Joe composed on 2017-11-16 19:27 (UTC):
I see the date of the page is 2015,
IIRC, that 2015 update was all about updating and/or replacing broken links.
Multiple OSes will still use one overall bootloader, which may or may
not redirect to other bootloaders. It is common, therefore, to use a
single physical partition for /boot, common to all *nix OSes....
Mounting the same single primary partition as /boot to all *nix OSes invites
virtually the same trouble that installing Grub to MBR causes. Absent user
intervention, each OS thinks it owns the space, so at updates times, each stomps
on whatever is there at the time, eventually exhausting its freespace with a
multitude of diverse kernels and initrds. Only one OS, or no OS, should mount
the bootable physical partition to /boot. Others can either have their own
bootloader installed to their own / filesystem, or be used without their own
On most of my PCs, the bootable primary is never mounted to /boot. I manage it
manually myself, providing direct loading of kernels and initrds, as well as
chainloading entries, and configfile entries, the latter two used primarily when
prior kernels are to be booted, the former for most booting.
For someone doing multiboot the first time, it's easiest, if not a requirement,
for the first installation to have the primary mounted to /boot. The subsequent
installations either need to have no bootloader or bootloader only installed to
/; or, the newer can be configured to mount the primary on /boot, and the
original, prior to its next boot, preferably immediately prior to starting the
new installation, reconfigured to not mount the primary on /boot, not manage the
bootloader installed there, and relocate its content to its own / filesystem.