Captured the native HistorianAccess.GetHistorianInfo(out HistorianInfo, out err)
and decoded the wire: over 2020 WCF, GETHI is a named-value query whose only
working key is "HistorianVersion" (response ~30 bytes = the version string).
Probed 7 storage-mode key names -> all ok=False/err. The 518-byte HISTORIAN_INFO
struct + EventStorageMode@514 is the 2023R2 HCAL-native/gRPC model (confirmed
from the decompiled 2023R2 source); on 2020 the native client derives the mode
outside the WCF wire.
Version is already exposed (ProbeAsync/GetRuntimeParameterAsync), so no hollow
GetHistorianInfoAsync is shipped (same disposition as R1.3 timezone). This
completes the reachable 2020-WCF M1 read surface; remaining M1 = config writes
(gated on explicit request) or gRPC/2023R2-only items.
RE aids kept: harness `historian-info` scenario, Capture-HistorianInfo.ps1,
decode-historian-info-capture.py, and StringHandleProbeDiagnosticTests
.GETHI_CandidateInfoNames (asserts the named-value-only finding; gated).
Docs: wcf-historian-info.md (new) + roadmap/matrix/wall-doc updates. 230 tests green.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC
Joseph Doherty