Session:Components--Results

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Deliverables/Results

Paper presentations

• The papers presenting use of connectors showed the benefits of the approach: In one case it showed a way how to bring additional services (such as monitoring, synchronization, etc.,), in other case how to provide mechanisms to avoid failure in the system behavior (such as deadlocks), in third case use of connectors in web services to adjust to the standardized operability.
• Understanding the “good” side of this approach, a discussion about side-effects of this approach continued. Which properties of the systems can be broken in this way, leaving developers unaware of that? Examples – timeliness (response time), resource usage, etc. How this can be avoided, and how to make the developers aware of the implications; what are the mechanisms to provide information and to predict/model the system behavior with/without the connectors?

General discussion

• What characterize differences between component-based and service-oriented approach?
  • We started from some references
    • R. Sessions, "Fuzzy Boundaries: Objects, Components, and Web Services", ACM Queue, Dec/Jan 2004, pg. 40.
    • W. Vogels, "Web Services are not distributed objects", IEEE Internet Computing, Nov/Dec 2003, and at http://weblogs.cs.cornell.edu/AllThingsDistributed/archives/2003_11.html
    • K. Birman, "Like it or not, web services are distributed objects", CACM, Dec 2004, p. 60, and at http://www.cs.cornell.edu/Info/Projects/Spinglass/public_pdfs/Whither%20WS.pdf.
    • From Component-Based to Service-Based Distributed Applications Assembly and Management , IEEE Proceedings EUROMICRO'03, E. Grishikashvili, et al
  • SOA is architectural style with loosely coupled components/services which makes it possible to achieve better flexibility and simpler system modeling, but it cannot provide mechanisms for meeting requirements that are related to system execution context (such as resource consumption or real-time requirements)
  • Services are always related to distributed systems, components not necessary.
  • SOA and CBD have different concerns
  • Service does not lend itself to easy architecture, decompostion, information hiding or decoupling.
  • Components do with implementation, services provide a service.

Instruction Template:Deliverables/Results

Please consider the following points when discussing and preparing your results.

• Prepare an "elevator speech" for your topic: How would you describe the topic in a few sentences? Why is it important? Why should we spend effort on it? The description should be clear and compelling.
• Define the technology/practice gap: What are the needs from industry, what is the current state-of-practice in industry, and what is the current state in research?
  • What do you think are the main problems/gaps?
  • Discuss possible solutions.
  • Priortize/weight the problems/gaps - according to relevance, timeline (what would you like to see addressed next?), size of gap (how close are we to a solution?), and everything else that you think is relevant.
• Other major issues
• Recommendations
• Do you know about related work that is relevant from the discussed topic?