About Actalk

Actalk is a testbed for modeling, classifying and experimenting with object-oriented concurrent programming languages.

About OOCP

Object-oriented concurrent programming (OOCP) is a programming paradigm based on the concept of community of active and autonomous entities (called active objects or also actors) which communicate and coordinate by exchanging messages. Object-oriented concurrent programming unifies objects with processes, and message passing with synchronization. This methodology helps decomposing programs in a modular way and exploiting parallel computers to run them efficiently.

(To get general information about Object-Oriented Programming, move to the page which summarizes such links.)


The Actalk testbed is designed to help understanding, classifying, designing, combining, and experimenting with various OOCP languages and constructs. Actalk is implemented and integrated within Smalltalk-80 environment. The testbed includes the kernel which models basic OOCP model (that is serialized active objects and asynchronous message passing), and various extensions in order to simulate various OOCP languages and constructs. They implement various models of activity (serial, quasi-concurrent, concurrent...), communication (asynchronous, synchronous, eager, express...), and synchronization (to control/delay acceptance of messages).

Actalk stands for active objects, or also actors, in Smalltalk.

Purpose and use

Actalk has already been used for pedagogy, experiments, and applications (e.g., as software foundation for various multi-agent platforms).


Current version 3 (implemented in Objectworks then VisualWorks\Smalltalk) has been completed and documented.

Previous versions are archived within Manchester Smalltalk Archive Library which is an invaluable resource of (free) Smalltalk software.

(File VERSION_3.* provides a general info on previous and current versions of Actalk, including how they differ).


You can move to the Actalk directory to retrieve the system and its documentation. (You may have a quick look at the README file.)


You can access to most of the various publications about Actalk, or some more general selection of my papers.

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