Tesla Model 3 teardown points to $28k in potential material and production cost - <AUTHOR> https://electrek.co/2018/05/31/tesla-model-3-teardow-material-production-cost/ <comment><USER2> _"They claim that their cost analysis resulted in materials and logistics costs of $18,000 and labor costs of $10,000 for a total cost potential cost of $28,000."_

If a factory worker costs $10,000 a month, that would be a person-month of labor per car, or 4 persons to produce a single car in a week, or 20,000 to produce the 5,000 each week that Tesla aims for.

Because of that, I doubt that $10,000 labor costs number is correct.

Reading the referenced [https://www.wiwo.de/technologie/mobilitaet/elektroauto- zerle...](https://www.wiwo.de/technologie/mobilitaet/elektroauto-zerlegt- tesla-model-3-kann-gewinn-abwerfen/22625806.html), it talks of _production_ rather than _labor_ costs, so I think my suspicion is right.

<comment><USER3> I have visited the Toyota factory in Ontario, Canada. What stood out to me was how little people was involved, literally everything was automated and the only labour people were doing was testing the cars by driving it (or even just checking the colour) when it came out or standby mechanics to maintain the machines.

I see Tesla as incorporating more labour than regular cars but not extensively as modern car plants have pretty much eliminated the need for humans.

<comment><USER4> Labor does not mean only people but the cost of assembly. Robots aren't free they need to be maintained by highly skilled and in the current market also highly paid workers and theya aren't free to run either. They have expensive consumeables and they need to undergo constant maintenance for even basic things as maintaining their zero.

<comment><USER3> Yea I included the mechanics who do maintenance in my paragraphs when I was talking about labourers, you might have to reread that part, when I was there, they largely hang out in one roofed area within and arent utilized as heavily as you expect.

I think from a layman perspective we expect mechanics to be constantly busy and fixing and maintaining but they only fix if there are issues and with a company like Toyota the realization is that they're so experienced and familiar that the maintenance costs reduce with time simply because its cheaper and much more efficient that way and because its much easier to fix the same issues.

As well, a mechanic that is fully utilized is actually a bad thing as that means you plant is constantly being shut down to fix things and not producing cars, as thats how you fix things in a TPS system.

Also car plants nowadays are wonderfully automated, the materials were being shipped around using driverless carts with sensors and music to alert people or things in their way. Its also suprisingly devoid of human noise aside from the machines clanking.

</comment></comment></comment></comment><comment><USER5> The biggest cost of any car is R&D.

So this article doesn't tell us much.

<comment><USER6> It tells you what Tesla's margins are going to be, as R&D cost per unit decreases/is amortized over more units as production scales up. Check out their free cash flow [1]. You'll see that it's always in the red before production scales up (Model S first, then the X, and now the 3).

TL;DR If production continues to scale up, the Model 3 will be wildly (relatively speaking for the auto industry) profitable (and the battery cost is possibly under $100/kw, which would be big if true).

Sidenote: Elon's enormous pay package [2] that was approved requires one final condition be satisfied; four consecutive quarters with 30-percent gross margins. If I had to bet real money, I'd say 2018Q3 is when those margins begin to be realized, his compensation delivered 2019Q4/2020Q1, and his plan to go to Mars accelerate (possibly as a direct SpaceX customer).

Sidenote #2: The Model 3's battery pack has the lowest amount of Cobalt in the industry (2.8%, known state of the art is ~8%). Panasonic (Tesla's battery production partner) is currently working to remove the need for any Cobalt whatsoever [3]. Good for margins, good for production throughput, mixed bag for conflict areas Cobalt is sourced from. Can't win 'em all.

[1] [https://i.imgur.com/HjyKxTm.png](https://i.imgur.com/HjyKxTm.png)

[2] [http://money.cnn.com/2018/03/21/investing/elon-musk-tesla- pa...](http://money.cnn.com/2018/03/21/investing/elon-musk-tesla-pay- package/index.html)

[3] [https://ca.reuters.com/article/businessNews/idCAKCN1IV14Y-OC...](https://ca.reuters.com/article/businessNews/idCAKCN1IV14Y-OCABS)

Usual disclaimer: TSLA investor

<comment><USER7> > _Check out their free cash flow [1]. You 'll see that it's always in the red > before production scales up (Model S first, then the X, and now the 3)._

That's a charitable interpretation. From your link it's nearly always _significantly_ in the red, outside of a couple anomalous quarters 5 years ago, and the one quarter they sold a bunch of ZEV credits.

It certainly doesn't look like "it's positive, except when they're scaling up!" to me. I guess one sees what they want to see.

<comment><USER8> This is because they're always spending money to grow. They do this because they want to grow and are growing. This graph shows you they spent money to launch the Model S, then went profitable. After this they invested to launch the X, then went profitable. Then they invested to launch the 3, and now this year they aim to be profitable again. And you know what they're going to do after that? Spend money to launch the Y and Semi, then go profitable.

Can they use the profits from S/X to deliver the 3? Yeah, but not on the timelines that their customers and the market demands. People want their Model 3s today.

One sure mark of a hater is that there doesn't exist a configuration of reality that will satisfy their objections. Is Tesla spending borrowed money to accelerate their growth and deliver products sooner? They suck, they should be profitable. Are they using solely their profits to expand more slowly? They suck, because they're having trouble delivering their products on time. Great, awesome contribution.

<comment><USER7> > _This graph shows you they spent money to launch the Model S, then went > profitable._

The graph doesn't "show" anything. You are interpreting it in a specific (favourable) way. I don't agree. Also, free cash flow positive is not "profit".

> _One sure mark of a hater is that there doesn 't exist a configuration of > reality that will satisfy their objections._

Oh, there it is. Any criticism means you're a hater.

I'm looking at the numbers. That's reality. You, on the other hand, are operating on future assumptions that may or may not come to pass. "Becoming profitable" isn't a given, just because Elon said so. As of right now, they are losing money at an accelerating rate. I guess we'll see.

And by the way, I'm not hater. I can see Tesla being the next Mazda, who make some of the most popular cars in my area. Great cars, great company. Do you know what its market cap is? $8BB. At Tesla's current market cap they need to build millions and millions of cars at substantial profit. You can believe that they'll achieve that and an investment today still wouldn't be worth it. Does that surprise you?

<comment><USER8> What you're missing is that Tesla does not want to be a Mazda, nor a Ford, nor even a Toyota. They want to be an industrial behemoth that powers every part of the carbon-free economy. They want to be a GM, GE, ConEd, Exxon and Uber rolled into one. This is not some bizzare internet conspiracy, this has been stated in plain English multiple times and has been voted on by their board.

Now, you might think that's too risky, too ambitious, or they'll never be able to execute etc. Whatever. But you can't judge them based on your own made-up ideas and standards.

<comment><USER9> He already pretty clearly said what he thought. _I 'm looking at the numbers. That's reality. You, on the other hand, are operating on future assumptions that may or may not come to pass_

Meanwhile your counterpoint is a very vivid fantasy of what Tesla wants to be beyond a car company, which is something it's not doing particularly well. You're engaging in just the kind of fantasy "Future assumptions" in question, and really just buying into empty PR and marketing. The evidence suggests that Tesla is a car company, and struggling to be _just_ that. It's an act of intense mental gymnastics to say that no, they're not just a car company, they're a whole economic sector that started as a car company... before they've even pulled off step 1. Maybe they will be, but the odds are not in their favor, and it's going to be a moot point if they can't even turn a profit on their cars.

Arguing from an imagined future should be the job of marcom, not you. It's not a failure of imagination or a lack of faith for rational people to look at what is, not a vision of what may or may not ever be.

</comment></comment></comment></comment></comment></comment></comment><comment><USER10> And it's only selling for $35k? I thought the rule-of-thumb was that you charge 3x the "bag of parts" for a product you make, sell, and service. Apple certainly got this memo... Elon is leaving a lot of money on the table.

<comment><USER11> Thats for smaller ticket items. Boeing isn't 3x'ing the cost of a plane, and neither are car manufacturers. Toyota makes an average of $2800/car, and GM makes only $654/car [0].

Porche makes $17k/car... but that's on an average price of $100k.. so only 17%[1].

0\. [https://www.detroitnews.com/story/business/autos/2015/02/22/...](https://www.detroitnews.com/story/business/autos/2015/02/22/toyota- per-car-profits-beat-ford-gm-chrysler/23852189/)

1\. [https://www.autoblog.com/2017/03/21/porsche-17250-profit- per...](https://www.autoblog.com/2017/03/21/porsche-17250-profit-per-car/)

<comment><USER12> But the parent said "bag of parts" which implies only the cost of materials, not the full per-car cost of production, and I can't tell if that also includes things like R&D, marketing, insurance, etc.

</comment></comment></comment><comment><USER13> It's not clear from the article if this cost figure includes software engineering cost which would be significant in Tesla's case.

<comment><USER14> No, gross margin doesn't include R&D. That money's spent and gone, so is pretty much irrelevant towards future costs & profitability. Relevant from an academic perspective, but not from a business perspective.

Or at least that's the traditional view; purchasers of Model 3's now expect OTA updates so there is a little bit of R&D cost in the future but it's very minor compared to what's already been spent.

That also doesn't include self-driving R&D, but that's not included in the $35K base model so is also irrelevant.

<comment><USER7> > _purchasers of Model 3 's now expect OTA updates so there is a little bit of > R&D cost in the future but it's very minor compared to what's already been > spent._

Toyota spent almost $10 billion on R&D last year. Ford $8 billion. VW spent $15 billion.

Tesla spent $1.5 billion. What is it that makes people think that Tesla's R&D spend is so significant, and that it will diminish drastically in the future? This is an R&D intensive industry.

<comment><USER14> Toyota will spend roughly $0 in R&D on the 2017 Camry in 2018.

</comment></comment></comment></comment><comment><USER15> The cost of the car for manufacturer might be: 60% goes into into the factory and tooling, 20% into the parts and 20% is the rest.

If parts alone cost $28k and the car is sold for $35k, there is no profit in the Model 3 even if the car is successful.

What I really want to know is how much Tesla pays for product recall insurance per car.

