1. Software that manages multiple application environments each sharing a single host OS kernel, with no full OS per workload
2. Software that creates isolated virtual environments each with its own complete guest OS, sitting directly on physical hardware
3. A system that monitors pressure gauges and controls valve positions across 12 pipeline pumping stations from a central operations center
4. A device with purpose-built hardware and firmware that controls a traffic intersection's signal timing — no general-purpose OS, cannot load additional software