1. Components and Web Services Considered Harmful Inhibit Quality of Service Bob Vavra Unisys

2. Unisys 2 What do we do in handcrafted TP systems that isnt available commercially? Optimization of a deployed TP system – Optimize the non-functional attributes Performance, capacity, availability, durability, recoverability, maintainability, … Continuing optimization by dedicated team – Separate from development projects

3. Unisys 3 Reusable Components and Web Services Have visible well-defined functional characteristics – Interface definition, transaction semantics, and security Have hidden implementations – Hidden non-functional attributes

4. Unisys 4 Non-functional attributes are important

5. Unisys 5 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