Figure A3 — MTBF Qualification Tiers
Hardware-tracked Mean Time Between Failures determines whether abstractions may propagate beyond their provisioning c-list. Three tiers gate downloadability: Isolated (local only), User-regulated (individual distribution), and Namespace-regulated (full namespace access). The hardware enforces these gates — software cannot override MTBF qualification.
MTBF QUALIFICATION PROGRESSION
TIER 1: ISOLATED
Local only
MTBF < threshold_user
Scope:
• Runs only in provisioning c-list
• Cannot be distributed
• Cannot be downloaded
Use case:
New or untested abstractions
Development / debugging
🔒 LOCKED to local namespace
MTBF improves
TIER 2: USER-REGULATED
Individual distribution
threshold_user ≤ MTBF < threshold_ns
Scope:
• Can be shared with individuals
• Downloaded by named users
• Still scoped to user level
Use case:
Proven abstractions shared
between trusted parties
🔓 User-level distribution
MTBF improves
TIER 3: NS-REGULATED
Full namespace access
MTBF ≥ threshold_ns
Scope:
• Full namespace distribution
• Downloadable by any CTMM
• Proven reliability record
Use case:
Production-grade abstractions
System libraries, services
🔓 Full namespace access
HARDWARE ENFORCEMENT
✔ MTBF counters are maintained by hardware, not software — unforgeable
✔ Tier transitions are automatic when MTBF crosses threshold
✔ FAULT resets MTBF counter — a single failure can demote an abstraction
✗ Software cannot override MTBF qualification. No backdoor. No admin bypass.
MTBF COUNTER FORMAT
Fault counter: increments on every FAULT attributed to this abstraction
Invocation counter: increments on every successful CALL to this abstraction
MTBF = invocation_count / fault_count (higher = more reliable)
Both counters are hardware registers. Reset only on abstraction destruction. No software read/write path.