Cronopete – A Linux clone of Time Machine - <AUTHOR> https://rastersoft.com/programas/cronopete.html <comment><USER2> Ubuntu's backup thing (duplicity?) does something like this too. I can right- click in a directory and restore deleted files, or on a file and view previous versions.

One suggestion for the author of that webpage, and a common complaint I have with open source software websites in general: tell us what your software does. I haven't used a mac, I don't know what features time machine has in any sort of detail so telling me it's a clone is pretty useless. Give a one-or-two sentence saying what it does, and then some bullet points of key features.

There's more description of the name than there is of the functionality.

<comment><USER3> Duplicity works by making a full backup and then series of incremental backups based on it. Eventually you can make another full backup and new series, but you cannot delete full or incremental backup without rendering whole series corrupt. In Time Machine (and - I presume - this software), if you delete a backup checkpoint for a specific date you lose only file changes captured by that checkpoint, but state of the backup at the checkpoints before and after remain intact.

<comment><USER4> I believe the correct name for what time-machine does is differential backups.

Instead of doing a full backup and then having a chain of incremental backups, each differential backup stores all the differences from the full backup, so they are much larger but it allows you to delete previous differential backups.

</comment></comment></comment><comment><USER5> What i really miss on Linux, or for backups in general:

Make it super easy.

I just want to open the software and tell hey here is my network drive/external drive. Please start the backup of all my installed apps, all my configurations, all my music and develop files.

Also for restoring, just make it easy. Can somebody point me to a good solution? The problem is Linux is too diverse. Either you use basic tools like rsync which everybody can use, or you get super specific with automated btrfs backups onto a specific btrfs drive with deduplication and backup snapshots. Sounds super useful. But not easy as well. Also a gui would be nice, or at least a super in depth tutorial walking you through backing up your apps, your configs, your ssh keys. whatevs.

<comment><USER6> I've used restic ([https://github.com/restic/restic](https://github.com/restic/restic)) in the past, and it works quite well.

Other people would also recommend borg ([https://borgbackup.readthedocs.io/en/stable/](https://borgbackup.readthedocs.io/en/stable/)) although I've never used it so I can't say anything about it. rsync.net even has a special offer if you're using them ([https://www.rsync.net/products/borg.html](https://www.rsync.net/products/borg.html))

But really if you want to make it dead simple you can't go wrong with tarsnap ([https://www.tarsnap.com/](https://www.tarsnap.com/)). It's written and maintained by one of the biggest names in the crypto community, the guy who has spawned scrypt, among other things.

<comment><USER7> > But really if you want to make it dead simple you can't go wrong with > tarsnap

I'd call this everything but dead simple. Maybe for the average software engineer it's okay but I don't I could tell anyone in my family to set this up themselves and then monitor that it's doing it's thing correctly.

TimeMachine is two clicks in self explaining steps (Plug in empty external drive, OS asks if you want to use it as a backup source, you click "yes" and it starts doing backups every hour). That's probably what GP meant with "Make it super easy." not this: [https://www.tarsnap.com/gettingstarted.html](https://www.tarsnap.com/gettingstarted.html)

It's a cool service but it's not "dead simple".

</comment></comment></comment><comment><USER8> Can also recommend BackInTime, which is just a GUI for the rsync command-line app - like all good Unix utilities should be. Though BiT is Python 2 I believe, and I don't know if it did make it into Ubuntu 20 LTS yet (probably yes, and there's nothing to worry).

<comment><USER9> GH page says Py3.

<comment><USER10> Indeed they only test on Python3: [https://github.com/bit- team/backintime/blob/master/.travis.y...](https://github.com/bit- team/backintime/blob/master/.travis.yml#L14)

</comment></comment></comment><comment><USER11> Time Machine is one of the best features of macOS in my opinion. Apparently your mileage may vary, but I've never restored a backup to a new computer with such ease as I did when I swapped a MacBook Air for a MacBook Pro last year. I'll be saving this and giving it a try on my Linux boxes.

<comment><USER12> Time Machine has one huge issue: when it doesn't work, it becomes a bigger problem.

<comment><USER13> Could you elaborate on how Time Machine doesn't work? It's been pretty trouble free for me; other than taking a ridiculously long time for the initial backup with no good indication of progress.

<comment><USER14> Simple:

\- make a backup,

\- have your Mac serviced; it will be returned wiped,

\- try to restore from your backup - and it fails. It won't tell you why it failed, only that it failed.

The end.

<comment><USER13> OK. I have done that, several times [x], and didn't run into any problems.

I do wonder, though, what kind of integrity checks do Time Machine backups have. I've always treated TM as the first line of defence and, as such, it has worked well for me. However, in addition to TM, I have other offsite backups in the cloud for disaster recovery.

x) I haven't had my macs serviced several times, but I have restored from backups a handful of times due to, ahem, accidentally rendering the system unbootable a couple of times.

<comment><USER14> In my case, I did the TM backup specifically because my Mac was going to be serviced (display; so accessing data was not a problem).

Otherwise, I don't use TM, I'm using another solution. It won't restore entire system and installed apps, just my files.

So with TM, it was Murphy I guess.

<comment><USER15> This is actually how I have TM set up. I ignore anything not in ~/Documents (or any other location with personal files). The other stuff is so easily replaceable that I'm not concerned if I lose it.

</comment></comment></comment></comment></comment></comment></comment><comment><USER16> The distinguishing feature of Time Machine, and one which this project seeks to emulate, is its use of file navigation on the z axis.

Given the requirements of this particular task, this is the perfect choice. 3D navigation of the OS has been tried many times (Microsoft Bob anyone?), but to my mind, this is the only time it has really worked.

<comment><USER17> To me, the distinguishing feature of Time Machine is that it reliably works. It worked reliably when I first bought a Mac 12 years ago, it works reliably today. I'll put up with the fact that it's slow and naive (file and hardlink based), and the UI gimmicks are kind of unimportant to me. I care about the recovery.

<comment><USER18> I'm glad it works for you, but I abandoned it due to unreliability. My experience has been that it works fine for some period of time and then the sparsebundle will randomly break. MacOS claims it is corrupted, I have to jump through hoops to make it work again.

I will note that I'm doing it over a network mount, not a local drive, and this is probably the source of the problem, but I never could resolve it. So I'm just back to rsync for specific directories. Which is fine, when this Mac dies, I'm moving to Linux.

<comment><USER19> It was never real good about backing up over a network except with hardware specifically designed to support that, like network routers that support Time Machine drives (or Apple's own Time Capsule).

I don't know that I'd say my own experience with Time Machine is perfect, but it's generally done what I needed to do, and has actually saved my bacon a few times by letting me restore individual files back to specific versions easily -- something I'm not sure an rsync-based solution would really provide (e.g., versioning for everything).

</comment></comment></comment></comment><comment><USER20> The mechanism of rsync + hardlinks is similar to BackupPC[1][2], which is an 18 year old open source backup tool, written in Perl, with a web UI. It supports backing up Mac, Windows, and Unix-like OSs, and is primarily for centrally backing up multiple computers. BackupPC's UI is obviously not as slick as this, but it does allow restoring individual files from a given date. If I remember correctly from 10+ year ago, their tar over SSH transport option performed better than rsync when used on a fast network.

[1] [https://backuppc.github.io/backuppc/](https://backuppc.github.io/backuppc/)

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

<comment><USER21> For folks that want to back up data on remote servers, BackupPC is one of very few comprehensive backup systems I've found that can run on a server hidden in a closet somewhere and connect out to the remotes to retrieve data. Most backup systems run on the remotes and have the remotes connect into the backup server in some fashion, which I find kinda horrifying.

I've used BackupPC for a long time and I totally love it, though I get why it's never been the most popular option. The initial setup will take an experienced sysadmin a couple of hours if they're doing it for the first time.

<comment><USER22> This is pretty straightforward to do with standard rsync. You just setup a ssh tunnel first and have it use that. That's how I backup my VPS from my home fileserver.

</comment></comment></comment><comment><USER23> Why not use borg? With fusemount i can mount a snapshot and navigate/restore the files. It's very convenient.

<comment><USER24> Or Vorta, if you want GUI. [https://vorta.borgbase.com/](https://vorta.borgbase.com/)

<comment><USER25> They missed a real opportunity to name it "Locutus".

</comment></comment></comment><comment><USER26> Reminds me of Timeshift on Linux mint: [https://github.com/teejee2008/timeshift](https://github.com/teejee2008/timeshift)

Used this with joy for a few years now

<comment> j-james Not just for Mint, I've had a very good experience with it on Manjaro. Especially with a pacman hook to backup before a system update [1]...

