boots into stage 1 (kernel+initrd) succesfully.
`system-configuration.nix' contains the definition of the
configuration to be installed. The attribute systemConfiguration is
installed into the profile /nix/var/nix/profiles/system. Then the
program /nix/var/nix/profiles/system/bin/switch-to-configuration is
called to finalise the installation. This program (generated by
system-configuration.sh) installs Grub on the drive with a menu that
contains the entry for the desired kernel and initrd.
In principle this allows us to do rollbacks to previous system
configurations by doing `nix-env --rollback' and then calling
switch-to-configuration to update Grub. Ideally this should be done
in a single command (and we should consider the obvious risk of
garbage collecting the current kernel etc. to which the current Grub
menu points...).
Maybe the responsibility for generating the Grub menu should be
placed somewhere else. For instance, we could generate a Grub menu
automatically out of all the generations in the `system' profile.
svn path=/nixu/trunk/; revision=7009
