- Complaints
- lack of referential integrity
- undetected failures
- no control over Quality of Service
- Observations
- dynamic quality of services
- complex interaction
- Requirements
- uniformity, openness, flexibility, orthogonality, layered, platform-independent
- Behavior
- reliable, configurable, monitoring, notification, triggering, thread-safe
- Answers
- object-oriented, components, virtual APIs, callbacks, plug-ins