[wellylug] Grub issues

[Jethro Carr]

okay,

this is the worst grub config file I have ever seen! The Mepis installer
must have gotten REALLY confused.



I'm tired so here's how grub works, according to LFS:

"Grub uses its own naming structure for drives and partitions, in the
form of (hdn,m), where n is the hard drive number, and m the partition
number, both starting from zero. This means, for instance, that
partition hda1 is (hd0,0) to Grub, and hdb2 is (hd1,1). In contrast to
Linux, Grub doesn't consider CD-ROM drives to be hard drives, so if you
have a CD on hdb, for example, and a second hard drive on hdc, that
second hard drive would still be (hd1)."

Once you get the hang of it, it's quite logical.



this should help you understand the changes I've made to your
configuration.



> - Selecting second entry above (new windows installation, hda2) fails to
> boot

title Windows at hda2
> rootnoverify (hd0,-2)
> chainloader +1

this should be:

title Windows at hda2
rootnoverify (hd0,1)
chainloader +1

I have no idea why there is a negative there.



> - Selecting third entry above (old windows installation, hdb1) fails to boot

title Windows at hdb1
> rootnoverify (hd1,-3) find no explanation of
> chainloader +1

should be:

title Windows at hdb1
rootnoverify (hd1,0)
chainloader +1


no idea how it got that.



> - Selecting entry four above, hdb5, which has no operating system,
> actually boots the windows installation on hda2

title Windows at hdb5
> rootnoverify (hd1,2)
> chainloader +1

should be:

title Windows at hdb5
rootnoverify (hd1,4)
chainloader +1


again, no idea.



> I have looked at the Grub documentation, but can't find anything that
> might suggest what is going on. (Also can find no explanation of the
> minus signs in the partition naming, which would be interesting.) In
> fact we could work around it by simply renaming the entries above, but
> it's a dirty fix, and doesn't contribute at all to my understanding or his.
> 
> Also it would be nice to allow booting of the older windows if possible,
> although I'm not sure whether that's possible with it on the second drive??

I belive it should work - grub tricks windows into thinking it's on the
first drive.




here's the final config file. give it a try:

===========================

timeout 15
color cyan/blue white/blue
foreground ffffff
background 0639a1
gfxmenu /boot/grub/message

title MEPIS at hda6, kernel 2.6.10
kernel (hd0,5)/boot/vmlinuz-2.6.10 root=/dev/hda6 nomce quiet
splash=verbose vga=791
initrd (hd0,5)/boot/initrd.splash

title Windows at hda2
rootnoverify (hd0,1)
chainloader +1

title Windows at hdb1
rootnoverify (hd1,0)
chainloader +1

title Windows at hdb5
rootnoverify (hd1,4)
chainloader +1

title MEMTEST
kernel /boot/memtest86.bin

==========================



-- 
-- Jethro Carr

jethro.carr at jedolinux.com

http://jethrocarr.jedolinux.com
http://jethrocarr.jedolinux.com/index.php?page=cv/cv.php

http://www.jedolinux.com
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