Components and Web Services Inhibit Quality of Service

							Components and Web Services
    Considered Harmful
  Inhibit Quality of Service

           Bob Vavra
            Unisys
   What do we do in handcrafted TP systems
   that isn’t available commercially?

    • Optimization of a deployed TP system
         – Optimize the non-functional attributes
           • Performance, capacity, availability, durability, reco
            verability, maintainability, …
    • Continuing optimization by dedicated team
         – Separate from development projects




Unisys                                                               2
   Reusable Components and
   Web Services

    • Have visible well-defined functional
      characteristics
         – Interface definition, transaction semantics, and
          security
    • Have hidden implementations
         – Hidden non-functional attributes




Unisys                                                        3
   Non-functional attributes are important




Unisys                                       4
   Expand Definitions of
   Component and Web Services

    • WSDL should include non-functional attributes
      of the implementation
         – Useful to application architects, designers, and
           optimizers
         – Useful to component suppliers
            • Reinforces the notion that implementation quality
              does matter
    • Some research underway on QoS for
      components, e.g., in the real-time community


Unisys                                                            5