Session 4.1 - Design Principles & Purpose
Chapter 7: Designing with Teams | Duration: 1 hr
Learning Objectives
By the end of this session, you will be able to:
- Explain why TSPi emphasizes high-level design before coding
- Describe core design principles from Chapter 7
- Differentiate high-level, detailed design, and implementation
- Connect strategy outputs to the design phase
Introduction
Design provides the precise blueprint for building software. Chapter 7 stresses process and principles, not transient methods, because techniques evolve. A strong design prevents integration drag and late surprises.
Design Principles (Chapter 7)
- Design must produce a complete, precise specification—more than general ideas.
- Define principal parts, their interactions, and how they assemble into the system.
- High-level design enables parallel work without misfits at integration.
- Precise designs cut rework and schedule overrun.
Precision & Completeness
Vague designs push decisions to detail designers and coders, creating inconsistent choices that surface only in integration/system test. Precise designs include:
- Functional specs for each component
- Interfaces and state behavior
- Logical structure, loops, state transitions (for detailed design)
Design Levels in TSPi
From Strategy to Design
Strategy gave conceptual decomposition for planning. Design turns that into precise component specs and interfaces so multiple engineers can build independently and integrate cleanly.
Summary
- Design is about precise, complete specs—not just ideas.
- High-level design prevents integration pain by aligning components early.
- TSPi flows: conceptual (strategy) → high-level (DES1/DESn) → detailed (IMP1/IMPn).
- Use design to enable parallel work with minimal rework.