Ubuntu stopped support for non-PAE systems with release 12.04.
But it isn’t that complicated to get an actual ubuntu run on a non-PAE system: Just compile the kernel yourself. So you have to install build-essential linux-source and kernel-package, then extract the kernel source inside /usr/src.
I did create a packer file that does everything needed to setup the a virtual machine patches kernel config and compile the kernel inside it, see https://github.com/pfichtner/non-pae-kernel-compiler
After that cd into the linux-source directory and call make menuconfig.
Navigate to “Processor type and features” -> “High memory support” and switch it off, now “PAE” should be deseleted.
Exit menuconfig and run “make-kpkg -j 4 –initrd –append-to-version=-non-pae kernel-image”. This will take some time. After that you can install the resulting kernel deb package (which can be found in /usr/src” by calling “dpkg -i ” on the non-pae system.
Of course there is the problem on how to run the installer on an non-pae system. Two possible solutions:
- Start the installation with an old ubuntu version, install the non-pae kernel and update the system to the actual ubuntu version
- take a look at debootstrap (install the whole non-pae system in a directory of another linux system and copy it after that to the target machine)