Tranquility: A Low Disruptive Alternative to Quiescence for Ensuring Safe Dynamic Updates

• Published in: IEEE transactions on software engineering Vol. 33; no. 12; pp. 856 - 868
• Main Authors: Vandewoude, Y., Ebraert, P., Berbers, Y., D'Hondt, T.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.12.2007; IEEE Computer Society
• Subjects: Adaptation; Application software; Application-aware adaptation; Case studies; components; Componentware; Computer languages; Consistency; Containers; Digital Object Identifier; Distributed objects; Dynamical systems; Dynamics; Information retrieval; Middleware; Operating systems; Placing; Platforms; Running; Runtime; Software engineering; Software systems; Software upgrading; Studies; Sufficient conditions; components; containers; Distributed objects; Application-aware adaptation; Componentware
• ISSN: 0098-5589; 1939-3520
• DOI: 10.1109/TSE.2007.70733

This paper revisits a problem that was identified by Kramer and Magee: placing a system in a consistent state before and after runtime changes. We show that their notion of quiescence as a necessary and sufficient condition for safe runtime changes is too strict and results in a significant disruption in the application being updated. In this paper, we introduce a weaker condition: tranquillity. We show that tranquillity is easier to obtain and less disruptive for the running application but still a sufficient condition to ensure application consistency. We present an implementation of our approach on a component middleware platform and experimentally verify the validity and practical applicability of our approach using data retrieved from a case study.