Corrections log
Every accepted correction, public and dated — caught by readers or by the guide's own editorial and adversarial review passes. Spotted an error? Use “Suggest an edit” at the end of any chapter; accepted fixes are credited.
warm-water DLC (45–60 °C+) often does not [need a heat-pump lift]
Corrected the heat-reuse thermodynamics: a 45–60 °C return cannot supply a 60–70 °C (3G) network without a heat pump — it feeds low-temperature (4G/5G) networks directly and 3G networks with a smaller lift.
PUE category-1 (annualized, fully sub-metered)
Corrected reversed ISO/IEC 30134-2 PUE categories: Category 3 is the advanced IT-equipment-input measurement; Category 1 is the basic UPS-output figure.
NIST SP 800-88 Rev.1
Updated media-sanitization references to NIST SP 800-88 Revision 2 (final September 2025, superseding Rev. 1).
most high-risk-system obligations apply from 2 August 2026
Updated the EU AI Act timeline for the 2026 omnibus: stand-alone (Annex III) high-risk systems comply from 2 December 2027 and product-embedded systems from 2 August 2028 (Council approval 29 June 2026). Also removed an unreproducible ISO 42001 RFP-share statistic.
GB200 ~80 L/min flow, ~2.4 MW cooling capacity
Replaced the mixed GB200 cooling record with two named OEM profiles: OCP MGX Rack Rev. 1.1 (120 kW, ~85% liquid capture, up to 130 L/min) and HPE GB200 NVL72 (132 kW nominal, 115/17 kW split, 192 kW busway, 1.3 MW in-row CDU for up to 8 racks). Per-rack flow ranges are now labeled as guide derivations.
Tier III at 99.982%, Tier IV at 99.995%
Removed Tier-to-availability-percentage mappings across chapters, quiz, comparison, calculator, and decks — Uptime disavowed those figures; Tier certifies topology properties (concurrent maintainability, fault tolerance). Historical note retained in Chapters 0.4 and 12.1.
inducing a fault on the path that should still be carrying load
Removed the unsafe 2N IST instruction to improvise a second fault on the live surviving path; the test matrix now comes from the facility FMEA with defined preconditions, instrumentation, and abort criteria.
the BESS sinks the pulse peaks and sources the troughs
Reversed BESS power-flow direction corrected: to flatten grid draw the battery discharges into load peaks and recharges in troughs. The unsafe 'commissioned against a real induced grid fault' language was replaced with controlled methods (relay secondary injection, hardware-in-the-loop, planned breaker-opening tests against protected load banks).
2(N+1) — sometimes written 2N+1
Corrected redundancy notation: 2(N+1) and 2N+1 are different topologies (at N=3: eight units vs seven). Also distinguished active/active from active/standby 2N operation.
a rack busbar rated to roughly 1,400A
Corrected NVL72 busbar current: 132 kW at 48 V is ~2,750 A — ~1,400 A is the per-bar rating of the paired busbars (~2,800 A aggregate), consistent with Chapter 7.13.
~266 ML/yr water make-up
Corrected Appendix B's water arithmetic: WUE is defined per kWh of IT energy, so 50.7 MW IT × 0.5 L/kWh × 8,760 h = ~222 ML/yr (the table had applied WUE to facility energy).
~$9,000/min for cascading incidents
Fixed a unit error: $300,000/hour is $5,000/minute. The inconsistent $9,000/min figure was removed.
a hardware fault every few minutes around the clock
Corrected the 100k-GPU fault-cadence extrapolation: 7 days per 512 GPUs scales linearly to roughly one fault every ~52 minutes, not every few minutes.
together nearly 59% of all failures were GPU/HBM-related
Corrected the Llama 3 failure arithmetic: faulty GPUs (30.1%) plus HBM3 (17.2%) are 47.3% — the ~58.7% figure is Meta's full GPU-related grouping, now stated separately.
Busway / busduct lead-time floor eased: ~30–52 wk → ~27–52 wk (VAWN electrical lead-time index, June 2026: standard runs average ~27 wk; custom engineered runs at the top). Same 2026-07-12 fact-check.
H100/H200 GPU lead time re-stated: 6–12 mo → ~3–12 mo, bimodal — spot H100s improving to weeks while H200 and full enterprise systems sit at the top. Same 2026-07-12 fact-check.
800G optical transceiver lead-time floor raised: ~20–50 wk → ~36–50 wk. The 20-week floor predated NVIDIA's March 2026 $4B EML pre-buy, which pushed non-priority allocations out. Same 2026-07-12 fact-check.
HV switchgear & circuit-breaker lead time corrected: ~45–80 wk → ~100–155 wk. The old headline figure described MV-class gear; true HV breakers run ~100–155 wk (Duke Nicholas Institute / Wood Mackenzie). Prose aligned in Ch 2.1 and 2.3. Caught by the 2026-07-12 adversarial fact-check of the Lead-Time Tracker.
Dispatches Atom feed: entry ids were improperly escaped and the feed lacked an RFC-4287 author element; both fixed. Dual adversarial review.
Glossary: “$”-prefixed terms (e.g. $/GPU-hr) matched with wrong word boundaries, creating spurious in-text term links. Dual adversarial review.
Lead-Time Tracker: the register query missed several lead-time figures (regex under-match) and could list the same figure family twice; matching and number-family dedupe fixed. Dual adversarial review.
Project-finance calculator: the IRR solver could return a misleading result for negative-input edge cases; inputs are now clamped and the failure mode returns “—” instead of a wrong number. Dual adversarial review.
Rear-door heat-exchanger ceiling corrected to ~50–100 kW per rack in chapters that had drifted to lower values — Chapter 5.3 holds the canonical derivation. Caught in the dual adversarial model review (Claude Fable + GPT-5.5 high).
Every figure traced to one vendor blog was removed or re-sourced after the source failed credibility review — the register now carries the replacement citations. Editor-in-chief review pass.
Behind-the-meter gas fleet sizing corrected to the ~1 GW-class canon for the flagship deployments discussed; prior text overstated it. Editor-in-chief review pass.
NVL72-class rack weight standardized to the ~3,000 lb canon; earlier chapters carried divergent figures. Editor-in-chief review pass.
Warm-water direct-to-chip loop temperatures standardized to the 45 °C supply / 65 °C return canon; several chapters carried inconsistent pairs. Editor-in-chief review pass (446 fixes across the guide).