Open Source ARM userland - <AUTHOR> http://www.raspberrypi.org/archives/2221 <comment><USER2> This is not really open source, just a dump of boilerplate code that is of no real value to any hackers. It serves as a good PR stunt but is not really of any technical value.

I write software for ARM system on chips for living so I was naturally interested in what would a competitor's software stack look like. And I was very skeptical that they would have actually revealed anything of importance. And, unfortunately, I was right. There's nothing important here (at least in the 3d part).

The OpenGL implementation is still somewhere in a binary blob that is not accessible.

The graphics drivers would reveal crucial information about the hardware design and give an advantage to the competitors who can use that information and the software itself to make chips cheaper.

I'm not talking about established competitors in the high end market but the anonymous small chip companies that do chips for the $100 Android tablets you can get from Asia.

Note: I would really like that everyone in the SoC business would open source everything they had and and the competition would be about who designs and manufactures the badassest silicon chips. But that's just not the way it works and I can't do anything about it.

<comment><USER3> I disagree strongly. The value is that if APIs change (which they will), the drivers can be ported forward. Unlike all those poor routers stuck on Linux 2.4 forever, Raspberry Pi can now be maintained by the community.

The purpose of open source isn't always to learn. Sometimes the purpose is just to _make your computer work_.

(It's interesting that hackers were opposed to softmodems and such for many years but now people are taking the opposite stance in this thread.)

</comment></comment><comment><USER4> Wow, this is big. Embedded vendors are particularly precious about their GPU drivers.

Hopefully this is the start of a trend.

<comment><USER5> Well maybe - [http://www.phoronix.com/scan.php?page=news_item&px=MTIxM...](http://www.phoronix.com/scan.php?page=news_item&px=MTIxMjU)

<comment><USER6> From what I can see in the referenced talk, Samsung will still only provide binaries for the graphics.

<https://www.youtube.com/watch?v=LyYXh1V8ov8#t=30m40s>

<comment><USER5> That's a shame. It's something at least...

Binary drivers or binary GPU firmware? If the latter then Pi is in much the same place. (I would watch the video but am at work...)

</comment></comment></comment></comment><comment><USER7> I'm curious how much of the OpenGL stack lives on the GPU. Does anyone know how low- or high-level the interface to the Videocore is? (Yes, I could just dive into the official source code release and the unofficial reverse engineering project, but that would be an inefficient use of potentially hours, when someone in the know might be able to answer in minutes)

<comment><AUTHOR> The GL calls are marshalled across to the VideoCore firmware. The VideoCore firmware has essentially a function for each GL entry point. The shader compiler is in the VideoCore firmware. The QPU code fragments are generated by a pull on a data flow representation in the firmware.

<comment><USER7> Thanks! I suppose that's not too surprising; I've yet to hear of anybody open sourcing their core OpenGL implementation (is there even an open implementation other than Mesa?). It would be fun, in a sense, to have raw access to the VideoCore components without any existing firmware. Judging from this comment[0] of yours that I found on a Google search, I'm not the first to think so.

Now, as I've said before, if the RPi gets solid USB host and isochronous transfer support (for e.g. Kinect, USB audio devices), then it will be unbeatable.

[0] [http://www.raspberrypi.org/phpBB3/viewtopic.php?f=33&t=6...](http://www.raspberrypi.org/phpBB3/viewtopic.php?f=33&t=6188&start=50)

<comment><AUTHOR> It's possible to splice into the current blob by using /dev/mem to access the GPU partitioned memory. This lets you hot patch the VideoCore firmware (quite tricky as its running ThreadX OS), or you can hunt down QPU fragments generated by shaders.

I have a plan to release an Architecture/Programming guide and will be recruiting more hands shortly for tools like LLVM etc. But today let's celebrate the great work the foundation have done opening up the user land!

<comment><USER8> Just commenting to say thanks for working on this. A barebones open source firmware would be very cool to see.

</comment></comment></comment></comment></comment><comment><USER9> I think everyone who announces that their hardware is "fully open-source" should answer the "Stallman test".

That is, answer the question "Would Stallman use this?".

<comment><USER10> Instruction set is licensed, fails instantly!

</comment></comment><comment><USER11> Thanks for using BSD license so everyone can benefit.

</comment><comment><USER12> > Aside from being exciting to FOSS enthusiasts for philosophical reasons

Freedom is not a philosophical reason.

<comment><USER13> Philosophical doesn't mean arbitrary.

<comment><USER12> "Philosophical" means related to wisdom or knowledge. Philosophy inquires about the nature of things and the boundaries of nature itself.

In that sentence, «philosophical reasons», philosophical meant abstract, remote, detached from practical concerns. The freedoms sought by FLOSS people are very much practical (see <https://www.gnu.org/philosophy/free-sw.html> ) and with many concrete effects on your daily life. Engineering problems (problems with your video driver? Want to update the OS of your 2-year old tablet?) and social problems (ever heard of somebody whose books have been deleted remotely by a FLOSS app?).

<comment><USER13> You are mostly referring to epistemology and ontology, two rather theoretic branches of philosophy that probably aren't that relevant to software. The philosophy of free software (even your URL contains the P-Word ;)) makes use of ethical arguments and political philosophy, for examples the ideals of enlightenment. The age of enlightenment was kickstarted by philosophers, some of whom went to prison for clearly voicing thoughts that seem quite common to us today.

I want to argue that, while modern academic philosophy may be a bit of an ivory tower, philosophy in general isn't synonymous with "detached from practical concerns".

<comment><USER12> > philosophy in general isn't synonymous with "detached from practical > concerns".

I strongly agree with you on this; I did not make my point clear enough. What I do not like is the use that the article's author did of the term "philosophical". I do not think that philosophy is synonymous with "detached from practical concerns" but it feels like the author of the article do:

> Aside from being exciting to FOSS enthusiasts for philosophical reasons, > it's also going to make it much easier for third party developers to (for > instance) implement Wayland EGL client and EGL server support, or to provide > better integration of GLES/VG with X.Org.

To me it reads like "Aside finally shouting the mouth of these FOSS do- gooders, this change has practical positive implications". As if the people pushing the FOSS philosophy where not doing that because of their interest in practical (long term) benefits.

</comment></comment></comment></comment></comment><comment><USER14> Well, that was unexpected. Bravo!

<comment><AUTHOR> [http://www.h-online.com/open/news/item/Raspberry-Pi-opens- it...](http://www.h-online.com/open/news/item/Raspberry-Pi-opens-its-ARM- graphics-code-1735262.html)

Has some more details.

</comment></comment><comment><USER5> OK good, now the blob?

<comment><USER15> This is a pretty dumb request. What are you going to do with a chunk of bits for a processor for which you don't even have a toolchain. There is nothing more to open source other than what is already there.

Asking for 'the blob' is akin to asking for the firmware source to a hard disk. Even if you had it you could not do much with it.

<comment><USER7> Though I agree that the parent comment was unhelpful and a bit ungrateful, there is at least one good reason to want source code, _especially_ for one- of-a-kind GPU processors. It's just plain _interesting_.

 _Asking for 'the blob' is akin to asking for the firmware source to a hard disk. Even if you had it you could not do much with it._

Play. Is that not enough? I'd love to experiment with hard drive firmware, toy with different caching algorithms, learn about the algorithms that convert between the analog signals at the heads and the data sent to the host, etc.

</comment></comment></comment><comment><USER16> What does the "userland" subset encompass? What's left in closed source blobs?

<comment><USER17> AFAIK everything that runs on the ARM is now open source. The firmware of the GPU itself could still be a blob. That's very cool, I hope NVidia follows suit _wishful thinking_.

<comment><USER18> Thanks to Nouveau reverse engineering, you can actually run a number of recentish OpenGL GPUs with a completely open source stack including even the GPU firmware itself.

Now, I guess NVidia could put a high-powered processor on their GPUs and move their entire OpenGL driver stack onto it as "firmware" so that they could claim their drivers were open source, but that doesn't seem like something they'd do.

<comment><USER17> I certainly know about Nouveau. I even contributed to it, albeit indirectly (I'm the guy that wrote decuda). But reverse engineering GPUs is a thankless process, which has to be repeated for every new release of the hardware (in a certain sense, even for every stepping). Of course the tools are better these days so a part of reverse engineering can be done automatically, but still...

And sure, having the userspace and kernel driver open source is only a start. But having everything that runs on the CPU open source is great from a separation-of-concerns perspective.

Open sourcing the firmware and even the hardware itself would be cool, but is a battle for another day... And that'd no more be a matter of the just the GPU, but of all hardware that has firmware, including the CPU, network equipment, 3G radios...

</comment></comment></comment></comment><comment><USER15> The raspberrypi looks better every day. The last major item on the to-do list appears to be the supply side.

<comment><USER19> Even the supply is getting better. They have been increasing the production rates and the delivery timings are getting shorter.

<comment><USER20> Just wanted to mention that the supply from Element 14 in Australia is outstanding. I put in an order for 2x model B's two weeks ago and received them both (512mb model) last thursday ... approx. an 8 day wait.

<comment><USER21> I actually got my Pi from Element 14 Singapore in just two days. I'm surprised when I got the package. Maybe it's because the demand in my area (Hong Kong) is low.

</comment></comment></comment></comment><comment><USER22> Although this is good news am I correct in assuming the boot loader is still closed source? I was hoping that this would enable an official OpenBSD port but if the boot loader is still closed source this probably won't happen.

</comment><comment><USER23> To all those complaining about computers becoming "too closed", remember this.

What a fantastic amount of work that this must've required.

</comment><comment><USER24> Wow, that's huge. Can't wait to get hacking on processing and openframeworks. Being able to do real accelerated computer vision stuff with the Pi will be slick.

