ARINC 653
An avionics software standard defining temporal and spatial partitioning together with operating-system service interfaces for integrated modular avionics.
ARINC 653 is built around a strict idea: avionics applications sharing a processor should not be able to consume one another's time budget or memory space without controlled boundaries. Partitions provide that isolation through scheduled temporal windows and spatial separation.
The standard also defines the services through which application software interacts with the operating environment. Scheduling processes inside a partition is not the same layer as scheduling partitions across the module; keeping those layers separate matters when reasoning about worst-case behaviour.
ARINC 653 Temporal and Spatial Partitioning develops the partition schedule, health-monitoring and critical-system isolation aspects in more detail.