ASSIGNMENT 8 · CHAPTER 17
Reason about a lost remote response
Use the familiar decision-and-evidence sequence. This chapter focuses on architecture → failure sequence → recovery evidence. Make the initial decision before seeing the new evidence.
- Warm-up
- FIT → FAILURE → BOUND → ACT + EVIDENCE
- Commit Part A
- STRESS → REFIT
- AI declaration + human review
- Export and submit in LMS
1 · WARM-UP · 5 MINUTES · NOT GRADED
A remote payment call times out. Can the caller safely assume the payment did not happen?
Show / hide warm-up answer
No. The server may have executed the request before the response was lost. Retrying needs a defined identity, deduplication or reconciliation mechanism.
No written warm-up response is required.
Lecture guide
X02A, X03, X05, R09 and X09; original slides 14–28 and 53–64. Retry-specific reasoning is a labelled course application.
FIT identifies the relevant problem. FAILURE builds this chapter’s artifact. BOUND states the limits. ACT + EVIDENCE records the action, owner and verification. STRESS then tests your reasoning before REFIT.
READ BEFORE ANSWERING
How your work is assessed · 5 points
| Criterion | Scoring |
|---|---|
| FIT · 1 point | 1: Defines the chapter-specific problem accurately, distinguishes facts from assumptions and connects it to the proposed action. 0.75: Sound reasoning with one minor omission. 0.5: Partly correct, with a consequential gap. 0: Missing, materially incorrect or based on invented evidence. |
| FAILURE · 1 point | 1: A causally correct failure sequence, justified retry or reconciliation rule, and a test that distinguishes one committed action from duplicate actions. 0.75: Sound reasoning with one minor omission. 0.5: Partly correct, with a consequential gap. 0: Missing, materially incorrect or based on invented evidence. |
| BOUND · 1 point | 1: States relevant operating assumptions, scope and an observable trigger to reconsider the claim. 0.75: Sound reasoning with one minor omission. 0.5: Partly correct, with a consequential gap. 0: Missing, materially incorrect or based on invented evidence. |
| ACT + EVIDENCE · 1 point | 1: Gives a feasible bounded action, named responsibility and inspectable evidence, while distinguishing completed from proposed verification. 0.75: Sound reasoning with one minor omission. 0.5: Partly correct, with a consequential gap. 0: Missing, materially incorrect or based on invented evidence. |
| REFIT · 1 point | 1: Explains how the new evidence affects the initial claim and justifies RETAIN, REVISE or REPLACE with a coherent final record. 0.75: Sound reasoning with one minor omission. 0.5: Partly correct, with a consequential gap. 0: Missing, materially incorrect or based on invented evidence. |
Five points use the same familiar structure. The chapter artifact changes; the LMS determines how assignment points contribute to the course grade.
Learning-outcome alignment
This task supports supplied syllabus CLO 9. It practises disciplinary knowledge, engineering skills and accountable decisions. It is course-written practice, not an official national readiness assessment or an approved item-weight mapping.
Before you start
Use Save draft while working and Download draft / backup before leaving a shared device. Part A becomes read-only only after you confirm commitment. You can continue editing Part B afterward.
The new evidence opens automatically after you commit Part A. No unlock code is required. Your initial reasoning stays saved and read-only. The sequence is designed to preserve your first judgment; it is not a secure examination system.
Identity
Loaded from the entry page. Drafts are separated by Student ID in this browser.
Submission details
Check the current deadline and submission instructions in the LMS.
2 · PART A · 20 MINUTES
Assessed scenario · fictional teaching case
A fictional event-registration system uses a browser, an application service and a booking database. The browser sends a reservation request through the service. When the request times out, the browser automatically retries with a new request identifier. The database creates one reservation per new identifier. The brief confirms that normal requests succeed, but contains no test where the response is lost after a database commit. You recommend a pilot architecture and retry policy.
Aim for 300–450 focused words overall. Use a small table or clear notation for the chapter artifact. No code or external experiment is required. Cite at least one relevant Chapter 17 unit/title or source page supporting your artifact and mechanism.
A1 · FIT · 1 POINT
Map the logical responsibilities to deployment tiers. Identify the remote boundary and distinguish failure to receive a response from failure to execute.
A2 · FAILURE · 1 POINT
Write a short event sequence for the lost-response case. Propose a retry/reconciliation rule and a test that would reveal duplicate reservations. State what remains an assumption.
A3 · BOUND · 1 POINT
State the failure modes and consistency requirement your recommendation covers. Identify the limit of the supplied tests.
A4 · ACT + EVIDENCE · 1 POINT
Recommend a bounded pilot action and an owner. Explain the mechanism and the evidence required before accepting automatic retries.
Name the relevant test/log/audit, the conditions it must cover, who checks it, and what evidence is still missing. Do not describe requested evidence as if it already exists.
Commit is not LMS submission. Confirmation freezes FIT, FAILURE, BOUND, ACT and EVIDENCE before the new information appears.