[gentoo-user] Grub2 and use-flags

[gentoo-user] Grub2 and use-flags

[Kevin O'Gorman]

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I'm running grub 2 it seems.  I don't know when that started, or what
difference it makes compared to legacy grub.  I guess I don't need to know.
But a recent post had me looking at use-flags, and I was a bit surprised to
find (ncurses -static).  If this refers to the part of grub that I run when
setting up or tweaking while Linux is already running, I guess that's
sensible.  But does it have any effect on the boot sequence (because both of
those would strike me as badly broken).

I also wonder what -custom-cflags would be used for, and I don't get any
sensible answer from flagedit(1).

Just an inquiring mind...

[I] sys-boot/grub
     Available versions:  0.92-r1 0.94-r1 0.96-r1 0.96-r2 ~0.96-r3 ~0.97
0.97-r2 0.97-r3 0.97-r4 0.97-r5 0.97-r6 ~0.97-r8 0.97-r9 **1.98 **9999
{custom-cflags debug multislot ncurses netboot static truetype}
     Installed versions:  0.97-r9(06:16:18 AM 03/03/2010)(ncurses
-custom-cflags -netboot -static)
     Homepage:            http://www.gnu.org/software/grub/
     Description:         GNU GRUB 2 boot loader

-- 
Kevin O'Gorman, PhD

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Re: [gentoo-user] Grub2 and use-flags

[Bill Longman]

On 06/18/2010 08:17 AM, Kevin O'Gorman wrote:
> I'm running grub 2 it seems.  I don't know when that started, or what
> difference it makes compared to legacy grub.  I guess I don't need to
> know.  But a recent post had me looking at use-flags, and I was a bit
> surprised to find (ncurses -static).  If this refers to the part of grub
> that I run when setting up or tweaking while Linux is already running, I
> guess that's sensible.  But does it have any effect on the boot sequence
> (because both of those would strike me as badly broken).
> 
> I also wonder what -custom-cflags would be used for, and I don't get any
> sensible answer from flagedit(1).
> 
> Just an inquiring mind... 
> 
> [I] sys-boot/grub
>      Available versions:  0.92-r1 0.94-r1 0.96-r1 0.96-r2 ~0.96-r3 ~0.97
> 0.97-r2 0.97-r3 0.97-r4 0.97-r5 0.97-r6 ~0.97-r8 0.97-r9 **1.98 **9999
> {custom-cflags debug multislot ncurses netboot static truetype}
>      Installed versions:  0.97-r9(06:16:18 AM 03/03/2010)(ncurses
> -custom-cflags -netboot -static)
>      Homepage:            http://www.gnu.org/software/grub/
>      Description:         GNU GRUB 2 boot loader

I think it's used in both places, Kevin. You certainly see ncurses when
you're in grub and doing a setup for instance, but you'd need ncurses at
boottime in order to highlight which grub record you wanted to edit and
all the fancy stuff it does out there before the OS begins.

My hunch about -custom-cflags is that, by default, grub would want to
make its binary as generic as possible. But if you want to see your grub
menus that many nanoseconds sooner, you could always apply your own über
mega hyper powered extra special smokin' grub.

And finally, don't even mention how braindead the "new" improved grub
is. I wonder how anyone can feel that having to write six paragraphs in
some one-off bash-like language, which needs to be debugged, is better
than four lines in a config file.

Bill

Re: [gentoo-user] Grub2 and use-flags

[Peter Humphrey]

On Friday 18 June 2010 16:17:12 Kevin O'Gorman wrote:
> I'm running grub 2 it seems.  I don't know when that started, or what
> difference it makes compared to legacy grub.  I guess I don't need to
> know. But a recent post had me looking at use-flags, and I was a bit
> surprised to find (ncurses -static).  If this refers to the part of
> grub that I run when setting up or tweaking while Linux is already
> running, I guess that's sensible.  But does it have any effect on
> the boot sequence (because both of those would strike me as badly
> broken).
> 
> I also wonder what -custom-cflags would be used for, and I don't get
> any sensible answer from flagedit(1).
> 
> Just an inquiring mind...
> 
> [I] sys-boot/grub
>      Available versions:  0.92-r1 0.94-r1 0.96-r1 0.96-r2 ~0.96-r3
> ~0.97 0.97-r2 0.97-r3 0.97-r4 0.97-r5 0.97-r6 ~0.97-r8 0.97-r9
> **1.98 **9999 {custom-cflags debug multislot ncurses netboot static
> truetype} Installed versions:  0.97-r9(06:16:18 AM
> 03/03/2010)(ncurses -custom-cflags -netboot -static)
>      Homepage:            http://www.gnu.org/software/grub/
>      Description:         GNU GRUB 2 boot loader

I see the same version availability on my box, but I'm running grub-
static 0.97-r9. The reason is that, months and years ago, the dynamic 
version did not interpret TAB but just moved the cursor. I don't know 
whether that's been fixed.

The fact that grub-static says it's the legacy boot loader, and that 
it's at the same version as you quote, makes me wonder whether the 
dynamically linked version really is grub 2 - it seems to be lacking 
several files that are in the grub 2 in (I think) Ubuntu.

-- 
Rgds
Peter.

