[Grml] Boot loaders

Michael Schierl schierlm at gmx.de
Tue Oct 6 23:00:07 CEST 2009

Jason White wrote:

>> 1. Am I right about grub being able to accept commands at the boot 
>> screen allowing booting of anything (even if it isn't in the menu list)?
> yes. Also, grub doesn't need to overwrite the boot sector whenever you upgrade
> a kernel; all it needs to do is change a configuration file to refer to the
> new kernel image and init-rd image.

Grub also allows editing the configured commands and supports tab
completion of filenames, so that you don't have to type the whole
command line. Although I doubt this can be done when you cannot see the
text and the cursor on the screen. If you press 'c' from the menu you
can just enter your own (new) commands. Enter "boot" when you have
finished and the commands will be executed.

Note that Grub (like LILO) can only boot from drives accessible by your
BIOS as disk drives; if you load it from a fixed drive it will neither
be able to load a kernel from a CD or an USB drive, nor will it boot
from CD or USB directly. Booting from floppy (or a second internal disk)
works, though.

> 2. Is it possible to get the grub boot screen to beep like the lilo one 
> as described in the accessibility information on the GRML wiki?

In Grub legacy you can embed a Ctrl+G character into one of the menu
titles, which are shown at bootup automatically (if you put it before
the 50th or so character; long titles are truncated in the menu display).

In Grub2 there is a "play" command in the configfile which claims to be
able to play beep sequences (of different length and pitch) defined in a
file on the PC speaker. I never tried that though, and I could not find
any documentation about the file format.

>> 3. Have you got any extra reasons you would suggest changing to grub 
>> from lilo or is there a different boot manager you would suggest?
> I would suggest going straight to Grub 2 and skipping grub-legacy if you can.
> Debian Sid has already moved to Grub 2, Ubuntu are heading in that direction
> and I expect other distributions to follow. Grub 1 hasn't been maintained for
> years, but only recently has Grub 2 matured to the point of being widely
> usable.

The main difference is that Grub1 is "rock stable" by now, and Grub2
sometimes has its glitches. But maybe the glitches are all worked out by
now, I last looked at Grub2 1.96 which was release in February 2008.

Hope this helps,


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