Solution to Harvard's admissions problem is simple: run a lottery - <AUTHOR> https://qz.com/1520155/harvard-needs-to-introduce-a-lottery-for-truly-fair-admissions/ <comment><USER2> So here's the thing: a student body is more than the sum of its parts, which a lottery ignores.

To use just one example: a lottery could easily wind up admitting 40 violin players and zero bassoon players, or 8 percussionists but not a single oboe player. In which case a viable university orchestra becomes impossible, and every potential orchestra player suffers. (These are not exaggerated either -- for an incoming class of 1,000 students, of which only ~100 have a sufficient orchestra background with the requisite years of practice and want to play, there isn't a lot of margin for error.)

Now repeat ad nauseum for every type of sports team, extracurricular, distribution across majors, etc.

By ensuring there are approximately the right number of every "slots" for each type of applicant, the institution ensures that students have the ability to participate in the types of activities and courses they want to, and that student life is rich both academically and extracurricularly.

There are legitimate problems with some of the "slotting" as practiced today (particularly concerning legacies and in terms of whether a racial/ethnic/national balance should match the nation, the applicant pool, some other balance, or be ignored entirely), but a lottery would throw out the baby with the bathwater, and be a disaster for ensuring the kind of vibrant student life that is a major part of 4-year university experience.

(Obviously this is specific to smaller institutions, whether elite or not -- if your incoming class is 30,000 students then you'll always have enough of everyone.)

<comment><USER3> Harvard using a true lottery would be a self-inflicted wound. A lot of Harvard's value is because it's Harvard. Harvard lowering their perception/brand/prestige is a lose-lose for themselves and the students/alumni (note: actual students, not prospective students).

Think about it this way: the nature of the game is like investing - it's about Harvard picking winners. Harvard is like the well-known VC that can say they funded <this many> unicorns, and being a part of Harvard means being associated with success. Harvard may take some waivers on higher-risk/less- fortunate students for diversifying investments, but it's only one piece of the portfolio. Selectivity is a key ingredient to their ROI, endowment fund, and social capital. Harvard is a private university and cares about their private equity and capital in a way that is different from public universities.

<comment><USER4> This is the problem I have with higher education. It is not about the effectiveness of the education, but the signal of effectiveness. "Social Capital" is a zero sum game. If someone gains social capital, another must lose. Actual education, on the other hand, is not.

It's really a shame.

</comment></comment></comment><comment><USER5> This presupposes that colleges truly want their admission process to be fair, which they absolutely don't. Then, how would they get to admit legacy students with wealthy parents?

Also, admitting that getting admitted is based on luck directly contradicts the narrative of meritocracy in college admissions, which would decrease the perceived prestige of the school. So yeah, no way would Harvard go for this.

<comment><USER6> I think that a lottery _without_ a qualification threshold would contradict meritocracy. In contrast, I don't think a threshold-based lottery contradicts meritocracy. Rather it can be interpreted as a claim that meritocracy cannot be properly quantified beyond a certain precision (which in this case is the threshold). Even if you disagree with that premise, it's substantially different than the rejection of meritocracy altogether.

I also don't think it presupposes anything about what colleges want. What colleges _want_ isn't relevant to a claim about what _would_ be more fair. The paper this article is based on doesn't make an argument for how to force or persuade colleges to espouse the system. It only argues that this system is closer to a platonic ideal of admission fairness.

<comment><USER5> I think the point is too subtle to be broadly appreciated. Any crack in the dam of meritocracy is likely to become a flood. The illusion must be preserved.

wrt to point 2: I guess it's about perspective. It's fine to propose systems that in theory would be nice but without an eye towards what could actually work, what's the point?

<comment><USER7> A good example of the crack/flood analogy is the current H1B visa system. You do have to be qualified to apply, but if enough people qualify a year, they distribute the spots randomly. Eventually the general public started referring to it as "H1B lottery" and assume it's all a matter of luck.

<comment><USER8> I mean because at that point it is a matter of luck. You can pretend it's not but when everyone is qualified there stops being a real difference between candidates. I think a lottery for higher education works the same. At joe blow public school that may not be true but at an institution like Harvard, they receive so many qualified applicants they could probably choose and entire class full of any one special interest group and still leave out qualified candidates. The difference between student A and B don't really matter when they are both exceptional

</comment></comment></comment></comment></comment><comment><USER9> _" The admissions lottery I envision—which would involve applicants who meet a certain academic threshold—would help universities faced with large numbers of qualified applicants, such as Harvard, admit students in a more equitable way."_

The whole point to the modern university application process is they want more axis than academic achievement with which to evaluate prospective students. Did you play and do well in sports? Are you accomplished in any of the arts? Are you a chess master? Did you build a great robot winning several competitions? This is _true_ student diversity, it's not just race and class - and it provides a differentiator between those who just studied and got a perfect SAT score and those with other accomplishments who also happen to have a near-perfect SAT score. The lottery system depicted here is unfair to those students who've gone beyond and accomplished things. We need to recognize accomplishments outside of the classroom are important.

<comment><USER10> > The lottery system depicted here is unfair to those students who've gone > beyond and accomplished things.

Conversely it might take some of the pressure off.

As it stands there's never "enough." With a system that effectively caps you, you get to your lottery tier and can then back off. And considering how much the standards have increased over time to get into a school like this, that may not be a bad thing for mental health.

<comment><USER11> Would you really want a future Feynman to be playing an admission lottery?

<comment><USER12> ...kinda, yeah. Feynman's an interesting choice of example, actually; he wanted to attend Columbia, couldn't get in because of anti-Semitism, and then attended MIT before it was "MIT, Famous Engineering School", when it was still basically seen as a vocational school for middle-class students. I think the whole higher education system would benefit from having people like that scattered throughout it, rather than concentrated at a handful of elite universities.

<comment><USER13> The problem isn't that we miss out on some specific genius. The real issue with our system is that we have "Feynmans" working as waiters and driving taxis (and some other countries don't have that system and are maximising their talent).

It is interesting to critique this idea for introducing chance. Pitch this idea to a poor person, pitch this idea to a rich person...that is your answer. It is hard to understand if you grew up with opportunity but for poor people this randomness represents a tremendous improvement. From a system that is designed to crush them, to one in which everyone has the same chance.

<comment><USER12> Absolutely agree. I don't know how much this particular proposal would help them, though; I think catching those people would require a wholesale overhaul of the educational system: universal free pre-school, standardizing school funding nationwide (and specifically decoupling it from property tax revenue), fully subsidized university education for anyone who wants it...and then lotteries to get into elite schools.

Otherwise, I suspect this would primarily benefit middle class students who can afford to pay for test prep and tutors, but not for a month-long volunteering stint in Nepal, and primarily hurt the relatively-sub-par-but- well-off legacy admits (which, who cares) and students with a lower SES that currently get a boost from consideration for that status/the follow-up effects of growing up and going to school in poor areas (which I do care deeply about).

