lfs-book-zh_CN/chapter05/introduction.xml

<sect1 id="ch05-introduction">
<title>Introduction</title>
<?dbhtml filename="introduction.html" dir="chapter05"?>

<para>In this chapter we will compile and install a minimal
Linux system. This system will contain just enough tools to be able
to start constructing the final LFS system in the next chapter.</para>

<para>The building of this minimal system is done in two steps: first we
build a brand-new and host-independent toolchain (compiler, assembler,
linker and libraries), and then use this to build all the other essential
tools.</para>

<para>The files compiled in this chapter will be installed under the
<filename class="directory">$LFS/tools</filename> directory
to keep them separate from the files installed in the next chapter.
Since the packages compiled here are merely temporary, we don't want
them to pollute the soon-to-be LFS system.</para>

<para>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 this purpose a short summary of the content of each package is given
before the actual installation instructions. For a short description of
each program in a package, please refer to the corresponding section in
<xref linkend="appendixa"/>.</para>

<para>Several of the packages are patched before compilation, but only when
the patch is needed to circumvent a problem. Often the patch is needed in
both this and the next chapter, but sometimes in only one of them. Therefore,
don't worry when instructions for a downloaded patch seem to be missing.</para>

<para>During the installation of most packages you will
see all kinds of compiler warnings scroll by on your screen. These are
normal and can be safely ignored. They are just what they say they are:
warnings -- mostly about deprecated, but not invalid, use of the C or C++
syntax. It's just that C standards have changed rather often and some
packages still use the older standard, which is not really a problem.</para>

<para><emphasis>Unless</emphasis> told not to, you should normally delete the
source and build directories after installing each package -- for cleanness
sake and to save space.</para>

<para>Before continuing, make sure the LFS environment variable is set up
properly by executing the following:</para>

<screen><userinput>echo $LFS</userinput></screen>

<para>Make sure the output shows the path to your LFS partition's mount
point, which is <filename class="directory">/mnt/lfs</filename> if you
followed our example.</para>

</sect1>