Starsi BIOS (LEGACY) muze mit pouze jeden bootloader nainstalovany do MBR
To dual boot Arch Linux with another Linux system, you need to install another Linux without a bootloader, install os-prober and update the bootloader of Arch Linux to be able to boot the new OS.
Note: I use GRUB as a bootloader because it is the most popular Linux bootloader. If you use any other bootloader, you can get the overview of the process here, but you would need to research yourself the command to update your bootloader.
Dualboot - TOTO FUNGUJE
1. nainstaluju PRVNI distibuci (Mint)
2. restartuju
3. nabootuju z live GParted/ Partion Magic a upravim HDD tak aby tam prvni partisna s PRVNI distibuci byla zmensena na pulku, do druhe pulky pridam partisnu pro DRUHY OS a ponecham SWAP kde je pote restart
4. dam CD/FLASH a nainstaluju do druhe partisny DRUHY OS tj. (Manjaro/Antix atd) - POZOR nezadavam ze chci instalovet GRUB
5. restart
6. nabootuju do Mint (GRUB zatim neukazuje vyber linuxu to je OK), zadam sudo update-grub a tim updatuju grub ktery pozna ze tam je uz druhej os a dam restart
7. po restartu by se melo v GRUBu obevit nove menu s vyberem, do jakeho OS chci nabootovat :)
OS-PROBER
Tento navod pouziva OS-PROBER je nutno ozdkouset!!!! pozor testovano na ARCH linux a Mint Linux
1. nainstalovat PRVNI OS linux (Arch)
2. nainstalovat DRUHY OS linux (Mint) (bez bootloader tj asi bez GRUB)
3. nabootuju do PRVNIHO OS a namontuju partisnu s DRUHYM OS (zjistim lsblk kde je druhy os - napr. sda1 PRVNI a sda2 DRUHY OS <===> sudo mount /dev/sda2 /mnt/sec
4. nainstaluju os-prober
5. spustim os-prober <===> sudo os-prober
5. updatuju grub <===> sudo update-grub
Typical layout for 2x distro;
/dev/sda1 = /boot = shared
/dev/sda2 = / = distro 1
/dev/sda3 = / = distro 2
/dev/sda4 = /home = shared
/dev/sda5 = swap = shared
What I've found with recent installations of Testing is that, if I allow it to install grub2 to the MBR, it detects any other operating systems correctly but fails to add them to the grub menu. However, running update-grub after installation corrects this, so I've concluded that this is still the easiest approach.
Legacy boot
Install the first linux distro , you need to create the root partition and a swap partition , install your system the Grub should be installed on the Master Boot Record assuming on sda.
You can create a separate /boot partition , home ,etc... for the 1st linux distro.
To Install the second linux distro , you can create only the root partition
It is possible to use the same swap partition.
You can create a separate /boot , home ... for the second linux distro
You can mount and use the same home , swap , /boot partition during the second linux install , but it is not recommended to use the same boot partition
Some linux distro will ask you for the path to re-install GRUB on the MBR ,you can reinstall it also you can skip it.
To skip the re-installation of GRUB by choosing the root partition of the second linux distro as path e,g: sda4 (not sda), After rebooting your system run grub-mkconfig -o /boot/grub/grub.cfg from the first linux distro to get a new entry.
UEFI
it is necessary to get an ESP partition to install the first linux distro , a root and a swap partiton and more .
When you install the second linux distro do not format the ESP just mount it to install the boot-loader.then Create the root partition.
How to share files between the 2 OS?
You don't have a problem of sharing between linux OS.