<comment><USER13> Yep, I agree. The reason we have this problem at all is because, at least in our part of the world, education isn't well-funded. I think we should still have a lottery system but yes, other stuff will produce better results.

I also think that all the volunteering and whatever should be cut from applications. Who gives a fuck if you played the oboe for ten years? Does that really matter? The point of music is enjoyment, the point of volunteering is to serve other people. I had a friend who was forced to play the saxaphone until university and it was tragic: he wouldn't talk about it, he only played to pass exams, he took no joy from it...like great but if you are being forced to do this then who cares? It has become another way to discriminate...and it isn't that much fun if you are a kid.

</comment></comment></comment></comment></comment></comment></comment><comment><USER6> The article is substantially predicated on a recently published paper[1] which proposes a threshold lottery for university admissions. Among other things, this paper directly kicks off discussion of several basic criticisms that could be levied against lottery-based admission, such as (for example) the definition of fairness.

In particular, note that the definition used in this context is an admission lottery such that, for all applicants at or above an explicit baseline of qualification, each applicant is _equi-probable_ of being admitted. It's also worth noting the author explictly states the system is pragmatic for distinguishing between qualified candidates of increasingly insignificant meritocratic differences; however, it may not be compatible with "general welfare."

1\. [https://www.jstor.org/stable/10.1086/670663?seq=1#page_scan_...](https://www.jstor.org/stable/10.1086/670663?seq=1#page_scan_tab_contents)

</comment><comment><USER14> For those who aren't following closely:

Harvard, like many Universities with applications from far more candidates than they can accept, filter applications based on perceived desirability. For example, a student with the same academic background is more likely to get admitted if they come from Wyoming or Maine than New York or California; in the name of having a more diverse student body with more diverse interests and upbringings, rather than just upper-middle-class students from coastal cities.

There is, of course, a racial component to this.

Today, qualified Asian-American applicants are overrepresented as a share of the overall population, due to great academic qualifications.

Harvard has been found to be accepting them at a lower rate than you would expect; if you look into it, there's some "desirability" factor that's bringing them down. Obviously this is very controversial.

"Students for Fair Admissions" was created by Edward Blum, a Neo-Conservative activist and AEI fellow who is well-known for his work against the Voting Rights Act of 1965, for attempting to reduce the population-based power of districts by only counting registered voters as persons, and generally recruiting 'victims' of affirmative action to be subjects of test-case lawsuits in order to advance his political beliefs.

<comment><USER15> I think there was some studies that showed the share of spots that would have went to Asian Americans effectively transferred to white women. In that sense, not sure if Asian Americans were the only "over-represented" demographic segment.

</comment></comment><comment><USER16> The problem of college admissions seems similar to the problem of selling tickets to a hot event. The free market solution to selling tickets to, say, a Red Sox game is to charge as much as you possible can until people stop buying tickets. But you get a problem. You make the less wealthy fans very unhappy because they have no choice in being able to attend. This has long term consequences. So the Red Sox, for instance, sell tickets for less than what the market would allow. Then you get the mad rush for the first come, first serve ticket sales.

<comment><USER17> So basically supply and demand?

<comment><USER16> The problem is that the usual way of solving the supply and demand problem in the free market has consequences that many people dislike.It doesn't seem fair for only rich people to attend baseball games. It doesn't seem fair for only a select few of those qualified get to go to Harvard.

</comment></comment></comment><comment><USER18> This would destroy their business model which is predicated on getting into Harvard being an "expensive signal" of intelligence, industriousness, and future potential, which is why they will never do it. But I agree with the points in the article!

</comment><comment><USER8> I agree with the premise of the article in that a lottery for those pass a given threshold is the only truly fair wait to admit students to Harvard. The problem I see though is that really doesn't help the image problem of any of these institutions. Simply put if one of your goals is to ensure a diverse student body, unless you start adding quotas and doing a lottery for specific categories (which is largely problematic in and of itself) you are going to end up with a pretty uniform student body. Certain groups of people will be over represented in the pool you are selecting from and thus while any singular student has an equally likely chance to get in, the overall diversity numbers probably aren't going to be so great. Maybe that's fine if it's the most fair way of selecting students but there's definitely an argument that all you are doing is reinforcing the institutional disadvantages of the non wealthy and minorities.

</comment><comment><USER19> The author's article is on a question that I considered before. I agree with her that it may make the process more 'fair', however, she fails to consider one consequence of a switch to a lotto based system. Namely:

How Much _Should_ a Harvard Lotto Ticket Cost?[0]

The author mentions that "This system would also alleviate the cost to families associated with students applying to increasing numbers of colleges", but I disagree. If you look at the system in terms of expected value, then what _should_ you pay for that lotto ticket? (Note, I'm quoting a bit from my article, please excuse the laziness)

Assume that you are actually applying to Harvard and they actually confess to using randomness in their admissions. Say that they still require a fee to submit your application. Today that fee is sitting at $75.00. Say that the 'prestige' of Harvard remains the same after this hypothetical confession to the use of randomness and that today's median salary for a Harvard grad stays at ~$85,000.00/year.

The questions then is: Should you apply to Harvard and hope to be a random applicant that gets in at the $75.00 price? Should you place a bet?

After you go through the math and stats for a bit, the conclusion is that the price of a Harvard Lotto ticket _should_ be ~$89,823.00 . That's ~1200:1 on your money. You should _absolutely_ apply to Harvard if they held a lotto, and even if the number of applicants rose ~120,000%.

I go through each of the Ivies and there is an update at the bottom on the top Universities and Liberal Arts schools in the US. Spoiler: CMU is not very 'worth it' (still a steal, all the same) and Carleton and Davidson are very 'worth it' for the admissions price.

In the end: Go to college kids. The ROI is insane.

[0] [http://heffern.net/rob/index.php/2018/05/18/hello- world/](http://heffern.net/rob/index.php/2018/05/18/hello-world/)

</comment><comment><USER20> From a statistical perspective, in a fair random lottery, would not the shape of the probability distribution of attributes of winners necessarily match that of the resulting qualified applicants?

If fairness is defined in this approach as a process that does not add information to the system, and in this case actually removes both information (bias) and noise (bias) equally, all it would serve to do is further obfuscate the cause of being admitted.

For an admissions lottery to be considered "fair," you have to assume the participant selection is fair, and that the functioning of the university itself is indifferent to who it gets. Maybe they should A/B test it, where some are admitted at random and their success compared against the traditional admissions process. Arguably, that's even what "legacy," students provide, a sample independent of the admissions process.

That we're having this discussion at all is a greater indicator of the waning of the university system as meaningful process, and how undergraduate education is subject to Goodhart's Law, where it has ceased to be a useful measure of aptitude, competence, or much at all anymore really.

<comment><USER6> I don't really follow your first two paragraphs. I don't know about the ultimate utility of this system, but I don't think it exhibits the statistical properties you're saying it does.

In a threshold-based admission lottery, everyone more than _k_ sigma from the mean (for example) is collapsed into the same category, such that information distinguishing them is lost. But the implicit premise to this system is that you can't accurately measure the distinctions between those deviations anyway.

