct the molecules, are traceable to the crucibles that were once the centers of high mass stars that exploded their chemically rich guts into the galaxy, enriching pristine gas clouds with the chemistry of life. So that we are all connected to each other biologically, to the earth chemically and to the rest of the universe atomically. That's kinda cool! That makes me smile and I actually feel quite large at the end of that. It's not that we are better than the universe, we are part of the universe. We are in the universe and the universe is in us."

<http://www.youtube.com/watch?v=VOzkEwaMnaE> [http://www.goodreads.com/author/quotes/12855.Neil_deGrasse_T...](http://www.goodreads.com/author/quotes/12855.Neil_deGrasse_Tyson)

<comment><USER5> Feynman countered this by saying we're extremely large compared to atoms and fundamental particles, so we can "sit in the middle and enjoy everything both ways."

<http://www.youtube.com/watch?v=nmzHQljJ4bc>

<comment><USER6> I remember reading a quote once and you will have to forgive me for not remembering who said it but the approximation of it was "all will be known when the scientist looking trough the telescope, see the scientist looking back at him, through the microscope on the other end". I though it was a great quote about the recursiveness about the big questions. That amazing part about it is the relevance of it, we really don't know how big or small we are it is all perspective, for all we know the universe is a singularity in another perspective. If you traveled far enough fast enough and looked back on the universe it would be a singularity, as time and distance are related so you would be looking at the universe pre-big bang or from the perspective of distance however you want to view it.

</comment></comment></comment></comment></comment><comment><USER7> How many galaxies are in the observable universe?

Quick numbers check:

Author estimates over 200k galaxies in the image. Image covers 0.004% of the sky.

200000/0.00004 = 5,000,000,000 galaxies. (edited, thanks to % help from commenters below)

Finding somewhat standardized values for this rather standard question is frustratingly vague. Estimates range from a few billion to a trillion, though the most frequently quoted number I could find was about 100 billion.

The standard for measurement in the last 10 years or so have been the Hubble Deep Field Survey images. In the last one done, there were about 10k galaxies shown. The HDFS had a square arcminute resolution of 11.5. It would require 12,913,983 HDFS-type images to cover the entire side. (ref: <http://curious.astro.cornell.edu/question.php?number=720>)

Using these numbers: 12913983 * 10000 = 129,139,830,000 galaxies.

So why the vast difference between the two numbers? My supposition is the new ESO image isn't as deep as the HDFS.

I would argue the larger number, ~129.134 billion galaxies is a bit more accurate.

Damn, 129 billion galaxies. Someone else _has_ to be out there.

<comment><USER8> Galaxies are not evenly distributed. But for all I know this is an unusually sparsely populated part of the sky. Still, your number could shift in either direction by quite a lot.

<comment><USER7> That is an excellent point. To further refine the estimate we need measurements of the number of galactic clusters and their various densities. For example, in the Local Group (Milky Way, Andromeda, etc) there are about 50. The Virgo Supercluster contains over 2500. Getting those estimates is beyond me at the moment.

Galaxies are strung out across the universe along filaments, with vast voids in between. The voids are mostly empty and very cold, but recent observations have found hot spots in some up to millions of degrees. Overall, the universe has a soapy appearance, i.e. lots of space with the "stuff" strung together.

One thing to note is that, at least to my knowledge, there are galaxies in all directions. There may be voids along the way, but you'll always see them closer or further away.

One of the reasons that this ESO deep field view is important is that its bigger than the original Hubble Deep Field, so we can start answering questions about density and distribution.

</comment></comment></comment><comment><USER9> I still remember when I learned that the Sun was a star. I was six years old when my uncle told me about it. I actually asked him what the Sun was and his answer pretty much shocked me to the core. I already knew the Earth revolved around the Sun so learning that the Sun is just one of little tiny bright lights at night was a true eye opener. That night I looked up the sky again and wondered if there are other people up there.....

<comment><USER10> _was_ a star? :)

<comment><USER9> Oops misstype! We still have 5 billion years before we could refer to it as "was a star".....lol I just type what comes to mind and rarely do editing.....

<comment><USER3> Actually, in narrative writing, as you were doing, you should use consistent tense. So you were correct to use "was," as the sun was a star back then, independent of the fact that it also is now.

<comment><USER9> That's probably why it just came naturally to me because I do read quite a bit and may have seen this word arrangement many times before. My subconscious mind were just spitting out words as I write them. English is only my second language though, I am so much better in Filipino.....lol

</comment></comment></comment></comment></comment><comment><USER11> Totally unrelated to the universe (but maybe not): To me the "Ye. Gads" moment came after this quote:

"There's a long jet of material apparently coming from that bloated galaxy on the left (I increased the brightness and contrast of this picture to make it more obvious; it was subtle in the original image but I have a lot of practice picking out things like this)."

I am once again totally stupified at the level of image processing a trained brain paired with a good visual system can do. One day, instead of developing complicated image processing algorithms, we will have it done by a brain-in-a- vat & computer implant combo, using different animal brains and visual systems for different applications, e.g. an owl or eagle for detecting pinpoints of light in a large image of the universe.

