See the overview for a map of the
|The Actor Model by...
...Carl Hewitt, Henry Baker, Henry Lieberman, Will Clinger, Gul
Agha and others while at MIT, is as foundational a model of computation
as the Turing or Von Neumann models. It is a pure theory of object/capability
computation and of asynchronous distributed Open
System computation. At the Vat granularity, E
is an Actor system.
|The KeyKOS Operating System by...
...Norm Hardy, Charley Landau,
Bill Frantz and others while at Key Logic, is an orthogonally
persistent pure-capability system with a B3-secure architecture.
(B3 is the highest technical category of military security.)
KeyKOS seems to have done everything right. Over and over, when
we ran into hard problems, the heuristic "Do what KeyKOS
did" was our most reliable guide to workable solutions.
|The Concurrent Prolog family of languages
"Udi" Shapiro, Jacob
Levy, Vijay Saraswat,
Ueda, Ken Kahn, and
many others while at the Weizmann
PARC, the Fifth
Generation Project, and several other labs. These are like
Actors, but use Logic Variables as their synchronization &
communications construct instead of Actor mailboxes. This has
advantages and disadvantages. (Strangely, the "logical"
nature of these Horn-clause logic-programming languages made no
contribution to E.)
|The Joule language by...
...Dean Tribble, Mark Miller, Norm Hardy and others while at
Agorics, is E's
most direct and important ancestor. Joule's Channels combine the
virtues of pure Actors with those of Logic Variables. This also
results in Promise Pipelining,
producing a vastly more efficient use of the network and a more
understandable and flexible way to deal with the results of asynchronous
| Original-E by...
...Doug Barnes, Chip Morningstar,
Gordie Freedman, Eric
Messick and others while at Communities.com
("Electric Communities" at the time), started by shoehorning
Joule's elements into a Java base. For 25 years the Actor tradition
assumed that in order to do concurrency control right, we had to
give up sequentiality. While the invention of this deadlock-free
alternative may have required this premise, once invented, E
shows it coexists with sequential programming perfectly well, producing
the first Actor language that's easy to learn.
In Original-E, Communities.com built and went into Beta with
EC-Habitats, a graphically-rich secure system of distributed social
virtual realities. Actual deployment demontrated the value of
the E model,
but also taught us many lessons.
|The birth of E by...
...Mark Miller, Bill Frantz, Jamie
Fenton, Chip Morningstar, Doug
Bornstein, Bob Schumaker,
Rob Kinnemont, Melora Svoboda and others while at Communities.com.
E largely has
the same goals as the Original-E, but takes these lessons into account.
are derived from Joule's Channels and from the Promise architecture
of the Udanax system.
|The Open E
Since spinning out of Communities.com, the currently active
contributors to E
include Mark Miller, Marc
Stiegler, Tyler Close,
Bill Frantz, Ka
Ping Yee, Chip
Shapiro, Norm Hardy, E.
Dean Tribble, Zooko (Bryce Wilcox-O'Hearn),
Terry Stanley, Kevin
Hopwood, Steve Jenson,
Hal Finney, David
Kahn, Vijay Saraswat,
Jonathan Rees, and
a spontaneous Bazaar-style
open-source project, this category is necessarily fuzzy. If you
would like your name added or removed from this list, please let
me, the webmaster-at-erights.org, know.)