Teacher Effects on Student Achievement and Height: A Cautionary Tale - <AUTHOR> https://www.nber.org/papers/w26480 <comment><USER2> Summary: schools are rewarding teachers based on "value-added measures" that try to measure the effect of the teacher on the student's educational progress. The paper shows that these models are mostly picking up unrelated differences between student populations, by showing that the same approach would reward teachers for having taller students.

<comment><USER3> Could be a landmark paper. At a minimum, it shows that all evaluation methods should completely negate teacher's impact on height. It seriously calls in to question a ton of research that I would have assumed to have been good.

Excellent work by those that wrote the paper.

<comment><USER4> It appears to be an important research study, but in the sense of implication to educational policy, not so much.

The reason is, for one, the use of value-added measurement does not have a significant role as many would think. There is not a signle state in the U.S. use VAM as a single measure of teacher performance, nor a determinant factor in teacher firing or promotion. It is always mixed with other quantitative and / or qualitative measures (which usually are no better than VAM).

The second reason is, the research community has not find a better replacement yet. We always know we cannot directly use student achievement, now we know we cannot trust a more complicated measure such as VAM which takes into account of student history and other factors.

<comment><USER3> The world is moving toward multifactor models like VAM. This paper introduces a crucial test to determine whether a VAM is applicable or not.

</comment></comment></comment></comment><comment><USER5> I worked as a teacher in, state funded, education for 15 years.

Value added measurements of student achievement will always fail.

In affluent areas, where student achievement is already high, schools can afford to hire the best teachers, but they will realistically only be able to boost achievement by a small fraction, given the child's prior attainment.

In deprived areas, where student achievement is lower, schools can only afford to hire less qualified teachers, and the boost to achievement will be a small fraction of previous attainment.

Either way, the measured effect that the teacher has will be marginal, while common standards and common testing are the only measured outcomes. This does not equate to the teachers not being invested in student outcomes, or trying their best for their students.

Value added measures were only introduced as a form of target setting, for teacher performance. I'd encourage everyone to watch Adam Curtis' The Trap[1] to see the effects of target setting.

Teachers in early years education set a target, then primary school teachers need to show value added so game the system to show improvement. This trickles up the system, and the net result is unrealistic targets for almost every child as they exit formal education.

[1][https://en.wikipedia.org/wiki/The_Trap_(TV_series)](https://en.wikipedia.org/wiki/The_Trap_\(TV_series\))

<comment><USER6> The problems of students and schools in low SES areas go way beyond teacher quality and student educational achievement.

More explicitly, there are many excellent teachers in poor areas. Teaching privileged children in a well funded school is much easier.

<comment><USER7> In my city there a 5 high schools which perform remarkably differently despite having the same source of funding and teachers. The high performing school is probably in the 99 percentile in the state. If you look at the schools, that high performing one looks the most beaten down. I think it all comes down to the affluence level of the parents, their education levels and what they impart on their kids.

</comment></comment></comment><comment><USER8> The problem with using height is that there is already evidence that taller people are more successful due to hidden biases.

So perhaps the teacher measures were still valid because all the tall people were more successful because of other biases in the system?

I'm mostly just being cheeky here. To be clear, I still think it's nearly impossible to measure how good a teacher is based on student performance, since the teacher is only one part of the equation, the parents (and the student's home life) being a much bigger part of the equation. The teacher can only do so much if the child comes home to parents that don't feed them and tell them they are worthless.

<comment><USER9> > The problem with using height is that there is already evidence that taller > people are more successful due to hidden biases.

IIRC, while it has been shown that taller people are more successful, and everyone says it is due to "hidden biases", those hidden biases were not in fact shown.

A competing theory that I am familiar with, which provides just as good (if not better) explanation is this:

Height is a (bad) proxy for healthy upbringing. Your maximum height is essentially genetically predetermined. But to actually attain that height, you have to have good everything growing up -- good food, good health. If you do not have access to nutritious food, or you are plagued with diseases that impact your growth (.. or treatment for them [0]), you will be shorter. So:

Tall = Tall Genes + Good Environment

Short = Short Genes + Good Environment ; or Tall Genes + Bad Environment

Thus, tall people are correlated with good environment growing up, and shorter people less so -- and the theory is that it is the environment you grow up in that explains your success, rather than some hidden biases.

<comment><USER10> IANAS, but from what I understand, it's more complicated than that. A parent's or grandparent's childhood health has been shown to affect the growth and health of their descendents. These effects only go away after several generations of adequate nutrition and health. Tall women tend to give birth to larger babies not (directly) because of a "tall gene", but because of the physiological realities of their bodies (i.e., more space). We've recently identified several traits that are hereditary and that can stunt growth, but that had previously not been linked directly to a given family's shortness (e.g., sleep apnea and gluten sensitivity), and which have interventions much less radical than genetic modification.

It _seems_ clear-cut, and there are studies that link certain genes to height on a statistical level. But I suspect we're going to find that height has little to do with genetics in the traditional sense, and outside a few notable outliers, that there are no "short genes", just environments that fit specific genetic profiles that are or are not available to the people with those genes. Europeans are tallest in a generalized global monoculture where Western diets and lifestyles are the norm, and where European-descended populations have enjoyed a generally higher quality of life for several generations. Color me surprised.

<comment><USER11> Often what looks like an effect of grandparents on kids (controlling for parents) is just genetics -- what you observe in the parents is a noisy measure of some hidden variable, and the grandparents give you additional (noisy) data.

> outside a few notable outliers, that there are no "short genes", just > environments

Predictions based on about 20000 different genes gave correlation 0.65, in the best paper I can find in 5 minutes. (Which was from 2017, a long time in this game.) This is for differences within a European-descended population.

<comment><USER12> There was a study a while back, based on family records out of scandinavian churches, where they were able to identify patterns in children based on when (or if) their paternal grandfathers had experienced mild famine in a narrow age range.

They were further working to tie these effects to a group of epigenetic markers. (possibly successfully, I'm unclear.)

It may have been this study: [https://en.wikipedia.org/wiki/%C3%96verkalix_study](https://en.wikipedia.org/wiki/%C3%96verkalix_study)

<comment><USER11> I do not know this study, but sentences like "paternal grandfather's food supply was only linked to the mortality RR of grandsons and not granddaughters" in a study with N=303 make me pretty skeptical about p-hacking.

There's a lot of academic interest in such things, precisely because they go against the grain of everything that's well understood. Finding one, and proving that it's really certainly not zero, could make your name.

</comment></comment></comment></comment></comment></comment><comment><USER13> This would have been a perfect opportunity to cite the paper about the efficacy of parachutes: [https://www.bmj.com/content/363/bmj.k5094](https://www.bmj.com/content/363/bmj.k5094)

<comment><USER14> Too slow to make the connection here... can you explain your reasoning?

<comment><USER15> It seems to be a contrived joke: They tested people jumping with and without parachutes from a small airplane situated on the ground.

<comment><USER16> It's a follow-up to a previous article bemoaning the lack of a randomised controlled trial of parachutes and arguing that they should not therefore be accepted as a valid 'treatment' for falling out of an aeroplane ([https://www.ncbi.nlm.nih.gov/pmc/articles/PMC300808/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC300808/)).

Both this article and its predecessor were published in the Christmas issue of the BMJ, where funny papers with a semi-serious point (in these cases, the ongoing debates in medicine about the superiority of RCTs over other forms of clinical evidence) are common.

My favourite of this genre is "Does Peppa Pig encourage inappropriate use of primary care resources?" ([https://doi.org/10.1136/bmj.j5397](https://doi.org/10.1136/bmj.j5397)) critiquing the clinical practice of Dr Brown Bear, a fictional cartoon GP.

<comment><USER17> My favorite BMJ Christmas article is a study of self-reported virgin mothers [1], but I might be biased because I know one of the authors.

[1] [https://www.bmj.com/content/347/bmj.f7102](https://www.bmj.com/content/347/bmj.f7102)

</comment></comment></comment></comment></comment><comment><USER18> It's not totally beyond the realm of plausibility for teachers to have long- term effects on height, given the effect of childhood nutrition on height. Properly feeding children can have such a positive effect on their academic achievement that some teachers end up doing it out of their own pocket. Certainly the best way to raise the worst-performing children is "fixing" whatever disaster family situation they are dealing with at home.

<comment><USER19> Teachers are not feeding kids in statistically significant volumes. Schools are, and there might be correlations.

<comment><USER20> Is it possible that good teachers hang out in the lunchroom and encourage their students to eat? I don't think it's fair to so readily dismiss the hypothesis without a good look at the relevant data.

<comment><USER18> Good teachers manage to prevent their school enacting bad policy like this: [https://edition.cnn.com/2019/11/19/us/school-lunch-debt- dona...](https://edition.cnn.com/2019/11/19/us/school-lunch-debt-donations- trnd/index.html)

</comment></comment></comment></comment><comment><USER21> For children who are still growing physically and mentally, both height and intellectual development are correlated with age, aren't they?. In an analysis where you are treating children who actually have a range of ages as a single age (i.e. "5th graders") finding some correlation between height and intellectual development isn't that surprising. It is just an expression of the underlying correlation between their age and intellectual development.

<comment><USER22> Height is generally correlated with IQ, though not very strongly (r = 0.2), and IQ is very strongly correlated with education success. It is also known that this correlation is not spurious: half of it is pleiotropy, which is, some of the genes that cause taller height also cause higher intelligence, and half of it is due to assortative mating, meaning taller people tend to have children with other taller people, so if pleiotropy causes taller people to be more intelligent, the tendency to marry taller people additionally amplifies the correlation.