Given that premise, you're not adding noise to the system, though you are removing information. I think the claim under question is that trying to precisely measure people more than _k_ sigma from the mean is intrinsically noisy and prone to spurious correlation with academic success. So then you'd also be removing noise under this system.

So I think your point of contention should be with the premise if you disagree with it, because I don't think we can really argue about statistical properties of the lottery distribution until we first settle on the underlying axioms.

<comment><USER20> The point I meant to raise was that the underlying axiom of the piece is that the lottery is fair, when the mechanism for that fairness is simply removing information. There are lots of reasons for it, but a lottery is a fig leaf.

The proportion of input students of a type will be the same as in the the output of a fair lottery. Appeals to randomness just forfeit responsibility and ownership of the decision.

</comment></comment></comment><comment><USER11> Who says that the threshold, as measured by e.g. SAT scores, is a good threshold for a good measure?

<comment><USER15> There is a way to settle the fairness of process: re-run admissions process where all data points that indicate demographics are scrubbed (name, ethnic organization memberships, etc). See if the admission rates change.

</comment></comment><comment><USER21> I've said this before and I've said it again - I'm genuinely not sure about why we invest so much mental anguish about discussing $ELITE_SCHOOL's admissions process _at all_. If we're talking about opportunity, shouldn't we instead aim to provide opportunity for the 99.9% of people that either can't (me), or didn't go to the same handful of elite universities?

<comment><USER12> Well, the cynical answer is that the elite schools churn out the people who go into the media, government, and various other halls of power, so a lot of the chatter is actual graduates of these schools discussing their own alma maters, and they've essentially worn down the rest of us into caring. But a slightly less cynical take is that this stuff all trickles down through the rest of the higher education system, because of the aforementioned dispersal of elite university grads into positions of power, so fixing the culture at those elite schools would probably result in positive changes in the institutions they influence.

</comment></comment><comment><USER22> Harvard doesn't have an admissions problem, they have an image problem that was brought to light by a controversial lawsuit. The institution known as Harvard is basically a massive investment firm that just so happens to run a school -- if Harvard's (and other elite, mega wealthy colleges) stated mission was to promote general education they could open up additional campuses and increase admissions without sacrificing much in the way of educational quality. Even if Harvard was half the school it is today it would still be a fantastic education.

Harvard is trying to have it's cake and eat it too with it's selection process, there are a set amount of priorities they have with each class and need to balance these priorities out, namely: Admit enough legacy / wealthy students to placate the donor class, have a relatively diverse set of kids so that they can claim diversity, grab some kids with "exceptional talent" (maybe a great musician here and there) and pad out the rest with kids that have perfect SAT scores.

I honestly don't think this is a problem that can be solved. Harvard deliberately caps the amount of students they accept and their capacity to accept these students to maintain it's elite reputation, combine that with the fact that their student body needs to reflect the principles they tell the world (diversity more so that absolute quality) and you will have situations like this.

</comment><comment><USER23> This is not a new idea. It has been generally suspected for years that Harvard selects students by throwing their applications down a flight of stairs and seeing who lands on the right step. As far as I can tell, it's working just fine for them.

</comment><comment><USER24> I've heard that with the size of Harvard's endowment, it would be trivial to cover the costs of tuition for all students. Pitching random admissions as a cost cutting measure seems unconvincing against this backdrop.

</comment><comment><USER25> Would it be a problem to remove all identity categories (name/legacy/gender/ethnicity/origin/etc) of applicants and simply admit the most qualified students?

<comment><USER12> "simply admit the most qualified students" is the "assume a spherical cow" of the college admissions discussion.

<comment><USER25> Why?

Is this not supposed to be an elite university for elite students?

<comment><USER12> Well, that's certainly what Harvard would argue, although a lot of people might disagree, but even if we accept their/your framing, that doesn't solve the issue. You're throwing around "most qualified" and "elite students" like those are settled terms of art, rather than the heart of contention in an argument that's more than a century old.

Imagine two hypothetical students. One student graduated with a 4.3 by taking advanced courses at a high school where every student gets between a 3.5 and a 4.5 thanks to some combination of intelligence, good funding, grade inflation, and a parent population who can pay for a new wing or two if it means junior will graduate on time. The other student graduated with a 3.8 from an underfunded high school on Chicago's South side, where the average class size was 30+, the textbooks are 20 years old, and the average annual family income is around $30k. Which one of those students is more elite? Which one is more qualified?

Zion Williamson is currently a student and a basketball player at Duke University. He's 6'8", weighs somewhere in the neighborhood of 280 lbs., and a few days ago he had a highlight where he started from under the hoop, sprinted out towards the three point line some 22 feet away, leapt towards a player on that line who was taking a shot, blocked the shot in mid-air, and landed without touching the shooter. The number of people in the United States with that combination of size, speed, and skill is in the single digits. The number of people in the world might - might - be in the triple digits. Is he an elite student? If so, is he more or less elite than the other students in the previous paragraph?

There isn't a clean metric for most qualified or most elite, and there really can't be, because the world doesn't neatly standardize like that. It's a symptom of insufficient consideration of the problem to suggest that fixing a massive and massively flawed system is super simple and just requires One Neat Trick that the thousands of people who have been thinking about and working on this for decades haven't considered.

<comment><USER25> > There isn't a clean metric for most qualified or most elite, and there > really can't be

For an academic institution or an athletic endeavor, I completely disagree. Performance in these environments is measurable. Elite performance is obvious, observable, and measurable.

Should a theoretical elite university basketball team sign and start a 4'11 80lbs person who makes 1% of shots and has only played basketball maybe a half dozen times before total but they happen to be the very best player from their school? What if they're technically the best basketball player in their schools history? Are they therefore an elite basketball player, and an elite performer? I would say no, observably and measurably not.

</comment></comment></comment></comment></comment><comment><USER26> Harvard doesn't have an admissions problem. It's a highly successful institution, that has lasted for hundreds of years and is not public.

Meaning - they clearly are doing something correct and are not beholden to what we feel is "fair". They aren't doing anything illegal, so there is no problem.

Perhaps it doesn't jive with some sensibilities, but it's not their responsibility to cater to anyone's sensibilities. The institutions purpose is to grow and support its pupils. Then it's pupils pay dividends back to the institution. Anything counter to that, really doesn't make sense.

<comment><USER27> > They aren't doing anything illegal

Isn't there an active lawsuit claiming their use of race in the admissions process crosses the line?

<comment><USER14> Yes, a conservative activist has recruited test-case students as plaintiffs in lawsuits designed to strike down affirmative action.

<comment><USER28> If the merits of the case are justified, what does it matter whether an "activist" is involved or what his politics might be?

</comment></comment></comment></comment><comment><USER29> Or they could just admit more students..

</comment><comment><USER30> "Special status may also be given to increase opportunity for underrepresented groups, in the interest of campus diversity." That's all fine and dandy as long as people still enter by own merit and not to artificially inflate diversity, which seems like an ongoing trend in American academia.