</comment><comment><USER25> Does it mean that we will soon see many cheap arm based computers built in China? (Similar to android effect)

<comment><USER26> You mean like all the Allwinner boards? Closest you're going to come to the price is ~50USD. I doubt the Chinese have the VideoCore GPU available to them (they use Mali) so, no.

My hope is that it would at least get ARM to open up more of the Mali stuff, but based on my interpretation (and experience) there is nothing extremely special between this announcement and every other ARM board. The meaty GPU bits that are the really fun and interesting bit are still locked away in a firmware blob.

</comment></comment><comment><USER27> No shader compiler => lame.

</comment><comment><USER28> good source.

</comment><comment><USER29> With such an open stack, could the Pi be used as part of a GPU password cracking cluster?

<comment><USER23> An exceedingly slow part. Ten Pi units together costing $350 would be absolutely dusted by a single $350 full-scale GPU.

A $350 video card would have upwards of 2000 shaders and would run at a much higher clock-speed. It's simply orders of magnitude faster at a price that's only one order of magnitude higher.</comment></comment>


Linode is being DDoS'ed in Dallas - <AUTHOR> https://status.linode.com/incidents/75jr6z6mr0cj <comment><USER2> Yet again, another DDoS. Is this an specific client this time or the target is Linode itself?

</comment><comment><USER3> Showing no impact across our ~20 servers hosted in Dallas right now.

Mailgun is having issues right now as well... coincidence? does Linode & Rackspace both use the same DC provider?

Edit: Starting to see some latency spikes [http://tomschlick- screenshots.s3.amazonaws.com/4TUUOeQh](http://tomschlick- screenshots.s3.amazonaws.com/4TUUOeQh)

</comment><comment><USER4> they seem to be DDoS'ed often.. how many incidents has it been over the past few weeks? :\</comment>


Memristors' one-year delay will hit IT in the wallet - <AUTHOR> http://www.zdnet.com/memristors-one-year-delay-will-hit-it-in-the-wallet-7000000586/ <comment><USER2> This is a stupid article. The author makes the assumption that HP and Hynix COULD ramp to high volume production, however it is clear from HP's statement that this is not true:

"As with many other ground-breaking technologies being developed at HP Labs, HP has not yet committed to a specific product roadmap for memristor-based products,"

Let me also say that I worked in the non-volatile memory business for seven years. Any organization that can scale better than its competitors will do so, unless they don't like making money. End of story. If HP and Hynix are not ramping to high volume, it's because they are not ready, not some stupid conspiracy theory that they want to stagnate the development of cloud-buzzword "technology".

<comment><USER3> Ah, a breath of fresh sanity from someone who knows the industry. That is very welcome, thank you.

The semiconductor industry is brutal in general. Selling to consumers is worse, but the worst by far is the part that sells any type of memory. Forget the conspiracy theories. This space is full of dead companies. Someone will eat you.

<comment><USER4> > _The semiconductor industry is brutal in general. Selling to consumers is > worse, but the worst by far is the part that sells any type of memory._

Really? Because there have been all kinds of price-fixing scandals and accusations for the last 2 decades... Price fixing does not sound very cut- throat to me...

<comment><USER3> The only DRAM price fixing scandal that I know of is the one from 1998 to 2002 which gave the involved parties litigation on their backs up until 2010. If you know of any others, please let me know. Google did not turn up anything else.

Anyway, I want to explain why the DRAM world is brutal:

Here is the DRAM top 10 from 2006: <http://i.cmpnet.com/eetimes/seminews/2007/chart1_020107.gif>

And today the state is as follows: [http://www.electronicsweekly.com/blogs/david-manners- semicon...](http://www.electronicsweekly.com/blogs/david-manners- semiconductor-blog/2012/03/top-ten-less-2-dram-companies.html)

Samsung: Eating everyone Hynix: Almost breaking even Qimonda: Dead Micron: Making money Elpida: Bankrupt Nanya: Losing more money than it makes Powerchip: Barely alive with 0.1% market share ProMos: Has sold its fabs, soon to be dead Etron: Alive, but with less that 0.1% market share and 15 cent loss per dollar sold. Winbond: Now only in specialty DRAM

So, Samsung and Micron are doing well, Hynix is barely OK and the rest are sunk. Yes, I believe that the DRAM competition is fierce and brutal.

</comment></comment></comment></comment><comment><AUTHOR> Why on earth was my title replaced? Sigh.

 _Revolutionary memristors purposely delayed to prevent cannibalization of flash_

It's 100% accurate and more relevant.

<comment><USER5> It makes no sense to me.

What's the advantage of memristor-based storage, exactly?

If it's cheaper to make, then sell storage at a price that undercuts the competition but still makes a better profi.

If it's more reliable, then sell storage at a higher price with a better warranty.

There's no sensible scenario where memristors are ready to go but they don't want to sell any memristor products yet because it will hurt existing sales. Either they can make a better product, or they can't, and if they can't make a better product then the stuff simply isn't ready.

<comment><AUTHOR> It's the same price for double the storage, less power and likely more reliability.

[http://www.zdnet.com/blog/foremski/tha-amazing-memristor- bey...](http://www.zdnet.com/blog/foremski/tha-amazing-memristor-beyond- moores-law-and-beyond-digital-computing/1309)

They are probably delaying to get their profit out of existing investments in tool and die for their factories, as well as high inventories.

While all the manufactures are likely not in cahoots, it's probably like the airline industry where they look to the left and right and nod at each other and change fees right after each other.

Also notable how hard drive prices have not dropped even though supply is completely back to normal.

<comment><USER6> Storage can be as reliable as you want, you only need to throw parity at the problem. Flash is one of the most unrealiable technology today, chips are ofter rated at only 10000 writes before bit-errors, flash is used as storage today thanks to advanced Error-correction (ECC) algorithms. BTW spinning hard- discs also use ECC since many years ago but it is much less powerful.

</comment></comment></comment></comment><comment><USER7> I haven't seen any lab demonstrations of multi Mbit devices. Until we see that this is years away from production in my experience as a device physics researcher. All storage technologies so far have taken 10 years plus to have large market share and I don't see this as an exception.

</comment><comment><USER8> Could they not charge a premium price for memristors early on to prevent flash cannibalization and then bring the price down as they transition their output?

<comment><USER9> Thats what I thought too. I did think they were going to have a sufficient difference to flash that they would be able to compete in a different way. The HPC market is the classic start point.

However, I think there may be other reasons. Maybe they haven't worked out the connection architecture properly?

</comment></comment><comment><USER10> Does HP have patents here that would prevent others from introducing this tech? Or are they/Hynix simply the only ones with experience with the tech to pull it off? This is such a clear example of one of the fears spelled out in The Innovators Dilemma it isn't even funny.

Edit: whoops, mtgx says Samsung is also in this space, so it sounds like patents can't be an obstacle, or at least until the suing starts.

<comment><USER11> Oh really, Samsung is going to compete with them?

So let's speculate

1 - They delayed this because of manufacturing problems and want to save face

2- They really are that stupid and gave a competitor a 1 year head start (or they made a Gentleman's Agreement - but it wouldn't prevent even another competitor getting in)

In short, this is extremely risky.

<comment><USER10> 3) They feel they are far enough ahead of competitors that they can afford to "drain the pipeline of flash based products" and still come out ahead in memristors ultimately.

I agree a purposeful delay in order to try and squeeze some drops out of existing stock / sunk costs would be risky, and likely stupid. Clearly no corporation has ever made short-sighted, stupid decisions like that before so this would totally be a first :)

</comment></comment></comment><comment><USER12> [http://www.newscientist.com/article/mg21328535.200-online- sp...](http://www.newscientist.com/article/mg21328535.200-online-spat-over- who-joins-memristor-club.html)

It seems like HP still hasn't been issued patents for it (at least by my googling) so I guess they are happy to just sit on their tech.

Also, Memristors are already being actively used for military technology, most notable the SyNAPSE project.

</comment><comment><USER13> I'll believe memristor tech when I see commercial products of it available. I don't think it's far fetched that a company is slow to shift it's mainstay, profitable business product to an unproven new technology that has no mainstream commercial products out yet. Cutting edge tech is always rife with delays and shortcomings that weren't anticipated until the rubber actually hit the road.

While many in these comments are touting "double storage & reliability for the same price", that would be for raw manufacturing costs, not including all the R&D money and the cost of fabrication plants that must be built or retooled. It is highly unlikely consumers will see those benefits anytime soon.

</comment><comment><USER14> I don't see why this is a big deal. It's a year, so what? We've waited decades, a year isn't going to hurt anything. Hynix is a big business that is heavily invested in flash and it takes a lot to completely change the core of your business over, especially when you have to possibly build new fabs and fab technology.

<comment><AUTHOR> Double the storage space and possibly double the reliability for the same price?

Also potential power savings.

A year is a huge deal if someone was planning on spending a million on a datacenter to make it use SSD for database, etc.

<comment><USER15> Where do you get "for the same price"? I can assure you that even if memresistors cost 1/10 to produce the equiv in other tech they would hit the market at 10x the price. Better tech can get a higher price and as long as the ability to provide market demand is limited by patents or the cost to convert/build fabs then the supplier gets to set the price.

Seems like a lot of people in this discussion failed Econ 101.

<comment><USER16> Competition pushes the price of a product toward the manufacturing cost of a product over time.

</comment></comment></comment></comment><comment><USER17> Hynix (2nd largest memory chip maker after Samsung) and friends were fined just a couple years ago for price fixing memory, <http://www.bbc.co.uk/news/10126755>. If competition isn't a problem, why waste money on costly innovation?

Reminds me of Eastman Kodak circa 1975 <http://en.wikipedia.org/wiki/Eastman_Kodak#Shift_to_digital>.

That said, this is pretty weak evidence of collusion.

</comment><comment><USER18> This catchy headline is essentially saying that company X is going to watch their growth and expenditure and maximise their profits in a manner which won't benefit consumers.

