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Comment by only_as_i_fall | Hacker News Reader

In a vacuous sense, but in practice you almost always use asynchronous code to achieve concurrency.

The canonical Microsoft tutorial on async spends about half its time talking about hiw to make your code concurrent to take advantage of async.

https://docs.microsoft.com/en-us/dotnet/csharp/programming-g...

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Concurrency does not require multi-threading. Maybe you mean parallelism? Concurrency can still be really valuable in the context of a single threaded application.

If a program wants to perform a task in an async way without delegating it to an external program (like a database server or the OS' I/O system), it has to use threads, right? I think the point is that concurrency, for some tasks, basically requires multithreading. Not for the parallelism benefits, but just to be able to make concurrency possible for a task that requires blocking a thread.

Concurrency is more about having order independent units of computation. You can concurrently run operations on a single thread, although there is less benefit if no IO is involved. It's not something you'd likely do in practice unless there was IO.

I did mean parallelism, but I think the point stands. There's very little practical use of async await outside of multithreading.

Syntax sugar aside. Wasn’t the simple scalability of single threaded async nodejs main selling point?

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