ASSIGNMENT 5 · CHAPTER 14
Keep one critical service running
Read the named source pages, check the five objectives, apply the concepts, then reassess your decision when new evidence appears. The total-time estimate includes preparation; report your actual time.
Practical hour. This build is this chapter’s practical hour. The assignment is not submitted without it. Running the tests is a separate row in the rubric; longer writing does not make up for it.
الساعة التطبيقية. هذا البناء هو الساعة التطبيقية لهذا الفصل. لا يُسلَّم الواجب بدونه. تشغيل الاختبارات صف مستقل في السلّم، لا يُعوَّض بطول الكتابة.
Course learning outcome 6: Design systems to support resilience, practised by building and testing the reconciliation. The tests and the coverage step practise outcome 11: design and implement test cases across testing strategies.
مخرج التعلم 6: تصميم الأنظمة لدعم الصمود، ويُمارَس ببناء المطابقة بعد التعافي واختباره. والاختبارات وخطوة التغطية تمارس المخرج 11: تصميم حالات الاختبار وتنفيذها.
- Warm-up
- FIT → RECOVER → 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 backup server starts successfully. Does that mean staff can carry out the essential service again?
Show / hide warm-up answer
No. Check whether the data is recent enough, staff can access it, other required services work, and staff can finish the task. A running server alone does not show this.
Lecture guide
X02, X04, D14, X06 and B01; original slides 6–17 and 28–61.
FIT identifies the relevant problem. RECOVER builds this chapter’s artifact. BOUND states the limits. ACT + EVIDENCE records the action, owner and verification. STRESS then tests your reasoning before REFIT.
Chapter map · Relevant mechanism · 20-rule map · Practice card. Source and chapter-unit identifiers are not canonical rule numbers.
CURRENT EDITION · MASTERY V2
Required preparation and assessment scope
Read: Sociotechnical and organizational resilience: slides 18–23; Survivability analysis: slides 42–45.
Complete the five-objective preparation check after the assigned reading before you start.
Scope notes and earlier editions
Blackboard supplies the calendar deadline. All five chapter objectives, the classroom concepts and named reading are in assessment scope. Optional toolkit activities are enrichment unless assigned.
One assigned source application and one short transfer answer are included below, within the existing 5-point rubric. A reading click or a practice score is not proof of mastery.
Already started the previous edition? Resume or export your previous work using the same ID and browser. Previous drafts stay separate. Completed submissions do not need repeating unless the instructor requests it.
READ BEFORE ANSWERING
How your work is assessed · 5 points
| Criterion | Scoring |
|---|---|
| FIT · 1 point | 1: Defines the problem using the chapter ideas accurately, distinguishes facts from assumptions and connects it to the proposed action. The short answer applying a second chapter idea must correctly apply the second concept; FIT and that answer together earn this single point.Partial credit: 0.75 · 0.5 · 00.75: The right concept and mechanism, but one link is thin: a fact and an assumption are not separated, or the transfer answer applies the second concept only partly.0.5: A relevant concept is named but applied generically or to the wrong mechanism, or the transfer answer is missing or incorrect. 0: No chapter concept is applied, the case is misread, or the answer depends on invented facts. A generic “hold and test” statement does not satisfy this criterion. |
| RECOVER · 1 point | 1: A coherent response across the four resilience activities, including usable degraded service, reconciliation and a testable recovery check. Apply one idea from the assigned reading to your technical work and explain the connection. Build: every course check passes, your own tests catch every known bug (mutation test), and you can make your code change for the short discussion (micro-viva) and explain which tests change; the text uses what the build showed.Partial credit: 0.75 · 0.5 · 00.75: All four activities are covered, but one is thin—for example, reconciliation without a recovery check.0.5: One or two of recognition, resistance, recovery and reinstatement are missing, or the degraded service is not usable by the people who need it. Or the build fails course checks that the written record does not explain. 0: No workable recovery plan, or one that assumes the failed dependency is still available. |
| TESTS RUN · required | Required for submission: a recorded run of your own tests and the course checks on your final code, a second run after you change one test input, and the coverage sentence. Part A cannot be committed without them. Not replaceable: longer writing does not make up for a missing run. A run with failing checks is accepted when your text explains it. The build itself is marked in RECOVER. |
| BOUND · 1 point | 1: States relevant assumptions, the situations covered, and a result you can observe that would make you review the decision. Partial credit: 0.75 · 0.5 · 00.75: A relevant boundary and trigger, but one is imprecise—for example, a trigger that cannot be observed as written.0.5: The boundary is generic (“if problems occur”) or does not match the claim and the plan. 0: No boundary, or a boundary that contradicts the case facts. |
| ACT + EVIDENCE · 1 point | 1: Gives a workable action with clear limits, who is responsible, and evidence someone else can check, while distinguishing checks already completed from checks you plan to do. Partial credit: 0.75 · 0.5 · 00.75: A feasible action and useful evidence, but one element is missing—for example, the responsible role, or whether the evidence is completed or proposed.0.5: The action is vague or not feasible in the case, or the evidence cannot be inspected by someone else. 0: No action, or evidence that is invented or reported as completed when it is only proposed. |
| REFIT · 1 point | 1: Explains how the new evidence affects the initial claim and justifies RETAIN, REVISE or REPLACE with a consistent final answer. Partial credit: 0.75 · 0.5 · 00.75: The effect of the new evidence and the RETAIN / REVISE / REPLACE choice are justified, but the final record leaves one inconsistency with the new boundary.0.5: A choice is stated but not justified from the new evidence, or the final record repeats Part A without addressing the change. 0: No REFIT, or a response that ignores or contradicts the new 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 CLO 6 of the course specification (section B). The Python build, its tests and the coverage step also support CLO 11. It is course-written practice, not an official national readiness assessment or an approved item-weight mapping.