<comment><USER16> The one they tore down has a price of at least $49,000. They haven't started producing the $35,000 version yet.</comment></comment>


Beware, Humans. The Era of Automation Software Has Begun  - <AUTHOR> http://bits.blogs.nytimes.com/2009/09/28/beware-humans-the-era-of-automation-software-has-begun/?ref=technology <comment><USER2> Some of my favorite startups these days are LaaS (L for Labor) companies like Crowdflower.</comment>


Electric Unicycle (not Trevor Blackwell's version) - <AUTHOR> http://hacknmod.com/hack/enicycle-a-self-balancing-motoized-unicycle/

<comment><USER2> Trevor Blackwell made the unicycle you attribute to Paul.

<comment><USER3> For anyone interested:

<http://www.tlb.org/eunicycle.html></comment></comment>


Quo Vadis, Cons? - <AUTHOR> http://axisofeval.blogspot.com/2010/06/quo-vadis-cons.html <comment><USER2> The article has potential, but I feel that it is too short for someone who is at best incidentally familiar with the material. If its purpose was to give the reader some threads to explore, it was fine, but each of them could have a decent section explaining the basic idea.</comment>


The war against today's dangerously dull playgrounds - <AUTHOR> http://theguardian.com/artanddesign/2019/oct/31/were-cosseting-our-kids-the-war-against-todays-dangerously-dull-playgrounds-wellcome <comment><USER2> I remember reading something somewhere about the real issue with risk and playgrounds... that modern playgrounds often hide risk, whereas older playgrounds it would be more obvious. The idea is that there were clearly places (high up, requiring climbing skill) in the old playgrounds that kids would slowly work their way up to conquering. Because the risk was obvious, kids would approach it with caution and build up skills to get there. In contrast, a lot of injuries occur when 'safe' playgrounds have kids try to do things not designed for, but because of the way they are made don't appear to be dangerous bus actually are. Giving kids the ability to assess risk accurately, and develop the skill to take that risk, is the important part.

<comment><USER3> The rules we have here in Norway, which is a variation of a EU thing IIRC, allow kids to get hurt, but not permanently. There are a lot of dangers which are non-obvious, especially to a kid. Crevices where the rope for tightening the hood can get stuck, potentially strangling them. Stairs where a kid can get their head through but not their body. Swings where they can lose their fingers thanks to the chain mounts or similar. Lots of similar things.

I have a friend who design playgrounds, and he operates on the principle that there's two kinds of safety. It's the objective safety I mention above, and there's the subjective safety which you mention. Kids should have objectively safe playgrounds, but they should be allowed to challenge their subjective safety feeling.

The objective safety has mostly to do with the design and maintenance of the equipment. The subjective safety is more due to the design of the playground itself and the elements in it.

One example is a climbing wall. With the right layout, sufficient impact sand or rubber on the ground around it as well as proper maintenance, it can be objectively very safe but still allow kids to feel they push their boundaries.

<comment><USER4> Your comment made me think of a great comment on the topic I had read here a few months ago. After some digging around, I found it, and it turns out to be a post of yours, too! :)

[https://news.ycombinator.com/item?id=19924858](https://news.ycombinator.com/item?id=19924858)

Very cool, thanks, keep posting!

<comment><USER5> The slide in your linked article resulting in a lawsuit was 12 feet tall. I recently played at a kids (something like 4-10) park that has a climbing feature that one can get to the top of that is a bit taller than that. It was fun but I was thinking the whole time, this could never go over in the USA.

[https://goo.gl/maps/bF6bSSQ93SbUuHs96](https://goo.gl/maps/bF6bSSQ93SbUuHs96)

<comment><USER6> An inflatable park company came to our town for a bit with a bunch of rides, one of which was a super high slide. I didn't understand why they were making us get into burlap sacks before going down, but I understood later - the speed near the bottom was high enough that I'm pretty sure I would've walked away with major burns if I'd touched the slide. My wife ended up with a mystery burn she noticed at the end of the day that I suspect came from this.

</comment></comment></comment></comment></comment><comment><USER7> I let my toddler do absolutely whatever he wanted on local playgrounds and let him have some nasty falls. Unsurprisingly he learned very quickly what his comfort zone is and when he has to be extra careful.

My philosophy is that it's not my job to protect him from harm. It's my job to protect him from irreparable harm. The point being that he has to learn how to cope with being hurt and getting hurt is the only way to learn where the line is.

<comment><USER8> I have a 14 month old, and I find it fascinating to watch him play. He's super active, starting to stand, walks very fast when I hold his hand, but not yet confident on his own.

He loves the outdoors. He will literally yell and cry at us to take him out for walks and/or to the park. Loves when I take him on the playground.

When we climb up, he loves to crawl through the tunnel and finds it hilarious when I chase him to stop him from getting away from me. He will definitely try to go down the slide by himself, or crawl out of the playground to a 5 foot drop. It's as if he has no concept of the dangers.

Meanwhile, I generally let him do what he wants elsewhere, like climbing stairs, crawling into cupboards, etc. He picked up a pretty gnarly bruise on his chin when we went swimming and he fell in the change room.

To his credit, nothing seems to deter him. He'll cry for maybe 30 seconds, often less, take a quick hug from me, and then jump right back to whatever he was doing.

I can't wait until he's actually walking because then I can expose him to some riskier stuff, which he'll enjoy. Winter's almost here, so I expect him to be walking when we start enjoying the playground more often again.

<comment> semi-extrinsic Don't stop going to the playground in winter ;)

If you have snow, get him a snow sled for toddlers. Stiga makes a really nice one called the Baby Cruiser. It has a large back rest, cushion and a seat belt. And the design makes sure the speed remains low enough, unless you take it out on icy conditions (which you shouldn't).

As a bonus, in spring you can put it on top of a skateboard, run the seat belt around both the sled and skateboard, and presto you can "sled" in summer. My kids used to love that.

[https://www.clasohlson.com/uk/Stiga-Cruiser-Baby- Sledge/p/Pr...](https://www.clasohlson.com/uk/Stiga-Cruiser-Baby- Sledge/p/Pr349235000)

<comment><USER9> I'm jealous of how well my child, almost three, can walk/run and cope with the snow and ice. He's almost as stable running on snow/ice as he is on solid ground. Unlike myself.

Sledges are awesome though, and also highly recommended. I take him to daycare on one when the ice/snow is suitable for it. If only the city wouldn't grit the pavements it'd be easier!

<comment> semi-extrinsic Kids have two big advantages on slippery conditions, both coming from the square-cube-law: they have a lot more traction relative to the torque they can put into a stride, and their moment of inertia tensor is less ill-conditioned.

</comment></comment></comment></comment></comment><comment><USER10> One of the unexpectedly adventurous organisations when it comes to playgrounds in the uk is the National Trust.

When I was a kid, a visit to an NT property was being dragged around some posh house where you couldn't touch anything.

Somewhere around 15-20 years ago I think they realised their clientele was getting older and older and ever since they've been on a bit of a mission to make more of their properties kid/family friendly. They now have some of the best play areas we know of, most of them in woodland, with the equipment etc made of wood, often taken from the woodland, or built into the landscape. We took a small group to one today, and they would have spent hours playing there if we'd had the time, much longer than they will play at some of the more structured "modern" play areas near here.

<comment><USER11> Do you have suggestions of any particularly good ones?

<comment><USER10> Near us, Tyntesfield is great. There is an obstacle course type one down by one of the cafes, then there are three on a trail up in the woods. Some are more structured than others.

We've taken to using NT sites as breaks on long journeys. At a minimum they will have a cafe, and most will have something to give us and the kids a nice break from the car. Its definitely a nicer way to stretch your legs than a motorway sercvice station. The app is pretty useful for this.

They can be pricey as individual visits, but if you go to more than a couple a year, a family membership pays for self pretty quickly.

</comment></comment></comment><comment><USER12> When each of my kids turned 5 I started letting them go around the block with another kid, 2 kids minimum. My neighbors started texting and calling me as if my kid was in danger. They couldn't understand that I let my kid out of my sight. The best playtime is unsupervised. Being allowed to be out of sight and making your own decisions builds confidence. We learn from mistakes, we learn less when we are prevented from making mistakes.

<comment><USER13> I want to do that but Nextdoor posts about attempted kidnappings give me pause.

<comment><USER14> [http://www.disastercenter.com/crime/uscrime.htm](http://www.disastercenter.com/crime/uscrime.htm) scroll down for crime / 100,000 people.

Nextdoor tends to attract people who worry about anything and everything, and who report anyone they don't recognize (or just don't like) as being suspicious.

</comment></comment></comment><comment><USER15> I find the playgrounds in my city (Tampa, FL) to be excellent. This article is completely wrong about the parks here.

I have 5 young grandchildren and a 20 month old son, so lots of observation time. The grounds are wildly loved by the kids there. They have rubber surfaces that dramatically reduce broken bones, but do _not_ prevent pain. I love that they still get scrapes, bruises.

The sets are large, complex, and _fun_. My kids will spend as many hours as we let them.

<comment><USER16> How old are the kids you are talking about? 20-month-olds are happy with literally any playground, especially if there are a few other kids. They are still learning the very basics of climbing, running, sliding, swinging, ...

Most playgrounds are okay for 0–8 year-olds. It's older kids, especially teenagers, who get most bored on de-risked modern playgrounds, and either give up on them or start looking around for (often quite stupid) ways to make them riskier, e.g. a group of 6 kids climbing onto a swing intended for 1 kid (thereby breaking it), riding their skateboards down the slide (and almost running over the toddlers at the bottom), climbing up onto the roofs of buildings that weren't intended for climbing, throwing rocks at each-other, ...

The playground near my house was re-done a few years ago, and the number of kids older than 10 has dropped dramatically. All of the toddlers are plenty happy with the new one, but it's a net loss for the city because there are many good playgrounds for kids under 8, and very few for older kids.

Aside: those rubber surfaces are very uncomfortable on bare feet any time the temperature is above 80°F. And often playground wood chips are full of extremely sharp corners (My adult friend stepped on a wood chip which punctured both his shoe and his foot). Sand, dirt, grass, and even concrete are all much more pleasant.

<comment><USER17> I was a kid when we still had dangerous steel playgrounds and by the time I was in 5th grade, it wasn't cool to play on the playground.

Middle schools never had them as far as I know. So around 10 seems to have always been the max age for playground equipment.

