The ANSA Architecture as a Framework
for Heterogeneous Execution Environments

David Iggulden
APM
Poseidon House
Castle Park
Cambridge
United Kingdom CB3 ORD
di@ansa.co.uk

Abstract
 
The objective of the ANSA architecture for Open Distributed Processing
is to provide a framework that will allow the construction of
world-wide computer-based systems that:
    o	are implemented using heterogeneous technologies from
	many vendors
    o	are owned and managed by many organisations
    o	may scale to sizes larger than the telephone system
    o	can evolve gracefully.  

Issues of heterogeneity and the idea of distribution transparency that
characterise distributed systems are considered and further notions of
separation, configuration and federation are noted.  The ANSA
Architecture uses a cognitive framework to abstract from a complete
description of a system. Five cognitive levels are identified and
labelled as follows: Enterprise, Information, Computation, Engineering
and Technology. The paper focuses on the support provided in the
architecture for Enterprise concerns and describes the basic
mechanisms for heterogeneous execution environments, which provide the
basis for support of the ANSA technical objective.  Final sections
review design issues and the current status of the work.