Strong and weak answers for each criterion · how other answers are accepted
| Criterion | Strong example | Weak example |
|---|---|---|
| FIT | Strong: Critical service: an authorized agent retrieves the current task list and records new work. Given facts: the backup restarts; the access service is down. Assumption, marked: the task list on the backup is current. Why: Names the critical service, keeps to the given facts and marks the assumption. | Weak: Resilience means having a backup, and the help desk has one. Why: Confuses a backup with the critical service; no case fact. |
| RECOVER | Strong: Recovery is complete when an agent signs in through the emergency route and completes a real task on data whose integrity was checked. Reinstatement of reporting comes later. Why: Separates recovery from reinstatement and judges it at the user boundary. | Weak: The service recovers when the server restarts. Why: A running process is not a usable service. |
| BOUND | Strong: The plan holds while the emergency identity route is independent of the main access service. If both depend on the same directory, the plan is reopened. Why: Names the dependency and an observable trigger. | Weak: The plan works unless the outage is very bad. Why: No dependency and no observable trigger. |
| ACT + EVIDENCE | Strong: Action: define a degraded mode with paper task cards and a named shift lead. Evidence: a rehearsal record with the access service switched off, proposed. Why: Feasible action, a named role, evidence with its status. | Weak: Train staff and buy a better backup. Why: No specific action, owner or inspectable evidence. |
| REFIT | Strong: The new evidence shows the alternate copy needs the same access service. I replace my recovery step: restore identity through the audited emergency route first. My first plan assumed an independent path. Why: Names what changed, chooses REPLACE with a reason, admits the first assumption. | Weak: I keep my plan; the alternate copy is still there. Why: Ignores that the copy shares the failed dependency. |
Other answers are accepted when: the answer names the critical service, uses only the facts given in the task, separates recovery from reinstatement, and names evidence from a rehearsal or record that someone else can check. A different plan that meets these conditions earns the same marks as the model answer.
The examples are about a different practice case. They show the kind of reasoning that earns the mark, not the answer to this task.
What distinguishes an unsupported answer from a stronger one?
Different practice example · weak: “The backup restarts, so the service recovers.”
Stronger: For a different help desk, recovery requires an authorized operator to retrieve the current task list, record new work, and reconcile it after restoration. A server restart alone does not test that sequence.
The stronger answer names a mechanism, its scope and inspectable evidence. It does not certify a real system. Your assessed answer must address this task’s own facts.
The assignment in nine steps الواجب في تسع خطوات
- 115 minPrepareLecture, the two readings, the five practice questionsاحضر المحاضرة، اقرأ المصدرين، وحلّ الأسئلة الخمسة
- 21 minOpenOpen it with your Student ID, in the same browser every timeافتح الواجب برقمك الجامعي، ومن نفس المتصفح دائماً
- 320 minPart AFIT · artifact · BOUND · ACT + EVIDENCE, 120–180 wordsاكتب حكمك الأول: المشكلة، المهمة، الحدود، القرار والدليل
- 430 minBuildPlan, complete the code, write 3+ tests, Runاكتب الخطة، أكمل الكود، 3 اختبارات على الأقل، ثم Run
- 51 minCommitReview & commit Part A: it becomes read-onlyثبّت الجزء A: يصبح للقراءة فقط
- 62 minNew evidenceIt opens on the page right after you commit. Read itيظهر الدليل الجديد في الصفحة مباشرة بعد التثبيت: اقرأه
- 710 minPart BBoundary status, then RETAIN / REVISE / REPLACE and whyهل تغيّر قرارك؟ اختر وبرّر، ثم اكتب القرار النهائي
- 82 minSignDeclare AI use, type your name, tick the boxصرّح بالذكاء الاصطناعي، اكتب اسمك، وضع العلامة
- 93 minSubmitPrint / PDF, then upload the PDF in Blackboardصدّر PDF وارفعه في Blackboard
Select a step to see it on a picture of this page. Online guide: How to do an assignment.