<comment><USER18> I used my local playground until I was 16. Now, nearly 30 years later I still go to the playground to play, but it's a climbing gym. People don't magically stop playing soccer, or baseball, or video games when they pass age 10, I don't know why we assume as much about playgrounds. A well built playground offers challenging terrain for kids of all ages.

<comment><USER19> omg if I saw a 46 year old climbing around a playground by himself, I would... keep my child close to be sure.

Is that the right reaction to have? I think it probably is.

<comment><USER18> I think you're insane and I'm glad I'm not your kid.

<comment><USER17> In our current society it's certainly not normal for an adult to be climbing around on a playground alone. And it's not insane for a parent to approach such a situation with caution.

And regardless of whether you agree with the OPs's reaction, that's the reaction that the vast majority of parents are going to have.

<comment><USER20> Oops, guess some parents are going to have a bad time. Their problem, not mine. Parks are for everyone to enjoy. Bigotry in action, and a slew of apologists. Sad.

<comment><USER17> >Oops, guess some parents are going to have a bad time.

No it's the 46 year old alone on the monkey bars who's going to have a bad time. At the very minimum police will run them off. There are plenty of cities that have ordinances banning unaccompanied adults from playgrounds, and a 46 year old who insists on doing this is just going to ensure their local municipality passes such an ordinance.

I personally don't care if an adult wants to play on a playground, but making a kids only zone is hardly bigotry in action.

</comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER21> No mention of the Harbourfront Adventure Playground in Toronto, in the 70's and 80's, a very famous example of an unsafe play environment:

[https://www.blogto.com/city/2017/09/adventure-playground- tor...](https://www.blogto.com/city/2017/09/adventure-playground-toronto- history/)

<comment><USER22> There is an adventure playground in Berkeley that my kids adored when I used to live in a nearby city. I'm not sure how it's avoided a similar fate to the Toronto example you refer to, but it's a wonderful place. Terrifying to watch as a parent no doubt, but empowering for the kids.

</comment></comment><comment><USER23> In my experience the best playgrounds are not playgrounds at all.

As a kid my playground was the mountains, the beach, playing with sand,dirt, climbing trees, making cardboard's or bricks' or wood houses. Hearing and telling stories around the campfire...

I was terrified when I went back to visit a school I was when I was 4-6 years old. Instead of just one big piece of land for kids to play they had divided it with fences in something like 20 small spaces so they could control kids easier.

It was a prison. I believe this has to affect the kids development somehow.

I also feel bad for a playground like the one in the image: [https://i.guim.co.uk/img/media/1094dd57d6a80c1ae1fb131937de5...](https://i.guim.co.uk/img/media/1094dd57d6a80c1ae1fb131937de58d4ab6b6fd8/0_0_5374_3575/master/5374.jpg?width=1920&quality=85&auto=format&fit=max&s=685b226959c0ecd95cdd92c8470d0d61)

Because kids have imagination, they don't need a ship. If they have boxes they have a ship, or a space center or everything they could imagine.

This is like a father buying a toy for his children and then only he playing it, not letting his children play.

A adult designer takes the best part: imagining, and then doesn't let the kids imagine anything else as you can not move or modify anything in the ship like you can do with boxes or wooden logs.

That is making a tremendous disservice to children.

<comment><USER24> > I also feel bad for a playground like the one in the image: > [https://i.guim.co.uk/img/media/1094dd57d6a80c1ae1fb131937de5...](https://i.guim.co.uk/img/media/1094dd57d6a80c1ae1fb131937de5..).

Disagree 100%.

My kids absolutely LOVE that playground (assuming it's the one in Hyde Park, London). It's nowhere near where we live so we've gone there maybe 5-10 times tops.

But they love it, and beg to go if we're nearby.

The main problem I have with it is that unlike the picture it can get insanely crowded, sometimes with a queue waiting to go in, managed by park officials.

Not sure why you think a fun ship discourages creativity. My kids regularly do creative play and role-playing anywhere, at home or out and about.

But it's also just really cool and tons of fun to climb around on a giant (to them) wooden ship.

</comment></comment><comment><USER25> My mother wrote her master thesis on the correlation between risk in early years children and success later in life (a long time ago now) It turns out if you allow children to take (reasonable) risks, then they go on to be more successful in their careers. This is now a relatively well known correlation. I loved doing 'dangerous' stuff as a child and this utopian playground makes me sad that most of today's kids are shielded from it.

<comment><USER26> > It turns out if you allow children to take (reasonable) risks, then they go > on to be more successful in their careers.

How did she control the study well enough to assert that there's a causal relation? Or was it just a correlation?

</comment></comment><comment><USER27> Problem isn't so much about risk adverse cities, it's more about litigious parents. If the city does anything That is considered risky, they open themselves up to big lawsuits if the children do get hurt.

</comment><comment><USER28> All these old pictures showing kids having fun in environments we consider harmful, always depict kids older than those we typically let play in playgrounds.

From the age of ~3 kids start to learn their motor skills to climb, grab, jump, do all sort of stuff.

Kids of the age of these pictures, you let them play wherever that's not a death trap, they'll basically be fine.

<comment><USER29> Stay out of the abandoned mineshaft, kids!

</comment></comment><comment><USER30> They do have softer ground and rounder corners but the playgrounds today are way cooler than I was a kid. The one near me has climbing walls and a zip line. It's crazy.

</comment><comment><USER31> Calling this a war is the reason the saying "pick your battles" exists. Anyone who is a parent knows that kids always find ways to hurt themselves, there is no shortage of opportunities. Might as well make playgrounds safe, kids don't care as long as they have fun.

</comment><comment><USER32> Kids, uh, find a way.

I remember when my school replaced the entirely wooden and very interesting play structure from the 70s with one of those new colorful, tubular metal ones. It sure looked safer. The 15 foot spire we took turns leaking off was gone. The tire swing that took out many a passing kid was gone. The piece of 5ft diameter concrete drain sewer pipe I busted my head on was gone. But that didn't stop one kid from nearly scalping himself on the new equipment, requiring 28 Staples. Nor did it prevent broken legs from falls, or many other injuries. But it sure looked safer and I guess we didn't get as many splinters. But kids always find a way to get hurt.

<comment><USER33> My daughter just tried to sit down the other day.

Missed the chair and ended up cracking her head on the bookshelf behind. Had to go to hospital to get glued back together.

</comment></comment><comment><USER34> Sure, some playgrounds may be mind-numbingly dull, but those are a well- intentioned response to older playgrounds that posed serious physical dangers. You can argue that getting a little bit scraped up once in a while isn't bad for children; it may teach them lessons about how to avoid such future mistakes - but plenty of children have sustained more serious injuries on playgrounds that allowed them to climb much higher than they could on, say, a tree in nature (speaking from my life experience). I think the article conflates the issue of modern over parenting with safer playground design - which if done right, can only be a good thing.

<comment><USER35> I've fallen from trees higher than any playground. Only serious injury I ever had was on (and because of) AstroTurf.

<comment><USER36> Ditto, I grew up in the woods so climbing on trees was an everyday activity for me, more frequent than playing on playgrounds. I used to climb trees as far as the tree would support, then climb it further until it collapsed. I fell out of more trees doing that than I can count.

Thankfully, helicopter parents cannot hope to regulate trees.

</comment></comment></comment><comment><USER37> Unfortunately this article is pointless. It's just unsupported assertions. The only part of the article which approaches something worth writing about:

> As for the increased dangers, she says Play England has a rigorous > assessment system that measures the risk against benefit.

I'd be really curious to know how they quantify risk for different designs and how they calculate "benefit" in way that can be measured against it. Unfortunately, the author decided to fill an article with unsupported assertions instead.

<comment><USER38> The pictures though. In the background of the top one, behind the hand of the kid who's standing on the tire, there appears to be a the ribcage of an enormous animal sticking out of the ground.

<comment><USER39> That's a corrugated steel panel.

</comment></comment></comment><comment><USER40> I am surprised not to see jonathan haidt mentioned- his views on this subject align with the authors, and he brings an interesting perspective to the table.

</comment><comment><USER41> I really liked this[1] talk at Google comparing how kids are raised in Germany vs the US. She touches on the topic of playgrounds starting at 11:30, but the whole talk is really worth watching in my opinion.

[1] [https://www.youtube.com/watch?v=L7-k6nK1VUw](https://www.youtube.com/watch?v=L7-k6nK1VUw)

</comment><comment><USER42> The bay area city I live in is going through the initial process ["community input"] of replacing//updating some playground equipment at the park nearest to where I live. The proposed updated equipment is supposed to be "all inclusive" for kids in terms of age and ability. About a week ago there was an opportunity for neighbors to "choice rank" the top three across each the different types of equipment by example pictures: top three slides, top three climbers, spinners, noise makers, swings.

To me the current equipment seems fine but the city is claiming "end of life" and I have no objective reason to doubt.

What I did notice is that the current equipment is made of materials such as wood and rope with some plastic. The new equipment will be primarily plastic and metal. I wonder if splinters have become the Great Evil for Junior since I had cause to attend a swing set.

</comment><comment><USER43> Growing up, my elementary school had an amazing wooden structure that had been built in years past. After I left, it was torn down and replaced by a prefab thing with much less character and probably less fun. The reason given was liability insurance was more possible with the later generic playground.

<comment><USER44> This has been on my mind a lot lately. It's not just risk changes, it's also variety changes which are also important.

Near us there's nice, challenging playgrounds, but their designs have become homogeneous. The older playgrounds had more unique features to each, with custom molded fiberglass.

I don't mind some playgrounds drifting to other materials, but the wood ones also have something to offer. I worry they're slowly being replaced by the same sorts of hdpe and brightly painted metal structures that are everywhere else. They're nice but all start to seem the same after awhile.

It's sort of like if houses all got torn down after 30 years and were all replaced with variants of the same template, rather than preserving older structures or encouraging innovative architecture.

Kids have as much to learn from variety as they do risk.

</comment></comment><comment><USER45> I feel like I live somewhat close to a really risky park: [https://www.eastidahonews.com/2018/06/new-pirate-island- play...](https://www.eastidahonews.com/2018/06/new-pirate-island-playground- officially-open-rigby/)

It is wonderful.

