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Comment by aneth | Hacker News Reader

" Basically there are two models of concurrency:

    Shared state concurrency
    Message passing concurrency

Wouldn't the node.js style callbacks be a third type of concurrency? It's similar to message passing, but quite different from the user's perspective.

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He did qualify that statement with "basically" and if you think about it, a "callback" function really is just sending a message.

Yes, however at the implementation level, message based concurrency is shared memory concurrency (as I understand anyway.) Callbacks seem to me an entirely a different abstraction.

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