Reclaim edge-journal pages only after durable delivery acknowledgements
The gateway erases a page after sending bytes, before the receiver acknowledges them. Gate reclamation on durable acknowledgements.
- Focused work estimate
- 3h + prerequisites
- Priority in the scenario
- High
- Engineering practice
- Delivery semantics · Storage
Estimated field mix
- Storage systems40%
- Embedded and edge30%
- Distributed systems30%
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
- CJOUR-106 · Roll edge-journal writes onto a new page without overwriting unread events
- CJOUR-107 · Recover edge-journal page generation selection after power loss
Acceptance criteria
- Sent-only records remain protected
- Acknowledged complete page may erase
- Crash before acknowledgement persistence keeps page
Implementation constraints
- Receiver stub must support replay by stable event identity.
Verification to include
- Acknowledge all page records
- Timeout after receiver acceptance
Deliverables
- Ack ledger and reclamation cases
Rollout and recovery
Pause erasure if acknowledgement state is uncertain.
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.