The headline is interesting because it's stating the obvious, standard business practice but possibly they have hit on the only way to glam up the incredibly boring story of 'product will be delayed by 12 months'.

</comment><comment><USER19> What short-sighted thinking. This is why you don't see much innovation from the big companies usually. This is like Apple thinking they shouldn't release the iPad because it would cannibalize their Mac sales. Instead of being an also-ran in flash, Hynix/HP could be the leaders in memristors. But it seems you won't see them thinking like that.

Oh well, I guess Samsung will take the lead in that market, too, then, since I think they were the other main company working on memristors.

<comment><USER20> An LOL at "this is why you don't see much innovation from the big companies" followed by a what-if-Apple-did-this example. Apple is a big company. The biggest.

The article is B.S. If the release of this technology will replace all RAM, Flash memory, and other memory storage technologies as the author expects, they wouldn't need to delay it.

And lastly, if you believe the article, it says it's not in HP's control anyways. It's the manufacture partner Hynix fault.

<comment><USER4> > _An LOL at "this is why you don't see much innovation from the big > companies" followed by a what-if-Apple-did-this example. Apple is a big > company. The biggest._

And a LOL for misunderstanding his point.

He said that "this is why you don't see MUCH innovation from the big companies", not "why you don't see ANY" innovation.

And he used Apple precisely as a _counter_example_ to that lack of innovation, saying that what HP did would be like a hypothetical Apple saying they won't release the iPad because that would cannibalise iPhone sales.

</comment></comment></comment><comment><USER21> It only makes sense to continue selling the older, higher margin products until a competitor comes up. They are asking for it.

I would even root for Samsung on this (also because it just finished my laundry).

<comment><USER22> >It only makes sense to continue selling the older, higher margin products until a competitor comes up.

If you're the only one on the market with memristors the margin is determined by whatever the market will bear, and if they're really that much better than existing technologies it will be much larger.

None of this conspiracy stuff makes any sense. They're delaying a year because they can't manufacture the product.

</comment></comment><comment><USER23> When I first heard of HP's memristors, I was looking forward to them using it in the TouchPad, to really compete against Apple. Now this. FAIL all around, HP.

</comment><comment><USER24> This is worrisome:

<http://arxiv.org/abs/1207.7319>

</comment><comment><AUTHOR> This might also explain why SSD prices are dropping fast.

50 cents per GB now and falling.</comment>


Programming an HP-15C (2013) - <AUTHOR> https://blog.plover.com/brain/hp-15c.html <comment><USER2> I bought a 15C new. I still have it on my EE bench (replacing my slide rule, of course). Every 8 or 9 years I replace the three LR44 batteries. And writing little programs to tickle the Inner Nerd is always fun. HP: we miss you!

<comment><USER3> I have been using HP 42S for the past 15 years and would not replace it for any other. It is a pity that the LCD fades out in these and now it is only possible to see it at specific angles.

<comment><USER4> You may be interested by this [1]

The device is reliable, the screen is amazing, the USB connectivity brings a lot of value and the community on SwissMicros' forum are passionate HP people.

I'm not affiliated with them in any way, just an happy geeky customer :)

[1] [https://www.swissmicros.com/dm42.php](https://www.swissmicros.com/dm42.php)

<comment><USER5> Seconded. Their replicas are amazing, even better than the already awesome originals. I own a few, only god knows why :)

Maybe I'll ask to be buried with them, so I can be dug up in a few thousand years and worry archeologists ;)

</comment></comment></comment></comment><comment><USER6> I think the "someone who brought it back" is Swiss Micros, which makes a compatible calculator (which they call DM-15) as well as other models in the same family. They say their chip that emulates the original cpu is quite a bit faster than the original.

[https://www.swissmicros.com](https://www.swissmicros.com)

<comment><USER7> HP still makes a decent HP-15-like calculator:

[https://en.m.wikipedia.org/wiki/HP_35s](https://en.m.wikipedia.org/wiki/HP_35s)

<comment><USER5> The HP store shows many of their remaining 7 (!) calculator models out of stock quite often. I'm not taking any bets on how long HP is going to make any calculators at all. I feel sad every time I visit their store...

They already stopped making any kind of graphing calculator, apparently.

<comment><USER8> HP ported their calculators to iPhone and Android apps. Most people who want an HP calc probably just use those now instead, except for the few who want the tactile feel of calculator buttons.

<comment><USER9> For the discerning STEM student/professional, 15c is the only relevant RPN emulator on mobile officially released by HP and it's an overpriced disappointment IMHO.

HP didn't even extend a courtesy reach-around for our CS/CpE brethren with 16c integration despite their $16.99! Even if you were in the market circa 2011 to pre-order one (or a few) 15c LE--which came with a copy of the desktop app-- you'd still have to pony up even more for the mobile app!

On Android, I'd highly recommend skipping the "official" HP garbage and supporting CalcTastic Plus[1] for a mere $0.99. Even the free version makes the HP emulator look like a complete joke. I've been rolling with a 35s as workhorse since undergrad days, but couldn't care less if today's zombie HP literally disappeared from the market tomorrow.

[1] [https://play.google.com/store/apps/details?id=com.shaytastic...](https://play.google.com/store/apps/details?id=com.shaytasticsoftware.calctastic)

<comment><USER8> Good info, thanks for the update!

</comment></comment></comment></comment></comment></comment><comment><USER10> Wow that sounds a lot more complicated than the one I had, HP 42S, because you had to use codes for the instructions instead of just pulling up the instructions in readable ASCII.

I found this random example of entering a program on a 42S: [https://www.youtube.com/watch?v=JQMOOxup8bI](https://www.youtube.com/watch?v=JQMOOxup8bI) Coincidentally, it even uses the FP (fractional part) and X=0? test that the OP mentioned.

I wanted to see what programming the 15C looked like, so I found this as well: [https://www.youtube.com/watch?v=m4dF5nF8I88](https://www.youtube.com/watch?v=m4dF5nF8I88) Looks like you can enter the program without knowing the codes, but reviewing the code just shows codes.

<comment><USER11> The HP codes aren't too bad because they correspond to the location of the keys on the keyboard, i.e. y^x is 21 because it's the second row and first column of the keyboard. If you want something really confusing try programming a Soviet Elekronika calculator, they actually work fairly similarly to the HPs but the codes displayed on the screen when inputting a program are in hexadecimal displayed with weird symbols because you can't actually show A-F on a seven segment display.

<comment><USER12> I've typically seen A-F rendered like so:

       _         _        _   _
      |_|  |_   |    _|  |_  |_
      | |  |_|  |_  |_|  |_  |

(Variations would be a double-story lower case 'a' and lower case 'c'.)

<comment><USER13> But if they cloned the 7447 decoder they'd look like

                       _
         _    _   |_| |_   |_
        |_    _|       _   |_

with 15 blank.

</comment></comment></comment></comment><comment><USER14> Given how hard it can be for me to focus when the web is just one click away, these dedicated tools are such a boon. Plus the hacker touch of these programming languages has something lovely.

(I don't get what's so funny with the 38x3, though...)

<comment><USER15> Yeah - I'm not mathematically inclined enough to understand what would be so funny about the 38x^3 denominator either?

Unless it's something that would cause an error due to memory/register size constraints, or cause the calculator to sit there forever on some of the other larger squares or test values due to 1986 speed of the ALU or whatever is in the calc?

My gut assumption is that it's some mathematics inside joke of some sort...

<comment><USER16> All of the other constants are expected. 1, 2, 9, 10 ok those make sense. Where does 38 come from? Ha ha. So random.

<comment><USER17> I could not have put it better myself.

</comment></comment></comment></comment><comment><USER18> Related: it's been sad to see the HP48 emulators bitrotting. m48 is no longer available on the App Store, and I can't find anything that works anymore for the Mac.

<comment><USER19> There's a port of Emu48 to MacOS

[https://sourceforge.net/projects/emu48mac/](https://sourceforge.net/projects/emu48mac/)

Kinda Mac-related is i48 for iOS:

[https://apps.apple.com/us/app/i48/id329454950](https://apps.apple.com/us/app/i48/id329454950)

hpcalc.org has a list of emulators:

[https://www.hpcalc.org/hp48/pc/emulators/](https://www.hpcalc.org/hp48/pc/emulators/)

Best seems to be Emu48, as mentioned above:

[https://hp.giesselink.com/emu48.htm](https://hp.giesselink.com/emu48.htm)

x48 is open source, like Emu48:

[https://sourceforge.net/projects/x48.berlios/](https://sourceforge.net/projects/x48.berlios/)

<comment><USER18> Unfortunately I couldn't get any of em to build anymore. Emu48 is definitely the best, but it needs help to build on new MacOS. x48 doesn't build anymore, and is also X11 based, which is not great on Mac anymore either.

</comment></comment></comment><comment><USER20> I have both the HP15C and two HP16Cs, though I am not old enough to have bought one new. :o) Truly awesome calculators, even if they are a bit slow sometimes. The form factor of the Voyagers is amazingly perfect; in fact the ratio of the length to width is approximately the Golden Ratio if I recall.

I use mine regularly as I prefer a tactile instrument. Plus the mental challenge of implementing programs in a constrained environment is invigorating.

</comment><comment><USER21> Upvote because I still own and occasionally use my HP-11C. It may be on its 4th set of batteries, after 30+ years. I haven't written code on it for 20yrs, but the last was a sight-reduction program for celestial navigation. I do have and use emulation of HP-15C on every computer I cam, plus my phone.

