# noCV engineering task library Content version 5 Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Tests, patches, and runbooks are requested deliverables. They become Outcome Evidence only through a qualified Mission and immutable Evidence IDs. Independent adaptation must be observed under a declared verification policy and cite immutable Evidence IDs. Completing a planning ticket establishes no Ownership Evidence. ## CJOUR — A power-loss-tolerant edge event journal 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. **Field:** Embedded and edge. **Suggested stack:** TypeScript, Flash-storage emulator, Vitest. **Engineer value:** Practice torn writes, wear-aware batching and acknowledged durability. **Company value:** Inspect whether offline device records remain recoverable within stated constraints. **Delivery agreement:** Emulator guarantees are explicit; real flash endurance and device qualification remain separate. ### Setup prerequisites - Specify emulator page size write rules and erase behavior. - Generate synthetic records and deterministic power-cut schedules. ### Define durable records Encode and validate journal entries. #### CJOUR-101 — Model edge-journal flash writes with explicit emulator constraints **Task · Medium priority · Foundational** noCV practice brief v5 · CJOUR-101 · A power-loss-tolerant edge event journal Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Define durable records. Depends on: No preceding ticket. Difficulty: Foundational. Estimated focused work: 90 minutes; setup and prerequisite tickets are additional. Estimated field mix: Embedded and edge 60% · Storage systems 40%. Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence. The byte-array stub permits writes that real flash-like storage would reject. Declare and enforce the chosen emulator model. Acceptance criteria - Page boundaries are explicit - Forbidden bit transitions fail - Erase resets one selected page Implementation constraints - This models selected behavior and does not certify real hardware. Verification - Write allowed transition - Attempt forbidden transition without erase Deliverables - Flash emulator contract and cases Rollout and recovery: Stop journal writes when adapter behavior violates the declared model. Project prerequisites: Specify emulator page size write rules and erase behavior. Generate synthetic records and deterministic power-cut schedules. Engineer value: Practice torn writes, wear-aware batching and acknowledged durability. Company value: Inspect whether offline device records remain recoverable within stated constraints. AI tools are welcome during implementation. Record assumptions, review the result, and verify its behavior. Planning status does not create Outcome Evidence or Ownership Evidence. #### CJOUR-102 — Encode edge-journal records with bounded length and checksum **Task · High priority · Foundational** noCV practice brief v5 · CJOUR-102 · A power-loss-tolerant edge event journal Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Define durable records. Depends on: CJOUR-101. Difficulty: Foundational. Estimated focused work: 90 minutes; setup and prerequisite tickets are additional. Estimated field mix: Embedded and edge 50% · Storage systems 50%. Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence. Truncated synthetic records are indistinguishable from valid short payloads. Add explicit length and integrity fields. Acceptance criteria - Payload bytes round-trip - Length is bounded - Checksum mismatch rejects record Implementation constraints - Checksum is corruption detection, not authentication. Verification - Encode valid record - Flip one stored byte Deliverables - Record codec and corruption cases Rollout and recovery: Keep affected pages read-only for inspection. Project prerequisites: Specify emulator page size write rules and erase behavior. Generate synthetic records and deterministic power-cut schedules. Engineer value: Practice torn writes, wear-aware batching and acknowledged durability. Company value: Inspect whether offline device records remain recoverable within stated constraints. AI tools are welcome during implementation. Record assumptions, review the result, and verify its behavior. Planning status does not create Outcome Evidence or Ownership Evidence. #### CJOUR-103 — Assign edge-journal event identities independently from delivery attempts **Bug · Medium priority · Intermediate** noCV practice brief v5 · CJOUR-103 · A power-loss-tolerant edge event journal Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Define durable records. Depends on: CJOUR-102. Difficulty: Intermediate. Estimated focused work: 105 minutes; setup and prerequisite tickets are additional. Estimated field mix: Embedded and edge 50% · Distributed systems 30% · Storage systems 20%. Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence. Retried uploads mint new event IDs and duplicate accepted readings. Persist identity with the original record. Acceptance criteria - Retry preserves identity - New records get distinct identity - Restart retains stored identity Implementation constraints - IDs must not encode raw reading values. Verification - Retry same record - Restart and compare identities Deliverables - Event identity contract and cases Rollout and recovery: Pause replay if stored identity cannot be recovered. Project prerequisites: Specify emulator page size write rules and erase behavior. Generate synthetic records and deterministic power-cut schedules. Engineer value: Practice torn writes, wear-aware batching and acknowledged durability. Company value: Inspect whether offline device records remain recoverable within stated constraints. AI tools are welcome during implementation. Record assumptions, review the result, and verify its behavior. Planning status does not create Outcome Evidence or Ownership Evidence. ### Recover interrupted writes Handle commits and page boundaries. #### CJOUR-104 — Commit edge-journal records only after their marker is durable **Task · High priority · Advanced** noCV practice brief v5 · CJOUR-104 · A power-loss-tolerant edge event journal Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Recover interrupted writes. Depends on: CJOUR-102, CJOUR-103. Difficulty: Advanced. Estimated focused work: 180 minutes; setup and prerequisite tickets are additional. Estimated field mix: Storage systems 60% · Embedded and edge 40%. Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence. A record appears readable before its body finishes writing. Introduce a commit-marker protocol compatible with the emulator. Acceptance criteria - Uncommitted bodies stay invisible - Acknowledgement follows durable marker - Invalid marker cannot authorize partial body Implementation constraints - Specify write and flush ordering explicitly. Verification - Write committed fixture - Cut power before marker Deliverables - Commit protocol and cut-point tests Rollout and recovery: Disable acknowledgement if the durability barrier fails. Project prerequisites: Specify emulator page size write rules and erase behavior. Generate synthetic records and deterministic power-cut schedules. Engineer value: Practice torn writes, wear-aware batching and acknowledged durability. Company value: Inspect whether offline device records remain recoverable within stated constraints. AI tools are welcome during implementation. Record assumptions, review the result, and verify its behavior. Planning status does not create Outcome Evidence or Ownership Evidence. #### CJOUR-105 — Recover edge-journal scanning after a torn final record **Bug · High priority · Advanced** noCV practice brief v5 · CJOUR-105 · A power-loss-tolerant edge event journal Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Recover interrupted writes. Depends on: CJOUR-104. Difficulty: Advanced. Estimated focused work: 180 minutes; setup and prerequisite tickets are additional. Estimated field mix: Storage systems 60% · Embedded and edge 40%. Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence. Startup stops at partial data and loses earlier committed events. Scan the valid committed prefix conservatively. Acceptance criteria - Earlier committed records survive - Incomplete tail is ignored with reason - Middle corruption is not silently skipped Implementation constraints - Preserve damaged bytes for explicit local diagnosis. Verification - Cut final body write - Corrupt an earlier committed record Deliverables - Recovery scanner and fault cases Rollout and recovery: Open journal read-only when corruption is not a tail interruption. Project prerequisites: Specify emulator page size write rules and erase behavior. Generate synthetic records and deterministic power-cut schedules. Engineer value: Practice torn writes, wear-aware batching and acknowledged durability. Company value: Inspect whether offline device records remain recoverable within stated constraints. AI tools are welcome during implementation. Record assumptions, review the result, and verify its behavior. Planning status does not create Outcome Evidence or Ownership Evidence. #### CJOUR-106 — Roll edge-journal writes onto a new page without overwriting unread events **Task · High priority · Intermediate** noCV practice brief v5 · CJOUR-106 · A power-loss-tolerant edge event journal Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Recover interrupted writes. Depends on: CJOUR-101, CJOUR-104, CJOUR-105. Difficulty: Intermediate. Estimated focused work: 135 minutes; setup and prerequisite tickets are additional. Estimated field mix: Embedded and edge 50% · Storage systems 50%. Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence. Page wrap overwrites unacknowledged events. Separate writable capacity from reclaimable pages. 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 - 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. Project prerequisites: Specify emulator page size write rules and erase behavior. Generate synthetic records and deterministic power-cut schedules. Engineer value: Practice torn writes, wear-aware batching and acknowledged durability. Company value: Inspect whether offline device records remain recoverable within stated constraints. AI tools are welcome during implementation. Record assumptions, review the result, and verify its behavior. Planning status does not create Outcome Evidence or Ownership Evidence. #### CJOUR-107 — Recover edge-journal page generation selection after power loss **Bug · High priority · Expert** noCV practice brief v5 · CJOUR-107 · A power-loss-tolerant edge event journal Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Recover interrupted writes. Depends on: CJOUR-105, CJOUR-106. Difficulty: Expert. Estimated focused work: 240 minutes; setup and prerequisite tickets are additional. Estimated field mix: Storage systems 60% · Embedded and edge 40%. Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence. A cut during page-header activation leaves two pages claiming to be newest. Resolve generations through a declared ordering rule. Acceptance criteria - Recovery chooses valid committed generation - Incomplete header cannot supersede valid page - Ambiguous generations fail visibly Implementation constraints - Include wrap behavior in generation comparison. Verification - Cut header activation - Exercise generation wrap fixture Deliverables - Generation selection and boundary tests Rollout and recovery: Preserve both pages and stop writes on unresolved ambiguity. Project prerequisites: Specify emulator page size write rules and erase behavior. Generate synthetic records and deterministic power-cut schedules. Engineer value: Practice torn writes, wear-aware batching and acknowledged durability. Company value: Inspect whether offline device records remain recoverable within stated constraints. AI tools are welcome during implementation. Record assumptions, review the result, and verify its behavior. Planning status does not create Outcome Evidence or Ownership Evidence. ### Manage finite storage Reclaim acknowledged records safely. #### CJOUR-108 — Reclaim edge-journal pages only after durable delivery acknowledgements **Task · High priority · Advanced** noCV practice brief v5 · CJOUR-108 · A power-loss-tolerant edge event journal Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Manage finite storage. Depends on: CJOUR-103, CJOUR-107. Difficulty: Advanced. Estimated focused work: 180 minutes; setup and prerequisite tickets are additional. Estimated field mix: Storage systems 40% · Embedded and edge 30% · Distributed systems 30%. Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence. The gateway erases a page after sending bytes, before the receiver acknowledges them. Gate reclamation on durable acknowledgements. 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 - Acknowledge all page records - Timeout after receiver acceptance Deliverables - Ack ledger and reclamation cases Rollout and recovery: Pause erasure if acknowledgement state is uncertain. Project prerequisites: Specify emulator page size write rules and erase behavior. Generate synthetic records and deterministic power-cut schedules. Engineer value: Practice torn writes, wear-aware batching and acknowledged durability. Company value: Inspect whether offline device records remain recoverable within stated constraints. AI tools are welcome during implementation. Record assumptions, review the result, and verify its behavior. Planning status does not create Outcome Evidence or Ownership Evidence. #### CJOUR-109 — Batch edge-journal metadata updates within a declared loss window **Chore · Medium priority · Advanced** noCV practice brief v5 · CJOUR-109 · A power-loss-tolerant edge event journal Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Manage finite storage. Depends on: CJOUR-108. Difficulty: Advanced. Estimated focused work: 165 minutes; setup and prerequisite tickets are additional. Estimated field mix: Performance engineering 40% · Storage systems 30% · Embedded and edge 30%. Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence. A metadata write for every status poll causes unnecessary emulated erase work. Batch only nonauthoritative counters. Acceptance criteria - Event commits remain durable - Batching does not weaken acknowledgement protection - Counter loss window is documented Implementation constraints - Do not batch safety-critical authority or claim real endurance improvement. Verification - Compare emulator operation counts - Cut power before counter flush Deliverables - Counter batching and measured local trace Rollout and recovery: Disable batching if authority depends on buffered counters. Project prerequisites: Specify emulator page size write rules and erase behavior. Generate synthetic records and deterministic power-cut schedules. Engineer value: Practice torn writes, wear-aware batching and acknowledged durability. Company value: Inspect whether offline device records remain recoverable within stated constraints. AI tools are welcome during implementation. Record assumptions, review the result, and verify its behavior. Planning status does not create Outcome Evidence or Ownership Evidence. #### CJOUR-110 — Inspect edge-journal pages without modifying recovery state **Story · Medium priority · Intermediate** noCV practice brief v5 · CJOUR-110 · A power-loss-tolerant edge event journal Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Manage finite storage. Depends on: CJOUR-107, CJOUR-109. Difficulty: Intermediate. Estimated focused work: 120 minutes; setup and prerequisite tickets are additional. Estimated field mix: Developer tooling 40% · Embedded and edge 30% · Storage systems 30%. Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence. Debugging currently boots the journal and may erase pages. Add a read-only page inspector. Acceptance criteria - Reports generation and commit validity - Does not erase or rewrite - Payload display is opt-in Implementation constraints - Restrict input to explicit synthetic image files. Verification - Inspect valid image - Inspect torn and corrupt images Deliverables - Inspector and no-write assertions Rollout and recovery: Keep diagnostic mode read-only if recovery suggestions are uncertain. Project prerequisites: Specify emulator page size write rules and erase behavior. Generate synthetic records and deterministic power-cut schedules. Engineer value: Practice torn writes, wear-aware batching and acknowledged durability. Company value: Inspect whether offline device records remain recoverable within stated constraints. AI tools are welcome during implementation. Record assumptions, review the result, and verify its behavior. Planning status does not create Outcome Evidence or Ownership Evidence.