Working notes on the engineering concepts a programme and portfolio manager actually needs: enough depth to referee architecture conversations, challenge vendor SLA claims, and ask the question the room is avoiding. Not interview prep for engineers. Field notes for delivery leaders.
Written and maintained by a delivery manager with 20+ years across UK financial services, who got tired of nodding through architecture reviews.
| Note | Why a delivery manager cares |
|---|---|
| Availability, nines, and SLAs | What 99.9% actually costs in downtime, and why chaining three 99.9% vendors never gives you 99.9% |
| The trade-offs engineers argue about | Performance vs scalability, latency vs throughput, CAP. The vocabulary of every architecture disagreement |
| Queues, async, and back pressure | Why systems and teams fail the same way when work arrives faster than it drains |
| Architecture patterns in one page | Six patterns, what each buys you, what each costs you, and what to ask when a team proposes one |
Delivery managers don't need to design systems. They need to know when an estimate is optimistic, when an SLA is arithmetic fiction, and when "we'll just add a queue" is hiding an unsolved problem. These notes target exactly that layer.
Sources include The System Design Primer and field experience. Mistakes are mine; corrections welcome via issues.