</comment><comment><USER12> I'm surprised someone hasn't converted the large image over to something like the Google Maps navigation UI for better viewing. I guess I'll be attempting that when I get home from work.

<comment><USER13> Check out <http://zoom.it/VGFr>

<comment><USER13> I also converted the 450mb tiff <http://zoom.it/dNMW>

<comment><USER14> Wondered why it was Silverlight, then realised the site is owned by Microsoft.

<comment><USER13> The site will use javascript if you don't have Silverlight installed, so it's not a requirement.

</comment></comment></comment></comment></comment><comment><USER15> "A long time ago in a galaxy far, far away," is beginning to sound a lot more plausible.

How could there _not_ be a few Death Stars inhabited by English-speaking humans somewhere in one of those galaxies?

<comment><USER16> > _How could there not be a few Death Stars inhabited by English-speaking > humans somewhere in one of those galaxies?_

I know this is just a tongue in cheek comment, but I actually thought it somewhat reasonable until recently when I spent a moment with the numbers and saw its impossibility.

Basically, there's only ~100 billion galaxies with ~100 billion stars each (to an approximation of several orders of magnitude...), while the space of possible societies, languages, histories, etc, grows exponentially.

Even if there were 10^100 stars, log_2(10^100) is still only about 330. This means all those stars can only accomodate 330 forks in history where it could have gone one way or the other with equal probability. Or, in computer science terminology, all those stars can only encode 330 bits of information. And describing English alone takes far, far more than 330 bits. (Depending on how inevitable language of a certain type is.)

<comment><USER17> > This means all those stars can only accomodate 330 forks in history where it > could have gone one way or the other with equal probability. Or, in computer > science terminology, all those stars can only encode 330 bits of > information. And describing English alone takes far, far more than 330 bits.

There's a huge gap in your logic here. The number of bits to represent all the stars in the universe has nothing to do with the possibility that there is some English speaking society out there.

</comment></comment></comment><comment><USER18> The tip of your little finger held at arms length would about cover this image.

</comment><comment><USER19> Interestingly we don't actually know how big our Universe is, perhaps even within a great many orders of magnitude. This is because the visible Universe has expanded at sub-light speeds over its history, but in the very, very early Universe there was a period called inflation in which space-time expanded at speeds much faster than light.

<comment><USER20> >> _very early Universe there was a period called inflation in which space- time expanded at speeds much faster than light._

References for this?

<comment><USER19> <http://en.wikipedia.org/wiki/Inflation_(cosmology)>

</comment></comment></comment><comment><USER13> Looks like the image has been added to zoom.it. You can browse the full resolution image without downloading all of it: <http://zoom.it/VGFr>

</comment><comment><USER21> How can you NOT want to travel the universe when you see such a wonderful photo ? Imagine going closer and closer to a perfectly spiral shaped galaxy, effectively discovering a new world, all-so-different yet similar to ours... I get goosebumps just thinking about this..

I know I'm very probably not gonna get to leave Earth in my lifetime, but I genuinely hope that my children or grandchildren will. This opens so many possibilities...

</comment><comment><USER22> With all this out there it leaves one to wonder, when will the aliens finally get here?

But really, if we evolved from chaos and minerals (so far that's the best explanation anyone's given me.) Then somewhere on some of these other planets are sentient creatures looking up going, "I wonder if there are other sentient creatures out there?"

<comment><USER23> No doubt! It is exceedingly egotistical to think that we are the only life- forms in this vast expanse.

Also, this image seems like a good use of the iPad 3 retina display...

</comment></comment><comment><USER24> Ask a scientist: Can you see black hole lens effect in this?

</comment><comment><USER25> I love that image. It's very hard for me to begin to comprehend the numbers involved.

See also "animated scale of the Universe" from NASA.

(<http://apod.nasa.gov/apod/ap120312.html>)

<comment><USER26> That is pretty impressive. I wish there was something like this that showed travel between two points, say earth and Alpha Centauri, but at lightspeed or faster with a timer in years at the bottom like an odometer. I imagine that would impart a greater sense of scale for myself.

</comment></comment><comment><USER27> I don't understand one thing: how can they keep the telescope stable and focused so accurately on one spot in the sky, without any jitter? The Earth is rotating at 360 degrees/24 hours, which is about 0.25 degrees per minute. This 17000 pixel image covers 1.2 degrees, which means the light is sweeping across this sensor at 60 pixels/second as the earth spins.

How can they move the telescope so accurately that a sensor pixel picks up light from the exact same spot in the sky for an extended duration of time?

<comment><USER28> I think you just answered that, right before asking it.

<comment><USER27> So you're saying that we have the ability to make sure that a pixel on the sensor is collecting light from the exact same spot in the sky for an extended amount of time? Taking into account (among other things) the rotation of the earth, the shaking of the ground, the wind, the changes in the atmosphere's temperature and humidity and god knows what else?

That's pretty f'in awesome!

</comment></comment></comment><comment><USER16> To put this image in further perspective, take a look at this link[1]. It blew my mind as I had the universe and observable universe all mixed up conceptually. For instance, the universe was _not_ a point at the big bang: only the observable universe was.

