ORIGINAL COMPANY-CONTEXT PRACTICE
Recover a machine-service command after a lost acknowledgment
Original practice scenario: A hypothetical semiconductor-equipment service sends a diagnostic command to a machine. The acknowledgment is lost, and repeating the command might alter state. Define the recovery protocol.
Written for independent practice using company context; this is not a verified question from a company interview.
A REASONED APPROACH
Model answer.
Classify the command by its effects before deciding whether it can be retried. A missing acknowledgment creates uncertainty about execution, which should be resolved through durable command status where possible.
Work through it
- Give the command an identity, payload fingerprint and authorized target generation; the machine records acceptance and completion evidence under that identity.
- Distinguish read-only diagnostics from state-changing operations, defining duplicate handling and preconditions for each command class.
- After communication recovery, query status before resubmission, reconcile device and service records, and escalate an unknown effect instead of assuming failure.
Tradeoffs to discuss
- Durable local receipts add storage and protocol complexity but reduce ambiguous retries; pure status polling may delay service recovery.
Common pitfalls
- A device restart can invalidate an old target generation or erase volatile evidence.
- This practice protocol must retain separate operational safety interlocks and must not authorize remote actions by itself.