Keep in mind though that the correlation, while very highly statistically significant and replicated over many data sets, is not very strong: at r = 0.2, the r^2 is 0.04, so only 4% of variance in intelligence is explained by height. Thus, it is not clear whether the height-IQ correlation plays significant role as a confounder in the study above.

<comment><USER11> But the numbers you describe are for adult height, right? Wouldn't you expect a much stronger effect if your sample was a mix of (say) 4-6th-grade kids. I think that's what GP is saying.

<comment><USER22> No, this is also found in children. See e.g. this[1] study, which also by design (it's a twin study) rules out the hypothesis that the effect is mostly environmental.

[1] - [https://www.ncbi.nlm.nih.gov/pubmed/17081263](https://www.ncbi.nlm.nih.gov/pubmed/17081263)

<comment><USER11> Thanks. That there is signal in which twin is taller at precisely age 12 is interesting, and seems like the same phenomenon as the adult effects.

But I'm saying something much simpler. In a school class, there's another effect, that the oldest may be a year or more older than the youngest. The mix of ages in a classroom will produce a correlation all by itself. It seems to me this would be a much bigger effect: 7th-graders are quite a bit taller, and better on tests, than 6th-graders.

<comment><USER22> Ah, that's a good point. It would probably require looking deeper into the studies to see how it is controlled for, if at all.

</comment></comment></comment></comment></comment></comment><comment><USER23> If somebody pays for something, they want to see the results. If the effects are local, you see with your eyes and you hear things second hand; a kind of soft feedback. If the effects are far away, you probably want to see a hard number, because you don't get the same kind of soft feedback.

Is the number (teacher score) useful? Maybe not. But you can't simply take away a number, resulting in no feedback. You have to either come up with a new number that is useful, or localize it enough that people can see the results. Otherwise people won't want to pay.

That's why these weird bureaucratic numbers usually come from state or federal requirements. People see the big pile of money going somewhere and they want "accountability" because they can't see the results for themselves.

Let's stop shuffling around so much money, laundering it through state and federal agencies. The money, if it comes back, always comes with strings attached. This goes for schools, highway funds, and many other things.

</comment><comment><USER14> My son started kindergarten this year, and unfortunately we are zoned into one of the worst schools in the district. He's a bright kid, already knows everything they would teach him, so we weren't concerned about academics, but let me tell you—his behavior at home, and especially his language use, has taken a really troubling turn. He is obviously picking up the behavior of some of the children he goes to school with.

I read a book not too long ago entitled "The Nurture Assumption," by Judith Harris. It influenced me more than anything I've read as a parent, because it is so obviously true. Her thesis is that everyone assumes that adults have a significant impact on a child's future, yet there is basically zero evidence to support such an assumption.

Peer groups are the dominant influence on a child's personality and development, full stop. This is probably hard for educators to accept because there's really nothing that can be done about it from their perspective.

<comment><USER24> I don't understand why people often want to reduce something to only one factor that explains everything . When I look back at my childhood I was influenced positively and negatively by my parents, siblings, teachers, my peers, neighbors and a lot of other people. They all had an influence at times that deeply impacted my life.

<comment><USER14> There's a difference between "one factor that explains everything" and a dominant factor that explains most of the variation.

<comment><USER24> I just doubt that in many cases there is a dominant factor that explains most but I think that instead there are often several factors of more or less equal importance. We made that mistake already in nutrition ("fat is the main problem") and it caused decades of problems. The proportion of these factors is also highly individual.

<comment><USER25> Why do you believe that it's more likely for several factors to have roughly equal importance than for one factor to be the most important?

As an aside, the mistake in nutrition was simply that it wasn't true. And it also wasn't a "mistake," it was a lie that the sugar industry paid to spread.

<comment><USER26> >Why do you believe that it's more likely for several factors to have roughly equal importance than for one factor to be the most important?

if you pick n numbers at random, it's not likely that one of them is bigger than the half of their sum.

<comment><USER27> That _really_ depends on the distribution of said numbers. You're probably assuming uniform distribution, but there are power law distributions like wealth where the 26 richest people own as much as the bottom 3.8 billion combined.

<comment><USER26> to be honest, I don't know much about probability.

but my intuition says that if you pick all variables from the same distribution, this should still hold.

At first, we don't know anything about the factors, so they are assigned a random importance. or am I missing something?

</comment></comment></comment></comment></comment></comment></comment></comment><comment><USER28> Hypothesis: Teachers, _individually,_ don't have statistically measurable effects. Students in a given cohort are mostly identical, and are mostly exposed to identical environments, such that influences on them average to some mean. As a result, minor influences, as long as they act reasonably consistently, are elevated to statistical significance.

<comment><USER4> On average, it would be true, meaning most teachers do not have significantly different effect on most students. However, there are always particularly good and bad teachers.

</comment></comment><comment><USER29> I'd strongly question our ability to measure educational outcomes. If they're basing that on standardised testing, then I'd argue that pretty much invalidates any conclusions of the research.

<comment><USER30> Do you think it's inherently impossible to measure educational outcomes or just difficult with the tools that we today?

<comment><USER29> I think it's very difficult to come up with accurate objective measurement methods (nobody's done it well yet). The best assessments tend to be subjective teacher-based assessments (for similar reasons as to why hiring tends to be done by subjective personal assessment - it's hard if not impossible to define the criteria for "good" upfront. Someone may approach things in a completely different way that nobody had thought to measure). And this is before you get into the biases of the people drawing up the assessment criteria etc.

</comment></comment></comment><comment><USER31> It seems to be universal that basing people's career progression on metrics is harmful. People try to do this with engineers as a substitute for understanding what's happening on the ground and having an actual relationship. At best, metrics can raise a flag for you to ask empowering questions.

</comment><comment><USER32> This is also the tale relevant to most A/B testing.

</comment><comment><USER33> Ruling out teacher impact on height without testing is perhaps not strictly scientific?

We really don't know what is true unless we test it. I know it sounds ridiculous but it's not beyond the realms of possibility that teacher opinion of student capabilities influences social status which in turn influences release of growth hormones which influence height. Aren't there other species which grow when they rise to the top of the pack as growth hormones are released to assist in maintaining that status? Not saying it's likely but if left untested we cannot rule that out. There have been plenty of surprises in science when we went and actually tested what we previously presumed to be implausible.

<comment><USER34> Or perhaps good teachers are also better at getting social services to poor students, so they can get food stamps, eat better, and grow talller?

[https://xhxhxhx.tumblr.com/post/189336550187/teacher- effects...](https://xhxhxhx.tumblr.com/post/189336550187/teacher-effects-on- student-achievement-and-height)

</comment></comment><comment><USER35> "When a measure becomes a target, it ceases to be a good measure." \- Goodhart's Law

</comment><comment><USER36> I know a brilliant junior school teacher teaching years 1 to 3.

He constantly configures his classroom to maximise learning continuity for the entire class. It is a massive challenge balancing out the problems students face physically or outside the classroom. Teaching has become the easy part of teaching.

The problem with student learning is that is affected by three things.

Emotional Health Physical Health Teaching Quality

to build an educated adult you need to optimise all three variables.

The problem with rewarding teachers is that their students aren't objectively assessed on all three dimensions.

In every district in the world there should be three person educational assessment teams that consist of an emotional health assessor, a physical health assessor and an academic progress assessor that work as a team to objectively assess the students and work with the teacher and support agencies to eliminate learning barriers.

Any students that need help should get referred to the correct service or program as quickly as possible. The teacher should focus purely on teaching and integrating support agencies.

Teachers deserve to be rewarded for their teaching ability in an objective way. As it happens there is a lot of unnecessary subjectivity and people blame teachers for not being social workers, counsellors and doctors. The education of every child in a class deteriorates as these three dimensions become less homogenous because the maximised learning continuity of the group depends on a limited resource. It is teachers who can creatively balance them while engagingly delivering the curriculum that are creating unrewarded alpha in the educational space.

Paying $250,000 a year in salary to a group of 3 specialist objective assessors with the data linked to the health and social services would get a better return on investment than any other expenditure a government could make in lifting the health, education and future earning potential of children.

If a child isn't learning there is always a reason. The faster you address that reason the more value you create. Sometimes it's the teacher, sometimes it isn't but for the child's sake we should definitely diagnose the reason.

</comment><comment><USER37> There's a significant positive correlation between height and IQ: [https://en.wikipedia.org/wiki/Height_and_intelligence](https://en.wikipedia.org/wiki/Height_and_intelligence)

There's also a correlation between IQ and academic achievement.

So, if we did decide for some (undoubtedly bad) reason to reward teachers for happening to have more than average tall students it would be comparable to rewarding them for having more than average high achieving students.

</comment><comment><USER38> Anyone who has done A/B testing knows that you need tens of thousands of data points to pick up any causal relationship unless it's a huge effect like the retention impact of telling your customers to lick a donkey's balls. No way you could pick it up for a teacher with 30 kids a year except over that teachers entire career.

</comment><comment><USER39> > 1 Introduction

> The increased availability of data linking students to teachers has made it > possible to estimate the contribution teachers make to student achievement.

There was some data available before (or the sentence would not have used the word "increased"). Why wasn't it possible to estimate with that?

> By nearly all accounts, this contribution is large.

It goes on to talk about what "large" means:

> Estimates of the impact of a one standard deviation (σ) increase in teacher > "value-added" on math and reading achievement typically range from 0.10 to > 0.30σ, which suggest that a student assigned to a more effective teacher > will experience nearly a year's more learning than a student assigned to an > less effective teacher (Hanushek & Rivkin 2010;...).

(Typo: "an less effective" should be "a less effective".)

A "range from 0.10 to 0.30σ" doesn't make sense. A Greek lowercase sigma (σ) is used to represent one standard deviation, but the sigma is used only on the upper end of the range. Should it have been from 0.10σ to 0.30σ?

