Re: Grub overview/tutorial available

[Simon Kitching]

On Sat, 2010-04-17 at 17:39 +0200, Vladimir 'φ-coder/phcoder' Serbinenko
wrote:
> Simon Kitching wrote:
> > Hi All,
> >
> > Just FYI, I've written up what I've learned about Grub during the last
> > few weeks and put it up here:
> >
> > http://people.apache.org/~skitching/MineOfInformation/linux/Booting_Linux_on_x86_with_Grub2.html
> >
> > This is more detailed than simple "user level", but doesn't get into any
> > code details. More at the "advanced sysadmin" level perhaps.
> >
> > Any feedback/corrections welcome; I'm fairly new to Grub so probably
> > have some mistakes in there.
> >   
> "This tool(grub-emu) can be used to install Grub." <--- wrong (outdated)

Fixed.

> " Note also that there are a few commands that can be run in the “grub
> shell” that are not available in a real Grub environment (because they
> would be pointless)," <--- likewise

Fixed.

I wrote this because in the command list documentation
(http://grub.enbug.org/CommandList), there is reference to a "loopback"
command as a replacement for grub legacy 'device' command, and I can't
see what use that would have in a real grub boot enviroment.

But as I'm not really sure about this, I'll just delete this section.

> insmod /boot/grub/normal.mod normal <-- only one of 2 arguments and it
> won't set prefix resulting in further problems. Correct action is:
> 
> set prefix=(<disk>)/boot/grub
> insmod normal
> normal
> 
> 'Grub “legacy” (the 0.x series) could only boot kernels that support the
> “multiboot” specification.' <--- grub legacy has a linux loader too
> 'As Grub2 boots kernels by invoking a helper module (“linux”, “xnu”,
> “bsd”), it can boot any kernel for which the appropriate helper module
> has been written. Of course if a kernel supports multiboot, then writing
> such a helper module is much simpler!'
> Modules are NOT ''helpers'. They are separate loaders. and multiboot
> needs no 'helpers'

Fixed.

> 
>     linux $root/mykernel root=xyz ---->  linux ($root)/mykernel root=xyz
> 
> ' search –set=MYDEV – search.label mylabel MYDEV' at very least actually
> try the commands you supply

Fixed.

Grub-emu doesn't work for me, and I eventually got tired of rebooting my
(only) PC to test things. Should have tried harder though :-(.

Thanks for your comments. Thanks also to Seth...

Regards,
Simon