systems-architect

# Skill: Systems Architect The Systems Architect works at **system scope**: a whole system in engineering terms — hardware, software, human and environment — beyond pure software. Where the software architect owns code structure, the systems architect owns the decomposition, interfaces and lifecycle integrity of the system as a whole. --- ## 1. When This Skill Applies - Decomposing a system into subsystems and components and defining their interfaces. - Owning high-level requirements and acceptance criteria. - Performing cost/benefit and trade-off analysis across technologies. - Layering and partitioning the architecture for comprehensibility. - Maintaining architectural integrity through the system lifecycle. Does NOT apply to: pure software structure (use [software-architect](../../../roles/software-architect/SKILL.md)), or one solution's design (use [solution-architect](../../enterprise/solution-architect/SKILL.md)). --- ## 2. What Makes Systems Scope Different | Software scope | Systems scope | |---|---| | Modules, classes, packages | Subsystems, hardware, humans, environment | | Code-level interfaces | Physical and logical interfaces | | Software quality attributes | Safety, reliability, maintainability, cost | | Build/test pipeline | Full lifecycle: requirements to disposal | --- ## 3. Method 1. **Elicit** stakeholders, concerns and the system boundary. 2. **Decompose** into subsystems and define interfaces between them. 3. **Allocate** requirements to subsystems and define acceptance criteria. 4. **Analyse** trade-offs (cost, performance, risk, schedule). 5. **Maintain** architectural integrity as the system evolves. 6. **Describe** the architecture with viewpoints conforming to the architecture-description standard. --- ## 4. Orchestration and Handoffs | Concern | Owning skill | |---|---| | Enterprise frame and standards | [enterprise-architect](../../enterprise/enterprise-architect/SKILL.md) | | Software structure and patterns | [software-architect](../../../roles/software-architect/SKILL.md) | | Embedded/IoT and real-time constraints | [hardware-hacking-embedded-security](../../../domains/industry/hardware-hacking-embedded-security/SKILL.md) | | Architecture description standard | [c4-model-architecture](../../../engineering/practices/c4-model-architecture/SKILL.md) | | Microprocessor and embedded architecture | [academic-microprocessors-embedded-systems](../../../domains/academic/academic-microprocessors-embedded-systems/SKILL.md) | | Reliability and scalability | [system-design-scalability](../../../engineering/practices/system-design-scalability/SKILL.md) | | Safety constraints (functional safety) | resolve the applicable standard before citing | --- ## 5. Reference Frameworks - **ISO/IEC/IEEE 42010** — the architecture-description standard, explicitly scoped to software, systems and enterprise. - **Systems engineering handbook** — the INCOSE body of knowledge (resolve the edition before citing). - **Systems architecting texts** — the classic systems-architecting literature. - **SAFe** — the System Architect role at one Agile Release Train's scope. See [ea-frameworks](../../enterprise/enterprise-architect/references/ea-frameworks.md). --- ## 6. Common Mistakes | Mistake | Correction | |---|---| | Treating a system as software only | Include hardware, human and environment | | Interfaces left implicit | Every interface is defined and owned | | No requirement allocation | Allocate requirements to subsystems | | Ignoring non-technical trade-offs | Cost, schedule and risk are architectural | | Using a description format that violates the standard | Conform to the architecture-description standard |