Hacker News Reader

nimoson Modeled impact of large-scale wind and solar farms in the Sahara

The coefficient of performance (efficiency) of an AC at that temperature range would still be well over 1. Probably around 3-4 depending on the unit and refrigerant. [0] ACs are very efficient for the same reason heat pumps are efficient. They are just moving energy around.

[0] https://www.researchgate.net/publication/242172797_A_Compari...

nimoson Slow leak detected aboard Space Station

Interesting that they don't seem to have any kind of dedicated "patch kit" ready to go for stuff like this.

nimoson Using AWS EC2 instance store vs EBS for MySQL

Doesn't really seem like a fair comparison since it relies on compression for the local storage to be cheaper. Comparing similarly sized EBS volumes + EC2 instance to the local storage instances and it is pretty much the exact same cost.

Obviously local NVMe is going to smoke a networked replicated drive performance wise but that comes with it's own set of trade offs.

nimoson Horrors of Using Azure Kubernetes Service in Production

Interesting. The kubelet seems to use varying negative OOMAdjusts to prioritise killing[0] but if I'm reading the kernel code right anything at -999/-998 would return 1 from the badness function and essentially be equally valid to kill unless it was using over 99.9% of available memory.[1]

I see OOMScoreAdjust=-999 for kubelet being used but why not -1000. -999 seems like it would be equally likely to be evicted as -998 unless the for_each_process(p) macro always goes first to last processes?

[0]https://github.com/kubernetes/kubernetes/blob/master/pkg/kub...

[1]https://elixir.bootlin.com/linux/latest/source/mm/oom_kill.c...

nimoson A $3B Plan to Turn Hoover Dam into a Giant Battery

26/15 is the estimated cost per kwh. Really there is a huge variance, especially for pumped storage because because of highly variable capital cost.

Capital costs are in the 100s-1000s dollars for kw of pumped storage.[0]

[0]http://large.stanford.edu/courses/2014/ph240/galvan-lopez2/

nimoson China is making electric buses cheap, just like it did for solar panels

I wish they would make self attaching electric/battery trolley busses. The main lines on the streets in Vancouver aren't bad but the intersections are such a mess with the trolley lines. You could min-max a system that combined trolley lines with batteries and use much less of both. Put the starts above bus stops so they don't have to attach at speed and you get to cover the initial expensive acceleration too. Back of the envelop guess from supercharger times is you would only need 10-20% of the routes actually covered in lines to maintain battery charge.

It'd also be nice if more of the self driving companies would go after busses first. Fixed routes seems like a significantly easier problem and you can amortise all your sensor/electronic cost over a more expensive vehicle.

Both combined would pretty radically alter the environmental and economic cost of public transportation.

nimoson Apple Partnered with Blackmagic Design on an External GPU for MacBooks

Considering it is larger than some mini PCs with 1080s in them I'd really hope not.

nimoson Microsoft has sunk a data centre in the sea to investigate energy efficiency

Not to mention all the extra CPU load the tracking and JS spam causes on everyone's phones and computers.

nimoson Show HN: Wired-elements – UI web components with a hand drawn, sketchy look

Love this. I wonder if there would be a way to add some randomisation to the font without replacing it with generated images.

nimoson Regional Persistent Disks on Google Kubernetes Engine

https://cloud.google.com/compute/docs/disks/#introduction

Only difference in docs is 1/2 the write throughput per GB on SSDs. Latency is probably the real issue though. Kind of annoying that neither pricing or performance is even mentioned. Pricing is at a "promo" price of .24 a GB for SSD and .08 for standard.

nimoson Silicon Valley tech bubble is larger than it was in 2000, and the end is coming

Ah yeah my bad, its per week, page 16 in pdf pages.

nimoson Silicon Valley tech bubble is larger than it was in 2000, and the end is coming

I'm happy as the next person to eye roll a lot of the stuff that gets funded but the world is just fundamentally different compared to 2000. The average time an internet user spent online at home was ~3 hours in 2000 and is about 18 now.[0] People are just so much more willing, and able, to spend time and money online now days I would be surprised if there was 2000 style crash.

