Problems dual booting FC4 and Slack 10.2
 

Hey guys I am having a problem with dual booting. I am quite new at this, but this is what I have tried to do thus far. Here is a picture of my hard drive:

hdc1 = 19 GB linux
hdc2 = 1 GB linux swap #both for FC4
hdc3 = 19 GB linux
hdc4 = 1 GB linux swap #both for Slack

The bootable partition is hdc1, which is where i installed grub for FC4. I installed Slack just fine, but I did not install the boot loader. Then, in FC4, I mounted /dev/hdc3 and copied the contents of /boot into the the /boot file on hdc1, so I could boot both operating systems. I then changed my grub.conf file to look like this: (this is what I do not understand)

When I try to boot Slack, it says it is unable to mount the root partition.

Under the slackware title, I don't understand how grub is configured, i.e. what numbers to put in where, specifically for the "root(hd0,0)" and "kerenl ........." lines. Could anyone tell me how the file is configured or what values I should put in there to be able to choose which system to boot?

Grub numbers harddrives and partitions differently than linux. In linux, the first partition of the first harddrive is /dev/hda1, while in grub it is (hd0,0). If root (hd0,0), then kernel /example would be /mountpointofhda1/example.

There is an error in the 3rd line for Slackware

kernel /boot/isolinux/vmlinuz root=/dev/hd3

change hd3 to hdc3

Also I assume you have setup

Slackware's isolinux/diag1.img correctly in hdc1.

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You could have saved a lot of bother to chainload Slackware with it hdc3 partition.

Steps are

(1) Boot FC4, log in as root, drop to terminal mode, make a temporary directory /mnt/hdc3, mount device hdc3 on it

mkdir /mnt/hdc3
mount /dev/hdc3 /mnt/hdc3

(2) Replicate Slackware boot loader Lilo in root partition hdc3, then exit back to FC4

lilo -b /dev/hdc3
exit

(3) Amend /boot/grub/menu.lst to change

title Slackware
root(hd0,0)
kernel /boot/isolinux/vmlinuz root=/dev/hd3
initrd /boot/isolinux/diag1.img

to

title Slackware @ hdc3 by chainloading
root(hd0,2)
chainloader +1

By chainloading you use Grub to boot Slackwar's Lilo. The 3 lines of Grub commands are universal with which you can boot any DOS, Windows, XP, Linux, BSD and Solaris. The only change you need in the partition number.

Grub counts from 0 and so (hd0,2) = hdc3

I am assuming your hda and hdb are either a CD drive or unattached casuing Linux to register its first hdd as hdc. There is nothing wrong with it.

Thank you so much for your very helpful posts. I have everything working in order :)