## Chapter 12 — Three nodes stay the vendor's ### Lesson map Lesson 12. Map, example, EX058. ```mermaid flowchart TD A["Points service creates the points"] --> B["Three nodes keep the record"] B --> C["Both are the vendor's"] C --> D{"Does Copperleaf run a node?"} D -->|No| E["Leave the map at three vendor nodes"] ``` Concentration is the fact the map was drawn to show. ### Logical drawing ```text six parts app wallets, café tills, points service points contract, three nodes, customer database who runs the nodes the vendor, all three who does not Copperleaf a fourth node that is not on the map ``` ### Learning outcomes After this chapter, you should be able to: 1. Name who runs the three nodes. 2. Keep point creation and the nodes with the same company. 3. Refuse a fourth node or a Copperleaf-run node. ### 12.1 The map concentrates two powers. Chapter 3 draws six parts: customers' app wallets, the café tills, the vendor's points service, the points contract, three ledger nodes, and Copperleaf's customer database. The points service converts purchases into awards and decides how many points are created. The nodes keep the shared append-only record. The vendor runs all three nodes. Copperleaf runs none. One company therefore controls both the creation of points and every copy of the record the map contains. That concentration is the worry Elena names. A later note might try to soften it by saying Copperleaf operates a node, or by adding a fourth node at another firm. Neither sentence has support. The manuscript does not split the three nodes across companies, and it does not add a node. The customer database is Copperleaf's part of the map, and a database is not a ledger node. Leaving the nodes with the vendor is not an insult and not a comfort. It is the arrangement the pilot would still have to live with, including the exit questions the next lesson keeps open. ### 12.2 Worked example Count the nodes from the map, then name their operator. | Statement | Map | Decision | |---|---|---| | "The vendor runs three nodes." | Chapter 3 | May stay | | "The points service decides how many points are created." | The same map | May stay | | "Copperleaf runs one of the nodes." | Copperleaf runs the database, not a node | Refuse | | "A fourth node was added." | No fourth node | Refuse | > **Synthetic case.** The nodes are parts of a fictional test ledger. No operator is a real company. ### Errors and limits Drawing the concentration does not remove it. The pilot conditions do not redraw the map. ### Apply - **EX058 — Who keeps the record?** A slide says Copperleaf now runs a node and that a fourth node shares the load. What does the map actually say? *Rubric:* 3 = the vendor still runs all three nodes; Copperleaf does not run a node; no fourth node is added; point creation stays with the vendor's service;; 2 = three vendor nodes and no Copperleaf node;; 1 = the vendor only;; 0 = none. ### Continue studying — lesson 12 (chapter 12 of 20) [← Chapter 11](#ch-11) · [Course chapter index](../SUBJECTS.md) · [Chapter 13 →](#ch-13) Continue to the next authored lesson. ## Worked answers **EX058.** The vendor still runs all three nodes. Copperleaf does not run a node. Do not add a fourth.