On 08/09/2014 05:23 AM, Alan McRae wrote: > No problems Joe. I have done this multiple times. > > I assume you have Fedora 20 on sda (the first disk) with > the bootloader (grub2) on sda. Your BIOS will be set to boot sda. > > You install CentOS 7 on sdb (obvious). > > Your options are with the bootloader (grub2). If you install > the bootloader on sdb the two systems will remain separate. > You will have to change the BIOS to boot either sda (F20) or sdb (C7). > > The way I prefer would be to install the new bootloader on sda > (overwriting the current configuration). > Your BIOS will still boot sda which will take you into > the grub2 menus which will show both Fedora 20 and CentOS 7. > > You need to be aware that in the above configuration sda will > boot into /boot on sdb (C7) which will have the dual boot menus. > Don't wreck this directory or you won't be able to boot F20 (easily). > > The F20 and C7 installers are very good. They scan the disks for > linux and Windows installations and add them into the boot menu for you. > > I have a laptop which boots C7, C6, F20, XP and 3 versions of Android > using grub2. > > Alan > Alan, Thank you for your reply. I was concerned that if, during the C7 install, I put the bootloader on sda that it would wipe out what was already there and prevent me from booting F20. Apparently this is not the case. However, I decided to put the bootloader on sdb so I could easily wipe out the C7 install and use the drive for something else. I did the install from the C7 DVD disk. Maybe I missed something but once I indicated I only wanted to use the sdb disk (checkmark on icon), I did not have the option as to where to put the bootloader. After the install, when I boot the computer I go directly to F20. If I press the ESC key when booting I get a BIOS bootloader menu. Miraculously, sdb is on the list. Apparently the BIOS is smart enough to recognize that sdb is bootable and, therefore, puts it on the list. Thanks, Joe