[1] [https://aur.archlinux.org/packages/timeshift- autosnap/](https://aur.archlinux.org/packages/timeshift-autosnap/)

</comment></comment><comment><USER27> Although neither the webpage nor README explains how it works, I'm guessing it misses a vital Time Machine feature, which is FSLogger.

If you have lots of files, scanning your whole directory tree every hour is too resource intensive, especially on battery power.

<comment><USER28> It delegates all the actual file operations to rsync. In practice, it looks like it does multiple scans each hour - glob on all excluded folders, then running rsync with a big list of excludes for each configured folder.

There no clever modification monitoring. I'd keep this away from folders with many thousands of files.

<comment><USER29> I'm the author. I doesn't do a glob on the excluded folders, it just passes the list to rsync.

Also it changes the priority of rsync, to avoid it using too much CPU.

</comment></comment></comment><comment><USER30> I had initially thought that it was just a MacOS X app clone but however since trying it out I have found that it is actually better than the app was trying to replicate. I'm gonna port this to gentoo now, see you guys in ten years.

</comment><comment><USER31> Funny that the developers seem to be spanish speakers.

Crono = Chrono Pete = Blowjob

<comment><USER32> I'm a Spanish speaker and that does not make much sense to me, but it might mean something in the latin american variants, I guess.

<comment><USER33> Urbandictionary says it's Argentinian slang.

<comment><USER32> "Pete" seems to work as slang, and it kinda makes sense to me reading the UD explanation, I was just confused by the Chrono part in the original comment.

</comment></comment></comment></comment><comment><USER34> Found a typo. Change this:

> one dairy copy for the last 15 days

to this

> one dairy copy for the last 15 dairs

Also, what's the speed of choosing to delete one of the snapshots sandwiched in between other snapshots?

</comment><comment><USER35> Can someone explain to me why Time Machine is so great? I've used it, but I've just never found it worthwhile in comparison. For me it was very slow (but worked in the background which was nice), only mimiced my drive based off of whats currently on it and if I deleted it in the past.

I guess because I have several backups that I rotate, that essentially is my time machine that only goes as far back as my last backup for that drive.

<comment><USER36> I think the killer feature of time machine is that it's dead simple and intuitive for non technical users to do regular full system backups.

You plug in an external HD, open time machine, flip a big switch that goes from "Time Machine is Off" to "Time Machine is On" and the software does the rest.

Full backups, incremental backups, reminders to connect your drive when it hasn't been backed up for a while, and a visual interface for selecting previous versions to restore to.

<comment><USER35> My problem with it is that I still need another mac to use it. In the event of an emergency (IE theft or disaster), the last thing I want to hinder me from accessing my backup is an operating system. Especially a high cost and not as commonly used in public spaces operating system.

</comment></comment></comment><comment><USER37> Wonder when something similar appears named JohnTitor.

</comment><comment><USER38> Restic feels like a good alternative with a CLI. It supports lots of backends too, either directly or through rclone.

<comment><USER39> i've been using restic daily to a local store (with compression and encryption turned on), and then once restic has finished its daily run then i rclone to backblaze. i keep one snapshot per day for a week, 1 weekly snapshot for a month, and 6 monthly snapshots. i pay about £1 per month for about 250GB of data (prior to compression / encryption).

for those unfamiliar to restic, you can mount a r/o snapshot via fuse for ease of access as well as the command line tool to programmatically access the repo.

<comment><USER38> Why don't you let restic upload directly to backblaze? I am sure you know this is possible, just wondering on why you made that choice, not trying to be a smartass ;).

<comment><USER39> I did at first but the latency was a killer; it took about 2~3 hours to make a snapshot. If I did the snapshot locally and then used rclone to back up the restic repo to BB then the whole operation took about 15~20 minutes, and the snapshot itself took less than 5; if the rclone gets interrupted you can just restart it.

</comment></comment></comment></comment><comment><USER40> I'd be wary if a backup programm doesn't strongly distinguish between the logic (the command-line client) and the gui. I cannot tell if this one does, but since it tries to "mimic [Time Machine] as closely as possible", I guess it does not.

<comment><USER28> There's a dbus layer which defines the actual backup operations, so without actually diving into the code to confirm this - I suspect there's a reasonable separation.

</comment></comment><comment><USER41> Tangentially related -- Dragonfly's HAMMER(2) FS has historic fine-grained snapshots built-in as a first class citizen.

<comment><USER42> As does ZFS, unless I'm missing some distinction of "first class" in ZFS.

I'm really looking forward to Ubuntu 20.04 ZFS support. If I can use crypto with it (either the ZFS crypto or LUKS stuff), I'm going to switch my workstations over to it. ZFS snapshots work so, so well.

One thing I've really wanted from HAMMER is the deduplication. I've always had problems with ZFS dedup. I tend to really want it on my backup servers, but the DDT requires pretty amazing amounts of RAM. HAMMER's dedup seems less RAM- hungry, but I've only run small tests of it.

</comment></comment><comment><USER43> How does vala compare to other GUI focused languages?

</comment><comment> awinter-py on the market for self-hosted remote backup with partial checkout features & mobile client

am sort of using owncloud for this now but it's slow

</comment><comment><USER44> Er.. Rsnapshot?

<comment><USER45> Rsnapshot is great. Super simple and reliable.

I keep seeing new time machine-esque backup tools and feel like they are re- inventing the wheel in a more complicated way.

Some complexity is acceptable sure, say to encrypt backups for remote storage.

But the rsync hardlink approach used by rsnapshot is super rugged and just works for a majority of workloads.

</comment></comment><comment><USER46> pete in some south american countries means "blowjob".. i know its a bit niche but i cant help to giggle when reading this product name.</comment>


Learning about Redis through writing a Twitter clone - <AUTHOR> http://danlucraft.com/blog/2009/05/learning-about-redis-through-writing-a-twitter-clone/

<comment><USER2> demo at <http://retwisrb.danlucraft.com/> gives error 500 currently.

<comment><USER3> Fixed</comment></comment>


BBC website (no longer) returning a JSON weather forecast by mistake, sometimes - <AUTHOR> https://www.bbc.co.uk/ <comment><AUTHOR> Looks like they fixed it. It was returning:

        {"forecasts":{"day1":{"dayNameAbbreviation":"Tue","day":    {"weatherType":"Sunny","weatherCode":1,"maxTemperature":31},"night":{"weatherType":"Thundery Showers","weatherCode":28,"minTemperature":17}},"day2":{"dayNameAbbreviation":"Wed","day":    {"weatherType":"Sunny","weatherCode":1,"maxTemperature":29},"night":{"weatherType":"Clear Sky","weatherCode":0,"minTemperature":15}},"day3":{"dayNameAbbreviation":"Thu","day":{"weatherType":"Sunny","weatherCode":1,"maxTemperature":34},"night":{"weatherType":"Partly Cloudy","weatherCode":2,"minTemperature":17}}},"location":{"id":"rh16","locationName":"RH16"}}

It seemed to be load balancing my requests, sometimes I got JSON and sometimes the expected web page.</comment>


UK sees longest period of negative power prices - <AUTHOR> http://www.argusmedia.com/news/article/?id=1474697 <comment><USER2> I'd recommend the book _The Grid_ as a primer on how stuff like this can happen. Energy is strange, in the sense that everything produced needs to be used more or less immediately. Maintaining the energy grid is a careful balancing act between preventing surges and blackouts.

There are a lot of grid-related engineering problems that come from increasing decentralization (e.g. wind, solar, hydro) because it increases unpredictability in supply.

[https://www.amazon.com/Grid-Fraying-Between-Americans- Energy...](https://www.amazon.com/Grid-Fraying-Between-Americans- Energy/dp/1608196100)

<comment><USER3> Bought the book, but spoil a little for me if you would: I know that some utilities turn on pumped hydro storage to handle excess capacity, but what other ways are there to efficiently waste energy?

<comment><USER4> Flywheel storage for wind energy. It's mostly used for grid balancing.

Beacon Power has a complete solution but they went bankrupt in 2012, then got bought by Rockland Capital who intend to rehire the staff and build a 20 MW plant in Pensylvania.

Also, here's an article of such an energy storage project in Ireland by Schwungrad Energie Ltd.

