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 Section 5.3.1, “Floppy Disk Reliability” 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. Choose the flavor in Section 4.2.2, “Choosing the Right Installation Set” that best fits your taste, and you will be (almost) done.
Copy the following two or three files from the Debian archives in a convenient location on your hard drive, for instance in /boot/newinstall/.
vmlinuz (kernel binary)
initrd.gz (ramdisk image)
drivers.tgz (optional kernel modules)
Extract recursively everything now (easier than later). Remember on which physical partition (e.g. /dev/hda4) are the .o drivers you just extracted from drivers.tgz.
You can also replace vmlinuz and drivers.tgz by your custom kernel and the carefully chosen drivers that you will need for the installation, for instance a module for your exotic and unsupported network interface. Do not forget that your custom kernel must have (at least) the RAMDISK and initrd features built-in. See the very beginning of ??? for the list of the other mandatory built-in kernel features required to boot and launch the installer. The floppy-related stuff after the list of features is irrelevant to you.
Finally, to configure the bootloader proceed to Section 5.1.3, “Booting from linux using LILO or GRUB”.