# OTA diagrams

PlantUML sources accompany chapters 03–07. The diagrams describe the example A/B design, not a required platform or partition table.

| View | Source | Preview |
|---|---|---|
| Roles and the server/device boundary | [PlantUML](plantuml/ota-architecture.puml) | [PNG](rendered/ota-architecture.png) |
| Trial boot, confirmation and recovery | [PlantUML](plantuml/ab-trial-boot.puml) | [PNG](rendered/ab-trial-boot.png) |
| Storage areas and access responsibilities | [PlantUML](plantuml/ab-storage-layout.puml) | [PNG](rendered/ab-storage-layout.png) |
| Preparation and activation sequence | [PlantUML](plantuml/ab-installation-sequence.puml) | [PNG](rendered/ab-installation-sequence.png) |
| Installation states and restart decisions | [PlantUML](plantuml/ab-installation-recovery.puml) | [PNG](rendered/ab-installation-recovery.png) |
| Rollback eligibility and recovery decisions | [PlantUML](plantuml/rollback-policy.puml) | [PNG](rendered/rollback-policy.png) |
| Recovery coordination and restart | [PlantUML](plantuml/rollback-recovery-sequence.puml) | [PNG](rendered/rollback-recovery-sequence.png) |
| Rollback window and release lifecycle | [PlantUML](plantuml/rollback-window.puml) | [PNG](rendered/rollback-window.png) |

From the repository root, regenerate previews with a local PlantUML installation and Graphviz:

```sh
JAVA_TOOL_OPTIONS=-Djava.awt.headless=true plantuml -tpng -o ../rendered diagrams/plantuml/*.puml
```

Chapters 03–07 include PNG previews alongside their editable PlantUML sources. No external rendering service is needed. These diagrams do not establish power-loss safety. The [A/B simulation](../examples/simulations/ab-trial-boot/readme.md) covers trial boot. The [interrupted installation model](../examples/simulations/interrupted-installation/readme.md) covers preparation, old progress, and supplied boot-record write outcomes. The [rollback policy simulation](../examples/simulations/rollback-policy/readme.md) covers recovery eligibility, data loss, bounded attempts, and failed-release blocks.