<comment><USER31> "Increasing opportunities" and "artificially inflating diversity" are effectively two different definitions of the same thing. It may be a good or a bad thing, but we can't have one without the other.

</comment></comment><comment><USER32> Fairer? Yes. Better? No.

The college application process screens for more than just measured ability, and forcing colleges to take on people who aren't a good culture fit changes the experience at that college for the worse.

<comment><USER33> It may change the culture at some schools. Whether that would be better or worse remains an open question.

</comment></comment><comment><USER34> When I was in high school there were exactly 4 people in the country with perfect SAT scores. Now, according to the article, there are thousands. Maybe they could start there.

And just to stave off the criticisms - yes, they made the test much easier.

<comment><USER35> The article mentions perfect _math_ SAT scores. A perfect SAT score is much more rare.

</comment></comment><comment><USER36> The true solution though, would be for people to wake up and realize that in most cases, those so-called "ivy-league" colleges set you up for nothing you couldn't have gotten elsewhere. That you're NOT in-fact better off at 22 with a 150,000$ debt, which you could've avoided by attending a different institute. That the quality of education in "less prestigeous" universities doesn't necessarily "fall" from that of Harvard's.

Edit: Addressing the comments about how it's all about joining that Alumni circle.

I've attended an ivy-league alumni dinner party recently (graduates from multiple "high profile", internationally acknowledged institutes). Save for several senior people with interesting stories, most others were working on their "next Lyft"/"next Airbnb"/"Facebook for %s"/"%s but with AI!" startups. Everybody had a suit and a nice lapel pin to show for it though. Some even wore a bow-tie, no less!

At some point it stops being a club of outstanding members of society, and instead, it becomes a "I took a huge loan to buy my way into this" club. Make of it what you will.

<comment><USER37> The education isn't anything special. For certain circles, though, the _status_ of an ivy sheepskin is of utmost importance. State U isn't good enough for the silver spoons. Harvard is also not indebting those lucky enough to attend given it's generous scholarships.

<comment><USER25> The value in elite universities is the network</comment></comment></comment>


Cuckoo: a memory-bound graph-theoretic proof-of-work system - <AUTHOR> https://github.com/tromp/cuckoo <comment><USER2> How is the power consumption compared with other PoW e.g. SHA1?

<comment><USER3> With Cuckoo Cycle, you pair every siphash evaluation (mapping 64 bits to 64 bits; a much cheaper hash function than SHA1 by an order of magnitude) with a random memory access. As a result, most of the power consumption will be from the memory subsystem. I believe a DRAM chip draws on the order of 1W.

So you should be able to run this on a smartphone, while it's charging overnight.

</comment></comment><comment><USER4> According to the paper "Asymmetric Proof of Work based on the Generalized Birthday Problem" (appearing at NDSS 2016, a top security conference) [http://orbilu.uni.lu/bitstream/10993/22277/1/alex-dmitry- asy...](http://orbilu.uni.lu/bitstream/10993/22277/1/alex-dmitry-asymmetric- PoW.pdf) the Cuckoo puzzle is amenable to parallelism, and thus potentially a "time-area" tradeoff. What do you think?

<comment><USER3> The project page states that "trading off memory for running time, as implemented in tomato_miner.h, incurs at least one order of magnitude extra slowdown"

For instance, to look for a 42 cycle on a billion node graph, the reference algorithm uses 128MB.

If you want to get by with only 32MB, then you can run that alternative algorithm, but it will take about 128/32*25=100 times longer. The penalty factor of about 25 is due to losing the ability to represent edges with a single bit.

You can also parallelize by having more cores share the same memory but this it only takes so many cores to saturate a memory bank.

That paper sadly misrepresent Cuckoo Cycle by focusing on an outdated version from the first half of 2014 (and incorrectly describes it as working on directed graphs).

</comment></comment><comment><USER5> The big problem with an algorithm like this on is that there is a fair chance that someone will come up with a substantially faster method. This part bothers me:

>These bounties are to expire at the end of 2016. They are admittedly modest in size, but then claiming them might only require one or two insightful tweaks to my existing implementations.

</comment><comment><USER6> Does this solve the centralization problem of Bitcoin (Chinese miners etc.)?

<comment><USER3> Cuckoo Cycle author here. In the recent thread "The resolution of the Bitcoin experiment" I commented:

Bitcoin mining could be more decentralized if it better resembled a lottery, where huge numbers of people play for an expected loss. In other words, the lack of people mining at a loss makes mining profitable and hence subject to forces of centralization.

There are several reasons why mining as a lottery substitute is rare, a major one being that commodity hardware is inefficient by many orders of magnitude, making even a botnet next to useless. Perhaps, if a proof of work, whose efficiency gap (with custom hardware) is at most an order of magnitude, were adopted (or slowly phased in), enough lottery players would arise to make mining unprofitable at scale.

Botnets should then just be welcomed as a modest increase in decentralization.

</comment></comment><comment><USER7> Interesting. I wonder how a sat solver would do with this problem.

<comment><USER3> How would you express a 42 cycle in SAT? How much memory would that take for a billion node graph?

The Cuckoo Cycle algorithm only needs 128MB and a few seconds to solve this.

<comment><USER7> > How would you express a 42 cycle in SAT?

That's easy. You just need to design a combinational circuit that verifies that a particular list of nodes forms a cycle.

> How much memory would that take for a billion node graph?

Naively, a lot. Thinking about it, way too much memory to be in any way practical.

However, there may be a good way to solve it with an incremental solver or, instead of materialising the graph, you could encode the siphash function in the sat solver. Then it would use much less memory.

If that works well though, it would compromise the original goal of the project.

<comment><USER3> I don't see how that could possibly work well with all the overhead. Remember that the reference algorithm can be viewed as an exceedingly optimized SAT solver, using exactly one boolean variable to say whether a particular edge is used in the cycle or not.

</comment></comment></comment></comment><comment><USER8> Umm.. wouldn't it be better (for the environment) if you just donate the CPU time to folding@home or similar thing and they would certify that you donated?

I think someone suggested there already is a cryptocurrency like that.

<comment><USER9> There are a couple of cryptocurrencies based on this idea (CureCoin [1] and FoldingCoin [2]). But as far as I can tell these both rely on a trusted third party to distribute the folding work and verify that it was done. That's because unlike hashcash and similar proofs of work via hashing, protein folding is not cheap to verify.

If you're concerned about energy use and willing to trust a third party to verify the transactions, then why not use VISA?

(I looked at the CureCoin site and skimmed the FoldingCoin white paper [3], but I couldn't find any description of how they verify the folding work. Can someone point me at an explanation?)

[1] [https://www.curecoin.net](https://www.curecoin.net) [2] [http://foldingcoin.net](http://foldingcoin.net) [3] [http://foldingcoin.net/the-coin/white-paper/](http://foldingcoin.net/the- coin/white-paper/)

<comment><USER8> > If you're concerned about energy use and willing to trust a third party to > verify the transactions, then why not use VISA?

