(Please not that there are several questions about installing Ubuntu from Windows without a CD-Rom. This is not a duplicate of those, because they all recommend a USB stick, which i don't want to do).
Assuming that i have
- an existing 14.04 LTS installation on my machine, with full root access
- enough free disk space, and the knowledge how to create a new empty partition
- no way to access my CDRom and USB ports, or no CDs to burn and no USB stick to spare, or a BIOS that doesn't support booting from anything but the disk, or any other reason why i can't/don't want to create a boot medium
- no fear of the command line, and the ability to boot into a minimal shell and install the rest of the system from there
is there a way to install 16.04 NOT as an upgrade, but in a separate new root partition with dual boot option (if anything goes wrong in 16.04, i want to be able to boot back into the current, known working, installation; the probability of this happening is not part of the question)?
What i'm going to do if i don't get a "useful" answer is:
- make a Virtualbox VM, boot that VM from the iso-file, and install a minimal system to a single root partition within the VM
- create a new partition, run mkfs on it, mount it
- copy that minimal system from the virtual VM hard disk to the mounted partition
- add the mounted partition to my grub menu and reinstall grub
- reboot from the new partition
- use apt-get to install the rest of the system
However, if possible, i'd like to circumvent the VM and "install" the minimal system right from the iso file.