Before you start
- Save often. Use Save draft while working and download a backup before leaving a shared device.
- Commit, then the new evidence. Part A becomes read-only when you commit, and the new evidence opens on this page straight away. Complete Part B, export the PDF and upload it in Blackboard.
- Ownership check. Your instructor may ask you to explain your Part A and REFIT in a two-minute conversation. Your written work and your explanation should agree. AI may help you practise; the reasoning you submit must be your own.
New to this format? Read the step-by-step guide. The sequence preserves 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.
How this assignment connects to the lecture and the five objectives
ONE METHOD · TWO DIFFERENT CASES
From the classroom card to this assignment
The lecture has 20 slides and three short practice stations: claim + evidence; mechanism + limits; changed condition + revised decision. Here you transfer that reasoning to the separate assessed scenario below. Do not copy the practice answer or submit another full classroom report.
Unchanged: 5 raw points, existing deadline, local draft identity, confirmed Part A commitment, STRESS then REFIT, AI declaration and Blackboard submission. Already completed work does not need repeating merely because the lecture was updated.
Five chapter objectives → existing evidence opportunities
These are local chapter objectives. They do not renumber the approved syllabus outcomes or establish an official national mapping. The lecturer judges correctness and sufficiency; a field being filled is not attainment.
| Chapter objective | Where it is practised / evidenced within this task |
|---|---|
| Objective 14.1 Explain recognition, resistance, recovery and reinstatement. | FIT |
| Objective 14.2 Identify organizational and technical dependencies. | RECOVER |
| Objective 14.3 Interpret the Swiss Cheese model without assuming independence. | transfer question + BOUND |
| Objective 14.4 Perform the stages of survivability analysis. | RECOVER + source application |
| Objective 14.5 Trade off degraded service against confidentiality and integrity. | REFIT + EVIDENCE |
2 · PART A · 20 MINUTES
Assessed scenario · fictional teaching case
A fictional campus transport desk needs to read today's pickup list even when the central scheduling server stops working.
- A copy of the list is updated on the desk device at 06:00. Staff with permission can read this local copy.
- Changes made after 06:00 normally stay on the central server until the next update of the local copy.
- A record shows that a backup server restarted successfully. Nobody has tested the full service from the staff member's point of view.
- During an outage, staff can write changes on an approved paper form.
Your decision: is this backup way of working (fallback) ready for a limited trial? Explain what the desk can safely do and what still needs checking.
Quick word help · معاني المصطلحات
شرح مختصر للكلمات المستخدمة في هذا الواجب. ارجع إليه أثناء الحل.
Words in this case
- Reconciliation
- Comparing records and merging changes when the system returns.
مقارنة السجلات ودمج التغييرات بعد عودة النظام. - Degraded mode
- Keeping essential work going with fewer features.
استمرار العمل الضروري بإمكانات أقل من الوضع المعتاد. - Fresh / stale data
- Data that is recent enough / too old for the intended task.
بيانات حديثة بما يكفي للمهمة / بيانات أقدم من الحد المقبول. - Dependency
- Something else the service needs in order to work.
شيء آخر تحتاجه الخدمة لكي تعمل. - Conflict
- Changes that cannot be safely combined without a decision.
تغييرات لا يمكن دمجها بأمان دون مراجعة أو قرار. - Base version
- The version of the record on which a change was based.
نسخة السجل التي اعتمد عليها الشخص عند كتابة التغيير.
Words used in every assignment
- FIT
- What problem matters, and why?
ما المشكلة المهمة؟ ولماذا؟ - BOUND
- When does your recommendation apply? What would make you review it?
متى يصلح قرارك؟ وما الذي يستدعي مراجعته؟ - ACT + EVIDENCE
- What will you do, who is responsible, and what supports it?
ما الإجراء؟ ومن المسؤول؟ وما الدليل؟ - STRESS
- New information shown after you lock Part A.
معلومات جديدة تظهر بعد تثبيت الجزء A. - REFIT
- Review your decision using the new information.
راجع قرارك في ضوء المعلومات الجديدة. - RETAIN / REVISE / REPLACE
- Keep the decision / adjust it / choose a different decision.