And how are they measuring the impact on achievement of an increase in teacher "value-added", anyway? It says that estimates of the impact "typically range from 0.10 to 0.30σ", but it doesn't say what units those figures are in.

The sentence goes on to say that those unit-less estimates "suggest" that "a student assigned to a more effective teacher will experience nearly a year's more learning than a student assigned to an less effective teacher". Over what time period? That is, how long does a student have to study under a "more effective teacher" to get "a year's more learning"? 1 week? 12 years? It doesn't say.

And finally, how do those unit-less estimates "suggest" an impact measured in learning time? It doesn't say.

<comment><USER40> You are being absurdly pedantic. For example

>A "range from 0.10 to 0.30σ" doesn't make sense.

Out loud, you might read it as "oh point one to oh point three sigma." And it's fine. Ever written a phrase like "it's very expensive, costing somewhere around $3-4M" with one "$" and one "M" but two numbers?

</comment></comment><comment><USER41> Can't econonomists learn LaTeX? The typesetting is so horrible its putting you off from reading it...

</comment><comment><USER42> I think the message to parents is loud and clear: send your kids to the teacher that will make them tallest.

<comment><USER43> You have made me laugh dear sir or ma'am! :P

</comment></comment><comment><USER44> Research done more than 20 years ago (and repeated and confirmed) already found that teachers have very little effect on educational outcomes. The biggest correlative factor is socioeconomic status and education level of the parents. Everything else is hit or miss

But hey, let's publish a pointless paper... because academia.

<comment><USER45> I think this is an important paper. Even or especially if it confirms other studies. When I was a teacher in inner city San Bernardino, we were held accountable for student achievement ignoring student ability, socioeconomic situation, home life, or their capacity to disrupt the class. In large part, this is because of studies that say a teacher has outsized effect on student test scores. Now, I think a special kind of person can connect better with some kids and help them achieve. I think that is not something you can mass produce. With more studies showing teachers are not as critical as schools want to believe, maybe we can start focusing on other metrics to gauge suçcess.

<comment><USER46> > With more studies showing teachers are not as critical as schools want to > believe, maybe we can start focusing on other metrics to gauge suçcess.

Like cost of hiring? Seriously, if teachers are not as critical, why not hire less or pay less salary... any half decent person in the classroom will do.

I think the study is about right that teachers are not as critical as they'd like to believe. I just don't know what to think of the implications...

<comment><USER45> I still think a bad teacher is absolutely terrible and that teaching is not easy. I don't look at teacher salaries and think they are too high at all. I think we are bad at measuring what makes a good teacher. I just know it is not based on standardized test scores.

When I was a teacher, I had zero power to remove a disruptive or inattentive student from my class. I had 9th graders who could not deal with negative numbers being expected to do well on state Algebra tests that are of arguable quality. Even if they made substantial progress, they would not be to grade level.

I can still remember one student who after nearly a year of not being bothered to pay any shred of attention in class, during the final review, paid enough attention during the last steps of solving an equation: Me: Alright, and combining like terms, what is 10x - 18x? Student, suddenly paying attention: But wait, you can't subtract a bigger number from a smaller number!

I can't stop the class on nearly the last week of 9th grade algebra to help this student understand negative numbers. And they are not interested in coming in to get help outside of normal class. Parents were not interested in making sure this kid got through school.

Not so fun fact: at this school, less than 4% would go onto any post-secondary education. Of them, about 2% would go on to finish a degree. Something like a 90% transitory rate (meaning that most students who started 9th grade at this school would transfer to a different school before graduation, if they made it that far). I could go on, but there was an underlying cultural issue that did not value education. That trend is hard to buck: I had third generation gang members, kids raising their siblings because parents (often a single parent) were working multiple jobs, kids dealing with daily violence, one kid was stabbed to death right off of campus. The majority of these kids and their families have no experience seeing what an education can do for their prospects. Add onto that a tough employment market (inner city San Bernardio!), and those who did have siblings who did get a degree, they often couldn't find a job.

All this to say, I don't think lowering salary of teachers would help. Maybe lowering the cost of administrators would help. At this same time, there were more administrative personnel in the district than teachers, something I could never understand.

</comment></comment></comment></comment><comment><USER47> What if bad students get hit on the head thus decreasing their height?

<comment><USER48> Please don't do this here.</comment></comment>


Simple Way to Lower Your Energy Bill Using "Granola" - <AUTHOR> http://www.unfinishedman.com/lower-your-computers-energy-bill-with-granola-personal/

<comment><USER3> TLDR: someone's trying to sell their version of cpufreq_ondemand to people who don't realise it's built in to the OS.

If anyone's wondering how they got their 30% power saved figure: their method for measuring power consumption without Granola starts "Set the operating system power settings to the High profile in the Power Options"[1] - <USER2> windows, which I'm guessing is going to disable the built-in frequency governor. Not exactly a fair comparison. They don't benchmark granola against ondemand on linux. Can't imagine why.

[1] <http://grano.la/software/benchmark.php>

<comment><AUTHOR> They are selling a corporate version, it's true. For home users it's free, though.</comment></comment>


Ask HN: Is there a good CMS for websites like kickass.to and such? - <AUTHOR> The past few days i've been looking for a CMS for torrent websites for a private project of mine (nothing illegal) But i can't seem to find any good ones! <comment><USER2> Gazelle is a pretty popular one, powers what.cd and a few other private trackers: [http://whatcd.github.io/Gazelle/](http://whatcd.github.io/Gazelle/)

<comment><AUTHOR> It's got a pretty outdated UI. I was looking for something like kickass</comment></comment>


Ask HN: What typefaces and display technologies were used in the Apollo MOCR? - <AUTHOR> I am trying to locate any photographic or documental evidence on the Apollo-era Mission Control consoles (in particular, the slow-scan TVs). So far, as I understand, the displays show images captured from cameras, with overlays on top of CRTs where computers (AFAIK, from the RTCC) generated the variable data. Some pictures show what looks like character cell based displays (with a grid of monospaced characters) and some display things that look like vector displays. I couldn't find anything that would clearly indicate raster character based displays (reverse video would be one such cell attribute that's exceedingly hard to do with vector displays).
The purpose is to recreate those fonts, like I did for the IBM 3270 terminals (https://github.com/rbanffy/3270font)
I even tried Stack Exchange (https://space.stackexchange.com/questions/41048/are-there-any-close-up-photos-of-the-screens-used-in-the-mocr2-from-the-apollo-e?noredirect=1) with some limited success (the movies are very interesting)
Is there anyone here who was involved in the MOCR/RTCC operation (or at the recent restoration) that could shed some light into this? <comment><USER2> This is a wonderful undertaking! I don't have anything super substantive or helpful to say here other than I think it is super cool that you are doing this, and heartily encourage you.

<comment><AUTHOR> Thank you. I suspect it'll be an interesting trip down through ancient interactive/real-time computing, _if_ I manage to make any progress.</comment></comment>


Show HN: Markov-Avro-tools; build Markov chains out of many common sources - <AUTHOR> https://github.com/jacopofar/adium-to-avro <comment><AUTHOR> Wrong link, it was [https://github.com/jacopofar/markov-avro- tools](https://github.com/jacopofar/markov-avro-tools)

</comment><comment><USER2> What's up with all the green accounts in this thread.

</comment><comment><USER3> Why haven't you done it in ECMASCRIPT 6?

</comment><comment><USER4> JavaScript is turing complete

</comment><comment> mario-fusco Haskell or GTFO</comment>


Famous hacker suddenly finds himself infamous, in some quarters - <AUTHOR> http://www.sacbee.com/2010/06/13/2818601/famous-hacker-suddenly-finds-himself.html

<comment><USER2> While I disagree with what Lamo did, Manning is an idiot for bragging about what he did to anyone, and the "Russian roulette" argument is perhaps sound.

<comment><USER3> I'm tempted to agree with Lamo. It doesn't sound like Manning was thinking carefully about what information he released or why. He was just a lost soul who found a way to feel important and wield power against a system he felt trapped in. If he really had an agenda to expose U.S. wrongdoing or give Americans a better understanding of the nature of war and the consequences of projecting American power overseas, then I would be all behind him. If he was thinking that carefully, though, he wouldn't have needlessly incriminated himself to a near-stranger.

<comment><USER4> There is no doubt that Manning was stupid, but he's a 22 YO kid. Lamo made no attempt to talk the kid down: he just sold him out to a military that runs secret prisons, tortures, and claims the right to be able to assassinate its own citizens.

My guess is Lamo, despite his argument that there was morality behind what he did, sold the kid out to protect himself. Given Lamo's lax sentence for past crimes (6 months house arrest), I'd guess he made an agreement to inform in the future.

<comment><USER5> It isn't like Lamo sold out a fellow hacker; Manning had special access, and probably obtained the leaked information using that, rather than any particular skills.

That phone call to Lamo was tantamount to "Hi. You don't know me, but you're now an accessory to treason." Already convicted felon or not, nobody needs that kind of turd dropped right in the middle of their life.

<comment><USER6> I agree completely. Except for one thing: "Already convicted felon or not" makes it sound as if being convicted of felony A makes it _easier_ to handle being accused of felony B. But the opposite is the case.

Lamo could easily have been looking at a scenario where _he_ got far worse punishment than the actual perp. Getting a conviction against a known felon is so, so easy. It's not inconceivable that he would have ended up taking the fall. Just because it happens in spy novels doesn't mean it can't happen.

