Originally Posted by XiaoKJ
With regards to chainloading, let me clarify...
grub works in 2 stages --- the first stage mainly just reside somewhere and points to stage 2. stage 1 can be installed in your partitions (primary/logical it doesn't care) or MBR. stage 2 resides in the partition with the grub config files.
normally, if you only have 1 partition for all, stage 1 and 2 can all be in the root partition. if you have /boot as a separate one, stage 1 and 2 will be in front of the partition.
alternatively, and more commonly, stage 2 can just be at /boot/grub/stage2, and stage 1 will point to stage 1.5, which enables grub to read your filesystem and look for stage 2.
so, in your case, you should be installing stage 1, stage 1.5 and stage 2 to /boot, and all other distros will install their own grub/lilo to their own root partitions. why? without a corresponding stage 1, stage 2 may not boot. so you may not be able to use stage 1 of your primary distro to boot stage 2 of another distro. as long as your primary grub installation is working, you can always use that to chainload your whatever new distro, and the new grub installation will take over.
that way, you don't have to edit your primary distro's grub installation everytime you install a new distro.
in other words, if you decide to include your new distro's grub clauses into your primary installation, then once you install a new distro you have to update menu.lst again --- a tedious job!
Finally, my reason for not installing to MBR is that it has no point --- if MBR is empty, it will normally just load your primary partition which has your primary grub installation. MBR is very important and I'm sure you wouldn't want to endanger it.