Metal
The boxes themselves — cores, memory, disks
In a nutshell
Strip away the houses and the rooms and you’re left with the silicon: processors, memory, and the disks beneath them. This layer is only the owned hardware — the cloud machines that rent their capacity by the month aren’t metal, because nothing there is yours to hold. What remains is the cluster’s matched server processors, two standalone desktop-class chips, the error-correcting memory that keeps long-running workloads honest, and the mirrored NVMe everything is written to. The exact models and capacities are recorded in the Hardware Manifest; this layer is about what each component is and why it’s there.