As for the ethics of turning Manning over to the tender mercies of the US Government: no matter what you may think of the ethics of commiting the particular crime that Manning is accused of, there are limits to how far down the cliff you should follow a suicidal person. When you get a _cold call_ from someone you _do not know_ to tell you about some serious Federal crimes, there are several possibilities. One is that the caller is the real thing. Another, far more likely, is that he's mentally ill or trying to punk or scam you. Yet another is that he's a government agent trying to entrap you. But one thing is for sure: there is nothing that you, the world, or the "hacker" community will lose by turning this guy in. He's obviously an order of magnitude too indiscreet to be a good spy, he's going to succeed in getting himself caught any second now, and the only question is whether you're going down with him.

</comment></comment></comment></comment></comment><comment><USER7> Am I the only one who finds the narrative of the article, namely the reclusive genius, shunning most worldly possessions, a little cliched?

<comment><USER8> you would have trouble finding someone who spends more time manicuring their public image. check the recent edits on the wikipedia article about him if you don't believe me.

<comment><USER9> the entire story breaking was based on this principle. he thought it would be best if he basically made a press statement via wired column through a friend who would say all the right things, a day before an official statement by the military. if anyone wants more examples they are not hard to find. now the story is actually about him and not the leaker in question. this kid should run for office.

</comment></comment></comment><comment><USER10> Boring prose. I couldn't make it to the end. Journalism should not try to engage readers at the expense of telling news. Where is the news in the first sentences?

<comment><USER11> Indeed. Very frustrating.

"Lamo is the most famous computer hacker in the world at the moment"

If he's so famous, then why have I never heard of him? Get to the point.

</comment></comment><comment><USER12> Not so interesting from a hacking perspective. He chat with a soldier and released information on his findings and now he's a famous hacker?

<comment><USER13> He didn't get the "famous hacker" label for this incident. See <http://en.wikipedia.org/wiki/Adrian_Lamo></comment></comment>


Ask HN: How does Google back up personal data? - <AUTHOR>

I'm wondering how Google backs up personal account data stored on their servers (ie, all Gmail messages and attachments, Gdocs files, etc). How do they insure that your data stored on their servers is safe and backed up?  What's the likelihood of losing all the data from your Google account? <comment><USER2> The last data loss incident that I'm aware of involving gmail was in 2006, when a bug in Firefox allowed a cross-site scripting attack to delete emails. See [http://www.oreillynet.com/xml/blog/2006/12/gmail_disaster_go...](http://www.oreillynet.com/xml/blog/2006/12/gmail_disaster_google_confirme.html) for some discussion of it. If anything more recent has happened, it didn't turn up in a Google search.

Keep in mind that only about 60 users lost emails in that incident. I believe the accounts were later restored from backup. And the cause of the data loss was outside of Google. I've never heard of Google itself losing any user data that was stored in gmail. Ever.

That said, there is a first for everything. Plus, very rarely, accounts can become temporarily unusable. (The data is safe, but temporarily inaccessible.) This usually fixes itself in a period of minutes to an hour. I would personally bet that the odds of your being unable to access your account because of a problem on Google are significantly lower than the odds of your being unable to access the internet because of a problem with your ISP. But if you are concerned, then by all means you can use IMAP to download all of your gmail data and back it up for yourself.

Note, I work at Google, but not on anything related to gmail. Nor do I personally know anyone on the gmail team. I only know about the incident above because I googled "gmail data loss" and it was the only story that turned up. I know something about how we backup data, but I'm not at liberty to discuss it. However I will say that I personally have great trust for Google's backup procedures.

</comment><comment><USER3> In general, don't expect Google to answer any questions about how they do things.

I suspect that they don't back up per se but instead replicate data across multiple data centers.

</comment><comment><USER4> I've never worked for Google, but I understand from reading that BigTable is a storage service that includes replication.

Here's an interesting post about AppEngine which I expect applies to gmail. gdocs etc...

[http://googleappengine.blogspot.com/2009/09/migration-to- bet...](http://googleappengine.blogspot.com/2009/09/migration-to-better- datastore.html)</comment>


Forget Socialism versus Capitalism. Here's the Real Debate We Should Be Having - <AUTHOR> https://www.barrons.com/articles/forget-socialism-versus-capitalism-heres-the-real-debate-we-should-be-having-51550835040 <comment><USER2> I can't help but think about the decline of the church and the role that it played in supporting morality and social cohesion. Obviously the church is not the only or even the primary source thereof, but in America it was a very prominent source.

</comment><comment><USER3> I'm disgusted and not at all surprised that you can pay to get a better prison cell in some US cities.

<comment><USER4> To be fair, you could do that in 18th century Britain also.

</comment></comment><comment><USER5> "with rising economic inequality, declining social mobility, and accelerating climate change."

I'm always puzzled when someones wishes the US were more of a socialist country.

You really do have more economic inequality in socialist countries. The top wage earners (and at some point, all wage earners) are taxed at much a higher rate, which reduces overall wages.

We should be funding education programs to help people gain the skills to get out of poverty. Not giving them a handout, which is only temporary.

Climate change will only be solved with better technology, which if history is any example, will come from the private sector.

"So policies that are meant to encourage civic-minded use (car pooling) of a public resource (roads) are instead turned into a fee-for-service opportunity for well-to-do commuters to get to work faster"

I think this is a great idea. If you want to get to your destination faster, you pay for it. In a sense, it's a usage tax.</comment>


Take-Two Interactive's Kerbal Space Program has a new restrictive EULA - <AUTHOR> https://www.take2games.com/eula/ <comment><AUTHOR> Official announcement by Take-Two on Steam: [https://steamcommunity.com/games/220200/announcements/detail...](https://steamcommunity.com/games/220200/announcements/detail/1673522003721086842)</comment>


Babili: An ES6+ aware minifier based on Babel - <AUTHOR> http://babeljs.io/blog/2016/08/30/babili?exports=guy <comment><USER2> It may just be a paranoid delusion, but I'm worried that Babel is trying to become a more encompassing build tool ala Grunt/Gulp instead of just transpiling. I love Babel and plan to continue to use it in the future for my front-end development, but the "doing it all ourselves" is a little bit much.

I would much rather see a recommendation and efforts around Uglify than a brand new minimization tool, and I would rather see work on acorn[1] rather than around a new parser[2], because these things fragment the community rather than bring them together.

Edit: Yes, Uglify has taken a long time to get work done on ES2015, but note that the spec has changed a lot over that time. It does feel like they are dragging their feet or not getting much done in that front, but all the more reason to put one of the Babel devs who may have more free time on the project to get more things going.

1: [https://github.com/marijnh/acorn](https://github.com/marijnh/acorn)

2: [https://github.com/babel/babylon](https://github.com/babel/babylon)

<comment><USER3> We're not losing focus. Babel is as focused as ever on being a general purpose parser, transformer, and code generator. Babili is a set of Babel transforms.

Uglify has its own parser and transformer and generator, so arguably any work that goes into that is duplicate work because Babel already covers most of what it does.

Re parsers: we had to fork acorn because they were understandably skeptical of adding all the experimental and non-standard features (JSX and flow types) that Babel supports.

I started this project at Facebook and one of our aims (which is mentioned in the post) was to have access to the original source AST which may include Flow type annotations, JSX and early ES proposal features. Have I spent the time trying to get those into uglify, the majority of the work would've went into parsing and code generation. And I would imagine an uphill battle with the maintainers convincing them of adding non-standard features.

<comment><USER2> > Uglify has its own parser and transformer and generator, so arguably any > work that goes into that is duplicate work because Babel already covers most > of what it does.

That seems a little hubristic... Not everyone uses Babel, and working with the Uglify devs to get it ES2015+ compliant (through whatever means, including adding a different AST parser) would make the entire community better, not just Babel. Since not all browsers support ES2015, I have to use babel, but if I didn't need to use Babel, I wouldn't. But now I'm kind of forced to for uglification now until ES2015 support comes to Uglify.

> Re parsers: we had to fork acorn because they were understandably skeptical > of adding all the experimental and non-standard features (JSX and flow > types) that Babel supports.

JSX and Flow are not part of ES spec. I can understand those being in a different parser, but that's a flimsy argument for creating a whole new parser. If you had to create a brand new parser to handle this, it seems like a Babel issue, not a parser issue.

<comment><USER4> Not sure why you're being down voted, your comment is fine I think.

What's worse than having specific parsers, transformers, and generators – I think – is not having an AST standard. If there was a common standard for ES ASTs, including extension points, then it becomes a lot easier to write tools that aren't specific to a tool chain but specific to a data structure. I could use the Babylon parser, but do transforms with Rollup and optimizations with Uglify (obviously provided those tools had APIs that take/return ASTs.)

As it stands, there's a varying degree of lock-in when using these tools, making them more difficult to compose. That's a shame I think.

<comment><USER2> You're right -- it would be nice to have a standard AST for ES, which is what you have in languages like Python, so that tools can be built around it more easily and without lock-in. This would also help accomplish my idea of helping the community rather than one tech specifically. I saw some other comment that mentioned ESTree but I guess that didn't go anywhere... sucks.

</comment></comment></comment></comment></comment><comment><USER5> There is currently a discussion going on about changing the name back to babel-minify (you can vote)

[https://github.com/babel/babili/issues/124](https://github.com/babel/babili/issues/124)

</comment><comment><USER6> Competition is great. The more minifiers the better.

At a usability level, babili has a 33M install footprint and must be installed locally in the directory in which you intend to use it.

uglify-js can be installed globally and has a 1.9M install size.

And I've never understood how to configure babel's preset and plugin files. Why is it necessary for a minifier to do this? Surely this can be greatly simplified.

<comment><USER7> Long live Babel 5.8!

firstname.lastname@example.com is faster than babel 6+, can be installed globally and works out of the box. It just... you know, does what versions 1, 2, 3 & 4 did: compile ES2015 into ES5. So I just use that. Not every project is a "node" project that is already dumping megabytes of dependencies into the project directory. I don't want to have to buy into an entire ecosystem just to use one tool—a shim, at that.

