# Rack-Scale Computing **Domain:** Computer Architecture / Data Center Infrastructure **Doc Type:** Canonical Technical Concept **Maturity:** Developed ## Definition **Rack-scale computing** is an architecture in which compute, accelerator, memory, network, storage, power, cooling, management and serviceability are designed as a coupled system at rack scale. The shift is from rack-as-furniture to rack-as-computational-organ. ## Historical Lineage Conventional rack servers enclosed most power conversion, cooling and device relations within individual chassis. Scale computing centralized selected functions and standardized sleds. Accelerator systems intensify the trend because electrical density, memory locality, scale-up communication and liquid distribution can no longer be optimized independently. ## Governing Variable Rack-scale architecture governs locality and coupling: which resources can communicate efficiently, share infrastructure, fail together and be serviced as a unit. ## Material and Computational Manifestation Power shelves, busbars, accelerator trays, high-bandwidth memory, scale-up switching, cooling manifolds, coolant distribution units and rack telemetry form the physical architecture. [[wiki/UALink|UALink]] changes the accelerator domain; [[wiki/CXL|CXL]] changes memory and device composition; [[wiki/Open Rack V3|Open Rack V3]] standardizes facility-facing interfaces. ## Relation to Governance The rack becomes a managed domain whose local state is exposed to higher schedulers and control planes. Topology-aware scheduling is therefore partly a material decision: workload placement must respect communication, heat, power and failure boundaries. ## Constitutional Question and Failure Modes Shared resources improve utilization but enlarge correlated failure and administrative authority. An operator who controls rack firmware, fabric management or power caps can alter the effective capacity of every subordinate component. ## Related Ontology [[wiki/Rack|Rack]] · [[wiki/Open Rack V3|Open Rack V3]] · [[wiki/AI Factory|AI Factory]] · [[wiki/Optical Fabric|Optical Fabric]] · [[wiki/Control Plane|Control Plane]]