- Building-management system (BMS)
- The supervisory system controlling facility mechanics such as chillers, air handlers, pumps, dampers, fire suppression, and access control. It reads environmental points across the building and modulates cooling and other systems to hold setpoints, sitting above the field controllers that execute the loops.
- Data diode
- A hardware device that physically permits network traffic in one direction only, so telemetry can leave a critical zone while nothing can enter it, enforced by physics rather than configuration. It is the strongest control for exporting monitoring data from sensitive electrical and safety systems.
- Industrial demilitarized zone
- A buffer network between the enterprise and control networks where plant data is published for business consumption so no enterprise device talks directly to a controller. Its defining rule is that no protocol crosses it unbroken; every flow terminates on a broker and a fresh session begins on the far side.
- Operational technology (OT)
- The layer of controllers, sensors, and actuators that governs the physical world of a facility, deciding how power flows, how cooling runs, and when equipment starts or stops. In a data center it is the plant that keeps the compute alive, and its priorities and constraints differ fundamentally from information technology.
- Programmable logic controller (PLC)
- A ruggedized industrial computer that executes a fixed control program on a deterministic scan cycle, reading inputs and writing outputs every few milliseconds. It runs no general-purpose operating system, and its real-time determinism is both its strength and the constraint that forbids aggressive security tooling.
- Safety-instrumented system
- An independent last-resort controller whose sole function is to bring a physical process to a safe state when conditions become dangerous. Because it is the backstop against catastrophe, an attacker who neutralizes it first has removed the protection before manipulating the process, so it warrants the strongest available isolation.
- Supervisory control and data acquisition (SCADA)
- An architectural pattern, not a single product, combining distributed field controllers doing real-time work, a communications layer, and a central system that visualizes state, logs history, and lets operators issue commands. It is the seam where human intent meets machine action across a large facility.
- Zones and conduits
- A segmentation model that groups assets sharing a trust level and function into a zone, and permits communication between zones only through a conduit, the single controlled path where policy is enforced and traffic inspected. Small zones and few conduits shrink the blast radius of any single compromise.