[https://www.rte.ie/news/business/2015/0326/689945-renewable-...](https://www.rte.ie/news/business/2015/0326/689945-renewable- energy-storage/)

<comment><USER5> Right now and for the foreseeable future, lithium ion batteries are a better alternative to flywheels, though they will see some use for applications that require high power but little total stores energy.

The power:energy ratio is high, but has few applications on the grid. Even lithium ion's typical 4:1 MW:MWh is a bit high.

The really unexplored territory is seasonal storage. Electricity to hydrogen, methanol, etc. have huge round trip efficiency hits, like 30%-50%, but may make a ton of sense.

</comment></comment></comment></comment><comment><USER6> Ah finally something I am knowledgeable about.. building a software simulation system for a smart power-grid that can account for renewable energy sources was my grad school research project. Linked here if you wanna learn more: [http://arunpn.com/projects/aces-co- simulator/](http://arunpn.com/projects/aces-co-simulator/)

<comment><USER7> Someday, there will be a topic on HN about which I too am knowledgeable... someday.

</comment></comment><comment><USER8> Perhaps I'm not fully understanding how this works, but could one conceivably run a business whose only product is predicting when the price will go negative and "wasting" power?

<comment><USER9> Perhaps not just when prices are negative, but it's not an uncommon practice to 'store' power by pumping water uphill when it's cheap and demand is low (generally at night), and then using that potential energy to generate and sell it when electricity is more expensive.

I have absolutely no clue what it would take to make that profitable, but it's a strategy for handling the natural spikes of demand when using power generation methods like solar and wind that are unable to adjust quickly to changing demand.

<comment><USER10> >I have absolutely no clue what it would take to make that profitable

You need a large watershed with a wide range of useable head. It is an excellent system when the geography and hydrology allows for it.

Unfortunately, such areas are not common or evenly spread, and are not really possible to economically construct without a great deal of cooperation from the local geology.

<comment><USER11> You also need one where you're given significant environmental carte blanche. These types of projects are similar to dam projects in the scope and scale of the amount of the environment that they destroy, times two as you need upper/lower ponds.

<comment><USER12> Your lower pond could be the sea.

<comment><USER13> So then you're pumping salt water into (presumably) a fresh water lake. I don't think that decreases the environmental damage.

<comment><USER12> Yep, your upstream lake should also be saltwater.

<comment><USER14> As the sibling comment shows, you can build an artificial lake large enough to be feasible. The Okinawa plant seems to have been decommissioned for lack of need (at its given cost). It was probably a victim of the current oil/gas extraction boom and artificially deflated oil prices. Still, I wonder about their ability to control costs due to corrosion--salt water is horrible for this reason.

<comment><USER10> I couldn't find much more about the site in English, but considering how expensive the lining must have been for what was a pretty small storage pool, in addition to needing expensive materials like stainless steel and assorted specialty plastics to deal with corrosion...

I can't know for sure, but regardless of whether they say it was due to weak demand or not, I bet it was the saltwater issue that sunk the project more than anything else.

</comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER15> And it has been so sunny in California that electricity prices have turned negative (late morning, temperate spring weather with low load, high hydro output due to a wet spring)

<comment><USER15> And you can watch at home: [http://www.caiso.com/pages/pricemaps.aspx](http://www.caiso.com/pages/pricemaps.aspx)

<comment><USER14> The Internet and open data movement are just incredible. I am still amazed that regular people can get such insight, and fairly well presented anytime online.

</comment></comment></comment><comment><USER16> > for five consecutive hours ... as the grid was oversupplied owing to high > wind generation during off-peak hours of low demand.

This is exactly the problem the detractors have with grid connected wind and solar.

<comment><USER17> I have two qualms about this claim: The first is purely economical. Does this not simply indicate that there is insufficient supply of electricity _storage_ (ie batteries)?

The second is... wow, if excess supply of energy is a reason there are detractors to wind and solar, then maybe treating electricity as a market is totally misaligned with perpetuating sustainable human activity. Maybe we shouldn't do that.

<comment><USER18> The oversupply of electricity is not the cause of "detracing" solar and wind. It's its undersupply on a winless overcast evening.

What we need is cheap (per GJ stored) longer-term electricity storage.

<comment><USER19> Tesla Gigafactory to the rescue!

</comment></comment></comment></comment><comment><USER20> This just means inefficient pricing. If prices were adjusted in real time, one could schedule charging car batteries, heating water in the electric water heater, etc., when prices are cheap.

<comment><USER21> Inefficient usage, not pricing

<comment><USER20> Usage patterns follow pricing.

<comment><USER22> If only that were true for electricity. Nobody needs it at night, despite it being cheap then.

<comment><USER20> People charge their electric cars overnight. Water in the hot water tank will stay hot for a couple days, so it makes sense to heat that at night, too.

In hot weather, you can also run the energy-hungry A/C at night to cool a tank of water or a block of masonry, then use that during the day to cool the house.

The reason nobody bothers doing that is because the price of electricity is the same day and night.

<comment><USER23> Wouldn't the inefficiencies of doing that outweigh the cost benefits? Or is night time power so much cheaper that it'd be worth it?

<comment><USER20> Why would it be inefficient to charge your car battery at night? And storing coolness in a masonry slab doesn't sound inefficient to me. Pumping water uphill and running it back through a turbine is pretty inefficient.

<comment><USER23> I was referring to the cooling part, not the car charging. My totally unsubstantiated gut feeling is that a piece of concrete or a tank of water wouldn't stay cold long enough to be useful. With my local company, electricity during the day is something like 20%-100% more expensive (less of a differential in winter, more in the summer)

<comment><USER20> Masonry as thermal mass in homes has been in common use for centuries, maybe even millennia:

[http://www.greenbuildingadvisor.com/blogs/dept/musings/all-a...](http://www.greenbuildingadvisor.com/blogs/dept/musings/all- about-thermal-mass)

</comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER24> These problems are fundamentally about the loss of what's called "spinning reserve".

In a traditional steam turbine generator system, a number of generators are run at well below fully capacity with a full head of steam in the boiler but essentially ticking over.

When there is a sudden requirement for extra power signalled by a relatively small drop in voltage, the inertia in the spinning turbine and alternator take up the load as the governer opens the steam valve releasing as much of the stored pressurised heated steam in the boiler to take up the load, as it is the reduction of temperature of the steam that is the primary source of power.

The loss of so many steam turbine powered systems is causing the problem.

If these issues are to be solved it is about insufficient energy storage systems such as inertial storage systems or batteries to take up the function of spinning reserve.

<comment><USER25> Demand for extra power manifests as a drop in frequency not voltage.

<comment><USER24> Its both in Australia as strange as it may seem.

In certain parts of Australia Frequency is deliberately maintained throughout a wide range of load demands which means it is by other means (magnetic amplifiers) that voltage is used as the signal for power.

It is not until voltage signally cannot maintain the desired frequency that the under frequency load shedding kicks in.

In fact the obsession with frequency is so high that over time beyond any 24 hour period (and thus even years) that an electric synchronous clock is usually always within at most a few 100th of a second out, as the system frequency is adjusted up and down to correct for accumulated errors.

As a result frequency control is spot on but voltage control is generally pretty awful.

<comment><USER25> Use of load shedding or generation shedding to balance load and generation on a grid are a different mechanism than the continuous adjustment of generator output by the governor in response to changes in frequency that occur as mismatches in real power demand and generation result in changes in the kinetic energy of every synchronous machine.

Load shedding is triggered by underfrequency and undervoltage elements, generation shedding is triggered by over frequency elements.

I am aware that in New Zealand the distribution utilities (especially in Christchurch) perform 'peak shaving' to reduce the peak demand on some substations by turning off people's hot water tanks using a ripple signal injected on to the power system, but that is to alter the load profile not perform frequency regulation.

Every large system operator attempts to balance the positive and negative frequency errors from 60Hz to zero over a 24 hour period so that clocks are correct, that is not unique to Australia.

Can you provide any links to how voltage is used to regulate the frequency in certain parts of Australia? A magnetic amplifier is not a term I am immediately familiar with. It almost seems to me like a normal synchronous generator, where a current in the rotor causes a rotating magnetic field, which then induces a voltage in the stator that is much large (magnetic amplifier).

I am an EE and program power plants including turbine governors that regulate the system frequency so I am curious about any methods that differ from what we are doing in North America.

<comment><USER24> The Magnetic Amplifier is between the pilot exciter (a permanent magnet generator) and the main exciter and sends a "feed forward" to the pilot oil governer so it reacts before the speed of the turbo alternator slows.