<comment><USER8> I gave up and wrote my own babel cli front end (sudo npm install -g better- babel-cli) for that very reason.

babel --es2015 --babeli infile.js -o outfile.js.

</comment></comment></comment><comment><USER9> Interesting, but the only 'Pro' I can actually see here is ES6 support when you were previously using uglify. I think using Closure Compiler on TypeScript output with the right JSDoc comments can yield much better results as there is much more information the minifier can work with.

<comment><USER3> One of our future plans is to use type annotations (Flow, but maybe typescript too) to do advanced optimozations.

</comment></comment><comment><USER10> Can this yield smaller bundles?

<comment><USER11> I've been seeing incredibly compressible output from Typescript, if that helps any. If what you mean by 'bundle' are these 'webpack' things that include css and images, and all that. Smaller bundle to me would be not to use one at all.

It doesn't seem like webpack's chief concern is file size or simplicity. So if yours is, just don't use it.

<comment><USER10> What has this to do with TypeScript?

<comment><USER6> Can babili or babel parse TS?

<comment><USER12> Babel can parse Flow, which is similar to Typescript. However, Babel doesn't have any built-in support for inferring or analyzing flow types. However, some of this type information might be useful in building a more advanced closure- like minifier.

</comment></comment></comment></comment></comment><comment><USER13> You don't need Babel or a build process to minify ES6. Pretty Diff has supported this for years [http://prettydiff.com/?m=minify](http://prettydiff.com/?m=minify)

<comment><USER14> That doesn't appear to replace variable names with shorter versions, or remove dead code, which Uglify and other minifiers do.

</comment></comment><comment><USER15> Ah, are they going to make a minifier based on Bublé ([https://buble.surge.sh/](https://buble.surge.sh/)), too? Perhaps they could call it Bublili.

<comment><USER16> coming soon... [https://prosecco.surge.sh/](https://prosecco.surge.sh/)</comment></comment>


Fossil: Distributed Revision Control, Wiki, and Bug-Tracking - <AUTHOR> http://fossil-scm.hwaci.com/index.html/doc/tip/www/index.wiki

<comment><AUTHOR> This is by the creator of SQLite.

It is its own distributed SCM which does seem a bit silly given that there are already some very good ones out there. I.e., I'd much rather see this work with Mercurial and Git rather than competing with them.</comment>


The Cathedral and the Pirate - <AUTHOR> http://www.artima.com/weblogs/viewpost.jsp?thread=262565

<comment><USER3> This is Steve Gillmor-class word salad. Microsoft is alternatively described as a ship, a water buffalo, a cathedral construction crew, something that guards a basket, a monarchy, and a net hanging in the jungle. The various metaphors try to fight it out, but they don't have a chance amidst all the cliche and jargon.

This level of inattention to language makes me think that not many neurons were fired during the writing of the article, and prejudices me against what might be a perfectly valid point, if I could find it.

<comment><USER4> Not only is it incomprehensible, it's factually inaccurate. According to Eckel, IE came along _after_ Google, which is funny considering Microsoft got sued for _bundling_ IE before Google was even incorporated.

<comment><USER5> He also asserts that IE started the browser wars. As I recall, there was competition from the very beginning, with Netscape Navigator battling with NCSA mosaic. And even upon the advent of IE, you've got to turn your sites toward AOL as well.

</comment></comment></comment><comment><USER6> It's amazing how much commentary there has been about a piece of vaporware that is over a year from release (at least). Oh, I'm sure Google will release it, but there is so little known about the final architecture that it is almost impossible to speculate intelligently about it.

And does anyone see the parallel with the Java Network Appliances that were going to be "the next big thing" at the end of the 90's? Certainly, we live in a much more connected world today, but to pretend that nothing of value is done on PCs except opening up a browser is a bit of a blindered view, IMO. Oh well, it's all just speculation until there's a product..

<comment><USER7> Right and if I read one more article about how no one can do anything on a netbook with their paltry 1.7 gig Atoms I am gonna spew.

I am running a stable of happy 900 mhz machines for my bread and butter work.

<comment><USER8> When I look back on the years [most of the 70's] I spent programming 16K x 18-bit single-digit megaherz machines, with single-digit megabyte hard disks (although they _were_ head-per-track, which makes them _much_ faster - <USER2> to lousy SSD's), and what I was able to get done on them, I laugh....

</comment></comment></comment><comment><USER9> I am running Windows 7 on a SSD right now. While most of the author's points aren't based on the assertion that this is impossible, such a poorly researched argument makes it hard to take the rest of the article seriously.

<comment><USER10> What is the size of the SSD? If it's a desktop-sized (60GB+) SSD, then I don't think it applies; the author's argument is that it won't fit on the tiny netbook SSDs. Obviously, within a little while that will be wrong as well.

</comment></comment><comment><USER11> I think the section "MGBs, TANKS, AND BATMOBILES" from Stephenson's In the Beginning was the Command Line was a much better analogy, despite it being a slightly different, but related, topic. That whole intro analogy bit could have been skipped without losing anything.

</comment><comment><USER12> _Microsoft could have taken .NET and created a thin layer of glue onto the hardware, and come up with a really good, robust, and revolutionary OS_

... That ran only on one exact hardware configuration.

<comment><USER13> Not necessarily: consider Windows and then take out everything that doesn't belong to the lowest level kernel and essential driver services. Now, build the .NET API on top of that core and not on top of the Win32 API.

There you have it. A non-Windows OS built with Microsoft technology.

Microsoft will never do that as it would sacrifice sales of its Windows line and their VPs just can't sacrifice their bonuses.

<comment><USER14> More likely they won't do it because it would mean that everything made for Win32 would not run on the new platform. This includes all programs made with various other libraries (MFC, WTL, QT, Fox, etc) that "plug into" Win32. Hence they'd have vastly fewer application that would run on this new OS, and people trying it out would complain that "this version of windows breaks my applications".

On the other hand it would be interesting (Singularity comes to mind), but they'd have to call it something other than Windows.

<comment><USER13> They can avoid program breakage by emulation, much like Apple did with early releases of OSX.

</comment></comment></comment></comment><comment><USER15> Microsoft will, of course, offer a similar product based on IE + Bing + Live. The only real loser here are the PC OEMs. In 2 years they'll be reminiscing about the good ole' days of high margin netbooks.

<comment><USER16> Similar? Only on paper. Sure it will be designed to meet a bullet-point list of formal features compiled by an Analyst, but those won't matter much in the end.

It will not have the appeal nor the ability to interconnect with standard- abiding software from ISVs from all over the world the Google offering does right now. Carpet-bombing style marketing won't help much.

</comment></comment><comment><USER17> "Windows is an enormous collection of design mistakes that work well enough to get by."

Don't forget, Windows was ripped of of the Mac, so....

</comment><comment><USER18> Really, this is one of the very few article on GCOS that actually make sense (or at least tries to). So far, most of the coverage has been "ZOMG!!1! SHINYCOOL NEW!!1!".

Although I still don't think GCOS will take over the world. It's going to be an OS for the clueless. I'm pretty sure most geeks would rather use a regular Linux distro than a stripped-down web-centric OS that has Google's branding everywhere.</comment>


If you live each day as your last... - <AUTHOR> http://howidothings.blogspot.com/2008/02/if-you-live-each-day-as-your-last.html

<comment><USER2> Why, praytell, was this even submitted?</comment>


Facebook Stares Down Labels Over Project Playlist Takedown Demand - <AUTHOR> http://www.techcrunch.com/2008/12/19/facebook-stares-down-labels-over-project-playlist-takedown-demand/ <comment><USER2> That's an interesting move. The DMCA offers a wonderful save haven for companies who allow users to post content, but that safe haven is eliminated upon refusal to act on a takedown notice like this. The article says, "It's not clear Facebook is fully aware of what they're stepping into". I'm shocked that they would risk being found liable for these user actions because they didn't act on the takedown notice. For a company struggling to find funding, now is not the time to make a stand that could bankrupt them.

/This is not a commentary supporting the DMCA or US copyright law, merely a commentary on the legal risk Facebook might be contending with here.

</comment><comment><AUTHOR> facebook is not the infringing party and has no liability nor obligation to comply with any takedown notice.</comment>


Nasa Study: Mass Gains of Antarctic Ice Sheet Greater Than Losses - <AUTHOR> https://www.nasa.gov/feature/goddard/nasa-study-mass-gains-of-antarctic-ice-sheet-greater-than-losses <comment><AUTHOR> Oops, looks like it's 3.5 years old. Sorry, an old story. (But still interesting.)

<comment><USER2> It's some old good news, but 2018 or 2019. Results would be really interesting.</comment></comment>


Docker Goes native on non-Linux OS with latest beta - <AUTHOR> http://www.releasemanagement.org/2016/04/docker-goes-native-on-mac-and-windows-with-latest-beta/ <comment><USER2> So "native" means "not VirtualBox" now? Docker for Mac might be a significant step forward compared to the previous solutions, but it still involves a Linux VM. I guess you could say that xhyve is a native hypervisor, but that's a bit weaselly.

</comment><comment><USER3> I'm confused. Why is this hailed as a private beta? The binaries are there for everyone to download ... [https://github.com/docker/docker/releases](https://github.com/docker/docker/releases) for the client & [https://master.dockerproject.org/](https://master.dockerproject.org/) for the master

<comment><USER4> The Docker for Mac + Windows native clients are currently in private beta. They are both separate applications from the main Docker project.</comment></comment>


Ask HN: what software you use to create UML's? - <AUTHOR>

Hi,
I'm currently with AgroUML, but it's still needs a lot of work :/. I'm working with my team remotely so important for me is easy sharing options with my teammates.
What do you use for remote work? <comment><USER2> Visual Paradigm -

* It's cross platform (I use it at work on PC and home on a Mac).

