Roll edge-journal writes onto a new page without overwriting unread events
Page wrap overwrites unacknowledged events. Separate writable capacity from reclaimable pages.
- Focused work estimate
- 2h 15m + prerequisites
- Priority in the scenario
- High
- Engineering practice
- Ring buffers · Resource limits
Estimated field mix
- Embedded and edge50%
- Storage systems50%
Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence.
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Project context
Fictional edge display gateway stores noncritical synthetic readings while disconnected. Implement a byte-array flash emulator with explicit erase/write behavior and injected power cuts; no physical storage device is required.
Setup prerequisites
- Specify emulator page size write rules and erase behavior.
- Generate synthetic records and deterministic power-cut schedules.
Preceding work
Complete these dependencies, or supply their agreed outputs before taking this ticket.
- CJOUR-101 · Model edge-journal flash writes with explicit emulator constraints
- CJOUR-102 · Encode edge-journal records with bounded length and checksum
- CJOUR-103 · Assign edge-journal event identities independently from delivery attempts
- CJOUR-104 · Commit edge-journal records only after their marker is durable
- CJOUR-105 · Recover edge-journal scanning after a torn final record
Acceptance criteria
- Active unread pages remain protected
- Full journal returns explicit capacity result
- New page starts with validated header
Implementation constraints
- Do not silently discard oldest readings.
Verification to include
- Fill to page boundary
- Fill entire journal without acknowledgements
Deliverables
- Page allocator and full-capacity cases
Rollout and recovery
Stop admission when no safe writable page exists.
Value of the work
For the engineer: Practice torn writes, wear-aware batching and acknowledged durability.
For the team: Inspect whether offline device records remain recoverable within stated constraints.
Evidence boundaries
Outcome Evidence: Tests, patches, and runbooks are requested deliverables. They become Outcome Evidence only through a qualified Mission and immutable Evidence IDs.
Ownership Evidence: Independent adaptation must be observed under a declared verification policy and cite immutable Evidence IDs. Completing a planning ticket establishes no Ownership Evidence.