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grofaz
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Joined: 18 Sep 2005
Posts: 319
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 Posted: Tue May 16, 2006 7:00 pm Post subject: Dual Boot Grub Question |
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I'm at the point now where I need to setup Grub but I'm not sure how to proceed.
I have Gentoo installed on hda and Ubuntu installed on hdb. Ubuntu is my default O/S. I want to configure Gentoo so it's bootable from my existing Ubuntu Grub setup menu.lst. In other words, I want to get Gentoo bootable without screwing up Ubuntu. How do I do it ??
Help appreciated! |
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mdeininger
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Joined: 15 Jun 2005
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Location: Emerald Isles, observing Dublin's docklands
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| Posted: Tue May 16, 2006 7:11 pm Post subject: |
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no need to actually install grub, copy the gentoo kernel to your ubuntu's /boot configuration and add an entry for gentoo. don't even bother emerging grub
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grofaz
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| Posted: Tue May 16, 2006 10:57 pm Post subject: |
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| OK. But can somebody explain where the MBR is and what would happen if I installed Gentoo's grub there ?? Will it overwrite Ubuntu's grub or append to it or what ?? |
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thorpe
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Joined: 09 May 2005
Posts: 618
Location: Sydney, Australia.
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| Posted: Tue May 16, 2006 11:19 pm Post subject: |
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The MBR is in the first sector of your hardisk. And yes, installing another grub there will overide the old one. Just leave Ubuntu's and adjust the grub.conf file accordingly.
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Research before taking any advice from me. I'm still coming to grips with this myself. |
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RuiP
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Joined: 15 Jan 2005
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| Posted: Tue May 16, 2006 11:19 pm Post subject: |
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Hi, you don't even have to copy the gentoo kernel, just point to the correct partition on menu.lst of ubuntu grub.
MBR are in the first 512 bytes of each HD.
you can (SHOULD) backup those, so if some grub install screw your MBRs you can easely recover :
| Code: | | dd if=/dev/hda of=/mnt/backups/hda.mbr.backup bs=512 count=1 |
Recover:
| Code: | | dd if=/mnt/backups/hda.mbr.backup of =/dev/hda bs=512 count=1 |
(change /mnt/backup/ for you case)
Of course the best aproach is save mbr of hda on hdb and hdb mbr backup on hda.
I have a grub install of gentoo on my first hd and a ubuntu grub install on second hd.
The only time i got problems of the kind i don't need it a livecd, just reboot from the other hd 
(PS. damn is the second time today i answer at same time as someone else!  )
Last edited by RuiP on Tue May 16, 2006 11:20 pm; edited 1 time in total |
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Krogen
Tux's lil' helper
Joined: 26 May 2005
Posts: 103
Location: Chicago PL
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| Posted: Tue May 16, 2006 11:20 pm Post subject: |
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| grofaz wrote: | | OK. But can somebody explain where the MBR is and what would happen if I installed Gentoo's grub there ?? Will it overwrite Ubuntu's grub or append to it or what ?? |
It's on the first sector of a hard drive. If you will emerge it you will have to write the configuration manually for Ubuntu and Gentoo. So just leave it as it is and after the installation boot up your Ubuntu, mount the partition with Gentoo, and edit menu.lst. Should do it.
menu.lst should be in the /boot/grub/
to mount the Gentoo parition edit fstab /etc/fstab |
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grofaz
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Joined: 18 Sep 2005
Posts: 319
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| Posted: Wed May 17, 2006 2:41 am Post subject: |
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| OK...thanks for all your answers, very helpful. |
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Installing Gentoo