* The pricing is very fair, particularly the single-user edition ($70).

* The community and viewer editions are free.

* It has nice support for automatically aligning/formatting/reorganizing diagrams.

On the downside the toolbar isn't that great, many common operations are in the main or context menus. Also the diagram explorer doesn't support subfolders for grouping things together.

<http://www.visual-paradigm.com>

</comment><comment><USER3> staruml - <http://staruml.sourceforge.net> on windows.

just in case, you are using eclipse/netbeans, they have decent modelling capabilities.

</comment><comment><USER4> I've found ArgoUML to be quite hard to work with. BoUML is much better.</comment>


Python internals: how callables work - <AUTHOR> http://eli.thegreenplace.net/2012/03/23/python-internals-how-callables-work/ <comment><USER2> People who find this stuff interesting should also check out Larry Hasting's talk "Stepping through CPython" from this years PyCon: <http://www.youtube.com/watch?v=XGF3Qu4dUqk>

<comment><USER3> I was at that talk. Having not done much C since college 6 or 7 years ago and only really starting Python about 3 months ago, it was very approachable and I got a lot out of it. I highly recommend it.</comment></comment>


Greaseless ball bearings: A revolutionary spin - <AUTHOR> http://www.gizmag.com/greaseless-ball-bearings-coo-space-adb/37689/

<comment><USER2> Previous HN discussion: [https://news.ycombinator.com/item?id=9588547](https://news.ycombinator.com/item?id=9588547)

<comment><USER3> Previous HN with no discussion: [https://news.ycombinator.com/item?id=9575968](https://news.ycombinator.com/item?id=9575968)

</comment></comment><comment><USER4> This may limit the bearing's lifetime.

If everything else is done right (bearing mounted correctly, lubricated, no dirt, correct loading, etc.), bearings ultimately fail due to high cycle fatigue at the rolling element tracks on the races. Repeated flexing caused by high Hertzian (contact) stress between ball and race makes tiny divots fracture out of the race surface. Particle count goes up, more divots break out...bearing fails.

The grooves they put in the races of these bearings will act as stress concentrators and accelerate fatigue failure compared to ungrooved bearings. Still, if low friction is more important in the application than long life, this may be a useful new twist on rolling element bearings.

</comment><comment><USER5> In a greased bearing the problem is that the balls can touch each other (causing sliding friction) and /or pack together on one side of the race causing uneven load or the inner race to shift relative to the outer. The solution is typically to put a cage in so they stay evenly spaced. This cage can be metal or plastic and the balls can rub against it. The grease is mostly used to lubricate the cage from the balls. The rolling resistance of the balls on the race is very low as they aren't sliding across the race, but _are_ creating friction and wear when they touch the cage.

This system seems to work by allowing the bearings that are packed together to touch briefly as they enter the divot causing them to space out afterward. I guess it would perform similarly to an un-greased geared roller bearing?

I'm not sure if this will work well under load. Grease provides lubrication to prevent pressure welding of the bearing to the race and it can also act as a heat sink. Besides those, I would assume the main problem would be fatigue at the site of the divot.

Still I think this is very clever.

</comment><comment><USER6> So it acts like a stop sign—it slows traffic down, and then more evenly spreads it out. Neat.

</comment><comment><USER7> The best part about all of this is if you follow the links to the Coo Space web site and then mouseover the links: their web site is hosted on, of all things, geocities.jp.

</comment><comment><USER8> I wonder how this works under load. If a vibrating or asymmetrical load is on the shaft (the normal condition for a bearing) then is the small deceleration/acceleration effect still working to separate the balls?

</comment><comment><USER9> Isn't another purpose of the grease to stop the ball bearings from rusting?

<comment><USER8> Don't they rust because of the water in the grease? So if the grease wears away, it leaves the bearing damp?

<comment><USER10> Water and grease are textbook immiscible things. There isn't water in grease. There may be water in the environment and there usually is in air, though.

<comment><USER8> Lithium grease is not resistant to water. And 'gear grease' has this composition according to Wikipedia:

"Gear greases consist of rosin oil, thickened with lime and mixed with mineral oil, with some percentage of water. "

</comment></comment></comment></comment><comment><USER11> If these truly experience "as little as 10 percent of the friction of a regular ball bearing", I wonder how they'll change skateboarding.

</comment><comment><USER12> Grease is needed to lubricate the balls so they are not in direct contact with the races. Without grease the balls/races will fail rapidly when under load. There is no _load_ on the cages so I fail to see how this development helps at all.

<comment><USER12> Thanks for the downvote. Obviously you do not agree with simple facts, but just in case you think I'm making my point up: [http://machinedesign.com/archive/proper-film-thickness- key-b...](http://machinedesign.com/archive/proper-film-thickness-key-bearing- survival)

Let me quote a key passage: "Engineers must check that films are sufficiently thick so asperities — peaks of surface roughness between mating surfaces — don't touch. Otherwise, bearings can rapidly wear and fail."</comment></comment>


Jaywalkers Under Surveillance in China Will Soon Be Punished via Text Messages - <AUTHOR> http://www.scmp.com/tech/china-tech/article/2138960/jaywalkers-under-surveillance-shenzhen-soon-be-punished-text <comment><USER2> The future is now I guess. Just wish it wasn't leading straight to a dystopian 1984 like world.</comment>


Top Uber Exec Emil Michael to Resign - <AUTHOR> https://www.axios.com/top-uber-exec-emil-michael-to-resign-2439849459.html <comment><USER2> On HN, there's no harm in waiting until a thing actually happens. It's not as if we lack for Uber threads.

</comment><comment><USER3> Reasons are given in the recode post linked within:

Michael, as Recode also reported, was also involved in an incident where an Uber executive he managed directly named Eric Alexander obtained the medical records of a rape victim in India. He also came under the spotlight when he suggested digging up dirt on journalists to a BuzzFeed editor in chief Ben Smith in 2014.</comment>


Most intelligent and deep thinking individuals out there fail to be happy - <AUTHOR> https://www.learning-mind.com/fail-to-be-happy-intelligent/ <comment><USER2> That's because they were not intelligent or deep thinking enough to follow the teachings of Epicurus.</comment>


Google wants to use its data to provide an new way of calculating inflation. - <AUTHOR> http://www.theregister.co.uk/2010/10/13/google_price_index/

<comment><USER2> I wonder how they'll get around the tech divide. For example: people don't sell gasoline online, but there are numerous websites that track that information. Also, any price index requires some decision over which goods are included in the basket. How would they determine this? How will they be able to determine the ratio of goods purchases online compared to those purchased offline? How will they overcome the "lowest price" problem that tends to come up (fortunately, for the consumer) when searches are done for products online. A simple average? A weighted average based on market share? How would that market share be determined?

Lots of unanswered technical details here. Still, it is another data point.

</comment><comment><USER3> Mostly duped, see: <http://news.ycombinator.com/item?id=1782681>

</comment><comment><USER4> This is a simple idea, but one which is probably quite hard to execute. Issues that spring to mind: identifying identical products (they may be named slightly differently, or be similar variations on a product - ipod w/ 8GB or 16 GB), web prices may often be different from in-store prices (e.g chains will price goods on a store-by-store basis), plus you got multiple prices for a product (big, small, 500ml, 250ml), old prices, new prices, discounted prices - and what about geographical location? Possibly hard to identify for some sites / merchants.

Interesting, none-the-less.

</comment><comment><USER5> Since about 40% of the CPI is housing, and that component is calculated in a way that reduces the volatility of CPI, and essentially ignored the entire housing bubble, then any alternative to government statistics is welcome. It is as if the Fed was driving a car using the oil pressure gauge as a speedometer.

There was a time when the cost of collecting economic statistics was prohibitive for all but a monopoly provider. Now that we are all beginning to walk around with smartphones in our pocket, we can look forward to using them as live economic indicators.

</comment><comment><USER6> Distilling inflation to a single number is hard even when you have all the prices available.

</comment><comment><USER7> Governments would never agree to this. For example, in the U.S., The CPI drives so many parts of the budget (inflation indexed bonds, Social Security payments, real GNP vs nominal GNP, etc.) that they would never give control of this to an external party [/conspiracytheory]

<comment><USER2> I'm not sure where you get the idea that the government needs to agree with something in order for it to be published. The CPI published by the Bureau of Labor Statistics is just one of quite a few price indexes, some of which are privately published.

</comment></comment><comment><USER8> I think it is very important for people to know that CPI is not inflation, it is not even a measure of inflation. At best-- and that is, if it were not so greatly "massaged", it would be a measure of the impact of trailing inflation on prices with the effect of productivity increases removed. But even that ignores international money flows.

Inflation is increase in the money supply. So the best measure was the money aggregates that the government used to publish. (Though I'm not sure how accurate they were.)

This may sound like semantics, but it is this constant under-reporting of inflation that is distorting the market. If you measure monetary inflation and work against that, a capitalist system is much more effective. By replacing "inflation" with "CPI" in people's minds, so many people have been led astray and many economic calculations come out wrong.

But this is beneficial for government that wants to print money to support deficit spending without limitation... and so they publish an essentially completely fabricated CPI number. then when you talk about inflation being %20, people say "LOL U Stupid. Inflation %1!!!!!"

To predict how prices will go, you project the likely increase in productivity over the next year and the amount of inflation over the last year... but even then, this is ignoring the massive holdings of dollars and treasuries overseas -- which really represent past inflation that whose effects we avoided via the bretton woods and other agreements. If confidence in the dollar continues to drop, those dollars will continue to come home to roost, goosing price changes even higher over the amount caused by the significant deficit spending (and consequent money printing that increases the money supply) minus relatively small increases in efficiency.

