There’s no much to write about E’s concurrency model after you read this enlightment (from E in a Walnut):

Multiple threads form the basis of conventional models of concurrent programming. Remarkably, human beings engage in concurrent distributed computing every day even though people are generally single threaded ([...]). How do we simple creatures pull off the feat of distributed computing without multiple threads? Why do we not see groups of people, deadlocked in frozen tableau around the coffepot, one person holding the sugar waiting for milk, the other holding milk waiting for sugar? The answer is, we use a sophisticated computational mechanism known as a nonblocking promise. Let us look at a conventional human distributed computation. Alice, the CEO of Evernet Computing, needs a new version of the budget including R&D numbers from the VP of Engineering, Bob. Alice calls Bob: “Could you get me those numbers?” Bob jots Alice’s request on his to-do list. “Sure thing, Alice, I promise I’ll get them for you after I solve this engineering problem.” Bob has handed Alice a promise for the answer. He has not handed her the answer. But neither Bob nor Alice sits on their hands, blocked, waiting for the resolution. Rather, Bob continues to work his current problem. And Alice goes to Carol, the CFO: “Carol, when Bob gets those numbers, plug ‘em into the spreadsheet and give me the new budget,okay?” Carol: “No problem.” Carol writes Alice’s request on her own to-do list, but does not put it either first or last in the list. Rather, she puts it in the conditional part of the list, to be done when the condition is met–in this case, when Bob fulfills his promise. Conceptually, Alice has handed to Carol a copy of Bob’s promise for numbers, and Carol has handed to Alice a promise for a new integrated spreadsheet. Once again, no one waits around, blocked. Carol ambles down the hall for a contract negotiation, Alice goes back to preparing for the IPO. When Bob finishes his calculations, he signals that his promise has been fulfilled; when Carol receives the signal, she uses Bob’s fulfilled promise to fulfill her own promise; when Carol fulfills her promise, Alice gets her spreadsheet. A sophisticated distributed computation has been completed so simply that no one realizes an advanced degree in computer science should have been required. In this simple example, we see why human beings never get trapped in the thread-based deadlock situations described endlessly in books on concurrent programming. People don’t deadlock because they live in a concurrent world managed with a promise-based architecture. And so it is withE.

Why we people stick with that evil and bad multithreading stuff?