 _sigh_ I have to wonder just how long it'll last. I did see a section on the concrete rock structure that looks like ther was supposed to bw some sort of rope bridge. I guess that got removed.

<comment><USER46> I took a look at your link and I don't understand why you feel it's "really risky". To me (a German), it seems like any other playground with quite common elements. Sure, the climbing web (if that's what it's called) is high, but this is a structure where kids will not even get that high if they are not skilled.

All the images and videos just looked so American to me. A guy pulling kids in wagons with his motor vehicle, where I'm just asking myself: Why? And of course, almost all the adults and a fair amount of the kids are overweight …

I'm not trying to bash America, but this did confirm quite some stereotypes of mine.

</comment></comment><comment><USER47> When I was a kid (circa the mid-1980s), there was a real Korean war F-86 Sabre in the middle of a sandpit and a steel labyrinth maze that was shaped like a skyscraper with about 8 levels (tall: 13 ft/4 m, wide: 10 ft/3 m, deep: 3 ft/ 1 m) to crawl through at the De Anza playground in San Jose. Looking at Google Maps, it now contains depressing McDonald's-looking, clown-colored boring stuff no kid is really interested in.

</comment><comment><USER48> Kids like a challenge, they are constantly testing their boundaries. It's part of learning risk and what they are capable of. That's very true modern playground hiding risk, in my childhood playground you saw the climbing wall as the biggest challenge you tried it once you were ready and had done a few trials runs on smaller ones.

<comment><USER49> Oddly was never much the case for me. I ended up never experiencing some of the "harder" or more "dangerous" parts of the playground because I just wasn't interested if it seemed too risky. I'd see other kids climbing to a dangerous spot and think they were dumb.

</comment></comment><comment><USER50> I've seen some pretty cool playgrounds in the last year where I live, personally

</comment><comment><USER51> Related discussion from a few months ago for those interested: [https://news.ycombinator.com/item?id=19900498](https://news.ycombinator.com/item?id=19900498)

</comment><comment><USER52> What a bunch of aging-boomer kid's-these-days hyperventilation, bereft of data and full of tut-tutting.

Playgrounds in 2019 are full of playful risk. And if you want something more dangerous, there's everywhere else to choose from.</comment>


Decorating ActiveRecord Accessor Methods - <AUTHOR> http://onehub.com/past/2009/6/25/decorating_activerecord_accessor_methods/

<comment><USER2> Doing it this complex way would never have occurred to me. I would simply create an accessor method in the ActiveRecord model that doesn't exist in the database to take the hash and have it set the database field as a side effect, or in a before_save filter.

<comment><USER3> Yes, I suppose that would have worked as well, and would've been more in the spirit of the first attempt at a solution, but it wouldn't have been very general, and it certainly wouldn't have worked for all models in the application (without a lot of manual intervention).

<comment><USER2> Oh, it could be made general, just add the name of the actual datetime field as a parameter of the hash. Then you could drop the method into ActiveRecord. Anyway, the second solution is okay, because it is explicit enough. However it it still builds a dependency on define_attribute_methods.</comment></comment></comment>


Lynx SD Menu Loader Version 2 - <AUTHOR> https://atarigamer.com/articles/introducing-lynx-sd-menu-loader-version-2 <comment><USER2> Interesting, I had a chance to get my hands on a Lynx a few years back but turned it down due to a lack of decent flashcart solutions. Seems things have come on a long way!

</comment><comment><USER3> I never thought I'd get my notice to update one of my flash cartridges from HN, and here we are. It's a slick piece of hardware overall.</comment>


Check out Identical Twins Otto and Ewald - <AUTHOR> http://thesameffect.com/check-out-identical-twins-otto-and-ewald/

<comment><AUTHOR> I heard about identical (monozygotic) twins Otto and Ewald from a German researcher at the 2010 International Society for Intelligence Research conference in DC. I just asked a local friend who is a behavioral genetics researcher what website he recommends as a first look at Otto and Ewald, and what they mean for the nature-versus-nurture question, and he surprised me by recommending the site for popular audiences submitted here. He says he uses the pictures from this site each time he teaches undergraduates about human genetics. Heritability matters, but specific training matters too.</comment>


A hand-wired USB and Bluetooth keyboard powered by Python - <AUTHOR> https://github.com/makerdiary/python-keyboard <comment><USER3> A lot of people are asking:

\- why python?

\- isn't is slow?

Remember that Python is a language spec, there are several implementations.

This project uses a particular implementation called CircuitPython ( [https://en.wikipedia.org/wiki/CircuitPython](https://en.wikipedia.org/wiki/CircuitPython)), a derivative project from MicroPython ( [https://fr.wikipedia.org/wiki/MicroPython](https://fr.wikipedia.org/wiki/MicroPython)), by the people at AdaFruit.

This implementation runs with a very different VM that can fit within 256k of code space and 16k of RAM.

So, while obviously you cannot expect anywhere near C level of perfs, this is way lighter than CPython.

The advantage is that you get the ease of Python to program your board, including the clean terce language, the memory management and the rich data structures. You can even have a live shell on some embeded hardwares! The whole dev process is so simple: code, copy your module, run.

Of course, some features of CPython are not available.

<comment><USER4> many people dont realize, but micropython has unix port, and it can be much slower than CPython. micropython's main advantage is size, not speed.

</comment></comment><comment><USER5> Great job! I've not seen python-based keyboard firmware before, I'm impressed that it's fast enough to run something like a keyboard.

Without detracting from the code in the post, I recommend that anyone wanting to make and program their own keyboard should take a look at QMK, a widely supported keyboard firmware project that is FOSS: [https://qmk.fm/](https://qmk.fm/)

</comment><comment><USER6> If you want to make a little macro-keyboard equivalent at a fraction of the cost, I wrote a little guide (with example code) here: [https://makeandymake.github.io/2020/05/02/seeeduino-xiao- cir...](https://makeandymake.github.io/2020/05/02/seeeduino-xiao- circuitpython-usb-hid-macro-keypad.html)

<comment><USER7> this is pretty cool!

I've wanted to hardwire a keyboard, but a full-size one seems pretty intimidating.

</comment></comment><comment><USER8> This looks cool, however can someone with some electronics know-how explain to me why the connections on most, if not all the keys are crossed? They don't look like insulated wires, though I could be wrong.

<comment><USER9> Insulated wires that look a lot like bare metal are quite common, e.g. in electromagnet coils.

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

The insulation melts away where it comes in contact with hot solder, so it's very easy to work with for hand-wiring projects.

</comment></comment><comment><USER10> This is nice, we need more such open-source, affordable keyboard designs and components; Especially for accessibility keyboards[1] as their costs are exorbitant.

[1][https://needgap.com/problems/96-one-hand-keyboard- keyboard-a...](https://needgap.com/problems/96-one-hand-keyboard-keyboard- accessibility)

</comment><comment><USER11> Haha that's amazing. What's the latency on this though? I always assumed firmware written in python would be slow for a use case like a keyboard.

<comment><AUTHOR> It is a bit slow. It takes 4 ms to scan the matrix once right now. With some optimizations, it may be faster.

<comment><USER12> Would Numpy be of use? Haven't looked at the source yet, but for a keyboard, 4 ms per matrix would be noticeably laggy, especially if you add debouncing (is that even a thing in keyboards?)

<comment><USER13> It's a microcontroller. It has maybe 512k of storage and 128k of memory. The Numpy package probably is ~100Mb

The controller is running CircuitPython which is a fork of MicroPython - <USER2> tiny re-implementation Python for microcontrollers.

<comment><USER12> Valid point! Might still be able to get a speed up if you can write and import your own C code though.

</comment></comment></comment></comment></comment><comment><USER14> Nice, if I made it I would replace the capslock with control and "~" with escape. Make the _least used_ keys require combinations, not the often used ones.

<comment><USER15> I use Caps Lock for both Ctrl and Esc, wouldn't have it any other way. Shift keys are also open/closing parens, holding down the tilde turns the "yuihjknm," section to a numpad, holding down Tab turns jkl; to {}[], etc.

Very handy when programming.

<comment><USER16> How's caps both ctrl and esc? Can you explain on shifts a bit? I guess you autotab

<comment><USER15> Oh, they're all hold/tap. Hold CapsLock to get Ctrl, tap to get Esc. Similarly with the shifts, hold to get shift, tap to get ( on left and ) on right. Tab is the same way, hold down tab to transform the keys.

<comment><USER16> Well, well.. why didn't I think of that! Thanks!

</comment></comment></comment></comment></comment><comment><USER17> Honestly, why Python? Writing a much faster equivalent in C really isn't any more complicated...

<comment><AUTHOR> Just for fun :)

The hardware includes a QSPI flash which presents as an USB storage that stored Python source code, and you can modify Python directly.

BTW, It provides a new way to validate your hardware product ideas quickly.

<comment><USER17> Solid answer. I just realised my question sounded cynical - which wasn't my intention.</comment></comment></comment>


Is there a 4th missing component in the mechanical world? - <AUTHOR> http://www.judegomila.com/2010/11/is-there-4th-missing-component-in.html#heyzap_game=

<comment><USER2> I've never been convinced that the memristor is worthwhile to consider as a "fundamental passive device" as everyone seems to want to claim. There are a few reasons for this:

(1) It's underspecified compared to the fundamental passive circuit elements. For linear R, L, and C, each has one parameter, its value. Ignoring trivial cases (viz., resistors), a memristor has as its memristance an arbitrary function of V and I. As a result, any interesting memristor is automatically not LTI.

(2) It's not particularly special. Why don't we also define a memcaptor, whose capacitance is a function of its current history? I could easily do this, for example, by making a capacitor where one plate is attached by a spring to a fixed support; then, by adding charge, I move the plate and increase the capacitance (or, by removing, I decrease it). Oh wait, that's just a nonlinear capacitor. In the same way, the memristor is just a funny name for a particular kind of nonlinear resistor.

(3) It's not particularly practical (for the moment). It can't be made in anything but a very specialized, presumably extremely expensive process. I hope this changes---I'm sure it'll encourage someone to use them!---but at the moment this really limits my excitement.

(4) There's nothing I can build with a memristor that I couldn't build already. This isn't like the invention of the vacuum tube: you give me a memristance function, and I can build you a pseudo-memristor out of transistors, Rs, Ls, and Cs. Yes, it could be less {space,power,?} efficient, but this is not a quantum leap in technology the way the vacuum tube was (one could not, with 1890s technology, reasonably build something that emulates a vacuum tube).