The noose around the dollar's neck is the accumulated decades of inflation that have been exported overseas. If it becomes untenable to continue holding them, then a selling panic will likely occur as nobody wants to be the last one holding the bag.

This is what happened with greece. The US is approaching greece in terms of debt levels and given that it appears the federal reserve is buying a large chunk of the treasuries at each auction (under the table, of course, as if this word got out it would immediately cause what I'm describing) the game can go on for only so long.

2008 was not the financial crisis. The financial crisis is in the dollar, which is the mother of all bubbles. I believe, that less than %10 of treasuries have a greater than a year, which means that %90 of the debt is being rolled over each year.</comment>


Remind HN: Followups are impossible if you have no contact details - <AUTHOR> One of the things I do on HN is look up previous discussions.  When doing so I deliberately keep my search terms open and under-specified, because in that way I regularly and frequently turn up related items that turn out to be of interest.
Many times I want to follow up on the discussion, to recount more up-to-date experiences, or to find out what happened so I can share in any discoveries made.  People so often learn things, and so rarely come back to share them.
But very few people have any contact details in their profiles.  I've not been gathering data explicitly, but this submission is prompted by the frustration of wanting to help, wanting to share my experiences and/or expertise, wanting to respond to a request for assistance, or wanting to find out how things turned out, and being unable to.
I know people are concerned about exposing email addresses, etc., but I get virtually no spam to the HN visible email address, and what little I get is more than out-weighed by the emails I get from the HN community.
Sometimes people think they have shared their address when in fact they haven't. The "email" field is not visible to others, it needs to be in the box of text.
Do you share your email?  Have you explicitly listed contact details in your profile? <comment><USER2> Reddit style reply notifications might be helpful. It's easy to miss a reply to ones own comments. Knowing this is true for others discourages revisiting an old discussion with new learning and insight, as it won't be seen by those involved in the original conversation, never mind a wider audience.

<comment><USER3> I understand that notifications could be helpful in some cases, but I actually like the fact that people don't get notified when someone replies to their comment, and I had assumed this was deliberate. It seems to make debates more objective. For example, if user A makes a statement, and then B disagrees, I like the fact that C can come along and backup A's points, rather than a defensive response from A. (Having notifications that were delayed by an hour or so might make for a good middle ground.)

<comment><USER4> My understanding is that it, no automatic notification of replies, is deliberate and the reason is to avoid stimulating flame wars. As someone who posts a lot and usually tries to avoid flame wars, the first thing I do on any site is turn off email notifications. If I care, I look at the threading of my comments.

<comment><USER5> Preventing 'flame wars' by making conversations more awkward and difficult to follow as time goes on just seems to create friction for everyone. And it doesn't prevent flame wars - people who are emotionally invested in an argument will follow a thread on their own accord. We've all seen them, i'm kind of ashamed to say i've participated in a few.

But, notifications could be opt in by default and opt out by choice, and they wouldn't necessarily have to be by email - you could be shown the last few replies to your comments in your account.

<comment> qu4z-2 Just to clarify terms here, "opt-in" means disabled by default, with user action needed to enable the feature. "opt-out" means on-by-default with the ability to disable it: exactly the situation you describe. At least, that's my understanding.

<comment><USER5> I may have misstated, then.. I meant that by default, you wouldn't get any notifications unless you chose to, and if you did, you could turn them off at any time.

</comment></comment></comment></comment></comment></comment><comment> zupa-hu I think an explanation next to all fields on the personal settings page would be great.

For example, when I first landed there, noprocrast just made me feel like an outsider. What the heck is that? Okay, english is not my mother-tongue, I didn't even know the word procrastination. Let's add some entrepreneur thinking: if I don't know what it means, nobody does! ^^

<comment><USER6> This is probably the best proposed, and least intrusive, solution to what may or may not be a problem.

</comment></comment><comment><USER7> It's probably not the sort of thing that should be formalized, yet I feel that HN could be bringing people together more than it currently does. I wonder what new things could be tried.

<comment><USER8> Adding a new profile field that says "contact email (optional)" seems like it might actually help a lot.

<comment><USER9> Or even just a check box to make the already-provided email public.

<comment><USER10> Agreed!

</comment></comment></comment></comment><comment><USER11> I've seen periodic rashes of emails from people with proposals or trying to promote stuff with generic emails I'm not even remotely interested in that I can trace back to my address being scraped from HN, this is a pity because it made me consider removing my contact details. I have no problem with personal approaches but the 'hustlers and growth hackers' can get on your nerves.

The large number of online and in-real-life friends I've made here ensured that it is still up and will stay up without any obfuscation or other gimmicks.

</comment><comment><USER12> Maybe HN needs a basic personal messaging system?

<comment><USER13> I'd like to see this as an alternative.

This post prompted me to add a contact email (obfuscated to hopefully guard against automated scraping), but we really shouldn't have to do this.

<comment><USER14> I have had a contact email for a very long time, but I haven't noticed any spam on it (gmail seems to have a great filter).

That said I have received a few emails that were the result of HN comments so I would strongly suggest adding one in.

</comment></comment></comment><comment><USER15> Yes, I had no idea the email field isn't publicly visible. Thanks for the heads up :)

<comment><USER16> Me, too. And I've been here twice as long!

</comment></comment><comment><USER17> Hijiking this thread, since mine got no traction...

What would also be great is if HN provided a field to add our public keys.

[https://news.ycombinator.com/item?id=9359536](https://news.ycombinator.com/item?id=9359536)

In the meantime, if you put a website in your profile, add your public key somewhere in there.

<comment><USER4> I've seen them in people's profile.

</comment></comment><comment><USER18> Would anyone be interested if I made "profiles and notifications" for HN ... and you could follow people or topics?

I registered the domain name [http://show.hn](http://show.hn) for just such an idea.

</comment><comment><USER19> > Many times I want to follow up on the discussion, to recount more up-to-date > experiences, or to find out what happened so I can share in any discoveries > made. People so often learn things, and so rarely come back to share them.

So: Blog your new experiences, submit them to HN, and (if this link is more relevant to HN than to readers hitting your blog otherwise) make a comment noting the relation to the previous HN discussion, with an appropriate link.

You don't need personal contact details to post a followup to a discussion on an open public forum.

</comment><comment><USER20> I provide one for introductions that winds up in my 'real' inbox. I've made one great contact through it so far and hope to make more as time goes on. No issues with spam.

</comment><comment><USER21> I share my contact details because I want to give people the ability to follow up with me privately on a submission or comment I made. HN is a wonderful community and I treasure its openness but sometimes you just want to be discreet about certain things. It's also a good way to prevent thread hijacking.

I'm also explicitly seeking someone right now (a co-founder) and leaving contact details gives an interested person a way to follow up with that.

</comment><comment><USER22> A related reminder: If you're active on GitHub, have contributed to any FOSS project, or have participated in any mailing list (including Google Groups), your email address is probably public already. So you can stop worrying about spambots harvesting your email address. All the spambots know about you already.

<comment><USER23> Correct. For some of us it is more about not linking our hn persona with our email. There exist a number of reasons for why this is beneficial to some of us: woking at certain places, families with certain ideas, living in certain countries etc.

<comment><USER24> Using an address from an email forwarding service such as spamgourmet might not mitigate all of these concerns, but it should mitigate some of them. Says the guy who doesn't have even a spamgourmet address in his profile. Hmm, maybe I'll do that.

</comment></comment></comment><comment><USER25> LEO and the NSA would like it if you add as much personal information as possible, so please do that and help them out.</comment>


We tested Secret's anti-bullying system and it failed - <AUTHOR> http://fortune.com/2014/08/07/we-tested-secrets-anti-bullying-system-and-it-failed/ <comment><USER2> Is this even a realistically solvable problem? When I was a kid, the bullies didn't need social networks to make us feel bad, and despite efforts by the school I went to, it's not like they could really stop them.

I'm glad Secret is attempting to not be a part of bullying, but expecting any net effect from the effort seems misguidedly hopeful that people who bully on its service won't bully somewhere else instead.</comment>


Slicing and dicing – making swords as game art props in vectors - <AUTHOR> http://www.2dgameartguru.com/2017/12/slicing-and-dicing-designing-basic-game.html <comment><AUTHOR> Here is another basics tutorial on creating your own game art props. It's time to start slicing and dicing with your own sort, using basic vector shapes in inkscape.

This tutorial is an addition to an early step-by-step tutorial on making an axe: [http://www.2dgameartguru.com/2013/06/hacking-and-slaying- bac...](http://www.2dgameartguru.com/2013/06/hacking-and-slaying-back-into- action.html)</comment>


The State of Caching in Go - <AUTHOR> https://blog.dgraph.io/post/caching-in-go/ <comment><USER2> Great article (or start of article)!

The GitHub stars obsession is too much, though. I read the request in the main content area, then a nag banner popped up at the bottom of the page requesting it again. How annoyingly desperate and uncool.

Enough already, I'm trying to read!

Or _was_ , anyway..

Plus I'm not even logged in to GitHub at present and cannot without getting to another device for 2FA.

No offense, but now I'll likely never give that star.

<comment><USER3> Arrr... Sorry about that. That was my idea, so my bad. We will get rid of the pop up banner.

<comment><USER4> Please do. Same here... read the initial request, but when the lower banner thing popped up _also_ begging for a star my perception of that was negative.

Clicking on the [x] in the corner of the pop up (to get rid of it) then launched a new window (well, new tab in this case).

Didn't read the rest of the post.

<comment><USER5> Do you mind sharing what browser/OS were you using? Clicking on the [x] shouldn't do that.

(i'm the person who implemented that widget)

<comment><USER6> On firefox on android, the X opens github

<comment><USER5> thanks, will look into that.

