Define each independent starting snapshot
In this invented model a completed snapshot is a valid independent starting state, and whole contiguous log segments can extend it. Candidate A starts 10:00, has logs to 10:10 and 10:20, then a missing 10:20–10:30 segment. Candidate B starts at completed 10:25 and has a whole 10:25–10:28 segment. Requested cutoff 10:28; choose the freshest complete endpoint not later than it. Snapshots are internally complete by supplied evidence.
| Candidate | Starting snapshot /chain | Latest supported endpoint |
|---|---|---|
| A | 10:00; complete to 10:20, gap next | 10:20 |
| B | 10:25; complete 10:25–10:28 | 10:28 |
| Requested | Cutoff 10:28 | Do not exceed cutoff |
Extend each candidate through its own chain
- Validate each starting snapshot separately
- Find each contiguous supported endpoint
- Choose the freshest eligible endpoint
A later log cannot jump A’s gap, but an independently complete B snapshot does not require A’s earlier chain.
Which candidate reaches the cutoff and how much later is it than A’s endpoint?
Show the worked answer
B reaches 10:28, eight minutes later than A’s 10:20. A alone is short eight minutes, but its missing segment does not invalidate the independently complete B starting point.
Choose a point within the requested cutoff
| Case | Decision | Reason |
|---|---|---|
| UseA only | Latest 10:20 | Gap stops that chain |
| UseB snapshot plus its log | Reaches 10:28 | Independent complete start |
Record B’s snapshot and log identities as the selected material set, then rehearse the resulting output. Selecting sufficient materials does not prove execution succeeded.