</comment><comment><USER22> Oh, yeah, I wrote a Brainfuck interpreter for those [https://steemit.com/programming/@michaelzinn/babbage-s- diffe...](https://steemit.com/programming/@michaelzinn/babbage-s-difference- engine-in-brainfuck-on-a-calculator)

I also did a C64 BASIC compiler in Idris for it, if you have a copy with over 800 lines of program memory you can play HAMURABI on it: [https://forum.swissmicros.com/viewtopic.php?f=23&t=2193](https://forum.swissmicros.com/viewtopic.php?f=23&t=2193)

I strongly recommend that calculator, it's a great programming toy.

</comment><comment><USER23> I'm currently implementing a concatenative language, and have added OP's program as an example: [https://github.com/pflanze/copycat/blob/master/examples/hp.s...](https://github.com/pflanze/copycat/blob/master/examples/hp.scm)

This is closer to how the later HP models worked, where naming and quotations are available (via « »).

(I happen to have had an HP-15C as well as my first calculator :)

</comment><comment><USER24> I still have mine and the user manual sits on a shelf in my basement. I bought mine in a private deal from a guy whose father was a distributor. Cost me $110 in 1984. It allowed me to invert a 4x4 matrix, thereby earning me an A in my power engineering class. I programmed a sinc function to the amazement of my linear systems instructor. And I programmed complex multiplication and division routines. This was pretty cutting edge back in the day, long before mathcad.

</comment><comment><USER25> Reminds me to start collecting HP calculators. I have a few, but would like to collect all of them and put them in a display case. Anything non-RPN is an abomination.

<comment><USER26> Are you familiar with www.hpmuseum.org? Collectors and users of HP calculators hang out there. Hp41.org is great for the HP41

</comment></comment><comment><USER21> On a different note, I stumbled on my TI-Programmer LED calculator and power supply a few days ago. I plugged it in, but no response. I guess rechargable batteries weren't meant to last nearly 40 yrs. I am now obligated to attempt resurrection. In case I need octal, hex, or bit operations.

</comment><comment><USER27> I have an HP 200LX that I acquired recently. I have been using it for writing mainly, it's pretty fun. I also have an old PCMCIA Ethernet card that I want to use with the 200LX so I can connect to IRC (mainly for Twitch chat).

</comment><comment><USER28> I have one from my grandfather and one from my father. Amazing things. I wonder what device I should leave for my future children! Maybe my Ti-83...

</comment><comment><USER29> I use a magnificent HP emulator called nonpareil for almost all my RPN needs (the rest being covered by dc and xcalc -rpn).</comment>


The questionable value of the real-time web - Demand-side attention economics - <AUTHOR> http://danieltenner.com/posts/0013-real-time-web.html

<comment><USER3> Consciousness work by filtering information. The problem with the real-time- web is that it demands too much cognitive attention compared to what it was supposed to give us in return (always relevant information in context).

But It's importance cannot be underestimated. In a better world, augmented reality allows us to explore a reality with multiple layers and always contextually relevant information.

With that in mind though, the current state of RTW is the stone age and we are nothing but a bunch of slaves ploughing through an overwhelming amount of information in order to find something of importance that we can then share with others through some aggregator.

In a better world, we will still receive way to much information to ever process. But instead of scanning each post as a separate entity, the RTW will reflect an emerging alternate reality based on knowledge our needs.

Until then RTW will continue to include more and more sources communicating most of them automatically, but my guess is that they will be part of a soup of the augmented reality universe and serve to in the end create an alternative matter based on information. Allowing for the construction of the agumented layer.

There is huge start-up potential to figure out a way to filter information in a way that allows for all sorts of information to pass through without any of it being more important, but where it together will create an alternative reality.

I would think that the next feature that aggregator will need to look at it a better filtering only surfacing things to me when they are of importance (again exactly like the brain works)

Sorry for the rant.

</comment><comment><USER4> Good article.

The point about the term becoming muddled and meaningless is pretty spot on. When I first started hearing this term being used all over the place (heck, Toronto's already had a couple mini-conferences laced with this buzzword), I assumed we were talking about systems with "real time" data flows like Pachube.

Now the term seems to have boiled down to "I taped my F5 key down".

</comment><comment><USER5> I am yet to find any use for the Real Time Web in whatever (twitter,email,facebook,rss feeds) format. As a consumer none of these actually enhance either my productivity or knowledge in anyway, they are merely there for entertainment.

Surprisingly, the only exception to that is probably FreeNode IRC , certain channels at least.

Yes, there are certain bloggers i want to read, certain discussions on HN that i want to participate in but it takes time for me to assimilate and understand what is going on, the RTW doesn't help me there.

<comment><USER6> I find twitter search useful. For example, when I was shopping for a newly released netbook, I searched the keyword on twitter for a few days, to see what people say about it and what new reviews are being released. After a few days, I was able to detect the "mood", in other words, how people feel about the product. That is very hard to achieve with just reading a professional review.

More generally, if I want to know what _now_ is happening about something, twitter can usually deliver that.

<comment><USER5> "I searched the keyword on twitter for a few days"

There, you have used Twitter in the fashion of the "traditional" web, you just went to a RTW source thats all.

My point is i generally don't have any use for what "now" is happening, anything that is of importance generally has a longer time span and relevance to me and i don't "need" to know it straight away.

</comment></comment></comment><comment><USER7> The best use I've found of the "real-time web" is for tracking live sporting events that I can't attend or stream over the Internet.

For example, I play fantasy football and I noticed during Sunday afternoon that Kevin Smith (Lions' RB) suddenly stopped scoring me points. Did he get injured? I don't have cable & Google's "recent results" showed nothing... so I performed a Twitter search for his name and my worst fear was confirmed by dozens of Lions fans on Twitter: he was out with an injury.

The result of my search wasn't desired, but the "real-time web" was the only place to get the info.

</comment><comment><USER8> I think the real value of the real-time web will show when the comments sections of all webpages are in real-time. This will allow users who are viewing an article on the same webpage, which may be over a decade old, to see a comment appear as it is sent. This will encourage users to comment back and forth across all webpages, no matter how old the page is, due to the real-time appearance of comments.

<comment><USER9> What are the chances that someone viewing a decade-old article will just happen to be viewing it at the exact same time as someone else is viewing it AND at the exact same time that this other person is submitting a comment on it?

<comment><USER8> A higher chance than you think, especially with search engines which offer immense amounts of historical content. I believe if there was a comment system put in place which informed visitors of how many other people were on the same page with them, this may encourage readers to chat amongst each other in real- time and bring life back to webpages which were once "ghost towns".

</comment></comment></comment><comment><USER10> Would be the same to argue that TV is destructive because it has continuous broadcast. Do not like it turn damn TV of. Regardless of how much buzz the term has, it is valuable in some cases(some are mentioned din the article) and it is up to the user to decide what value it has for him. Rather than talking about negativity, just make it optional so user can make a choice of turning it of or on.

</comment><comment><USER11> This reminds me of a project I worked on in a large enterprise years ago. All of their systems, believe it or not, were batch. Inventory, accounting, order processing - all data was entered into hold files, or worse, filled out with pencil and paper and turned into keypunch. All databases were updated in a large batch overnight. (Today, it's hard to believe anyone ever did that.)

Our project was to migrate all apps to a new real time package. They spent millions of dollars and when it was all done, the controller complained, "Who decided that we needed real time Accounts Payable? Why would we ever want to pay our bills _faster_?"

No one had ever asked that question before. No one even thought about it. We had spent $1 million on a module nobody wanted because IT decided it. Eventually he added procedures to continue to fill out all accounts payable transactions with pencil and paper and enter them into the on-line system at the end of the day. What a waste.

Same argument here. Some things you want faster. And you're willing to pay for them, one way or the other. But other things should just stay the way the are.

Some things never change: you actually have to _think_ about your apps before you implement them.

<comment><USER12> I see this quite a bit in my current job.

Question for you, how did IT sell this to the business folks (or the buyer)? Was this under the auspices of enterprise agility?

<comment><USER11> _Was this under the auspices of enterprise agility?_

Exactly. If a customer called in an order at 6:30 a.m., it didn't even get to the data base for 18 hours. So there was no same day shipping and if it had to be scheduled, the schedulers weren't even aware of it until the next day. Real competitive disadvantage. Worth spending millions to solve.

Real time Accounts Receivables paid for itself by reducing Days Sales Outstanding by one day. But real time Accounts Payable? Made no sense.

The IT solution was a blanket decision made multiple levels (and cities) away from the people who actually did the work. Go figure.

<comment><USER12> Man I see this so much at my job. Its amazing that architects don't catch things like this. Was there any requirements written up or charters that justified moving accounts payable to real-time?

Its pretty inane, as you point out, how companies blindly apply strategies. Alot of times this is caused by simply cutting corners. If they would have had a body write up requirements (even high-level) for each department the would have caught this.

Were there any problems with the actual implementation? If there are these kind of problems at the architecture level, I can only imagine the issues that came up actually initiating and executing the program.

</comment></comment></comment></comment><comment><USER13> Back in January, a guy at the coworking space I was at that day announced that a plane had crashed into the Hudson. We were like - what? He said his girlfriend worked in a building overlooking the Hudson and saw it - <USER2> instant messaged him via AIM - and we tried to verify it. It seemed so out there. A plane in the Hudson?!

Twitter didn't have any info on Flight 1549 for a minute or so. In fact, the real time Summize search engine backend - seemed to be lagging in its indexing that morning. CNN and the other news networks were still reporting the same political/celebrity news of the moment.

Personal word of mouth just barely beats Twitter for real-time* information but it's very close. It's true crowd-sourcing (though questionable why people will tweet they are in an earthquake while it's happening - and not be safer).

* - My hardware/software RT engineer friends scoff at the mis-use of the RT term.

<comment><USER14> What is the value to knowing this information as soon as possible?

<comment><USER13> Excellent question. I can't think of a good answer. I originally thought it was about ego (e.g. knowing about something quicker than the general public). However, I think, personally, it's more about being able to observe an event from the distance of a first-person third-party (#lessconf is a great example) as the event unfolds (in, yes, "real-time") The thirst to acquire knowledge/news without the cost of having to actually have a personal or even virtual relationship with those sharing.