[1] <http://www.astro.ucla.edu/~wright/infpoint.html>

</comment><comment><USER29> Torrent of the large jpg file: <http://thepiratebay.se/torrent/7134685/The_universe_(JPG)>

</comment><comment><USER30> If you want a more interactive look at the universe go here <http://htwins.net/scale/> (Flash but so so worth it)

<comment><USER31> You may also look at an alternative version at <http://htwins.net/scale2/>

</comment></comment><comment><USER32> Composite of the ESO image with Blue Marble 2012: <http://flic.kr/p/btoRfL>

</comment><comment><USER33> The world needs more images like this to inspire the scientists and adventurers of tomorrow.

</comment><comment><USER34> Reading into the article I got a huge urge to re-read the Foundation series (and maybe get into that prequel I never got into).

</comment><comment><USER35> Makes me feel very small.

</comment><comment><USER36> Amazing. All those galaxies and Earth is the only one with life.

<comment><USER37> Well if another galaxy has life in it we'll probably never find it.

<comment><USER38> Not with that attitude, we won't!

<comment><USER37> Dude, it's not about the attitude, it's about the numbers. The closest galaxy is four million light years away. Unless there is a major scientific breakthrough in the eons to come that will allow us to travel at speeds 100 times the speed of light there is practical no way to make such a trip. Even with a speed like that and taking under consideration the special relativity which says that time for those traveling will be passing a lot slower than for the rest of use, you'd need at least a millennium to do such a trip.

<comment><USER6> So you don't try to short cut the laws of physics you fix the weakest links, the biggest one being the longevity of humans. It is realistic to think that given enough time we will be able to replicate organic machines with electro- mechanical ones. Someone somewhere is going to volunteer to upload themselves into one of these machines and we blast them off into space. In the end we always seems to achieve the dreams of the human spirit, 9 times out of 10 they are never the way we envisioned we would. Take flight, early man envisioned wings like a bird and not machines like a plane, but in the end we achieved flight something many people said would never happen, that I am sure of. I think we will achieve intergalactic travel, but it will be nothing like what we envision it to be today, something will come out of left field that will enable it. The challenges are daunting but so was flight at one point in human history.

<comment><USER20> Exactly! in the future, One can build robots or artificially intelligent machines that can travel and make some decisions on themselves. Such machines will not need most biological conditions needed for organic life to survive. So can live in many hostile conditions.

They can also clone themselves mining the resources and energy available at anywhere they land.

Such machines can colonize the space.

<comment><USER39> I personally think the chances are high that humanity will simply self- destruct before it can achieve anything like this.

<comment><USER6> I think the actual feasibility of man made annihilation is smaller than what it is made out to be by the media and entertainment industry. The two most popular ways that are highlighted are nuclear war or bio-engineered pathogen. As far as the first one goes, nuclear war will only eliminate the population centers and irradiate everything, there would be survivors and they would adapt to the conditions.

The second, a pathogen, is just as unlikely to get every last one of us. A virus with a 100% kill rate is highly unlikely. Look at Ebola, while weaponized Ebola would get a great deal of us it's kill rate is somewhere in the 90%'tile, I don't know the exact number but I know it is high and I believe that it is the highest. 10% of the earth population is still allot of people. Even if it is less than that, somewhere their will be a group of people that for whatever reason are resistant to the pathogen.

The only thing that I think is a real threat to our existence today, is a big piece of something floating around out there, deciding to slam into us down here. I don't think we have the capability to do it to ourselves. I heard someone say that it is likely that we will keep resetting ourselves back to the stone-age at a certain mark in technological progress, which I think is a little more feasible, but I personally believe that mans desire to cull different people is self regulation for whatever reason.</comment></comment></comment></comment></comment></comment></comment></comment>


Why the normative form of IETF standards is ASCII - <AUTHOR> http://www.ietf.org/mail-archive/web/ietf/current/msg60589.html

<comment><AUTHOR> More detailed information about why the IETF continues to use ASCII (and not UTF-8) from Martin Rex:

[http://www.ietf.org/mail- archive/web/ietf/current/msg60573.h...](http://www.ietf.org/mail- archive/web/ietf/current/msg60573.html)</comment>


P vs NP on simple english wikipedia - feedback, please - <AUTHOR> http://simple.wikipedia.org/wiki/P_versus_NP <comment><USER2> Your example at the end - you should go in to less detail about the number of combinations, and more in to how it's easy for a computer to check the right answer has been reached.

<comment><USER3> This. It's a really great example, but you never make the full connection by explaining that it's easy to check that 2 towers have the same mass.

</comment></comment><comment><USER4> I see posting this here as a mistake. You should post it somewhere where people dont know anything about it. Posting it here will result in us adding more and more detail, possibly making it more complicated.

I used to use my grandmother as a subject for testing out paper abstracts/intros for this reason. She could barely figure out scrolling.

</comment><comment> buff-a My 2c: Don't write "Problems in P", write "P Problems".

