Quiz

2627 questions of the kind that actually get asked — in interviews, in architecture review boards, and by the person who has to run the thing at 3 AM. Every answer states the trade-off rather than the slogan, and says when the obvious choice is the wrong one.

All areas2627 Architecture Fundamentals81 Distributed Systems101 Data Architecture90 Cloud Architecture77 Networking86 API & Integration Architecture78 Reliability & Resilience88 Observability81 Performance & Capacity Engineering90 Security Architecture85 Cost Architecture & FinOps82 Business Architecture93 Architecture Communication91 Enterprise Architecture91 Legacy Modernization82 AI-Era Architecture86 Software Architecture & Engineering84 Architecture Patterns84 Architecture Decision-Making91 The Architect's Meta-Skills92 Delivery & Release Engineering93 Platform Engineering & Developer Experience92 Testing & Quality Architecture90 Data Platform Architecture88 Streaming & Real-Time Data93 Data Governance & Semantics81 Frontend & Experience Architecture91 Edge, Mobile & IoT88 Regulatory & Data Protection Architecture90 Assurance, Audit & Model Risk88

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82 questions in Legacy Modernization.

Quiz

A replaced system was made read-only for 30 days. No complaints came in and it was switched off, with its data exported to an archive. Three weeks later the annual regulatory extract fails, because the job read directly from the retired database. Which design decision made this possible?

A team inherits a system nobody fully understands and is asked whether to rewrite it. What should be established before answering?

A twenty-year-old core system supports most of the business. It is on unsupported technology, three people understand it, and the last replacement attempt was abandoned after two years. Design the programme.

Before modernising, a team must assess a legacy system. What should the assessment measure, and what is usually skipped?

On Salesforce's Force.com platform, a customer's custom objects and fields are rows of metadata in shared tables rather than a schema of their own (Weissman and Bobrowski described the design at SIGMOD in 2009). What does that remove from the legacy problem, and what does it not remove?

A fourteen-year-old policy system sustains roughly 350 transactions per second at its measured peak and the business peak already consumes about 260 of them. Four new services want to call it directly. Roughly how much of that system can you sell them, and what does the number decide?

A new notifications service needs customer contact data that only a twelve-year-old billing system holds. The team points it at a read replica of the billing database and ships in a week. Why does this work, and why is it still the most expensive integration they could have chosen?

A new platform must integrate with legacy systems that only support batch file exchange. How should the boundary be designed so the new system is not constrained by it?

New services must interact with a legacy system that cannot handle their load or their pace of change. Which integration patterns apply?

A 15-year-old monolith runs the core of the business. Leadership wants microservices. How do you approach it, and what would make you refuse?

Most large modernisation programmes are late, over budget, or abandoned. What are the recurring structural causes, rather than the project-management ones?

TSB's 2018 core banking migration moved 1.9 million customers in a single weekend and failed publicly. What would you have required before approving that cutover?