The installer may be booted using boot files placed on an existing hard drive partition, either launched from another operating system or by invoking a boot loader directly from the BIOS.
A full, “pure network” installation can be achieved using this technique. This avoids all hassles of removable media, like finding and burning CD images or struggling with too numerous and unreliable floppy disks.
The installer cannot boot from files on an NTFS file system.
This section explains how to add to or even replace an existing linux installation using either LILO or GRUB.
At boot time, both bootloaders support loading in memory not only the kernel, but also a disk image. This RAM disk can be used as the root file-system by the kernel.
Copy the following files from the Debian archives to a
convenient location on your hard drive, for instance to
vmlinuz (kernel binary)
initrd.gz (ramdisk image)
Finally, to configure the bootloader proceed to Section 5.1.3, “Booting from Linux Using LILO or GRUB”.