I'll admit that strictly interpreting my last argument, the vacuum tube could be made to emulate a transistor and thus the transistor wouldn't count as a quantum leap---clearly ridiculous. However, I'd contend that the real value of the transistor was only evident once it was sufficiently miniaturized and its production was sufficiently cheap. You show me memristors that are six orders of magnitude cheaper than transistors and by golly I'll be a convert. Even then, it'll just be yet another nonlinear device with which we can do interesting things---and just like the transistor, the memristor will simply never be as fundamental as R, L, or C.

<comment><USER3> Regarding your (1), I'm not sure I follow, isn't the fundamental unit of resistance, ohms, just a function of V and I? Namely V/A. Likewise for capacitance, the Farad is simply (A/V)s. Basically, your argument feels like it is begging the question -- we gave those functions of V and I names, so now they are fundamental units but not the memristor one... because it doesn't have a name?

<comment><USER2> No, there's a more intrinsic difference.

Resistor: V = I R

Memristor: V = I M(q)

The memristance is itself a function of the integral of I, and that function is arbitrary.

</comment></comment></comment><comment><USER4> Also see _What is the mechanical element equivalent of the memresistor?_

[http://www.quora.com/What-is-the-mechanical-element- equivale...](http://www.quora.com/What-is-the-mechanical-element-equivalent- of-the-mem-resistor?q=mechanical+equi)

<comment><AUTHOR> I sent him an PM. I'm sure there is a lot more to this!

</comment></comment><comment><AUTHOR> An inerter is the mechanical equivalent of a capacitor. <http://www.admin.cam.ac.uk/news/dp/2008081906>

<comment><USER5> I question whether the article is correct about the "J-Damper" being a meaningless code-name. In circuit theory, a capacitor can be thought of as a resistor with purely complex (and frequency varying) impedance. Since "J" is the standard symbol for the square root of -1, and given the fact that this device had never been used before, "Imaginary Damper" seems entirely appropriate.

<comment><USER6> It's actually J for "jounce" <http://www.f1technical.net/features/10586>

</comment></comment></comment><comment><USER7> Charge being equivalent to position doesn't make much sense to me.

When I learned systems modelling, we studied spring-mass-damper systems right next to electrical circuits and I have ever since thought of a capacitor as equivalent to potential energy, an inductor as equivalent to inertia and a resistor as equivalent to friction.

<comment><USER8> That's a common view, since force ~ voltage, current ~ velocity (i.e. charge ~ position) seems "intuitively" correct, but it breaks down when you look at what would be the equivalents of KVL and KCL. KCL states that currents sum to zero at a node in the absence of capacitance: this is similarly true of forces (capacitance in this case representing the ability of the node to change position/"charge").

KVL states that voltage differences sum to zero around a loop: this is similarly true of velocity differences. This can be difficult to visualize, but imagine a loop of N springs. Assume the loop can have no net translational motion (as above, this means it is not capacitive). Now imagine the different ways each spring can move individually. The loop could rotate as a whole, meaning half the springs have are moving "up" (i.e. have a positive voltage across them) and the other half "down" (i.e. have a negative voltage across them). The loop could be still, but for one element compressing and its neighbor expanding (i.e. all zero voltages with one positive and one negative).

The reason the examples in your systems class worked was likely because the circuits were simple enough that their duals shared the same, or similar, network structure. You can see this with a purely electrical circuit -- analyze a simple LCR loop, and then swap the L & C equations and you should get the same result. This breaks down for larger circuits, where you must find the dual network in addition to swapping Ls and Cs.

<comment><USER7> The invetor's slides say that the only time the analogy breaks down is with ungrounded capacitors, though its unclear to me what exactly that means (I don't really feel like thinking too hard about it). See slide 17 <http://www- control.eng.cam.ac.uk/~mcs/lecture_j.pdf>

There are actually a few different analogies you can make between electrical/mechanical devices. See the top table "Key Concept: Analogous Quantities". This is part of the reason why I don't feel like thinking too hard about what the inventor means when he says the analogy "breaks down" with ungrounded capacitors. [http://www.swarthmore.edu/NatSci/echeeve1/Ref/LPSA/Analogs/E...](http://www.swarthmore.edu/NatSci/echeeve1/Ref/LPSA/Analogs/ElectricalMechanicalAnalogs.html)

The inventor has created a "new analogy" where the inerter is a capacitor. I read your post as saying the old analogies don't work. Is that correct?

<comment><USER8> The point you're making is orthogonal to the one I was making: the force ~ voltage analogy breaks down at KCL/KVL (as well as ungrounded inductors), while the force ~ current analogy breaks down only for ungrounded capacitors.

"Ungrounded capacitors" refers to capacitors which do not have at least one terminal connected to the reference voltage (ground). These break the force ~ current analogy because with that analogy, capacitors, which are two-terminal devices, are analogous to flywheels, which are one-terminal devices. The velocity (voltage) of the second terminal is effectively zero.

Your reading of my post is close to correct. The force ~ voltage analogy is incorrect however you look at it because KCL and KVL don't hold. The "old" force ~ current analogy does hold except for the case of ungrounded capacitors, which the replacement of flywheels with inerters remedies.

</comment></comment></comment></comment><comment><AUTHOR> Another interesting question. Given we can move between mechanical and electrical systems with circuit theory. Are their other systems that we could apply circuit theory to (i.e. non electrical and non mechanical systems). Light and space circuits for example?

<comment><USER9> Audio Systems consist of electrical circuits (amplifier, player), mechanical circuits (loudspeaker-membrane) and acoustical circuits (air, room acoustics). All these parts can be modeled as circuits that directly interact with each other.

You can actually calculate the electrical properties of the mechano-acoustical loudspeaker+room or the acoustical properties of the electro-mechanical loudspeaker+amp. This is extremely helpful when designing loudspeakers since you can see the electrical, mechanical and acoustical properties all in one notation.

</comment></comment><comment><AUTHOR> From Prof. Malcolm Smith

"I have always thought that the memristor is rather a weak concept. It is defined as a device with a nonlinear relationship between flux and charge. A linear memristor is the same as a resistor, so in linear circuits the element is not meaningful. The definition does not pin down the type of nonlinearity. So the difference between a variable resistor and a memristor is not sharply defined. The mechanical equivalent of a variable resistor is of course a variable damper. Variable dampers and semi-active dampers are of course used a lot in suspension systems"

</comment><comment><AUTHOR> From a friend: "The quantum mechanics stuff sounds very unlikely. Although if you wanted to try and go in that direction you would have to figure out whether circuits have a strong analogy to the Hamiltonian formulation of quantum mechanics (i.e. no discussion of forces!) - then you would be in business. You could then probably formulate a "quantum circuit" in which measurements of voltage and current obey an uncertainty principle"

</comment><comment><USER10> What's an inerter?

<comment><USER11> See <http://en.wikipedia.org/wiki/Inerter_(mechanical_networks)>.

I am not too happy with that article; does anybody have a better source?

<comment><USER12> My own experience... I know why this concept sounds so familiar to me. I had one when I was little.

There are many childrens toys with a flywheel and a ripcord. That system is an "Inerter"... If the ripcord is a rigid toothed rack and pinion setup then it can act as an "Inerter" in compression as well as tension.

</comment></comment></comment><comment><USER13> It's "memristor", not "memresistor"

<comment><USER14> actually, both are acceptable terms

</comment></comment><comment><USER15> Why isn't an inerter just a flywheel?

<comment><USER8> Because flywheels have only one usable node; the other is effectively "grounded". They're also rotational; if you're working with translational systems (e.g. suspensions), you need something else.

An inerter, being basically a flywheel connected to a rack gear, meets both these requirements. You have two nodes (the flywheel's axis, and the rack gear) and the motion is translational.

<comment><USER8> Additionally: a rotational inerter can be made by connecting the ring gear of a differential to a flywheel. The two nodes are then the two side gears of the differential.</comment></comment></comment>


A guide to salary negotiation for women in tech - <AUTHOR> https://dmv.myhatchpad.com/insight/a-guide-to-salary-negotiation-for-women-in-tech/ <comment><AUTHOR> On average, women look for a 5% salary increase when applying to a new position, whereas men look for a 7% salary increase.

For example, a male senior developer would expect to go from $160k to $171k, while a female senior developer in the same position would seek to raise her salary up to $168k. That difference might not seem like much, but compounded year after year, it leads to the local gender pay gap that is close to 10%.</comment>


Margaret Hamilton, lead software engineer, Project Apollo - <AUTHOR> http://threefingeredfox.net/?p=143 <comment><USER2> Yes, she was one of the early formal-methods people. I met her and Saydeen Zeldin back when I was doing proof of correctness work. They had a company called Higher Order Software, which promoted an extreme form of waterfall design using formal methods. This is appropriate for avionics but didn't catch on. Proof of correctness was just too slow back then.

 _Incidentally, when you post articles like this, please don 't use a title that makes it sound like an obituary._

<comment><USER3> It's still too slow today for all but the most security critical applications.

Fortunately there is a lot of work in progress to improve the situation.

<comment><USER4> It's not too slow, it just takes discipline that most developers/companies don't have, primarily because the tools aren't widely available.

<comment><USER5> What do you mean by "not widely available"? Just as examples, Coq and Idris are both free:

[https://coq.inria.fr](https://coq.inria.fr)

[http://www.idris-lang.org/](http://www.idris-lang.org/)

Did you mean they're not in wide use?

<comment><USER6> I'm trying to install and use Idris as we speak. It seems to require learning two other languages (Haskell, PowerShell) first.

<comment><USER7> PowerShell? That's a new one....

I haven't used Idris, but as a proof assistant, Coq is one of the best computer games I know[1]. As a programming language, it's a very good proof assistant.[2]

[1] Really! It's fun. I've found the resulting proofs impossible to read, though. The closest description I can make is that they're programs for a stack machine; reading those is not a skill I've developed.

[2] All of the dependently typed languages, like Coq, that I've seen have not been very good programming languages, in my opinion. Except for ATS, which I don't think is a good programming language for different reasons. But I really like it, anyway.