</comment></comment></comment><comment><USER6> >>> If you're a consumer of information (and we all are), turn off the live notifications, unless you need the information for your work. <<<

This looks like a common knowledge to fight distraction, but anyway: I currently experiment with email notification, and I start to reconsider using it again. The point is, that the small blurb doesn't actually distract me that much, and I immediately see that nothing important is coming, and as a result, I doesn't have an urge to check if some important email didn't come. And if something important came, I just know that immediately.

</comment><comment><USER15> So what is the value of the real time web?

This article seems to say it's about immediacy, about finding out things faster than you would have before.

I've also heard that the real time web acts as a filter for news, so you can use the people you follow on twitter or your facebook to find out what information is important.

I know a lot of people on here are working on real time apps...what do you think that value is to the consumer?

<comment><USER8> The newer information is, the more valuable it tends to be to the consumer. People prefer to know what's going on sooner than later. Just look at old newspapers, nobody buys them except for historians and newspaper collectors.

</comment></comment><comment><USER16> The term is nebulous, but I don't see the value as questionable. For example, google "new ubuntu release."

The result isn't even close to what you want--the real time web will be a good thing.</comment>


GraphHopper Routing Engine 0.13 Released - <AUTHOR> https://www.graphhopper.com/blog/2019/09/18/graphhopper-routing-engine-0-13-released/ <comment><AUTHOR> Let me know if you have questions regarding this specific release or more general.</comment>


Pentaquine (2013) - <AUTHOR> https://github.com/rvantonder/pentaquine

<comment><USER2> This is cooler than I thought at first, as I thought it was a relay. The diagram at the outset really helped show what makes it special.

And there's a link to the quine-relay; did you know the QR is up to _100_ languages?!

</comment><comment><USER3> but.. why?

<comment><USER4> Art does not require justification.</comment></comment>


How America can end its war on drugs - <AUTHOR> http://www.vox.com/2016/4/25/11445454/end-war-on-drugs <comment><USER2> America can do lots of things. Doesn't mean it will. The prison-industrial complex will not allow falling incarceration rates to eat into its profits - too many executive bonuses depend just the opposite. And not just private prisons - there bloated police budgets and military gear that will otherwise - _gasp_ \- go to waste.

And don't get me started on the DA's who must always appear "tough on crime" to get re-elected by an ever-fearful populace that is convinced that various boogeymen are planning its demise 24/7/365.

But ultimately, it's about money. Always has been. And this country values profits above _all_ else. And if a few more thousand innocent people need to get imprisoned and have their lives destroyed - well, that's a price that we, as a society, are willing to pay.

As long as WASP-y suburban _white_ America doesn't feel the pinch. As soon as some unannounced no-knock raid by a SWAT team decked out like it's Fallujah circa '05 busts in and shoots up a bunch of 18-year-old "all-American" kids, prom queens and cheer-leaders and judges' daughters and sons and all. Then and only then will you see a real outcry.

<comment><USER3> > But ultimately, it's about money. Always has been. And this country values > profits above all else. And if a few more thousand innocent people need to > get imprisoned and have their lives destroyed - well, that's a price that > we, as a society, are willing to pay.

Money didn't create the modern incarceration state. Corrections Corporation of America had about $55 million in revenue in 1990 and less than $200,000 in profits: [http://www.referenceforbusiness.com/history2/76/Corrections-...](http://www.referenceforbusiness.com/history2/76/Corrections- Corporation-of-America.html): [http://notunlikeresearch.typepad.com/.a/6a0133f1fb8812970b01...](http://notunlikeresearch.typepad.com/.a/6a0133f1fb8812970b0168e9a56b88970c-pi). The incarceration rate had been exploding for 10-15 years before that: [https://en.wikipedia.org/wiki/United_States_incarceration_ra...](https://en.wikipedia.org/wiki/United_States_incarceration_rate#/media/File:U.S._incarceration_rates_1925_onwards.png). The rise of CCA (which was a pioneer in the field), actually coincided with an inflection point where the growth in incarceration rate started _slowing down._

The incarceration craze of the 1980's and 1990's was a response to a real spike in violent crime that started in the 1960's: [http://www.urban.org/sites/default/files/wp- content/uploads/...](http://www.urban.org/sites/default/files/wp- content/uploads/2012/01/Roman_blog1.pdf) (showing violent crime per capita increasing by more than 4x between 1963 and 1992). And it was fueled by a conservative backlash against the liberalism of the 1960's and 1970's.

We can argue about whether mass incarceration was the correct response to that increase in crime. But it's ridiculous to say it arose before of some sort of profit motive. That argument ignores the data right in front of your face.

<comment><USER4> Ever heard of the "kids for cash" program? Judges would sentence kids in exchange for money from the prison industry.

<comment><USER3> That started in 2000.

</comment></comment></comment></comment><comment><USER5> But it doesn't want to. It's too central to its overall operating ideology -- specifically, the need to have a steady supply of marginalized groups, internal and/or external (the exact definition and composition of which may change over time) to arbitrarily and vindictively punish, in order to demonstrate the state's omnipotence, and keep the rest of the population not completely terrorized, but just moderately and optimally terrorized -- pretty much all the time.

(That, and because a significant portion of the population actually still genuinely believes in the need for it. The war on drugs is a complex phenomenon, like any long-ranging civil conflict, with multiple factors behind both its inception and its continuance).

<comment><USER6> I like how "most people want it" is somehow a secondary reason to a vague theory of Orwellian mind control. People want it. Therefore it is policy. Period.

As for why they want it, and the politicians who manipulate their fears... now that, I think, is real.

<comment><USER7> Depends on what exact policies you're talking about really. Marijuana prohibition especially has been majority-unpopular for a long time, and legalization majority-popular for anywhere from 4-7 years now, depending on the polls you use.

Other drugs are definitely more controversial.

<comment><USER3> Define "long time." Among the general public, it was only 2011-12 when more people wanted marijuana legal than illegal: [http://www.people- press.org/2015/04/14/in-debate-over-legali...](http://www.people- press.org/2015/04/14/in-debate-over-legalizing-marijuana-disagreement-over- drugs-dangers/4-14-2015_01). That's a very short time in political timescale (especially in a government with representative rather than direct democracy).

The public opinion on other drugs _is not_ controversial. People broadly agree they should be illegal: [http://www.huffingtonpost.com/2014/04/17/drug- legalization-p...](http://www.huffingtonpost.com/2014/04/17/drug-legalization- poll_n_5162357.html).

There is pretty much nothing 75-85% of Americans agree on, other than that heroin, cocaine, LSD, etc, should be illegal. Well, that and that we should throw people in prison for life after three felonies: [https://books.google.com/books?id=_wcyrot2kcUC&pg=PA234&lpg=...](https://books.google.com/books?id=_wcyrot2kcUC&pg=PA234&lpg=PA234&dq=support+for+three+strikes+laws+time+cnn+1994&source=bl&ots=Fn4jlAS- Fz&sig=vCJx0crZyYT4MsNgDfE4Z5PTpeI&hl=en&sa=X&ved=0ahUKEwje_u3V36rMAhUDaz4KHfVKDo0Q6AEIPDAE#v=onepage&q=support%20for%20three%20strikes%20laws%20time%20cnn%201994&f=false)

<comment><USER8> Not agreeing or disagreeing with you, just reminding people of an important relevant point.

It's pretty well proven that a survey can be crafted to guarantee the desired outcome for whom ever paid for it.

<comment><USER3> Its a Pew survey (a generally liberal outfit), and shows a change in response to the same question over time.

</comment></comment></comment></comment></comment></comment><comment><USER9> A serious question... is there _anyone_ reading this who thinks they might become addicted to heroin or cocaine if the drugs were legalized? Is illegality the main reason you don't use hard drugs?

More to the point, is there a flaw in the reasoning that legalization would lead to a significant increase in addiction, or social dysfunction due to drug use? After all, alcohol is legal and readily available, but most alcohol users are not alcoholics.

This article offers solutions all based on the assumption that legalization and ready availability would drive up addiction to dangerous levels. I'm not at all convinced this is so. I wouldn't start shooting heroin even if it was socially acceptable and only cost as much as a coffee. Neither would most of the people I know.

<comment><USER10> No heroin addict thought they might become addicted. That is one of the main dangers of heroin specifically.

<comment><USER11> seriously? do you really believe this? the addictiveness of opiates is pretty well known. I have trouble accepting that anybody starts using heroin without knowing they might get addicted.

maybe you meant something like "nobody _intends_ to get addicted". that's a very different sentence.

<comment><USER12> Then you aren't living in reality. People all the time think "this won't happen to me." I think you have a lot to learn about the world; I mean that in a nice way.

<comment><USER11> you trolling me or what? I mean that in a nice way.

</comment></comment></comment></comment></comment><comment><USER4> Marijuana was made illegal so the government could raid movements related to war opposition (e.g: hippies) and ethnical minority rights. They wanted an excuse to raid them and they found it in marijuana usage.

Then, DEA help comes with infiltrators. Among people sent to combat drugs, there are spies that carry out a large deal of espionage.

<comment><USER13> I believe it was illegal before the 1960s. Do you have any supporting information?

[https://en.m.wikipedia.org/wiki/Legal_history_of_cannabis_in...](https://en.m.wikipedia.org/wiki/Legal_history_of_cannabis_in_the_United_States)

<comment><USER14> Agreed, although I suppose LSD regulation could fit the proposed narative; "Weed" has been a political target for far longer than hippy culture. This quote is often attributed to Harry J. Anslinger, the head of the Bureau of Narcotics as far back as the 1930s.

