[ubuntu-in] OT - Multiple Booting of GNU/LInux OS's

[ramnarayan.k at gmail.com]

Hi

For the past few days have been wanting to try other distros's along
with my existing Ubuntu 7.04. So i installed Mandriva 2008 spring on an
external USB HD (my laptop supports booting of USB).

For the second OS (being installed on the external usb HD) i made an
additional /boot and pointed the grub loader to be installed on this
section.

However when i try and boot of the USB HD the boot loader does not appear.

So a few questions :
1. Why does not the second OS work
2. Is there a way i can add the boot loader for the Second OS (Mandriva
2008) to my existing Ubuntu OS menu.lst.

There was a possibility to ask the Mandriva to install the boot loader
to the onboard HD section but it seems that Mandriva cannot / does not
see all the existing OS's that are there.

Currently my main Ubuntu 7.04 boot options are
Ubuntu
MS windows
MS Windows (recovery)

Mandriva sees only
Ubuntu 7.04
and
MS Windows

The windows recovery partition does not appear.

****
I tried copying a section of the USB HD's mandriva menu.lst to the 
ubuntu menu.lst, specifically the following lines

title linux *(Mandriva)*
kernel (hd0,4)/vmlinuz BOOT_IMAGE=linux 
root=UUID=9be80552-9983-4062-b4da-1247596cbbae  resume=/dev/sda5 
splash=silent vga=788
initrd (hd0,4)/initrd.img

i could not figure out the hd* section so randomly changed it to hd1 and 
the device /dev/sda5 to /dev/sdb5.

But while it showed up on the Ubuntu boot loader it just said that 
target device could not be found, when i tried booting to Mandriva.

So will it work if the correct hd device is pointed to ?? and any idea 
how i find the correct hd device since both Ubuntu and Mandriva identify 
them separately.

thanks
ram
PS I could post the menu.lst in case its required.