## page was renamed from DebianInstallerConcepts
## Auto-converted by kwiki2moinmoin v2005-10-07
= Debian-Installer: Concepts =

'''Warning: This document is unmaintained and out of date.'''

In all there are three stages:

 * 1. Boot, hardware detection for network cards, get and unpack udebs.
 * 2. Discover remaining hardware, partitioning, base install, kernel image, boot loader, last minute fixes, reboot.
 * 3. base-config

== 1. Stage ==
=== 1.1 Boot ===
The boot is completely different on certain architectures.
Somehow the kernel and an initial ramdisk needs to be loaded.

=== 1.2 Pre-install ===
cdrom-detect calls hw-detect from the ddetect package. That one loads modules, which are on the initrd (mostly for nics) and stores the method to access the udebs and the architecture in debconf.

=== 1.3 anna loads udebs ===
Each debian-installer set has different udebs, which are needed to perform the following steps.

An udeb is a Debian package, which has no policy dependencies so you can remove documentation, licenses and unused options. They also should be as small as possible. See http://d-i.alioth.debian.org/svn/debian-installer/installer/doc/devel/modules.txt for details.

== 2. Stage 2 ==
=== 2.1 discover detects rest of the hardware ===
As now all kernel modules should be available so discover can detect the hardware.

=== 2.2 Partitioning ===
With autopartkit, partconf, partitioner, partman or similar tools the user can partition the harddisk.

This also differs on certain architectures. /target should after this step be mounted with one or more hard disk partitions.

=== 2.3 base-install ===
Now a base system installation will take place, which is an easy debootstrap, which might be replaced with cdebootstrap as this also takes care of dependencies. (see tasks)

=== 2.4 kernel-image ===
The user can select certain kernel images. They are found by apt-get search kernel-image. They will be installed by chrooting into the target system and installing it.

=== 2.5 Boot Loader ===
This is also a very architecture dependent step. Lilo/Grub for x86 is installed in the chroot, configured. Then the boot loader is installed.

=== 2.6 Last Minute Fixes ===
Prebaseconfig on system is run, the cdrom is unmounted and finally the installer reboots.

== 3. Stage 3 ==
base-config gets executed.

----

Tasks that came up in discussion were:

 * use of an SMP kernel to be able to detect it
 * Boot Loader automatic configurations should include other bootable partitions (done for some boot loaders)
 * minor: possibility to pivot_root into the system and not to reboot in last step of stage 2