Care to clarify why you believe references and message passing are mutually exclusive?Seems like a good idea in theory until you actually do it. Pretend you have a set of data you want to work on with multiple threads. Like for multithreaded pathfinding or image processing. Suddenly you're forced to copy data. (In webworker's case you can't copy more than 1 MB of data). Doesn't matter really though since the time waste copying is so expensive that you've effectively negated any performance increase. That's not even counting the copying of the data back. The alternative is to just pass in a reference and go "hey you 2 threads work on half the data each and get back to me when you're done". No copying overhead. You'll notice in that situation that neither thread even had to touch the other's data at the same time so no lock was needed.
I can't agree with you there. The locks & mutices threading model you are talking about is vastly inferior to Erlang-style concurrency (i.e. message passing, no shared mutable state).
Regarding concurrency:They're just taking the stupid idea of webworkers which was a useless feature and just throwing it into their language instead of implementing actual language locks and mutices.
An isolate is a unit of concurrency. It has its own memory and its own thread of control. Isolates communicate by message passing (10.14.4). No state is ever shared between isolates.
Dart's Isolate is likely the result of the work they have done on coroutines in Google's Go - they quite closely resemble one another, although isolate appears to be a little more general (can spawn OS threads as well coroutines).
Concurrency is an abstraction, not an optimization; the basic bronze age concurrency primitives are quite obviously useless in this regard, when compared to Erlang-style message passing.
The only time it makes sense is when your passing off like a few values or a small array for heavy processing. Then again you lock out the bigger uses of threads that way. The lock and mutex allows everything without restrictions.