An operating system (OS) is system software that manages computer hardware and software resources and provides common services for application programs. The OS acts as an intermediary between the hardware and the software running on it — handling tasks like scheduling processes, managing memory, controlling input and output, and providing a file system. Without an OS, each application would need to manage hardware directly.
Common operating systems include Linux, macOS, and Windows for general-purpose computers, and specialized variants for embedded devices, mobile phones, and servers. Linux is the dominant OS for server and IoT workloads.
In This Home
All RPi lab servers run Linux (Raspberry Pi OS or a derivative). The Mac workstation used for management runs macOS. The ESPHome microcontroller devices do not run a full OS — they run bare firmware directly on the hardware.