warm shell
A finished, powered and cooled data centre building, ready for servers to be plugged in.
A warm shell is a data centre building that is complete in every respect except the computers: walls up, power connected, cooling running, network in place. All it needs is racks. The term became widely quoted after Microsoft chief executive Satya Nadella used it to explain why his company had AI chips sitting in inventory that it could not switch on.
It captures a shift in what limits AI. For years the bottleneck was buying enough chips. Increasingly the bottleneck is electricity, substations, cooling and planning permission, none of which move faster because you spend more money. A modern AI buildout is a construction and utilities project first, and a semiconductor project second.