On 2024-04-27, Michael <confabul...@kintzios.com> wrote: > On Saturday, 27 April 2024 17:53:25 BST Dale wrote: >> Howdy, >> >> I'm installing Gentoo on another old box. To be consistent I like >> to use cgdisk, GPT I think it is called, to partition all my >> drives, regardless of size. > > GPT is the partition table structure, which is more advanced than > the old DOS partition table structure. > >> Thing is, Grub works differently with GPT than it does with the old >> DOS or whatever it is called, like fdisk does in the old days. > > GRUB works the same, but the disk/partition table structure is different.
No, grub doesn't work the with GPT disk labels as it did with DOS disk labels. With DOS disk lables, Grub uses empty space between the boot sector and the first partition as a location to store it's core image file. That empty space does not exist when using GPT disk label. When using a GPT disk label, Grub requires that you need to create a "BIOS Boot" or "Grub Boot" partition so that Grub has somwhere to store it's core image[1]. https://wiki.gentoo.org/wiki/GRUB#BIOS_with_GPT https://wiki.archlinux.org/title/GRUB#BIOS_systems [1] There is an alternative installation method where Grub will record the disk block numbers occupied by the core image files as they reside in the normal filesystem. That's extra work to maintain and might not be reliable for some filesystem types, so it's not recommended.