Well, that's my question.. They are already willing to trust the party that generated the code that they had legal access to their computer for this purpose. I think we would all be better off if they just required proof of monetary donation to some charity or something.

All that was accomplished here was shifting of trust on these individuals at some energy expense; it's insane.

It's nice theoretical exercise for sure, but I sincerely hope that anyone attempting to build yet another monetary system on waste of energy will seriously reconsider the idea.</comment></comment></comment>


Possible monetization strategies for Secret - <AUTHOR> http://blog.namomedia.com/post/79984491919/secrets-secret-monetization-strategy

<comment><USER2> They missed out on 'how much would you pay to know who just posted this post?' followed by 'would you pay more than $x to keep your anonymity?' :-) (I'm joking of course)

I suppose if they wanted to, they could pivot to 'secret' deals, which is they get advertised to folks using the app only. But I really don't know how compelling that hook would be.

<comment><USER3> So you're kidding about the "ransoming" bit.. but why not have an auction or pledge for 'how much would you pay to know who just posted this post?' and then allow the author to click accept/reveal or no/keep hidden. Could also have an option upfront for disabling the feature (maybe only disabling on the author's end, to ever reveal, but let user's think they can bid it up).

Got me intrigued at least.

</comment></comment><comment><USER4> "Advertising" isn't that big of a secret. It seems like the default monetization strategy. If that is the strategy, it's all just in the tactics and targeting.

Ads aren't the most innovative way to make money, but it's not easy, either. Reddit, for example, still hasn't remotely figured it out despite huge potential and an enormous user base. FB and Twitter are getting there, but it's not been an easy road and investors are still expecting more.

<comment><USER5> Everyone on Reddit uses adblock. Besides, any major change to the Reddit advertising model would have a chance of making everyone leave, like when everyone on Digg left for Reddit.

Reddit Gold and similar features are working much better at monetization than ads ever did. They're getting closer to breaking even these days, according to their blog.</comment></comment>


Homeless man lives off reward points from former life - <AUTHOR> http://www.ocregister.com/articles/kennedy-238295-points-job.html

<comment><USER2> These stories are always so difficult to read and for me sometimes hard to imagine. It seems like everywhere I love people are having a hard time hiring people and the thought of laying off someone is absurd. It's so bad that I've seen companies keep people they are know are incompetent because they figure it's better than nothing. It seems like there is a huge disconnect between the experience of parts of the economy and the country in this recession.

It's hard for me to imagine not being able to earn an income or provide for my family but that's the reality for a lot of people right now. It's good to remember that and be thankful for where you're at and what you have.

</comment><comment><USER3> Perhaps he should have saved something besides rewards points when he was making 6 figures?

It would however make an intriguing plot point in some dystopian movie where everyone's retirement savings plans have been replaced by reward points from various big companies. Be a good consumer all your life and retire happy!

<comment><USER4> He lost his job almost 2 years ago and lost his house just recently; he could have spent his savings trying to keep an expensive place while trying to find a job. If so, I agree that doing so was unwise, but homes are things that people can be unreasonable about.

<comment><USER5> He lives in Orange County, and was a former sales exec for Oracle. The only thing he saved was the extra cost on his mortgage when he took out a negative amortization loan on the million dollar mortgage for his home.

<comment><USER4> Ah, OK.

</comment></comment></comment></comment><comment><USER6> The vitriol around this guy on the O.C. Register's comments section is just too much. Dude's been out of work 19 months and his house just foreclosed on him, and some of the comments are like, "yeah, this jerk is fat and old and he has a giant wine collection and a lease on his car."

If anything, he seems pretty resourceful. That Oracle bit seems like a smart little bit of logic for someone in this guy's situation. And why should he have to give up every detail of his life because of his bankruptcy and foreclosure? He could have a job next week for all we know.

The people getting screwed by this economy are in this guy's demographic. I've seen way too many newspaper types (many friends) lose their jobs during the so-called "salad days," because it's cheaper to keep around the young guns.

Though I will say this much: How much did this guy save while working if he had to file for bankruptcy? And how quickly do you plow through all that savings?

<comment><USER7> I think the lack of tact and kindness is wrong, but the sentiment may be fairly on par. Things are different in other parts of the country. A lot of people can't dream of affording a lease on a car like that job or not. I'd love to be _able_ to afford 25 dollars a day for rent but the reality is a lot of us who are actually working are being far, far more frugal than this guy is when he is out of a job. The realities of life just aren't the same in the rest of the country.

</comment></comment><comment><USER8> It says something interesting that he can so easily go from making 'six figures' to nothing.

If we exclude the 'blame the economy' explanation, then it seems to me that either:

a) he was never worth 6 figures in the first place; or

b) he has contacted only companies that could have no use for him; or

c) he has contacted companies not covered by b) and they have all made six- figure-scale mistakes by not offering him a job.

My cynicism inclines me to a).

<comment><USER9> There's another option. He was worth 6 figures if he was making sales of, say, twice his salary. If fewer companies are buying, there are fewer 6 figure salespeople that Oracle can keep. Doesn't mean he was never worth his former salary. Doesn't even mean only the good salespeople are left. Perhaps his particular area was hit harder.

<comment><USER8> > "If we exclude the 'blame the economy' explanation..."

<comment><USER9> ...we can conveniently blame him entirely for his current predicament.

</comment></comment></comment></comment><comment><USER7> At 25 dollars a day for a hotel room, with food, a car lease and a storage unit to pay for and paying for bottled water he's spending even more than I am on living expenses and I HAVE a job.

Yes, some parts of the country are more expensive than others and by strict definition he's 'homeless', I don't think that term applies in the same way to somebody who has a storage unit full of vintage wine and flat screen TV's.

I don't take issue with people living however they see fit, but come on, I'd love to drive a BMW but I buy clunkers with _cash_ because that is what is practical. Don't expect me to feel sorry for you because you chose to make car payments and buy bottled water instead of paying your mortgage.

</comment><comment><USER10> Is this for real or did I just read an article from the Onion?

</comment><comment><USER11> I'm struck by how much of the time in this article is spent driving relative to how much is spent building stuff. Maybe that is just the OC Register reporting selectively. I really hope so.

He's apparently a well-educated professional recently making six figures and yet he is spending time on the job boards, waiting by the phone, and Tweeting, for more than a year and a half now. What the heck. That's stupid when you're 22, but you're excused a little stupidity when you're 22 and still think that job seeking is a matter of sending out resumes. When you're forty-something that is practical criminal.

<comment><USER12> Not everyone is a machiavellian networking pro. Some people just show up, do the job, and go home.

<comment><USER11> While I suppose it is theoretically possible to be an employed professional for the last two decades and earn six figures without ever once having explicitly done networking, it seems like he probably has a lot of free time now and there is no time like the present to start calling up all the people whose lives he has touched in the last two decades and catch up on what their current needs are.