</comment></comment></comment></comment></comment><comment><USER26> Found a good summary of imbalance cash-out prices: [https://www.elexon.co.uk/wp- content/uploads/2016/10/Imbalanc...](https://www.elexon.co.uk/wp- content/uploads/2016/10/Imbalance_Pricing_guidance_v11.0.pdf)

The basics seems simple enough - the system was long (too much supply) during this period above and beyond what is contractually ordered between generators and electricity suppliers (eg, to consumers).

Having a negative price would seem to make sense if your goal is to keep consumption balanced with generation on an open market.

</comment><comment><USER27> Does that also mean that the producers of the excess energy are charged for supplying power due to the negative price?

<comment><USER28> Theoretically yes, though I guess the details are a little more complicated (depending on who exactly bought the energy and under what terms). e.g. energy company x might have bought all the capacity from wind farm y for the next 10 years, so then the fact that it's producing excess energy at that point in time becomes x's problem rather than y's. Presumably x would factor stuff like this in to their purchasing decision, so as long as the average price remains above some level they will still make a profit.

</comment></comment><comment><USER29> Bitcoin mining will be super profitable then!

<comment><USER30> Or bitcoins will simply be devalued, and lose buying power until electrical demand changes or all of the last possible bitcoins are finally mined into existence.

</comment></comment><comment><USER31> So if you operate a windmill in your backyard while prices are negative the power company will send you a bill? Why couldn't the power company just break the circuit if they couldn't handle the incoming power? The windmill would still spin but not generate any power, like a gas generator with nothing plugged in. Seems better than sending the windmill operator a bill so the power company can generate a bunch of steam 100s of miles away...

<comment><USER32> Sigh. This gets posted so many times.

There are no negative prices.

Here's how it works: Generators put out bids for how much they can produce and the price. Consumers pull in the bids ordered by price until they have enough power.

After that they pay everyone the _highest_ price for the power.

So making your power negative just means you want to be first on the list.

You don't actually get paid negative money. It's just a tactic.

<comment><USER25> If demand is low then the highest price can be negative.

When prices are negative Generators have to pay for the power they produced, for the privilege of not shutting down their process be it nuclear, coal etc. presumably hydro and natural gas would shut down in response to negative prices.

<comment><USER32> This doesn't happen. If you shut down every fast responding power source, then there is not enough power and the price will not go negative.

For example the article talks about wind. Wind generators have no problem shutting down.

No, it's not about the privilege of not shutting down, it's what I said: it's simply the bottom of the order book, not the actual flow of money.

<comment><USER25> The article is about this just happening in the UK. For 5 consecutive hours the price was minus $25.

It also happens in Ontario, and maybe elsewhere but I don't know as much about how other markets deal with oversupply.

Wind generators generally have fixed price contracts for as much as they can produce so they carry on generating even if the price is negative and they get the same positive price. Or if they do have to shut down for system reliability they will get paid even though they didn't generate any power. That is called being constrained off.

If the price is negative it is because generators would rather pay than go offline. The nuclear plants in Ontario will bid negative because they have real costs if they have to alter their output.

I maintain that the price is negative because the highest selected bid was negative, and any generators producing during those 5 hours had to pay $25 for every MWH they produced.

are you in the power business in the UK?

I used to work on software that implemented the market settlement rules in Ontario in order to calculate a distribution utility's cost of power every day, and I've also spoken at length with an economist who wrote market rules, and examined the behavior of the market participants for compliance with the rules, but it is possible that the uk and Ontario markets differ in this regard, although the article indicates the price was negative.

</comment></comment></comment></comment></comment><comment><USER33> Negative LMP prices happen all the time in the US in regions with heavy wind. This isn't unusual.

</comment><comment><USER34> "Find me a giant resistor!"

I'm sure this is probably like gas pipelines in that a swing producer can get an advantageous contract if they agree to take or make power as needed.

</comment><comment><USER35> I don't understand how negative power prices can exist? Why wouldn't everyone just dump the power into the ground and make a profit? Surely 0 has to be a floor.

<comment><USER28> You could think of the problem in reverse: there's an excess of energy and they need to pay people to get rid of it (because using that much energy isn't as easy as dumping it in the ground).

If you could find a good way of getting rid of a lot of excess energy (worlds biggest kettle?) then you could potentially make a bit of a profit! Until someone comes along and finds something useful to do with the energy...

</comment></comment><comment><USER36> Tell this to EDF, they recently sent a letter warning of a price increase and gave an example where if you have £1000 bill it will go up to £1200

</comment><comment><USER37> So can I get cash back by cranking up my heating next time it happens?

</comment><comment><USER38> If only there were some way to store energy for future use.</comment>


This 26-Year-Old Is Making Millions Cutting Out Traditional Publishers - <AUTHOR> http://www.businessinsider.com/amanda-hocking-2011-2 <comment><USER2> That $1 is all she would have made per book selling the old way anyway.

<comment><USER3> Yes but assuming perfectly elastic demand, being able to sell the book for $1-$3 instead of $10-$20 à la "the old way" means that she'll sell a great many more, collecting the $1 on each one. More books, more dollars. Win.

<comment><USER2> I was agreeing with your point not going against it.</comment></comment></comment>


How I made $1000 exploiting a broken market (2008) - <AUTHOR> http://jessepollak.me/2012/06/14/how-i-made-1000-exploiting-a-broken-market/

<comment><USER2> Interesting article, and I think it brings up a really good point. There must be tons of opportunities like this that we just don't know about.

Why did you stop at only $1000?</comment>


Ask HN: have you built an electromagnetic levitator? - <AUTHOR>

Theoretically, what's the biggest gap you could create between the levitator and the object?  Why is it that all examples of levitation I've seen on youtube lift an object just an inch or two?
The specific challenge is to suspend a Canadian penny from the ceiling; it's primarily steel, and strongly influenced by magnets.  My current strategy is to:
- use an arduino for the controller
- drive an electromagnet with a sinusoidally modulated voltage
- use a hall effect sensor to detect the distance of the penny
- in the arduino, change the maximum voltage of the electromagnet, based on the voltage coming from the hall effect sensor
I don't know how the penny will behave when it's in the field, so I don't know if the hall effect sensor will be able to detect the penny's distance.  Obviously, when the penny isn't magnetized, it will be invisible to the sensor, but I hope it will behave differently when it's actively being levitated.
I am not sure why this system will become less stable as the distance from the electromagnet increases, but it seems like it must.  It also seems like the amplitude of the sine wave is going to need to increase, based on the distance from the penny, to cause grosser adjustments to the penny.  I'm assuming that because in the opposite case, when the penny is close to the electromagnet, it seems like you will only need to make small adjustments to keep the penny a specific distance.  I assume the relationship between distance and the amplitude of the sine wave will be non-linear, which will determine the maximum distance the penny could ever be.
Here is a specific question: how do I determine the force of attraction between the penny and the electromagnet given the distance and the voltage of the magnet?
This is still in the earliest stages, so any advice at all will be appreciated! <comment><USER2> The reason they only lift an object only an inch or two (and usually less) is that magnetic field strength falls of to the cube of the distance.

I think you'll be learing a lot about servo systems, search for PID control loops.

And good luck, that's a tricky thing you're trying to do there.

Be sure to post it if you got it working!

<comment><AUTHOR> Thanks jacquesm!

The more I look into the problem, the more challenges I'm finding. A friend of mine did this for his master's thesis back in 2002, so I know it's not impossible, but he had a strong background in EE (whereas I'm a relative n00b).

Also, thanks for the search query. I'm checking on it now.

<comment><USER3> It's almost a perfect storm of inconvenient equations. Magnetic field strength drops off as the cube of the distance, so you want to increase the current in the coil, but power loss (and thus heating) in the coil goes up as the square of the current, while field strength is only linear.

</comment></comment></comment><comment><USER4> Assuming the penny is ferromagnetic you might be able to use DC to drive the electromagnet (i.e. you don't need to excite a current in the penny to get it to be attracted to the magnet).

Also, the magnetic field is going to be proportional to current, not voltage (and because electromagnets are highly inductive, you can't assume the two will be linearly proportional).

In fact you might be able to use the current rise in response to a voltage pulse as a measure of the inductance of the magnet/penny system and use that to measure the distance.

The old levitating spheres that The Sharper Image sold used an optical system (IR LED and photodiode) to detect the position of the sphere and modulate the magnet (arranged horizontally just above where the sphere would hang), but that might not be as impressive as having it hang out in space.

Sounds like a tricky problem :)

<comment><AUTHOR> Thanks for correcting the voltage/current error - you're totally right about that.

