On Friday, 9 October 2015 at 20:16:42 UTC, Jim Hewes wrote:
Yeah, I watched that after I saw your other post with the link.
Thanks. One early question that I have (that someone else also
asked in a comment below the video) is about design and the
granularity of actors. What sorts of things do you define as an
actor? How big does an entity need to be before you should make
it an actor?
Well, I think Hewitt wants actors to be a foundational concept,
but then again this is his baby so he might take it all the way,
just to explore the territory? I've browsed his paper on
ActorScript, which unfortunately doesn't look like a very
user-friendly language IMO, but he apparently thinks that an
Actor could cover just a single expression if you want to. I also
think he is playing with a different type of logic that covers
uncertainty.
https://hal.archives-ouvertes.fr/hal-01147821/document
But... maybe it is more reasonable to use larger units that
represent something in the system we try to model? (Connection,
Account, and so on?)
Another thing I noted was when he said once you get to 1000
cores the programmer knows nothing about the environment. So
rather than figure out new ways to manage these things like
locks and threads, it makes sense to get to a more abstract
level where you don't even deal with it at all anymore.
Yes, just have actors and very efficient message passing and
remove all notions of cores and threads. I think this is where
Pony is heading too.
There was a kind of interesting presentation by Andreas Olofsson
from Adapteva on an Erlang conference I saw on youtube where he
talks a bit about a 1000 core CPU he is designing (manufacturing
is probably a different matter). Each core has 64KiB of local
memory, that's what is called a "scratchpad" which replace
traditional caching so you can get fast memory closer to the core.
https://www.youtube.com/watch?v=WGXPFPKQC2o
Thanks! I'll give it a look. It's probably good for playing
around with to get a feel for it.
I think the Pony feature set is kind of interesting, they are
trying to be innovative. Pony is probably not usable for anything
serious at this stage, but they appear to have proved the type
system to be sound formally so it is interesting to look at, I
think. What they try to do makes sense.
