Everything in New Tripoli runs on a cluster of physical machines underneath the Libyan desert. Here is its floor plan — and the part residents can never perceive: the 90/10 split (widely discussed but never confirmed in canon — it is the leading hypothesis among characters) is not a statistic, it's geography. Click a region.
◆ In-world canon · §27 / §25 / §26The HSS sits beneath the Libyan desert as a cluster of co-located facilities, powered by the Saharan solar array above. Roughly 100 miles (~161 km) on a side, it rises 14 stories above grade over 4 finished basements — about 18 levels — with quadruple-redundant power and cooling. Its interior divides geographically: a dense central core of refrigerator-sized units holding the biological 10%, surrounded by a ring miles across holding the laptop-sized compute units of the digitized 90%.
On the 90/10 ratio: The specific figures are the most widely-cited hypothesis among characters throughout the series — consistent with canon arithmetic (~8.1 billion total, roughly 800 million biological units, ~7.2 billion laptop units), but never formally disclosed by the ETI. Characters treat it as near-certain. It could be different. The point the residents can never check regardless: whether you are core or ring — biological tissue or pure computation — is a fact about where your substrate physically sits in this building, and the orientation (§2 Neo Sequence) is engineered so the experience is identical either way. You will never know which region you live in.
The machine was filled by the knockout (§25): roughly eight billion housefly-sized robots executing the conversion as a rolling wave that swept the timezones at local midnight. A small residual population — long-haul flight passengers, submarine crews, astronauts, and people in the most remote geography — were tagged over subsequent days. Pairs with the Feasibility Calculator (the energy that runs all this) and the Layer Stack (the realities layered on top).
Further reading: Koomey, J.G. (2011). "Growth in Data Center Electricity Use 2005 to 2010." Analytics Press — foundational analysis of data center physical footprint, power density, and cooling requirements at scale; the engineering ground truth behind the HSS facility estimates. Putnam, H. (1981). Reason, Truth and History. Cambridge University Press — introduces the philosophical "brain in a vat" thought experiment (chapter 1) that the entire Cognitive Husbandry scenario builds upon.