Great idea about the voltage pulse! Let me see if I have this right: with a known voltage, the current will rise in proportion to the nearness of the penny? That is, for a fixed voltage, when the penny is closer, the current will be higher?

</comment></comment><comment><USER5> Or you could use a high temperature semiconductor. True, there are cooling issues you'd have to overcome but the thing about levitating using a semiconductor is it is self-stabilizing.</comment>


Firefox drops Google as default search engine, signs five-year deal with Yahoo - <AUTHOR> http://www.theverge.com/2014/11/19/7250513/firefox-signs-yahoo-as-default-search-engine-/ <comment><USER2> Wow, just wow. I don't know the last time I searched using Yahoo.</comment>


macOS Catalina Will Replace Bash with Zsh ― Scotch.io - <AUTHOR> https://scotch.io/bar-talk/macos-catalina-will-replace-bash-with-zsh <comment><USER2> "Replace" is a loaded word, this is blogspam. In Catalina the default login shell for new users will be Zsh, but Bash will still be on the system (and likely still the default shell for upgraded users). So in practice, if your bangs are correct and you upgrade your systems, nothing will change.

<comment><USER3> In the developer beta, existing users are moved to zsh on install.

</comment></comment><comment><USER4> I'm not even complaining about the ads. Where's the content?

 _Apple is recommending developers switch out bash to zsh in anticipation of this change._

That's it? Not even a 'Here's a Bash to ZSH migration' tutorial or anything?

</comment><comment><USER5> "Apple replaces shell designed 30 years ago with one designed 29 years ago"

FISH, the "Friendly Interactive Shell"\-- now 15 years old-- provides a more substantial leap forward in autocompletion and auto-suggestion, while adding some breaking changes to improve the overall design of the language and user experience. It's still highly compatible with bash or zsh syntax for day-to- day usage.

[http://fishshell.com/](http://fishshell.com/)

Try `fish_config` to launch a browser where you can select a theme. Enjoy autocompletion for 500 commands by default. Need help for a built-in command? Try `help test` to read the docs for the `test` command in your browser.

<comment><USER6> Oh my zsh and a few zsh plugings completely blow fish out of the water for me. First off zsh doesn't have any supposed syntax improvements so I can take any new skills I acquire to environments other than my own.

<comment><USER7> I think array indexes start at 1 in zsh rather than 0 as they do in bash. It sounds like such a ludicrous change that I'm having trouble recalling if this is really true, but I had previously used zsh a lot... Just got lazy with my last MBP upgrade and never installed zsh.

</comment></comment></comment><comment><USER8> Previous discussions:

[https://news.ycombinator.com/item?id=20090193](https://news.ycombinator.com/item?id=20090193)

[https://news.ycombinator.com/item?id=20102427](https://news.ycombinator.com/item?id=20102427)

</comment><comment><USER9> I use the terminal on a daily basis, but not too much with shell scripts anymore. Will I notice a difference?

<comment><USER10> Most shell scripts start with a reference to the program that should execute them at the top of the file (i.e. #!/usr/bin/bash), so this shouldn't affect most people, especially since this change will only apply to new users.

<comment><USER9> I missed that "new user accounts" the first time I read it.</comment></comment></comment>


Changing San Francisco Is Foreseen as a Haven for Wealthy and Childless (1981) - <AUTHOR> https://www.nytimes.com/1981/06/09/us/changing-san-francisco-is-foreseen-as-a-haven-for-wealthy-and-childless.html <comment><USER2> The solution is the same as every other time this comes up. Upzone the city. They tried this at the state level with SB827. That bill was flawed but the idea was good.

The city could fix this for itself if they could get the political will to do so. Follow the lead of Minneapolis, and make R1 zoning good for up to four units, instead of single family. That one change alone would make a huge difference.

People are afraid whole city blocks would be converted, but that wouldn't happen. Single family homes with good transit would slowly be sold to developers who would replace them with quads, bringing in increased taxes so that transit could be expanded, leading to more SFHs near transit, and so on.

It's just that the people who have SFHs don't want to ruin the "character" of their neighborhood.

<comment><USER3> I am curious - how old were the houses that were getting demolished in Minneapolis?

A lot of the houses that would be torn down SF are nearing 100 years old. That probably sounds comically young to people from Europe, but SF's neighborhoods are among the oldest west of the Mississippi.

You put "character" in quotes... but how far would you go with this? Would you support the right of a property owner to tear down an old building in the French Quarter of New Orleans and replace it with a modern steel and glass structure? How about an old building in the left bank of Paris?

The complicated thing about NIMBYism is that not all backyards are alike.

I say this with full acknowledgement that SF's housing policy has created a horrendous situation. But I actually do think it's possible to build substantially more density here, close to public transportation, without tearing down the older neighborhoods.

<comment><USER4> I've lived in San Francisco for 5 years now, and one thing I find ridiculous about this city is how ancient most of the residential buildings are. I'm currently living in an apartment that was built in the 60's, and have been to open houses of single family homes originally built in the 40's. Nowhere else I have ever lived would people be proud of that fact. In Atlanta and Vegas and Seattle I was able to find nice modern apartments to live in that weren't thin-walled, ancient plumbing, creaky floor wooden buildings well past their expiration date. But in San Francisco somehow people get offended when I suggest that an old building would be better torn down and rebuilt. (And yes there are some modern condos/apartments in SF but they are all in the range of $4000/m for a one bedroom and mostly clustered in the Dogpatch or SOMA which isn't a great area to actually live in my experience)

To answer the parent's question, I absolutely would support the right of a property owner to tear down an old building in the French Quarter of New Orleans and replace it with a modern steel and glass structure. Likewise with an old building in the left bank of Paris. I'd even like to incentivise that with tax breaks or whatever other levers are available.

<comment><USER5> I've lived in SoMA. Great place to live. Best weather in the city. Easy access to the waterfront, ballpark, Bart, Muni, and CalTrain.

edit: forgot bart

</comment></comment></comment></comment><comment><USER6> San Francisco described in a 1930s era book about the Gold Rush:

"Despite the amazingly high cost of living and the extraordinary opportunities for frittering away money, everyone in early San Francisco was supremely confident that he would soon be able to return home with an incalculable amount of gold. Everything was conceived on a vast scale, and there was always plenty of cash available for any scheme that might be proposed, no matter how impossible or bizarre it seemed. No one hesitated to borrow money, ..."

<comment><USER7> Wow. This could still be said today. I wonder what it is about that city.

<comment><USER8> It's beautiful in a perfect location with perfect climate. San Francisco will always be a desirable place to live.

<comment><USER9> The South Bay is probably closer to a "perfect climate" than SF itself which, after all, inspired the Mark Twain quote "The coldest winter I ever spent was a summer in San Francisco." That said, the overall Bay area climate doubtless contributes to the desire of many to live there to a degree that probably wouldn't exist if the equivalent job market were in Minneapolis.

<comment><USER10> SF over South Bay weather any day, especially summer.

<comment><USER9> It does depend. I actually like SF weather a lot but have also been unexpectedly frozen there from time to time. And don't like hot weather either.

</comment></comment></comment></comment></comment></comment><comment><USER11> This wsj article suggests that Tokyo, a much larger city, has been able to keep housing costs flat by building a much larger supply than most other city: [https://www.wsj.com/articles/what-housing-crisis-in-japan- ho...](https://www.wsj.com/articles/what-housing-crisis-in-japan-home-prices- stay-flat-11554210002)

This could work in SF I think, as there's a lot of potential for up-zoning. On the other hand, the city is surrounded by water, so it doesn't leave a lot of space to expand.

<comment><USER12> There are vast tracts of vacant land in SF, and the whole western half of the penninsula is low-density housing.

What Tokyo has that the Bay Area lacks is excellent public transit, and a willingness to build at high density.

<comment><USER13> Tokyo also merged with its Prefecture in 1943.

If only the Bay Area cities would amalgamate and solve housing and public transit as a unified force....

</comment></comment></comment><comment><USER14> For the curious, 2017: [https://news.ycombinator.com/item?id=13464747](https://news.ycombinator.com/item?id=13464747)

2015: [https://news.ycombinator.com/item?id=10070103](https://news.ycombinator.com/item?id=10070103)

</comment><comment><USER15> SF will never be a place people will want to have children. Americans do not believe children can grow up in cities. They do not believe kids can take buses or trains. We're going to see the effect of this suffocating parenting style in a next generation that is dominated by fear and discomfort with unfamiliarity.