<comment><USER6> > All of the dependently typed languages, like Coq, that I've seen have not > been very good programming languages, in my opinion.

Yeah, that's why I'm looking at Idris - it seems like the only one that's oriented towards practical programming. I did eventually get it installed, but it's tough going doing anything with it when you don't know Haskell tbh.

<comment><USER8> > Idris - it seems like the only one that's oriented towards practical > programming

Whether you like ATS or not, it's very oriented towards practical programming. Also, ATS mostly looks bad IMO because of the style the author uses.

I still haven't fully formed an opinion on ATS though. Idris does seem really cool and stuff like enforcing time/space usage through the type system excites me.

<comment><USER7> I'm not sure whether my issue with ATS is the style of the author or its type system, although I suspect the former.

ATS is based on ML (the author started with Dependent ML), but the code has a very imperative feel, leading to statements like "let () = expr() in ..." and "let x = ... in ()".

The stuff at [http://www.ats-lang.org/Examples.html](http://www.ats- lang.org/Examples.html) is just hideous, by the way.

<comment><USER8> I agree with you, though I think it is because of the authors style. Check out some of Chris Done's ats code examples in a more appealing style:

[https://gist.github.com/chrisdone/c23251e8b975dc805876](https://gist.github.com/chrisdone/c23251e8b975dc805876)

</comment></comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER9> I worked with Margaret and Saydeen at Higher Order Software for my first job out of college, but I didn't get to work on anything as glamorous as Apollo. We did mostly government contracts; I was there for two years before I decided it was time for grad school.

<comment><USER10> Is HOS what it seems? I read about it years ago in "System Design from Provably Correct Constructs". It seems like it should revolutionize software development (and incidentally put most programmers out of business) but that it somehow just never gets "traction" beyond certain markets/customers?

<comment><USER11> The first time -- and still one of the few times -- I ever walked out of a meeting because the BS level seemed too high was when I visited Higher Order Software in the 1980s.

<comment><USER12> Can you please share details of what caused you to walk out? There is a lot of curiosity around USL and the toolchain she and her team have built, but my Google-fu has failed to come up with descriptions of practical experience with them. I'm struggling to decipher how different it is from UML, or what it is solving that functional approaches are not already working to address.

<comment><USER11> It was 30ish years ago, so I don't recall details. But it seemed overhyped. The usual problem with tools that do a great job of generate code is that they do a great job of generating CERTAIN KINDS of code, but are unhelpful or even counterproductive with other parts of your development task. Certainly this was true in the 1980s, and back then the problem was exacerbated in that there weren't graceful ways to combine what was generated with what you had to write or modify by hand.

<comment><USER10> Okay but _was_ it BS, or did it just _sound_ like BS and actually it's important and useful (if a bit rough and early)? That's my main curiosity.

</comment></comment></comment></comment></comment></comment><comment><USER13> I find it a bit... sad? disturbing? that the only reason women were so involved in computing and programming in the early years was because programming and software were seen as less important jobs than the "software planner" jobs, where the "coder" was just a flunkie, something of a software custodian. They were considered clerical jobs, like data entry or a secretary.

This old article (2009) has a lot more details on this old sociological phenemonon:

[http://homes.soic.indiana.edu/nensmeng/files/ensmenger- gende...](http://homes.soic.indiana.edu/nensmeng/files/ensmenger-gender.pdf)

The author has a whole blog about this topic:

[http://thecomputerboys.com/?p=239](http://thecomputerboys.com/?p=239)

<comment><USER14> I started programming before I was a teenager, in part because my mother was a programmer. At that time, 30+ years ago, women were not programmers because it was "less important". You didn't see men taking programming jobs as a "Consolidation" for some better career.

My first two programming teachers- in college and in high school- were both women who were also professional programmers at previous jobs.

It was a prestigeous job, as the computer was seen to clearly be the herald of a new age. The personal computer revolution was really significant. It was a job for smart, mathematically inclined people.

I think programming is seen as a lower status job now than it was then. Now programmers are subservient to ignorant business people (When the reality is, its much easier for use to learn business than them to program.)

I think in the past women were more likely to be programmers because the profession didn't have a gender stigma. Because men were more likely to have picked out a profession, and women who entered college without a specific degree plan were more likely to pick this one up.

And frankly, I've never seen a problem with women programmers. I've worked with women programmers at every job where there were more than 10 programmers, and they haven't been seen as deserving, or treated with less respect... this goes back to the 1980s.

I would like you to back up your assertion that the "only reason" they were involved was low status. That paper you linked to is fallacious beyond belief. You may disagree with my anecdotes below, but he's merely giving us his spin on an article. (So he's not only anecdotal, but derivative.)

<comment><USER13> > 30+ years ago

That's barely in the 1980's or late 1970's, well after the events being described in the articles I mentioned.

Can you contest that Von Neumann considered programming a clerical job?

> That paper you linked to is fallacious beyond belief.

Well, I suppose I would have to read his citations too, to check if they were all lies as well.

<comment><USER15> If you're going to make a list of people that John von Neumann looked down on, it's going to be rather longer than just women (try anyone who wasn't as smart as he was, which is just about everyone).

Brilliant scientist. World-class ego.

</comment></comment></comment></comment><comment><USER16> Definitely a role model.

Her site has a pretty neat article called "Inside development before the fact":

> Today's traditional system engineering and software development environments > support their users in "fixing wrong things up" rather than in "doing them > right in the first place". Things happen too late, if at all. Systems are of > diminished quality and an unthinkable amount of dollars is wasted. This > becomes apparent when analyzing the major problems of system engineering and > software development.

Also a cool paper she wrote:

> The key to software reliability is to design, develop, and manage software > with a formalized methodology which can be used by computer scientists and > applications engineers to describe and communicate interfaces between > systems. These interfaces include: software to software; software to other > systems; software to management; as well as discipline to discipline within > the complete software development process. The formal methodology of Higher > Order Software (HOS), specifically aimed toward large-scale > multiprogrammed/multiprocessor systems, is dedicated to systems reliability. > With six axioms as the basis, a given system and all of its interfaces is > defined as if it were one complete and consistent computable system. Some of > the derived theorems provide for: reconfiguration of real-time > multiprogrammed processes, communication between functions, and prevention > of data and timing conflicts.

[http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=170233...](http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=1702333&tag=1&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D1702333%26tag%3D1)

And some NASA work related to HIOS: [http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/1975001...](http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19750010848.pdf)

</comment><comment><USER17> Besides the great photo and backstory, I liked this snippet:

> _She was all of 31 when the Apollo 11 lunar module landed on the moon, > running her code. (Apollo 11 was able to land at all only because she > designed the software robustly enough to handle buffer overflows and cycle- > stealing.)_

You could read that paragraph in several ways. Back then, accomplishing something like that at 31 seems precocious. Today, in the hype about 18-year- olds becoming millionare-startup founders, she sounds like a late bloomer of a programmer.

<comment><USER18> More detail on the cycle-stealing bit, which caused an alarm during the Apollo 11 lunar descent, which the AGC's priority scheduling allowed it to recover from: [http://en.wikipedia.org/wiki/Apollo_Guidance_Computer#PGNCS_...](http://en.wikipedia.org/wiki/Apollo_Guidance_Computer#PGNCS_trouble)

<comment><USER19> Some years ago, there was a video about the moon landing in Washington DC airport (it was at a Smithsonian exhibit or store or some such). It included video of the control room when the alarm went off during descent. There was silence and blank faces - nobody knew what to do.

But by the time the alarm went off the second time on descent, it was completely different. Someone - whoever was in overall charge - called a role (something like "descent control officer") and that person responded "go", all within one second.

But, yes, it wasn't a problem because the priority scheduling recovered from this problem, and that recovery was a really big deal.

<comment><USER20> > _Some years ago, there was a video about the moon landing in Washington DC > airport (it was at a Smithsonian exhibit or store or some such). It included > video of the control room when the alarm went off during descent. There was > silence and blank faces - nobody knew what to do._

You have to be careful interpreting something like that. Without the backstory, you run the risk of projecting your own emotions onto the events.

Mission Control was actually _not_ very worried about the program alarms. According to Gene Kranz in his memoirs, the white team had been fed a program alarm during a pre-flight simulation. In fact, it was the _last_ simulation they ran through before launch, so it was fresh in their minds.

During the simulation, Mission Control incorrectly called an abort. During the debrief, the instructors told them that the program alarm was non-fatal, and they should have continued to a lunar landing.

During the actual lunar landing, Mission Control was astonished to run into the same scenario. It was like running through the simulation a second time.

> _But by the time the alarm went off the second time on descent, it was > completely different. Someone - whoever was in overall charge - called a > role (something like "descent control officer") and that person responded > "go", all within one second._

Neil Armstrong did have to ask twice, but he did get a response from Mission Control on the first alarm. Mission Control did not ignore the first alarm.

The delay was caused by having to consult a list of fatal and non-fatal program alarms. Once they had that list, it was easy to call a Go on subsequent program alarms. However, they couldn't just give a Go to the first alarm without checking the list.

Armstrong and Aldrin hadn't participated in that earlier simulation, so they were probably a lot more worried than Mission Control was!

Here is the transcript with references to Kranz's book: [http://www.hq.nasa.gov/alsj/a11/a11.landing.html](http://www.hq.nasa.gov/alsj/a11/a11.landing.html)

</comment></comment></comment></comment><comment><USER21> It looks like she is currently CEO of a company that sells a formal-methods language (and accompanying IDE) called 001. It looks interesting - has anyone here worked with it before?

[http://www.htius.com/](http://www.htius.com/)

</comment><comment><USER22> More details about her work on Apollo Guidance Computer:

Apollo Guidance Computer History Project, Margaret Hamilton's introduction:

[http://authors.library.caltech.edu/5456/1/hrst.mit.edu/hrs/a...](http://authors.library.caltech.edu/5456/1/hrst.mit.edu/hrs/apollo/public/conference1/hamilton- intro.htm)

"Many of the things I was intrigued by had to do with how to make the mission software safe and reliable. And one of the things I remember trying very hard to do was to get permission to be able to put more error detection and recovery into the software. So that if the astronaut made a mistake, the software would come back and say "You can't do that." But we were forbidden to put that software in because it was more software to debug, to work with. So one of the things that we were really worried about is what if the astronaut made a mistake -- We were also told that the astronauts would never make any mistakes, because they were trained never to make mistakes. (Laughter)

So we were very worried that what if the astronaut, during mid-course, would select pre-launch, for example? Never would happen, they said. Never would happen. (Laughter) It happened."

