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An Actor-Based Programming System Disclosure Number: IPCOM000148538D
Original Publication Date: 1982-Jan-06
Included in the Prior Art Database: 2007-Mar-30
Document File: 32 page(s) / 2M

Publishing Venue

Software Patent Institute

Related People

Byrd, Roy J.: AUTHOR [+4]


Roy J. Byrd

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RC 9204 (#40424) 1/6/82

Computer Science 30 pages

An Actor-Based Programming System

Roy J. Byrd

Stephen E . Smith
S. Peter de Jong

IBM Thomas J. Watson Research Center

Yorktown Heights, New York 10598

ABSTRACT: A programming system with which applications are built by defin- ing collections of communicating objects, called actors, is described. The actor programming system provides a uniform environment in which dis- tributed applications can be automated in a highly modular and efficient manner. In order to make this process tractable in today's hardware and software environment, we have accepted certain compromises to the formal theory of actors. We describe our view of the actor system, and an imple- mentation of that view. We also discuss applications built on, and contemplated for, the actor system.

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1. Introduction.

This paper describes a programming system developed within the context of
the System for Business Automation (SBA) project (de Jong (1980), Zloof
and de Jong (1977), de Jong and Byrd (1980)). In SBA, "boxes" represent
business objects like documents, files and memos. Initially humans oper-
ate on the objects. Gradually the business processes are automated by
imparting intelligence to the objects through the 2-dimensional SBA pro-
gramming language. Eventually one obtains an automated business system in
which intelligent business objects communicate among themselves without
human intervention. These systems are naturally distributed, and we
envision a network of processing nodes representing the functional compo-
nents of a business organization, with objects such as memos and invoices
flowing between these nodes.

Rather than take the conventional approach of directly implementing SBA as
a collection of PL/I procedures, we have decided to first develop a pro-
gramming system which provides the kinds of primitives needed by SBA, and
then use it as a base for an implementation of SBA. Such a programming
system should support a collection of intelligent objects which communi-
cate via messages, the ability to create instances of objects which have
common structure and behavior, and the ability to easily modify the behav-
ior of an object.

Our approach is to begin with the actor formalism developed at the M.I.T.
Artificial Intelligence Lab (Baker (1978), Lieberman (1981)), originally
described as a model for computer computation, and adapt it for use as a
programming system. The properties of the actor formalism are ideally
suited to our objective:
1. Instances of actor types are the executing and communicating objects in


the system. Their behavior is specified by a script" and they have
memory which persists between invocations.
2. An actor communicates with other actors, known as i...