GRUBkäynnistys

GRUBkäynnistys refers to the boot process managed by the GRand Unified Bootloader (GRUB) on Unix-like operating systems, primarily Linux. When a computer is powered on, the BIOS or UEFI firmware initializes and then loads the bootloader from a designated storage device. GRUB is a common choice for this role.

Upon loading, GRUB's primary task is to present the user with a boot menu. This menu lists the available operating systems and kernel options installed on the system. The user can then select which operating system or kernel to boot, or allow the default option to be loaded after a timeout period.

Once an option is selected, GRUB loads the chosen operating system's kernel and any necessary initial ramdisk (initrd) into memory. It then transfers control to the kernel, which takes over the boot process. GRUB itself does not manage the entire operating system startup, but rather facilitates the initial loading of the kernel.

GRUB is highly configurable. Its configuration file, typically found at /boot/grub/grub.cfg, allows for customization of the boot menu's appearance, timeout duration, default entry, and kernel parameters. This flexibility makes GRUB a powerful and versatile bootloader for diverse system configurations. The term "GRUBkäynnistys" therefore encapsulates the entire sequence of events from the initial firmware handover to GRUB, through its menu selection, and finally to the loading of the operating system kernel.