const PouchDB = require('pouchdb');
const localDB = new PouchDB('db');
const remoteDB = new PouchDB('http://192.168.1.100:5984/db');
// remote db can be a CouchDB or PouchDB server.
I'm using this with React for a mobile app that works offline, and syncs up when a connection is available.
I've been dreaming about a site like this for years. Casual newsreaders need context given to them in a friendly way so they can properly engage with the content. Vox.com explainers are one thing but this is even better. Kudos on launching!!
"Amazon has a secretive unit — dubbed Competitive Intelligence — responsible for ordering large quantities of goods from competitors to analyze their businesses. This division eventually became aware of Diapers.com and its parent company Quidsi, and dispatched M&A chief Jeff Blackburn to initiate acquisition discussions.
Quidsi’s founders originally rebuffed acquisition offers from Amazon. So Bezos’s Amazon sent them a message, Stone [author of a book on Bezos and Amazon called 'The Everything Store'] explains:
“Soon after, Quidsi noticed Amazon dropping prices up to 30 percent on diapers and other baby products,” Stone writes. “As an experiment, Quidsi executives manipulated their prices and then watched as Amazon’s website changed its prices accordingly. Amazon’s pricing bots — software that carefully monitors other companies’ prices and adjusts Amazon’s to match — were tracking Diapers.com.”
Diapers.com revenue growth eventually slowed under Amazon’s pricing pressure, and the founders engaged in acquisition talks, agreeing to a $540 million buyout.
As Stone tells it, Walmart eventually made Quidsi a better offer of $600 million, but it was too late by then.
“The Quidsi executives stuck with Amazon, largely out of fear,” Stone writes."
I haven't found Amazon UK particularly 'cheap' for the past couple of years at least, usually their day-to-day prices are about the same as mainstream and sometimes rise quite markedly for short periods.
Their primary advantage here seems to be centralised shopping and convenience of payment.
An example was a book on which they were offering 3 pence discount on the RRP. Hardly worth bothering about, but very low friction to buy from them instead of another site offering £1 off because my payment and delivery details are already lodged with Amazon.
Given my extensive experience with the (lack of) customer service at Walmart, people often won't bother to price match because they don't want to wait 30+ minutes for someone to flag down the manager, check the prices, etc for a small benefit.
But when there's a big price difference, say on a high-ticket item, it's totally worth the time because you can save money while walking right out of the store with the item, instead of waiting on shipping.
> But when there's a big price difference, say on a high-ticket item, it's totally worth the time because you can save money while walking right out of the store with the item, instead of waiting on shipping.
So high-end baby items (automated swings), TVs, laptops, and the like.
I would rather wait the two days (Prime member) or pay the $4/extra for one day shipping versus having to go to Walmart. Waiting in line for 15-20 minutes to checkout? Possibly not finding the item or its not in stock? Lack of helpful staff (not that I blame them!). Nope Nope Nope.
You joke, but FTP has indeed actually been used to communicate between Earth and a probe. A team at NASA's JPL , led by Vinton Cerf, completed a study of what would be needed for an Interplanetary Internet . There are already IETF RFCs for delay-tolerant networking , which include mechanisms for store-and-forward communications (e.g. each transceiver is a relay).
Science fiction has some great depictions of interstellar communications, such as my favorite by Vernor Vinge, the Hugo award-winning novel A Fire Upon the Deep. It is a most excellent space opera that prominently features an interstellar system like Usenet as part of the plot , as well as superhuman intelligence, physics, and all sorts of other wonderful bits.
Like other embedded systems, spacecraft computers use real-time operating systems (RTOS) and languages:
* The Rosetta probe ultimately runs SCL (Spacecraft Command Language) , a COTS spacecraft programming language developed for sale to the military ; SCL is based on the syntax of Ada 83, which has a long legacy in spaceflight and other real-time applications (e.g. Boeing 777) . However, what are known as Flight Control Procedures (uploaded commands), are written using another language and transformed and compiled into SCL in a two-step process that involves XSLT . On-board Control Procedures, which are procedures the probe decides on its own to run, and handle tasks such as receiving FCPs and sending back telemetry, are written in SCL .
* The Mars rover Curiosity is programmed in C and uses the VxWorks RTOS , which is very much like many commercial embedded systems. It has about 2.5 million lines of code, much of it autogenerated. Curiosity's predecessors, Spirit and Opportunity, used the same software stack, as did their predecessor, Sojourner .
* The Voyager probe, which has now left the solar system and entered interstellar space, uses "...interrupt driven computer[s], similar to processors used in general purpose computers with a few special instructions for increased efficiency. The programming is a form of assembly language." 
* The Space Shuttle was programmed in a custom language called HAL/S (High-order Assembly Language/Shuttle) , as was the Jupiter probe Galileo . The language is descended from PL/I and its compiler is written in a subset of PL/I called XPL.
Very interesting. I didn't think C would be used that much (except for the core of the os of course). I somehow thought of either a specialized language with strong guarantees (such as ADA), or a high level language for IA-like feature.
Which makes me wonder, since this is HN after all, if Rust wouldn't be an ideal candidate for coding this kind of layer in the future. Maybe a compiler targeting VxWorks is in progress somewhere.. ? :))
Anything even remotely new is usually not a candidate for these types of long duration missions. Part of it is institutional inertia, but also partly a desire to use a technology stack that will still be in use decades from now. Even for missions that only take a few years, some of the same people will work on those missions as well as decade plus missions, so you have to hire people who are experts in mature technologies. Institutions like NASA and ESA want to work with a technology stack that will remain stable and which they know will be maintainable by people in the future.
C and languages that compile to C (Fortran is used as well) are often employed since you have powerful control over memory usage.
Source: I work in the aviation industry, where the technologies are different but the lifecycle concerns are very similar.
Sorry, I didn't mean to suggest that all my LED lights were controlled. I have a Hue setup, so I have 3 lights that I have controlled rather crudely with their software. I have a light switch that will turn on the front light from dusk till dawn, I just need time to install it.
Sounds cool! I had a feeling it was Hue. I really wish it was economical to make every switch controllable with something like zigbee but it doesn't seem to make sense even for new construction. Maybe someday...most applications don't need control of every light.