Report Number: CS-TR-86-1125
Institution: Stanford University, Department of Computer Science
Title: The CAOS System
Author: Schoen, Eric
Date: March 1986
Abstract: The CAOS system is a framework designed to facilitate the
development of highly concurrent real-time signal
interpretation applications. It explores the potential of
multiprocessor architectures to improve the performance of
expert systems in the domain of signal interpretation.
CAOS is implemented in Lisp on a (simulated) collection of
processor-memory sites, linked by a high-speed
communiications subsystem. The "virtual machine" on which it
depends provides remote evaluation and packet-based message
exchange between processes, using virtual circuits known as
streams. To this presentation layer, CAOS adds (1) a flexible
process scheduler, and (2) an object-centered notion of
agents, dynamically-instantiable entities which model
interpreted signal features.
This report documents the principal ideas, programming model,
and implementation of CAOS. A model of real-time signal
interpretation, based on replicated "abstraction" pipelines,
is presented. For some applications, this model offers a
means by which large numbers of processors may be utilized
without introducing synchronization-necessitated software
bottlenecks.
The report concludes with a description of the performance of
a large CAOS application over various sizes of multiprocessor
configurations. Lessons about problem decomposition grain
size, global problem solving control strategy, and
appropriate service provided to CAOS by the underlying
architecture are discussed.
http://i.stanford.edu/pub/cstr/reports/cs/tr/86/1125/CS-TR-86-1125.pdf