“The installer works by creating a disk image of a pre-installed
ubuntu system on the hard disk (downloaded with a bittorrent
downloader integrated into the installer, or a standard http
download when we find mirrors), and then installing GRUB for
windows, which can be chain loaded by the existing boot loader, and
which then loads the linux kerner and initrd from the ntfs
partition. The initrd is modified to support mounting the image
file mentioned above as a root file system, and then continuing the
boot process like a normal installation.”