SR-02 · our practice ref · series-structure

Define the system architecture

Practice SR-02 in the System Definition and Realisation group. The basis is series-structure, and the row asks for 3 pieces of evidence.

At a glance

Ref: SR-02
Process: System Definition and Realisation
Basis: series-structure
Source: Public abstract, process list
Evidence: 3 items
Gaps: 2 common

Evidence to keep

System Definition and RealisationThe architecture description with elements and interfaces
System Definition and RealisationThe element table with responsibilities
System Definition and RealisationThe decision record for make or buy

Questions before you sign

What are the elements, and what does each own?
Which interfaces carry the most risk?
Which elements will we acquire?

The practice, in our words

Describe the system as elements, their responsibilities and their interfaces. The architecture is the bridge between the requirements and the work of building, and it is where the team decides what it will buy and what it will make.

What it means in a VSE

One diagram and one element table are enough to start. Name each element, say what it must do, and list its interfaces with the element on the other side. Mark the elements that will be acquired, because those carry acquisition evidence.

In a firm of 25 people or fewer, define the system architecture has to earn its time. The test for SR-02 is not whether the team understands it but whether the artefact exists at the end of the project. Shrink the meeting. Shrink the document. Keep the record.

How to evidence it

Attach the artefacts above to the Define the system architecture row with the project name, the owner and the date. The anchor for SR-02 is The architecture description with elements and interfaces. A named person must produce it on request.

For SR-02, the reviewer will sample one live decision and ask for The element table with responsibilities. No artefact, no evidence. A file that depends on one person's mailbox is not a file for define the system architecture.

What an assessor samples

An assessor reads the define the system architecture practice, asks for its evidence and tests one project against it. For SR-02, the useful sample is the most recent project that used the practice, not the best one. A reconstruction written for the visit is a finding for SR-02 if the practice cannot be shown to have happened when it mattered.

Common gaps

An architecture that exists only in the lead engineer's head
Interfaces left to be discovered during integration

What changes from the 2019 report. For SR-02, system definition and realisation holds most of the evidence. The transition work is to keep the record as the work proceeds, not to reconstruct it at the end.

Where the draft fits

The public abstract places define the system architecture inside one of the four processes the Intermediate profile covers. For SR-02, the draft clause numbering and wording are not public, so this page cites Public abstract, process list and does not quote the draft. The basis label for SR-02 says whether the practice is stated in the public record, named as a process in the series, or our reading.

Related practices

Source for this page: Public abstract, process list. Open the record and compare it with the SR-02 statement above. Retrieved 2026-10-22.