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. On modern UEFI systems, the kernel may be booted directly from the UEFI partition without the need of a boot loader. A full, pure network installation can be achieved using this technique. This avoids all hassles of removable media, like finding and burning CD/DVD images. The installer cannot boot from files on an HFS+ file system. MacOS System 8.1 and above may use HFS+ file systems; NewWorld PowerMacs all use HFS+. To determine whether your existing file system is HFS+, select Get Info for the volume in question. HFS file systems appear as Mac OS Standard, while HFS+ file systems say Mac OS Extended. You must have an HFS partition in order to exchange files between MacOS and Linux, in particular the installation files you download. Different programs are used for hard disk installation system booting, depending on whether the system is a NewWorld or an OldWorld model. This section explains how to add to or even replace an existing linux installation using GRUB. At boot time, GRUB supports 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 /boot/newinstall/. vmlinuz (kernel binary) initrd.gz (ramdisk image) If you intend to use the hard drive only for booting and then download everything over the network, you should download the &x86-netboot-initrd; file and its corresponding kernel &x86-netboot-linux;. This will allow you to repartition the hard disk from which you boot the installer, although you should do so with care. Alternatively, if you intend to keep an existing partition on the hard drive unchanged during the install, you can download the &x86-hdmedia-initrd; file and its kernel &x86-hdmedia-vmlinuz;, as well as copy an installation image to the hard drive (make sure the file is named ending in .iso). The installer can then boot from the hard drive and install from the installation image, without needing the network. Finally, to configure the bootloader proceed to . This section explains how to prepare your hard drive for booting the installer from DOS using loadlin. Copy the following directories from a &debian; installation image to c:\. /&x86-install-dir; (kernel binary and ramdisk image) /tools (loadlin tool)