Also you definition of "why its interesting" conflicts with the other Wikipedia page which says:

 _The P versus NP problem is a major unsolved problem in computer science. Informally, it asks whether every problem whose solution can be efficiently checked by a computer can also be efficiently solved by a computer._

<comment><AUTHOR> i'm not sure i see the conflict... care to elaborate?

<comment> buff-a He's changed it =)

This is what it said originally: _That means they would like to know if there are any problems where the answer cannot easily be found by a computer, but if someone says he has the answer, it is easy to use a computer to check if that answer is correct._

</comment></comment></comment><comment><USER5> I think you might be missing the point of the simple English wikipedia. It's the vocabulary that you use that is simple, not the way in which you express the concepts.

<comment><USER6> I somewhat agree. For example why use a term like 'mass', when 'size' or 'weight' would be much simpler.

<comment><USER7> and wrong

<comment><USER6> In what way is the word 'size' wrong?

<comment><USER8> I guess that Lamby means that one should not use "weight" instead of "mass", the two being two very different concepts.

<comment><USER9> They're very different concepts, but for the sake of the example it doesn't matter which you are measuring, you could equally be measuring the number of atoms in each one if you happen to know it.

</comment></comment></comment></comment></comment></comment><comment><USER10>
      P problems are considered 'easy' for computers to solve. NP problems are considered easy for computers to check the answers to them.

To improve clarity:

1\. Avoid putting pronouns far from the main noun.

2\. Use simple sentences. Reduce the number of verbs and prepositional phrases per sentence.

3\. Avoid scare quotes. If you need to qualify a term, do so explicitly.

Consider, for the above:

NP problems have answers which can be easily checked. P problems can be easily solved.

(Maybe precede or follow with a quick definition of what you mean by 'easy.' But I'm not sure it's necessary here.)

</comment><comment><USER11> i guess the article is currently being edited, but at the moment it isn't so clear what is common and what different between the two groups. i think it would be better if the motivation came earlier:

      solving a problem is sometimes harder than checking you have the right answer.
      for example, it is easy to check that you have the secret key to a code.  you
      can decode a message and see the original text.  but it is hard to find the key
      if you do not know it.

      so the problem of finding the key to a code is much harder than checking whether a
      key is correct.  other problems can be easy to solve and to check.  for example,
      adding 2 and 2 is both easy to solve and to check.

      this difference can be used to divide problems into two groups.  these groups are
      called P and NP.  it is easy to check the answers for problems in both groups,
      but only problems in group P are easy to solve.

      the problem of adding two numbers is in P, because it is easy to solve and to
      check. the problem finding a secret key to a code is in NP because is is easy to
      check but hard to solve.

i know my writing isn't simple enough here, but an approach like the above makes it easier to understand the relationship between them. in particular, the commonality between the two groups is emphasised.

<comment><USER12> I had a similar response to the article, but I can see at least one reason why this explanation doesn't fit. Despite any inclinations we may have P vs. NP is still unsolved. So, claiming that a problem is in NP is "easy to check but hard to solve" is not necessarily true (if P == NP, it is both easy to check and to solve).

The original article does a good job of not making this assumption, and because of this gains the ability to pose the question:

> Many people want to know if there are any NP problems that are not P > Problems

<comment><USER11> hmmm. it's true that my text is wrong in that way, but couldn't you fix it with a "maybe" or "appear" and then explain the open question afterwards? or maybe the conditional nature of the text then becomes too complex?

</comment></comment></comment><comment><USER13> You might want to mention P VS NP is similar to the following scenario: people feel they can identify a piece of art (say a painting) as being of merit very quickly just by seeing it; but won't be able to come up with any piece of equal merit even if they had all the time in the world.

</comment><comment><USER14>
      Many people want to know if there are any NP problems that are not P Problems.
      That means they would like to know if there are any problems where the answer
      is hard to find, but if someone says he has the answer, it is easy to check
      if that answer is correct.

This is probably the core of the article, but I find it misleading. The truth is that we need to either prove that the answer to a certain problem will always be hard to find (hence proving that P =/= NP) or we need to prove that all NP problems have in theory a P algorithm (P = NP). We currently have many NP (="easily" verifiable) problems that have no known solving algorithm in polynomial time. The evidence would so far suggest that P =/= NP, but this is empirical not mathematical. It's possible that all those non-P problems have some way to resolve them in P, but it doesn't look like it right now.

I would thus rephrase the core explanation as something like this:

" _For problems where the correct answer can be checked easily, there are two possibilities: If (P = NP) is correct, that means there is always an easy way to come up with a solution no matter how complicated the problem is. If the opposite is correct (P =/= NP), there are some problems where the answer will always be difficult to find no matter how clever the solution is. We don't know yet which one of these possibilities is true._ "

<comment><AUTHOR> the lack of a known polynomial time algorithm could be interpreted as evidence that P =/= NP, but it could just as easily be interpreted as evidence of our primitive state of knowledge with regard to algorithms. Suppose that P = NP, but the minimum complexity of any NP-Complete problem is O(n^(# of atoms in the universe)); we might never discover such a complicated algorithm, but that in no way implies it doesn't exist.

still, i see your point, but i think your phrasing is too complicated; i've changed it to this:

      It is known that all P problems are NP problems; the proof
      requires math which is too complicated for this article but
      may be explained in the future. Many people want to know if
      there are any NP problems that are not P Problems. That
      means they would like to know if there are any problems
      where the answer cannot easily be found by a computer, but
      if someone says he has the answer, it is easy to use
      a computer to check if that answer is correct.

