If all of these items are documented and/or diagrammed, if it's done thoroughly and accurately, they will, collectively, provide a holistic view of the total scope of a system:
- Every system component role should be identified in the Logical Architecture
- Where each of those components actually resides should be identified in the Physical Architecture
- Every use case (and hopefully every business process) that the system is supposed to implement should be identified in the use-case documentation, and any of the underlying processes that aren't painfully obvious should have at least a rough happy-path breakdown
- Every chunk of data that moves from one place or process to another should be identified in the Data Flow, with enough detail to collate a fairly complete picture of the structure of that data as well
- The formats and protocols that govern...