[numpad0]

I had once thinking about this type of system, and later found that the SNMP(1988) as well as NIST/Army 4D/RCS project(1980s) had this train of thought before I was even born. Now I'm wondering why this type of distributed, synchronized, hard realtime decision making framework don't seem to exist as some Apache Foundation project or something. It just sounds right and massively useful but I can't find an implementation, at least on public Internet -- why?

[icegreentea2]

There are a few layers to your question.

If you mean distributed to mean "over multiple computers", then ya... this is a really specialized field. Your ability to synchronize and maintain hard real-timeness between computers is completely dependent on IO and hardware features, and topology. This makes it much harder to make a generalized framework.

We we ignore the distributed portion, then you're describing a real-time operating system - in which case something like https://www.freertos.org/ might fit the bill?

[numpad0]

I mean realtime inter-node message passing in a tree topology network, with message frequency associated to edges, like shown in [1]. Each nodes might run on its own CPU clocks, but message exchanges occur realtime, progressively faster at each depth, and the system as a whole(what "Autonomous System" probably supposed to mean) runs as a slow but coherent realtime cluster.

Perhaps the idea that message passing has to happen realtime is something obvious or elementary to military/defense/aerospace from technical requirements or experiences fighting fog of war etc., but to me it was dumbfounding new and I guess it might also be for the general public?

1: https://en.wikipedia.org/wiki/File:4D-RCS_reference_model_ar...

[pjc50]

It's not really a framework that you implement, more a process for making an implementation?

[zie]

See the Beam/OTP as part of Erlang and now Elixir, Gleam, etc.

Erlang came out of Ericcson when they were building giant telephone switches.

Nowadays things like RabbitMQ and WhatsApp run on the Beam VM.

The beam handles both local and remote nodes, mostly transparently.

Then there are things like Nomad or k8s which try to tackle the problem more like *nix(linux/BSD/etc) does, but across multiple nodes. These are not meant for hard real-time systems like launching rockets obviously, not even for soft real-time.

[StreamBright]

Even though you can achieve pretty good latency with Erlang because of the lack of global memory (most if not all allocation is local to an Erlang process).

[mstipetic]

That’s mostly how kubernetes works also. It’s not that uncommon of a pattern

[StreamBright]

This is not how Kubernetes works. The concepts are completely different (pod, allocation etc.)

[mstipetic]

all the main controllers work by running a reconciliation loop constantly, what are you talking about?