The term "blocking" has diverged between various communities and it is important to recognize those differences or you'll have dozens of people talking past eac

The term "blocking" has diverged between various communities and it is important to recognize those differences or you'll have dozens of people talking past each other for hundreds of messages as they all say "blocking" and think they mean the same thing, and then get very confused and angry at all the other people who are so obviously wrong (and in their context, they are) but just can't see it. It is obvious that a given "execution context", which is my generalized term for a thread and an async job and anything else of a similar nature, when it reaches for a value from an mmap'd file will be blocked until it is available. However, different communities have different ideas of an "execution context". Threaded language users tend to see them as threads, so while a given thread may be blocked the rest of the program can generally proceed. (Although historically the full story around file operations and what other threads can proceed past has been quite complicated.) Async users on the other hand are surprised here because the operation is blocking their entire executor, even though in principle it ought to be able to proceed with some other context. Because it's invisible to the executor, it isn't able to context-switch. In this case, the threaded world view is reasonably "obvious" but it can be non-obvious that a given async environment may not be able to task switch and it may freeze an entire executor, and since "one executor" is still a fairly common scenario, the entire OS process. (I am expressing no opinion about whether it must block an executor. System calls come with a lot of flags nowadays and for all I know there's some way an async executor could "catch" a mapped access and have an opportunity to switch. I am taking the original article's implicit claim that there isn't one happening in their particular environment at face value.) As long as you do not distinguish how various communities use the term "blocking", you will get very, very deeply nested threads full of arguments about something that, if you just are careful with your terminology, isn't complicated for anyone from any subculture to understand.