9.2.2. Características do GRUB

O GRUB oferece um verdadeiro ambiente de linha de comando pré-SO em máquinas x86. Esta característica dá ao usuário flexibilidade máxima para carregar sistemas operacionais com opções específicas, e para colher informações sobre o sistema. Há anos, várias arquiteturas não-x86 têm empregado ambientes pré-SO que permitem a inicialização a partir da linha de comando.

GRUB supports Logical Block Addressing (LBA) mode. LBA places the addressing conversion used to find files in the hard drive's firmware, and is used on many IDE and all SCSI hard devices. Before LBA, boot loaders could encounter the 1024-cylinder BIOS limitation, where the BIOS could not find a file after the 1024 cylinder head of the disk. LBA support allows GRUB to boot operating systems from partitions beyond the 1024-cylinder limit, so long as the system BIOS supports LBA mode. Most modern BIOS revisions support LBA mode.

GRUB can read ext2 partitions. This functionality allows GRUB to access its configuration file, /boot/grub/grub.conf, every time the system boots, eliminating the need for the user to write a new version of the first stage boot loader to the MBR when configuration changes are made. The only time a user needs to reinstall GRUB on the MBR is if the physical location of the /boot/ partition is moved on the disk. For details on installing GRUB to the MBR, refer to Seção 9.3, “Instalando o GRUB”.