Mediators in the Architecture of Future Information Systems
Gio Wiederhold
Stanford University
Septemb er
An edited version of this rep ort was published in
The IEEE Computer Magazine March
Abstract
The installation of high sp eed networks using optical b er and high bandwidth messsage
forwarding gateways is changing the physical capabilities of information systems These
capabilities must b e complemented with corresp onding software systems advances to obtain
a real b ene t Without smart software we will gain access to more data but not improve
access to the typ e and quality of information needed for decision making
To develop the concepts needed for future information systems we mo del information
pro cessing as an interaction of data and knowledge This mo del provides criteria for a
high level functional partitioning These partitions are mapp ed into information pro cess
ing mo dules The mo dules are assigned to no des of the distributed information systems A
central role is assigned to mo dules that mediate between the users workstations and data re
sources Mediators contain the administrative and technical knowledge to create information
needed for decision making Software which mediates is common to day but the structure the
interfaces and implementations vary greatly so that automation of integration is awkward
By formalizing and implementing mediation we establish a partitioned information sys
tems architecture which is of managable complexity and can deliver much of the p ower
that technology puts into our reach The partitions and mo dules map into the p owerful
distributed hardw are that is b ecoming available We refer to the mo dules that p erform these
services in a sharable and comp osable wayasmediators
We will present conceptual requirements that must b e placed on mediators to assure
e ective large scale information systems The mo dularity in this architecture is not only
a goal but also enables the goal to b e reached since these systems will need autonomous
mo dules to p ermit growth and enable them to survive in a rapidly changing world
The intent of this pap er is to provide a conceptual framework for many distinct e orts
The concepts provide a direction for an information pro cessing systems in the foreseeable
future We also indicate some sub tasks that are of research concern to us In the long range
the exp erience gathered by diverse e orts may lead to a new layer of high level communication
standards