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Quality Attributes Elicitation Lab

Retrieval Prompts​

  1. State from memory the four parts of an ATAM-style quality scenario. Why does each part exist?
  2. Give one example each of an operational quality and an evolutionary quality, in scenario form, for a payments platform.
  3. What is the difference between "the system is available" and "the system is reliable"? Give a concrete case where one holds and the other does not.
  4. Why is "fast" not a requirement? What is the smallest rewrite that makes it one?
  5. Give two operational qualities that are routinely confused, and state the distinguishing question.

Compare and Distinguish​

Separate these pairs cleanly, in one or two sentences each:

  • Performance vs Scalability. Which one is about a single request, and which about many?
  • Availability vs Reliability. Which is about being reachable, and which about being correct?
  • Modifiability vs Deployability. A system with high modifiability but low deployability - what does that look like?
  • Testability vs Test coverage. Can a system have high coverage and low testability?
  • Scalability vs Elasticity. What is the additional claim elasticity makes?
  • Functional requirement vs quality requirement. Which one decides whether the other matters?

Common Mistake Check​

Each of these is a real mistake. Identify the flaw and write the repaired version.

  1. "The system should support 1 million users." (requirement)
  2. "Our availability target is 100%." (SLO)
  3. "We need to make the system faster." (proposal)
  4. "Add caching everywhere to improve performance." (architectural move)
  5. "We already have unit tests, so the system is testable." (claim)
  6. "Security is a compliance issue, not an architectural one." (stance)
  7. "Latency p50 = 180 ms, so we are fine." (metric report)
  8. "Modifiability matters, but we will focus on it after launch." (plan)

For each, name the specific failure: missing environment, missing measure, missing characteristic, confused pair, or wrong category.

Mini Application​

You have a one-page brief from the product team for a B2B IoT smart-building platform. Excerpts:

"The platform should support buildings with up to 50,000 connected devices. It should be easy to integrate new device vendors. Operations wants better visibility when devices go offline; today we only find out when tenants complain. Security is important - we had a penetration-test finding last year. Product wants to ship a feature every two weeks."

Produce:

  1. A list of at least 8 quality-attribute scenarios pulled from this brief, grouped under operational and evolutionary. Each scenario must have stimulus, environment, response, and measurable response.
  2. For each, one sentence naming who would measure it and the signal they would use.
  3. A short section at the bottom listing qualities the brief implies but does not state (availability during business hours, for example). State each implicit quality and why context makes it non-negotiable.
  4. A one-paragraph reflection: which three scenarios are the most important to nail down before architectural decisions, and why?

Constrain to two pages. If you cannot fit, you are probably duplicating qualities.

Evidence Check​

This page is complete only if, given a new brief from a stakeholder:

  • you can extract at least 8 candidate quality scenarios within 30 minutes
  • every scenario has a measurable response that a monitor or test could assert
  • you can distinguish operational from evolutionary qualities without thinking about it
  • you can name at least 3 implicit qualities the brief does not state but context demands
  • you can explain back to the stakeholder why "the system should be fast and reliable" is two different conversations, not one

Integrated Architecture Vocabulary Drill​

Trace a simple web application from browser to database.

  1. Label client, server, API, database, cache, queue, and third-party service if present.
  2. Name the architecture style you see: client/server, layered, modular monolith, service-based, event-driven, or hybrid.
  3. For each hop, name one quality attribute affected by the boundary.
  4. Write two style-selection prompts: one that would push the system toward a simpler modular design and one that would justify extracting a service.

Evidence check: include a diagram and a paragraph explaining why "web app" is not itself an architecture style.