🟡 PRESERVATION_OPERATOR

RTT/1 Operator Specification — archive_org Module#

Identity#

  • Operator Name: PRESERVATION_OPERATOR
  • Operator Family: B‑Ops (Boundary / Substrate Operators)
  • Module: archive_org
  • Purpose: Evaluate the object’s substrate stability, drift risk, and multi‑layer structure to determine which versions are most reliable for continuity‑aligned retrieval.

Purpose (One Sentence)#

The PRESERVATION_OPERATOR assesses the object’s substrate format, stability score, drift risk, and multi‑layer flags to determine which snapshots are structurally trustworthy.

Inputs#

Input Type Description
target URL The object being evaluated.
collection_id string Collection context from COLLECTION_OPERATOR.
regime_profile string Combined regime identity from COLLECTION_OPERATOR.
continuity_kernel list Stable structural elements from LINEAGE_OPERATOR.
transformations list Structural changes from LINEAGE_OPERATOR.

Outputs#

Output Description
format The detected substrate format (html, pdf, image, ocr, mixed).
stability_score Numerical stability estimate (0–1).
drift_risk Expected drift level based on substrate + regime.
multi_layer_flags Indicators for mixed or layered substrates.

Operator Guarantees#

  • No content‑based inference.
  • Substrate classification is structural, not semantic.
  • Stability score is evidence‑based, not assumed.
  • Drift risk is predictive, not retrospective.
  • Mixed substrates are handled explicitly, not collapsed.

Substrate Stability (RTT/1)#

Substrate Stability Notes
pdf high Static, layout‑preserving.
image high Stable but incomplete.
html medium Layout‑dependent, drift‑prone.
cms‑html medium/low Template‑driven, redesign‑prone.
ocr low Lossy, structurally degraded.
mixed variable Requires multi‑layer analysis.

Drift Risk Levels#

Level Meaning
low Stable substrate, minimal expected drift.
medium Occasional structural changes.
high Frequent redesigns, migrations, or lossy layers.

Multi‑Layer Flags#

Examples:

  • pdf + html
  • image + ocr
  • html + js‑rendered
  • flash + html5

Multi‑layer objects require careful stability evaluation.

Operator Procedure#

  1. Detect substrate format(s) for the target.
  2. Evaluate stability based on:
    • substrate type
    • collection context
    • regime profile
    • continuity kernel
    • transformations
  3. Compute stability score (0–1).
  4. Assign drift risk (low/medium/high).
  5. Identify multi‑layer structures.
  6. Emit outputs for DRIFTBOUND_RETRIEVAL_OPERATOR.

Failure Modes#

  • Ambiguous substrate: mark as mixed.
  • Missing layers: lower stability score.
  • OCR‑only snapshots: mark as high drift risk.

Hand‑Off to Next Operator#

Outputs feed directly into:

DRIFTBOUND_RETRIEVAL_OPERATOR#

  • format
  • stability_score
  • drift_risk
  • multi_layer_flags

Example (Synthetic)#

Input:
  target = "https://example.gov/records"
  collection_id = "govdocs"
  regime_profile = "institutional (CMS-era)"
  continuity_kernel = ["header", "footer", "records-index"]
  transformations = ["CMS migration", "PDF layer added"]

Output:
  format = "html + pdf"
  stability_score = 0.78
  drift_risk = "medium"
  multi_layer_flags = ["html", "pdf"]

RTT/1 Mindset#

  • Substrate determines trustworthiness, not content.
  • Stability is measured, not assumed.
  • Mixed substrates require layer‑aware reasoning.
  • Drift risk must be explicit in the final summary.

Updated