<comment><USER14> I like mine better ;-)

Your idea about the the primitive state of our algorithm knowledge is interesting. This has nothing to do with the article, but I do believe there are deep philosophical implications here. If we knew (and could make use of the fact) that everything is P, it would fundamentally shift our relationship with reality. I would go so far as to say that P =/= NP is an instinctive model we have formed about the universe as it presents itself today. If this were to change, it would affect pretty much everything we're doing - I can't even begin to imagine what would happen on the day abstract problem solving becomes a P algorithm...

<comment><AUTHOR> what happens in the example i gave above? if the minimum complexity of solving any np-complete problem is O(n^2e80) then we'd need such massively parallel computing that you'd have to turn pretty much every atom in the universe into a computing device.

i agree that p != np is the instinctive model most theoreticians have about the universe, but if science has taught us anything in the last 100 years, it's that our instincts are often wrong, and the story of science will probably never be finished.

<comment><USER14> Absolutely, but I'd say that the idea of brute-forcing the entire universe - while theoretically and mathematically sound - goes against the spirit of what we're trying to express with Big O. Solutions like these work in a theoretical universe with infinite matter and possibly over infinite time, but if the world is indeed finite (which it may very well be) any Big O expression containing the sum of all states of all atoms in the universe does contain a practical infinity.

<comment><AUTHOR> i'm not sure what you mean by the 'spirit' of Big-O; i find the question fascinating because it is relatively easy to understand the concepts involved, yet it's been 40+ years since we understood enough to be able to ask the question, and we still don't know the answer. when you couple that with the fact that the prevailing wisdom that our inability to find an algorithm implies that it can't exist, the contrarian in me goes nuts: the academic attitude is always "we're so smart, if we can't find it, it must not exist," and i get a kick out of arguing for more humility on their part.

even though a polynomial-time algorithm with a massive polynomial would still be computationally intractable, even a proof that such an algorithm exists, but is too complicated to express using all the atoms in the universe as bits would probably open the doors to all kinds of proofs and techniques we cant' even imagine.

</comment></comment></comment></comment></comment></comment><comment><USER15> The page says people "would like to know if there are any problems that are easy for computers to see if a one person's answer is correct, but hard for computers to find a correct answer." However the example given seems to answer this question in the affirmative: it's a problem that's easy to check using a set of scales, but very hard to find a correct answer.

<comment><AUTHOR> maybe the example needs to be more clear - it's hard for the computer to check all possible answers, but maybe it's easy for the computer to find the answer another way.

</comment></comment><comment><USER16> Rating 3/10. I don't think this article is written by someone who knows the topic well.

e.g. you don't too complicated math as claimed in this line:

>> It is known that all P problems are NP problems; the proof requires math which is too complicated for this article but may be explained in the future.

For P problems can be solved easily and then the solution can be easily verified. This means all P problems are NP problems too.

Good news!! Better Article Exists. Read: [http://cstheory.stackexchange.com/questions/5188/explain- p-n...](http://cstheory.stackexchange.com/questions/5188/explain-p-np-problem- to-10-year-old)

<comment><AUTHOR> I would agree that the math required is not 'complicated' from the point of view of anyone with basic understanding of discrete logic, but it's certainly too complicated to express in simple english terms that are understandable at the level i was shooting for.

if you want to do the proof that all problems in P are also in NP, you have to explain the notion of a decision problem and show that any np-complete numerical optimization problem can be converted to a decision problem without increasing its computational complexity by more than a function bounded by a polynomial.

someone named 'balabiot' changed the article by adding an incorrect 'proof' that P is a subset of NP, at the same time you made this post. the incorrect proof reads:

      All P problems are NP problems: if a problem is easy to
      solve, to check an answer you just solve it and check that
      the results match.

this invalid proof makes the assumption that an np-complete problem has a single solution. many np-complete problems have multiple solutions; there many be many ways to pack the knapsack, color the graph, or satisfy the boolean circuit. if you are presented with a valid solution, but the algorithm you use to solve the problem instance produces a different, but also valid solution, your comparison would fail.

note that simply solving the problem (because it is in p) is NOT the same thing as verifying a solution correct.

</comment></comment><comment><USER17> I came from an electronics background when I first started reading algorithms my head was spinning. And I am sure a lot of other novices/laymen from the same problem.

The reason I have seen over the years is simple. Expressing the problems in terms of mathematical equations. Mathematical equations some how denote a way of modifying elements through equations. They tend to build on existing established principles of maths. There fore in order to understand what the other person is saying a person must get into a high learning curve.

When I first read about P Vs NP problem, I really wasn't able to co relate it to anything in the real world. Later on as I read more on puzzles like The Bin packing problem, or the traveling salesman problems. Things began to make sense.