[gentoo-user] Legacy GRUB vs GRUB2

[Tanstaafl]

On 2010-06-18 12:17 PM, Bill Longman wrote:
> And finally, don't even mention how braindead the "new" improved
> grub is. I wonder how anyone can feel that having to write six
> paragraphs > in some one-off bash-like language, which needs to be
> debugged, is better than four lines in a config file.

This brings up a question I've been meaning to ask...

Since I have no desire to experience this new 'improved' GRUB, but don't
like LILO - how long will it be before I'll be forced to make a choice?
Meaning, how long will legacy GRUB still be supported?

Re: [gentoo-user] Legacy GRUB vs GRUB2

[Dale]

Tanstaafl wrote:
> On 2010-06-18 12:17 PM, Bill Longman wrote:
>    
>> And finally, don't even mention how braindead the "new" improved
>> grub is. I wonder how anyone can feel that having to write six
>> paragraphs>  in some one-off bash-like language, which needs to be
>> debugged, is better than four lines in a config file.
>>      
> This brings up a question I've been meaning to ask...
>
> Since I have no desire to experience this new 'improved' GRUB, but don't
> like LILO - how long will it be before I'll be forced to make a choice?
> Meaning, how long will legacy GRUB still be supported?
>
>    

If I read the home page correctly, they are not really doing much more 
than bug fixes on the old grub.  That was my reading at least.  I'm 
dreading that day too.  I sort of like my old grub.  I started on lilo 
and grub has seriously grown on me.  I'll switch to the new grub tho.  I 
have NO plans to go back to lilo.  None whatsoever ! !

Dale

:-)  :-)

Re: [gentoo-user] Legacy GRUB vs GRUB2

[Stroller]

On 18 Jun 2010, at 17:17, Bill Longman wrote:
> ...
> And finally, don't even mention how braindead the "new" improved grub
> is. I wonder how anyone can feel that having to write six paragraphs  
> in
> some one-off bash-like language, which needs to be debugged, is better
> than four lines in a config file.


Can someone possibly explain exactly what's wrong with GRUB2?

I've just taken a look at the wiki guide link posted by Max Bräutigam,  
and it all looks exactly the same as current GRUB and no more  
complicated, apart from optional sections to change the resolution and  
font at the top of the config file.

Stroller.

Re: [gentoo-user] Legacy GRUB vs GRUB2

[Maximilian Bräutigam]

Am 23.06.2010 08:53, schrieb Stroller:
> 
> On 18 Jun 2010, at 17:17, Bill Longman wrote:
>> ...
>> And finally, don't even mention how braindead the "new" improved grub
>> is. I wonder how anyone can feel that having to write six paragraphs in
>> some one-off bash-like language, which needs to be debugged, is better
>> than four lines in a config file.
> 
> 
> Can someone possibly explain exactly what's wrong with GRUB2?
> 
> I've just taken a look at the wiki guide link posted by Max Bräutigam,
> and it all looks exactly the same as current GRUB and no more
> complicated, apart from optional sections to change the resolution and
> font at the top of the config file.
> 
> Stroller.
> 

Hi Stroller,

there is nothing complicated, the only thing you should take care of is,
that you run grub-mkconfig to get an initial grub.cfg and grub-install
and you should in case of system failure know, how to boot with a
livecd, chroot your environment and switch back to your old grub/config.
Help with chroot you'll find here:

http://www.gentoo.org/doc/en/handbook/handbook-x86.xml?full=1#book_part1_chap6

So, be brave!
der Max

Re: [gentoo-user] Legacy GRUB vs GRUB2

[etienne.lorrain]

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> Can someone possibly explain exactly what's wrong with GRUB2?

The main problem of GRUB2/GRUB4DOS is that it is entering the Linux
kernel by the partially documented 32 bits entry point:
http://www.mirrorservice.org/sites/alpha.gnu.org/gnu/grub/grub-1.98.tar.gz/grub-
1.98/loader/i386/linux.c?extract=true

That means you are no more executing the real mode part of the linux
kernel, you are using some real mode memory structures set-up by GRUB2.
Those structures have been more or less identical to those of Linux at
some point in the past.

That means that some kernel options which were working with GRUB1 (like
EDID and EBIOS disk identifications) are no more working, and no more
evolutions can be done in the real mode part of the Linux kernel (like
increasing some structures, moving their base address...).
Those evolutions would only be working with kernel booted with GRUB1,
LILO or Gujin, but not with GRUB2.
Disclaimer: I am not unrelated with the GPL bootloader Gujin at sourceforge.

When entering the Linux kernel by the 32 bits entry point on ia32/amd64
has been discussed on lkml, it was seriously criticised.

For instance, because the boot disk can no more be determined safely
(the BIOS on most machine can tell the PCI address of a drive, but
it is unsafe to call the BIOS after so many modifications in protected
mode done by GRUB2), you get distributions switching to all UUID mode 
- which is a major pain when one of your hard disk fails and you copy
it byte per byte onto a spare disk, leading to UUID conflicts.

Also, some amd64 PC seems to want a BIOS call when they will run a
64 bits kernel (linux kernel real-mode code), I am not sure that one
is done by GRUB2.

And a third problem is that you need the 32 bits libraries to compile
GRUB2, even on a clean 64 bits machine.

Just my $0.02,
Etienne.




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