<comment><USER13> If he's been at the same job for two decades, and _especially_ if his company doesn't explicitly do work for clients (most programmers work on in-house code, doubly true for those making six figures), most of the people whose lives he's touched are either still at that company or out on their asses as well. And the ones that have found new jobs are probably too new at them to be of much help getting his foot in the door.

Also, there are some _severe_ hiring stigmas against older programmers. Now, early 40s is not what I'd consider "old" by any realistic metric, but I know expert coders in that age bracket that have serious trouble finding jobs because of the overqualification issue (i.e. that a programmer fresh from school can usually meet the company's needs, but the company can pay them half as much because they have no experience), as ~15 years in the biz tends to put one into the senior developer bracket.

Of course, one important question is whether this guy is even _considering_ jobs that pay in the $40-$60k range; I find it hard to believe that there are no medium to low range programming jobs that he can find, at least if he's any good. It's very possible that he's looking in all the wrong places because he considers himself too valuable, having been spoiled by six figure salaries until his laying off...

Then again, it's also possible that his specialty was too niche for him to be highly employable outside his company, like if he was primarily maintaining some legacy system written in Cobol? (which would be a dealbreaker on a resume at plenty of places...) Some of the coders doing that type of stuff make _tons_ of money when they work because nobody programs goddamn Cobol anymore, but they have a hell of a time finding new jobs when the old ones disappear.

Edit: nevermind, just saw a tweet of his: "Anyone looking for a Sr Financial Analyst/Corp Dev/Planning person in OC or Bay Area please let me know." This guy's not looking for programming work at all, so everything I said is mostly irrelevant...

</comment></comment></comment></comment><comment><USER14> Arg, if anyone deserves to be homeless its the IT guy running the ocregister's mobile site.

Accessing this link from an Android it redirects to a broken gateway page, which in turn links to tbeir mobile front page, completely losing the original link.

Still boggles my mind that a site can be so fucked up. Ironic thing is if they just left it alone and didn't try to be all fancy with the user agent parsing, things would have been fine.</comment>


Naja Pitches on Shark Tank - <AUTHOR> https://www.youtube.com/watch?v=yL11e1eJ2mk

<comment><USER2> I think she gave off an arrogant feel. The sharks didn't like that she acted like she was smarter than everyone. When she said that she met the VC at a bar.. my immediate thoughts were related to all those stores of women claiming sexual harassment issues when meeting with VC's.. but the opposite.</comment>


Best DigitalOcean Alternative - <AUTHOR> http://getvps.ninja/2015/05/best-digitalocean-alternative

<comment><USER2> At least be honest, you just want to make some money, and don't really have a clue whether it is a good alternative or not. :)

<comment><AUTHOR> Is my honest opinion and experience, trust me! And some money can be good too :)</comment></comment>


A Quantitative Approach to Product Market Fit - <AUTHOR> https://tribecap.co/a-quantitative-approach-to-product-market-fit/ <comment><USER2> This seems more like a companion article to David Skok's SaaS Metrics 2.0:

[https://www.forentrepreneurs.com/saas- metrics-2/](https://www.forentrepreneurs.com/saas-metrics-2/)

I found it to be more about SaaS metrics and less about product/market fit.

For example, you could have great product/market fit with poor pricing, in which case you might have awful SaaS metrics and sluggish revenue growth while having great usage metrics and rapid organic/viral user growth.

For example, imagine if PagerDuty or Slack were free for enterprises: they'd have terrible SaaS metrics but wonderful product/market fit, IMO.

<comment><USER3> If you give something away for free do you really have product/market fit? If you continue this sort of thinking by giving every user $100 you can make every product a huge success with massive viral growth.

Sustainable product/market fit is rare, the fake kind can be easily bought by selling a dollar for 50c.

<comment><USER4> Isn't this what Uber and Lyft have done? They've been selling dollars for $.75 and still have not proven they have a market at sustainable pricing as far as I know. Meanwhile they have a market cap greater than the big three US auto makers combined.

<comment><USER3> That is certainly the suspicion. In the end, like gravity, reality always wins.

</comment></comment></comment></comment><comment><USER5> Interesting, but seems pretty complex. I prefer the model employed by Superhuman: [https://firstround.com/review/how-superhuman-built-an- engine...](https://firstround.com/review/how-superhuman-built-an-engine-to- find-product-market-fit/)

Yeah I know, they're the joke of last week, but that methodology is pretty simple (just ask four questions) and (importantly) is trackable over time, while working for businesses of all kinds.

Is anybody else using that at the moment? How has it worked out?

<comment><USER6> I like that approach. To me the essential question of product-market fit is whether you are delivering sufficient value to your users. But I think "sufficient" has at least three characteristics that one can measure.

One is whether the user likes it enough to keep using it. I think that's well captured by the "how disappointed" approach (and actual usage stats). Another is whether they'll be evangelical about it, and I think that's measurable with Net Promoter Score (and actual viral behavior). And a third is whether you can build a sustainable business, which early on can be pretty simple, but eventually requires a fairly complex numerical analysis.

I think a numerical approach like this one is especially valuable if the business isn't self-funding. Because a) you need to be able to prove the value of the equity you're selling, and b) if you don't price your equity properly, it's just a gift to the VCs who do that work.

</comment></comment><comment><USER7> Interesting, but this seems more suited for subscription-type software businesses, not anything related to products with longer periods between repeat purchases. You'd have to wait for a couple of years or more to build out churn/resurrection/expansion, etc. and cohort data for a hardware or durable goods business. No wonder VCs don't really like to fund hardware/infrastructure businesses

</comment><comment><USER8> metrics are helpful, but creation is art</comment>


This is what a social-network exodus looks like - <AUTHOR> http://nostrademons.livejournal.com/friends

<comment><AUTHOR> This is time-sensitive, but as of 2:00 AM PDT Saturday, only _one_ out of the 8 most recent entries on my LiveJournal friendslist is _not_ about Dreamwidth. There are many other friendslocked or older posts also saying "I'm moving to Dreamwidth; find me at xxx."

I posted this because there is a persistent belief among technorati that social networks benefit from large network effects that prevent users from switching, even if the underlying software sucks. When I've said "No, users just use the social network as a venue to tell everyone where to find them, and then whole groups of people migrate en masse," people have asked me "Well, do you know of any cases of this actually happening." Well, here's one.

This is not unique at all - LiveJournal has had persistent problems with whole cliques of users splitting off to form other sites, eg. JournalFen, Plogs, uJournal, and GreatestJournal, because of the ease of forking their codebase. Hacker News started largely as dissatisfied Reddit users moved to a site where the quality of debate was higher. FictionAlley started after dissatisfied users migrated en masse from Fanfiction.net.

<comment><USER2> So the smart social networks create lock-in. Here're a few things Facebook does (all of which are smart and some of which were probably not done solely for lock-in).

1) Encourage the uploading of lots of pictures without an easy way to download them again in a batch. Same thing goes for chat and mail messages.

2) Encourage high friend counts via the friend suggestion tool so that a small number of friends leaving as a clique have minimal impact on your overall experience.