[0]http://www.digitalcenter.org/wp-content/uploads/2013/10/2017...

nimoson Stateful Apps on Kubernetes: A quick primer

Hard to say without knowing what they ran on what. There is a non trivial amount of memory that gets eaten up by the various k8s processes, docker and networking if you are using small nodes. I have a completely empty k8s cluster up right now with 1 worker and 1 master and the worker has about ~230 mb of ram used up.

nimoson Intel's 10nm Is Broken, Delayed Until 2019

I think 2019-2020 will be super interesting for hardware. Intel, Samsung, Gloflo, TSMC could all have competitive 7/10nm nodes. Unless either Intel or AMD makes some crazy IPC gains they should be fairly competitive with each other and it will be interesting to see what the ARM giants can do as well. Hopefully Chinese investment into DRAM/NAND starts to come to fruition by then too.

nimoson Is sorted using SIMD instructions

Isn't that just a prefetcher win? AVX/SSE lets you do more computational work per cycle but I don't see how it would improve memory bandwidth/access.

nimoson Is sorted using SIMD instructions

I'm pretty sure each core has its own AVX units for the version they support.

AFAIK the only difference between AVX performance (ignoring clock speed) is gold/platinum(5000+) Xeons have 2x512 FMA ports available but everything else only supports FMA on port 1/2 and not 5. Stabbing a bit in the dark here, it's been a bit since I was looking at this stuff.

nimoson Ask HN: What are the best MOOCs you've taken?

Balaji and Vijay version actually. I think it was only actually offered once on Coursera.

nimoson Facebook CEO says no plans to extend all of GDPR globally

I wonder what the minimum amount of work you have to do to get GDPR to apply to you. Is it EU citizens only? Or would residency work?

I doubt it, but it would be interesting if Estonia's e-residency thing would be enough.

nimoson Examples of everything new in ECMAScript 2016, 2017, and 2018

There is a proposal out for it:

https://github.com/tc39/proposal-optional-chaining

nimoson Programming language versioning bothers me

Don't even get me started on ES2015 and ES6 being the same thing.

nimoson Ask HN: What are the best MOOCs you've taken?

CS50x and Stanford's Startup Engineering one.

Got me into programming and part of an exclusive club of MOOCs I've started AND finished.

nimoson Polymer breakthrough reveals unprecedented alternative to battery power storage

https://en.wikipedia.org/wiki/Lithium-ion_battery#Performanc...

Wikipedia shows 100-250whr/kg for lithium ion. Not familiar enough to know which is right.

nimoson Chip Aging Accelerates

Optimised acceleration/deceleration would probably save more fuel than self driving hardware uses, for city driving at least.

At 60mph you'll be using 10-20hp to maintain speed so about a 1-2% loss per 150W chip(well a bit more for conversion losses).

nimoson Announcing TypeScript 2.7

Ah nice thanks, must have missed that announcement. Do you know offhand if that works with a webpack toolchain using one of the ts loaders? Haven't been doing much web stuff lately and last version I've used was 2.5.

nimoson Announcing TypeScript 2.7

No incremental compiler? I thought that was coming in 2.7. Really hope that lands soon. Compile times are my only complaint about TS, otherwise it is so much nicer than writing JS for anything mildly complex.

nimoson Goodyear Hid Evidence of 'The Worst Tire in History' Linked to at Least 9 Deaths

Seems kind of crazy things can be sealed like this in cases regarding public safety.

nimoson Hetzner Cloud

Loving the competition in the market. Object Store would be nice. Can't wait to see what happens when NAND/DRAM markets start clearing and there are multiple competitive 7nm nodes.

nimoson Netflix is now worth more than $100B

Exactly how their current app works. You download from the app store then login to access the content. Each game is it's own app on the app store. Maybe it violates TOS but their current app and others like spotify use the same mechanic to restrict access.

nimoson One Bitcoin miner is buying 20,000 16nm wafers from TSMC per month

That's my point exactly. They sell them to other people to ensure that doesn't happen.

Now I'm not actually sure if they produce enough for that to be relevant. But my understanding is they dominate the asic market and asics are the only thing that are profitable for mining bitcoin. It could be if they didn't sell and mined themselves they would have enough mining share to cause people to lose faith in the currency and crash the market.

nimoson Netflix is now worth more than $100B

Sense8, The Get Down, Marco Polo. They are planning on spending 8 billion on content this year. Lets say they spend 10 million on a couple puzzle/king/angry bird style games. That's .125% of their content creation budget.