"There are 100,000 total marijuana smokers in the US, and most are Negroes, Hispanics, Filipinos, and entertainers. Their Satanic music, jazz, and swing, result from marijuana use. This marijuana causes white women to seek sexual relations with Negroes, entertainers, and any others."

<comment><USER15> Well! Those seem like valid reasons for marijuana prohibition. Sorry to question the status quo!

</comment></comment></comment></comment><comment><USER16> What seems funny about this is the idea that we can pick a huge, broad policy, implement it entirely as-is, and leave that be for a while. I don't think that's likely to work. How it'll actually work is gradual change at multiple levels, as we're already seeing with the trend of Marijuana legalization.

It's sometimes useful to think in terms of a total broad policy, but we also need ideas for smaller steps to take that we can actually get through various congresses. It seems like the political environment might become more amenable to broader change after considerable small-scale changes and clear changes in public opinion.

</comment><comment><USER17> War on drugs is extremely useful for all levels of administration

\- How else can you confiscate private property without charges or conviction and just share the money among yourself ?

[https://www.washingtonpost.com/news/wonk/wp/2016/04/25/how-o...](https://www.washingtonpost.com/news/wonk/wp/2016/04/25/how- oklahoma-cops-took-53000-from-a-burmese-christian-band-a-church-in-omaha-and- an-orphanage-in-thailand/)

\- How else can you run a multi-billion dollar prison industrial complex ?

\- How else can you run a surveillance state where state actively encourages to snitch on fellow citizens ?

\- How else can you create vote banks of Blacks, Latinos and other who need to feel marginalized and victims ?

</comment><comment><USER18> The third option seems clearly the best. Too bad there's little appetite for the distribution of drugs by the state. Either illegality or commercialization seems to be the American way :(.

<comment><USER17> State getting into business is end of private enterprise. It is not governments job to run business.

<comment><USER18> Um really? I'm saying there should be either a brutally regulated business or none at all. The government employees in charge of distributing the drugs should in no way be incentivized to distribute more.

Markets can only work when the agents (roughly) act in accordance with their interests. I don't want to pedal the fallacy that all drug consumers are addicts, but heavy consumers make up a very large and disproportionate portion of the alcohol (let alone tobacco) industry's sales.</comment></comment></comment>


The Playmate Indicator - <AUTHOR> http://www.marginalrevolution.com/marginalrevolution/2008/10/the-playmate-in.html

<comment><USER2> Interesting, but very questionable.

The argument seems to be rooted on evolutionary psychology: when times were tough in hunter-gatherer days, men needed women who could pitch in with work to help them survive. Plausible in general, but I'm skeptical of the exact definition used for "difficult social and economic conditions". In hunter- gatherer days, this meant droughts, blights, storms, epidemics, and other disasters that made you starve or freeze to death. In contrast, even in difficult economic times, modern middle-class American men (i.e. who could afford Playboy) probably do not have to deal with anything approaching the level of duress needed to make this survival instinct kick in.

By the way, not to be dismissive, but I think the term "cute-o-nomics" was invented for studies like this.</comment>


Open letter to the authors of the hydroxycloroquine study published in Lancet - <AUTHOR> https://zenodo.org/record/3864691 <comment><AUTHOR> Original title: An open letter to Mehra et al and The Lancet

More discussion on this topic:

\- Past HN discussion: [https://news.ycombinator.com/item?id=23322658](https://news.ycombinator.com/item?id=23322658)

\- Debates on the merits and demerits on the statistics used in the paper (and in the one published by the same group in New England Journal of Medicine) are on the stat modeling Columbia blog:

\- [https://statmodeling.stat.columbia.edu/2020/05/25/hydroxychl...](https://statmodeling.stat.columbia.edu/2020/05/25/hydroxychloroquine- update/)

\- [https://statmodeling.stat.columbia.edu/2020/05/28/an-open- le...](https://statmodeling.stat.columbia.edu/2020/05/28/an-open-letter- expressing-concerns-regarding-the-statistical-analysis-and-data-integrity-of- a-recently-published-and-publicized-paper/)

\- [https://statmodeling.stat.columbia.edu/2020/05/25/this- contr...](https://statmodeling.stat.columbia.edu/2020/05/25/this- controversial-hydroxychloroquine-paper-whats-lancet-gonna-do-about-it/)</comment>


Immersive Linear Algebra – textbook with fully interactive figures (2015) - <AUTHOR> http://immersivemath.com/ila/index.html <comment><USER2> Last year, i saw the videos by 3Blue1Brown and inspired by it went on to read some of the standard text books like linear algebra application by Strang. I had seen the Strang videos earlier but somehow did not follow it through. This time however my perspective was changed. I was approaching the subject through the lens of intuition and simplicity. Wherever i found something challenging, i waited for the next day to again re-do it (because i know that this should not be that complex to understand or the understanding is wrong). And to my surprise, again and again, the difficulty was in my rigidness in understanding. The next day , or even later during the day, when my mind was fresh again, i can reason through the concept and get the intuition behind it.

Since then i have seen the Strang videos again and again. Beginning to end. Read the book chapter by chapter and exercises by exercise. And what a delight it had been. And then i jumped upon Joe Blitzstein's probability lectures. What a blast ! Is there a list of teachers like these there, who in the pretext of teaching algebra/probability etc are in reality wiring up our thinking process in ways immaterial to subject they are teaching. Many of us don't want the material to be too casual/layman terms (which hampers self understanding as its no challenging anything within us) and not too rigid (where we cannot break through the challenge).

<comment><USER3> > the difficulty was in my rigidness in understanding

At what point did you realize this? Like, could you provide a specific example of a topic you thought was hard at first but later came back to and realized was all about the intuition?

<comment><USER4> Not the OP, but...

I was just reading Landau & Lifshitz' "Statistical Physics", and can reflect on a series of thoughts that may elaborate on how intuition plays a role in the enjoyment and understanding of complex material. I've been meaning to write it down anyway...

On page 3, the book says "A fundamental feature of this [closed system/open subsystem] approach is the fact that, because of the extreme complexity of the external interactions with the other parts of the system, during a sufficiently long time the subsystem considered will be many times in every possible state." When I first read this, I thought "non sequitur, but whatever, I'll continue..." Now, the context of this quote is that the authors are trying to explain why statistical methods work at all. And they said prior that we start with laws that apply to 'microscopic' particles and use statistics to generalize to 'macroscopic' systems.

However, the second time I read this, I kept thinking it must be backwards. We didn't understand the motion of (classical) protons before understanding the motion of macroscopic balls. So we had to have been operating under the assumption that the macroscopic laws _must_ apply to microscopic objects, and then require that the must also be reproducible macroscopically through statistical methods. That is, we require that these laws be invariant across the microscopic-to-macroscopic transition. But to do that, we have to use a framework which expresses such a transition. So, for instance, if we are reasoning about the motion of a ball, we have to translate our laws into laws over the motion of some statistical model of the ball. Say, it's center of mass. And with this concept in hand, we could write laws that apply to both the macro and micro worlds, since a 'center of mass' is a macro-micro-scale- invariant abstraction. So we partition the space of all possible laws of nature, and chose to work only in that partition which encodes things we can actually know about nature -- the partition identified by the macro-micro- scale-invariant.

So re-reading that passage, it is now not a non-sequitur for me. Now it says "because the interactions with the outside world are so complex, we could not hope to predict their influence. Thus we are justified in using random variables to model their influence, and concepts that derive from the use of random variables to ensure we have complexity-scale invariance when we formulate our laws of physics." And this is not a non-sequitur to me. It follows directly from the meaning of the word "random." _Of course_ statistical methods work when the complexity of a system is indistinguishable from randomness.

\--

And this whole line of thought generalizes (albeit informally.) For instance, the meaning of words is an invariant across a long thread of contextual translations, and these invariants are used the same way: to partition the space of all possible meanings in such a way that one partition contains all of the 'knowledge' imbued by that word, and thus you can navigate a narrower space of meaning to find the intended and/or correct one. Gives me a certain brand of appreciation for good poetry.

Or -- my girlfriend -- who recently told me that she loved algebra but couldn't understand trigonometry. I tried telling her that the algebraic transformations were invariant-preserving operations selected because they conformed to known laws about 'functions' like addition and multiplication which have commutativity and identity laws, and that trigonometry was no different: different functions, but all of the algebraic transformations you needed were selected from the laws of trigonometry with the purpose of maintaining the exact same invariants. (Not that she cared much, to be honest...)

And on and on... I could probably talk for days about all the different ways every subject can be reduced to transformations and invariants and how they are used to solve problems.

<comment><USER5> > I could probably talk for days about all the different ways every subject > can be reduced to transformations and invariants and how they are used to > solve problems.

I find myself partial to this type of world view too. I believe it is part of the appeal of functional programming, at the basest level, to shape the programming model into transformations (functions) and invariants (state).

</comment></comment></comment></comment><comment><USER6> If you're interested in more great animations for a visual understanding of linear algebra, I can't recommend 3Blue1Brown's "Essence of Linear Algebra" series on Youtube highly enough.

[https://www.youtube.com/playlist?list=PLZHQObOWTQDPD3MizzM2x...](https://www.youtube.com/playlist?list=PLZHQObOWTQDPD3MizzM2xVFitgF8hE_ab)

<comment><USER7> These are the best linear algebra videos I've ever seen. The creator is now working on an introductory calculus series. He's already released the first few episodes to patrons.

<comment><USER8> Wasn't he hired by Khan Academy recently? It's great if that helps a wider audience to benefit from his work.

<comment><USER9> I think it's the reverse. He did all or most of their multivariable calc series, and maybe some other things for them.

And then started to do his own thing a little more.

</comment></comment></comment></comment><comment><USER10> Although the focus with this book is with the fully interactive figures, I'm more impressed that ALL of the book is available for free.

