Even before that, this is ultimately about that fact that an ISA for a general-purpose computer can be seen as a way to abstract away parallelism. Even in your

Even before that, this is ultimately about that fact that an ISA for a general-purpose computer can be seen as a way to abstract away parallelism. Even in your favorite assembly language, the effects are largely supposed to happen one after another. That abstraction is leaky, but the alternative is VLIW machines - even in that case, you probably end up using a compiler so that you don't have to worry about parallelism. Reasoning about parallel things is hard, that's why we spend so much time trying to avoid it ¯\_(ツ)_/¯