docs(adr): amend 0002 — blank identity key caps confidence at Limited, blank-key change semantics; SLOT-A filled (PR-15/16, ID-4); glossary term degraded identity

2026-08-31 22:30:40 +05:30
parent bf83ac5481
commit 580fab26be
3 changed files with 14 additions and 5 deletions
@@ -44,6 +44,10 @@ _Avoid_: Daily summary, daily stats
 A span of observation history within which the drive's controller identity is unchanged and counters are monotonic; write deltas are never computed across a segment boundary.
 _Avoid_: Counter reset handling, drive swap detection

+**Degraded identity**:
+The condition where a controller segment's identity key is blank because no identifier rung produced a value; replacement detection then relies on write-counter continuity alone, and projection confidence is capped.
+_Avoid_: Identity error, unknown device, virtual drive
+
 **Endurance baseline**:
 The write-endurance value a projection consumes, chosen by precedence: a verified override when one exists, otherwise an unverified override, otherwise a coarse implied baseline derived from vendor wear — each labeled as such.
 _Avoid_: TBW value, failure threshold, max writes