3) Hide the defriending process so you aren't notified when friends leave the service. In fact the news feed, has so much in it now, you probably wouldn't notice anyone's absence even if they did notify you. You'd probably not see a "goodbye" group half your friends were joining, either...

Which is to say, Facebook may retain users a little better than Livejournal.

<comment><AUTHOR> LiveJournal has all those too:

1) In most cases, these people have _7 years_ of accumulated journal entries, all tagged and memory'd, which is a significant chunk of their life. And these are harder to get at than FaceBook photos, because you typically write a LJ post directly into the browser, yet you upload photos from your computer. I dunno about you, but I keep a backup of every photo I send to FaceBook.

2) Ditto LiveJournal via communities, at least among this user base. I've got 200+ friends on LJ, though most are inactive, having moved to FaceBook when they went to college. Some of the people in question have hit the LJ technical max of 500 friends (I think this is now 750, largely because of their complaints). Instead of their high friend counts preventing them from leaving, though, it makes the impact worse. They act like "superconnectors" in _The Tipping Point_ , spreading the word to lots and lots of their friends.

3.) The defriending process on LiveJournal is also silent; it happens to be noisy here because people _announce_ that they're leaving (which they can do on FaceBook too, through shared links, wall posts, status messages, etc.)

I think that the real reason FaceBook hasn't seen an exodus is:

a.) As mentioned elsewhere, they're really not that bad a site. FaceBook still actively develops the code, they've got a real corporate communications department, and they're basically a "serious business". That prevents them from making the sort of pissing-off-users fiascos that LJ has been plagued with.

b.) They've tried very hard _not_ to cultivate passionate users. FaceBook users basically use it as a utility to keep track of friends and don't think too much about it, so when they leave, they just stop using it and don't try to convince all their friends to leave with them. While LiveJournal users tend to let their lives get very, very wrapped up in LiveJournal, so they have a large emotional investment in it and get very upset when that investment is betrayed.

</comment></comment></comment><comment><USER3> We all* know about bars/clubs/etc. that went from being THE place on X night to closing up in a matter of three or four years. The local paper (Cleveland) featured an interview with a club owner who was closing up a location that, only three years earlier, was a favorite spot of LeBron James and was packed several nights a week. Instead of complaining about his change in fortune, he proposed that this is the natural cycle of the club scene. As places get more popular, they become less exclusive and convey less social status on their patrons. So, those people with the most social status are courted elsewhere, and the masses again follow. The cycle repeats.

Freakonomics noted that baby names are usually introduced by wealthier folks and later adopted by poorer people. At that point, they are shunned by the wealthy.

Is there a reason that social networking sites should not exhibit similar patterns? Quite a few articles have been written about how the cool kids went to FB first. Are we simply witnessing the expected?

* Even if you hate going to these places, you probably are still aware of them.

</comment><comment><USER4> Let's not forget the Friendster exodus. That was pretty extreme.

<comment><USER5> The Friendster exodus wasn't _to_ anywhere tho'. People just stopped using it. Facebook came along later.

<comment><USER4> I don't know the numbers but my understanding at the time was that many people went to MySpace and later settled on Facebook when it came out.</comment></comment></comment>


Microsoft Edge Preview for iOS and Android - <AUTHOR> https://www.microsoft.com/en-us/windows/microsoft-edge-mobile <comment><USER2> I find this so very weird as I remember the days when Microsoft locked their users into msft only solutions. Now we have msft competing on interoperability, while Apple is the new monopolist that ties their customers down to locked in environment.

I suppose this is evidence that governments should be more quick to interfere with the free market if a monopolist is playing unfair.

<comment><USER3> Apple is not a monopolist. iPhone marketshare is ~15% globally. There is plenty of choice.

<comment><USER4> I think what the comment was trying to say is that there is only one way to get an Apple experience and that's to buy Apple products.

For example, I can use Office on my Mac while I can't use Pages/Numbers/Keynote on my Windows desktop.</comment></comment></comment>


One-Hour Mandelbrot: Creating a Fractal on the Vintage Xerox Alto - <AUTHOR> http://www.righto.com/2017/06/one-hour-mandelbrot-creating-fractal-on.html <comment><USER2> I still remember the day I read the article on the Mandelbrot set and went, "Whoa, I understand the math!"

I went on to write my first Mandelbrot renderer in Python. I was delighted, in a way, that it worked, but badly disappointed at the performance.

I rewrote the thing in C, and then rewrote it again to make use of multiple CPU cores. I am certain there are Mandelbrot renderers out there that put mine to shame. But still, it was fun, and I got some pretty desktop wallpapers out of it. And I learned a thing or two along the way. Also, I rewrote it again using PVM (Parallel Virtual Machine) to spread the work out across several computers. So I actually learned two or three things along the way. ;-)

In a previous job, I had a supervisor who learned programming in the mid-80s who told me about rendering the Mandelbrot set, then using bit-twiddling on the VGA memory to change the color palette on the display. I was not sure if I should be envious to have missed those times or happy.

<comment><USER3> yeah, once z = z __2 + c was explained, most of Mandelbrot was easy for me too.

I tried it in BASIC on an Apple IIe. it was the first time I was confronted with the question of whether it was safe to run the computer over night, or if it would overheat.

The next morning, the computer was fine, but it still hadn't reached an interesting part of the set.

So once I got a PC I ended up using Fractint. In those days, Intels had slow floating point, so they ported the algorithm to use integer. That was much more effective than jjust speeding up the machine clock (my first learning about performance).

Palette cycling was "cool" but by the time I got to college, while I thought I'd spend all my time generating fractals, I found the real world more interesting...

</comment></comment><comment><USER4> The first Mandelbrot generator I played with took more than 3 hours on a BBC Micro to render a 160x256 image. That was 30 years ago and I still try out variations on this from time to time (larger exponents, fractional exponents, complex exponents, animations, etc).

[http://alquerubim.blogspot.com.br/search/label/Fractais](http://alquerubim.blogspot.com.br/search/label/Fractais)

<comment><USER5> … while in the same era Peitgen and Richter were publishing books with detailed Mandelbrot sets in full-colour plates. What computers were _they_ using?

<comment><USER6> They reference IBM labs. _The Beauty of Fractal Images_ talks about an IBM 4361-5 with extended precision, and an IBM 4250 printer for one of the monochrome plates near the end of the book.

 _The Science of Fractal Images_ lists, as credits for the colour plates, these people and institutions: [http://imgur.com/a/KSnDZ](http://imgur.com/a/KSnDZ)

<comment><USER7> A cousin, the 4341, was my first mainframe. That was the first time I was exposed to the concept behind pg's "beating the averages article": at a time most of my colleagues were writing dBase or COBOL code, I interned with people using Cincom's Mantis. It was the Rails of the 3270.

</comment></comment></comment></comment><comment><USER8> For anyone on iOS, I recommend you check out the app Frax. Created in part by the Legendary Kai Krause!