<comment><USER16> But SF has its own issues beyond those of many other American cities.

There are blocks and muni buses where many adults feel understandably uncomfortable with what they see during their normal commute. I see drug use and nudity and feces on the street almost daily. I've kicked needles while walking down SF sidewalks with some regularity. I'm not a parent, but in those conditions, I wouldn't want a kid I cared about to go around unchaperoned.

Yes, America may have a fixation on children needing yards and minivans, but SF could become a much more appealing place to raise kids if it we could better address factors like the cost of housing, or the opioid crisis.

<comment><USER15> > _But SF has its own issues beyond those of many other American cities._

I agree with this.

But this

> _Yes, America may have a fixation on children needing yards and minivans_

means that fixing those problems won't make this any likelier

> _SF could become a much more appealing place to raise kids if it we could > better address factors like the cost of housing, or the opioid crisis_

</comment></comment></comment><comment><USER17> Of course, the Bay Area in general is comparable to other American metropolitan areas in terms of its number of children.

[https://www.kqed.org/news/11735556/map-where-do-kids-live- in...](https://www.kqed.org/news/11735556/map-where-do-kids-live-in-the-bay- area)

</comment><comment><USER18> San Francisco: on the verge of pricing everybody out since 1850</comment>


Pomodoro Technique – The Productivity Technique You've Been Missing - <AUTHOR> https://medium.com/@bwigginton/the-productivity-technique-you-ve-been-missing-2ce5728ddd6d

<comment><AUTHOR> OP here. I've been using Pomodoro for the last few weeks and wanted to share my findings with everyone.

I'm trying to work on my writing skills this year and would love to hear any feedback on the article.</comment>


Python NLP tutorial: Using NLTK for natural language processing - <AUTHOR> https://blog.hyperiondev.com/index.php/2018/01/15/nlp-tutorial-python-natural-language-processing/ <comment><USER2> Weak. This shows some statistics (easy) but nothing about how to build an NLP system that actually does something.</comment>


FactoryGirl has been renamed to FactoryBot - <AUTHOR> https://github.com/thoughtbot/factory_bot <comment><USER2> My reaction to this is basically "nothing to see here".

Libraries get renamed all the time. Whether the authors thought it was problematic or not, they decided to rename it so that there's no question. Who cares?

</comment><comment> ainar-g [https://github.com/thoughtbot/factory_bot/issues/921](https://github.com/thoughtbot/factory_bot/issues/921) \- Here is the original issue. And yes, it's about sexism, even though the name was a reference to a factory pattern and a song.

[https://github.com/thoughtbot/factory_bot/issues/921#issueco...](https://github.com/thoughtbot/factory_bot/issues/921#issuecomment-243173849) \- here is a comment I would like to highlight.

>There is real, honest, awful sexism in tech, but this is not it.

</comment><comment><USER3> Laudable action. Among all the noise about "political correctness gone mad" it's encouraging when small actions like these are taken.</comment>


Instant Web Application - <AUTHOR> https://glebbahmutov.com/blog/instant-web-application/ <comment><USER2> The blog post author (Gleb Bahmutov) here.

Thanks for commenting, this is a cool experiment I worked on, just trying to eliminate the bootstrapping delay. Will be happy to answer any questions here, via issues in the demo repos ([https://github.com/bahmutov/instant-vdom- todo](https://github.com/bahmutov/instant-vdom-todo)), or in the library repo [https://github.com/bahmutov/bottle- service](https://github.com/bahmutov/bottle-service)

The demo itself runs from [https://instant- todo.herokuapp.com/](https://instant-todo.herokuapp.com/) (please use Chrome or Opera or enable ServiceWorker in the Firefox for now)

PS: Here is a little bonus, my current exploration where ServiceWorker might be useful - run your server (like ExpressJS) inside the ServiceWorker ;) [https://github.com/bahmutov/express- service](https://github.com/bahmutov/express-service)

</comment><comment><USER3> Compare how over engineered this "instant web application" is with this todo written in turbolinks [http://todomvc- turbolinks.herokuapp.com/](http://todomvc-turbolinks.herokuapp.com/)

Basically just re render the app after each change. Works pretty well and no need to setup pre rendering flux capacitor dual node virtual dom isomorphic gulp flow.

<comment><USER4> Turbolinks does not solve any of the problems that client-side frameworks do, it's still just server-side rendering with enhanced performance. If you can build your app with it, great, but these are different animals.

<comment><USER3> Not really. I've done pretty well in my current app with Turbolinks partial replacements. You can do more fine grain changes such as appends. You can tell Turbolinks which part of the page you want to update. So if you have a counter in the nav and a counter in the footer, when someone clicks a button your response can update those other sections as well.

We've never had anybody complain about speed. If you can return responses in 100-300ms your good to go.

I do know it's limitations and that's keeping a lot of state in the client. In that case I'll usually fall back to rivets or vuejs. Yes I said fall back. People tend to go to a JS framework as the first solution. In my experience that's usually not a good idea. You'd be surprised how little you need a JS library, with a solution like Turbolinks

<comment><USER4> > I do know it's limitations and that's keeping a lot of state in the client. > In that case I'll usually fall back to rivets or vuejs

Exactly. We have always been able to do ajax loading even before Turbolinks. Client-side applications are a whole different matter, they have a level of interactiveness that is way beyond what's possible by sticking to server-side rendering. This is not a pissing contest, I just think your comment missed the point.

<comment><USER3> Funny thing is, I haven't had a single customer asking for platform agnostic backend services. I'll make sure I ask them about that though.

I can do all those things pretty easily with partial replacement. By a lot of state I mean things like highly interactive forms. This is where I've typically used Knockout or Angular in the past.

From what I see, developers these days use javascript frameworks for ridiculous things, and it's out of hand. I haven't been to a single website that uses React, Angular or EmberJS that actually needs it.

From what I can tell the background of React is, Facebook couldn't create a notification indicator on Facebook.com, so they create this over engineered dump pile to solve that problem. Now they can tell you how many unread posts you have while downloading 15 terabytes of Javascript.

Sprint.ly wrote a kanban board in React. As a customer I didn't care, there service already worked fine. Seems they've abandoned it at this point though. Probably couldn't take the React churn, or all the engineers have jumped to the next latest framework.

Don't get me started on Discourse. Netflix.com, viewing some movies and ratings? Been to several article sites that use React. For what? Yahoo.com re wrote mail client in React. Guess what no one cared. It worked fine when they owned Zimbra.

Catch my drift?

<comment><USER5> It's primarily a speed-of-light issue. If the server is on the New Jersey and I'm in London, it takes a perceptible amount of time for the signal to travel between continents.

The only way to remove this latency is for the client to take full responsibility for building the UI, instead of playing a complicated game of ping pong across the Earth.

While I don't particularly like React, that's what they're aiming for.

<comment><USER3> The funny thing is, a lot of websites I visit that use client side frameworks don't make optimistic/eager updates to the UI. You click a button, it hits the server does the update, then updates the button state. Therefore they're waiting for the roundtrip to the server before making the update anyway.

Just because something is possible doesn't mean people are actually using it. To make some optimistic updates you have to duplicate logic on client and server. It just gets really hairy especially when you're using auto increment id's in your database. That's just one of the problems. The complications it creates isn't even worth it. I'd rather just put a server in London. A lot less hassle then dealing with this over engineered client side bullshit.

<comment><USER6> > A lot less hassle then dealing with this over engineered client side > bullshit.

I like to deal with client-side apps which talk to a simple JSON API. It's a lot less hassle than dealing with this over engineered server side bullshit.

<comment><USER3> JSF with Java EE. That was over engineered.

This Redux flux capicator, isomorphic, 4 Terabyte NPM install, 45 Babel plugin, flow, dumb component pure functional, immutable js, virtual dom. Now that's over engineered.

I built more complicated stuff with Knockout.js in 2011 then half the stuff I see people building with React(which from what I see is just news sites and forum software)

</comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER7> Yes, that is a nice solution to the _users randomly pressing reload_ problem, if you consider that one.

For everyone else, there is server side rendering.

<comment><USER8> It's not only for people hitting reload, it's also for people visiting the app more than once such as slack, gmail, facebook or inbox. Pretty cool. It doesn't solve the first load though that's ok for web apps.

</comment></comment><comment><USER9> The idea of saving the rendered version of the app instead of recreating it server-side is very interesting. However I think this implementation limits its usefulness.

It would be very interesting to explore just sending the newly created page back to the server and then using it for new page loads. The state could be updated after the load. Code is needed to update the state anyway in normal usage.

