Dual boot issues

By MrDarcy
Aug 9, 2005
  1. Hi all,

    I have a query regarding dual (or multi) booting a PC.

    I have a slave drive set up with three primary partitions of 200MB each (to use as three different /boot partitions for three different versions of linux) and then an extended partition to house four logical partitions as the swap and three different / file systems.

    The intention was to place the bootloader into the MBR of the slave and then to be able to choose which version of linux to boot by using the BIOS to select the slave drive. It would appear the bootloader contained in the MBR of the slave drive does run, since I get the "LI" output (and nothing else). My interpretation of this is that lilo can't find the /boot partition to carry on the second stage of the boot process. Can this set up work?

    I know this is not the easiest way of doing it, but I'm more interested in understanding the boot process of a PC than simply getting it to run. (the journey is more important than the destination!!!).
  2. jobeard

    jobeard TS Ambassador Posts: 11,170   +989

    the primary boot manager needs to be on the primary disk.
    items in the boot mgr may then refer elsewhere,
    eg logical parition(s) on the primary drive or anything else on the secondary

    With windows already installed on the primary, LILO will preserve it
    and add the others as secondary items for selection at boot time
  3. MrDarcy

    MrDarcy TS Rookie Topic Starter

    problem resolved

    I'm replying to my own question, I always say the best way to learn is by one's own endeavours, so here goes:-

    You can boot from the slave disk, but the bootloader is not very aware of its environment. This means it doesn't know its on the MBR of the second disk, as far as its concerned it is hd0 (in grub format) even though it is in fact hd1.

    The conf files therefore reference "kernel (hd0,0)/boot/vmlinuz root=/dev/hdb1" and that is not a typo (this is a 7GB root (and boot) fs on the first primary partition on the slave disk).

    Now all I need to do to boot from it is hit esc during boot up to activate the BIOS boot menu and select the slave drive. This means other family members of the PC don't get any "weirdness" from their trusty PC.
  4. jobeard

    jobeard TS Ambassador Posts: 11,170   +989

    kind of slick:) most users would not prefer to filp in-out of BIOS but rather
    have the choices managed by the boot loader. That said, it is easy to see
    WHY you took this approach.
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