TI An Object Management System for Multi-User Programming
environments 

LT CUCS-010-91 

OR COLUM 

YR 1991 

AU Israel Ben-Shaul 

AV ftp cs.columbia.edu:pubreportsreports-1991cucs-010-91?.ps.Z 

AB Multi-user design environments impose specific requirements on
data management that differ substantially from those imposed by
traditional business applications, due to the difference in the
type and duration of frequent operations on the data, and the
structure of and the access patterns to the data.  In particular,
it is desired to enable sharing and exchange of information for
collaborative work while still maintaining data-consistency.  The
object-oriented paradigm seems like a promising approach in terms
of data modeling but imposes difficulties in terms of data
management in multi-user systems.  Two models are proposed here
both are based on the object-oriented data model: A centralized
model in which all data management is done at a single node, and
a distributed model, in which the data management is done in
multiple nodes, each of which is structured according to the
centralized model specifications.  An implementation of the
centralized model for @marvel, a multi-user rule-based software
developmt environment, is given.  The emphasis in the centralized
model is on ``componentization'' of the system into independent,
replaceable components while still coping with the inherent
complexity of the data.  The emphasis in the distributed model is
on exploiting the object-oriented paradigm into distribution, and
it concentrates on data partitioning and dynamic reconfiguration.
The emphasis in the implementation of the model is on specific
problems related to rule-based programming environments, and on
practical implementation solutions.