<comment><USER10> You're suggesting people send their html back to the server when they've finished reading it.

<comment><USER9> Actually I thought it would go back to the server immediately after loading and rendering. Having more time to think about it, I think maybe it's a stupid idea. You could render it in the server with ghost or something just as easily.

</comment></comment></comment><comment><USER11> Unfortunately local storage is limited by 5MB. It's probably enough for simple apps, but will it work with any real world projects?

<comment><USER2> The app saves its state in whatever form it wants. The demo saves it in localStorage that is very limited. One really should look at something better like IndexedDB or WebSql (or something that hides the technical details, like localForage or PouchDB).

<comment><USER11> WebSQL is not supported by IE nor FF, and is limited by 50 MB.

IndexedDB is limited by same 50MB, 5MB on mobile, and is only partially supported by IE, Safari and iOS.

<comment><USER2> That's why I recommend using PouchDB to work with whatever API is available. Storage limits are harder to work around, but if your HTML snapshot weights more than 50MB (or even 1MB!) that it is a problem by itself.

</comment></comment></comment></comment><comment><USER12> Curiously enough, the Ember TodoMVC[1] doesn't seem to suffer from the issue here, at least for me. Can anyone say why? I don't know much about Ember.

[1] [http://todomvc.com/examples/emberjs/](http://todomvc.com/examples/emberjs/)

<comment><USER2> seems to flash for me, add a few todos and then hit reload

</comment></comment><comment><USER13> I did something similar for a Backbone app. I have the last rendered html on cache (when it is too big I have to use the server, although I store it as plain static html). Only after 'instant render' the page I find exisiting DOM elems and create+assign the corresponding views. Voilà!

<comment><USER2> Exactly!

</comment></comment><comment><USER14> This makes me shake my head for so many reasons. Way, way too clever for 99% of Web applications.</comment>


The 85 Most Disruptive Ideas in Our History - <AUTHOR> http://www.businessweek.com/features/85ideas/

<comment><USER2> The iPhone isn't really the first smartphone. It made the smartphone popular.

Oh well, the article is about disruptive ideas, so it counts.

</comment><comment><USER3> Silly, IMHO. They seem to lack a sense of history and what is important and are blinded by the events of the moment.

</comment><comment><USER4> I expected a 85 page slide show, but the (single) page is actually quite enjoyable.</comment>


Request for Feedback: an "opportunity fund" for underrepresented founders - <AUTHOR> https://earnestcapital.com/help-design-the-earnest-opportunity-fund/ <comment><AUTHOR> Hello Hacker News, looking for feedback on how we could expand our "funding for bootstrappers" model to better serve underrepresented founders. Suggestions, comments, critiques, all very much welcome here. Thanks.

</comment><comment><USER2> I agree with the thoughts and suggestions already expressed in this thread. It's great that you guys are thinking about this and want to make a difference but I will also add that I've looked at the team in Earnest Capital and there is zero diversity, which for me is a huge problem. That may be part of the reason why your portfolio/deal flow is mainly white male-owned companies. As a black female founder building a product targeting women, looking at your team structure, I would not consider applying to your fund because I wouldn't be convinced that you will understand my product/the need I'm addressing. Having a diverse group of individuals in the investment team is key because at your current state, you won't be able to quickly spot or identify with the nuanced experiences that minority founders face.

I personally think that the first step you need to take is improve on the diversity of the team or else you will still run into the same problems you're currently facing.

Also, reaching out to communities that put diversity at the heart of what they do would be a good step to take. I am based in London and there are a handful of communities with outstanding but overlooked founders - happy to share them with you if you want.

Happy to help in whatever way I can to make this a reality!

</comment><comment><USER3> Love what you're trying to achieve here.

My main worry is how you can do this at a non-net-negative return for your fund while also not coming across as predatory to the people you're trying to help.

> We often talk about 'bootstrapping' but very few founders actually build a > business with literally no outside capital, savings, or help. In our > personal experience, from asking lots of founders in private, a large > portion used their own accumulated savings from a high paying job, had a > spouse that covered the bills, had a windfall or inheritance, or relied on > loans and help from family members. Every one of these is systematically > harder in some way for founders of color, female founders, LGBTQ founders, > and founders from underprivileged geographies. Note, none of these are > insurmountable and we all know folks in every one of those categories who > has successfully bootstrapped a business, but bootstrapping as we know it is > systematically tilted against underrepresented founders in a way that we > believe justifies a countervailing strategy.

You seem to be arguing (and I'd agree) that underrepresented founders find it much more difficult to get to the point at which Earnest (and others) would normally invest. What with them not having access to the considerable personal or F&F capital necessary to get there.

So it seems like you'd have to invest earlier, when there's more risk.

Now, I'm happy to believe that - because these founders are underrepresented - you can find 'better' founders overlooked by others.

But still, at that early stage, the risk will be significantly higher than at the P/M fit, post-revenue stage.

So I'd love to hear how you plan to offer terms that won't be called out as predatory (or somehow taking advantage of underrepresented founders) by others?

</comment><comment><USER4> Some thoughts that spring to mind:

The first step to becoming more diverse is acknowledging the lack of diversity.

To get diversity more effort needs to happen in reaching out, most people don't do this because it requires extra work. As you mentioned, many people feel these things are not for them. Or perhaps they lack the confidence/skills/bravery to take things or even to enquire about the investment.

I saw the founders of Code Untapped give a talk the other week. They run hackathon/meetups and they are always experimenting and changing the times of them to try to reach more people who otherwise might not be able to attend.

And if you want to reach a diverse audience have diversity in your team, easier said than done, I know. But if you do things like Venture Partners, you could make a point of only having Venture Partners who are minorities. But also be prepared for white males to kick up a stink if you do this <\--- I see this a lot!

<comment><AUTHOR> Agree with all of this. Thanks Rosie!

</comment></comment><comment><USER5> I don't have much input on the underserviced founder description. As someone in Florida where we literally 2-3 real VC's, I consider our market underserviced regardless of race, gender, creed. But I understand and support helping any Founder, whatever the angle for identifying them.

Regarding your underlying criteria here: "We expect founders to find a way to build and launch a product, get some amount of revenue traction, and have a roadmap to build the company profitably without relying on too much additional outside capital."

This resonates with me and I would like to provide some fruit for thought. I am actually in the process of launching a startup studio with the investment thesis of:

<$50k for startups with large TAM's (>$b) that can get product market fit in less than 90-days of the first $1 invested, and that can generate +EBITA within 12-months of the first $1 invested for $1-3m Seed.

Here is feedback on my model and thesis. It may help you refine yours and if I can be

I am going the studio route because I believe you need distributed teams. (specifically senior management, dev (support), design (brand/product)) in order to gain economies of scale in order to build such disruptive ideas efficiently.

I call this concept a "Venture Lab" because unlike a studio I want outside founders to join with their ideas. So imagine an accelerator married with a studio.

Here are some things to consider when your focusing on profitable startup building:

Speed is the key. The longer it takes to build, the more burn. Hence my requirement of product market fit super fast. I define product market fit as the ability to generate revenue organically or through profitable customer acquisition models.

If your going to be profitable fast... you have to be lean. Many vc's want "great teams". Unless the team has wealthy parents or some other means, they need to get paid. Therefore using precious cash. It's a conundrum.

Furthermore most founders have never spent tens of thousands or hundreds of thousands or millions of dollars that they are responsible for. It's really different when your signing the check. If you can't afford a great CFO who is doing a burn analysis and showing you your runway every few days you can quickly crash and burn. Your certainly not going to build a great product if your constantly running out of cash and fundraising (what I call "scrambling").

So to recap: Speed > Lean > Cash/Resource/Time Management

Hence why I feel we (experienced distributed team called "the Lab") have to be active in the venture building with the Founder.

The model has thousands of years of evidence of working: war fighting. Whenever you see numbers of soldiers deployed to a conflict, only 10% are actually war fighting. The rest are support, supply chain, logistics, etc. supporting the 10%. Same concept.

So the gist of my feedback is Don't just write a check to underserviced founders, because their going to need a lot of support to: have a plan.

<comment><AUTHOR> Good feedback. I agree with your first point. I think that outside of Silicon Valley we actually have a crisis of lack of access to early-stage capital for entrepreneurs (and hence the multi-decade decline in new business starts).

There are a lot of both underserved and underrepresented entrepreneurs right now and and it's a real challenge to define the area of focus.

