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Comment by imtringued | Hacker News Reader

Not only does the author ignore the huge progress in conventional garbage collected languages like Java, he also dismisses GC as inherently flawed despite the fact that the common strategy of only having one heap per application has nothing to do with garbage collection. In Pony each actor has its own isolated heap which means the garbage collector will only interrupt a tiny portion of the program for a much shorter period of time. Hence the concept of a stop the world pause is orthogonal to whether you have a GC or not. One could build a stop the world pause into an RC system through cycle detection if desired.

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I’m out of my league so this may be dumb, but does any language or VM or whatnot have a combined system where each thread has its own heap, and you can talk by passing messages, but they also have a common heap for larger data that’s too expensive to pass around, but at the cost that you have to be much more careful with lifetimes or have to manage it manually or something?

I believe Nim works this way, among others.

If you squint at it right you could say C works that way: you have many processes each with their own heap and they can pass messages, but if they want larger data that's too expensive to pass around you can use shared memory.

That’s just IPC, nothing inherent to C.

Sure, you can do this in a lot of languages. I gave C mainly because it's the "native language" of Unix.

I believe Erlang works this way.

In the Erlang VM, each Erlang "process" has its own garbage collected heap [1]. There's also an ETS module for more efficiently storing and sharing large amounts of data, but data stored in ETS is not automatically garbage collected [2].

[1] https://www.erlang.org/doc/apps/erts/garbagecollection [2] https://www.erlang.org/doc/man/ets.html

Dart

> he also dismisses GC as inherently flawed

It's a compromise, on memory consumption and performance. Modern GCs are minimising the impact of those factors, but they still remain a part of the design.

RC is a performance compromise.

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