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I was gonna say the actor model stems from state machines I believe. It's a nice way to manage state and communication. It reminds me of supervisors and process

I was gonna say the actor model stems from state machines I believe. It's a nice way to manage state and communication. It reminds me of supervisors and processes in general but not program language specific.

hosh 3y ago
Erlang developed the way it did before people started calling it an Actor model. The key characteristic is not a state machine, but that: - first class processes send messages to each other - messages are queued - each process is single execution flow. If you want to reenter code, start another process and send messages to it - process execution can be preempted - values passed in messages are for the most part, immutable. - first class support for “links”, where one process gets notified when another process crashes (basis for supervision trees) The consequences of this design are: - for the most part, you don’t need mutexs - spin locks are cheap - every process can be suspended indefinitely when nothing is in the message queue. This is better than an async reactor. - processes don’t get “lost” (I am looking at you, Nodejs) - processes can receive control messages to suspend or shutdown, restart, etc. Most other platforms have to externalize that to say, K8S and such controls are crude. - errors don’t get “lost” (Nodejs again …) - repl in production, can inspect the whole system live, under load - overloaded systems degrades gracefully instead of locking up
- az09mugen 3y ago
  Erlang did appear after the creation of the actor model. The actor model is from 1973 : https://en.m.wikipedia.org/wiki/Actor_model https://en.m.wikipedia.org/wiki/Actor_model And Erlang is from 1987 : https://fr.m.wikipedia.org/wiki/Erlang_%28langage%29 https://fr.m.wikipedia.org/wiki/Erlang_%28langage%29
  - hosh 3y ago
    https://softwareengineering.stackexchange.com/a/277469 https://softwareengineering.stackexchange.com/a/277469 Looks like I misread it. While the Actor model was conceived before Erlang, the Erlang actor model was developed in parallel. It isn’t a pure implementation of Actors (everything is an Actor, making it closer fo Smalltalk). Only processes are Actors. It also implies that Akka is not a true Actor model as conceived in the originao ‘73 paper. This goes into greater detail on the history: https://www.labouseur.com/courses/erlang/history-of-erlang-armstrong.pdf https://www.labouseur.com/courses/erlang/history-of-erlang-a... In any case, there are not many contemporary systems that uses these ideas.

hosh 3y ago

Erlang developed the way it did before people started calling it an Actor model. The key characteristic is not a state machine, but that: - first class processes send messages to each other - messages are queued - each process is single execution flow. If you want to reenter code, start another process and send messages to it - process execution can be preempted - values passed in messages are for the most part, immutable. - first class support for “links”, where one process gets notified when another process crashes (basis for supervision trees) The consequences of this design are: - for the most part, you don’t need mutexs - spin locks are cheap - every process can be suspended indefinitely when nothing is in the message queue. This is better than an async reactor. - processes don’t get “lost” (I am looking at you, Nodejs) - processes can receive control messages to suspend or shutdown, restart, etc. Most other platforms have to externalize that to say, K8S and such controls are crude. - errors don’t get “lost” (Nodejs again …) - repl in production, can inspect the whole system live, under load - overloaded systems degrades gracefully instead of locking up

az09mugen 3y ago
Erlang did appear after the creation of the actor model. The actor model is from 1973 : https://en.m.wikipedia.org/wiki/Actor_model https://en.m.wikipedia.org/wiki/Actor_model And Erlang is from 1987 : https://fr.m.wikipedia.org/wiki/Erlang_%28langage%29 https://fr.m.wikipedia.org/wiki/Erlang_%28langage%29
- hosh 3y ago
  https://softwareengineering.stackexchange.com/a/277469 https://softwareengineering.stackexchange.com/a/277469 Looks like I misread it. While the Actor model was conceived before Erlang, the Erlang actor model was developed in parallel. It isn’t a pure implementation of Actors (everything is an Actor, making it closer fo Smalltalk). Only processes are Actors. It also implies that Akka is not a true Actor model as conceived in the originao ‘73 paper. This goes into greater detail on the history: https://www.labouseur.com/courses/erlang/history-of-erlang-armstrong.pdf https://www.labouseur.com/courses/erlang/history-of-erlang-a... In any case, there are not many contemporary systems that uses these ideas.