System Architecture
Information System Architectures: From Art to Science
Peter C. Lockemann
Fakultät für Informatik
Universität Karlsruhe
Postfach 6980
76128 Karlsruhe lockeman@ipd.uka.de Abstract: The presentation claims that architectural design plays a crucial role in system development as a first step in a process that turns a requirements specification into a working software and hardware system. As such, architectural design should follow a rigorous methodology – a science – rather than intuition – an art. Our basic premise is that requirements in information systems follow a service philosophy, where services are characterized by their functionality and quality-ofservice parameters. We develop a design hypothesis that takes the service characteristics into account in a stepwise fashion. We then validate the hypothesis for traditional database characteristics, demonstrate for novel requirements how these would affect architectures, and finally apply it to the current 4
-tier server architectures. 1
Motivation
Information systems grow in the diversity of their application domains, number of users, and geographic distribution, but so does their complexity in terms of the number and functionality of components and the number of connections between these. An almost bewildering multitude of architectural patterns has appeared over the more recent past, that try to bring order into the evolving chaos. To name just a few of the buzzwords, take layered architectures, n-tier architectures, component architectures, middleware, vertical architectures, horizontal architectures, enterprise this-and-that.
Nonetheless, it seems that these architectures have enough in common so that one suspects that they just look at similar phenomena from different perspectives, emphasize different aspects, or explore issues to different depths.
The premise of this paper is that architectural design plays a crucial role in system development. Unfortunately though,
Peter C. Lockemann
Fakultät für Informatik
Universität Karlsruhe
Postfach 6980
76128 Karlsruhe lockeman@ipd.uka.de Abstract: The presentation claims that architectural design plays a crucial role in system development as a first step in a process that turns a requirements specification into a working software and hardware system. As such, architectural design should follow a rigorous methodology – a science – rather than intuition – an art. Our basic premise is that requirements in information systems follow a service philosophy, where services are characterized by their functionality and quality-ofservice parameters. We develop a design hypothesis that takes the service characteristics into account in a stepwise fashion. We then validate the hypothesis for traditional database characteristics, demonstrate for novel requirements how these would affect architectures, and finally apply it to the current 4
-tier server architectures. 1
Motivation
Information systems grow in the diversity of their application domains, number of users, and geographic distribution, but so does their complexity in terms of the number and functionality of components and the number of connections between these. An almost bewildering multitude of architectural patterns has appeared over the more recent past, that try to bring order into the evolving chaos. To name just a few of the buzzwords, take layered architectures, n-tier architectures, component architectures, middleware, vertical architectures, horizontal architectures, enterprise this-and-that.
Nonetheless, it seems that these architectures have enough in common so that one suspects that they just look at similar phenomena from different perspectives, emphasize different aspects, or explore issues to different depths.
The premise of this paper is that architectural design plays a crucial role in system development. Unfortunately though,
References: Integration von Datenübertragungstechnik und Datenbanktechnik. dpunkt.verlag. 2003 (in German) VLDB Conference. 2002 [As79] Herzog, U.: Effiziente Konsistenzprüfung in Datenbanksystemen. Infix. 1996 (in German) [HR99] Härder, T.; Rahm, E.: Datenbanksysteme: Konzepte und Techniken der Implementierung. Springer, 1999 (in German) [Lu02] systems. Submitted for publication. 2002 [St02]