I'm constantly seeing more people coming out with books for free or just a passive donation link. This makes me immensely happy seeing as how they're leveraging the available free resources (Latex, CC-BY-SA content, free software for graphics) to make more resources available for free.

Open software is one thing, but a book is much more permanent in my opinion. A book like this will never go 'stale' or old like software does. We only need handful of good books for every topic out there at which point we can basically not buy books anymore. For many topics, I hardly have to consider buying a book since I can just use a free book offered by a professor. And watch course lectures.

What I want to say is this: Please write more for free. It doesn't matter if there is not much interest in what you are writing. It will help you too!

<comment><USER11> Well written software doesn't seem to go stale, or at least not quickly and poorly written books do.

<comment><USER10> Well, now that I think about it, the software going 'stale' depends on the domain.

You can write a networking stack in C adhering to a protocol and be done with it, while code for the new $COOL_WEB_APP might go out of mainstream use by the time you're done writing the networking stack.

I don't think most books, especially math and science ones go stale. A poorly written book is just that; a poorly written book. It's bad from the beginning

</comment></comment></comment><comment><USER12> This is very nice.

As a suggestion for improvement, consider allowing the learner to edit the formulas which represent the figures and have the figures update. Additionally editing the figures could update the formula in real time.

This sort of bi-directional instant feedback will aid the understanding and engagement of the learner better than figure manipulation alone.

<comment><USER13> Sounds like a good idea - one of the main ways I learned programming... and still wind up doing all the time is to just copy examples and hack them into shape, understanding what's necessary, what's not and how they'll respond to different parameters via experimentation.

</comment></comment><comment><USER14> One thing missing in comparison to most other textbooks is a set of problems to test the reader's understanding. The rotating and interactive figures are a very nice touch though.

Along the lines of interactivity, maybe having a scratch area like a Jupyter notebook would be a potentially great addition so that I could try problems near the area where I'm reading.

<comment> happy-go-lucky I thought the same thing. A set of problems to test the reader's understanding and a scratch area like a Jupyter notebook would improve the interactivity.

<comment><USER15> I've recently worked on [http://dspillustrations.com](http://dspillustrations.com) for a pictorial description of signal processing concepts. In the online version, it's not fully interactive, just animations. But after downloading, you can certainly change formulas and run it interactively.

Would be interested how one would manage to include a jupyter scratchpad in the online version?

<comment> happy-go-lucky Embedding Jupyter Widgets in Other Contexts than the Notebook: [http://ipywidgets.readthedocs.io/en/latest/embedding.html](http://ipywidgets.readthedocs.io/en/latest/embedding.html)

Temporary notebook service: [https://github.com/jupyter/tmpnb](https://github.com/jupyter/tmpnb)

Jupyter javascript plugin for static sites: [https://github.com/oreillymedia/thebe](https://github.com/oreillymedia/thebe)

Also, you may want to consider trinket: [https://trinket.io/](https://trinket.io/)

[http://www.hnwatcher.com/r/984396/Embed-interactive- Python-a...](http://www.hnwatcher.com/r/984396/Embed-interactive-Python- anywhere-on-the-web)

For example, this book uses trinket for interactive Python: [https://books.trinket.io/pfe/index.html](https://books.trinket.io/pfe/index.html)

I've just tried running:

        import numpy as np
        from scipy import linalg
        A = np.array([[1,2],[3,4]])
        print(linalg.det(A))

at [https://trinket.io/features/python3](https://trinket.io/features/python3) and it worked like a charm :)

<comment><USER15> Thanks for these great references! I will definitely have a look at them and see if I can use them for my purposes.

</comment></comment></comment></comment></comment><comment><USER16> So glad someone made this. I'm a "true believer" in animations and interactivity for learning math. They can make some concepts instantly intuitive that take a while to grasp symbolically.

</comment><comment><USER17> Discussed in 2015: [https://news.ycombinator.com/item?id=10183725](https://news.ycombinator.com/item?id=10183725).

<comment><USER18> I'm glad it's been reposted - writing an ana exam in 4 weeks!

</comment></comment><comment><USER19> on a tangent, I was just reading [https://medium.com/@dominikus/the-end-of- interactive-visuali...](https://medium.com/@dominikus/the-end-of-interactive- visualizations-52c585dcafcb)

in short (over simplified, my take): interactive visualizations are dead because nobody interacts with them.

wondering if this holds here as well.

Can't find the reference anymore, but there were also papers in educational sciences that interactive books usually don't increase comprehension of kids (they just play with them instead of depen their understanding).

edit: sorry didn't want to sound too critical. The work is awesome (upvote), was just thinking out loud.

<comment><USER20> Thank you for the link. I learned from it.

I am the author of a widely-used LA text, and have considered adding interactive stuff. But there is a tradeoff. For one thing, it locks you to online, and despite the claims of our IT people, my correspondents (mostly self-learners) do not want online, they want print or PDF (as do I, since the appearance that LaTeX gives me is important to me).

For another, the tech has in the recent past changed so fast that maintaining the interactives would be a significant job. I don't mind learning JS to do something good but tying myself to many hours a year responding to bug reports from people on obscure platforms, or using IE6, is not a good use of my life energy.

Finally, I had a colleague, a complex analyst, try _Visual Complex Analysis_ and he reported that students did not get it. He is very sober, very caring, very reliable. This starts to make sense of his report.

<comment><USER21> I'd be interested to know your thoughts on the Essence of Linear Algebra videos by Grant Sanderson. What role do you see material like that playing? (They are fantastic if you're not familiar) [http://www.youtube.com/playlist?list=PLZHQObOWTQDPD3MizzM2xV...](http://www.youtube.com/playlist?list=PLZHQObOWTQDPD3MizzM2xVFitgF8hE_ab)

<comment><USER20> Yes, I admire them. I have some technical quibbles, as a fellow educator, but I admire them a lot.

</comment></comment></comment></comment><comment><USER22> To me this book looks like a whole bunch of equations, with some fancy graphics sprinkled on top. And, far too many equations! Linear algebra is much more elegant (simple) than this. To pick one example, they define the inner product using the cosine of the "smallest angle between the two vectors." Sure if you want to calculate a number (an inner product in two dimensions), and you happened to know the angle in question, this might be helpful. But otherwise it completely obscures everything else about the inner product. How does an interactive graphic help you understand wtf is a cosine doing in this equation? What is a cosine anyway? Where is the graphic for that?

This just seems too backward and over-done to me. But go ahead and test it on some newbies, maybe I'm totally wrong here.

<comment><USER23> More importantly, the _definition_ of the cosine is given by projecting a unit vector onto a given directed line, and then measuring the length of the projection.

The way to find a given cosine of a given angle between two arbitrary vectors is by taking the dot product of the two vectors and then normalizing by their lengths.

Using the cosine to define the dot product is precisely backwards.

</comment></comment><comment><USER24> Try use web workers to not block UI while processing: [http://immersivemath.com/ila/ch05_gausselim/ch05.html](http://immersivemath.com/ila/ch05_gausselim/ch05.html)

</comment><comment><USER25> Does anyone know more about how the figures were developed?

I found [https://www.lth.se/fileadmin/lth/genombrottet/LUkonf2015/41_...](https://www.lth.se/fileadmin/lth/genombrottet/LUkonf2015/41_Stro__m_etal.pdf) which says "The figures were programmed using JavaScript using a graphics engine that we have developed for the interactive illustrations", but that's all the detail it gives.

<comment><USER26> Is there anything in particular that you would like to know?

</comment></comment><comment><USER27> Great content, makes it much easier to get through concepts. But as most math learning resources, it lacks examples of their practical application. "The law of cosines is a very useful formula to know" \- fine but why? Most learners can't imagine where they can apply what their teachers say, which brings it down to learn useless-for-them terms, needed just to pass exams. Some basic examples like these would make it much more reasonable to learn: [http://study.com/academy/lesson/solving-real-world- problems-...](http://study.com/academy/lesson/solving-real-world-problems- using-the-law-of-cosines.html)

</comment><comment><USER28> You might be interested by this curated list of explorable explanations [1]. It has a good section on math.

[1] [https://github.com/sp4ke/awesome- explorables](https://github.com/sp4ke/awesome-explorables)

</comment><comment><USER29> If you like this, you might be interested in /r/explorables, a subreddit filled with interactive stuff:

[https://www.reddit.com/r/explorables/](https://www.reddit.com/r/explorables/)

</comment><comment><USER30> I feel as if I'm looking at the future of textbooks. This is absolutely incredible.

</comment><comment><USER31> Mandelbrot cites his ability to "think in pictures" as fundamental to his process and insights.

He offers some interesting reflections and anecdotes on this subject in this interview describing his classes préparatoires aux grandes écoles. Apparently his teacher considered him a total wildcard case who would either flunk the exams or pass with flying colours, because of his habit of approaching everything through geometric intuition rather than symbolic manipulation.

[https://www.webofstories.com/play/benoit.mandelbrot/6](https://www.webofstories.com/play/benoit.mandelbrot/6)

</comment><comment><USER32> I'm a MSc in CS student at the university where the authors (whom I've met a few times) teach.

If you have any questions you think I'd know the answer to, ask away!

<comment><USER33> Perhaps you can let them know their work is being discussed on HN :)

<comment><USER26> A good idea! Although now we are already aware. If you have any questions you can ask us here or at firstname.lastname@example.com

</comment></comment></comment><comment><USER34> The order of the words and suffices is like in Turkish. One of my English teachers who has lived in Japan for a time (and she was a Turk) told us that it is very easy to learn Japanese because it follows the same word orders, and vica verse. On the other hand English is very hard becuese there is zero connection.

</comment><comment><USER35> Amazing resource, but is it still being updated? Last update seems to be from back in July last year.

<comment><USER26> New chapter out today! This time on linear mappings.