Point is well taken about not just writing a check. I don't get into it in this specific post because the pitch is basically Typical Earnest + a focus on underrep'd founders. But Typical Earnest already includes a community, shared resources, and access to an awesome group of mentors: [https://earnestcapital.com/about/](https://earnestcapital.com/about/)

<comment><USER5> Crisis is the perfect word.

Will read more about your offering compared to others. Sounds like your ahead of the curve so to say!</comment></comment></comment>


Ask HN: Why are you still working for the NSA? - <AUTHOR>

I'm sure there are quite a few NSA employees reading this and following the whole media discussion with great interest.
I'm genuinely curious - what keeps you there? Do you still believe in the "mission"? Are you comfortable with what is going on, and basing your livelihood on programs that so many people are against?
Let's have the "other side" the story. If you've got a case to make, I'm sure we'd all love to hear it.
Feel free to register a throwaway account and discuss. <comment><USER2> Many people (not nearly all) on HN seem to live in some sort of bubble, where all they have to do to find another job is open up their email and carefully select the best option out of dozens of recruiting emails from the nation's largest companies.

Finding a job isn't easy for everyone. One thing that often accompanies technical ability is a distinct lack of social skills. Other people just suck at writing resumes and no matter how many peers and professionals review their resumes, they just don't seem to work. Some people excel in both areas yet have disproportionate amounts of bad luck.

I spent close to a decade in the military in an industry closely related to IT. I had also been playing around with computers for almost two decades. When I got out of the military I lived close to DC, the largest market for government contractors. I had a clearance, an outstanding performance record and an abundance of relevant experience. I started working on my resume a year from the time I was getting out of the military, and started applying for jobs almost immediately. My problem wasn't that I failed during interviews, I just simply couldn't get an interview to save my life. Throughout this entire time, I kept having professionals and friends alike review my resume. I still couldn't find a job in the one part of the world where it should be easy to find a government job.

Eventually I moved to a new location, taking the first shitty job that was offered to me, working for a government agency. That job eventually fell through, but I now hold a position at a similar agency. Before I found the job, I was days away from running out of the money that I had saved up while I was still in the military. When I started at my second civilian position, I was once again days away from running out of money. If I lost this job, I'd probably be completely fucked. I have a wife and children, so I don't really have the option to live on a friend's sofa eating ramen noodles every day, so I have to work.

That's not to say I'm unhappy, I just find it laughable how often people act like changing jobs is such a trivial affair on HN.

As far as the moral implications go, I believe in the underlying mission of my organization (which is not the NSA). I don't always believe in the higher- level policies or the programs that they implement to achieve those goals, but I feel that we should strive to change those things through the political process, even though its broken.

Hell, it's not like anyone should be surprised at everything that got leaked, I've been reading in the news for over a year that the NSA has been building one of the world's largest data centers in Utah. The suspected purpose has always been claimed to be the warehousing of American communications, yet suddenly everyone decides to pay attention.

It's also important to note that there is a distinct difference between responsible disclosure and delivering sensitive information to Assange/China/Russia/etc.

<comment><USER3> The idea of considering your job trivial is a benefit, and computer development has the succinct ability to share efforts amongst a huge area of disciplines, and thus it is that a hackers career is largely 'hot-swappable' around the world.

I'm the son of a man who stayed at an engineering job for 25 years. This is his largest regret, as it pigeon-holed him into the mentality that he was incapable of applying his vast talents elsewhere in the engineering field. As such, the company that he pledged allegiance to made every effort to keep his pay and benefits below the industry standard, and this was made possible by the environment he hired himself into initially.

Computer development is one of the few jobs that you can seriously apply yourself at no matter where you are in the world. Why not take advantage of that fact?

Responsibilities are another problem. It's a personal issue if you've decided to burden yourself financially with children, a mate, and things that are generally seen as the normal routine of adulthood, but that, like I said, is a personal issue that must be dealt with on a person to person basis.

As for those with technical ability being more likely to also have social problems -- how is limiting the exposure to interviews and social interactions exactly going to help improve the individual we're talking about? It's important to be flexible. To defend a position by saying that person X is deficient too much in this way to have the means to get job Y so he must do job Z is a recipe for disaster. Social interactions are practiced, and the assertion that we should dissuade those that lack in experience from practice is wrong, in my opinion.

Of course , there are legitimate roadblocks in social psychology that could prevent them from landing a job with no fault of the person, but if they got that initial job it means someone saw something in them that they related to value, and if that happens once it can happen again for them. No reason to think that anyone, ever, is stuck.

<comment><USER2> >As for those with technical ability being more likely to also have social problems -- how is limiting the exposure to interviews and social interactions exactly going to help improve the individual we're talking about? It's important to be flexible. To defend a position by saying that person X is deficient too much in this way to have the means to get job Y so he must do job Z is a recipe for disaster. Social interactions are practiced, and the assertion that we should dissuade those that lack in experience from practice is wrong, in my opinion.

I never suggested not trying or giving up. I was simply relating that for such people its often extremely difficult to find a job. The fact that I keep trying is the only reason I'm not living in my car right now.

</comment></comment></comment><comment><USER4> I don't work for the NSA, but I've worked at a contractor for several research oriented things they've been involved in (unofficially - the money comes through a non-DoD part of the government). Because what I worked on was geared towards research in language technology and related fields, my view might be a bit skewed, but here's my impression.

There's a fair number of people who do seem to believe that they're working to help secure the country. Many seem to stay where they are because they get paid well and work on what they're interested in (many PhDs who joined out of grad school or shortly thereafter.

One thing I find interesting about all of this NSA spying stuff is how it relates to the pervasive concern I've seen on the part of people working in intelligence about potentially using data containing personally identifying information, particularly of US persons. I do wonder if the scale, scope, and invasiveness of the spying as reported is actually that great.

<comment><USER5> > get paid well and work on what they're interested in

This is a common reason in pure math and theoretical computer science. There are not a whole lot of places that will give you a good job to do basic research. Tenured professor is another one, but hard to come by, and has a different set of tradeoffs.

If you do certain kinds of applied research (e.g. machine translation) you can do it at Google, but Google is not tripping over itself to hire number theorists to do actual number-theory work (maybe they would hire a number theorist, but to do something else).

<comment><USER4> The people I dealt with we're all in the language technology field. They tended to be a bit on the older side, so maybe they wound up there before there were the kinds of research opportunities you get in industry these days.

</comment></comment></comment><comment><USER6> If I may step into their shoes...

Simple answer would be, "to pay the bills". I'm sure the vast number of people working for government agencies (engaged in espionage or not) are simply there to stay fed, clothed and sheltered. The NSA, CIA, FBI etc... are all vast megaliths with intricate internal structures, bureaucracies and buttload of paperwork (digital and dead tree) that needs processing by humans.

Humans that need jobs. That's it. They may feel some sense of patriotism in what they do, but I think most of them are just doing a job.

It's the tobacco farmer syndrome.

</comment><comment><USER7> Having read (only) a few books on the history of the american intelligence community, I suspect most people who work there believe in the work that they do. While domestic spying is obviously a black mark in the history, I suspect that the good work thats been done there is fairly substantial. We can actually thank the NSA for some security technologies that are used regularly (and are open source).

Also consider that the president OKed this happening and the public isn't yelling for revolution nor impeachment.

</comment><comment><USER8> It will be an amazing day for the internet if an active NSA employee or contractor risks their career to post here. A lot of the people working in these roles love the thrill of being a part of the inside and also love the idea that they are trampling people's rights because they are part of 'true America.' They are put into much better living standards than almost everyone. These living standards can be easily taken away.

</comment><comment><USER9> Honestly if I worked for the NSA, and lets assume that the NSA was behind Stuxnet etc, and I was involved; I would be very proud of my work, how many people can genuinely say that they created a computer program that directly slowed the nuclear program of another nation state?

Also to be fair, you never hear about the good, only the bad. How many domestic terror cells has the NSA stopped by spying on its people? Who knows... because these facts don't get disclosed. I think having time to think about the revelations recently that the phrase "you have to be cruel to be kind". What if the NSA did not spy on people in its own country, and then America was nuked from the inside... they would be held accountable along with many other alphabet soup organisations for not doing their jobs properly.

</comment><comment><USER10> Blinders: military personnel can't read The Guardian, gagged, `Need to Know' sequestered. Why risk being a Chatty Kathy on HN when, this week, we read a General is being investigated for opening his big fat mouth. At Fort Meade, `Hackers' are criminals. I imagine any NSA or its contractors reading this are tasked to identify the outliers.</comment>