The way to explain people about such things is to give them problems defined in simple English. And then allow them to build their own way of representing objects and elements, and the way they choose to modify them. Like this article does, However while explaining to people start from very small input sizes. Help them work out outputs for large input sizes.

Given the problem at hand, explain them why such large computation time doesn't make sense in the physical world.

Representing the problem in pure math will never help the guy next to your home. Giving him a day to day use case, will force him to think.

So here we go, what all common every day use cases fit into the P Vs NP problem? If we can create such a list, a lot more laymen can think and build on those problems easily!

Is there such a list lurking somewhere?

<comment><AUTHOR> doubtful. a programmer could spend an entire career in industry and never run into an np complete problem he needed to solve.

i added more examples to the article, and made them as simple and practical sounding as possible, but to be honest my primary interest in the problem is mostly from a theoretical perspective. to me, the idea that P != NP implies a host of bizarre conclusions that seem incredibly unlikely to me. i am so convinced of this that i had it emblazoned my license plate:

<http://www.markpneyer.com/wp/about-me/>

<comment><USER17> Thanks Mark,

Good work Indeed.

Can you please explain why you think P=NP. I am deeply interested in knowing about them.

<comment><AUTHOR> to be honest, mostly it's because i enjoy disagreeing with people who are convinced of things they don't have a full understanding of. if you are decently educated, you realize how much there is we don't know, and approach every unsolved puzzle with a combination of curiosity, confidence and humility. philosophy aside, here's my thinking:

LONG VERSION: Suppose _P_ is an NP complete decision problem; for each instance, the answer is either 'yes' or 'no'. Let _P_ have verifying function _V_. Let the language _L_ be the set of all binary strings _s_ that represent instances of _P_ for which _V(s) = 1_ , i.e. the set of all strings _s_ that represent instances of _P_ for which the answer is 'yes'. If _L_ (the set of all instances of P for which the answer is 'yes') is finite, then you can easily answer all instances of the problem P in constant time by using a lookup table that stores all members of L (i.e. all finite languages are regular.)

So, consider the case when L is infinite. We know that V must be expressible in terms of a finite sequence of symbols. Suppose we have manged to express V using a total of C bits. The entropy of all C-bit binary sequences is bounded by a function of C alone; i.e. it is independent of the specific content of V, all that matters is how many bits are in some (it doesn't matter which) implementation of V. My primitive understanding of information theory tells me that if V has a finite amount of information, and L is uniquely determined by V, then L cannot possibly have MORE information than V; if you have V and enough time, you can compute all of L. This limits the possibilities of L, and suggest to me that there must be a way to find a (possibly complex and incomprehensible algorithm) for solving all instances of P, by 'compressing' L in just the right way. I admit that this is very hand-wavey; i just don't know enough information theory to pin everything down.

SHORT VERSION: if you can verify all solutions to a problem using a function expressible using a finite sequence of symbols, then the total information content of a sequence representing all solutions to the problem can't exceed the information content of the verifying algorithm.

if P != NP, this (to me) implies that a list of answers to a problem somehow has more information than an algorithm that can be used to generate that list of all answers. it seems to me that the algorithm could easily contain more information than the list, but not the other way around.

to put it another way, if you see a verifying function as a compression algorithm on the list of all solutions (because they contain the same amount of information), then P != NP implies that some infinite sequences (which represent np complete problems) are simultaneously so redundant that they can be compressed to a finite length, but at the same time are so complicated that you can't figure out an arbitrary element without doing a massive amount of computation. as i see it, some patterns can appear random unless you look at them from just the right perspective, and then the pattern emerges. because np-complete problems can be expressed with a finite amount of information, there has to be a pattern that we're not seeing yet.

</comment></comment></comment></comment><comment><USER18> I think this generally does a good job of simplifying the terminology without falling into "durr, people who don't speak English natively are dumb" territory.

<comment><USER19> I agree. Simple errs towards 5 year olds, not people whos native language is not English, as they have their own wikipedias.

</comment></comment><comment><USER20> As someone who has an interest in this kind of thing, but very little in the way of formal education on it (my last formal maths education was my 'A' levels around 25 years ago), I'm possibly the exact target audience for this article.

Given that, I thought it was very helpful. I've read a whole host of attempts to explain it before, and they rapidly descend into 1000 other mathematical concepts that I don't fully understand and end up reading about instead of the actual P v NP issue.

The one bit that I think is missing is a better explanation of what's meant by "easy" in this context. Clearly a problem that takes more than the life of the universe to solve is likely to classify as hard. But what about if it was solvable in a year, or a minute, or a second? My vague understanding is that there's not really a "less than 5 seconds to solve"-type cutoff, and that it's actually to do with "nondeterministic polynomial time". But at that point I disappear into one of the mathematical things that I don't really grasp.

<comment><AUTHOR> i agree, it could use more math. i plan to add that in; my concern is that i don't want to scare people away.

<comment><USER20> I would offer a suggestion, but I just had another go on the Wikipedia version and I honestly don't have a clue what it's telling me. I think I get what non- deterministic means, but then I'm totally flummoxed as to what that has to do with problems whose solution can be quickly verified.

