[acje]

One of the things I can't see the actor model explain is how to scale an actor vertically, which obviously has it's purpose. Amdahl's law and all that.

However these days we see people build actor frameworks using CSP (golang) and "restricted shared memory" in Rust http://actix.rs

Isn't it ironic? Yet shows that the actor model can be inclusive of many "competing" paradigms, and gain from them, perhaps even need them to scale vertically?

[carlehewitt]

This is a very good question.

Citadels are larger scale Actors which can be incorporated into other Citadels, where a Citadel is an Actor for a systems of Actors (perhaps including IoT).

See the following:

   http://web.stanford.edu/class/ee380/Abstracts/190123.html

[carlehewitt]

Amdahl's law imposes no performance limitation on a system which does not have a sequential part. Having a sequential part is a bad idea because it is a single point of failure.