</comment></comment><comment><USER8> Excellent work! I've been trying to get my mother (she's a physics teacher) to learn linear algebra properly for a long time. Artin didn't work (ha), Khan Academy moved too slow/bored her, but she seems interested in this.

It's important to appreciate how useful it might be to make math "tangible". Sure, someone who can define a manifold by saying "oh, put charts on it, locally diffeo blah blah" probably has a good set of mental models that help them find analogies and even "tangibilize" (word?) new ideas. Once you learn the way abstraction works, broadly speaking, you can take the training wheels off: but lots of people never get past that stage. On one hand, I see a lot of people on HN talk about how the complicated notation of academic math/CS keep people out (and there is an understandable amount of resentment at people keeping "outsiders" out with this), and on the other hand, I sort of reflexively bristle (it's gotten lesser now) at people integrating the notion of an inner product into a vector space, because it is important to not stumble later when you find out your basic intuition for something is broken[3]. (Of course, intuition can be incrementally "patched": Terence Tao's essay[3] talks about this, from the perspective of someone who is a brilliant educator in addition to also being one of the most versatile mathematicians around.)

Maybe presentations of basic mathematics that are

\- simple

\- rigorous

\- free of half-truths

can be made accessible by using such visualizations and interactive techniques to decrease the perceived unfamiliarity of the ideas? I don't think there are many[2] treatments of mathematical topics that satisfy these criteria and yet manage to be approachable: one either skimps on a clean presentation (Khan Academy), or assumes a lot of mathematical maturity (shoutout to Aluffi!) from the reader. "Manipulable resources" might help fill this gap. It's an exciting time!

\--

In the section where they give examples of matrix inverses, to give people a sense of how important multiplication order is, they give an example of RHR'H' (using a prime for inverse, R for a rotation matrix, and H for a shear matrix). One of the most beautiful illustrations[1] in the book follows, with the four corners of a square moving independently in circles, and then the book states that

        It is quite close, but it is not at all useful.

While I understand the need to clarify the importance of multiplying matrices in the correct order, maybe a short aside on the unreasonable (practical!) effectiveness of commutators[0] would be useful?

[0]: [https://en.wikipedia.org/wiki/Commutator](https://en.wikipedia.org/wiki/Commutator)

[1]: [http://immersivemath.com/ila/ch06_matrices/ch06.html](http://immersivemath.com/ila/ch06_matrices/ch06.html) ("Example 6.12: Matrix Product Inverse au Faux")

[2]: Visual Complex Analysis is brilliant, though.

[3]: [https://terrytao.wordpress.com/career- advice/there%E2%80%99s...](https://terrytao.wordpress.com/career- advice/there%E2%80%99s-more-to-mathematics-than-rigour-and-proofs/)

<comment><USER36> You have to show her the videos from 3Blue1Brown. They're so good

</comment></comment><comment><USER37> This is fantastic, and where I have expected e-textbooks to go for years. Kudos!!!

</comment><comment><USER38> Reminded me of Explorable Explanations: [http://explorableexplanations.com](http://explorableexplanations.com)

</comment><comment><USER39> Q: How would one go about creating such animations? What's the best workflow? Found the figures were slow to load.

Great resource, though!

</comment><comment><USER40> I was just wondering recently why something like this didn't exist when trying to learn about Matrixes via Kahn Academy.

</comment><comment><USER41> This looks great! Could some of you share other nice books and video series covering core CS math basics?

</comment><comment><USER42> I really like this. This would've been handy as a student. I definitely prefer this to a textbook.

</comment><comment><USER43> Jaw dropped. This is exactly what I needed to get some progress with my shader learning :)

<comment><USER44> You might also like [https://thebookofshaders.com](https://thebookofshaders.com)

</comment></comment><comment><USER45> I wish we had resources like this when I was on the university.

</comment><comment><USER46> Wow...i so so so much wanted a book just like this... Thanks

</comment><comment><USER47> This will come in handy for my LinAlg exam :3

</comment><comment><USER48> Can anyone hack this and make a PDF book?

<comment><USER49> Doesn't that defeat the point of intractability?

<comment><USER50> Interactivity maybe, intractability is not having the property of being tractable. For an algorithm, this means that its performance can not be described in polynomials. But your point is still valid, a pdf does not support animations, thus a pdf would be useless.

<comment><USER48> I didn't ask PDF for interactivity, i asked PDF for taking notes. The theory is so solid.

</comment></comment></comment></comment><comment><USER51> Wow, this is great.

<comment><USER52> Al right, where do we get it?</comment></comment>


Where did all the Objective-C programmers go? - <AUTHOR> https://www.tiobe.com/tiobe-index/ <comment><AUTHOR> The February TIOBE Index indicates that Apple lost a 10% share in the programming language market by "bluntly replacing Objective-C by Swift". Any ideas to what languages these programmers switched?

<comment><USER2> " The other 10% was consumed by other programming languages that appeared to be compilable for multiple mobile platforms. "

What cross platform languages are people using? JavaScript?

<comment><AUTHOR> JavaScript seems logical, however, the TIOBE index for JavaScript is pretty much stable between 2% and 4% over the past decades. Shouldn't we have seen an increase in popularity of JavaScript?</comment></comment></comment>


What Craigslist's "Adult Services" Decision Means for Free Speech - <AUTHOR> http://www.eff.org/deeplinks/2010/09/craigslist-beyond-censored

<comment><USER2> There's one small piece of history that I consider very relevant in any discussion of CL and prostitution. CL did not always have an erotic services or adult services section. They initially had normal personal ads (m4w, m4m, w4m, w4w, casual encounters, friendship and missed connections IIRC), but the professionals were flooding those categories with sex for pay. Craigslist didn't create the sections to attract prostitutes, it created those categories to keep the ads out of the other sections.

</comment><comment><USER3> _No one (including Craigslist) disputes that sex trafficking is a reprehensible practice that should be vigorously opposed._

Wait, what does "sex trafficking" mean in this context? Is it just "prostitution"? Because many people disagree with the banning of prostitution.

<comment><USER4> This is a hand-wavy argument. If most people disagreed with the banning of prostitution, there'd be popular ballot measures aimed at legalizing it, like there are for cannabis.

<comment><USER5> [http://cityroom.blogs.nytimes.com/2008/03/20/poll-says- yes-t...](http://cityroom.blogs.nytimes.com/2008/03/20/poll-says-yes-to- paterson-no-to-legalized-prostitution/)

In this poll of New York voters 30% supported legalizing it. Clearly the parent is correct, the use. of "no one" in the quote is clearly not true

<comment><USER4> Of course it isn't, though, because "trafficking" involves the specific kinds of prostitution in which people are transported from one locale to another with the intent of alienating them from the local population and locking them into a lifestyle that depends on the sex trade.

</comment></comment></comment></comment><comment><USER4> All I'll say here is that it's not entirely apparent that craigslist is immune from liability because of the CDA:

[http://www.ca7.uscourts.gov/fdocs/docs.fwx?submit=rss_sho...](http://www.ca7.uscourts.gov/fdocs/docs.fwx?submit=rss_sho&shofile=07-1101_021.pdf)

That case, the one I believe most people are citing when they use the words "common carrier" in conjunction with craigslist, was about an advocacy group targeting craigslist for allowing discriminatory rental housing ads. "Go sue the people posting the ads", it said. But note also this, from the opinion:

 _Nothing in the service craigslist offers induces anyone to post any particular listing or express a preference for discrimination; for example, craigslist does not offer a lower price to people who include discriminatory statements in their postings._

This is clearly true for rental ads, where craigslist provides a forum for a huge variety of different real estate ads, most legitimate, in which it is prohibitively difficult for craigslist to isolate the offensive ads. It is not as clearly true for the "adult services" ads, where craigslist has gone out of its way to segregate the ads most likely to violate state pandering and prostitution laws.

<comment><USER6> They go "out of their way" to segregate the ads? isn't it just the users posting their ads to the corresponding section?

<comment><USER4> Users can't make up their own sections.

<comment><USER6> yes, but the section isn't "prostitution". there are legit adult services in those sections as well.

</comment></comment></comment></comment><comment><USER7> Maybe we should fire those AGs because they are not making any 'discernible' impact on sex trafficking in their respective states.

</comment><comment><USER8> 'How Censoring Craigslist Helps Pimps, Child Traffickers and Other Abusive Scumbags'

[http://www.huffingtonpost.com/danah-boyd/how-censoring- craig...](http://www.huffingtonpost.com/danah-boyd/how-censoring-craigslist- _b_706789.html)

</comment><comment><USER9> I still don't understand how this is a free speech issue. The particulars of this case aside, I'm not exactly concerned that the government may be censoring people advertising illegal services. Would it still be censoring if Craigslist had a "hit men" section, and that was taken down?

Put aside your views on the legality of prostitution for a moment, and remember that it is currently illegal.

<comment><USER10> not all "adult services" are prostitution.

</comment></comment><comment><USER11> Sometimes I wish HN had a filter I could use because the constant flow of these articles and some of the opinions that follow really enrage me. Keep voting me down though and just keep wondering why the number of women in tech are so low with these kinds of chauvinistic attitudes.

It's illegal to yell fire in a crowded movie theater. That's not stepping on free speech, it's an adjustment by society to keep things sane and fair. Same thing for asking business to stop helping the selling of women.

And it's not "many people disagree with banning prostitution" - it's most MEN want to reserve the right to trade money for instant sex, regardless of the cost to society because they don't know how to regulate their cravings.

<comment><USER12> I know a few guys who worked as escorts for female clients. The clients were usually aged late 30s onwards, some lonely, some just looking for sex. Mostly they were affluent, busy professionals. Women seem to like paying for instant sex too if the social conditions are right.

<comment><USER13> " Women seem to like paying for instant sex too if the social conditions are right."

Indeed, it's said that you don't pay the [man|woman] for the sex; you pay them to leave.</comment></comment></comment>