She also mentions her companies:

"So since that time, the theory has evolved and now I actually lost the first company to venture capital people, and started a second company called Hamilton Technologies."

The link to the second:

[http://www.htius.com/](http://www.htius.com/)

</comment><comment><USER23> The wikipedia article on her notes she's credited (by NASA) with coining the term "software engineering".

[http://en.wikipedia.org/wiki/Margaret_Hamilton_%28scientist%...](http://en.wikipedia.org/wiki/Margaret_Hamilton_%28scientist%29)

<comment><USER24> Interesting, and something I didn't know. The cited source unfortunately doesn't elaborate on the context. The chronology does seem about right. The first in-print use of the term I can find is from 1969, when it was used as the title for the proceedings of an October 1968 NATO scientific conference: [http://dl.acm.org/citation.cfm?id=1102020](http://dl.acm.org/citation.cfm?id=1102020). Given the NASA/NATO personnel overlap at the time, it's certainly plausible that they got it via NASA.

</comment></comment><comment><USER25> She was briefly mentioned in Steven Levy's "Hackers", as an MIT computer user who's program crashed after the "Midnight Wiring Society" changed how the computer worked.

Also, she was interviewed in "Moon Machines" episode three, about the nav computer.

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

</comment><comment><USER26> Awesome. She's a role model for girls, which our field badly needs. The client list on her company's website is pretty long and substantial.

<comment><USER27> She's a role model for everybody!

<comment><USER28> Sure, but we men already have plenty of computing role models. This is a welcome change.

<comment><USER27> Both female and male computer scientists need good female role models, and for the same reasons. In my own life I've been very fortunate to have been influenced by my mother (who taught me to program at an early age), by a grade school computing teacher (who also encouraged me to learn programming), and by my wife (a professional software engineer, among other things). I like to think that my wife's professional career has given my kids some similar perspective - even if only to change their unconscious assumptions about what women can do (which is everything, since my wife has been a writer, a software engineer, a business analyst, and a small business owner - and that's just what she's done professionally). Women needs to believe that they're capable of everything, and men need to believe that women are capable of everything, too. The same goes for men about men, and women about men. Feminism isn't about replacing patriarchy with matriarchy. It's about egalitarianism for all genders. That's all I meant.

</comment></comment></comment></comment><comment><USER29> What a truly inspiring human being. I can only dream of aspiring to her levels of contribution.

Check out some of the Apollo 11 code for the Lunar Module's (LM) Apollo Guidance Computer (AGC). It's just awesome browsing through it, reading the comments, and thinking about the zeitgeist of being on a team that was working on something of that world-altering magnitude.

Code Library:

[https://code.google.com/p/virtualagc/source/browse/trunk/Lum...](https://code.google.com/p/virtualagc/source/browse/trunk/Luminary099)

 _KALMAN_FILTER.agc_

[https://code.google.com/p/virtualagc/source/browse/trunk/Lum...](https://code.google.com/p/virtualagc/source/browse/trunk/Luminary099/KALMAN_FILTER.agc)

 _LAMBERT_AIMPOINT_GUIDANCE.agc_

[https://code.google.com/p/virtualagc/source/browse/trunk/Lum...](https://code.google.com/p/virtualagc/source/browse/trunk/Luminary099/LAMBERT_AIMPOINT_GUIDANCE.agc)

 _LANDING_ANALOG_DISPLAYS.agc_

[https://code.google.com/p/virtualagc/source/browse/trunk/Lum...](https://code.google.com/p/virtualagc/source/browse/trunk/Luminary099/LANDING_ANALOG_DISPLAYS.agc)

 _LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc_

[https://code.google.com/p/virtualagc/source/browse/trunk/Lum...](https://code.google.com/p/virtualagc/source/browse/trunk/Luminary099/LUNAR_AND_SOLAR_EPHEMERIDES_SUBROUTINES.agc)

 _LUNAR_LANDING_GUIDANCE_EQUATIONS.agc_

[https://code.google.com/p/virtualagc/source/browse/trunk/Lum...](https://code.google.com/p/virtualagc/source/browse/trunk/Luminary099/LUNAR_LANDING_GUIDANCE_EQUATIONS.agc)

\- - -

Incredible quote:

"There was no second chance. We all knew that. We took our work very seriously, but we were young, many of us in our 20s. Coming up with new ideas was an adventure. Dedication and commitment were a given. Mutual respect was across the board. Because software was a mystery, a black box, upper management gave us total freedom and trust. We had to find a way and we did. Looking back, we were the luckiest people in the world; there was no choice but to be pioneers; no time to be beginners." \- Margaret Hamilton

\- - -

Edit: OK, this is interesting. Note the filename. The filename and comments suggest that it was for driving keyboard and information display...

 _PINBALL_GAME_BUTTONS_AND_LIGHTS.agc_

[https://code.google.com/p/virtualagc/source/browse/trunk/Lum...](https://code.google.com/p/virtualagc/source/browse/trunk/Luminary099/PINBALL_GAME_BUTTONS_AND_LIGHTS.agc)

<comment><USER16> I'm having a hard time believing that's a working kalman filter implementation in assembly in 70 odd lines!

<comment><USER29> Check this out... here are the two source code pages (digitized from original printouts) for the Kalman filter, dated July 14, 1969!

 _KALMAN FILTER USER 'S PAGE NO. 1_

[http://www.ibiblio.org/apollo/ScansForConversion/Luminary099...](http://www.ibiblio.org/apollo/ScansForConversion/Luminary099/1470.jpg)

 _KALMAN FILTER USER 'S PAGE NO. 2_

[http://www.ibiblio.org/apollo/ScansForConversion/Luminary099...](http://www.ibiblio.org/apollo/ScansForConversion/Luminary099/1471.jpg)

<comment><USER30> According to wikipedia "The onboard guidance software used a Kalman filter to merge new data with past position measurements to produce an optimal position estimate for the spacecraft." [https://en.wikipedia.org/wiki/Apollo_PGNCS](https://en.wikipedia.org/wiki/Apollo_PGNCS)

In turn the main source of navigation information came from mission control using least squares. A source on that would be nice too!

</comment></comment></comment></comment><comment><USER31> When this story was posted yesterday [1], the comment about UDL sparked my interest. That led me to Hamilton's _Development Before the Fact_ methodology [2]. I find DBTF an appealing approach to reliable systems, particularly buildings. Because AEC design software is largely focused on automating manual steps rather than the generation of systems.

[1] [https://news.ycombinator.com/item?id=8731711](https://news.ycombinator.com/item?id=8731711)

[2] [http://www.htius.com/Articles/Inside_DBTF.htm](http://www.htius.com/Articles/Inside_DBTF.htm)

</comment><comment><USER32> > I suppose today's kids are ho-hum about these recoveries of memory, but I > think they're pretty neat.

No, we think they're pretty neat too :-)

</comment><comment><USER33> In early computer days a fair fraction of the programmers were women. They migrated from earlier computer jobs such as keypunch operators, switchboard wirers (some early computers had programable switchboards) and mechanical calculator clerks. Until mid 1940s "computer" meant the third category- a person who operated mechanical calculators.

</comment><comment><USER34> I hope this serves as tangible evidence that women do have their place in tech. I feel it's a shame that we believe (rightfully or not) that we need extra coding schools for females.

</comment><comment><USER35> My take on this: If more women would be into (information) technology, we would have cheap holidays on Mars!

Margaret's role is a role model.

</comment><comment><USER36> what a great read. she looks so happy! she is very pretty as well!

</comment><comment><USER37> Her with a hardcopy of her code.

[http://i.imgur.com/bxyWmuA.jpg](http://i.imgur.com/bxyWmuA.jpg)

<comment><USER36> shes brilliant and gorgeous. I don't see anything wrong with that</comment></comment>


Ask HN: How many of you are actively using scrum/agile methods? - <AUTHOR> To me it seems like scrum/agile methods are things only used in bigger companies where productivity/motivation of employees might be a big issue - even the quality of the employees. Every time I hear those terms I just get a shiver all over my body, but you still hear them used quite a lot in the software business.
I've never heard of anybody talking about those things in the startup world to any extent. Are those methods useful in the startup context? Do any of you guys actually use them? <comment><USER2> Scrum is a trick to get everyone into the office by 9 am. Agile is a disguised form of extreme micromanagement.

Both techniques have been cleverly marketed as a way for developers to work together in a state of harmonious productivity, when really they are CYA tools for managers.

<comment><USER3> Amen. They are slave-driven development methodology.

<comment><USER4> Wow you guys have no idea. Please, just because some loser used it as an excuse to be a slave driver, don't blame agile/scrum.

Daily stand up meetings should happen whenever everyone will already be there. 9 is irrelevant. 10 is fine. If someone is WFH, then they call in.

Agile saves me FROM the micromanagers. Instead of having to be polled every few minutes, go look at the freaking board! Finally, no interruptions...

</comment></comment></comment><comment><USER5> I use fixed sprint lengths (3w) with fixed team members, and a backlog of time estimated items that the product owner prioritizes.

I would not go back to not doing this, as it allows focus (sales people fight to get things into the backlog and next sprint, rather than grabbing a developer directly). It discards out of the blue time estimates ("oh, maybe 3 months?"), by rejecting everything longer than the sprint. It also foster better developer-tester communication inside the team, already during development, which kills bugs earlier.

We're currently 3 teams with 5-6 developers and 1-2 testers each, soon to split into 4 teams and 2w sprints. So yeah, bigger company,

Agile killed a previous waterfall model with 2 month spec creation/review, 2-3 month development phase with developers being added and taken away during the time, and 1-2 months of testing, followed by bug fixing by developers that were taken out from other projects started by then.

</comment><comment><AUTHOR> Personally, if I was looking for a job and scrum/agile was mentioned in an ad, it would be enough for me to not even consider the posting.

<comment><USER6> I agree with this. I was lead designer in a team developing a multi-format game about 3 years ago. We switched to using agile and it really hit relationships and the way we worked in the team.