أبقِ القرار / عدّله / استبدله بقرار آخر. - Fact / assumption / proposed
- Given evidence / something you assume / something you suggest doing or testing.
حقيقة معطاة / افتراض يحتاج تحققًا / إجراء أو اختبار تقترحه. - Artifact
- The work you produce: for example a test plan, comparison or set of rules.
المخرج الذي تعدّه، مثل خطة اختبار أو مقارنة أو مجموعة قواعد. - Transfer answer
- Apply a second chapter idea to the question, using your own explanation.
طبّق فكرة ثانية من الفصل على السؤال، واشرحها بأسلوبك. - Mutation test / micro-viva
- Your tests try code with known bugs / a short discussion where you explain and change your code.
اختباراتك تكشف أخطاء مقصودة في الكود / مناقشة قصيرة تشرح فيها كودك وتعدله.
Keep the written response to about 120–180 focused words; use compact tables or notation. Include the source application and transfer answer in that budget. Your Python code, tests and build record are not counted in it. State facts, assumptions and proposed evidence separately. Quote or cite the assigned source precisely; explain its role. Report actual study time at the end.
A1 · FIT · 1 POINT
Name the service that must continue during the outage. Explain how it differs from everything the normal system does. Identify the staff who need it and the people, data or other services it depends on.
PYTHON BUILD · ASSESSED IN RECOVER
Build the merge of paper changes
Write reconcile(central, paper_log). After the central system returns, it must merge the changes recorded on paper into the central list, without losing changes, applying one change twice, or replacing a newer change without checking it. Use the actual results in your RECOVER answer.
First time? Try the not-assessed practice build and a complete worked example on How to do an assignment.
Budget about 30 minutes. Python runs in your browser: nothing to install, and nothing is uploaded. The first run downloads Python once (about 10 MB, internet needed). Passing every check is necessary, not sufficient: your written record must use what the build shows.
Your tests also run against versions of the code with known bugs. Each bug must make at least one of your tests fail. This is called mutation testing. Your build record gives you a small code change to explain in a short discussion (micro-viva), selected using your Student ID. Be ready to make it and explain which tests change and why.
Primary source · about 15 minutes: P. Helland and D. Campbell, “Building on Quicksand,” CIDR, 2009. Read why changes made while disconnected must be merged when the system returns, and why each change needs its own unique ID. Where does your code use that ID? Use the answer in your build plan.
The course checks your build must pass
- a paper change is applied
- the same change is applied only once
- a stale change becomes a conflict, not an overwrite
- a missing pickup is added
- successive changes to one pickup are both applied
- the inputs are not modified
- your own tests: at least three, all passing
- your tests catch every known bug (mutation test)
Keep the given names. Write at least three functions whose names start with test_. Tab inserts four spaces.
Write your plan, then run.
COVERAGE STEP · COURSE OUTCOME 11 · DESIGN AND IMPLEMENT TEST CASES ACROSS TESTING STRATEGIES
The build record measures which lines and branches of your code your own tests run. The course checks are not counted.
- Make your three tests pass and read the coverage lines in the build record.
- Change one input in one of your tests. Run again: the record shows Run 2.
- Write one sentence: which branch is still not tested, and which input would test it.
A2 · RECOVER · 1 POINT
Describe four steps for one outage: recognize the problem (recognition), keep essential work going (resistance), restore the service (recovery), and return to normal working (reinstatement). Include how staff check the age of the local list and merge the paper changes back into the central list. Mark steps that have not been tested as proposed.
A3 · BOUND · 1 POINT
State where, when and by whom the fallback may be used. Explain when an old list or a risk of exposing private information would make it unacceptable. Label any limit you introduce as proposed, not as a measured fact.
A4 · ACT + EVIDENCE · 1 POINT
Choose trial, restricted trial or hold. Name the next action and the person or role responsible. Describe one practice run that checks whether staff can deliver the service, not just whether a server restarts.
Name the test, activity record or review that supports your decision. State the conditions it covers, who checks it, and what evidence is missing. Clearly separate results already available from checks you are only proposing.
ASSIGNED SOURCE APPLICATION · INCLUDED IN THE EXISTING RUBRIC
Give a slide number from the assigned reading. Explain its idea in your own words, then point to the part of your answer it supports or challenges. A slide number alone is not enough.
TRANSFER CHECK · SCORED WITH FIT
Survivability analysis asks how essential work can continue when something fails. Explain why it starts with the essential services and possible failures. Name one dependency on people or working procedures that a server-only recovery test would miss.
Commit is not LMS submission. Confirmation freezes FIT, RECOVER, BOUND, ACT and EVIDENCE before the new information appears.