Does a separate boot partition ensure that grub doesn't get deleted easily?
 

Hi,
To expand on my question asked above, i would like to know if having a separate /boot during installation of a linux distro ensures that the grub does not get lost when i format the / partition. Because if i install grub in /, formatting / implies the grub is lost and so no other OS like windows xp will boot as the bootloader is totally lost.
If having a separate /boot is useful, what should be the necessary space and filesystem for the same?

Thanks.

Yes.
Size depends on how many kernels you have - but make it 100 Meg and you should be fine. I use ext2 (habit), but no real reason not to use ext3.