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<sect1 id="ch-system-introduction">
<?dbhtml filename="introduction.html"?>
<title>Introduction</title>
<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>
<note>
<para>At this point, you may wish to keep your finished temporary
tools for use in future LFS builds by creating a tarball of the
<filename class="directory">/tools</filename> directory and
storing it in a safe location.</para>
</note>
</sect1>
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