</comment></comment></comment><comment><USER21> I liked the article!

I would mention that it is part of the millenium problems and the one million dollar prize that comes with it.

</comment><comment><USER22> It seems to be missing the philosophical introduction to what P = NP means [1]:

 _If P=NP, then the world would be a profoundly different place... Everyone who could appreciate a symphony would be Mozart_

[1] <http://www.scottaaronson.com/blog/?p=122>

</comment><comment><USER23> Many people find it difficult to see which of two large numbers is greater, unless they are reading on paper and take up a pencil and count the groups of three. This issue must come up a lot in simple-English. The solution is to introduce scientific notation, and to have a link to that. (As has been pointed out, _mass_ is a tricky word, being used here.) Perhaps another method would be to invent something quirky, saying perhaps "4+(20 digits)" or something.

In this particular case, there is another solution: do not quote the individual numbers, but only their ratio. Anyone can tell that "1000" is big and "1/1000" is small, because all that's needed is to see if there are more than two or so digits.

</comment><comment><USER24> I dislike the common implication that NP complete means "the stupidest brute force thing is the best way we know how to solve the problem." For example, meet in the middle will turn subset sum from 2^n to 2^(n/2).

<comment><AUTHOR> i agree that there are a lot of problems, but the goal of this article was to make the topic as simple as possible. any simplification of a complex, mathematical construct will invariably result in hand-waving and undefined terms; i tried my best to keep those to a minimum. i plan to expand the article in the future, to clarify some mathematical details. thanks for the feedback, though.

</comment></comment><comment><USER25> I suggest emphasizing that problems that can be solved easily can be checked easily. It's a simple idea, but it wouldn't necessarily occur to the casual reader and is quite important.

<comment><USER26> agreed that the example is not the best, a better example would be a picture puzzle that can be verified in just a glance but to build it you need to test all pieces against each other to see if they match.

<comment><USER27> Picture puzzle is in P because you can build the puzzle incrementally in quadratic time

</comment></comment></comment><comment><USER28> I wonder if there is a good way to explain that the nature of these problems is to find any and all _exact_ solutions to the puzzle and that the 95% solution which is vastly easier and entirely sufficient for any practical application (in terms of the given examples) is NOT interesting.

E.g.: Travelling sales-person: In terms of P/NP, she doesn't care if she _can_ as much as if there is any possible route she might take that is even an inch shorter than the one she can fairly trivially plan out.

<comment><AUTHOR> your claim that a 95% solution is entirely sufficient only applies to numerical optimization problems. every numerical optimization problem has a corresponding decision problem, and an algorithm that could solve these decision problems would be tremendously useful. think about circuit satisfiablility; if you're building an airplane, you want to know if the circuits for the airplane could ever cause the engines to shut off mid-flight. the concept of an approximation algorithm is meaningless here; either you know the answer, or you don't.

<comment><USER17> Although I understand what your are trying to say here.

But the problems you tend to describe never exist in the real world either. What I mean to say is, you can never be Boolean sure about anything in the real world as you can never control all the parameters yourself.

Which in case you are always going to measure things in percentages like x% safer or y% safer.

I guess that's what the parent poster tends to imply.

<comment><AUTHOR> you can never control all of the parameters yourself, true, but think of it this way:

the cockpit of an airplane has hundreds of switches and nobs. suppose we want to ask the question "is there some way the pilot could toggle switches or flip knobs that would open the doors in flight?" you're never going to be able to guarantee that the doors won't open, but you can guarantee that the circuit alone won't cause them to open.

or, consider that many games are np-complete. if you are playing such a game against another player, whoever gets the better solution will win.

in addition, the original author's claim that the 95% solution is "vastly easier and entirely sufficient" _may_be true for the numerical optimization problems given in the example, but there are most certainly np-complete problems which cannot be approximated to any degree of accuracy.

for example: given a graph, the max-clique problem asks 'what is the largest fully-connected subgraph?' this problem arises very naturally in social networks; it's equivalent to asking 'what is the largest group of people who are all friends with each other?' This problem cannot be approximated within ANY bound of the optimal solution unless P = NP. The same problem arises in computational biology and chemistry as well.

<comment><USER28> That's a very good point, but my concern is that the provided examples dumb down issues to a level where this is not easily understood. I mean, who gets closer to grasping this nuance bu supposing a woman building towers of rocks on the beach?

Actually, I think the cockpit-switches-example would be a valuable example.

</comment></comment></comment></comment></comment><comment><USER29> A picture like this <http://en.wikipedia.org/wiki/File:Exponential.svg> would help.

To rub it in, the x axis should go to 20 or so, e.g. [http://www.wolframalpha.com/input/?i=2**x+vs.+x**2+%28x+from...](http://www.wolframalpha.com/input/?i=2**x+vs.+x**2+%28x+from+0+to+20%29)

</comment><comment><USER30> This sentence doesn't read quite right to me: "Most mathematicians also believe that are any NP problems that are not P problems."

It feels like there are a couple of words missing, but I'm reluctant to guess at them and potentially change the meaning of the sentence.