[http://fract.al/](http://fract.al/)

Realtime, 60 fps, incredibly beautiful fractals on iPhone and iPad. (am not affiliated with them, just a fan)

<comment><USER9> If you're not feeling so artistically inclined - or maybe just burned out on the Mandelbrot set - you can get a "flame" fractal image or video every month from a guy I know who does them professionally. [https://www.patreon.com/QuinnPalmer](https://www.patreon.com/QuinnPalmer)

<comment><USER9> Super late edit - it's several wallpapers per month and one video. Also you can get physical objects with the designs on them through his kinda-defunct old site [http://fractal.world/](http://fractal.world/)

</comment></comment></comment><comment><USER10> Reminds me of writing programs to map the Mandelbrot and Julia sets onto the display of my Kaypro 2X. Didn't even have real bitmapped graphics -- just a way of packing... I think it was 4-pixel squares, into a character representation and then writing that.

Similar to packing up bits to characters shot to some sort of dot matrix printer attached to VAX, to print out such images, a couple of years earlier. At least that generated the images more quickly.

The Kaypro 2X was long in the tooth, by that point.

I wonder whether it will still fire up?

<comment><USER11> There's a "mode" if you will, on CGA cards, that involves something similar - best explained here:

[http://8088mph.blogspot.com/2015/04/cga-in-1024-colors- new-m...](http://8088mph.blogspot.com/2015/04/cga-in-1024-colors-new-mode- illustrated.html)

If this hasn't already been featured on HN, I'd be surprised...

</comment></comment><comment><USER12> "You can also see the CPU's registers on this board." That made me LOL a bit. Very interesting architecture.

<comment><USER13> I've come to understand that many CPUs were not single-chip, well into the integrated circuit era. Today we might assume that a microprocessor will come in a single package, but that wasn't a reasonable assumption in other decades, where the computer designer might even be creating the CPU as well, and not have access to a semiconductor fab.

<comment><USER14> It's surprising to me how in the 1970s, if someone needed a processor for something (even a video game or CNC controller), it was normal for them to invent a new instruction set and put together a processor from TTL chips. The barrier to entry was very low.

<comment><USER15> >...put together a processor from TTL chips. The barrier to entry was very low.

It was mostly because of the clock speeds, wasn't it? I seem to remember once hearing that below 20 Mhz you could play "TTL Lego" but above that you ran into problems with things like propagation delay.

<comment><USER13> The stated propagation delay for TTL chips was usually about 10 or 20 nanoseconds (sometimes larger for more complex logical operations, and frequently smaller in subsequent logic generations, like 5 nanoseconds or so). I just checked this in a late 1970s databook.

So, 20 MHz seems pretty credible for a region where you would see problems due to propagation delay—maybe even somewhere below that with the original 7400 series.

That's also a reason that I hadn't thought about so much why putting the whole CPU on a single die would look more and more practical over time: propagation delay in wires!

</comment></comment></comment></comment></comment><comment><USER9> And now my crummy laptop can render a smooth-shaded version full-screen at 12 FPS. [https://www.shadertoy.com/view/lsX3W4](https://www.shadertoy.com/view/lsX3W4)

<comment><USER16> And it does that with a brute-force algorithm. Try xaos, it can render much faster using ONLY THE CPU

</comment></comment><comment><USER17> I wonder if a more efficient microcode could be written for the Alto to optimise just for rendering Mandelbrot sets

<comment><USER14> The Alto has up to 3K RAM to hold custom microcode, and some programs used their own microcode for performance. So, yes it would be quite possible to speed up the Mandelbrot set with microcode. But writing Alto microcode is very difficult, so I'm not planning to do that...

</comment></comment><comment><USER7> It wasn't much faster on the Apple II...

Even though its BASIC interpreter used a 40-bit float, that I was downsampling the resolution to get 64-ish dithered colors, and that it was compiled down to mostly ROM calls, it took a very long time to render regions, in special those closer to the set itself.

Ok. As clock-efficient as the 6502 was, it still ran at 1 MHz.

</comment><comment><USER8> An amazing demonstration of the math behind some fractals, which runs on web gl, is Steven Witten's "How to Fold a Julia Fractal"

[https://acko.net/blog/how-to-fold-a-julia- fractal/](https://acko.net/blog/how-to-fold-a-julia-fractal/)

Highly recommended

<comment><USER18> I recommend these too:

Coding Challenge #21: Mandelbrot Set with p5.js - [https://www.youtube.com/watch?v=6z7GQewK- Ks](https://www.youtube.com/watch?v=6z7GQewK-Ks)

VEX IN HOUDINI: MANDELBROT AND MANDELBULB - [https://www.sidefx.com/tutorials/vex-in-houdini- mandelbrot-a...](https://www.sidefx.com/tutorials/vex-in-houdini-mandelbrot- and-mandelbulb/)

The second link is Houdini specific but you should be able to follow along with the free version on win/linux/osx.

</comment></comment><comment><USER19> I remember writing Mandelbrot on C64 and Amigas. Depending on depth you could wait some time. So it often was overnight, with a pleasunt suprise the next morning (or some ugly looking picture)

</comment><comment><USER20>
        On a modern computer, a Javascript program
        can generate the Mandelbrot set in a fraction
        of a second, while the Alto took an hour.

Hm... a "fraction" could mean anything. If it's exactly a second, then the speedup factor would be about 3600x.

The Alto was built about 40 years ago, right? That would be 30% performance improvement per year. Is that about right for single cpu performance acceleration over the last 40 years?

<comment><USER21> Well with this[0] implementation[1] my laptop can render 3840x2400 pixels at 60fps, so ignoring the larger resolution, so how about 1/60th of a second?

[0] [https://news.ycombinator.com/item?id=14588789](https://news.ycombinator.com/item?id=14588789)

[1] Is using a GPU cheating? Are we comparing computer performance or CPU performance? The Alto didn't even have a CPU as we know it today...

<comment><USER20> [1] Well, a GPU is somewhat geared towards this kind of workload. Both comparisons (Alto to modern CPU and Alto to modern GPU) have some meaning.

</comment></comment></comment><comment><USER22> With the limited computing power, they should have at least used the bilateral symmetry to halve the time.

</comment><comment><USER23> Nice, just a bit disappointed it was in BCPL and not Mesa.

<comment><USER14> I'm working on getting Mesa and Smalltalk running on the Alto, so stay tuned...

But BCPL is actually an interesting language. I knew that it influenced C (as did Algol and other languages), but until using BCPL I didn't realize how much of C was really the same as BCPL.

<comment><USER24> BCPL is almost a predecessor to C. The 8 bit micro that I used had a BCPL compiler for it.

[http://www.computinghistory.org.uk/userdata/images/large/PRO...](http://www.computinghistory.org.uk/userdata/images/large/PRODPIC-9770.jpg)

That was a nice stepping stone to C on the Atari ST.

<comment><USER25> It wasn't "almost" a predecessor to C, it was a direct predecessor.

<comment><USER23> There was B in between, which was Ken's attempt to a BCPL compiler, even the language's manuals look quite similar.</comment></comment></comment></comment></comment>