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A comment on For Better Computing, Liberate CPUs from Garbage Collection. Parent comment

Re:For Better Computing, Liberate CPUs from Garbage Collection by arcticbull on Thursday May 09, 2019 @03:38AM (#19866152)
Am I wrong in thinking that a system comprised of entirely immutable memory doesn't even need a garbage collector? If you built such a system in Rust would not all memory just be deallocated once no longer utilized? The rust principal is (many readers XOR one writer) leads to fully static memory management. This is my point. We need to go back and re-think our language design principals keeping memory management in mind instead of pretending it's a solved problem.

IMO you make a good case.

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Re:For Better Computing, Liberate CPUs from Garbage Collection by mafribe on Thursday May 09, 2019 @03:48AM (#19866202) 

   Am I wrong ...
Yes.

Unless your memory is infinite. Rust also automatically deallocates memory that is no longer used, so it's some kind of GC, but one where the point of deallocation is either statically determined (based on nesting of life-times) or dynamically (using reference-counting). The problem with static dealloc is that the compiler cannot always work out when memory becomes free and must make conservative approximations (see Rice's theorem [1]), the problem with ref-counting is circular data structures (and also the cost in space and time and synchronisation across threads of maintaining an index).

[1] https://en.wikipedia.org/wiki/Rice%27s_theorem

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