Question

I’ve got very limited knowledge about Erlang, but as far as I understand, it can spawn “processes” with a very low cost.

So I wonder, what are those “processes” behind the scenes?

Are they Fibers? Threads? Continuations?

Answer 1

Also, from the Erlang doc:

Erlang processes are light-weight
(grow and shrink dynamically) with
small memory footprint, fast to create
and terminate and the scheduling
overhead is low.

Source: http://www.erlang.org/doc/reference_manual/processes.html

You might also want to have a look to this:

http://www.defmacro.org/ramblings/concurrency.html

When talking about Erlang processes, it says:

Erlang processes are lightweight
threads. They’re very cheap to start
up and destroy and are very fast to
switch between because under the hood
they’re simply functions. A typical
Erlang system running on a modern
desktop computer can switch between
many tens of thousands such processes.
Processes are switched every couple of
dozen function calls which makes
switches less granular but saves a
tremendous amount of time normally
wasted on context switching.