[erlang-questions] Light-weight operating systems supporting Erlang in production web servers

[Richard A. O'Keefe]

On 21/09/17 10:23 PM, Jesper Louis Andersen wrote:
> On Wed, Sep 20, 2017 at 12:50 AM Richard A. O'Keefe <ok@REDACTED
> <mailto:ok@REDACTED>> wrote:
>
>     One question.  I can get a
>     "Raspberry Pi 3 Model B with 1.2GHz 64-bit Quad Core and 1GB Ram"
>     for NZD 69 including tax and run Erlang on it.
>     (Hmm.  Next time I have some spare cash I must get one...)
>
>     Why would I pay NZD300 for a 300MHz board with 64MB of memory?
>
>
> My prediction is that eventually we'll see the "small embedded" market
> squeezed down by rather cheap powerful devices such as the rPI. My
> argument for this prediction hinges on power becoming free in the future
> (due to the current massive advances in solar and wind energy on top of
> better batteries).

I am rather intrigued by the "massive advances in solar";
solar firms seem to be going broke like so many autumn leaves.
Suniva, Solar World, Suntech, Solyndra, ...
I'm old enough to remember when the gospel was that
nuclear power plants would make electricity "too cheap to meter".

Supposing the cost of *generation* to go to zero, that would
not make power "free" because there is still the cost of
*distributing* it (to get economies of scale and to provide
redundancy) and *storing* it.  The makers of the better batteries
will not be handing them out free for the sheer joy of giving,
and nothing lasts forever (maybe the Pyramids; is pyramid power
still a thing (:-)) so they will have an ongoing replacement cost.

We've got people looking at sensor networks here.  In fact I have
a paper on the subject I must finish urgently.  Sensor nodes are
pretty amazing.  In deep sleep they take so little power that you
can practically ignore it compared with leakage in the battery.
If you want a couple of sensors in every field, well, that's
affordable nowadays, but *not* if you want to plug them into any
kind of generator.  (Wires and boxes -- distribution -- will be
much more expensive than the nodes.)  The problem with insolation
is that it varies a lot.  In winter, there are fewer daylight
hours, and the *peak* insolation is about half of what it is in
summer.  At least, that's what the measurements I've been looking
at say.  So you are limited by the average power density available
over the course of a day.  It's enough for a small panel to power
a sensor node, but assuming the technology per se to be free, the
material and processing costs of producing and shipping a panel
looks like making panels dearer than nodes.

Maybe the right choice for sensor nodes might be microbial fuel
cells, e.g., https://phys.org/news/2016-07-urinal-electricity-urine.html
The farmer could recharge his sensors using a different form
of leakage current.  (Half fun and full earnest.  This might
actually work.  It's certainly funny enough to try...)