Installation from optical disc is supported for most architectures.

USB flash disks a.k.a. USB memory sticks have become a commonly used and cheap storage device. Most modern computer systems also allow booting the debian-installer from such a stick. Many modern computer systems, in particular netbooks and thin laptops, do not have an optical drive anymore at all and booting from USB media is the standard way of installing a new operating system on them.

The network can be used during the installation to retrieve files needed for the installation. Whether the network is used or not depends on the installation method you choose and your answers to certain questions that will be asked during the installation. The installation system supports most types of network connections (including PPPoE, but not ISDN or PPP), via either HTTP or FTP. After the installation is completed, you can also configure your system to use ISDN and PPP.

You can also boot the installation system over the network without needing any local media like CDs/DVDs or USB sticks. If you already have a netboot-infrastructure available (i.e. you are already running DHCP and TFTP services in your network), this allows an easy and fast deployment of a large number of machines. Setting up the necessary infrastructure requires a certain level of technical experience, so this is not recommended for novice users.

Diskless installation, using network booting from a local area network and NFS-mounting of all local filesystems, is another option.

Booting the installation system directly from a hard disk is another option for many architectures. This will require some other operating system to load the installer onto the hard disk. This method is only recommended for special cases when no other installation method is available.

If you are running another Unix-like system, you could use it to install Debian GNU/Linux without using the debian-installer described in the rest of this manual. This kind of install may be useful for users with otherwise unsupported hardware or on hosts which can't afford downtime. If you are interested in this technique, skip to the Section D.3, “Installing Debian GNU/Linux from a Unix/Linux System”. This installation method is only recommended for advanced users when no other installation method is available.

The Debian installer contains a kernel which is built to maximize the number of systems it runs on.