lfs-book/chapter06/introduction.xml

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<sect1 id="ch-system-introduction">
<title>Introduction</title>
<?dbhtml filename="introduction.html"?>

<para>In this chapter, we enter the building site and start
constructing the LFS system in earnest. That is, we chroot into the
temporary mini Linux system, make a few final preparations, and then
begin installing the packages.</para>

<para>The installation of this software is straightforward. Although
in many cases the installation instructions could be made shorter and
more generic, we have opted to provide the full instructions for every
package to minimize the possibilities for mistakes.  The key to
learning what makes a Linux system work is to know what each package
is used for and why the user (or the system) needs it.  For every
installed package, a summary of its contents is given, followed by
concise descriptions of each program and library the package
installed.</para>

<para>If using the compiler optimizations provided in this chapter,
please review the optimization hint at <ulink
url="&hints-root;optimization.txt"/>.  Compiler optimizations can make
a program run slightly faster, but they may also cause compilation
difficulties and problems when running the program. If a package
refuses to compile when using optimization, try to compile it without
optimization and see if that fixes the problem. Even if the package
does compile when using optimization, there is the risk it may have
been compiled incorrectly because of the complex interactions between
the code and build tools.  Also note that the <option>-march</option>
and <option>-mtune</option> options may cause problems with the
toolchain packages (Binutils, GCC and Glibc).  The small potential
gains achieved in using compiler optimizations are often outweighed by
the risks. First-time builders of LFS are encouraged to build without
custom optimizations.  The subsequent system will still run very fast
and be stable at the same time.</para>

<para>The order that packages are installed in this chapter needs to
be strictly followed to ensure that no program accidentally acquires a
path referring to <filename class="directory">/tools</filename>
hard-wired into it. For the same reason, do not compile packages in
parallel. Compiling in parallel may save time (especially on dual-CPU
machines), but it could result in a program containing a hard-wired
path to <filename class="directory">/tools</filename>, which will
cause the program to stop working when that directory is
removed.</para>

<para>Before the installation instructions, each installation page
provides information about the package, including a concise
description of what it contains, approximately how long it will take
to build, how much disk space is required during this building
process, and any other packages needed to successfully build the
package. Following the installation instructions, there is a list of
programs and libraries (along with brief descriptions of these) that
the package installs.</para>

<para>To keep track of which package installs particular files, a package
manager can be used. For a general overview of different styles of package
managers, please refer to <ulink
url="&blfs-root;view/svn/introduction/important.html"/>.
For a package management method specifically geared towards LFS, we recommend <ulink
url="&hints-root;more_control_and_pkg_man.txt"/>.</para>

<note><para>The remainder of this book is to be performed while logged in as
user <emphasis>root</emphasis> and no longer as user <emphasis>lfs</emphasis>.
Also, double check that <envar>$LFS</envar> is set.</para></note>

</sect1>