Identify the source, received copy and analytical derivative

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Day 17 — Identify the source, received copy and analytical derivative

Theory and mechanism. “Original” is ambiguous unless the record identifies the layer. The producer's retained record set, the custodian's exported object, the first case copy and an analyst's transformed file are distinct objects even when their visible rows agree. Name the layer and preserve a source pointer. An analyst cannot prove that the first received file is the producer's original merely by calling it original.csv. An export may already be a selected or transformed representation of a changing source.

At 09:18, C09 supplies a case-copy receipt and two readable rows with a reported 09:16 approval. It does not supply the source object/version, exact query or actual byte count/digest. At 09:22, C10 supplies a separate screenshot observation. The received case materials are useful, but the lesson's readable transcription is not the underlying CSV or image byte sequence. Keep missing byte-level fields as not supplied, not zero, failed or guessed.

Custody mechanism. For every real handling event, an evidence trail should identify item/version, source pointer, acting role, action, time basis, approved scope, destination or receiving role, check performed and result. Distinguish “sent,” “received” and “checked”: a sender report does not establish recipient receipt, and receipt does not establish a successful comparison. Later clarification is a dated supplement with its actual author/time and a pointer to the prior entry. Backdating today's digest would conceal a gap in the earlier record. This improves traceability but does not certify lawful handling or admissibility.

Worked contrast. A receipt reading “09:18: C09 and C10 verified” is wrong twice: C10 arrives later, and neither card supplies a completed byte check. Separate entries retain C09's 09:16 approval/09:18 receipt and C10's 09:22 receipt with its conditional display time. A proposed derivative ledger can then say: “Future normalized timeline → C09/C10 case references → transformation to retain raw and normalized times → analyst and version to be recorded when performed.” That is a plan, not a new received file.

If a hypothetical analyst later redacts a copy for restricted discussion, the derivative needs its own identity, transformation description and disclosure gate. Retain the preserved case copy under its actual policy; do not overwrite it with the redacted version. A changed digest after redaction can be expected and must be explained. Matching digests for two alleged copies address byte identity only under the comparison's trust assumptions; they do not authenticate a misleading filename or missing producer path.

Laboratory and decision. Predict and run the retained C4X receipt-state illustration. Its CTN_C09_LIMIT output models missing integrity fields; it is not a hash computation. Its sha256:toy value and Boolean checked flag are declarations, not measurements. The contradiction control with approved=False and an alleged received copy exposes a limitation of that toy's first-failure label: retain and flag the inconsistency rather than using REQUEST_ONLY to erase a reported handling event. No such inconsistent new receipt is added to canonical C09.

Practice and limit. Complete EX017 as two receipts plus a three-layer source/copy/derivative ledger and one proposed transfer record. Use the worked answer to check statuses. A complete-looking form can still describe an unperformed transfer; only actual evidence permits advancing its state. C09's receipt does not establish a source hold or stop the producer's reported deletion.

Continue studying — course Day 17: Previous: Day 16 · Week 4 index · Course index · Next: Day 18.

Exercise for this lesson

EX017 — Two receipts. Objective: distinguish object identity, handling events and interpretation. Input: C09/C10 as available at 09:22, the C4X illustration and Day 17. Create separate receipt lines with source and object layer, event/display time, receipt time, approval where supplied, missing byte/provenance fields and one limit each. Add a source/case-copy/proposed-derivative ledger and a proposed transfer entry whose unperformed fields remain pending. Explain why a later digest needs a dated supplement and why C4X flags do not prove custody. Rubric: 0 = merged chronology, fabricated transfer/check or V4 digest assigned to C09; 1 = honest receipts with incomplete layer/handling distinction; 2 = two traceable receipts, separate layers, append-only supplement and explicit proposed transfer status. Worked answer.

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EX017

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Worked answers

EX017 — Model receipts. C09: IdP detailed CSV described as 08:50–09:05 source range, two reported events 08:58/08:59, approval at 09:16, case copy received 09:18; object ID, byte count and digest not supplied; completeness and integrity unverified. C10: support screenshot displays 11:21 UTC+02:00, conditionally 09:21 UTC; ticket receipt 09:22; original file identity, capture device, clock and cache context unknown; displayed symptom only. V4's digest must not be copied into the C09 receipt. If a later collection fills a field, add a dated supplement, not a silent edit of the original receipt.

Additional worked reasoning (EX017 — Two different receipt statuses.): C09 has a reported permission at 09:16 and case-copy receipt at 09:18 for events 08:58/08:59, but no supplied source object ID, byte count or digest; its integrity/completeness remain unverified. C10's display is 11:21 UTC+02:00, conditionally 09:21 UTC, with support receipt at 09:22, missing original capture clock/cache context. Do not make a single “09:18 verified evidence” entry for both. A receipt is evidence of receiving the claimed object, not proof of authoritative meaning.

Week 4 Day 17 — worked layer and handling record. C09's received-case-copy layer has reported approval 09:16, receipt 09:18 and described events 08:58/08:59; producer object/version, byte count, digest and exact method remain not supplied. C10 is a separate screenshot item received 09:22, with raw display 11:21 +02:00 and conditional 09:21 UTC; file identity, capture clock/cache and authoritative state remain unknown. For each, distinguish the described producer, received case material and proposed analytical derivative; none of the missing underlying bytes is supplied by the book's text. A proposed transfer row may identify case item and permitted receiving role while marking operator, transfer time, recipient acceptance and check pending. Later metadata belongs in a dated supplement, never a backdated original receipt. C4X's six lines classify declared states only; checked=True with sha256:toy is not a measured digest. A contradictory received/unapproved variant must be retained and flagged, not erased by the toy's REQUEST_ONLY label. An access log improves traceability but does not certify admissibility or a source hold.