Rather than the lead programmer, artist, designer, and producer having a good picture of the development process, the project manager was the only one who had a view on where we were in the project. He was not from the games industry which made it even more difficult.

We were only using a subset of agile, but it seemed to break up the team rather than get them working together.

I'm not saying this is the fault of the agile method, or that agile is wrong for games development, but in my experience it was enough never to want to use it again.

<comment><USER7> What did you switch from? Which agile method did you use?

<comment><USER6> We switched from a system that had just worked organically over several previous projects. Weekly meetings among the leads with the producer and project manager. Each lead would work out the tasks, time limits, and take into consideration other departments deliverables. Inter-departmental communication was also handled by the leads, there was no pairing off, or groups of different disciplines working together, although this did happen when necessary throughout a project.

As for what Agile method we used, I have no idea what specifically the method was called. We were told our team was going to experiment with Agile but keep it very simple. Teams of 2 or 3 were formed for specific tasks from different departments. Weekly time slots allocated, and reviews done at the beginning of the following week.

</comment></comment></comment></comment><comment><USER8> I work in a really small team of 2. So we just have a large todo list.

I work with my girlfriend so we talk about ideas, implementations and goals almost all the time.

Even when we get bigger (And I hope we do), I would really prefer not to abstract things too much, KISS.

<comment><USER5> Sounds quite agile. Set a spring length, time estimate and prioritized the todo list. Then you would get a pulse between developing and reviewing what time is spent on and if you're developing the right things.

<comment><USER9> If people call any simple style of development/review that works "agile", then what about when developers go through the motions to do "real" Agile Development (TM) and it doesn't? Is that not "agile" anymore?

That's like when TDD advocates claim credit for the benefits of doing _any testing at all_ , but only acknowledge the costs of doing orthodox TDD (if that). It's dishonest, and makes it harder for anyone to have any kind of meaningful discussion about what does and doesn't work.

I'm not arguing that there's a benefit in having a development / testing / review cycle, but when discussion turns to capital-m Methodologies, it tends to become us-versus-them, more about following the methodology's branding and other trappings to the letter than whether things actually work.

[Edited a bit for tone, and to make it less personal]

<comment><USER5> I did nothing intentional there really. You seem to be making me defend some brainchild of yours about what "Agile Development (TM)" is. I wont go there. Nor will I be associated by TDD advocates that you don't like.

I just find pistoriusp to be quite agile in that they see themselves as a team, and that they have a todo list of things to finish in some order (backlog in agile terminology).

Since I am being down voted, there must be people that think it is a bad idea to introduce a fixed sprint length and perform time estimates on todo list items. For the conversation, I want to hear those arguments.

<comment><USER9> First, it sounds like that wasn't your intention, so sorry for putting you on the spot.

I don't care about Agile Development, proper. I want people to be able to discuss what techniques increase agility (which needs a better word, now) without the Agile people stepping in and derailing everything into being about their personal ideology.

I just think the advocacy tactic of, "You've been unknowingly following my Special Technique all along, and that's responsible for your success...do it _right_ and you'll do even better" should be seen for what it is: taking all of the credit and none of the blame.

And about, "You hate Agile, so you must think waterfall is better"? Don't get me started.

</comment></comment></comment></comment></comment><comment><USER10> We (we're two) use some form of scrum which vary over time, to handle our mix of billable work + self projects.

It's always extremely beneficial in our case (and not about motivation).

Things I really appreciate:

\- product-owner mindset is the most beneficial to us: things like theme scoring <http://www.mountaingoatsoftware.com/tools/theme-scoring> or other techniques advocated by Mike Cohn

\- writing user stories + role modelling is really helping us "go out of the garage"

\- burn down charts and estimation techniques provided by Mike Cohn help us a lot ensure we deliver on time/budget

\- we know where we stand (what's remaining, etc)

So my conclusion: a lot of people these days are avoiding scrum/agile because they are used as buzzwords. It shouldn't make you miss the (extremely) useful tools they provide...

In any case - yes, I'm very actively using all this!

</comment><comment><USER11> We have five engineers on our team, and eleven in the company (I think? I forget if we hired one more in Colorado).

We use a somewhat-modified scrum. Stand-up meeting daily at 10am, board with hour-estimated tasks divided into stories that migrate from on-deck to in- progress to done. We also have a nice burn-down chart (on paper, updated with markers by hand) that we update daily.

Overall, it works quite well for us. The businesspeople can easily check the chart for a "where are we on this stuff?" question, so they like it. The task board and chart are good for similar things for us.

We modify how we do it just a little every iteration, but it does keep working better. For instance, how do we managed added tasks on the burndown chart? Do we adjust the red and green lines and deadlines? Do we have a separate "tested automatically" category on the task board to assess test coverage for the story? But it's little stuff like that, window dressing, that we tend to adjust. Overall it's working quite well for us.

</comment><comment><USER12> My company does outsourcing, mostly with startups. We use scrum (the management framework) and lots of extreme programming (technical practices), all of which fall under the broader "agile" (abstract concepts). We do these on every one of our projects...from 2 person iPhone apps to year long, multi- team projects.

For any group of people that's going to work together and produce, the ideas in scrum and agile are super important. Apply them how you like, using whatever names you like, but understand them and be aware of which ones you're doing

To me, scrum is barely a process, and it won't solve any of a group's problems...but if it's applied at all it will make those problems really obvious, at which point it's up to people to fix them.

</comment><comment><USER13> I would not rely too much on these terms, every company has its own process that evolves. Agile and Scrum can assist in finding out what kind of a process you want to develop. There is nothing called "Scrum" that will fit all software companies.

</comment><comment><USER14> It's helpful to distinguish between big-a "Agile and little-a "agile"

"Agile" is all about orthodoxy. You must do A, B, and C.

"agile" is all about time-boxing and inspect-and-adapt. You can use anything you want.

I don't know why you wouldn't do agile, but I can imagine lots of folks will tell you horror stories about Agile.

I'm a big agile fan. Make a post-it when I think of a new feature. Stick it up on the wall. Every Wednesday I step back and take a look at the storyboard and what got done that week.

I mean really, isn't this just common sense? You have to do _something_ that's kind of project-management-y, why wouldn't you want to do the types of things that are as lightweight as possible?

</comment><comment><USER15> I'll add a contrarian view about Agile in big companies--I consulted for a major media company in NYC that used Rally and "did Agile" but it was mostly lip service and the daily scrum meetings were more like status reports. It was their sheer size and the inability of their project managers to adapt to a non-status-report mode of thinking that made the Agile methodology weak and unsuccessful.

I'd say Agile is much more easily adopted in a startup where no prior culture exists to inhibit it. Major companies with older systems in place don't change overnight.

</comment><comment><USER4> The methods are way useful anytime you're building software. The whole agile/lean methodologies was actually a grassroots movement that started in smaller teams and startups and had to be pushed into the enterprise world by activists. I can understand your comment about shivers because by now it's become a full on buzzword and lots of business people use them without having any idea what they're talking about.

If you can ignore the empty hype, there is still a lot of value in the actual practices. A lot of the practices are things that startups do naturally because it fits well. Iterating quickly, continuous integration and deployment, automated testing, user stories.

"Agile" is a movement, for lack of a better word, based on doing more of what works (focusing on people and productivity) and less on what doesn't (bulky processes). It was a reaction to the heavy waterfall, process-centric methods used that were slowing productivity down to a halt. Now that people who love paperwork have gotten their hands on it, they want to turn agile into something it's not. Anyone who tells you that you HAVE to do X, Y, and Z processes to be agile is wrong. It's about works best in your team and being open to trying new things to find out what that best thing is.

</comment><comment><USER16> Iterative development works and anything complex that works was built off a series of small things that work. Agile is simply a set of core principles like "satisfy the customer", "welcome changing requirements" and "working software is the true measure of progress". Scrum is simply a framework of team commitment and forces frequent communication (one of the principles). Typically if people complain about agile or scrum it is because they really do not understand that iterative development is and has been done for years and recognizes that requirements are perishable and maintaining them expensive and wasteful. The list goes on and on but if you understand agile as principles and values you would be hard pressed to disagree with any of them. Most managers do not get it though so the better question is "what practices do you use to be agile?" and you'd better damn well hear TDD, XP, BDD, Continuous Integration, etc.

</comment><comment><USER17> I don't work in a start up (hope to one day).

We use Agile - had been using Scrum, just moving to Kanban.

I find Kanban A LOT better for a cross discipline team (editorial, UX and tech) - but not been using it that long.

Yes it's working for us in a very large company, in a smaller privately owned company, where everyone's ass is on the line, maybe it wouldn't be so useful.

I do see the boards (scrum/kanban) as being a great way to surface what is happening in the team, to answer questions and show bottle necks. But in a smaller team that should just happen.

I think it can be used 'wrongly' to try to control teams, but i see it as a stakeholder management tool - "ok so you want that extra feature, lets go put that in the backlog, hum now see how our dates move? Ok you do, great, so what is your priority (considering we have fixed time)..."

</comment><comment><USER18> I work for a startup and we scrum every morning. We have some people working remotely so it's a good chance to get everyone on the same page.

Agile - I don't even know what that means. Different people use it differently. So yeah - uh - we're agile.

</comment><comment><USER19> We use daily standups, user stories, CI, and TDD. We're NOT pairing, keeping a burn down chart, or doing a great job of having regular retrospectives or iteration planning.

Our customer rep is someone who worked in the industry for several years before joining us as a salesman. He's now our fulltime customer rep/product owner for the team. So far that's going well he's a new addition so there's still time for it to go really good or really bad.

We're not an a startup, rather an established company with a successful line of products. The project I'm thinking of however is a brand new product that's been given a lot of leeway and autonomy.

</comment><comment><USER20> We use rally at work.

The best thing about rally is the short dev cycle and the often re-evaluation of our progress, etc.

Everything else seems like management rah-rah stuff, though.

</comment><comment><USER21> I know a lot of startups that do Scrum. It's helpful getting everybody on the same page and getting motivated.

Why do you get shivers? What's so bad about it?

Scrums and startups do mix.

[http://sfbay.craigslist.org/search/jjj?query=scrum+startup&#...

</comment><comment><USER22> Readness.com goes by the JFDI method:

Listen

Code

Ship.</comment>