Linux for developing Ada real-time applications
Linux and RT systems

Linux for soft real-time systems
Real-time priorities
Processes run to completion
Preemptive scheduling between processes
Regular priorities
Time sharing
A low priority process will eventually be run

Linux for hard real-time systems
Access to the hardware
Memory allocation can be controlled
Access to the resources cannot be prioritized
Reactivity
Latency can be up to several milliseconds
Kernel cannot be preempted