Whenever you see “CD-ROM” in this manual, it applies to both CD-ROMs and DVD-ROMs, because both technologies are really the same from the operating system's point of view, except for some very old nonstandard CD-ROM drives which are neither SCSI nor IDE/ATAPI.

CD-ROM based installation is supported for some architectures. On machines which support bootable CD-ROMs, you should be able to do a completely floppy-less installation. Even if your system doesn't support booting from a CD-ROM, you can use the CD-ROM in conjunction with the other techniques to install your system, once you've booted up by other means; see Chapter 5, Booting the Installation System.

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.

Many Ubuntu boxes need their floppy and/or CD-ROM drives only for setting up the system and for rescue purposes. If you operate some servers, you will probably already have thought about omitting those drives and using an USB memory stick for installing and (when necessary) for recovering the system. This is also useful for small systems which have no room for unnecessary drives.

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.

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

If you are running another Unix-like system, you could use it to install Ubuntu 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 the section called “Installing Ubuntu from a Unix/Linux System”.

The Ubuntu boot disks contain a kernel which is built to maximize the number of systems it runs on. Unfortunately, this makes for a larger kernel, which includes many drivers that won't be used for your machine (see the section called “Compiling a New Kernel” to learn how to build your own kernel). Support for the widest possible range of devices is desirable in general, to ensure that Ubuntu can be installed on the widest array of hardware.

Any storage system supported by the Linux kernel is also supported by the boot system. Note that the current Linux kernel does not support floppies on CHRP systems at all.