The reason I bring this up is because I've come to the realization that this could be an "answer" for doing effective multitasking on the P2. Now, I acknowledge that not everyone thinks this is a question that's actually being asked and that with 16 cogs available, it's just not a concern. Except, I think it is a concern. "Asynchronous" does not mean "parallel". Using additional cogs to perform asynchronous tasks has all sorts of issues that you have to take into account (much like using threads does on a modern multi-core processor). One of the advantages of using a single thread (or, in this case, cog) is that every asynchronous task is guaranteed to run serially relative to each other, significantly reducing concurrency issues. Further, when working in an I/O bound environment (which I think the P2 clearly qualifies as), appropriate use of the asynchronous model allows for more effective use of the cog (e.g. still do other meaningful work while waiting for I/O to complete). And, if your language of choice supports the asynchronous model (e.g. "await"), you can still write your code in a mostly sequential format (the way we tend to think about our code anyhow). I'm not saying that a single-cog asynchronous model should be used instead of multiple cogs, but that each approach has their place. As it stands now, the Propeller only really encourages one approach (use multiple cogs). This, in turn, reinforces the mindset of "just use another cog", which ends up translating to "just use another thread" on other platforms.
While I hope to see a flavor of JS running on the P2 that encourages the asynchronous model, what I'd really like to see is support for asynchronous programming in Spin. I realize this is not a simple undertaking and I am not asking for it to be added now. This post is more about getting others to also think about the subject. Not only do I think this is important from an educational perspective, I think we will start to see more people coming to the P2 who are already comfortable with that model (and might even expect it). As a result, I think it's a worthwhile subject to keep in mind over the next few years.