# Overview of the Installation Process

First, just a note about re-installations. With &debian;, a circumstance that will require a complete re-installation of your system is very rare; perhaps mechanical failure of the hard disk would be the most common case.

Many common operating systems may require a complete installation to be performed when critical failures take place or for upgrades to new OS versions. Even if a completely new installation isn't required, often the programs you use must be re-installed to operate properly in the new OS.

Under &debian-gnu;, it is much more likely that your OS can be repaired rather than replaced if things go wrong. Upgrades never require a wholesale installation; you can always upgrade in-place. And the programs are almost always compatible with successive OS releases. If a new program version requires newer supporting software, the &debian; packaging system ensures that all the necessary software is automatically identified and installed. The point is, much effort has been put into avoiding the need for re-installation, so think of it as your very last option. The installer is not designed to re-install over an existing system.

Here's a road map for the steps you will take during the installation process.

1. Back up any existing data or documents on the hard disk where you plan to install.

2. Gather information about your computer and any needed documentation, before starting the installation.

3. Create partitionable space for &debian; on your hard disk.

4. Locate and/or download the installer software and any specialized driver or firmware files your machine requires.

5. Set up boot media such as CDs/DVDs/USB sticks or provide a network boot infrastructure from which the installer can be booted.

6. Boot the installation system.

7. Select the installation language.

8. Activate the ethernet network connection, if available.

9. Configure one network interface.

10. Open an ssh connection to the new system.

11. Attach one or more DASDs (Direct Access Storage Device).

12. If necessary, resize existing partitions on your target harddisk to make space for the installation.

13. Create and mount the partitions on which &debian; will be installed.

14. Watch the automatic download/install/setup of the base system.

15. Select and install additional software.

16. Install a boot loader which can start up &debian-gnu; and/or your existing system.

17. Load the newly installed system for the first time.

For &arch-title; you have the option of using a an experimental an experimental graphical version of the installation system. For more information about this graphical installer, see graphical.

If you have problems during the installation, it helps to know which packages are involved in which steps. Introducing the leading software actors in this installation drama:

The installer software, `debian-installer`, is the primary concern of this manual. It detects hardware and loads appropriate drivers, uses `dhcp-client` to set up the network connection, runs `debootstrap` to install the base system packages, and runs `tasksel` to allow you to install certain additional software. Many more actors play smaller parts in this process, but `debian-installer` has completed its task when you load the new system for the first time.

To tune the system to your needs, `tasksel` allows you to choose to install various predefined bundles of software like a Web server or a Desktop environment.

One important option during the installation is whether or not to install a graphical desktop environment, consisting of the X Window System and one of the available graphical desktop environments. If you choose not to select the Desktop environment task, you will only have a relatively basic, command line driven system. Installing the Desktop environment task is optional because in relation to a text-mode-only system it requires a comparatively large amount of disk space and because many &debian-gnu; systems are servers which don't really have any need for a graphical user interface to do their job.

Just be aware that the X Window System is completely separate from `debian-installer`, and in fact is much more complicated. Troubleshooting of the X Window System is not within the scope of this manual.