</comment><comment><USER31> I think your subset sum problem (the rock piles) is decent. However, for it to be useful I think you have to make it clear which class it is in (NP) and why (it is easy to check a solution and 2^n is not polynomial in n).

</comment><comment><USER32> The real difficult part of explaining this concept to the layperson is getting them to understand what asymptotic complexity is. The example I always use when I explain this to people with little or no math or computer science background is sorting algorithms, explained using the following example of a deck of cards. Everybody's familiar with a deck of cards, and it doesn't take much more math than the most intuitive bits statistics.

Imagine I give you a deck of perfectly shuffled (i.e. uniformly distributed) cards, and decree that you need to find the ace of spades. What you have to do is go through each card one-by-one, and stop when you've found it. You'll have to look at, on average, 26 cards, since there are 52 cards in the deck, and each card has an equal chance of being the ace of spades. Now, let's say I add another 52 cards, this time with a defaced ace of spades, and wanted you to find the original (non-defaced) ace of spades, which is now just one card out of 104. On average, this'll take 52 cards.

Notice that when I double the amount of cards I gave you, the amount of work (that is, looking at cards) you had to do also doubles, meaning that for N cards, the amount of work is N/2. When the amount of work is directly related to the number of cards, excluding dividing or multiplying by a number that does not depend on the number of cards (in this example, dividing by 2), then we simplify things and say that this process for finding the Ace of Spades takes BigO(N) work to finish.

Now, imagine I give you that same deck, and instead of demanding that you find the ace of spades, I require you to sort it out into suits, with the cards in each suit in increasing order. One way to do this is to keep a separate pile for each suit, with that pile in increasing order. Deciding where to put the first card of each suit is easy, you just make a new pile for it. The later cards are not as easy, since you have to go through the pile and find the right place to put the new card.

Right away you can tell that this sorting takes more work from you than finding the ace of spades does. Instead of just looking at each card to see if it's the ace of spades, you first have to check the suit of the card to determine which pile it should go in. Then, you have to look through that pile for the proper place to insert the card. I won't go into the math, but it turns out the best way to sort a deck of cards into piles of suits[1] like this takes N * lgN work, where lgN is a fancy number that isn't constant, but gets bigger when N gets bigger, unlike the division by 2 in the ace of spades example. That means that sorting cards is harder than finding the ace of spades.

This business of determining how hard tasks like sorting cards are is called "analyzing the complexity" of a task. Except, instead of saying task, computer scientists like to say "function." The question of whether or not P = NP is a question about whether a certain kind of tasks called "deterministic Polynomial" tasks (which are referred to by the P) are as hard as another kind of tasks called "Non-deterministic Polynomial" tasks (referred to by the NP).

I have a second part that tries to explain the difference between determinism and non-determinism using a magic deck of cards where we can always draw the card that we want (the "magic" deck is, of course, merely a "non- deterministic" deck), but I've already spend an hour or so writing this first part up. I can post the second part of the explanation tomorrow, if folks are interested.

[1]: This is meant to be a memory constraint. Obviously, radix sort takes linear time too if the key sizes are constant, but has a memory overhead of N. As far as I'm aware–and please correct me if I'm wrong–the fastest sorting algorithms with constant memory overhead are comparison-based sorting algorithms, which take N lgN time. But, even if I am wrong, it's incidental to the main purpose of the explanation.</comment>


Congress Is Making Plans To Limit Use Of Military Drones - <AUTHOR> http://www.popsci.com/article/technology/congress-making-plans-limit-use-military-drones

<comment><USER2> You mean I can't have my own predator with Gatlin gun and hellfire missiles, government over reach!</comment>


ULID – Chronologically sortable drop-in replacement for UUID - <AUTHOR> https://github.com/alizain/ulid <comment><USER2> niftich's comment at [https://news.ycombinator.com/item?id=12205158](https://news.ycombinator.com/item?id=12205158) , from when this was posted 12 days ago, is unanswered:

> For what it's worth, the UUID RFC actually has a provision for using random > bits instead of the MAC address in a version 1 UUID [ref], which results in > a similar, but incompatible structure as to what's proposed here.

> I'm not sure what this new, incompatible format buys over that one, other > than a different allocation of bits between the time and random fields.

> [ref] > [https://tools.ietf.org/html/rfc4122#section-4.5](https://tools.ietf.org/html/rfc4122#section-4.5)

niftich also gave an ASCII drawing of the bitfields in a ULID vs. UUIDv1.

<comment><AUTHOR> Didn't know it had already been posted, thanks! I'm answering it now

<comment><USER2> You're welcome. I don't actually use UUID's so can't comment about.</comment></comment></comment>


Office 2011 for Mac Isn't an Improvement - <AUTHOR> http://pogue.blogs.nytimes.com/2010/10/21/office-for-mac-isnt-an-improvement/

<comment><USER2> This is a huge disappointment for me. I teach and try to keep up with the (MS) software that my students are using so I can offer some tech support (though I'm not about to switch to Windows for their sake).

But the type of issues that aggravate Pogue are exactly what annoy me in software UX. Someone's going to have to write an mighty effective rejoinder to his review of MS Office to get me to follow _this_ "upgrade."</comment>