</comment></comment></comment></comment></comment></comment><comment><USER3> (co-author here) Thanks for sharing this post! We've elaborated the various issues we encountered trying to use a concurrent LRU cache in Dgraph and our dissatisfaction at existing choices which fail to provide memory management, high concurrency and hit ratios.

With guidance from Ben Manes, we're planning to work on a new concurrent Go cache based on Caffeine (Java). If you're interested in helping (or already have something similar), do reach out to us!

Meanwhile, check out Dgraph, our distributed graph database which is what keeps us busy: [https://github.com/dgraph- io/dgraph](https://github.com/dgraph-io/dgraph)

<comment><USER7> What are you thinking about for the API signatures? Without beating a dead horse this is where go's lack of generics really becomes burdensome.

If it were an on disk cache []byte would likely make sense but given it's in memory I'm not sure. If you use interface{} you'll need to measure that cost as well.

<comment><USER8> Our current plan is to store []byte given that badger stores blobs of bytes. Using interface{} may have some overhead, but we are no so worried about that right now.

<comment><USER7> So the []byte solution requires running through a serielization step which for most in memory uses will be expensive. Did you choose that because in you use case it eventually ends up setialized in any case?

<comment><USER8> correct!

</comment></comment></comment></comment></comment><comment><USER9> Cache hit ratio increases with the size of cache and decreases with the number of "hot" items regardless of cache eviction policy - LRU, FIFO, etc. Cache hit ratio reaches 100% when cache size becomes large enough to hold all the "hot" data. It would be great to see [https://github.com/VictoriaMetrics/fastcache](https://github.com/VictoriaMetrics/fastcache) in the benchmark results. It is faster and it uses less memory comparing to other solutions for caching the same amount of data.

</comment><comment><USER10> I think it is a well put together analysis, but I feel I'm missing something.

> FreeCache and GroupCache reads are not lock-free and don't scale after a > point (20 concurrent accesses). (lower value is better on y axis)

If you look at the graphs, they level out and seem to work best with more concurrent load, the exact opposite of what they say. Am I missing something?

Also, I think it would be valuable to see higher concurrent requests: with what I'm used to, 60 concurrent requests would be low - I'm interested in maybe 1-5k concurrent requests.

<comment><USER11> I agree, those graphs were pretty confusing. As far as I can tell, they are not showing the average time each operation takes (ie average elapsed wall time), they must be taking the length of the test and dividing by the number of operations. It would be much easier to parse if they showed operations/second instead.

In other words, 9 concurrent pregnant mothers would show 1 month/baby on those charts.

If I have that right, their comment makes more sense. After 20 concurrent requests, the overall throughput of operations/second does not increase with additional concurrency.

<comment><USER8> This is true that the latency of each operation won't change much as we increase concurrent accesses, but the amortized latency would (be expected to) reduce as the graphs show. When we did benchmarks, the Go benchmark framework provides us with ns/ops which we directly used to plot the graphs. We could calculate ops/sec too but that would just be another step of calculation using throughput = 1/(time taken/ops), may be more clear to understand though. The graphs would still flatten out after 20 concurrent accesses.

</comment></comment></comment><comment><USER12> The post speaks about go not having a thriving ecosystem of packages. My view is that there are actually a lot of Go packages out there but certainly go's indifference to packages and the fact it is just now getting an "official" package capability (RIP dep) has contributed to slower growth of the ecosystem. NPM has had many many growing pains but I sure do love the ease of use and discoverability of packages. I sincerely hope go catches up. I love the language and tooling.

<comment><USER13> Go has lots of packages. They are easily discoverable on godoc.org or just some googling.

There is a cultural skepticism about the overuse of packages. There are occasions where the STD lib copied a function instead of adding an import for example. Like many things in Go this pushback is needed but sometimes goes too far.

But maybe single function packages in npm we're a bad idea.

Anyway caching is a mixed bag in my opinion. Local per-thread caching is often better than a global cache as it avoids contention. It's also trivial to implement with a map and requires no special coordination.

It does require rethinking how you design a solution to a problem. FWIW that design process tends to lead you down a better direction anyway for producing distributed systems.

For example one giant, randomly distributed Kafka topic with a global redis db for a cache is probably a lot worse off than a system with more predictable data locality on the consumers.

<comment><USER3> (co-author here) The number of Go libraries tend to be just slightly below the number of their users (dramatically speaking).

Libraries are hardened by repeated usage by many different users who each bring their own special use cases and improve them to bring them to production quality. Go has no platform where certain well-written libraries can be recommended and get more exposure. Thus, they don't tend to mature more than the specific use case they get written for, provided they are still being maintained.

Arch Linux is a great example of giving well-doing packages more exposure by upgrading an AUR to community to core/extra. That way, more users gather around packages improving them even further.

To the second point about per-thread caching, Go does not expose threads to end-users. So, there's no concept of thread-local. What you're describing results in lock striping, which has contention issues as described in the post.

<comment><USER14> > Go has no platform where certain well-written libraries can be recommended > and get more exposure.

Godoc.org is that platform, it serves the purpose. Others in the module universe are under development.

> To the second point about per-thread caching, Go does not expose threads to > end-users. So, there's no concept of thread-local. What you're describing > results in lock striping, which has contention issues as described in the > post.

In Go you'd have to orchestrate this locality yourself, i.e. a fixed worker (goroutine) pool each with its own cache. This is probably less work than it sounds.

Generally, Go does encourage you to author solutions to your specific problem, rather than adapting a general-purpose library. This is almost as much a part of the ethos of Go as implicitly-satisfied interfaces, or "share memory by communicating", or any of the other proverbs. Maybe Go takes it too far. But effectively no other language exists at this point on the spectrum, and I'm happy that we have at least some representation over here; I think lots of programmers live here, too, and appreciate the tradeoffs.

<comment><USER3> > Godoc.org is that platform, it serves the purpose.

Godoc.org is great. But (beyond documentation) it is at best a search engine, providing equal platform to all libraries however production ready or broken they might be. Unless I'm missing something, it does not intend to promote certain libraries over others, the same way as AUR -> community -> core works in Arch (which is the model I think is missing in Go).

> In Go you'd have to orchestrate this locality yourself, i.e. a fixed worker > (goroutine) pool each with its own cache.

Having many small caches within the same process would result in more misses per key, which if it results in disk accesses would not be ideal or might be worse than contention.

Moreover, being able to spin Goroutines as and when required to branch off a big job into smaller tasks is the beauty and benefit of Go compared to other languages like C++ or Java, where you must start a thread pool upfront and shoot tasks off to it.

<comment><USER15> >the same way as AUR -> community -> core works in Arch (which is the model I think is missing in Go).

Arch packager here.

It doesn't _quite_ work like that. The distinction between community and extra is largely based on who packages it, it used to be defined as above 5% usage. The distinction between that and core is that core is considered essential to the distribution. No package is going to go from AUR to core without replacing some integral part of the system.

<comment><USER3> I see. Then I guess there's a different model that can more accurately represent the idea of giving certain well-written/actively-maintained/popular packages a special platform than others to make it more enticing for wider community to adopt those.

The underlying issue is that building a production ready library doesn't just happen -- it needs one or few initial authors and (along with a large group of users) a group of dedicated power users who can then continue to maintain the library and optimize it for their usage, in turn developing it enough to be considered production ready.

</comment></comment></comment></comment></comment></comment></comment><comment><USER16> I'm not very familiar with go but one thing I don't understand is why the caches need to be distributed. I wonder, why not just have one cache per thread?

<comment><USER17> That requires N times more memory, where N is the number of threads. 32x more memory??

<comment><USER18> Given the Zipf distribution, I wonder if just a small LRU cache per thread might not be a terrible thing?

Juggling caches on databases is a challenging thing, and there has been some back-and-forth on best practices. MySQL for the longest time shipped with a query cache. As of MySQL 5.7.20 it was deprecated, and has now been removed in MySQL 8, largely because it was as likely to hurt you badly as help you, particularly with correctly sized InnoDB buffering.

<comment><USER19> Zipf is a little idealistic. It is perfect for a quick analysis as the base case that a cache should excel at. Unfortunately LRU doesn't because it can be easily polluted. (examples: [https://github.com/ben- manes/caffeine/wiki/Efficiency](https://github.com/ben- manes/caffeine/wiki/Efficiency))

A database will often scan many records which would flush an LRU. Postgres uses small LRU buffer caches in your per-thread model, backed by a larger LRU- like cache. The buffer caches are easily flushed by scans, but protect the shared cache from this noise. That shared cache could probably benefit from a smarter policy and this is an on going topic.

</comment></comment></comment></comment><comment><USER2> > LSB 9-16

What is this? Google thinks it's some sort of metal stamp.

<comment><USER20> Least significant bits

<comment><USER2> Makes sense now, thanks!</comment></comment></comment>


Ask HN: What tools and workflows for project tracking? - <AUTHOR> I'm curious what tools and workflows people use to keep tabs on a project.<p>My situation is a small team with remote devs and multiple communication channels (Slack, Skype, etc.). Code and tickets go through GitLab. <comment><USER2> As a company, we use Atlassian Stack + Skype like most others do. So, Jira (issue tracker), Confluence (documentation), Stash/Bitbucket (git + review), Bamboo (ci), etc.

Personally, I also have Jira, Confluence and Bitbucket licenses but I mostly use GitHub's issue and wiki pages and Travis.

Since you're using GitLab already, I think it's best to stay in there. It has a nice issue tracker and issue board as well as other things you might need.

</comment><comment><USER3> Trello is a common one. Tbh email is still probably the dominant project- management method, despite being clunky and inferior, especially at smaller places with smaller projects.</comment>