What processes are started and initialized when the computer is turned on?

When turning on the computer, a sequence of processes occurs that loads the operating system:

1. Power-On Self Test (POST) — basic hardware check (memory, processor, devices).
2. Bootloader loading — BIOS or UEFI searches for a boot sector on the storage device and loads the OS loader.
3. Bootloader initialization — the loader (e.g., GRUB) loads the operating system kernel into memory.
4. Kernel startup — the kernel initializes drivers, mounts the root filesystem.
5. System services and daemons startup — the init system (systemd, SysVinit) starts, launching necessary services and user processes.

These stages ensure the transition from power-on to a ready-to-use operating system.