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Re: debian installation issue



Greg Wooledge composed on 2021-06-11 15:07 (UTC-0400):

> On Fri, Jun 11, 2021 at 09:38:37PM +0300, Semih Ozlem wrote:

>> How to check where grub is installed? And what is a friendly guide to
>> learning about grub?

> GRUB should be installed on the *disk* (not on a partition) that you
> intend to boot.										
Not to detract from the wisdom of the rest of Greg's excellent reply, but TBC,
this statement is religion at one extreme, opinion at the other, not fact. Note he
wisely did not say "must", but "should". For most traditional (BIOS/MBR; designed
for "Windows" PCs) configurations, it's probably prudent to put the bootloader on
the "disk". For pure Debian installations, as opposed to multiboot, whether or not
to install it on the "disk" really doesn't matter.

OTOH, putting a bootloader on the MBR of a disk on a PC designed for Windows is a
relative newcomer to the world of booting such a PC. I've been installing
operating systems on IBM-compatible PCs for more than 3 decades. Not once have I
intentionally installed Grub on an MBR. In the dearth of instances where it did
happen I wiped whatever caused it, and started over with
DOS/OS2/Windows/Linux-compatible MBR code on the MBR. IOW, Grub can live elsewhere
than on the MBR.

A less innocuous error is not clearly qualifying the quoted statement to apply
only to non-UEFI boot environments, which usually means an MBR-partitioned boot
disk. On a UEFI installation, which requires GPT partitioning, the first sector
normally contains nothing until near its end, where a disk identifier and the
start of the disk's multi-sector partition table begin. No executable code is
required on this sector.

With a UEFI "BIOS", the boot process begins rather differently than on an MBR-only
system. On a UEFI system's ESP (Extensible Firmware Interface System Partition; a
quasi-"boot" partition), there are no files containing the string "grub" in their
name. Thus it seems to be a debatable issue whether "bootloader" is actually an
appropriate name for Grub 2, as its primary purpose seems to be presenting a menu
from which to select what kernel, initrd (if any), and kernel command line
parameters (if any) to load into RAM to /continue/ the boot process initiated by
the UEFI firmware.
-- 
Evolution as taught in public schools is, like religion,
	based on faith, not based on science.

 Team OS/2 ** Reg. Linux User #211409 ** a11y rocks!

Felix Miata


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